core/*: Encapsulate blockchain data storage

This introduces a blockchain data storage package, `chaindb`. `chaindb.ChainDB`
serves as a layer between the blockchain (and headerchain and lightchain) and
the underlying key-value storage. It can be best thought of as the blockchain
data counterpart to `core/state/statedb` and ultimately a replacement for
`rawdb`*, whose code would be moved where it is currently being called within
`chaindb.ChainDB` whose use is a 1:1 mapping from before.**

The goals of this work are twofold:
1. Consolidate code interacting with storage.
2. With (1) in place continue the freezer work initiated #17814 inside.

Follow up work from this PR would be:
1. Use `chaindb.ChainDB` in the remaining places where `rawdb` is being used.
2. Migrate the various caches used between `ethdb.Database` inside the storage
   and also expose tuning options to set them.
3. Continue with the freezer work.

This also introduces the `github.com/google/go-cmp/cmp/cmpopts` package,
which is used for the tests added for this work.

* The only exception is `WritePreimages` which is really a `StateDB`
concept, however it is included as it is currently stored/retrieved
through methods in `rawdb`.
** The only exception is `WriteCanonicalHash` whose method parameter order
was swapped as the `number` is the key and the `hash` is the value being
mapped to it, making it consistent with the "key" then "value" convention
the remaining methods use.

cmd/geth/chaincmd.go

@@ -29,6 +29,7 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/console"
 	"github.com/ethereum/go-ethereum/core"
+	"github.com/ethereum/go-ethereum/core/chaindb"
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/eth/downloader"
@@ -390,7 +391,7 @@ func copyDb(ctx *cli.Context) error {
 	if err != nil {
 		return err
 	}
-	hc, err := core.NewHeaderChain(db, chain.Config(), chain.Engine(), func() bool { return false })
+	hc, err := core.NewHeaderChain(chaindb.Wrap(db), chain.Config(), chain.Engine(), func() bool { return false })
 	if err != nil {
 		return err
 	}

core/blockchain.go

@@ -31,7 +31,7 @@ import (
 	"github.com/ethereum/go-ethereum/common/mclock"
 	"github.com/ethereum/go-ethereum/common/prque"
 	"github.com/ethereum/go-ethereum/consensus"
-	"github.com/ethereum/go-ethereum/core/rawdb"
+	"github.com/ethereum/go-ethereum/core/chaindb"
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/core/vm"
@@ -102,6 +102,7 @@ type BlockChain struct {
 	cacheConfig *CacheConfig        // Cache configuration for pruning
 
 	db      ethdb.Database // Low level persistent database to store final content in
+	chainDB *chaindb.ChainDB
 	triegc  *prque.Prque  // Priority queue mapping block numbers to tries to gc
 	gcproc  time.Duration // Accumulates canonical block processing for trie dumping
 
@@ -162,10 +163,12 @@ func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, chainConfig *par
 	futureBlocks, _ := lru.New(maxFutureBlocks)
 	badBlocks, _ := lru.New(badBlockLimit)
 
+	chainDB := chaindb.Wrap(db)
 	bc := &BlockChain{
 		chainConfig:    chainConfig,
 		cacheConfig:    cacheConfig,
 		db:             db,
+		chainDB:        chainDB,
 		triegc:         prque.New(nil),
 		stateCache:     state.NewDatabaseWithCache(db, cacheConfig.TrieCleanLimit),
 		quit:           make(chan struct{}),
@@ -183,7 +186,7 @@ func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, chainConfig *par
 	bc.SetProcessor(NewStateProcessor(chainConfig, bc, engine))
 
 	var err error
-	bc.hc, err = NewHeaderChain(db, chainConfig, engine, bc.getProcInterrupt)
+	bc.hc, err = NewHeaderChain(chainDB, chainConfig, engine, bc.getProcInterrupt)
 	if err != nil {
 		return nil, err
 	}
@@ -225,7 +228,7 @@ func (bc *BlockChain) GetVMConfig() *vm.Config {
 // assumes that the chain manager mutex is held.
 func (bc *BlockChain) loadLastState() error {
 	// Restore the last known head block
-	head := rawdb.ReadHeadBlockHash(bc.db)
+	head := bc.chainDB.ReadHeadBlockHash()
 	if head == (common.Hash{}) {
 		// Corrupt or empty database, init from scratch
 		log.Warn("Empty database, resetting chain")
@@ -251,7 +254,7 @@ func (bc *BlockChain) loadLastState() error {
 
 	// Restore the last known head header
 	currentHeader := currentBlock.Header()
-	if head := rawdb.ReadHeadHeaderHash(bc.db); head != (common.Hash{}) {
+	if head := bc.chainDB.ReadHeadHeaderHash(); head != (common.Hash{}) {
 		if header := bc.GetHeaderByHash(head); header != nil {
 			currentHeader = header
 		}
@@ -260,7 +263,7 @@ func (bc *BlockChain) loadLastState() error {
 
 	// Restore the last known head fast block
 	bc.currentFastBlock.Store(currentBlock)
-	if head := rawdb.ReadHeadFastBlockHash(bc.db); head != (common.Hash{}) {
+	if head := bc.chainDB.ReadHeadFastBlockHash(); head != (common.Hash{}) {
 		if block := bc.GetBlockByHash(head); block != nil {
 			bc.currentFastBlock.Store(block)
 		}
@@ -291,8 +294,8 @@ func (bc *BlockChain) SetHead(head uint64) error {
 	defer bc.chainmu.Unlock()
 
 	// Rewind the header chain, deleting all block bodies until then
-	delFn := func(db rawdb.DatabaseDeleter, hash common.Hash, num uint64) {
+	delFn := func(batch *chaindb.Batch, hash common.Hash, num uint64) {
-		rawdb.DeleteBody(db, hash, num)
+		batch.DeleteBody(hash, num)
 	}
 	bc.hc.SetHead(head, delFn)
 	currentHeader := bc.hc.CurrentHeader()
@@ -328,8 +331,8 @@ func (bc *BlockChain) SetHead(head uint64) error {
 	currentBlock := bc.CurrentBlock()
 	currentFastBlock := bc.CurrentFastBlock()
 
-	rawdb.WriteHeadBlockHash(bc.db, currentBlock.Hash())
+	bc.chainDB.WriteHeadBlockHash(currentBlock.Hash())
-	rawdb.WriteHeadFastBlockHash(bc.db, currentFastBlock.Hash())
+	bc.chainDB.WriteHeadFastBlockHash(currentFastBlock.Hash())
 
 	return bc.loadLastState()
 }
@@ -433,7 +436,7 @@ func (bc *BlockChain) ResetWithGenesisBlock(genesis *types.Block) error {
 	if err := bc.hc.WriteTd(genesis.Hash(), genesis.NumberU64(), genesis.Difficulty()); err != nil {
 		log.Crit("Failed to write genesis block TD", "err", err)
 	}
-	rawdb.WriteBlock(bc.db, genesis)
+	bc.chainDB.WriteBlock(genesis)
 
 	bc.genesisBlock = genesis
 	bc.insert(bc.genesisBlock)
@@ -507,18 +510,18 @@ func (bc *BlockChain) ExportN(w io.Writer, first uint64, last uint64) error {
 // Note, this function assumes that the `mu` mutex is held!
 func (bc *BlockChain) insert(block *types.Block) {
 	// If the block is on a side chain or an unknown one, force other heads onto it too
-	updateHeads := rawdb.ReadCanonicalHash(bc.db, block.NumberU64()) != block.Hash()
+	updateHeads := bc.chainDB.ReadCanonicalHash(block.NumberU64()) != block.Hash()
 
 	// Add the block to the canonical chain number scheme and mark as the head
-	rawdb.WriteCanonicalHash(bc.db, block.Hash(), block.NumberU64())
+	bc.chainDB.WriteCanonicalHash(block.NumberU64(), block.Hash())
-	rawdb.WriteHeadBlockHash(bc.db, block.Hash())
+	bc.chainDB.WriteHeadBlockHash(block.Hash())
 
 	bc.currentBlock.Store(block)
 
 	// If the block is better than our head or is on a different chain, force update heads
 	if updateHeads {
 		bc.hc.SetCurrentHeader(block.Header())
-		rawdb.WriteHeadFastBlockHash(bc.db, block.Hash())
+		bc.chainDB.WriteHeadFastBlockHash(block.Hash())
 
 		bc.currentFastBlock.Store(block)
 	}
@@ -541,7 +544,7 @@ func (bc *BlockChain) GetBody(hash common.Hash) *types.Body {
 	if number == nil {
 		return nil
 	}
-	body := rawdb.ReadBody(bc.db, hash, *number)
+	body := bc.chainDB.ReadBody(hash, *number)
 	if body == nil {
 		return nil
 	}
@@ -561,7 +564,7 @@ func (bc *BlockChain) GetBodyRLP(hash common.Hash) rlp.RawValue {
 	if number == nil {
 		return nil
 	}
-	body := rawdb.ReadBodyRLP(bc.db, hash, *number)
+	body := bc.chainDB.ReadBodyRLP(hash, *number)
 	if len(body) == 0 {
 		return nil
 	}
@@ -575,7 +578,7 @@ func (bc *BlockChain) HasBlock(hash common.Hash, number uint64) bool {
 	if bc.blockCache.Contains(hash) {
 		return true
 	}
-	return rawdb.HasBody(bc.db, hash, number)
+	return bc.chainDB.HasBody(hash, number)
 }
 
 // HasFastBlock checks if a fast block is fully present in the database or not.
@@ -586,7 +589,7 @@ func (bc *BlockChain) HasFastBlock(hash common.Hash, number uint64) bool {
 	if bc.receiptsCache.Contains(hash) {
 		return true
 	}
-	return rawdb.HasReceipts(bc.db, hash, number)
+	return bc.chainDB.HasReceipts(hash, number)
 }
 
 // HasState checks if state trie is fully present in the database or not.
@@ -613,7 +616,7 @@ func (bc *BlockChain) GetBlock(hash common.Hash, number uint64) *types.Block {
 	if block, ok := bc.blockCache.Get(hash); ok {
 		return block.(*types.Block)
 	}
-	block := rawdb.ReadBlock(bc.db, hash, number)
+	block := bc.chainDB.ReadBlock(hash, number)
 	if block == nil {
 		return nil
 	}
@@ -634,7 +637,7 @@ func (bc *BlockChain) GetBlockByHash(hash common.Hash) *types.Block {
 // GetBlockByNumber retrieves a block from the database by number, caching it
 // (associated with its hash) if found.
 func (bc *BlockChain) GetBlockByNumber(number uint64) *types.Block {
-	hash := rawdb.ReadCanonicalHash(bc.db, number)
+	hash := bc.chainDB.ReadCanonicalHash(number)
 	if hash == (common.Hash{}) {
 		return nil
 	}
@@ -646,11 +649,11 @@ func (bc *BlockChain) GetReceiptsByHash(hash common.Hash) types.Receipts {
 	if receipts, ok := bc.receiptsCache.Get(hash); ok {
 		return receipts.(types.Receipts)
 	}
-	number := rawdb.ReadHeaderNumber(bc.db, hash)
+	number := bc.chainDB.ReadHeaderNumber(hash)
 	if number == nil {
 		return nil
 	}
-	receipts := rawdb.ReadReceipts(bc.db, hash, *number)
+	receipts := bc.chainDB.ReadReceipts(hash, *number)
 	if receipts == nil {
 		return nil
 	}
@@ -777,12 +780,12 @@ func (bc *BlockChain) Rollback(chain []common.Hash) {
 		if currentFastBlock := bc.CurrentFastBlock(); currentFastBlock.Hash() == hash {
 			newFastBlock := bc.GetBlock(currentFastBlock.ParentHash(), currentFastBlock.NumberU64()-1)
 			bc.currentFastBlock.Store(newFastBlock)
-			rawdb.WriteHeadFastBlockHash(bc.db, newFastBlock.Hash())
+			bc.chainDB.WriteHeadFastBlockHash(newFastBlock.Hash())
 		}
 		if currentBlock := bc.CurrentBlock(); currentBlock.Hash() == hash {
 			newBlock := bc.GetBlock(currentBlock.ParentHash(), currentBlock.NumberU64()-1)
 			bc.currentBlock.Store(newBlock)
-			rawdb.WriteHeadBlockHash(bc.db, newBlock.Hash())
+			bc.chainDB.WriteHeadBlockHash(newBlock.Hash())
 		}
 	}
 }
@@ -845,7 +848,7 @@ func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain [
 		stats = struct{ processed, ignored int32 }{}
 		start = time.Now()
 		bytes = 0
-		batch = bc.db.NewBatch()
+		batch = bc.chainDB.NewBatch()
 	)
 	for i, block := range blockChain {
 		receipts := receiptChain[i]
@@ -867,9 +870,9 @@ func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain [
 			return i, fmt.Errorf("failed to set receipts data: %v", err)
 		}
 		// Write all the data out into the database
-		rawdb.WriteBody(batch, block.Hash(), block.NumberU64(), block.Body())
+		batch.WriteBody(block.Hash(), block.NumberU64(), block.Body())
-		rawdb.WriteReceipts(batch, block.Hash(), block.NumberU64(), receipts)
+		batch.WriteReceipts(block.Hash(), block.NumberU64(), receipts)
-		rawdb.WriteTxLookupEntries(batch, block)
+		batch.WriteTxLookupEntries(block)
 
 		stats.processed++
 
@@ -894,7 +897,7 @@ func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain [
 	if td := bc.GetTd(head.Hash(), head.NumberU64()); td != nil { // Rewind may have occurred, skip in that case
 		currentFastBlock := bc.CurrentFastBlock()
 		if bc.GetTd(currentFastBlock.Hash(), currentFastBlock.NumberU64()).Cmp(td) < 0 {
-			rawdb.WriteHeadFastBlockHash(bc.db, head.Hash())
+			bc.chainDB.WriteHeadFastBlockHash(head.Hash())
 			bc.currentFastBlock.Store(head)
 		}
 	}
@@ -925,7 +928,7 @@ func (bc *BlockChain) WriteBlockWithoutState(block *types.Block, td *big.Int) (e
 	if err := bc.hc.WriteTd(block.Hash(), block.NumberU64(), td); err != nil {
 		return err
 	}
-	rawdb.WriteBlock(bc.db, block)
+	bc.chainDB.WriteBlock(block)
 
 	return nil
 }
@@ -958,7 +961,7 @@ func (bc *BlockChain) writeBlockWithState(block *types.Block, receipts []*types.
 	if err := bc.hc.WriteTd(block.Hash(), block.NumberU64(), externTd); err != nil {
 		return NonStatTy, err
 	}
-	rawdb.WriteBlock(bc.db, block)
+	bc.chainDB.WriteBlock(block)
 
 	root, err := state.Commit(bc.chainConfig.IsEIP158(block.Number()))
 	if err != nil {
@@ -1020,8 +1023,8 @@ func (bc *BlockChain) writeBlockWithState(block *types.Block, receipts []*types.
 	}
 
 	// Write other block data using a batch.
-	batch := bc.db.NewBatch()
+	batch := bc.chainDB.NewBatch()
-	rawdb.WriteReceipts(batch, block.Hash(), block.NumberU64(), receipts)
+	batch.WriteReceipts(block.Hash(), block.NumberU64(), receipts)
 
 	// If the total difficulty is higher than our known, add it to the canonical chain
 	// Second clause in the if statement reduces the vulnerability to selfish mining.
@@ -1049,8 +1052,8 @@ func (bc *BlockChain) writeBlockWithState(block *types.Block, receipts []*types.
 			}
 		}
 		// Write the positional metadata for transaction/receipt lookups and preimages
-		rawdb.WriteTxLookupEntries(batch, block)
+		batch.WriteTxLookupEntries(block)
-		rawdb.WritePreimages(batch, state.Preimages())
+		batch.WritePreimages(state.Preimages())
 
 		status = CanonStatTy
 	} else {
@@ -1441,7 +1444,7 @@ func (bc *BlockChain) reorg(oldBlock, newBlock *types.Block) error {
 			if number == nil {
 				return
 			}
-			receipts := rawdb.ReadReceipts(bc.db, hash, *number)
+			receipts := bc.chainDB.ReadReceipts(hash, *number)
 			for _, receipt := range receipts {
 				for _, log := range receipt.Logs {
 					del := *log
@@ -1510,16 +1513,16 @@ func (bc *BlockChain) reorg(oldBlock, newBlock *types.Block) error {
 		// insert the block in the canonical way, re-writing history
 		bc.insert(newChain[i])
 		// write lookup entries for hash based transaction/receipt searches
-		rawdb.WriteTxLookupEntries(bc.db, newChain[i])
+		bc.chainDB.WriteTxLookupEntries(newChain[i])
 		addedTxs = append(addedTxs, newChain[i].Transactions()...)
 	}
 	// calculate the difference between deleted and added transactions
 	diff := types.TxDifference(deletedTxs, addedTxs)
 	// When transactions get deleted from the database that means the
 	// receipts that were created in the fork must also be deleted
-	batch := bc.db.NewBatch()
+	batch := bc.chainDB.NewBatch()
 	for _, tx := range diff {
-		rawdb.DeleteTxLookupEntry(batch, tx.Hash())
+		batch.DeleteTxLookupEntry(tx.Hash())
 	}
 	batch.Write()
 

core/chaindb/chaindb.go

@@ -0,0 +1,293 @@
+// Copyright 2019 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+package chaindb
+
+import (
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/rawdb"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/rlp"
+)
+
+// ChainDB is the blockchain data storage layer. It provides the ability
+// to retrieve, store, and delete the various constructs (i.e. headers,
+// receipts) and metadata (i.e. header hash mappings, transaction locations).
+type ChainDB struct {
+	writer
+
+	db ethdb.Database
+}
+
+// Batch consolidates writes and deletions to the ChainDB it originated
+// from. The changes will be committed when Write is called.
+type Batch struct {
+	writer
+
+	batch ethdb.Batch
+}
+
+// Consolidates shared writing and deleting code used by both ChainDB and Batch.
+// Note that this considers deleting to be a form of writing unlike ethdb.
+type writer struct {
+	db ethdbPutterAndDeleter
+}
+
+// Composite type to enable both putting and deleting.
+type ethdbPutterAndDeleter interface {
+	ethdb.Putter
+	ethdb.Deleter
+}
+
+// Wrap creates a new ChainDB that uses the specified database as its
+// underlying data store.
+func Wrap(db ethdb.Database) *ChainDB {
+	return &ChainDB{writer{db}, db}
+}
+
+// Returns a Batch associated with the ChainDB.
+func (c *ChainDB) NewBatch() *Batch {
+	return newBatch(c.db.NewBatch())
+}
+
+func newBatch(batch ethdb.Batch) *Batch {
+	return &Batch{writer{batch}, batch}
+}
+
+// Write commits the changes within the batch to its associated ChainDB.
+func (b *Batch) Write() error {
+	return b.batch.Write()
+}
+
+// Reset drops all pending changes contained in the batch.
+func (b *Batch) Reset() {
+	b.batch.Reset()
+}
+
+// Value size returns the number of changes pending in the batch.
+func (b *Batch) ValueSize() int {
+	return b.batch.ValueSize()
+}
+
+// ReadHeadHeaderHash retrieves the current canonical head header hash.
+func (c *ChainDB) ReadHeadHeaderHash() common.Hash {
+	return rawdb.ReadHeadHeaderHash(c.db)
+}
+
+// WriteHeadHeaderHash stores the current canonical head header hash.
+func (w *writer) WriteHeadHeaderHash(hash common.Hash) {
+	rawdb.WriteHeadHeaderHash(w.db, hash)
+}
+
+// ReadHeadBlockHash retrieves the current canonical head block hash.
+//
+// Note that this is different from the canonical head header hash as
+// this corresponds to all block data and not just the header.
+func (c *ChainDB) ReadHeadBlockHash() common.Hash {
+	return rawdb.ReadHeadBlockHash(c.db)
+}
+
+// WriteHeadBlockHash stores the current fast-sync head block hash.
+func (w *writer) WriteHeadBlockHash(hash common.Hash) {
+	rawdb.WriteHeadBlockHash(w.db, hash)
+}
+
+// ReadHeadFastBlockHash retrieves the current fast-sync head block hash.
+func (c *ChainDB) ReadHeadFastBlockHash() common.Hash {
+	return rawdb.ReadHeadFastBlockHash(c.db)
+}
+
+// WriteHeadFastBlockHash stores the current head block hash.
+//
+// Note that this is different from the canonical head header hash as
+// this corresponds to all block data and not just the header.
+func (w *writer) WriteHeadFastBlockHash(hash common.Hash) {
+	rawdb.WriteHeadFastBlockHash(w.db, hash)
+}
+
+// ReadCanonicalHash retrieves the canonical hash for a block number,
+// returning a common.Hash{} if it does not exist.
+func (c *ChainDB) ReadCanonicalHash(number uint64) common.Hash {
+	return rawdb.ReadCanonicalHash(c.db, number)
+}
+
+// WriteCanonicalHash stores the canoical hash assigned to a block number.
+func (w *writer) WriteCanonicalHash(number uint64, hash common.Hash) {
+	rawdb.WriteCanonicalHash(w.db, hash, number)
+}
+
+// DeleteCanonicalHash removes the number to canonical hash mapping.
+func (w *writer) DeleteCanonicalHash(number uint64) {
+	rawdb.DeleteCanonicalHash(w.db, number)
+}
+
+// ReadHeaderNumber returns the header number assigned to a hash.
+func (c *ChainDB) ReadHeaderNumber(hash common.Hash) *uint64 {
+	return rawdb.ReadHeaderNumber(c.db, hash)
+}
+
+// writeHeaderNumber associates the block number with the hash.
+func (w *writer) writeHeaderNumber(hash common.Hash, number uint64) {
+	rawdb.WriteHeaderNumber(w.db, hash, number)
+}
+
+// HasHeader returns whether the block header associated with the
+// specified hash and number pair is currently stored.
+func (c *ChainDB) HasHeader(hash common.Hash, number uint64) bool {
+	return rawdb.HasHeader(c.db, hash, number)
+}
+
+// ReadHeader returns the block header associated with the specified
+// hash and number pair.
+func (c *ChainDB) ReadHeader(hash common.Hash, number uint64) *types.Header {
+	return rawdb.ReadHeader(c.db, hash, number)
+}
+
+// WriteHeader stores the block header, including its associated
+// hash-to-number mapping.
+func (w *writer) WriteHeader(header *types.Header) {
+	rawdb.WriteHeader(w.db, header)
+}
+
+// DeleteHeader removes the block header and its associated
+// hash-to-number mapping.
+func (w *writer) DeleteHeader(hash common.Hash, number uint64) {
+	rawdb.DeleteHeader(w.db, hash, number)
+}
+
+// HasBody returns whether the block body associated with the
+// specified hash and number pair is currently stored.
+func (c *ChainDB) HasBody(hash common.Hash, number uint64) bool {
+	return rawdb.HasBody(c.db, hash, number)
+}
+
+// ReadBody returns the block body associated with the specified
+// hash and number pair.
+func (c *ChainDB) ReadBody(hash common.Hash, number uint64) *types.Body {
+	return rawdb.ReadBody(c.db, hash, number)
+}
+
+// WriteBody stores the block body associated with hash and number.
+func (w *writer) WriteBody(hash common.Hash, number uint64, body *types.Body) {
+	rawdb.WriteBody(w.db, hash, number, body)
+}
+
+// DeleteBody removes the block body associated with the specified hash
+// and number pair.
+func (w *writer) DeleteBody(hash common.Hash, number uint64) {
+	rawdb.DeleteBody(w.db, hash, number)
+}
+
+// ReadBodyRLP returns the RLP-encoded block body associated with the specified
+// hash and number pair.
+func (c *ChainDB) ReadBodyRLP(hash common.Hash, number uint64) rlp.RawValue {
+	return rawdb.ReadBodyRLP(c.db, hash, number)
+}
+
+// ReadBlock returns the block associated with the specified hash and
+// number pair.
+func (c *ChainDB) ReadBlock(hash common.Hash, number uint64) *types.Block {
+	return rawdb.ReadBlock(c.db, hash, number)
+}
+
+// WriteBlock stores the block (header and body), including its associated
+// hash-to-number mapping.
+func (w *writer) WriteBlock(block *types.Block) {
+	rawdb.WriteBlock(w.db, block)
+}
+
+// DeleteBlock removes the block, receipts and other metadata associated
+// with the specified hash and number pair.
+func (w *writer) DeleteBlock(hash common.Hash, number uint64) {
+	rawdb.DeleteBody(w.db, hash, number)
+}
+
+// HasHeader returns whether the transaction receipts associated with
+// the specified hash and number pair is currently stored.
+func (c *ChainDB) HasReceipts(hash common.Hash, number uint64) bool {
+	return rawdb.HasReceipts(c.db, hash, number)
+}
+
+// ReadReceipts returns the transaction receipts in the block with the
+// specified hash and number pair.
+func (c *ChainDB) ReadReceipts(hash common.Hash, number uint64) types.Receipts {
+	return rawdb.ReadReceipts(c.db, hash, number)
+}
+
+// WriteReceipts stores transaction receipts associated with the hash and
+// number pair.
+func (w *writer) WriteReceipts(hash common.Hash, number uint64, receipts types.Receipts) {
+	rawdb.WriteReceipts(w.db, hash, number, receipts)
+}
+
+// DeleteReceipts removes transaction receipts associated with the hash and
+// number pair.
+func (w *writer) DeleteReceipts(hash common.Hash, number uint64) {
+	rawdb.DeleteReceipts(w.db, hash, number)
+}
+
+// ReadTD returns the total difficulty associated with the specified
+// specified block header hash and number pair.
+func (c *ChainDB) ReadTD(hash common.Hash, number uint64) *big.Int {
+	return rawdb.ReadTd(c.db, hash, number)
+}
+
+// WriteTd stores the total difficulty associated with the specified
+// hash and number pair.
+func (w *writer) WriteTD(hash common.Hash, number uint64, td *big.Int) {
+	rawdb.WriteTd(w.db, hash, number, td)
+}
+
+// DeleteTd removes the total difficulty data associated with the specified
+// hash and number pair.
+func (w *writer) DeleteTD(hash common.Hash, number uint64) {
+	rawdb.DeleteTd(w.db, hash, number)
+}
+
+// ReadTxLookupEntry retrieves the block hash the transaction is located in.
+func (c *ChainDB) ReadTxLookupEntry(hash common.Hash) common.Hash {
+	return rawdb.ReadTxLookupEntry(c.db, hash)
+}
+
+// WriteTxLookupEntries stores the block hash each of the transactions
+// within the block are stored in, enabling hash based transaction and receipt lookups.
+
+// Note that the block hash-to-number mapping and block body is assumed to have been stored
+// already by  WriteBlock.
+func (w *writer) WriteTxLookupEntries(block *types.Block) {
+	rawdb.WriteTxLookupEntries(w.db, block)
+}
+
+// DeleteTxLookupEntry removes the lookup metadat for transaction hash.
+func (w *writer) DeleteTxLookupEntry(hash common.Hash) {
+	rawdb.DeleteTxLookupEntry(w.db, hash)
+}
+
+func (c *ChainDB) ReadTransaction(hash common.Hash) (*types.Transaction, common.Hash, uint64, uint64) {
+	return rawdb.ReadTransaction(c.db, hash)
+}
+
+// ReadPreimage retrieves a the preimage of the hash.
+func (c *ChainDB) ReadPreimage(hash common.Hash) []byte {
+	return rawdb.ReadPreimage(c.db, hash)
+}
+
+// WritePreimages stores the provided preimage mappings.
+func (w *writer) WritePreimages(preimages map[common.Hash][]byte) {
+	rawdb.WritePreimages(w.db, preimages)
+}

