consensus/clique, internal/web3ext: support hash based API queries

consensus/clique/api.go

@@ -31,7 +31,7 @@ type API struct {
 }
 
 // GetSnapshot retrieves the state snapshot at a given block.
-func (api *API) GetSnapshot(number *rpc.BlockNumber) (interface{}, error) {
+func (api *API) GetSnapshot(number *rpc.BlockNumber) (*snapshot, error) {
 	// Retrieve the requested block number (or current if none requested)
 	var header *types.Header
 	if number == nil || *number == rpc.LatestBlockNumber {
@@ -46,6 +46,15 @@ func (api *API) GetSnapshot(number *rpc.BlockNumber) (interface{}, error) {
 	return api.clique.snapshot(api.chain, header.Number.Uint64(), header.Hash(), nil)
 }
 
+// GetSnapshotAtHash retrieves the state snapshot at a given block.
+func (api *API) GetSnapshotAtHash(hash common.Hash) (*snapshot, error) {
+	header := api.chain.GetHeaderByHash(hash)
+	if header == nil {
+		return nil, errUnknownBlock
+	}
+	return api.clique.snapshot(api.chain, header.Number.Uint64(), header.Hash(), nil)
+}
+
 // GetSigners retrieves the list of authorized signers at the specified block.
 func (api *API) GetSigners(number *rpc.BlockNumber) ([]common.Address, error) {
 	// Retrieve the requested block number (or current if none requested)
@@ -66,6 +75,19 @@ func (api *API) GetSigners(number *rpc.BlockNumber) ([]common.Address, error) {
 	return snap.signers(), nil
 }
 
+// GetSignersAtHash retrieves the state snapshot at a given block.
+func (api *API) GetSignersAtHash(hash common.Hash) ([]common.Address, error) {
+	header := api.chain.GetHeaderByHash(hash)
+	if header == nil {
+		return nil, errUnknownBlock
+	}
+	snap, err := api.clique.snapshot(api.chain, header.Number.Uint64(), header.Hash(), nil)
+	if err != nil {
+		return nil, err
+	}
+	return snap.signers(), nil
+}
+
 // Proposals returns the current proposals the node tries to uphold and vote on.
 func (api *API) Proposals() map[common.Address]bool {
 	api.clique.lock.RLock()

consensus/clique/snapshot_test.go

@@ -78,6 +78,7 @@ func (r *testerChainReader) Config() *params.ChainConfig                 { panic
 func (r *testerChainReader) CurrentHeader() *types.Header                { panic("not supported") }
 func (r *testerChainReader) GetHeader(common.Hash, uint64) *types.Header { panic("not supported") }
 func (r *testerChainReader) GetBlock(common.Hash, uint64) *types.Block   { panic("not supported") }
+func (r *testerChainReader) GetHeaderByHash(common.Hash) *types.Header   { panic("not supported") }
 func (r *testerChainReader) GetHeaderByNumber(number uint64) *types.Header {
 	if number == 0 {
 		return core.GetHeader(r.db, core.GetCanonicalHash(r.db, 0), 0)

consensus/consensus.go

@@ -40,6 +40,9 @@ type ChainReader interface {
 	// GetHeaderByNumber retrieves a block header from the database by number.
 	GetHeaderByNumber(number uint64) *types.Header
 
+	// GetHeaderByHash retrieves a block header from the database by its hash.
+	GetHeaderByHash(hash common.Hash) *types.Header
+
 	// GetBlock retrieves a block from the database by hash and number.
 	GetBlock(hash common.Hash, number uint64) *types.Block
 }

internal/web3ext/web3ext.go

@@ -30,10 +30,8 @@ var Modules = map[string]string{
 	"shh":        Shh_JS,
 	"swarmfs":    SWARMFS_JS,
 	"txpool":     TxPool_JS,
-
 }
 
-
 const Chequebook_JS = `
 web3._extend({
   property: 'chequebook',
@@ -77,11 +75,21 @@ web3._extend({
 			params: 1,
       inputFormatter: [null]
 		}),
+		new web3._extend.Method({
+			name: 'getSnapshotAtHash',
+			call: 'clique_getSnapshotAtHash',
+			params: 1
+		}),
     new web3._extend.Method({
       name: 'getSigners',
       call: 'clique_getSigners',
       params: 1,
       inputFormatter: [null]
+    }),
+		new web3._extend.Method({
+			name: 'getSignersAtHash',
+			call: 'clique_getSignersAtHash',
+			params: 1
 		}),
 		new web3._extend.Method({
 			name: 'propose',