core/chaindb/chaindb_test.go

@@ -0,0 +1,579 @@
+// Copyright 2019 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+package chaindb
+
+import (
+	"bytes"
+	"encoding/hex"
+	"fmt"
+	"math/big"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
+)
+
+type testWriter interface {
+	WriteHeadHeaderHash(common.Hash)
+	WriteHeadBlockHash(common.Hash)
+	WriteHeadFastBlockHash(common.Hash)
+	WriteCanonicalHash(uint64, common.Hash)
+	DeleteCanonicalHash(uint64)
+	writeHeaderNumber(common.Hash, uint64)
+	WriteHeader(*types.Header)
+	DeleteHeader(common.Hash, uint64)
+	WriteBody(common.Hash, uint64, *types.Body)
+	DeleteBody(common.Hash, uint64)
+	WriteBlock(*types.Block)
+	DeleteBlock(common.Hash, uint64)
+	WriteReceipts(common.Hash, uint64, types.Receipts)
+	DeleteReceipts(common.Hash, uint64)
+	WriteTD(common.Hash, uint64, *big.Int)
+	DeleteTD(common.Hash, uint64)
+	WriteTxLookupEntries(*types.Block)
+	DeleteTxLookupEntry(common.Hash)
+	WritePreimages(preimages map[common.Hash][]byte)
+}
+
+var tests = []struct {
+	name          string
+	createWrapper func(*ChainDB) *testWriterWrapper
+}{
+	{
+		"ChainDB",
+		chainDBWrapper,
+	},
+	{
+		"Batch",
+		batchWrapper,
+	},
+}
+
+func chainDBWrapper(chainDB *ChainDB) *testWriterWrapper {
+	return &testWriterWrapper{
+		chainDB,
+		func() error {
+			return nil
+		},
+	}
+}
+
+func batchWrapper(chainDB *ChainDB) *testWriterWrapper {
+	batch := chainDB.NewBatch()
+	return &testWriterWrapper{
+		batch,
+		func() error {
+			return batch.Write()
+		},
+	}
+}
+
+type testWriterWrapper struct {
+	writer testWriter
+	done   func() error
+}
+
+func TestChainDB_ReadWriteHeadHeaderHash(t *testing.T) {
+	for _, tc := range tests {
+		tc := tc // Capture test case.
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			db := ethdb.NewMemDatabase()
+			chainDB := Wrap(db)
+			wrapper := tc.createWrapper(chainDB)
+
+			want := common.HexToHash("0x1")
+
+			if got := chainDB.ReadHeadHeaderHash(); got != (common.Hash{}) {
+				t.Fatalf("chainDB.ReadHeadHeaderHash() = %v, want %v", got, common.Hash{})
+			}
+
+			wrapper.writer.WriteHeadHeaderHash(want)
+			if err := wrapper.done(); err != nil {
+				t.Fatalf("wrapper.done() = %v, want <nil>", err)
+			}
+
+			if got := chainDB.ReadHeadHeaderHash(); got != want {
+				t.Fatalf("chainDB.ReadHeadHeaderHash() = %v, want %v", got, want)
+			}
+		})
+	}
+}
+
+func TestChainDB_ReadWriteHeadBlockHash(t *testing.T) {
+	for _, tc := range tests {
+		tc := tc // Capture test case.
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			db := ethdb.NewMemDatabase()
+			chainDB := Wrap(db)
+			wrapper := tc.createWrapper(chainDB)
+
+			want := common.HexToHash("0x1")
+
+			if got := chainDB.ReadHeadBlockHash(); got != (common.Hash{}) {
+				t.Fatalf("chainDB.ReadHeadBlockHash() = %v, want %v", got, common.Hash{})
+			}
+
+			wrapper.writer.WriteHeadBlockHash(want)
+			if err := wrapper.done(); err != nil {
+				t.Fatalf("wrapper.done() = %v, want <nil>", err)
+			}
+
+			if got := chainDB.ReadHeadBlockHash(); got != want {
+				t.Fatalf("chainDB.ReadHeadBlockHash() = %v, want %v", got, want)
+			}
+		})
+	}
+}
+
+func TestChainDB_ReadWriteHeadFastBlockHash(t *testing.T) {
+	for _, tc := range tests {
+		tc := tc // Capture test case.
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			db := ethdb.NewMemDatabase()
+			chainDB := Wrap(db)
+			wrapper := tc.createWrapper(chainDB)
+
+			want := common.HexToHash("0x1")
+
+			if got := chainDB.ReadHeadFastBlockHash(); got != (common.Hash{}) {
+				t.Fatalf("chainDB.ReadHeadFastBlockHash() = %v, want %v", got, common.Hash{})
+			}
+
+			wrapper.writer.WriteHeadFastBlockHash(want)
+			if err := wrapper.done(); err != nil {
+				t.Fatalf("wrapper.done() = %v, want <nil>", err)
+			}
+
+			if got := chainDB.ReadHeadFastBlockHash(); got != want {
+				t.Fatalf("chainDB.ReadFastHeadBlockHash() = %v, want %v", got, want)
+			}
+		})
+	}
+}
+
+func TestChainDB_ReadWriteDeleteCanonicalHash(t *testing.T) {
+	for _, tc := range tests {
+		tc := tc // Capture test case.
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			db := ethdb.NewMemDatabase()
+			chainDB := Wrap(db)
+			wrapper := tc.createWrapper(chainDB)
+
+			number := uint64(22)
+			want := common.HexToHash("0x1")
+
+			if got := chainDB.ReadCanonicalHash(number); got != (common.Hash{}) {
+				t.Fatalf("chainDB.ReadCanonicalHash(%d) = %v, want %v", number, got, common.Hash{})
+			}
+
+			wrapper.writer.WriteCanonicalHash(number, want)
+			if err := wrapper.done(); err != nil {
+				t.Fatalf("wrapper.done() = %v, want <nil>", err)
+			}
+
+			if got := chainDB.ReadCanonicalHash(number); got != want {
+				t.Fatalf("chainDB.ReadCanonicalHash(%d) = %+v, want %+v", number, got, want)
+			}
+
+			wrapper.writer.DeleteCanonicalHash(number)
+			if err := wrapper.done(); err != nil {
+				t.Fatalf("wrapper.done() = %v, want <nil>", err)
+			}
+
+			if got := chainDB.ReadCanonicalHash(number); got != (common.Hash{}) {
+				t.Fatalf("chainDB.ReadCanonicalHash(%d) = %v, want %v", number, got, common.Hash{})
+			}
+		})
+	}
+}
+
+func TestChainDB_ReadWriteHeaderNumber(t *testing.T) {
+	for _, tc := range tests {
+		tc := tc // Capture test case.
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			db := ethdb.NewMemDatabase()
+			chainDB := Wrap(db)
+			wrapper := tc.createWrapper(chainDB)
+
+			hash := common.HexToHash("0x1")
+			want := uint64(1)
+
+			if got := chainDB.ReadHeaderNumber(hash); got != nil {
+				t.Fatalf("chainDB.ReadHeaderNumber(%q) = %d, want <nil>", hash.String(), *got)
+			}
+
+			wrapper.writer.writeHeaderNumber(hash, want)
+			if err := wrapper.done(); err != nil {
+				t.Fatalf("wrapper.done() = %v, want <nil>", err)
+			}
+
+			if got := chainDB.ReadHeaderNumber(hash); got == nil {
+				t.Fatalf("chainDB.ReadHeaderNumber(%q) = <nil>, want %d", hash.String(), want)
+			} else if *got != want {
+				t.Fatalf("chainDB.ReadHeaderNumber(%q) = %d, want %d", hash.String(), *got, want)
+			}
+		})
+	}
+
+}
+
+func TestChainDB_HasReadWriteDeleteHeader(t *testing.T) {
+	for _, tc := range tests {
+		tc := tc // Capture test case.
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			db := ethdb.NewMemDatabase()
+			chainDB := Wrap(db)
+			wrapper := tc.createWrapper(chainDB)
+
+			want := &types.Header{Number: big.NewInt(1), Difficulty: big.NewInt(2), Time: big.NewInt(3), Extra: []byte("test header")}
+
+			if present := chainDB.HasHeader(want.Hash(), want.Number.Uint64()); present {
+				t.Fatalf("chainDB.HasHeader(%q, %d) = true, want false", want.Hash().String(), want.Number.Uint64())
+			}
+
+			if got := chainDB.ReadHeader(want.Hash(), want.Number.Uint64()); got != nil {
+				t.Fatalf("chainDB.ReadHeader(%q, %d) = %+v, want <nil>", want.Hash().String(), want.Number.Uint64(), got)
+			}
+
+			wrapper.writer.WriteHeader(want)
+			if err := wrapper.done(); err != nil {
+				t.Fatalf("wrapper.done() = %v, want <nil>", err)
+			}
+
+			if present := chainDB.HasHeader(want.Hash(), want.Number.Uint64()); !present {
+				t.Fatalf("chainDB.HasHeader(%q, %d) = false, want true", want.Hash().String(), want.Number.Uint64())
+			}
+
+			got := chainDB.ReadHeader(want.Hash(), want.Number.Uint64())
+			if diff := cmp.Diff(want, got, cmpopts.IgnoreUnexported(big.Int{})); diff != "" {
+				t.Fatalf("chainDB.ReadHeader(%q, %d) headers differ (-want +got):\n%s", want.Hash().String(), want.Number.Uint64(), diff)
+			}
+
+			wrapper.writer.DeleteHeader(want.Hash(), want.Number.Uint64())
+			if err := wrapper.done(); err != nil {
+				t.Fatalf("wrapper.done() = %v, want <nil>", err)
+			}
+
+			if present := chainDB.HasHeader(want.Hash(), want.Number.Uint64()); present {
+				t.Fatalf("chainDB.HasHeader(%q, %d) = true, want false", want.Hash().String(), want.Number.Uint64())
+			}
+
+			if got := chainDB.ReadHeader(want.Hash(), want.Number.Uint64()); got != nil {
+				t.Fatalf("chainDB.ReadHeader(%q, %d) = %+v, want <nil>", want.Hash().String(), want.Number.Uint64(), got)
+			}
+		})
+	}
+}
+
+func TestChainDB_HasReadWriteDeleteBody(t *testing.T) {
+	for _, tc := range tests {
+		tc := tc // Capture test case.
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			db := ethdb.NewMemDatabase()
+			chainDB := Wrap(db)
+			wrapper := tc.createWrapper(chainDB)
+
+			hash := common.HexToHash("0x1")
+			number := uint64(22)
+			tx := types.NewTransaction(1, common.HexToAddress("0x2"), big.NewInt(333), 4444, big.NewInt(55555), []byte{66, 66, 66})
+			want := &types.Body{Transactions: []*types.Transaction{tx}, Uncles: []*types.Header{{Number: big.NewInt(1), Difficulty: big.NewInt(2), Time: big.NewInt(3), Extra: []byte("test ommer header")}}}
+
+			if present := chainDB.HasBody(hash, number); present {
+				t.Fatalf("chainDB.HasBody(%q, %d) = true, want false", hash.String(), number)
+			}
+
+			if got := chainDB.ReadBody(hash, number); got != nil {
+				t.Fatalf("chainDB.ReadBody(%q, %d) = %+v, want <nil>", hash.String(), number, got)
+			}
+
+			wrapper.writer.WriteBody(hash, number, want)
+			if err := wrapper.done(); err != nil {
+				t.Fatalf("wrapper.done() = %v, want <nil>", err)
+			}
+
+			if present := chainDB.HasBody(hash, number); !present {
+				t.Fatalf("chainDB.HasBody(%q, %d) = false, want true", hash.String(), number)
+			}
+
+			got := chainDB.ReadBody(hash, number)
+			if diff := cmp.Diff(want, got, cmpopts.IgnoreUnexported(big.Int{}, types.Transaction{})); diff != "" {
+				t.Fatalf("chainDB.ReadBody(%q, %d) bodies differ (-want +got):\n%s", hash.String(), number, diff)
+			}
+
+			wrapper.writer.DeleteBody(hash, number)
+			if err := wrapper.done(); err != nil {
+				t.Fatalf("wrapper.done() = %v, want <nil>", err)
+			}
+
+			if present := chainDB.HasBody(hash, number); present {
+				t.Fatalf("chainDB.HasBody(%q, %d) = true, want false", hash, number)
+			}
+
+			if got := chainDB.ReadBody(hash, number); got != nil {
+				t.Fatalf("chainDB.ReadBody(%q, %d) = %+v, want <nil>", hash.String(), number, got)
+			}
+		})
+	}
+}
+
+func TestChainDB_ReadWriteDeleteBlock(t *testing.T) {
+	for _, tc := range tests {
+		tc := tc // Capture test case.
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			db := ethdb.NewMemDatabase()
+			chainDB := Wrap(db)
+			wrapper := tc.createWrapper(chainDB)
+
+			header := &types.Header{Number: big.NewInt(1), Difficulty: big.NewInt(2), Time: big.NewInt(3), Extra: []byte("test header")}
+			tx := types.NewTransaction(1, common.HexToAddress("0x2"), big.NewInt(333), 4444, big.NewInt(55555), []byte{66, 66, 66})
+			ommerHeader := &types.Header{Number: big.NewInt(4), Difficulty: big.NewInt(5), Time: big.NewInt(6), Extra: []byte("test ommer header")}
+			want := types.NewBlock(header, []*types.Transaction{tx}, []*types.Header{ommerHeader}, nil)
+
+			if got := chainDB.ReadBlock(want.Hash(), want.NumberU64()); got != nil {
+				t.Fatalf("chainDB.ReadBlock(%q, %d) = %+v, want <nil>", want.Hash().String(), want.NumberU64(), got)
+			}
+
+			wrapper.writer.WriteBlock(want)
+			if err := wrapper.done(); err != nil {
+				t.Fatalf("wrapper.done() = %v, want <nil>", err)
+			}
+
+			got := chainDB.ReadBlock(want.Hash(), want.NumberU64())
+			if diff := cmp.Diff(want, got, cmpopts.IgnoreUnexported(big.Int{}, types.Block{}, types.Transaction{})); diff != "" {
+				t.Fatalf("chainDB.ReadBlock(%q, %d) bodies differ (-want +got):\n%s", want.Hash().String(), want.NumberU64(), diff)
+			}
+
+			wrapper.writer.DeleteBlock(want.Hash(), want.NumberU64())
+			if err := wrapper.done(); err != nil {
+				t.Fatalf("wrapper.done() = %v, want <nil>", err)
+			}
+
+			if got := chainDB.ReadBlock(want.Hash(), want.NumberU64()); got != nil {
+				t.Fatalf("chainDB.ReadBlock(%q, %d) = %+v, want <nil>", want.Hash().String(), want.NumberU64(), got)
+			}
+		})
+	}
+}
+
+func TestChainDB_HasReadWriteDeleteReceipts(t *testing.T) {
+	for _, tc := range tests {
+		tc := tc // Capture test case.
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			db := ethdb.NewMemDatabase()
+			chainDB := Wrap(db)
+			wrapper := tc.createWrapper(chainDB)
+
+			hash := common.HexToHash("0x1")
+			number := uint64(22)
+			want := types.Receipts{types.NewReceipt(nil, false, 333)}
+
+			if present := chainDB.HasReceipts(hash, number); present {
+				t.Fatalf("chainDB.HasReceipts(%q, %d) = true, want false", hash.String(), number)
+			}
+
+			if got := chainDB.ReadReceipts(hash, number); got != nil {
+				t.Fatalf("chainDB.ReadReceipts(%q, %d) = %+v, want <nil>", hash.String(), number, got)
+			}
+
+			wrapper.writer.WriteReceipts(hash, number, want)
+			if err := wrapper.done(); err != nil {
+				t.Fatalf("wrapper.done() = %v, want <nil>", err)
+			}
+
+			if present := chainDB.HasReceipts(hash, number); !present {
+				t.Fatalf("chainDB.HasReceipts(%q, %d) = false, want true", hash.String(), number)
+			}
+
+			got := chainDB.ReadReceipts(hash, number)
+			if diff := cmp.Diff(want, got, cmpopts.EquateEmpty()); diff != "" {
+				t.Fatalf("chainDB.ReadReceipts(%q, %d) bodies differ (-want +got):\n%s", hash.String(), number, diff)
+			}
+
+			wrapper.writer.DeleteReceipts(hash, number)
+			if err := wrapper.done(); err != nil {
+				t.Fatalf("wrapper.done() = %v, want <nil>", err)
+			}
+
+			if present := chainDB.HasReceipts(hash, number); present {
+				t.Fatalf("chainDB.HasReceipts(%q, %d) = true, want false", hash, number)
+			}
+
+			if got := chainDB.ReadReceipts(hash, number); got != nil {
+				t.Fatalf("chainDB.ReadReceipts(%q, %d) = %+v, want <nil>", hash.String(), number, got)
+			}
+		})
+	}
+}
+
+func cmpBigInt(a, b *big.Int) bool {
+	fmt.Println("a", a)
+	fmt.Println("b", b)
+	return a.Cmp(b) == 0
+}
+
+func TestChainDB_ReadWriteDeleteTxLookupEntries(t *testing.T) {
+	for _, tc := range tests {
+		tc := tc // Capture test case.
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			db := ethdb.NewMemDatabase()
+			chainDB := Wrap(db)
+			wrapper := tc.createWrapper(chainDB)
+
+			header := &types.Header{}
+			tx := types.NewTransaction(1, common.HexToAddress("0x2"), big.NewInt(333), 4444, big.NewInt(55555), []byte{66, 66, 66})
+			txs := []*types.Transaction{tx}
+			block := types.NewBlock(header, txs, []*types.Header{}, nil)
+
+			if got := chainDB.ReadTxLookupEntry(tx.Hash()); got != (common.Hash{}) {
+				t.Fatalf("chainDB.ReadTxLookupEntry(%q) = %s, want %s", tx.Hash(), got.String(), (common.Hash{}).String())
+			}
+
+			if got, blockHash, blockNumber, txIndex := chainDB.ReadTransaction(tx.Hash()); got != nil {
+				t.Fatalf("chainDB.ReadTransaction(%q) = %+v, %s, %d, %d, want <nil>, %s, 0, 0", tx.Hash(), got, blockHash.String(), blockNumber, txIndex, tx.Hash().String())
+			}
+
+			// WriteBlock ensures the hash-to-number mapping and block bodies for transaction retrieval are present.
+			wrapper.writer.WriteBlock(block)
+			wrapper.writer.WriteTxLookupEntries(block)
+			if err := wrapper.done(); err != nil {
+				t.Fatalf("wrapper.done() = %v, want <nil>", err)
+			}
+
+			if got := chainDB.ReadTxLookupEntry(tx.Hash()); got != block.Hash() {
+				t.Fatalf("chainDB.ReadTxLookupEntry(%q) = %s, want %s", tx.Hash(), got.String(), block.Hash().String())
+			}
+
+			got, blockHash, blockNumber, txIndex := chainDB.ReadTransaction(tx.Hash())
+			if diff := cmp.Diff(tx, got, cmpopts.IgnoreUnexported(types.Transaction{})); diff != "" {
+				t.Fatalf("chainDB.ReadTransaction(%q) differ (-want +got):\n%s", tx.Hash().String(), diff)
+			}
+			if blockHash != block.Hash() || blockNumber != block.NumberU64() || txIndex != 0 {
+				t.Fatalf("chainDB.ReadTransaction(%q) = ..., %s, %d, %d, want ..., %s, %d, %d", tx.Hash().String(), blockHash.String(), blockNumber, txIndex, block.Hash().String(), block.NumberU64(), 0)
+			}
+
+			wrapper.writer.DeleteTxLookupEntry(tx.Hash())
+			if err := wrapper.done(); err != nil {
+				t.Fatalf("wrapper.done() = %v, want <nil>", err)
+			}
+
+			if got := chainDB.ReadTxLookupEntry(tx.Hash()); got != (common.Hash{}) {
+				t.Fatalf("chainDB.ReadTxLookupEntry(%q) = %s, want %s", tx.Hash(), got.String(), (common.Hash{}).String())
+			}
+
+			if got, blockHash, blockNumber, txIndex := chainDB.ReadTransaction(tx.Hash()); got != nil {
+				t.Fatalf("chainDB.ReadTransaction(%q) = %+v, %s, %d, %d, want <nil>, %s, 0, 0", tx.Hash(), got, blockHash.String(), blockNumber, txIndex, tx.Hash().String())
+			}
+		})
+	}
+}
+
+func TestChainDB_ReadWriteDeleteTD(t *testing.T) {
+	for _, tc := range tests {
+		tc := tc // Capture test case.
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			db := ethdb.NewMemDatabase()
+			chainDB := Wrap(db)
+			wrapper := tc.createWrapper(chainDB)
+
+			hash := common.HexToHash("0x1")
+			number := uint64(22)
+			want := big.NewInt(3333)
+
+			if got := chainDB.ReadTD(hash, number); got != nil {
+				t.Fatalf("chainDB.ReadTD(%q, %d) = %+v, want <nil>", hash.String(), number, got)
+			}
+
+			wrapper.writer.WriteTD(hash, number, want)
+			if err := wrapper.done(); err != nil {
+				t.Fatalf("wrapper.done() = %v, want <nil>", err)
+			}
+
+			if got := chainDB.ReadTD(hash, number); got == nil || got.Cmp(want) != 0 {
+				t.Fatalf("chainDB.ReadTD(%q, %d) = %+v, want %+v", hash.String(), number, got, want)
+			}
+
+			wrapper.writer.DeleteTD(hash, number)
+			if err := wrapper.done(); err != nil {
+				t.Fatalf("wrapper.done() = %v, want <nil>", err)
+			}
+
+			if got := chainDB.ReadTD(hash, number); got != nil {
+				t.Fatalf("chainDB.ReadTD(%q, %d) = %+v, want <nil>", hash.String(), number, got)
+			}
+		})
+	}
+}
+
+func TestChainDB_ReadWritePreimages(t *testing.T) {
+	for _, tc := range tests {
+		tc := tc // Capture test case.
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			db := ethdb.NewMemDatabase()
+			chainDB := Wrap(db)
+			wrapper := tc.createWrapper(chainDB)
+
+			preimages := map[common.Hash][]byte{
+				common.HexToHash("0x1"): common.Hex2Bytes("0xa"),
+				common.HexToHash("0x2"): common.Hex2Bytes("0xb"),
+				common.HexToHash("0x3"): common.Hex2Bytes("0xc"),
+			}
+
+			for preimage := range preimages {
+				if got := chainDB.ReadPreimage(preimage); got != nil {
+					t.Fatalf("chainDB.ReadPreimage(%q) = %s, want <nil>", preimage, hex.EncodeToString(got))
+				}
+			}
+
+			wrapper.writer.WritePreimages(preimages)
+			if err := wrapper.done(); err != nil {
+				t.Fatalf("wrapper.done() = %v, want <nil>", err)
+			}
+
+			for preimage, want := range preimages {
+				if got := chainDB.ReadPreimage(preimage); !bytes.Equal(got, want) {
+					t.Fatalf("chainDB.ReadPreimage(%q) = %s, want %s", preimage, hex.EncodeToString(got), hex.EncodeToString(want))
+				}
+			}
+		})
+	}
+}

core/headerchain.go

@@ -28,9 +28,8 @@ import (
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/consensus"
-	"github.com/ethereum/go-ethereum/core/rawdb"
+	"github.com/ethereum/go-ethereum/core/chaindb"
 	"github.com/ethereum/go-ethereum/core/types"
-	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/params"
 	"github.com/hashicorp/golang-lru"
@@ -50,7 +49,7 @@ const (
 type HeaderChain struct {
 	config *params.ChainConfig
 
-	chainDb       ethdb.Database
+	chainDB       *chaindb.ChainDB
 	genesisHeader *types.Header
 
 	currentHeader     atomic.Value // Current head of the header chain (may be above the block chain!)
@@ -70,7 +69,7 @@ type HeaderChain struct {
 //  getValidator should return the parent's validator
 //  procInterrupt points to the parent's interrupt semaphore
 //  wg points to the parent's shutdown wait group
-func NewHeaderChain(chainDb ethdb.Database, config *params.ChainConfig, engine consensus.Engine, procInterrupt func() bool) (*HeaderChain, error) {
+func NewHeaderChain(chainDB *chaindb.ChainDB, config *params.ChainConfig, engine consensus.Engine, procInterrupt func() bool) (*HeaderChain, error) {
 	headerCache, _ := lru.New(headerCacheLimit)
 	tdCache, _ := lru.New(tdCacheLimit)
 	numberCache, _ := lru.New(numberCacheLimit)
@@ -83,7 +82,7 @@ func NewHeaderChain(chainDb ethdb.Database, config *params.ChainConfig, engine c
 
 	hc := &HeaderChain{
 		config:        config,
-		chainDb:       chainDb,
+		chainDB:       chainDB,
 		headerCache:   headerCache,
 		tdCache:       tdCache,
 		numberCache:   numberCache,
@@ -98,7 +97,7 @@ func NewHeaderChain(chainDb ethdb.Database, config *params.ChainConfig, engine c
 	}
 
 	hc.currentHeader.Store(hc.genesisHeader)
-	if head := rawdb.ReadHeadBlockHash(chainDb); head != (common.Hash{}) {
+	if head := hc.chainDB.ReadHeadBlockHash(); head != (common.Hash{}) {
 		if chead := hc.GetHeaderByHash(head); chead != nil {
 			hc.currentHeader.Store(chead)
 		}
@@ -115,7 +114,7 @@ func (hc *HeaderChain) GetBlockNumber(hash common.Hash) *uint64 {
 		number := cached.(uint64)
 		return &number
 	}
-	number := rawdb.ReadHeaderNumber(hc.chainDb, hash)
+	number := hc.chainDB.ReadHeaderNumber(hash)
 	if number != nil {
 		hc.numberCache.Add(hash, *number)
 	}
@@ -149,20 +148,20 @@ func (hc *HeaderChain) WriteHeader(header *types.Header) (status WriteStatus, er
 	if err := hc.WriteTd(hash, number, externTd); err != nil {
 		log.Crit("Failed to write header total difficulty", "err", err)
 	}
-	rawdb.WriteHeader(hc.chainDb, header)
+	hc.chainDB.WriteHeader(header)
 
 	// If the total difficulty is higher than our known, add it to the canonical chain
 	// Second clause in the if statement reduces the vulnerability to selfish mining.
 	// Please refer to http://www.cs.cornell.edu/~ie53/publications/btcProcFC.pdf
 	if externTd.Cmp(localTd) > 0 || (externTd.Cmp(localTd) == 0 && mrand.Float64() < 0.5) {
 		// Delete any canonical number assignments above the new head
-		batch := hc.chainDb.NewBatch()
+		batch := hc.chainDB.NewBatch()
 		for i := number + 1; ; i++ {
-			hash := rawdb.ReadCanonicalHash(hc.chainDb, i)
+			hash := hc.chainDB.ReadCanonicalHash(i)
 			if hash == (common.Hash{}) {
 				break
 			}
-			rawdb.DeleteCanonicalHash(batch, i)
+			batch.DeleteCanonicalHash(i)
 		}
 		batch.Write()
 
@@ -172,16 +171,16 @@ func (hc *HeaderChain) WriteHeader(header *types.Header) (status WriteStatus, er
 			headNumber = header.Number.Uint64() - 1
 			headHeader = hc.GetHeader(headHash, headNumber)
 		)
-		for rawdb.ReadCanonicalHash(hc.chainDb, headNumber) != headHash {
+		for hc.chainDB.ReadCanonicalHash(headNumber) != headHash {
-			rawdb.WriteCanonicalHash(hc.chainDb, headHash, headNumber)
+			hc.chainDB.WriteCanonicalHash(headNumber, headHash)
 
 			headHash = headHeader.ParentHash
 			headNumber = headHeader.Number.Uint64() - 1
 			headHeader = hc.GetHeader(headHash, headNumber)
 		}
 		// Extend the canonical chain with the new header
-		rawdb.WriteCanonicalHash(hc.chainDb, hash, number)
+		hc.chainDB.WriteCanonicalHash(number, hash)
-		rawdb.WriteHeadHeaderHash(hc.chainDb, hash)
+		hc.chainDB.WriteHeadHeaderHash(hash)
 
 		hc.currentHeaderHash = hash
 		hc.currentHeader.Store(types.CopyHeader(header))
@@ -342,9 +341,9 @@ func (hc *HeaderChain) GetAncestor(hash common.Hash, number, ancestor uint64, ma
 		}
 	}
 	for ancestor != 0 {
-		if rawdb.ReadCanonicalHash(hc.chainDb, number) == hash {
+		if hc.chainDB.ReadCanonicalHash(number) == hash {
 			number -= ancestor
-			return rawdb.ReadCanonicalHash(hc.chainDb, number), number
+			return hc.chainDB.ReadCanonicalHash(number), number
 		}
 		if *maxNonCanonical == 0 {
 			return common.Hash{}, 0
@@ -368,7 +367,7 @@ func (hc *HeaderChain) GetTd(hash common.Hash, number uint64) *big.Int {
 	if cached, ok := hc.tdCache.Get(hash); ok {
 		return cached.(*big.Int)
 	}
-	td := rawdb.ReadTd(hc.chainDb, hash, number)
+	td := hc.chainDB.ReadTD(hash, number)
 	if td == nil {
 		return nil
 	}
@@ -390,7 +389,7 @@ func (hc *HeaderChain) GetTdByHash(hash common.Hash) *big.Int {
 // WriteTd stores a block's total difficulty into the database, also caching it
 // along the way.
 func (hc *HeaderChain) WriteTd(hash common.Hash, number uint64, td *big.Int) error {
-	rawdb.WriteTd(hc.chainDb, hash, number, td)
+	hc.chainDB.WriteTD(hash, number, td)
 	hc.tdCache.Add(hash, new(big.Int).Set(td))
 	return nil
 }
@@ -402,7 +401,7 @@ func (hc *HeaderChain) GetHeader(hash common.Hash, number uint64) *types.Header
 	if header, ok := hc.headerCache.Get(hash); ok {
 		return header.(*types.Header)
 	}
-	header := rawdb.ReadHeader(hc.chainDb, hash, number)
+	header := hc.chainDB.ReadHeader(hash, number)
 	if header == nil {
 		return nil
 	}
@@ -426,13 +425,13 @@ func (hc *HeaderChain) HasHeader(hash common.Hash, number uint64) bool {
 	if hc.numberCache.Contains(hash) || hc.headerCache.Contains(hash) {
 		return true
 	}
-	return rawdb.HasHeader(hc.chainDb, hash, number)
+	return hc.chainDB.HasHeader(hash, number)
 }
 
 // GetHeaderByNumber retrieves a block header from the database by number,
 // caching it (associated with its hash) if found.
 func (hc *HeaderChain) GetHeaderByNumber(number uint64) *types.Header {
-	hash := rawdb.ReadCanonicalHash(hc.chainDb, number)
+	hash := hc.chainDB.ReadCanonicalHash(number)
 	if hash == (common.Hash{}) {
 		return nil
 	}
@@ -447,7 +446,7 @@ func (hc *HeaderChain) CurrentHeader() *types.Header {
 
 // SetCurrentHeader sets the current head header of the canonical chain.
 func (hc *HeaderChain) SetCurrentHeader(head *types.Header) {
-	rawdb.WriteHeadHeaderHash(hc.chainDb, head.Hash())
+	hc.chainDB.WriteHeadHeaderHash(head.Hash())
 
 	hc.currentHeader.Store(head)
 	hc.currentHeaderHash = head.Hash()
@@ -455,7 +454,7 @@ func (hc *HeaderChain) SetCurrentHeader(head *types.Header) {
 
 // DeleteCallback is a callback function that is called by SetHead before
 // each header is deleted.
-type DeleteCallback func(rawdb.DatabaseDeleter, common.Hash, uint64)
+type DeleteCallback func(*chaindb.Batch, common.Hash, uint64)
 
 // SetHead rewinds the local chain to a new head. Everything above the new head
 // will be deleted and the new one set.
@@ -465,21 +464,21 @@ func (hc *HeaderChain) SetHead(head uint64, delFn DeleteCallback) {
 	if hdr := hc.CurrentHeader(); hdr != nil {
 		height = hdr.Number.Uint64()
 	}
-	batch := hc.chainDb.NewBatch()
+	batch := hc.chainDB.NewBatch()
 	for hdr := hc.CurrentHeader(); hdr != nil && hdr.Number.Uint64() > head; hdr = hc.CurrentHeader() {
 		hash := hdr.Hash()
 		num := hdr.Number.Uint64()
 		if delFn != nil {
 			delFn(batch, hash, num)
 		}
-		rawdb.DeleteHeader(batch, hash, num)
+		batch.DeleteHeader(hash, num)
-		rawdb.DeleteTd(batch, hash, num)
+		batch.DeleteTD(hash, num)
 
 		hc.currentHeader.Store(hc.GetHeader(hdr.ParentHash, hdr.Number.Uint64()-1))
 	}
 	// Roll back the canonical chain numbering
 	for i := height; i > head; i-- {
-		rawdb.DeleteCanonicalHash(batch, i)
+		batch.DeleteCanonicalHash(i)
 	}
 	batch.Write()
 
@@ -493,7 +492,7 @@ func (hc *HeaderChain) SetHead(head uint64, delFn DeleteCallback) {
 	}
 	hc.currentHeaderHash = hc.CurrentHeader().Hash()
 
-	rawdb.WriteHeadHeaderHash(hc.chainDb, hc.currentHeaderHash)
+	hc.chainDB.WriteHeadHeaderHash(hc.currentHeaderHash)
 }
 
 // SetGenesis sets a new genesis block header for the chain

core/rawdb/accessors_chain.go

@@ -60,6 +60,14 @@ func ReadHeaderNumber(db DatabaseReader, hash common.Hash) *uint64 {
 	return &number
 }
 
+// WriteHeaderNumber stores the header number assigned to a hash.
+func WriteHeaderNumber(db DatabaseWriter, hash common.Hash, number uint64) {
+	key := headerNumberKey(hash)
+	if err := db.Put(key, encodeBlockNumber(number)); err != nil {
+		log.Crit("Failed to store hash to number mapping", "err", err)
+	}
+}
+
 // ReadHeadHeaderHash retrieves the hash of the current canonical head header.
 func ReadHeadHeaderHash(db DatabaseReader) common.Hash {
 	data, _ := db.Get(headHeaderKey)
@@ -161,18 +169,14 @@ func WriteHeader(db DatabaseWriter, header *types.Header) {
 	var (
 		hash   = header.Hash()
 		number = header.Number.Uint64()
-		encoded = encodeBlockNumber(number)
 	)
-	key := headerNumberKey(hash)
+	WriteHeaderNumber(db, hash, number)
-	if err := db.Put(key, encoded); err != nil {
-		log.Crit("Failed to store hash to number mapping", "err", err)
-	}
 	// Write the encoded header
 	data, err := rlp.EncodeToBytes(header)
 	if err != nil {
 		log.Crit("Failed to RLP encode header", "err", err)
 	}
-	key = headerKey(number, hash)
+	key := headerKey(number, hash)
 	if err := db.Put(key, data); err != nil {
 		log.Crit("Failed to store header", "err", err)
 	}

core/rawdb/accessors_indexes.go

@@ -64,20 +64,24 @@ func ReadTransaction(db DatabaseReader, hash common.Hash) (*types.Transaction, c
 	if blockHash == (common.Hash{}) {
 		return nil, common.Hash{}, 0, 0
 	}
+
 	blockNumber := ReadHeaderNumber(db, blockHash)
 	if blockNumber == nil {
 		return nil, common.Hash{}, 0, 0
 	}
+
 	body := ReadBody(db, blockHash, *blockNumber)
 	if body == nil {
 		log.Error("Transaction referenced missing", "number", blockNumber, "hash", blockHash)
 		return nil, common.Hash{}, 0, 0
 	}
+
 	for txIndex, tx := range body.Transactions {
 		if tx.Hash() == hash {
 			return tx, blockHash, *blockNumber, uint64(txIndex)
 		}
 	}
+
 	log.Error("Transaction not found", "number", blockNumber, "hash", blockHash, "txhash", hash)
 	return nil, common.Hash{}, 0, 0
 }

light/lightchain.go

@@ -29,7 +29,7 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/consensus"
 	"github.com/ethereum/go-ethereum/core"
-	"github.com/ethereum/go-ethereum/core/rawdb"
+	"github.com/ethereum/go-ethereum/core/chaindb"
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/ethdb"
@@ -51,7 +51,8 @@ var (
 type LightChain struct {
 	hc            *core.HeaderChain
 	indexerConfig *IndexerConfig
-	chainDb       ethdb.Database
+	db            ethdb.Database
+	chainDB       *chaindb.ChainDB
 	engine        consensus.Engine
 	odr           OdrBackend
 	chainFeed     event.Feed
@@ -82,8 +83,11 @@ func NewLightChain(odr OdrBackend, config *params.ChainConfig, engine consensus.
 	bodyRLPCache, _ := lru.New(bodyCacheLimit)
 	blockCache, _ := lru.New(blockCacheLimit)
 
+	db := odr.Database()
+	chainDB := chaindb.Wrap(db)
 	bc := &LightChain{
-		chainDb:       odr.Database(),
+		db:            db,
+		chainDB:       chainDB,
 		indexerConfig: odr.IndexerConfig(),
 		odr:           odr,
 		quit:          make(chan struct{}),
@@ -93,7 +97,7 @@ func NewLightChain(odr OdrBackend, config *params.ChainConfig, engine consensus.
 		engine:        engine,
 	}
 	var err error
-	bc.hc, err = core.NewHeaderChain(odr.Database(), config, bc.engine, bc.getProcInterrupt)
+	bc.hc, err = core.NewHeaderChain(chainDB, config, bc.engine, bc.getProcInterrupt)
 	if err != nil {
 		return nil, err
 	}
@@ -121,11 +125,11 @@ func NewLightChain(odr OdrBackend, config *params.ChainConfig, engine consensus.
 // addTrustedCheckpoint adds a trusted checkpoint to the blockchain
 func (lc *LightChain) addTrustedCheckpoint(cp *params.TrustedCheckpoint) {
 	if lc.odr.ChtIndexer() != nil {
-		StoreChtRoot(lc.chainDb, cp.SectionIndex, cp.SectionHead, cp.CHTRoot)
+		StoreChtRoot(lc.db, cp.SectionIndex, cp.SectionHead, cp.CHTRoot)
 		lc.odr.ChtIndexer().AddCheckpoint(cp.SectionIndex, cp.SectionHead)
 	}
 	if lc.odr.BloomTrieIndexer() != nil {
-		StoreBloomTrieRoot(lc.chainDb, cp.SectionIndex, cp.SectionHead, cp.BloomRoot)
+		StoreBloomTrieRoot(lc.db, cp.SectionIndex, cp.SectionHead, cp.BloomRoot)
 		lc.odr.BloomTrieIndexer().AddCheckpoint(cp.SectionIndex, cp.SectionHead)
 	}
 	if lc.odr.BloomIndexer() != nil {
@@ -146,7 +150,7 @@ func (lc *LightChain) Odr() OdrBackend {
 // loadLastState loads the last known chain state from the database. This method
 // assumes that the chain manager mutex is held.
 func (lc *LightChain) loadLastState() error {
-	if head := rawdb.ReadHeadHeaderHash(lc.chainDb); head == (common.Hash{}) {
+	if head := lc.chainDB.ReadHeadHeaderHash(); head == (common.Hash{}) {
 		// Corrupt or empty database, init from scratch
 		lc.Reset()
 	} else {
@@ -193,8 +197,8 @@ func (lc *LightChain) ResetWithGenesisBlock(genesis *types.Block) {
 	defer lc.chainmu.Unlock()
 
 	// Prepare the genesis block and reinitialise the chain
-	rawdb.WriteTd(lc.chainDb, genesis.Hash(), genesis.NumberU64(), genesis.Difficulty())
+	lc.chainDB.WriteTD(genesis.Hash(), genesis.NumberU64(), genesis.Difficulty())
-	rawdb.WriteBlock(lc.chainDb, genesis)
+	lc.chainDB.WriteBlock(genesis)
 
 	lc.genesisBlock = genesis
 	lc.hc.SetGenesis(lc.genesisBlock.Header())

light/lightchain_test.go

@@ -123,8 +123,8 @@ func testHeaderChainImport(chain []*types.Header, lightchain *LightChain) error
 		}
 		// Manually insert the header into the database, but don't reorganize (allows subsequent testing)
 		lightchain.chainmu.Lock()
-		rawdb.WriteTd(lightchain.chainDb, header.Hash(), header.Number.Uint64(), new(big.Int).Add(header.Difficulty, lightchain.GetTdByHash(header.ParentHash)))
+		rawdb.WriteTd(lightchain.db, header.Hash(), header.Number.Uint64(), new(big.Int).Add(header.Difficulty, lightchain.GetTdByHash(header.ParentHash)))
-		rawdb.WriteHeader(lightchain.chainDb, header)
+		rawdb.WriteHeader(lightchain.db, header)
 		lightchain.chainmu.Unlock()
 	}
 	return nil
@@ -344,7 +344,7 @@ func TestReorgBadHeaderHashes(t *testing.T) {
 	defer func() { delete(core.BadHashes, headers[3].Hash()) }()
 
 	// Create a new LightChain and check that it rolled back the state.
-	ncm, err := NewLightChain(&dummyOdr{db: bc.chainDb}, params.TestChainConfig, ethash.NewFaker())
+	ncm, err := NewLightChain(&dummyOdr{db: bc.db}, params.TestChainConfig, ethash.NewFaker())
 	if err != nil {
 		t.Fatalf("failed to create new chain manager: %v", err)
 	}

vendor/github.com/google/go-cmp/LICENSE

@@ -0,0 +1,27 @@
+Copyright (c) 2017 The Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/github.com/google/go-cmp/cmp/cmpopts/equate.go

@@ -0,0 +1,89 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+// Package cmpopts provides common options for the cmp package.
+package cmpopts
+
+import (
+	"math"
+	"reflect"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+func equateAlways(_, _ interface{}) bool { return true }
+
+// EquateEmpty returns a Comparer option that determines all maps and slices
+// with a length of zero to be equal, regardless of whether they are nil.
+//
+// EquateEmpty can be used in conjunction with SortSlices and SortMaps.
+func EquateEmpty() cmp.Option {
+	return cmp.FilterValues(isEmpty, cmp.Comparer(equateAlways))
+}
+
+func isEmpty(x, y interface{}) bool {
+	vx, vy := reflect.ValueOf(x), reflect.ValueOf(y)
+	return (x != nil && y != nil && vx.Type() == vy.Type()) &&
+		(vx.Kind() == reflect.Slice || vx.Kind() == reflect.Map) &&
+		(vx.Len() == 0 && vy.Len() == 0)
+}
+
+// EquateApprox returns a Comparer option that determines float32 or float64
+// values to be equal if they are within a relative fraction or absolute margin.
+// This option is not used when either x or y is NaN or infinite.
+//
+// The fraction determines that the difference of two values must be within the
+// smaller fraction of the two values, while the margin determines that the two
+// values must be within some absolute margin.
+// To express only a fraction or only a margin, use 0 for the other parameter.
+// The fraction and margin must be non-negative.
+//
+// The mathematical expression used is equivalent to:
+//	|x-y| ≤ max(fraction*min(|x|, |y|), margin)
+//
+// EquateApprox can be used in conjunction with EquateNaNs.
+func EquateApprox(fraction, margin float64) cmp.Option {
+	if margin < 0 || fraction < 0 || math.IsNaN(margin) || math.IsNaN(fraction) {
+		panic("margin or fraction must be a non-negative number")
+	}
+	a := approximator{fraction, margin}
+	return cmp.Options{
+		cmp.FilterValues(areRealF64s, cmp.Comparer(a.compareF64)),
+		cmp.FilterValues(areRealF32s, cmp.Comparer(a.compareF32)),
+	}
+}
+
+type approximator struct{ frac, marg float64 }
+
+func areRealF64s(x, y float64) bool {
+	return !math.IsNaN(x) && !math.IsNaN(y) && !math.IsInf(x, 0) && !math.IsInf(y, 0)
+}
+func areRealF32s(x, y float32) bool {
+	return areRealF64s(float64(x), float64(y))
+}
+func (a approximator) compareF64(x, y float64) bool {
+	relMarg := a.frac * math.Min(math.Abs(x), math.Abs(y))
+	return math.Abs(x-y) <= math.Max(a.marg, relMarg)
+}
+func (a approximator) compareF32(x, y float32) bool {
+	return a.compareF64(float64(x), float64(y))
+}
+
+// EquateNaNs returns a Comparer option that determines float32 and float64
+// NaN values to be equal.
+//
+// EquateNaNs can be used in conjunction with EquateApprox.
+func EquateNaNs() cmp.Option {
+	return cmp.Options{
+		cmp.FilterValues(areNaNsF64s, cmp.Comparer(equateAlways)),
+		cmp.FilterValues(areNaNsF32s, cmp.Comparer(equateAlways)),
+	}
+}
+
+func areNaNsF64s(x, y float64) bool {
+	return math.IsNaN(x) && math.IsNaN(y)
+}
+func areNaNsF32s(x, y float32) bool {
+	return areNaNsF64s(float64(x), float64(y))
+}

vendor/github.com/google/go-cmp/cmp/cmpopts/ignore.go

@@ -0,0 +1,149 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+package cmpopts
+
+import (
+	"fmt"
+	"reflect"
+	"unicode"
+	"unicode/utf8"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+// IgnoreFields returns an Option that ignores exported fields of the
+// given names on a single struct type.
+// The struct type is specified by passing in a value of that type.
+//
+// The name may be a dot-delimited string (e.g., "Foo.Bar") to ignore a
+// specific sub-field that is embedded or nested within the parent struct.
+//
+// This does not handle unexported fields; use IgnoreUnexported instead.
+func IgnoreFields(typ interface{}, names ...string) cmp.Option {
+	sf := newStructFilter(typ, names...)
+	return cmp.FilterPath(sf.filter, cmp.Ignore())
+}
+
+// IgnoreTypes returns an Option that ignores all values assignable to
+// certain types, which are specified by passing in a value of each type.
+func IgnoreTypes(typs ...interface{}) cmp.Option {
+	tf := newTypeFilter(typs...)
+	return cmp.FilterPath(tf.filter, cmp.Ignore())
+}
+
+type typeFilter []reflect.Type
+
+func newTypeFilter(typs ...interface{}) (tf typeFilter) {
+	for _, typ := range typs {
+		t := reflect.TypeOf(typ)
+		if t == nil {
+			// This occurs if someone tries to pass in sync.Locker(nil)
+			panic("cannot determine type; consider using IgnoreInterfaces")
+		}
+		tf = append(tf, t)
+	}
+	return tf
+}
+func (tf typeFilter) filter(p cmp.Path) bool {
+	if len(p) < 1 {
+		return false
+	}
+	t := p.Last().Type()
+	for _, ti := range tf {
+		if t.AssignableTo(ti) {
+			return true
+		}
+	}
+	return false
+}
+
+// IgnoreInterfaces returns an Option that ignores all values or references of
+// values assignable to certain interface types. These interfaces are specified
+// by passing in an anonymous struct with the interface types embedded in it.
+// For example, to ignore sync.Locker, pass in struct{sync.Locker}{}.
+func IgnoreInterfaces(ifaces interface{}) cmp.Option {
+	tf := newIfaceFilter(ifaces)
+	return cmp.FilterPath(tf.filter, cmp.Ignore())
+}
+
+type ifaceFilter []reflect.Type
+
+func newIfaceFilter(ifaces interface{}) (tf ifaceFilter) {
+	t := reflect.TypeOf(ifaces)
+	if ifaces == nil || t.Name() != "" || t.Kind() != reflect.Struct {
+		panic("input must be an anonymous struct")
+	}
+	for i := 0; i < t.NumField(); i++ {
+		fi := t.Field(i)
+		switch {
+		case !fi.Anonymous:
+			panic("struct cannot have named fields")
+		case fi.Type.Kind() != reflect.Interface:
+			panic("embedded field must be an interface type")
+		case fi.Type.NumMethod() == 0:
+			// This matches everything; why would you ever want this?
+			panic("cannot ignore empty interface")
+		default:
+			tf = append(tf, fi.Type)
+		}
+	}
+	return tf
+}
+func (tf ifaceFilter) filter(p cmp.Path) bool {
+	if len(p) < 1 {
+		return false
+	}
+	t := p.Last().Type()
+	for _, ti := range tf {
+		if t.AssignableTo(ti) {
+			return true
+		}
+		if t.Kind() != reflect.Ptr && reflect.PtrTo(t).AssignableTo(ti) {
+			return true
+		}
+	}
+	return false
+}
+
+// IgnoreUnexported returns an Option that only ignores the immediate unexported
+// fields of a struct, including anonymous fields of unexported types.
+// In particular, unexported fields within the struct's exported fields
+// of struct types, including anonymous fields, will not be ignored unless the
+// type of the field itself is also passed to IgnoreUnexported.
+//
+// Avoid ignoring unexported fields of a type which you do not control (i.e. a
+// type from another repository), as changes to the implementation of such types
+// may change how the comparison behaves. Prefer a custom Comparer instead.
+func IgnoreUnexported(typs ...interface{}) cmp.Option {
+	ux := newUnexportedFilter(typs...)
+	return cmp.FilterPath(ux.filter, cmp.Ignore())
+}
+
+type unexportedFilter struct{ m map[reflect.Type]bool }
+
+func newUnexportedFilter(typs ...interface{}) unexportedFilter {
+	ux := unexportedFilter{m: make(map[reflect.Type]bool)}
+	for _, typ := range typs {
+		t := reflect.TypeOf(typ)
+		if t == nil || t.Kind() != reflect.Struct {
+			panic(fmt.Sprintf("invalid struct type: %T", typ))
+		}
+		ux.m[t] = true
+	}
+	return ux
+}
+func (xf unexportedFilter) filter(p cmp.Path) bool {
+	sf, ok := p.Index(-1).(cmp.StructField)
+	if !ok {
+		return false
+	}
+	return xf.m[p.Index(-2).Type()] && !isExported(sf.Name())
+}
+
+// isExported reports whether the identifier is exported.
+func isExported(id string) bool {
+	r, _ := utf8.DecodeRuneInString(id)
+	return unicode.IsUpper(r)
+}

vendor/github.com/google/go-cmp/cmp/cmpopts/sort.go

@@ -0,0 +1,147 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+package cmpopts
+
+import (
+	"fmt"
+	"reflect"
+	"sort"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/internal/function"
+)
+
+// SortSlices returns a Transformer option that sorts all []V.
+// The less function must be of the form "func(T, T) bool" which is used to
+// sort any slice with element type V that is assignable to T.
+//
+// The less function must be:
+//	• Deterministic: less(x, y) == less(x, y)
+//	• Irreflexive: !less(x, x)
+//	• Transitive: if !less(x, y) and !less(y, z), then !less(x, z)
+//
+// The less function does not have to be "total". That is, if !less(x, y) and
+// !less(y, x) for two elements x and y, their relative order is maintained.
+//
+// SortSlices can be used in conjunction with EquateEmpty.
+func SortSlices(less interface{}) cmp.Option {
+	vf := reflect.ValueOf(less)
+	if !function.IsType(vf.Type(), function.Less) || vf.IsNil() {
+		panic(fmt.Sprintf("invalid less function: %T", less))
+	}
+	ss := sliceSorter{vf.Type().In(0), vf}
+	return cmp.FilterValues(ss.filter, cmp.Transformer("cmpopts.SortSlices", ss.sort))
+}
+
+type sliceSorter struct {
+	in  reflect.Type  // T
+	fnc reflect.Value // func(T, T) bool
+}
+
+func (ss sliceSorter) filter(x, y interface{}) bool {
+	vx, vy := reflect.ValueOf(x), reflect.ValueOf(y)
+	if !(x != nil && y != nil && vx.Type() == vy.Type()) ||
+		!(vx.Kind() == reflect.Slice && vx.Type().Elem().AssignableTo(ss.in)) ||
+		(vx.Len() <= 1 && vy.Len() <= 1) {
+		return false
+	}
+	// Check whether the slices are already sorted to avoid an infinite
+	// recursion cycle applying the same transform to itself.
+	ok1 := sort.SliceIsSorted(x, func(i, j int) bool { return ss.less(vx, i, j) })
+	ok2 := sort.SliceIsSorted(y, func(i, j int) bool { return ss.less(vy, i, j) })
+	return !ok1 || !ok2
+}
+func (ss sliceSorter) sort(x interface{}) interface{} {
+	src := reflect.ValueOf(x)
+	dst := reflect.MakeSlice(src.Type(), src.Len(), src.Len())
+	for i := 0; i < src.Len(); i++ {
+		dst.Index(i).Set(src.Index(i))
+	}
+	sort.SliceStable(dst.Interface(), func(i, j int) bool { return ss.less(dst, i, j) })
+	ss.checkSort(dst)
+	return dst.Interface()
+}
+func (ss sliceSorter) checkSort(v reflect.Value) {
+	start := -1 // Start of a sequence of equal elements.
+	for i := 1; i < v.Len(); i++ {
+		if ss.less(v, i-1, i) {
+			// Check that first and last elements in v[start:i] are equal.
+			if start >= 0 && (ss.less(v, start, i-1) || ss.less(v, i-1, start)) {
+				panic(fmt.Sprintf("incomparable values detected: want equal elements: %v", v.Slice(start, i)))
+			}
+			start = -1
+		} else if start == -1 {
+			start = i
+		}
+	}
+}
+func (ss sliceSorter) less(v reflect.Value, i, j int) bool {
+	vx, vy := v.Index(i), v.Index(j)
+	return ss.fnc.Call([]reflect.Value{vx, vy})[0].Bool()
+}
+
+// SortMaps returns a Transformer option that flattens map[K]V types to be a
+// sorted []struct{K, V}. The less function must be of the form
+// "func(T, T) bool" which is used to sort any map with key K that is
+// assignable to T.
+//
+// Flattening the map into a slice has the property that cmp.Equal is able to
+// use Comparers on K or the K.Equal method if it exists.
+//
+// The less function must be:
+//	• Deterministic: less(x, y) == less(x, y)
+//	• Irreflexive: !less(x, x)
+//	• Transitive: if !less(x, y) and !less(y, z), then !less(x, z)
+//	• Total: if x != y, then either less(x, y) or less(y, x)
+//
+// SortMaps can be used in conjunction with EquateEmpty.
+func SortMaps(less interface{}) cmp.Option {
+	vf := reflect.ValueOf(less)
+	if !function.IsType(vf.Type(), function.Less) || vf.IsNil() {
+		panic(fmt.Sprintf("invalid less function: %T", less))
+	}
+	ms := mapSorter{vf.Type().In(0), vf}
+	return cmp.FilterValues(ms.filter, cmp.Transformer("cmpopts.SortMaps", ms.sort))
+}
+
+type mapSorter struct {
+	in  reflect.Type  // T
+	fnc reflect.Value // func(T, T) bool
+}
+
+func (ms mapSorter) filter(x, y interface{}) bool {
+	vx, vy := reflect.ValueOf(x), reflect.ValueOf(y)
+	return (x != nil && y != nil && vx.Type() == vy.Type()) &&
+		(vx.Kind() == reflect.Map && vx.Type().Key().AssignableTo(ms.in)) &&
+		(vx.Len() != 0 || vy.Len() != 0)
+}
+func (ms mapSorter) sort(x interface{}) interface{} {
+	src := reflect.ValueOf(x)
+	outType := reflect.StructOf([]reflect.StructField{
+		{Name: "K", Type: src.Type().Key()},
+		{Name: "V", Type: src.Type().Elem()},
+	})
+	dst := reflect.MakeSlice(reflect.SliceOf(outType), src.Len(), src.Len())
+	for i, k := range src.MapKeys() {
+		v := reflect.New(outType).Elem()
+		v.Field(0).Set(k)
+		v.Field(1).Set(src.MapIndex(k))
+		dst.Index(i).Set(v)
+	}
+	sort.Slice(dst.Interface(), func(i, j int) bool { return ms.less(dst, i, j) })
+	ms.checkSort(dst)
+	return dst.Interface()
+}
+func (ms mapSorter) checkSort(v reflect.Value) {
+	for i := 1; i < v.Len(); i++ {
+		if !ms.less(v, i-1, i) {
+			panic(fmt.Sprintf("partial order detected: want %v < %v", v.Index(i-1), v.Index(i)))
+		}
+	}
+}
+func (ms mapSorter) less(v reflect.Value, i, j int) bool {
+	vx, vy := v.Index(i).Field(0), v.Index(j).Field(0)
+	return ms.fnc.Call([]reflect.Value{vx, vy})[0].Bool()
+}

vendor/github.com/google/go-cmp/cmp/cmpopts/struct_filter.go

@@ -0,0 +1,182 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+package cmpopts
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+// filterField returns a new Option where opt is only evaluated on paths that
+// include a specific exported field on a single struct type.
+// The struct type is specified by passing in a value of that type.
+//
+// The name may be a dot-delimited string (e.g., "Foo.Bar") to select a
+// specific sub-field that is embedded or nested within the parent struct.
+func filterField(typ interface{}, name string, opt cmp.Option) cmp.Option {
+	// TODO: This is currently unexported over concerns of how helper filters
+	// can be composed together easily.
+	// TODO: Add tests for FilterField.
+
+	sf := newStructFilter(typ, name)
+	return cmp.FilterPath(sf.filter, opt)
+}
+
+type structFilter struct {
+	t  reflect.Type // The root struct type to match on
+	ft fieldTree    // Tree of fields to match on
+}
+
+func newStructFilter(typ interface{}, names ...string) structFilter {
+	// TODO: Perhaps allow * as a special identifier to allow ignoring any
+	// number of path steps until the next field match?
+	// This could be useful when a concrete struct gets transformed into
+	// an anonymous struct where it is not possible to specify that by type,
+	// but the transformer happens to provide guarantees about the names of
+	// the transformed fields.
+
+	t := reflect.TypeOf(typ)
+	if t == nil || t.Kind() != reflect.Struct {
+		panic(fmt.Sprintf("%T must be a struct", typ))
+	}
+	var ft fieldTree
+	for _, name := range names {
+		cname, err := canonicalName(t, name)
+		if err != nil {
+			panic(fmt.Sprintf("%s: %v", strings.Join(cname, "."), err))
+		}
+		ft.insert(cname)
+	}
+	return structFilter{t, ft}
+}
+
+func (sf structFilter) filter(p cmp.Path) bool {
+	for i, ps := range p {
+		if ps.Type().AssignableTo(sf.t) && sf.ft.matchPrefix(p[i+1:]) {
+			return true
+		}
+	}
+	return false
+}
+
+// fieldTree represents a set of dot-separated identifiers.
+//
+// For example, inserting the following selectors:
+//	Foo
+//	Foo.Bar.Baz
+//	Foo.Buzz
+//	Nuka.Cola.Quantum
+//
+// Results in a tree of the form:
+//	{sub: {
+//		"Foo": {ok: true, sub: {
+//			"Bar": {sub: {
+//				"Baz": {ok: true},
+//			}},
+//			"Buzz": {ok: true},
+//		}},
+//		"Nuka": {sub: {
+//			"Cola": {sub: {
+//				"Quantum": {ok: true},
+//			}},
+//		}},
+//	}}
+type fieldTree struct {
+	ok  bool                 // Whether this is a specified node
+	sub map[string]fieldTree // The sub-tree of fields under this node
+}
+
+// insert inserts a sequence of field accesses into the tree.
+func (ft *fieldTree) insert(cname []string) {
+	if ft.sub == nil {
+		ft.sub = make(map[string]fieldTree)
+	}
+	if len(cname) == 0 {
+		ft.ok = true
+		return
+	}
+	sub := ft.sub[cname[0]]
+	sub.insert(cname[1:])
+	ft.sub[cname[0]] = sub
+}
+
+// matchPrefix reports whether any selector in the fieldTree matches
+// the start of path p.
+func (ft fieldTree) matchPrefix(p cmp.Path) bool {
+	for _, ps := range p {
+		switch ps := ps.(type) {
+		case cmp.StructField:
+			ft = ft.sub[ps.Name()]
+			if ft.ok {
+				return true
+			}
+			if len(ft.sub) == 0 {
+				return false
+			}
+		case cmp.Indirect:
+		default:
+			return false
+		}
+	}
+	return false
+}
+
+// canonicalName returns a list of identifiers where any struct field access
+// through an embedded field is expanded to include the names of the embedded
+// types themselves.
+//
+// For example, suppose field "Foo" is not directly in the parent struct,
+// but actually from an embedded struct of type "Bar". Then, the canonical name
+// of "Foo" is actually "Bar.Foo".
+//
+// Suppose field "Foo" is not directly in the parent struct, but actually
+// a field in two different embedded structs of types "Bar" and "Baz".
+// Then the selector "Foo" causes a panic since it is ambiguous which one it
+// refers to. The user must specify either "Bar.Foo" or "Baz.Foo".
+func canonicalName(t reflect.Type, sel string) ([]string, error) {
+	var name string
+	sel = strings.TrimPrefix(sel, ".")
+	if sel == "" {
+		return nil, fmt.Errorf("name must not be empty")
+	}
+	if i := strings.IndexByte(sel, '.'); i < 0 {
+		name, sel = sel, ""
+	} else {
+		name, sel = sel[:i], sel[i:]
+	}
+
+	// Type must be a struct or pointer to struct.
+	if t.Kind() == reflect.Ptr {
+		t = t.Elem()
+	}
+	if t.Kind() != reflect.Struct {
+		return nil, fmt.Errorf("%v must be a struct", t)
+	}
+
+	// Find the canonical name for this current field name.
+	// If the field exists in an embedded struct, then it will be expanded.
+	if !isExported(name) {
+		// Disallow unexported fields:
+		//	* To discourage people from actually touching unexported fields
+		//	* FieldByName is buggy (https://golang.org/issue/4876)
+		return []string{name}, fmt.Errorf("name must be exported")
+	}
+	sf, ok := t.FieldByName(name)
+	if !ok {
+		return []string{name}, fmt.Errorf("does not exist")
+	}
+	var ss []string
+	for i := range sf.Index {
+		ss = append(ss, t.FieldByIndex(sf.Index[:i+1]).Name)
+	}
+	if sel == "" {
+		return ss, nil
+	}
+	ssPost, err := canonicalName(sf.Type, sel)
+	return append(ss, ssPost...), err
+}

vendor/github.com/google/go-cmp/cmp/cmpopts/xform.go

@@ -0,0 +1,35 @@
+// Copyright 2018, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+package cmpopts
+
+import (
+	"github.com/google/go-cmp/cmp"
+)
+
+type xformFilter struct{ xform cmp.Option }
+
+func (xf xformFilter) filter(p cmp.Path) bool {
+	for _, ps := range p {
+		if t, ok := ps.(cmp.Transform); ok && t.Option() == xf.xform {
+			return false
+		}
+	}
+	return true
+}
+
+// AcyclicTransformer returns a Transformer with a filter applied that ensures
+// that the transformer cannot be recursively applied upon its own output.
+//
+// An example use case is a transformer that splits a string by lines:
+//	AcyclicTransformer("SplitLines", func(s string) []string{
+//		return strings.Split(s, "\n")
+//	})
+//
+// Had this been an unfiltered Transformer instead, this would result in an
+// infinite cycle converting a string to []string to [][]string and so on.
+func AcyclicTransformer(name string, f interface{}) cmp.Option {
+	xf := xformFilter{cmp.Transformer(name, f)}
+	return cmp.FilterPath(xf.filter, xf.xform)
+}

vendor/github.com/google/go-cmp/cmp/compare.go

@@ -0,0 +1,612 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+// Package cmp determines equality of values.
+//
+// This package is intended to be a more powerful and safer alternative to
+// reflect.DeepEqual for comparing whether two values are semantically equal.
+//
+// The primary features of cmp are:
+//
+// • When the default behavior of equality does not suit the needs of the test,
+// custom equality functions can override the equality operation.
+// For example, an equality function may report floats as equal so long as they
+// are within some tolerance of each other.
+//
+// • Types that have an Equal method may use that method to determine equality.
+// This allows package authors to determine the equality operation for the types
+// that they define.
+//
+// • If no custom equality functions are used and no Equal method is defined,
+// equality is determined by recursively comparing the primitive kinds on both
+// values, much like reflect.DeepEqual. Unlike reflect.DeepEqual, unexported
+// fields are not compared by default; they result in panics unless suppressed
+// by using an Ignore option (see cmpopts.IgnoreUnexported) or explicitly compared
+// using the AllowUnexported option.
+package cmp
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+
+	"github.com/google/go-cmp/cmp/internal/diff"
+	"github.com/google/go-cmp/cmp/internal/function"
+	"github.com/google/go-cmp/cmp/internal/value"
+)
+
+// Equal reports whether x and y are equal by recursively applying the
+// following rules in the given order to x and y and all of their sub-values:
+//
+// • Let S be the set of all Ignore, Transformer, and Comparer options that
+// remain after applying all path filters, value filters, and type filters.
+// If at least one Ignore exists in S, then the comparison is ignored.
+// If the number of Transformer and Comparer options in S is greater than one,
+// then Equal panics because it is ambiguous which option to use.
+// If S contains a single Transformer, then use that to transform the current
+// values and recursively call Equal on the output values.
+// If S contains a single Comparer, then use that to compare the current values.
+// Otherwise, evaluation proceeds to the next rule.
+//
+// • If the values have an Equal method of the form "(T) Equal(T) bool" or
+// "(T) Equal(I) bool" where T is assignable to I, then use the result of
+// x.Equal(y) even if x or y is nil. Otherwise, no such method exists and
+// evaluation proceeds to the next rule.
+//
+// • Lastly, try to compare x and y based on their basic kinds.
+// Simple kinds like booleans, integers, floats, complex numbers, strings, and
+// channels are compared using the equivalent of the == operator in Go.
+// Functions are only equal if they are both nil, otherwise they are unequal.
+//
+// Structs are equal if recursively calling Equal on all fields report equal.
+// If a struct contains unexported fields, Equal panics unless an Ignore option
+// (e.g., cmpopts.IgnoreUnexported) ignores that field or the AllowUnexported
+// option explicitly permits comparing the unexported field.
+//
+// Slices are equal if they are both nil or both non-nil, where recursively
+// calling Equal on all non-ignored slice or array elements report equal.
+// Empty non-nil slices and nil slices are not equal; to equate empty slices,
+// consider using cmpopts.EquateEmpty.
+//
+// Maps are equal if they are both nil or both non-nil, where recursively
+// calling Equal on all non-ignored map entries report equal.
+// Map keys are equal according to the == operator.
+// To use custom comparisons for map keys, consider using cmpopts.SortMaps.
+// Empty non-nil maps and nil maps are not equal; to equate empty maps,
+// consider using cmpopts.EquateEmpty.
+//
+// Pointers and interfaces are equal if they are both nil or both non-nil,
+// where they have the same underlying concrete type and recursively
+// calling Equal on the underlying values reports equal.
+func Equal(x, y interface{}, opts ...Option) bool {
+	vx := reflect.ValueOf(x)
+	vy := reflect.ValueOf(y)
+
+	// If the inputs are different types, auto-wrap them in an empty interface
+	// so that they have the same parent type.
+	var t reflect.Type
+	if !vx.IsValid() || !vy.IsValid() || vx.Type() != vy.Type() {
+		t = reflect.TypeOf((*interface{})(nil)).Elem()
+		if vx.IsValid() {
+			vvx := reflect.New(t).Elem()
+			vvx.Set(vx)
+			vx = vvx
+		}
+		if vy.IsValid() {
+			vvy := reflect.New(t).Elem()
+			vvy.Set(vy)
+			vy = vvy
+		}
+	} else {
+		t = vx.Type()
+	}
+
+	s := newState(opts)
+	s.compareAny(&pathStep{t, vx, vy})
+	return s.result.Equal()
+}
+
+// Diff returns a human-readable report of the differences between two values.
+// It returns an empty string if and only if Equal returns true for the same
+// input values and options. The output string will use the "-" symbol to
+// indicate elements removed from x, and the "+" symbol to indicate elements
+// added to y.
+//
+// Do not depend on this output being stable.
+func Diff(x, y interface{}, opts ...Option) string {
+	r := new(defaultReporter)
+	opts = Options{Options(opts), reporter(r)}
+	eq := Equal(x, y, opts...)
+	d := r.String()
+	if (d == "") != eq {
+		panic("inconsistent difference and equality results")
+	}
+	return d
+}
+
+type state struct {
+	// These fields represent the "comparison state".
+	// Calling statelessCompare must not result in observable changes to these.
+	result    diff.Result      // The current result of comparison
+	curPath   Path             // The current path in the value tree
+	reporters []reporterOption // Optional reporters
+
+	// recChecker checks for infinite cycles applying the same set of
+	// transformers upon the output of itself.
+	recChecker recChecker
+
+	// dynChecker triggers pseudo-random checks for option correctness.
+	// It is safe for statelessCompare to mutate this value.
+	dynChecker dynChecker
+
+	// These fields, once set by processOption, will not change.
+	exporters map[reflect.Type]bool // Set of structs with unexported field visibility
+	opts      Options               // List of all fundamental and filter options
+}
+
+func newState(opts []Option) *state {
+	// Always ensure a validator option exists to validate the inputs.
+	s := &state{opts: Options{validator{}}}
+	for _, opt := range opts {
+		s.processOption(opt)
+	}
+	return s
+}
+
+func (s *state) processOption(opt Option) {
+	switch opt := opt.(type) {
+	case nil:
+	case Options:
+		for _, o := range opt {
+			s.processOption(o)
+		}
+	case coreOption:
+		type filtered interface {
+			isFiltered() bool
+		}
+		if fopt, ok := opt.(filtered); ok && !fopt.isFiltered() {
+			panic(fmt.Sprintf("cannot use an unfiltered option: %v", opt))
+		}
+		s.opts = append(s.opts, opt)
+	case visibleStructs:
+		if s.exporters == nil {
+			s.exporters = make(map[reflect.Type]bool)
+		}
+		for t := range opt {
+			s.exporters[t] = true
+		}
+	case reporterOption:
+		s.reporters = append(s.reporters, opt)
+	default:
+		panic(fmt.Sprintf("unknown option %T", opt))
+	}
+}
+
+// statelessCompare compares two values and returns the result.
+// This function is stateless in that it does not alter the current result,
+// or output to any registered reporters.
+func (s *state) statelessCompare(step PathStep) diff.Result {
+	// We do not save and restore the curPath because all of the compareX
+	// methods should properly push and pop from the path.
+	// It is an implementation bug if the contents of curPath differs from
+	// when calling this function to when returning from it.
+
+	oldResult, oldReporters := s.result, s.reporters
+	s.result = diff.Result{} // Reset result
+	s.reporters = nil        // Remove reporters to avoid spurious printouts
+	s.compareAny(step)
+	res := s.result
+	s.result, s.reporters = oldResult, oldReporters
+	return res
+}
+
+func (s *state) compareAny(step PathStep) {
+	// TODO: Support cyclic data structures.
+
+	// Update the path stack.
+	s.curPath.push(step)
+	defer s.curPath.pop()
+	for _, r := range s.reporters {
+		r.PushStep(step)
+		defer r.PopStep()
+	}
+	s.recChecker.Check(s.curPath)
+
+	// Obtain the current type and values.
+	t := step.Type()
+	vx, vy := step.Values()
+
+	// Rule 1: Check whether an option applies on this node in the value tree.
+	if s.tryOptions(t, vx, vy) {
+		return
+	}
+
+	// Rule 2: Check whether the type has a valid Equal method.
+	if s.tryMethod(t, vx, vy) {
+		return
+	}
+
+	// Rule 3: Recursively descend into each value's underlying kind.
+	switch t.Kind() {
+	case reflect.Bool:
+		s.report(vx.Bool() == vy.Bool(), 0)
+		return
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		s.report(vx.Int() == vy.Int(), 0)
+		return
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		s.report(vx.Uint() == vy.Uint(), 0)
+		return
+	case reflect.Float32, reflect.Float64:
+		s.report(vx.Float() == vy.Float(), 0)
+		return
+	case reflect.Complex64, reflect.Complex128:
+		s.report(vx.Complex() == vy.Complex(), 0)
+		return
+	case reflect.String:
+		s.report(vx.String() == vy.String(), 0)
+		return
+	case reflect.Chan, reflect.UnsafePointer:
+		s.report(vx.Pointer() == vy.Pointer(), 0)
+		return
+	case reflect.Func:
+		s.report(vx.IsNil() && vy.IsNil(), 0)
+		return
+	case reflect.Struct:
+		s.compareStruct(t, vx, vy)
+		return
+	case reflect.Slice:
+		if vx.IsNil() || vy.IsNil() {
+			s.report(vx.IsNil() && vy.IsNil(), 0)
+			return
+		}
+		fallthrough
+	case reflect.Array:
+		s.compareSlice(t, vx, vy)
+		return
+	case reflect.Map:
+		s.compareMap(t, vx, vy)
+		return
+	case reflect.Ptr:
+		if vx.IsNil() || vy.IsNil() {
+			s.report(vx.IsNil() && vy.IsNil(), 0)
+			return
+		}
+		vx, vy = vx.Elem(), vy.Elem()
+		s.compareAny(&indirect{pathStep{t.Elem(), vx, vy}})
+		return
+	case reflect.Interface:
+		if vx.IsNil() || vy.IsNil() {
+			s.report(vx.IsNil() && vy.IsNil(), 0)
+			return
+		}
+		vx, vy = vx.Elem(), vy.Elem()
+		if vx.Type() != vy.Type() {
+			s.report(false, 0)
+			return
+		}
+		s.compareAny(&typeAssertion{pathStep{vx.Type(), vx, vy}})
+		return
+	default:
+		panic(fmt.Sprintf("%v kind not handled", t.Kind()))
+	}
+}
+
+func (s *state) tryOptions(t reflect.Type, vx, vy reflect.Value) bool {
+	// Evaluate all filters and apply the remaining options.
+	if opt := s.opts.filter(s, t, vx, vy); opt != nil {
+		opt.apply(s, vx, vy)
+		return true
+	}
+	return false
+}
+
+func (s *state) tryMethod(t reflect.Type, vx, vy reflect.Value) bool {
+	// Check if this type even has an Equal method.
+	m, ok := t.MethodByName("Equal")
+	if !ok || !function.IsType(m.Type, function.EqualAssignable) {
+		return false
+	}
+
+	eq := s.callTTBFunc(m.Func, vx, vy)
+	s.report(eq, reportByMethod)
+	return true
+}
+
+func (s *state) callTRFunc(f, v reflect.Value, step *transform) reflect.Value {
+	v = sanitizeValue(v, f.Type().In(0))
+	if !s.dynChecker.Next() {
+		return f.Call([]reflect.Value{v})[0]
+	}
+
+	// Run the function twice and ensure that we get the same results back.
+	// We run in goroutines so that the race detector (if enabled) can detect
+	// unsafe mutations to the input.
+	c := make(chan reflect.Value)
+	go detectRaces(c, f, v)
+	got := <-c
+	want := f.Call([]reflect.Value{v})[0]
+	if step.vx, step.vy = got, want; !s.statelessCompare(step).Equal() {
+		// To avoid false-positives with non-reflexive equality operations,
+		// we sanity check whether a value is equal to itself.
+		if step.vx, step.vy = want, want; !s.statelessCompare(step).Equal() {
+			return want
+		}
+		panic(fmt.Sprintf("non-deterministic function detected: %s", function.NameOf(f)))
+	}
+	return want
+}
+
+func (s *state) callTTBFunc(f, x, y reflect.Value) bool {
+	x = sanitizeValue(x, f.Type().In(0))
+	y = sanitizeValue(y, f.Type().In(1))
+	if !s.dynChecker.Next() {
+		return f.Call([]reflect.Value{x, y})[0].Bool()
+	}
+
+	// Swapping the input arguments is sufficient to check that
+	// f is symmetric and deterministic.
+	// We run in goroutines so that the race detector (if enabled) can detect
+	// unsafe mutations to the input.
+	c := make(chan reflect.Value)
+	go detectRaces(c, f, y, x)
+	got := <-c
+	want := f.Call([]reflect.Value{x, y})[0].Bool()
+	if !got.IsValid() || got.Bool() != want {
+		panic(fmt.Sprintf("non-deterministic or non-symmetric function detected: %s", function.NameOf(f)))
+	}
+	return want
+}
+
+func detectRaces(c chan<- reflect.Value, f reflect.Value, vs ...reflect.Value) {
+	var ret reflect.Value
+	defer func() {
+		recover() // Ignore panics, let the other call to f panic instead
+		c <- ret
+	}()
+	ret = f.Call(vs)[0]
+}
+
+// sanitizeValue converts nil interfaces of type T to those of type R,
+// assuming that T is assignable to R.
+// Otherwise, it returns the input value as is.
+func sanitizeValue(v reflect.Value, t reflect.Type) reflect.Value {
+	// TODO(dsnet): Workaround for reflect bug (https://golang.org/issue/22143).
+	// The upstream fix landed in Go1.10, so we can remove this when drop support
+	// for Go1.9 and below.
+	if v.Kind() == reflect.Interface && v.IsNil() && v.Type() != t {
+		return reflect.New(t).Elem()
+	}
+	return v
+}
+
+func (s *state) compareStruct(t reflect.Type, vx, vy reflect.Value) {
+	var vax, vay reflect.Value // Addressable versions of vx and vy
+
+	step := &structField{}
+	for i := 0; i < t.NumField(); i++ {
+		step.typ = t.Field(i).Type
+		step.vx = vx.Field(i)
+		step.vy = vy.Field(i)
+		step.name = t.Field(i).Name
+		step.idx = i
+		step.unexported = !isExported(step.name)
+		if step.unexported {
+			if step.name == "_" {
+				continue
+			}
+			// Defer checking of unexported fields until later to give an
+			// Ignore a chance to ignore the field.
+			if !vax.IsValid() || !vay.IsValid() {
+				// For retrieveUnexportedField to work, the parent struct must
+				// be addressable. Create a new copy of the values if
+				// necessary to make them addressable.
+				vax = makeAddressable(vx)
+				vay = makeAddressable(vy)
+			}
+			step.mayForce = s.exporters[t]
+			step.pvx = vax
+			step.pvy = vay
+			step.field = t.Field(i)
+		}
+		s.compareAny(step)
+	}
+}
+
+func (s *state) compareSlice(t reflect.Type, vx, vy reflect.Value) {
+	step := &sliceIndex{pathStep: pathStep{typ: t.Elem()}}
+	withIndexes := func(ix, iy int) *sliceIndex {
+		if ix >= 0 {
+			step.vx, step.xkey = vx.Index(ix), ix
+		} else {
+			step.vx, step.xkey = reflect.Value{}, -1
+		}
+		if iy >= 0 {
+			step.vy, step.ykey = vy.Index(iy), iy
+		} else {
+			step.vy, step.ykey = reflect.Value{}, -1
+		}
+		return step
+	}
+
+	// Ignore options are able to ignore missing elements in a slice.
+	// However, detecting these reliably requires an optimal differencing
+	// algorithm, for which diff.Difference is not.
+	//
+	// Instead, we first iterate through both slices to detect which elements
+	// would be ignored if standing alone. The index of non-discarded elements
+	// are stored in a separate slice, which diffing is then performed on.
+	var indexesX, indexesY []int
+	var ignoredX, ignoredY []bool
+	for ix := 0; ix < vx.Len(); ix++ {
+		ignored := s.statelessCompare(withIndexes(ix, -1)).NumDiff == 0
+		if !ignored {
+			indexesX = append(indexesX, ix)
+		}
+		ignoredX = append(ignoredX, ignored)
+	}
+	for iy := 0; iy < vy.Len(); iy++ {
+		ignored := s.statelessCompare(withIndexes(-1, iy)).NumDiff == 0
+		if !ignored {
+			indexesY = append(indexesY, iy)
+		}
+		ignoredY = append(ignoredY, ignored)
+	}
+
+	// Compute an edit-script for slices vx and vy (excluding ignored elements).
+	edits := diff.Difference(len(indexesX), len(indexesY), func(ix, iy int) diff.Result {
+		return s.statelessCompare(withIndexes(indexesX[ix], indexesY[iy]))
+	})
+
+	// Replay the ignore-scripts and the edit-script.
+	var ix, iy int
+	for ix < vx.Len() || iy < vy.Len() {
+		var e diff.EditType
+		switch {
+		case ix < len(ignoredX) && ignoredX[ix]:
+			e = diff.UniqueX
+		case iy < len(ignoredY) && ignoredY[iy]:
+			e = diff.UniqueY
+		default:
+			e, edits = edits[0], edits[1:]
+		}
+		switch e {
+		case diff.UniqueX:
+			s.compareAny(withIndexes(ix, -1))
+			ix++
+		case diff.UniqueY:
+			s.compareAny(withIndexes(-1, iy))
+			iy++
+		default:
+			s.compareAny(withIndexes(ix, iy))
+			ix++
+			iy++
+		}
+	}
+	return
+}
+
+func (s *state) compareMap(t reflect.Type, vx, vy reflect.Value) {
+	if vx.IsNil() || vy.IsNil() {
+		s.report(vx.IsNil() && vy.IsNil(), 0)
+		return
+	}
+
+	// We combine and sort the two map keys so that we can perform the
+	// comparisons in a deterministic order.
+	step := &mapIndex{pathStep: pathStep{typ: t.Elem()}}
+	for _, k := range value.SortKeys(append(vx.MapKeys(), vy.MapKeys()...)) {
+		step.vx = vx.MapIndex(k)
+		step.vy = vy.MapIndex(k)
+		step.key = k
+		if !step.vx.IsValid() && !step.vy.IsValid() {
+			// It is possible for both vx and vy to be invalid if the
+			// key contained a NaN value in it.
+			//
+			// Even with the ability to retrieve NaN keys in Go 1.12,
+			// there still isn't a sensible way to compare the values since
+			// a NaN key may map to multiple unordered values.
+			// The most reasonable way to compare NaNs would be to compare the
+			// set of values. However, this is impossible to do efficiently
+			// since set equality is provably an O(n^2) operation given only
+			// an Equal function. If we had a Less function or Hash function,
+			// this could be done in O(n*log(n)) or O(n), respectively.
+			//
+			// Rather than adding complex logic to deal with NaNs, make it
+			// the user's responsibility to compare such obscure maps.
+			const help = "consider providing a Comparer to compare the map"
+			panic(fmt.Sprintf("%#v has map key with NaNs\n%s", s.curPath, help))
+		}
+		s.compareAny(step)
+	}
+}
+
+func (s *state) report(eq bool, rf reportFlags) {
+	if rf&reportIgnored == 0 {
+		if eq {
+			s.result.NumSame++
+			rf |= reportEqual
+		} else {
+			s.result.NumDiff++
+			rf |= reportUnequal
+		}
+	}
+	for _, r := range s.reporters {
+		r.Report(rf)
+	}
+}
+
+// recChecker tracks the state needed to periodically perform checks that
+// user provided transformers are not stuck in an infinitely recursive cycle.
+type recChecker struct{ next int }
+
+// Check scans the Path for any recursive transformers and panics when any
+// recursive transformers are detected. Note that the presence of a
+// recursive Transformer does not necessarily imply an infinite cycle.
+// As such, this check only activates after some minimal number of path steps.
+func (rc *recChecker) Check(p Path) {
+	const minLen = 1 << 16
+	if rc.next == 0 {
+		rc.next = minLen
+	}
+	if len(p) < rc.next {
+		return
+	}
+	rc.next <<= 1
+
+	// Check whether the same transformer has appeared at least twice.
+	var ss []string
+	m := map[Option]int{}
+	for _, ps := range p {
+		if t, ok := ps.(Transform); ok {
+			t := t.Option()
+			if m[t] == 1 { // Transformer was used exactly once before
+				tf := t.(*transformer).fnc.Type()
+				ss = append(ss, fmt.Sprintf("%v: %v => %v", t, tf.In(0), tf.Out(0)))
+			}
+			m[t]++
+		}
+	}
+	if len(ss) > 0 {
+		const warning = "recursive set of Transformers detected"
+		const help = "consider using cmpopts.AcyclicTransformer"
+		set := strings.Join(ss, "\n\t")
+		panic(fmt.Sprintf("%s:\n\t%s\n%s", warning, set, help))
+	}
+}
+
+// dynChecker tracks the state needed to periodically perform checks that
+// user provided functions are symmetric and deterministic.
+// The zero value is safe for immediate use.
+type dynChecker struct{ curr, next int }
+
+// Next increments the state and reports whether a check should be performed.
+//
+// Checks occur every Nth function call, where N is a triangular number:
+//	0 1 3 6 10 15 21 28 36 45 55 66 78 91 105 120 136 153 171 190 ...
+// See https://en.wikipedia.org/wiki/Triangular_number
+//
+// This sequence ensures that the cost of checks drops significantly as
+// the number of functions calls grows larger.
+func (dc *dynChecker) Next() bool {
+	ok := dc.curr == dc.next
+	if ok {
+		dc.curr = 0
+		dc.next++
+	}
+	dc.curr++
+	return ok
+}
+
+// makeAddressable returns a value that is always addressable.
+// It returns the input verbatim if it is already addressable,
+// otherwise it creates a new value and returns an addressable copy.
+func makeAddressable(v reflect.Value) reflect.Value {
+	if v.CanAddr() {
+		return v
+	}
+	vc := reflect.New(v.Type()).Elem()
+	vc.Set(v)
+	return vc
+}

vendor/github.com/google/go-cmp/cmp/export_panic.go

@@ -0,0 +1,15 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+// +build purego
+
+package cmp
+
+import "reflect"
+
+const supportAllowUnexported = false
+
+func retrieveUnexportedField(reflect.Value, reflect.StructField) reflect.Value {
+	panic("retrieveUnexportedField is not implemented")
+}

vendor/github.com/google/go-cmp/cmp/export_unsafe.go

@@ -0,0 +1,23 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+// +build !purego
+
+package cmp
+
+import (
+	"reflect"
+	"unsafe"
+)
+
+const supportAllowUnexported = true
+
+// retrieveUnexportedField uses unsafe to forcibly retrieve any field from
+// a struct such that the value has read-write permissions.
+//
+// The parent struct, v, must be addressable, while f must be a StructField
+// describing the field to retrieve.
+func retrieveUnexportedField(v reflect.Value, f reflect.StructField) reflect.Value {
+	return reflect.NewAt(f.Type, unsafe.Pointer(v.UnsafeAddr()+f.Offset)).Elem()
+}

vendor/github.com/google/go-cmp/cmp/internal/diff/debug_disable.go

@@ -0,0 +1,17 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+// +build !cmp_debug
+
+package diff
+
+var debug debugger
+
+type debugger struct{}
+
+func (debugger) Begin(_, _ int, f EqualFunc, _, _ *EditScript) EqualFunc {
+	return f
+}
+func (debugger) Update() {}
+func (debugger) Finish() {}

vendor/github.com/google/go-cmp/cmp/internal/diff/debug_enable.go

@@ -0,0 +1,122 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+// +build cmp_debug
+
+package diff
+
+import (
+	"fmt"
+	"strings"
+	"sync"
+	"time"
+)
+
+// The algorithm can be seen running in real-time by enabling debugging:
+//	go test -tags=cmp_debug -v
+//
+// Example output:
+//	=== RUN   TestDifference/#34
+//	┌───────────────────────────────┐
+//	│ \ · · · · · · · · · · · · · · │
+//	│ · # · · · · · · · · · · · · · │
+//	│ · \ · · · · · · · · · · · · · │
+//	│ · · \ · · · · · · · · · · · · │
+//	│ · · · X # · · · · · · · · · · │
+//	│ · · · # \ · · · · · · · · · · │
+//	│ · · · · · # # · · · · · · · · │
+//	│ · · · · · # \ · · · · · · · · │
+//	│ · · · · · · · \ · · · · · · · │
+//	│ · · · · · · · · \ · · · · · · │
+//	│ · · · · · · · · · \ · · · · · │
+//	│ · · · · · · · · · · \ · · # · │
+//	│ · · · · · · · · · · · \ # # · │
+//	│ · · · · · · · · · · · # # # · │
+//	│ · · · · · · · · · · # # # # · │
+//	│ · · · · · · · · · # # # # # · │
+//	│ · · · · · · · · · · · · · · \ │
+//	└───────────────────────────────┘
+//	[.Y..M.XY......YXYXY.|]
+//
+// The grid represents the edit-graph where the horizontal axis represents
+// list X and the vertical axis represents list Y. The start of the two lists
+// is the top-left, while the ends are the bottom-right. The '·' represents
+// an unexplored node in the graph. The '\' indicates that the two symbols
+// from list X and Y are equal. The 'X' indicates that two symbols are similar
+// (but not exactly equal) to each other. The '#' indicates that the two symbols
+// are different (and not similar). The algorithm traverses this graph trying to
+// make the paths starting in the top-left and the bottom-right connect.
+//
+// The series of '.', 'X', 'Y', and 'M' characters at the bottom represents
+// the currently established path from the forward and reverse searches,
+// separated by a '|' character.
+
+const (
+	updateDelay  = 100 * time.Millisecond
+	finishDelay  = 500 * time.Millisecond
+	ansiTerminal = true // ANSI escape codes used to move terminal cursor
+)
+
+var debug debugger
+
+type debugger struct {
+	sync.Mutex
+	p1, p2           EditScript
+	fwdPath, revPath *EditScript
+	grid             []byte
+	lines            int
+}
+
+func (dbg *debugger) Begin(nx, ny int, f EqualFunc, p1, p2 *EditScript) EqualFunc {
+	dbg.Lock()
+	dbg.fwdPath, dbg.revPath = p1, p2
+	top := "┌─" + strings.Repeat("──", nx) + "┐\n"
+	row := "│ " + strings.Repeat("· ", nx) + "│\n"
+	btm := "└─" + strings.Repeat("──", nx) + "┘\n"
+	dbg.grid = []byte(top + strings.Repeat(row, ny) + btm)
+	dbg.lines = strings.Count(dbg.String(), "\n")
+	fmt.Print(dbg)
+
+	// Wrap the EqualFunc so that we can intercept each result.
+	return func(ix, iy int) (r Result) {
+		cell := dbg.grid[len(top)+iy*len(row):][len("│ ")+len("· ")*ix:][:len("·")]
+		for i := range cell {
+			cell[i] = 0 // Zero out the multiple bytes of UTF-8 middle-dot
+		}
+		switch r = f(ix, iy); {
+		case r.Equal():
+			cell[0] = '\\'
+		case r.Similar():
+			cell[0] = 'X'
+		default:
+			cell[0] = '#'
+		}
+		return
+	}
+}
+
+func (dbg *debugger) Update() {
+	dbg.print(updateDelay)
+}
+
+func (dbg *debugger) Finish() {
+	dbg.print(finishDelay)
+	dbg.Unlock()
+}
+
+func (dbg *debugger) String() string {
+	dbg.p1, dbg.p2 = *dbg.fwdPath, dbg.p2[:0]
+	for i := len(*dbg.revPath) - 1; i >= 0; i-- {
+		dbg.p2 = append(dbg.p2, (*dbg.revPath)[i])
+	}
+	return fmt.Sprintf("%s[%v|%v]\n\n", dbg.grid, dbg.p1, dbg.p2)
+}
+
+func (dbg *debugger) print(d time.Duration) {
+	if ansiTerminal {
+		fmt.Printf("\x1b[%dA", dbg.lines) // Reset terminal cursor
+	}
+	fmt.Print(dbg)
+	time.Sleep(d)
+}

vendor/github.com/google/go-cmp/cmp/internal/diff/diff.go

@@ -0,0 +1,363 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+// Package diff implements an algorithm for producing edit-scripts.
+// The edit-script is a sequence of operations needed to transform one list
+// of symbols into another (or vice-versa). The edits allowed are insertions,
+// deletions, and modifications. The summation of all edits is called the
+// Levenshtein distance as this problem is well-known in computer science.
+//
+// This package prioritizes performance over accuracy. That is, the run time
+// is more important than obtaining a minimal Levenshtein distance.
+package diff
+
+// EditType represents a single operation within an edit-script.
+type EditType uint8
+
+const (
+	// Identity indicates that a symbol pair is identical in both list X and Y.
+	Identity EditType = iota
+	// UniqueX indicates that a symbol only exists in X and not Y.
+	UniqueX
+	// UniqueY indicates that a symbol only exists in Y and not X.
+	UniqueY
+	// Modified indicates that a symbol pair is a modification of each other.
+	Modified
+)
+
+// EditScript represents the series of differences between two lists.
+type EditScript []EditType
+
+// String returns a human-readable string representing the edit-script where
+// Identity, UniqueX, UniqueY, and Modified are represented by the
+// '.', 'X', 'Y', and 'M' characters, respectively.
+func (es EditScript) String() string {
+	b := make([]byte, len(es))
+	for i, e := range es {
+		switch e {
+		case Identity:
+			b[i] = '.'
+		case UniqueX:
+			b[i] = 'X'
+		case UniqueY:
+			b[i] = 'Y'
+		case Modified:
+			b[i] = 'M'
+		default:
+			panic("invalid edit-type")
+		}
+	}
+	return string(b)
+}
+
+// stats returns a histogram of the number of each type of edit operation.
+func (es EditScript) stats() (s struct{ NI, NX, NY, NM int }) {
+	for _, e := range es {
+		switch e {
+		case Identity:
+			s.NI++
+		case UniqueX:
+			s.NX++
+		case UniqueY:
+			s.NY++
+		case Modified:
+			s.NM++
+		default:
+			panic("invalid edit-type")
+		}
+	}
+	return
+}
+
+// Dist is the Levenshtein distance and is guaranteed to be 0 if and only if
+// lists X and Y are equal.
+func (es EditScript) Dist() int { return len(es) - es.stats().NI }
+
+// LenX is the length of the X list.
+func (es EditScript) LenX() int { return len(es) - es.stats().NY }
+
+// LenY is the length of the Y list.
+func (es EditScript) LenY() int { return len(es) - es.stats().NX }
+
+// EqualFunc reports whether the symbols at indexes ix and iy are equal.
+// When called by Difference, the index is guaranteed to be within nx and ny.
+type EqualFunc func(ix int, iy int) Result
+
+// Result is the result of comparison.
+// NumSame is the number of sub-elements that are equal.
+// NumDiff is the number of sub-elements that are not equal.
+type Result struct{ NumSame, NumDiff int }
+
+// Equal indicates whether the symbols are equal. Two symbols are equal
+// if and only if NumDiff == 0. If Equal, then they are also Similar.
+func (r Result) Equal() bool { return r.NumDiff == 0 }
+
+// Similar indicates whether two symbols are similar and may be represented
+// by using the Modified type. As a special case, we consider binary comparisons
+// (i.e., those that return Result{1, 0} or Result{0, 1}) to be similar.
+//
+// The exact ratio of NumSame to NumDiff to determine similarity may change.
+func (r Result) Similar() bool {
+	// Use NumSame+1 to offset NumSame so that binary comparisons are similar.
+	return r.NumSame+1 >= r.NumDiff
+}
+
+// Difference reports whether two lists of lengths nx and ny are equal
+// given the definition of equality provided as f.
+//
+// This function returns an edit-script, which is a sequence of operations
+// needed to convert one list into the other. The following invariants for
+// the edit-script are maintained:
+//	• eq == (es.Dist()==0)
+//	• nx == es.LenX()
+//	• ny == es.LenY()
+//
+// This algorithm is not guaranteed to be an optimal solution (i.e., one that
+// produces an edit-script with a minimal Levenshtein distance). This algorithm
+// favors performance over optimality. The exact output is not guaranteed to
+// be stable and may change over time.
+func Difference(nx, ny int, f EqualFunc) (es EditScript) {
+	// This algorithm is based on traversing what is known as an "edit-graph".
+	// See Figure 1 from "An O(ND) Difference Algorithm and Its Variations"
+	// by Eugene W. Myers. Since D can be as large as N itself, this is
+	// effectively O(N^2). Unlike the algorithm from that paper, we are not
+	// interested in the optimal path, but at least some "decent" path.
+	//
+	// For example, let X and Y be lists of symbols:
+	//	X = [A B C A B B A]
+	//	Y = [C B A B A C]
+	//
+	// The edit-graph can be drawn as the following:
+	//	   A B C A B B A
+	//	  ┌─────────────┐
+	//	C │_|_|\|_|_|_|_│ 0
+	//	B │_|\|_|_|\|\|_│ 1
+	//	A │\|_|_|\|_|_|\│ 2
+	//	B │_|\|_|_|\|\|_│ 3
+	//	A │\|_|_|\|_|_|\│ 4
+	//	C │ | |\| | | | │ 5
+	//	  └─────────────┘ 6
+	//	   0 1 2 3 4 5 6 7
+	//
+	// List X is written along the horizontal axis, while list Y is written
+	// along the vertical axis. At any point on this grid, if the symbol in
+	// list X matches the corresponding symbol in list Y, then a '\' is drawn.
+	// The goal of any minimal edit-script algorithm is to find a path from the
+	// top-left corner to the bottom-right corner, while traveling through the
+	// fewest horizontal or vertical edges.
+	// A horizontal edge is equivalent to inserting a symbol from list X.
+	// A vertical edge is equivalent to inserting a symbol from list Y.
+	// A diagonal edge is equivalent to a matching symbol between both X and Y.
+
+	// Invariants:
+	//	• 0 ≤ fwdPath.X ≤ (fwdFrontier.X, revFrontier.X) ≤ revPath.X ≤ nx
+	//	• 0 ≤ fwdPath.Y ≤ (fwdFrontier.Y, revFrontier.Y) ≤ revPath.Y ≤ ny
+	//
+	// In general:
+	//	• fwdFrontier.X < revFrontier.X
+	//	• fwdFrontier.Y < revFrontier.Y
+	// Unless, it is time for the algorithm to terminate.
+	fwdPath := path{+1, point{0, 0}, make(EditScript, 0, (nx+ny)/2)}
+	revPath := path{-1, point{nx, ny}, make(EditScript, 0)}
+	fwdFrontier := fwdPath.point // Forward search frontier
+	revFrontier := revPath.point // Reverse search frontier
+
+	// Search budget bounds the cost of searching for better paths.
+	// The longest sequence of non-matching symbols that can be tolerated is
+	// approximately the square-root of the search budget.
+	searchBudget := 4 * (nx + ny) // O(n)
+
+	// The algorithm below is a greedy, meet-in-the-middle algorithm for
+	// computing sub-optimal edit-scripts between two lists.
+	//
+	// The algorithm is approximately as follows:
+	//	• Searching for differences switches back-and-forth between
+	//	a search that starts at the beginning (the top-left corner), and
+	//	a search that starts at the end (the bottom-right corner). The goal of
+	//	the search is connect with the search from the opposite corner.
+	//	• As we search, we build a path in a greedy manner, where the first
+	//	match seen is added to the path (this is sub-optimal, but provides a
+	//	decent result in practice). When matches are found, we try the next pair
+	//	of symbols in the lists and follow all matches as far as possible.
+	//	• When searching for matches, we search along a diagonal going through
+	//	through the "frontier" point. If no matches are found, we advance the
+	//	frontier towards the opposite corner.
+	//	• This algorithm terminates when either the X coordinates or the
+	//	Y coordinates of the forward and reverse frontier points ever intersect.
+	//
+	// This algorithm is correct even if searching only in the forward direction
+	// or in the reverse direction. We do both because it is commonly observed
+	// that two lists commonly differ because elements were added to the front
+	// or end of the other list.
+	//
+	// Running the tests with the "cmp_debug" build tag prints a visualization
+	// of the algorithm running in real-time. This is educational for
+	// understanding how the algorithm works. See debug_enable.go.
+	f = debug.Begin(nx, ny, f, &fwdPath.es, &revPath.es)
+	for {
+		// Forward search from the beginning.
+		if fwdFrontier.X >= revFrontier.X || fwdFrontier.Y >= revFrontier.Y || searchBudget == 0 {
+			break
+		}
+		for stop1, stop2, i := false, false, 0; !(stop1 && stop2) && searchBudget > 0; i++ {
+			// Search in a diagonal pattern for a match.
+			z := zigzag(i)
+			p := point{fwdFrontier.X + z, fwdFrontier.Y - z}
+			switch {
+			case p.X >= revPath.X || p.Y < fwdPath.Y:
+				stop1 = true // Hit top-right corner
+			case p.Y >= revPath.Y || p.X < fwdPath.X:
+				stop2 = true // Hit bottom-left corner
+			case f(p.X, p.Y).Equal():
+				// Match found, so connect the path to this point.
+				fwdPath.connect(p, f)
+				fwdPath.append(Identity)
+				// Follow sequence of matches as far as possible.
+				for fwdPath.X < revPath.X && fwdPath.Y < revPath.Y {
+					if !f(fwdPath.X, fwdPath.Y).Equal() {
+						break
+					}
+					fwdPath.append(Identity)
+				}
+				fwdFrontier = fwdPath.point
+				stop1, stop2 = true, true
+			default:
+				searchBudget-- // Match not found
+			}
+			debug.Update()
+		}
+		// Advance the frontier towards reverse point.
+		if revPath.X-fwdFrontier.X >= revPath.Y-fwdFrontier.Y {
+			fwdFrontier.X++
+		} else {
+			fwdFrontier.Y++
+		}
+
+		// Reverse search from the end.
+		if fwdFrontier.X >= revFrontier.X || fwdFrontier.Y >= revFrontier.Y || searchBudget == 0 {
+			break
+		}
+		for stop1, stop2, i := false, false, 0; !(stop1 && stop2) && searchBudget > 0; i++ {
+			// Search in a diagonal pattern for a match.
+			z := zigzag(i)
+			p := point{revFrontier.X - z, revFrontier.Y + z}
+			switch {
+			case fwdPath.X >= p.X || revPath.Y < p.Y:
+				stop1 = true // Hit bottom-left corner
+			case fwdPath.Y >= p.Y || revPath.X < p.X:
+				stop2 = true // Hit top-right corner
+			case f(p.X-1, p.Y-1).Equal():
+				// Match found, so connect the path to this point.
+				revPath.connect(p, f)
+				revPath.append(Identity)
+				// Follow sequence of matches as far as possible.
+				for fwdPath.X < revPath.X && fwdPath.Y < revPath.Y {
+					if !f(revPath.X-1, revPath.Y-1).Equal() {
+						break
+					}
+					revPath.append(Identity)
+				}
+				revFrontier = revPath.point
+				stop1, stop2 = true, true
+			default:
+				searchBudget-- // Match not found
+			}
+			debug.Update()
+		}
+		// Advance the frontier towards forward point.
+		if revFrontier.X-fwdPath.X >= revFrontier.Y-fwdPath.Y {
+			revFrontier.X--
+		} else {
+			revFrontier.Y--
+		}
+	}
+
+	// Join the forward and reverse paths and then append the reverse path.
+	fwdPath.connect(revPath.point, f)
+	for i := len(revPath.es) - 1; i >= 0; i-- {
+		t := revPath.es[i]
+		revPath.es = revPath.es[:i]
+		fwdPath.append(t)
+	}
+	debug.Finish()
+	return fwdPath.es
+}
+
+type path struct {
+	dir   int // +1 if forward, -1 if reverse
+	point     // Leading point of the EditScript path
+	es    EditScript
+}
+
+// connect appends any necessary Identity, Modified, UniqueX, or UniqueY types
+// to the edit-script to connect p.point to dst.
+func (p *path) connect(dst point, f EqualFunc) {
+	if p.dir > 0 {
+		// Connect in forward direction.
+		for dst.X > p.X && dst.Y > p.Y {
+			switch r := f(p.X, p.Y); {
+			case r.Equal():
+				p.append(Identity)
+			case r.Similar():
+				p.append(Modified)
+			case dst.X-p.X >= dst.Y-p.Y:
+				p.append(UniqueX)
+			default:
+				p.append(UniqueY)
+			}
+		}
+		for dst.X > p.X {
+			p.append(UniqueX)
+		}
+		for dst.Y > p.Y {
+			p.append(UniqueY)
+		}
+	} else {
+		// Connect in reverse direction.
+		for p.X > dst.X && p.Y > dst.Y {
+			switch r := f(p.X-1, p.Y-1); {
+			case r.Equal():
+				p.append(Identity)
+			case r.Similar():
+				p.append(Modified)
+			case p.Y-dst.Y >= p.X-dst.X:
+				p.append(UniqueY)
+			default:
+				p.append(UniqueX)
+			}
+		}
+		for p.X > dst.X {
+			p.append(UniqueX)
+		}
+		for p.Y > dst.Y {
+			p.append(UniqueY)
+		}
+	}
+}
+
+func (p *path) append(t EditType) {
+	p.es = append(p.es, t)
+	switch t {
+	case Identity, Modified:
+		p.add(p.dir, p.dir)
+	case UniqueX:
+		p.add(p.dir, 0)
+	case UniqueY:
+		p.add(0, p.dir)
+	}
+	debug.Update()
+}
+
+type point struct{ X, Y int }
+
+func (p *point) add(dx, dy int) { p.X += dx; p.Y += dy }
+
+// zigzag maps a consecutive sequence of integers to a zig-zag sequence.
+//	[0 1 2 3 4 5 ...] => [0 -1 +1 -2 +2 ...]
+func zigzag(x int) int {
+	if x&1 != 0 {
+		x = ^x
+	}
+	return x >> 1
+}

vendor/github.com/google/go-cmp/cmp/internal/function/func.go

@@ -0,0 +1,87 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+// Package function provides functionality for identifying function types.
+package function
+
+import (
+	"reflect"
+	"regexp"
+	"runtime"
+	"strings"
+)
+
+type funcType int
+
+const (
+	_ funcType = iota
+
+	ttbFunc // func(T, T) bool
+	tibFunc // func(T, I) bool
+	trFunc  // func(T) R
+
+	Equal           = ttbFunc // func(T, T) bool
+	EqualAssignable = tibFunc // func(T, I) bool; encapsulates func(T, T) bool
+	Transformer     = trFunc  // func(T) R
+	ValueFilter     = ttbFunc // func(T, T) bool
+	Less            = ttbFunc // func(T, T) bool
+)
+
+var boolType = reflect.TypeOf(true)
+
+// IsType reports whether the reflect.Type is of the specified function type.
+func IsType(t reflect.Type, ft funcType) bool {
+	if t == nil || t.Kind() != reflect.Func || t.IsVariadic() {
+		return false
+	}
+	ni, no := t.NumIn(), t.NumOut()
+	switch ft {
+	case ttbFunc: // func(T, T) bool
+		if ni == 2 && no == 1 && t.In(0) == t.In(1) && t.Out(0) == boolType {
+			return true
+		}
+	case tibFunc: // func(T, I) bool
+		if ni == 2 && no == 1 && t.In(0).AssignableTo(t.In(1)) && t.Out(0) == boolType {
+			return true
+		}
+	case trFunc: // func(T) R
+		if ni == 1 && no == 1 {
+			return true
+		}
+	}
+	return false
+}
+
+var lastIdentRx = regexp.MustCompile(`[_\p{L}][_\p{L}\p{N}]*$`)
+
+// NameOf returns the name of the function value.
+func NameOf(v reflect.Value) string {
+	fnc := runtime.FuncForPC(v.Pointer())
+	if fnc == nil {
+		return "<unknown>"
+	}
+	fullName := fnc.Name() // e.g., "long/path/name/mypkg.(*MyType).(long/path/name/mypkg.myMethod)-fm"
+
+	// Method closures have a "-fm" suffix.
+	fullName = strings.TrimSuffix(fullName, "-fm")
+
+	var name string
+	for len(fullName) > 0 {
+		inParen := strings.HasSuffix(fullName, ")")
+		fullName = strings.TrimSuffix(fullName, ")")
+
+		s := lastIdentRx.FindString(fullName)
+		if s == "" {
+			break
+		}
+		name = s + "." + name
+		fullName = strings.TrimSuffix(fullName, s)
+
+		if i := strings.LastIndexByte(fullName, '('); inParen && i >= 0 {
+			fullName = fullName[:i]
+		}
+		fullName = strings.TrimSuffix(fullName, ".")
+	}
+	return strings.TrimSuffix(name, ".")
+}

vendor/github.com/google/go-cmp/cmp/internal/value/format.go

@@ -0,0 +1,280 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+// Package value provides functionality for reflect.Value types.
+package value
+
+import (
+	"fmt"
+	"reflect"
+	"strconv"
+	"strings"
+	"unicode"
+)
+
+var stringerIface = reflect.TypeOf((*fmt.Stringer)(nil)).Elem()
+
+// Format formats the value v as a string.
+//
+// This is similar to fmt.Sprintf("%+v", v) except this:
+//	* Prints the type unless it can be elided
+//	* Avoids printing struct fields that are zero
+//	* Prints a nil-slice as being nil, not empty
+//	* Prints map entries in deterministic order
+func Format(v reflect.Value, conf FormatConfig) string {
+	conf.printType = true
+	conf.followPointers = true
+	conf.realPointers = true
+	return formatAny(v, conf, visited{})
+}
+
+type FormatConfig struct {
+	UseStringer        bool // Should the String method be used if available?
+	printType          bool // Should we print the type before the value?
+	PrintPrimitiveType bool // Should we print the type of primitives?
+	followPointers     bool // Should we recursively follow pointers?
+	realPointers       bool // Should we print the real address of pointers?
+}
+
+func formatAny(v reflect.Value, conf FormatConfig, m visited) string {
+	// TODO: Should this be a multi-line printout in certain situations?
+
+	if !v.IsValid() {
+		return "<non-existent>"
+	}
+	if conf.UseStringer && v.Type().Implements(stringerIface) && v.CanInterface() {
+		if (v.Kind() == reflect.Ptr || v.Kind() == reflect.Interface) && v.IsNil() {
+			return "<nil>"
+		}
+
+		const stringerPrefix = "s" // Indicates that the String method was used
+		s := v.Interface().(fmt.Stringer).String()
+		return stringerPrefix + formatString(s)
+	}
+
+	switch v.Kind() {
+	case reflect.Bool:
+		return formatPrimitive(v.Type(), v.Bool(), conf)
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return formatPrimitive(v.Type(), v.Int(), conf)
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		if v.Type().PkgPath() == "" || v.Kind() == reflect.Uintptr {
+			// Unnamed uints are usually bytes or words, so use hexadecimal.
+			return formatPrimitive(v.Type(), formatHex(v.Uint()), conf)
+		}
+		return formatPrimitive(v.Type(), v.Uint(), conf)
+	case reflect.Float32, reflect.Float64:
+		return formatPrimitive(v.Type(), v.Float(), conf)
+	case reflect.Complex64, reflect.Complex128:
+		return formatPrimitive(v.Type(), v.Complex(), conf)
+	case reflect.String:
+		return formatPrimitive(v.Type(), formatString(v.String()), conf)
+	case reflect.UnsafePointer, reflect.Chan, reflect.Func:
+		return formatPointer(v, conf)
+	case reflect.Ptr:
+		if v.IsNil() {
+			if conf.printType {
+				return fmt.Sprintf("(%v)(nil)", v.Type())
+			}
+			return "<nil>"
+		}
+		if m.Visit(v) || !conf.followPointers {
+			return formatPointer(v, conf)
+		}
+		return "&" + formatAny(v.Elem(), conf, m)
+	case reflect.Interface:
+		if v.IsNil() {
+			if conf.printType {
+				return fmt.Sprintf("%v(nil)", v.Type())
+			}
+			return "<nil>"
+		}
+		return formatAny(v.Elem(), conf, m)
+	case reflect.Slice:
+		if v.IsNil() {
+			if conf.printType {
+				return fmt.Sprintf("%v(nil)", v.Type())
+			}
+			return "<nil>"
+		}
+		fallthrough
+	case reflect.Array:
+		var ss []string
+		subConf := conf
+		subConf.printType = v.Type().Elem().Kind() == reflect.Interface
+		for i := 0; i < v.Len(); i++ {
+			vi := v.Index(i)
+			if vi.CanAddr() { // Check for recursive elements
+				p := vi.Addr()
+				if m.Visit(p) {
+					subConf := conf
+					subConf.printType = true
+					ss = append(ss, "*"+formatPointer(p, subConf))
+					continue
+				}
+			}
+			ss = append(ss, formatAny(vi, subConf, m))
+		}
+		s := fmt.Sprintf("{%s}", strings.Join(ss, ", "))
+		if conf.printType {
+			return v.Type().String() + s
+		}
+		return s
+	case reflect.Map:
+		if v.IsNil() {
+			if conf.printType {
+				return fmt.Sprintf("%v(nil)", v.Type())
+			}
+			return "<nil>"
+		}
+		if m.Visit(v) {
+			return formatPointer(v, conf)
+		}
+
+		var ss []string
+		keyConf, valConf := conf, conf
+		keyConf.printType = v.Type().Key().Kind() == reflect.Interface
+		keyConf.followPointers = false
+		valConf.printType = v.Type().Elem().Kind() == reflect.Interface
+		for _, k := range SortKeys(v.MapKeys()) {
+			sk := formatAny(k, keyConf, m)
+			sv := formatAny(v.MapIndex(k), valConf, m)
+			ss = append(ss, fmt.Sprintf("%s: %s", sk, sv))
+		}
+		s := fmt.Sprintf("{%s}", strings.Join(ss, ", "))
+		if conf.printType {
+			return v.Type().String() + s
+		}
+		return s
+	case reflect.Struct:
+		var ss []string
+		subConf := conf
+		subConf.printType = true
+		for i := 0; i < v.NumField(); i++ {
+			vv := v.Field(i)
+			if isZero(vv) {
+				continue // Elide zero value fields
+			}
+			name := v.Type().Field(i).Name
+			subConf.UseStringer = conf.UseStringer
+			s := formatAny(vv, subConf, m)
+			ss = append(ss, fmt.Sprintf("%s: %s", name, s))
+		}
+		s := fmt.Sprintf("{%s}", strings.Join(ss, ", "))
+		if conf.printType {
+			return v.Type().String() + s
+		}
+		return s
+	default:
+		panic(fmt.Sprintf("%v kind not handled", v.Kind()))
+	}
+}
+
+func formatString(s string) string {
+	// Use quoted string if it the same length as a raw string literal.
+	// Otherwise, attempt to use the raw string form.
+	qs := strconv.Quote(s)
+	if len(qs) == 1+len(s)+1 {
+		return qs
+	}
+
+	// Disallow newlines to ensure output is a single line.
+	// Only allow printable runes for readability purposes.
+	rawInvalid := func(r rune) bool {
+		return r == '`' || r == '\n' || !unicode.IsPrint(r)
+	}
+	if strings.IndexFunc(s, rawInvalid) < 0 {
+		return "`" + s + "`"
+	}
+	return qs
+}
+
+func formatPrimitive(t reflect.Type, v interface{}, conf FormatConfig) string {
+	if conf.printType && (conf.PrintPrimitiveType || t.PkgPath() != "") {
+		return fmt.Sprintf("%v(%v)", t, v)
+	}
+	return fmt.Sprintf("%v", v)
+}
+
+func formatPointer(v reflect.Value, conf FormatConfig) string {
+	p := v.Pointer()
+	if !conf.realPointers {
+		p = 0 // For deterministic printing purposes
+	}
+	s := formatHex(uint64(p))
+	if conf.printType {
+		return fmt.Sprintf("(%v)(%s)", v.Type(), s)
+	}
+	return s
+}
+
+func formatHex(u uint64) string {
+	var f string
+	switch {
+	case u <= 0xff:
+		f = "0x%02x"
+	case u <= 0xffff:
+		f = "0x%04x"
+	case u <= 0xffffff:
+		f = "0x%06x"
+	case u <= 0xffffffff:
+		f = "0x%08x"
+	case u <= 0xffffffffff:
+		f = "0x%010x"
+	case u <= 0xffffffffffff:
+		f = "0x%012x"
+	case u <= 0xffffffffffffff:
+		f = "0x%014x"
+	case u <= 0xffffffffffffffff:
+		f = "0x%016x"
+	}
+	return fmt.Sprintf(f, u)
+}
+
+// isZero reports whether v is the zero value.
+// This does not rely on Interface and so can be used on unexported fields.
+func isZero(v reflect.Value) bool {
+	switch v.Kind() {
+	case reflect.Bool:
+		return v.Bool() == false
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return v.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return v.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return v.Float() == 0
+	case reflect.Complex64, reflect.Complex128:
+		return v.Complex() == 0
+	case reflect.String:
+		return v.String() == ""
+	case reflect.UnsafePointer:
+		return v.Pointer() == 0
+	case reflect.Chan, reflect.Func, reflect.Interface, reflect.Ptr, reflect.Map, reflect.Slice:
+		return v.IsNil()
+	case reflect.Array:
+		for i := 0; i < v.Len(); i++ {
+			if !isZero(v.Index(i)) {
+				return false
+			}
+		}
+		return true
+	case reflect.Struct:
+		for i := 0; i < v.NumField(); i++ {
+			if !isZero(v.Field(i)) {
+				return false
+			}
+		}
+		return true
+	}
+	return false
+}
+
+type visited map[Pointer]bool
+
+func (m visited) Visit(v reflect.Value) bool {
+	p := PointerOf(v)
+	visited := m[p]
+	m[p] = true
+	return visited
+}

vendor/github.com/google/go-cmp/cmp/internal/value/pointer_purego.go

@@ -0,0 +1,23 @@
+// Copyright 2018, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+// +build purego
+
+package value
+
+import "reflect"
+
+// Pointer is an opaque typed pointer and is guaranteed to be comparable.
+type Pointer struct {
+	p uintptr
+	t reflect.Type
+}
+
+// PointerOf returns a Pointer from v, which must be a
+// reflect.Ptr, reflect.Slice, or reflect.Map.
+func PointerOf(v reflect.Value) Pointer {
+	// NOTE: Storing a pointer as an uintptr is technically incorrect as it
+	// assumes that the GC implementation does not use a moving collector.
+	return Pointer{v.Pointer(), v.Type()}
+}

vendor/github.com/google/go-cmp/cmp/internal/value/pointer_unsafe.go

@@ -0,0 +1,26 @@
+// Copyright 2018, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+// +build !purego
+
+package value
+
+import (
+	"reflect"
+	"unsafe"
+)
+
+// Pointer is an opaque typed pointer and is guaranteed to be comparable.
+type Pointer struct {
+	p unsafe.Pointer
+	t reflect.Type
+}
+
+// PointerOf returns a Pointer from v, which must be a
+// reflect.Ptr, reflect.Slice, or reflect.Map.
+func PointerOf(v reflect.Value) Pointer {
+	// The proper representation of a pointer is unsafe.Pointer,
+	// which is necessary if the GC ever uses a moving collector.
+	return Pointer{unsafe.Pointer(v.Pointer()), v.Type()}
+}

vendor/github.com/google/go-cmp/cmp/internal/value/sort.go

@@ -0,0 +1,104 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+package value
+
+import (
+	"fmt"
+	"math"
+	"reflect"
+	"sort"
+)
+
+// SortKeys sorts a list of map keys, deduplicating keys if necessary.
+// The type of each value must be comparable.
+func SortKeys(vs []reflect.Value) []reflect.Value {
+	if len(vs) == 0 {
+		return vs
+	}
+
+	// Sort the map keys.
+	sort.Slice(vs, func(i, j int) bool { return isLess(vs[i], vs[j]) })
+
+	// Deduplicate keys (fails for NaNs).
+	vs2 := vs[:1]
+	for _, v := range vs[1:] {
+		if isLess(vs2[len(vs2)-1], v) {
+			vs2 = append(vs2, v)
+		}
+	}
+	return vs2
+}
+
+// isLess is a generic function for sorting arbitrary map keys.
+// The inputs must be of the same type and must be comparable.
+func isLess(x, y reflect.Value) bool {
+	switch x.Type().Kind() {
+	case reflect.Bool:
+		return !x.Bool() && y.Bool()
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return x.Int() < y.Int()
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return x.Uint() < y.Uint()
+	case reflect.Float32, reflect.Float64:
+		fx, fy := x.Float(), y.Float()
+		return fx < fy || math.IsNaN(fx) && !math.IsNaN(fy)
+	case reflect.Complex64, reflect.Complex128:
+		cx, cy := x.Complex(), y.Complex()
+		rx, ix, ry, iy := real(cx), imag(cx), real(cy), imag(cy)
+		if rx == ry || (math.IsNaN(rx) && math.IsNaN(ry)) {
+			return ix < iy || math.IsNaN(ix) && !math.IsNaN(iy)
+		}
+		return rx < ry || math.IsNaN(rx) && !math.IsNaN(ry)
+	case reflect.Ptr, reflect.UnsafePointer, reflect.Chan:
+		return x.Pointer() < y.Pointer()
+	case reflect.String:
+		return x.String() < y.String()
+	case reflect.Array:
+		for i := 0; i < x.Len(); i++ {
+			if isLess(x.Index(i), y.Index(i)) {
+				return true
+			}
+			if isLess(y.Index(i), x.Index(i)) {
+				return false
+			}
+		}
+		return false
+	case reflect.Struct:
+		for i := 0; i < x.NumField(); i++ {
+			if isLess(x.Field(i), y.Field(i)) {
+				return true
+			}
+			if isLess(y.Field(i), x.Field(i)) {
+				return false
+			}
+		}
+		return false
+	case reflect.Interface:
+		vx, vy := x.Elem(), y.Elem()
+		if !vx.IsValid() || !vy.IsValid() {
+			return !vx.IsValid() && vy.IsValid()
+		}
+		tx, ty := vx.Type(), vy.Type()
+		if tx == ty {
+			return isLess(x.Elem(), y.Elem())
+		}
+		if tx.Kind() != ty.Kind() {
+			return vx.Kind() < vy.Kind()
+		}
+		if tx.String() != ty.String() {
+			return tx.String() < ty.String()
+		}
+		if tx.PkgPath() != ty.PkgPath() {
+			return tx.PkgPath() < ty.PkgPath()
+		}
+		// This can happen in rare situations, so we fallback to just comparing
+		// the unique pointer for a reflect.Type. This guarantees deterministic
+		// ordering within a program, but it is obviously not stable.
+		return reflect.ValueOf(vx.Type()).Pointer() < reflect.ValueOf(vy.Type()).Pointer()
+	default:
+		// Must be Func, Map, or Slice; which are not comparable.
+		panic(fmt.Sprintf("%T is not comparable", x.Type()))
+	}
+}

vendor/github.com/google/go-cmp/cmp/options.go

@@ -0,0 +1,505 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+package cmp
+
+import (
+	"fmt"
+	"reflect"
+	"regexp"
+	"strings"
+
+	"github.com/google/go-cmp/cmp/internal/function"
+)
+
+// Option configures for specific behavior of Equal and Diff. In particular,
+// the fundamental Option functions (Ignore, Transformer, and Comparer),
+// configure how equality is determined.
+//
+// The fundamental options may be composed with filters (FilterPath and
+// FilterValues) to control the scope over which they are applied.
+//
+// The cmp/cmpopts package provides helper functions for creating options that
+// may be used with Equal and Diff.
+type Option interface {
+	// filter applies all filters and returns the option that remains.
+	// Each option may only read s.curPath and call s.callTTBFunc.
+	//
+	// An Options is returned only if multiple comparers or transformers
+	// can apply simultaneously and will only contain values of those types
+	// or sub-Options containing values of those types.
+	filter(s *state, t reflect.Type, vx, vy reflect.Value) applicableOption
+}
+
+// applicableOption represents the following types:
+//	Fundamental: ignore | validator | *comparer | *transformer
+//	Grouping:    Options
+type applicableOption interface {
+	Option
+
+	// apply executes the option, which may mutate s or panic.
+	apply(s *state, vx, vy reflect.Value)
+}
+
+// coreOption represents the following types:
+//	Fundamental: ignore | validator | *comparer | *transformer
+//	Filters:     *pathFilter | *valuesFilter
+type coreOption interface {
+	Option
+	isCore()
+}
+
+type core struct{}
+
+func (core) isCore() {}
+
+// Options is a list of Option values that also satisfies the Option interface.
+// Helper comparison packages may return an Options value when packing multiple
+// Option values into a single Option. When this package processes an Options,
+// it will be implicitly expanded into a flat list.
+//
+// Applying a filter on an Options is equivalent to applying that same filter
+// on all individual options held within.
+type Options []Option
+
+func (opts Options) filter(s *state, t reflect.Type, vx, vy reflect.Value) (out applicableOption) {
+	for _, opt := range opts {
+		switch opt := opt.filter(s, t, vx, vy); opt.(type) {
+		case ignore:
+			return ignore{} // Only ignore can short-circuit evaluation
+		case validator:
+			out = validator{} // Takes precedence over comparer or transformer
+		case *comparer, *transformer, Options:
+			switch out.(type) {
+			case nil:
+				out = opt
+			case validator:
+				// Keep validator
+			case *comparer, *transformer, Options:
+				out = Options{out, opt} // Conflicting comparers or transformers
+			}
+		}
+	}
+	return out
+}
+
+func (opts Options) apply(s *state, _, _ reflect.Value) {
+	const warning = "ambiguous set of applicable options"
+	const help = "consider using filters to ensure at most one Comparer or Transformer may apply"
+	var ss []string
+	for _, opt := range flattenOptions(nil, opts) {
+		ss = append(ss, fmt.Sprint(opt))
+	}
+	set := strings.Join(ss, "\n\t")
+	panic(fmt.Sprintf("%s at %#v:\n\t%s\n%s", warning, s.curPath, set, help))
+}
+
+func (opts Options) String() string {
+	var ss []string
+	for _, opt := range opts {
+		ss = append(ss, fmt.Sprint(opt))
+	}
+	return fmt.Sprintf("Options{%s}", strings.Join(ss, ", "))
+}
+
+// FilterPath returns a new Option where opt is only evaluated if filter f
+// returns true for the current Path in the value tree.
+//
+// This filter is called even if a slice element or map entry is missing and
+// provides an opportunity to ignore such cases. The filter function must be
+// symmetric such that the filter result is identical regardless of whether the
+// missing value is from x or y.
+//
+// The option passed in may be an Ignore, Transformer, Comparer, Options, or
+// a previously filtered Option.
+func FilterPath(f func(Path) bool, opt Option) Option {
+	if f == nil {
+		panic("invalid path filter function")
+	}
+	if opt := normalizeOption(opt); opt != nil {
+		return &pathFilter{fnc: f, opt: opt}
+	}
+	return nil
+}
+
+type pathFilter struct {
+	core
+	fnc func(Path) bool
+	opt Option
+}
+
+func (f pathFilter) filter(s *state, t reflect.Type, vx, vy reflect.Value) applicableOption {
+	if f.fnc(s.curPath) {
+		return f.opt.filter(s, t, vx, vy)
+	}
+	return nil
+}
+
+func (f pathFilter) String() string {
+	return fmt.Sprintf("FilterPath(%s, %v)", function.NameOf(reflect.ValueOf(f.fnc)), f.opt)
+}
+
+// FilterValues returns a new Option where opt is only evaluated if filter f,
+// which is a function of the form "func(T, T) bool", returns true for the
+// current pair of values being compared. If either value is invalid or
+// the type of the values is not assignable to T, then this filter implicitly
+// returns false.
+//
+// The filter function must be
+// symmetric (i.e., agnostic to the order of the inputs) and
+// deterministic (i.e., produces the same result when given the same inputs).
+// If T is an interface, it is possible that f is called with two values with
+// different concrete types that both implement T.
+//
+// The option passed in may be an Ignore, Transformer, Comparer, Options, or
+// a previously filtered Option.
+func FilterValues(f interface{}, opt Option) Option {
+	v := reflect.ValueOf(f)
+	if !function.IsType(v.Type(), function.ValueFilter) || v.IsNil() {
+		panic(fmt.Sprintf("invalid values filter function: %T", f))
+	}
+	if opt := normalizeOption(opt); opt != nil {
+		vf := &valuesFilter{fnc: v, opt: opt}
+		if ti := v.Type().In(0); ti.Kind() != reflect.Interface || ti.NumMethod() > 0 {
+			vf.typ = ti
+		}
+		return vf
+	}
+	return nil
+}
+
+type valuesFilter struct {
+	core
+	typ reflect.Type  // T
+	fnc reflect.Value // func(T, T) bool
+	opt Option
+}
+
+func (f valuesFilter) filter(s *state, t reflect.Type, vx, vy reflect.Value) applicableOption {
+	if !vx.IsValid() || !vx.CanInterface() || !vy.IsValid() || !vy.CanInterface() {
+		return nil
+	}
+	if (f.typ == nil || t.AssignableTo(f.typ)) && s.callTTBFunc(f.fnc, vx, vy) {
+		return f.opt.filter(s, t, vx, vy)
+	}
+	return nil
+}
+
+func (f valuesFilter) String() string {
+	return fmt.Sprintf("FilterValues(%s, %v)", function.NameOf(f.fnc), f.opt)
+}
+
+// Ignore is an Option that causes all comparisons to be ignored.
+// This value is intended to be combined with FilterPath or FilterValues.
+// It is an error to pass an unfiltered Ignore option to Equal.
+func Ignore() Option { return ignore{} }
+
+type ignore struct{ core }
+
+func (ignore) isFiltered() bool                                                     { return false }
+func (ignore) filter(_ *state, _ reflect.Type, _, _ reflect.Value) applicableOption { return ignore{} }
+func (ignore) apply(s *state, _, _ reflect.Value)                                   { s.report(true, reportIgnored) }
+func (ignore) String() string                                                       { return "Ignore()" }
+
+// validator is a sentinel Option type to indicate that some options could not
+// be evaluated due to unexported fields, missing slice elements, or
+// missing map entries. Both values are validator only for unexported fields.
+type validator struct{ core }
+
+func (validator) filter(_ *state, _ reflect.Type, vx, vy reflect.Value) applicableOption {
+	if !vx.IsValid() || !vy.IsValid() {
+		return validator{}
+	}
+	if !vx.CanInterface() || !vy.CanInterface() {
+		return validator{}
+	}
+	return nil
+}
+func (validator) apply(s *state, vx, vy reflect.Value) {
+	// Implies missing slice element or map entry.
+	if !vx.IsValid() || !vy.IsValid() {
+		s.report(vx.IsValid() == vy.IsValid(), 0)
+		return
+	}
+
+	// Unable to Interface implies unexported field without visibility access.
+	if !vx.CanInterface() || !vy.CanInterface() {
+		const help = "consider using a custom Comparer; if you control the implementation of type, you can also consider AllowUnexported or cmpopts.IgnoreUnexported"
+		panic(fmt.Sprintf("cannot handle unexported field: %#v\n%s", s.curPath, help))
+	}
+
+	panic("not reachable")
+}
+
+// identRx represents a valid identifier according to the Go specification.
+const identRx = `[_\p{L}][_\p{L}\p{N}]*`
+
+var identsRx = regexp.MustCompile(`^` + identRx + `(\.` + identRx + `)*$`)
+
+// Transformer returns an Option that applies a transformation function that
+// converts values of a certain type into that of another.
+//
+// The transformer f must be a function "func(T) R" that converts values of
+// type T to those of type R and is implicitly filtered to input values
+// assignable to T. The transformer must not mutate T in any way.
+//
+// To help prevent some cases of infinite recursive cycles applying the
+// same transform to the output of itself (e.g., in the case where the
+// input and output types are the same), an implicit filter is added such that
+// a transformer is applicable only if that exact transformer is not already
+// in the tail of the Path since the last non-Transform step.
+// For situations where the implicit filter is still insufficient,
+// consider using cmpopts.AcyclicTransformer, which adds a filter
+// to prevent the transformer from being recursively applied upon itself.
+//
+// The name is a user provided label that is used as the Transform.Name in the
+// transformation PathStep (and eventually shown in the Diff output).
+// The name must be a valid identifier or qualified identifier in Go syntax.
+// If empty, an arbitrary name is used.
+func Transformer(name string, f interface{}) Option {
+	v := reflect.ValueOf(f)
+	if !function.IsType(v.Type(), function.Transformer) || v.IsNil() {
+		panic(fmt.Sprintf("invalid transformer function: %T", f))
+	}
+	if name == "" {
+		name = function.NameOf(v)
+		if !identsRx.MatchString(name) {
+			name = "λ" // Lambda-symbol as placeholder name
+		}
+	} else if !identsRx.MatchString(name) {
+		panic(fmt.Sprintf("invalid name: %q", name))
+	}
+	tr := &transformer{name: name, fnc: reflect.ValueOf(f)}
+	if ti := v.Type().In(0); ti.Kind() != reflect.Interface || ti.NumMethod() > 0 {
+		tr.typ = ti
+	}
+	return tr
+}
+
+type transformer struct {
+	core
+	name string
+	typ  reflect.Type  // T
+	fnc  reflect.Value // func(T) R
+}
+
+func (tr *transformer) isFiltered() bool { return tr.typ != nil }
+
+func (tr *transformer) filter(s *state, t reflect.Type, _, _ reflect.Value) applicableOption {
+	for i := len(s.curPath) - 1; i >= 0; i-- {
+		if t, ok := s.curPath[i].(*transform); !ok {
+			break // Hit most recent non-Transform step
+		} else if tr == t.trans {
+			return nil // Cannot directly use same Transform
+		}
+	}
+	if tr.typ == nil || t.AssignableTo(tr.typ) {
+		return tr
+	}
+	return nil
+}
+
+func (tr *transformer) apply(s *state, vx, vy reflect.Value) {
+	step := &transform{pathStep{typ: tr.fnc.Type().Out(0)}, tr}
+	vvx := s.callTRFunc(tr.fnc, vx, step)
+	vvy := s.callTRFunc(tr.fnc, vy, step)
+	step.vx, step.vy = vvx, vvy
+	s.compareAny(step)
+}
+
+func (tr transformer) String() string {
+	return fmt.Sprintf("Transformer(%s, %s)", tr.name, function.NameOf(tr.fnc))
+}
+
+// Comparer returns an Option that determines whether two values are equal
+// to each other.
+//
+// The comparer f must be a function "func(T, T) bool" and is implicitly
+// filtered to input values assignable to T. If T is an interface, it is
+// possible that f is called with two values of different concrete types that
+// both implement T.
+//
+// The equality function must be:
+//	• Symmetric: equal(x, y) == equal(y, x)
+//	• Deterministic: equal(x, y) == equal(x, y)
+//	• Pure: equal(x, y) does not modify x or y
+func Comparer(f interface{}) Option {
+	v := reflect.ValueOf(f)
+	if !function.IsType(v.Type(), function.Equal) || v.IsNil() {
+		panic(fmt.Sprintf("invalid comparer function: %T", f))
+	}
+	cm := &comparer{fnc: v}
+	if ti := v.Type().In(0); ti.Kind() != reflect.Interface || ti.NumMethod() > 0 {
+		cm.typ = ti
+	}
+	return cm
+}
+
+type comparer struct {
+	core
+	typ reflect.Type  // T
+	fnc reflect.Value // func(T, T) bool
+}
+
+func (cm *comparer) isFiltered() bool { return cm.typ != nil }
+
+func (cm *comparer) filter(_ *state, t reflect.Type, _, _ reflect.Value) applicableOption {
+	if cm.typ == nil || t.AssignableTo(cm.typ) {
+		return cm
+	}
+	return nil
+}
+
+func (cm *comparer) apply(s *state, vx, vy reflect.Value) {
+	eq := s.callTTBFunc(cm.fnc, vx, vy)
+	s.report(eq, reportByFunc)
+}
+
+func (cm comparer) String() string {
+	return fmt.Sprintf("Comparer(%s)", function.NameOf(cm.fnc))
+}
+
+// AllowUnexported returns an Option that forcibly allows operations on
+// unexported fields in certain structs, which are specified by passing in a
+// value of each struct type.
+//
+// Users of this option must understand that comparing on unexported fields
+// from external packages is not safe since changes in the internal
+// implementation of some external package may cause the result of Equal
+// to unexpectedly change. However, it may be valid to use this option on types
+// defined in an internal package where the semantic meaning of an unexported
+// field is in the control of the user.
+//
+// In many cases, a custom Comparer should be used instead that defines
+// equality as a function of the public API of a type rather than the underlying
+// unexported implementation.
+//
+// For example, the reflect.Type documentation defines equality to be determined
+// by the == operator on the interface (essentially performing a shallow pointer
+// comparison) and most attempts to compare *regexp.Regexp types are interested
+// in only checking that the regular expression strings are equal.
+// Both of these are accomplished using Comparers:
+//
+//	Comparer(func(x, y reflect.Type) bool { return x == y })
+//	Comparer(func(x, y *regexp.Regexp) bool { return x.String() == y.String() })
+//
+// In other cases, the cmpopts.IgnoreUnexported option can be used to ignore
+// all unexported fields on specified struct types.
+func AllowUnexported(types ...interface{}) Option {
+	if !supportAllowUnexported {
+		panic("AllowUnexported is not supported on purego builds, Google App Engine Standard, or GopherJS")
+	}
+	m := make(map[reflect.Type]bool)
+	for _, typ := range types {
+		t := reflect.TypeOf(typ)
+		if t.Kind() != reflect.Struct {
+			panic(fmt.Sprintf("invalid struct type: %T", typ))
+		}
+		m[t] = true
+	}
+	return visibleStructs(m)
+}
+
+type visibleStructs map[reflect.Type]bool
+
+func (visibleStructs) filter(_ *state, _ reflect.Type, _, _ reflect.Value) applicableOption {
+	panic("not implemented")
+}
+
+// reportFlags is a bit-set representing how a comparison was determined.
+type reportFlags uint
+
+const (
+	_ reportFlags = (1 << iota) / 2
+
+	// reportEqual reports whether the node is equal.
+	// This may be ORed with reportByMethod or reportByFunc.
+	reportEqual
+	// reportUnequal reports whether the node is not equal.
+	// This may be ORed with reportByMethod or reportByFunc.
+	reportUnequal
+	// reportIgnored reports whether the node was ignored.
+	reportIgnored
+
+	// reportByMethod reports whether equality was determined by calling the
+	// Equal method. This may be ORed with reportEqual or reportUnequal.
+	reportByMethod
+	// reportByFunc reports whether equality was determined by calling a custom
+	// Comparer function. This may be ORed with reportEqual or reportUnequal.
+	reportByFunc
+)
+
+// reporter is an Option that can be passed to Equal. When Equal traverses
+// the value trees, it calls PushStep as it descends into each node in the
+// tree and PopStep as it ascend out of the node. The leaves of the tree are
+// either compared (determined to be equal or not equal) or ignored and reported
+// as such by calling the Report method.
+func reporter(r interface {
+	// TODO: Export this option.
+
+	// PushStep is called when a tree-traversal operation is performed.
+	// The PathStep itself is only valid until the step is popped.
+	// The PathStep.Values are valid for the duration of the entire traversal.
+	//
+	// Equal always call PushStep at the start to provide an operation-less
+	// PathStep used to report the root values.
+	//
+	// The entries of a map are iterated through in an unspecified order.
+	PushStep(PathStep)
+
+	// Report is called at exactly once on leaf nodes to report whether the
+	// comparison identified the node as equal, unequal, or ignored.
+	// A leaf node is one that is immediately preceded by and followed by
+	// a pair of PushStep and PopStep calls.
+	Report(reportFlags)
+
+	// PopStep ascends back up the value tree.
+	// There is always a matching pop call for every push call.
+	PopStep()
+}) Option {
+	return reporterOption{r}
+}
+
+type reporterOption struct{ reporterIface }
+type reporterIface interface {
+	PushStep(PathStep)
+	Report(reportFlags)
+	PopStep()
+}
+
+func (reporterOption) filter(_ *state, _ reflect.Type, _, _ reflect.Value) applicableOption {
+	panic("not implemented")
+}
+
+// normalizeOption normalizes the input options such that all Options groups
+// are flattened and groups with a single element are reduced to that element.
+// Only coreOptions and Options containing coreOptions are allowed.
+func normalizeOption(src Option) Option {
+	switch opts := flattenOptions(nil, Options{src}); len(opts) {
+	case 0:
+		return nil
+	case 1:
+		return opts[0]
+	default:
+		return opts
+	}
+}
+
+// flattenOptions copies all options in src to dst as a flat list.
+// Only coreOptions and Options containing coreOptions are allowed.
+func flattenOptions(dst, src Options) Options {
+	for _, opt := range src {
+		switch opt := opt.(type) {
+		case nil:
+			continue
+		case Options:
+			dst = flattenOptions(dst, opt)
+		case coreOption:
+			dst = append(dst, opt)
+		default:
+			panic(fmt.Sprintf("invalid option type: %T", opt))
+		}
+	}
+	return dst
+}

vendor/github.com/google/go-cmp/cmp/path.go

@@ -0,0 +1,342 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+package cmp
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+)
+
+type (
+	// Path is a list of PathSteps describing the sequence of operations to get
+	// from some root type to the current position in the value tree.
+	// The first Path element is always an operation-less PathStep that exists
+	// simply to identify the initial type.
+	//
+	// When traversing structs with embedded structs, the embedded struct will
+	// always be accessed as a field before traversing the fields of the
+	// embedded struct themselves. That is, an exported field from the
+	// embedded struct will never be accessed directly from the parent struct.
+	Path []PathStep
+
+	// PathStep is a union-type for specific operations to traverse
+	// a value's tree structure. Users of this package never need to implement
+	// these types as values of this type will be returned by this package.
+	PathStep interface {
+		String() string
+
+		// Type is the resulting type after performing the path step.
+		Type() reflect.Type
+
+		// Values is the resulting values after performing the path step.
+		// The type of each valid value is guaranteed to be identical to Type.
+		//
+		// In some cases, one or both may be invalid or have restrictions:
+		//	• For StructField, both are not interface-able if the current field
+		//	is unexported and the struct type is not explicitly permitted by
+		//	AllowUnexported to traverse unexported fields.
+		//	• For SliceIndex, one may be invalid if an element is missing from
+		//	either the x or y slice.
+		//	• For MapIndex, one may be invalid if an entry is missing from
+		//	either the x or y map.
+		//
+		// The provided values must not be mutated.
+		Values() (vx, vy reflect.Value)
+	}
+
+	// StructField represents a struct field access on a field called Name.
+	StructField interface {
+		PathStep
+
+		// Name is the field name.
+		Name() string
+
+		// Index is the index of the field in the parent struct type.
+		// See reflect.Type.Field.
+		Index() int
+
+		isStructField()
+	}
+	// SliceIndex is an index operation on a slice or array at some index Key.
+	SliceIndex interface {
+		PathStep
+
+		// Key is the index key; it may return -1 if in a split state
+		Key() int
+
+		// SplitKeys are the indexes for indexing into slices in the
+		// x and y values, respectively. These indexes may differ due to the
+		// insertion or removal of an element in one of the slices, causing
+		// all of the indexes to be shifted. If an index is -1, then that
+		// indicates that the element does not exist in the associated slice.
+		//
+		// Key is guaranteed to return -1 if and only if the indexes returned
+		// by SplitKeys are not the same. SplitKeys will never return -1 for
+		// both indexes.
+		SplitKeys() (ix, iy int)
+
+		isSliceIndex()
+	}
+	// MapIndex is an index operation on a map at some index Key.
+	MapIndex interface {
+		PathStep
+
+		// Key is the value of the map key.
+		Key() reflect.Value
+
+		isMapIndex()
+	}
+	// Indirect represents pointer indirection on the parent type.
+	Indirect interface {
+		PathStep
+
+		isIndirect()
+	}
+	// TypeAssertion represents a type assertion on an interface.
+	TypeAssertion interface {
+		PathStep
+
+		isTypeAssertion()
+	}
+	// Transform is a transformation from the parent type to the current type.
+	Transform interface {
+		PathStep
+
+		// Name is the name of the Transformer.
+		Name() string
+
+		// Func is the function pointer to the transformer function.
+		Func() reflect.Value
+
+		// Option returns the originally constructed Transformer option.
+		// The == operator can be used to detect the exact option used.
+		Option() Option
+
+		isTransform()
+	}
+)
+
+func (pa *Path) push(s PathStep) {
+	*pa = append(*pa, s)
+}
+
+func (pa *Path) pop() {
+	*pa = (*pa)[:len(*pa)-1]
+}
+
+// Last returns the last PathStep in the Path.
+// If the path is empty, this returns a non-nil PathStep that reports a nil Type.
+func (pa Path) Last() PathStep {
+	return pa.Index(-1)
+}
+
+// Index returns the ith step in the Path and supports negative indexing.
+// A negative index starts counting from the tail of the Path such that -1
+// refers to the last step, -2 refers to the second-to-last step, and so on.
+// If index is invalid, this returns a non-nil PathStep that reports a nil Type.
+func (pa Path) Index(i int) PathStep {
+	if i < 0 {
+		i = len(pa) + i
+	}
+	if i < 0 || i >= len(pa) {
+		return pathStep{}
+	}
+	return pa[i]
+}
+
+// String returns the simplified path to a node.
+// The simplified path only contains struct field accesses.
+//
+// For example:
+//	MyMap.MySlices.MyField
+func (pa Path) String() string {
+	var ss []string
+	for _, s := range pa {
+		if _, ok := s.(*structField); ok {
+			ss = append(ss, s.String())
+		}
+	}
+	return strings.TrimPrefix(strings.Join(ss, ""), ".")
+}
+
+// GoString returns the path to a specific node using Go syntax.
+//
+// For example:
+//	(*root.MyMap["key"].(*mypkg.MyStruct).MySlices)[2][3].MyField
+func (pa Path) GoString() string {
+	var ssPre, ssPost []string
+	var numIndirect int
+	for i, s := range pa {
+		var nextStep PathStep
+		if i+1 < len(pa) {
+			nextStep = pa[i+1]
+		}
+		switch s := s.(type) {
+		case *indirect:
+			numIndirect++
+			pPre, pPost := "(", ")"
+			switch nextStep.(type) {
+			case *indirect:
+				continue // Next step is indirection, so let them batch up
+			case *structField:
+				numIndirect-- // Automatic indirection on struct fields
+			case nil:
+				pPre, pPost = "", "" // Last step; no need for parenthesis
+			}
+			if numIndirect > 0 {
+				ssPre = append(ssPre, pPre+strings.Repeat("*", numIndirect))
+				ssPost = append(ssPost, pPost)
+			}
+			numIndirect = 0
+			continue
+		case *transform:
+			ssPre = append(ssPre, s.trans.name+"(")
+			ssPost = append(ssPost, ")")
+			continue
+		case *typeAssertion:
+			// As a special-case, elide type assertions on anonymous types
+			// since they are typically generated dynamically and can be very
+			// verbose. For example, some transforms return interface{} because
+			// of Go's lack of generics, but typically take in and return the
+			// exact same concrete type.
+			if s.Type().PkgPath() == "" {
+				continue
+			}
+		}
+		ssPost = append(ssPost, s.String())
+	}
+	for i, j := 0, len(ssPre)-1; i < j; i, j = i+1, j-1 {
+		ssPre[i], ssPre[j] = ssPre[j], ssPre[i]
+	}
+	return strings.Join(ssPre, "") + strings.Join(ssPost, "")
+}
+
+type (
+	pathStep struct {
+		typ    reflect.Type
+		vx, vy reflect.Value
+	}
+
+	structField struct {
+		pathStep
+		name string
+		idx  int
+
+		// These fields are used for forcibly accessing an unexported field.
+		// pvx, pvy, and field are only valid if unexported is true.
+		unexported bool
+		mayForce   bool                // Forcibly allow visibility
+		pvx, pvy   reflect.Value       // Parent values
+		field      reflect.StructField // Field information
+	}
+	sliceIndex struct {
+		pathStep
+		xkey, ykey int
+	}
+	mapIndex struct {
+		pathStep
+		key reflect.Value
+	}
+	indirect struct {
+		pathStep
+	}
+	typeAssertion struct {
+		pathStep
+	}
+	transform struct {
+		pathStep
+		trans *transformer
+	}
+)
+
+func (ps pathStep) Type() reflect.Type             { return ps.typ }
+func (ps pathStep) Values() (vx, vy reflect.Value) { return ps.vx, ps.vy }
+func (ps pathStep) String() string {
+	if ps.typ == nil {
+		return "<nil>"
+	}
+	s := ps.typ.String()
+	if s == "" || strings.ContainsAny(s, "{}\n") {
+		return "root" // Type too simple or complex to print
+	}
+	return fmt.Sprintf("{%s}", s)
+}
+func (ps pathStep) isPathStep() {}
+
+func (sf structField) Values() (vx, vy reflect.Value) {
+	if !sf.unexported {
+		return sf.vx, sf.vy // CanInterface reports true
+	}
+
+	// Forcibly obtain read-write access to an unexported struct field.
+	if sf.mayForce {
+		vx = retrieveUnexportedField(sf.pvx, sf.field)
+		vy = retrieveUnexportedField(sf.pvy, sf.field)
+		return vx, vy // CanInterface reports true
+	}
+	return sf.vx, sf.vy // CanInterface reports false
+}
+func (sf structField) String() string { return fmt.Sprintf(".%s", sf.name) }
+func (sf structField) Name() string   { return sf.name }
+func (sf structField) Index() int     { return sf.idx }
+func (sf structField) isStructField() {}
+
+func (si sliceIndex) String() string {
+	switch {
+	case si.xkey == si.ykey:
+		return fmt.Sprintf("[%d]", si.xkey)
+	case si.ykey == -1:
+		// [5->?] means "I don't know where X[5] went"
+		return fmt.Sprintf("[%d->?]", si.xkey)
+	case si.xkey == -1:
+		// [?->3] means "I don't know where Y[3] came from"
+		return fmt.Sprintf("[?->%d]", si.ykey)
+	default:
+		// [5->3] means "X[5] moved to Y[3]"
+		return fmt.Sprintf("[%d->%d]", si.xkey, si.ykey)
+	}
+}
+func (si sliceIndex) Key() int {
+	if si.xkey != si.ykey {
+		return -1
+	}
+	return si.xkey
+}
+func (si sliceIndex) SplitKeys() (ix, iy int) { return si.xkey, si.ykey }
+func (si sliceIndex) isSliceIndex()           {}
+
+func (mi mapIndex) String() string     { return fmt.Sprintf("[%#v]", mi.key) }
+func (mi mapIndex) Key() reflect.Value { return mi.key }
+func (mi mapIndex) isMapIndex()        {}
+
+func (in indirect) String() string { return "*" }
+func (in indirect) isIndirect()    {}
+
+func (ta typeAssertion) String() string   { return fmt.Sprintf(".(%v)", ta.typ) }
+func (ta typeAssertion) isTypeAssertion() {}
+
+func (tf transform) String() string      { return fmt.Sprintf("%s()", tf.trans.name) }
+func (tf transform) Name() string        { return tf.trans.name }
+func (tf transform) Func() reflect.Value { return tf.trans.fnc }
+func (tf transform) Option() Option      { return tf.trans }
+func (tf transform) isTransform()        {}
+
+var (
+	_ PathStep = StructField(structField{})
+	_ PathStep = SliceIndex(sliceIndex{})
+	_ PathStep = MapIndex(mapIndex{})
+	_ PathStep = Indirect(indirect{})
+	_ PathStep = TypeAssertion(typeAssertion{})
+	_ PathStep = Transform(transform{})
+)
+
+// isExported reports whether the identifier is exported.
+func isExported(id string) bool {
+	r, _ := utf8.DecodeRuneInString(id)
+	return unicode.IsUpper(r)
+}

vendor/github.com/google/go-cmp/cmp/report.go

@@ -0,0 +1,62 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+package cmp
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+
+	"github.com/google/go-cmp/cmp/internal/value"
+)
+
+type defaultReporter struct {
+	curPath Path
+
+	diffs  []string // List of differences, possibly truncated
+	ndiffs int      // Total number of differences
+	nbytes int      // Number of bytes in diffs
+	nlines int      // Number of lines in diffs
+}
+
+func (r *defaultReporter) PushStep(ps PathStep) {
+	r.curPath.push(ps)
+}
+func (r *defaultReporter) Report(f reportFlags) {
+	if f&reportUnequal > 0 {
+		vx, vy := r.curPath.Last().Values()
+		r.report(vx, vy, r.curPath)
+	}
+}
+func (r *defaultReporter) PopStep() {
+	r.curPath.pop()
+}
+
+func (r *defaultReporter) report(x, y reflect.Value, p Path) {
+	const maxBytes = 4096
+	const maxLines = 256
+	r.ndiffs++
+	if r.nbytes < maxBytes && r.nlines < maxLines {
+		sx := value.Format(x, value.FormatConfig{UseStringer: true})
+		sy := value.Format(y, value.FormatConfig{UseStringer: true})
+		if sx == sy {
+			// Unhelpful output, so use more exact formatting.
+			sx = value.Format(x, value.FormatConfig{PrintPrimitiveType: true})
+			sy = value.Format(y, value.FormatConfig{PrintPrimitiveType: true})
+		}
+		s := fmt.Sprintf("%#v:\n\t-: %s\n\t+: %s\n", p, sx, sy)
+		r.diffs = append(r.diffs, s)
+		r.nbytes += len(s)
+		r.nlines += strings.Count(s, "\n")
+	}
+}
+
+func (r *defaultReporter) String() string {
+	s := strings.Join(r.diffs, "")
+	if r.ndiffs == len(r.diffs) {
+		return s
+	}
+	return fmt.Sprintf("%s... %d more differences ...", s, r.ndiffs-len(r.diffs))
+}

vendor/vendor.json

@@ -176,6 +176,36 @@
 			"revision": "553a641470496b2327abcac10b36396bd98e45c9",
 			"revisionTime": "2017-02-15T23:32:05Z"
 		},
+		{
+			"checksumSHA1": "hgZvwSpZoZ+nzOJxP/4ivVe6rCE=",
+			"path": "github.com/google/go-cmp/cmp",
+			"revision": "c81281657ad99ba22e14fda7c4dfaaf2974c454e",
+			"revisionTime": "2019-02-28T02:41:37Z"
+		},
+		{
+			"checksumSHA1": "2b4rwcqKeRFkd9iT7+vQgBNVFM8=",
+			"path": "github.com/google/go-cmp/cmp/cmpopts",
+			"revision": "c81281657ad99ba22e14fda7c4dfaaf2974c454e",
+			"revisionTime": "2019-02-28T02:41:37Z"
+		},
+		{
+			"checksumSHA1": "ElnaXKknoOmCtSOuZ7mY3piHlRI=",
+			"path": "github.com/google/go-cmp/cmp/internal/diff",
+			"revision": "c81281657ad99ba22e14fda7c4dfaaf2974c454e",
+			"revisionTime": "2019-02-28T02:41:37Z"
+		},
+		{
+			"checksumSHA1": "aWCtRt+7QihHSosvSFse9RsjAGY=",
+			"path": "github.com/google/go-cmp/cmp/internal/function",
+			"revision": "c81281657ad99ba22e14fda7c4dfaaf2974c454e",
+			"revisionTime": "2019-02-28T02:41:37Z"
+		},
+		{
+			"checksumSHA1": "FLgIRNmxNGpYuHemKzoSzaPrqiQ=",
+			"path": "github.com/google/go-cmp/cmp/internal/value",
+			"revision": "c81281657ad99ba22e14fda7c4dfaaf2974c454e",
+			"revisionTime": "2019-02-28T02:41:37Z"
+		},
 		{
 			"checksumSHA1": "d9PxF1XQGLMJZRct2R8qVM/eYlE=",
 			"path": "github.com/hashicorp/golang-lru",