mirror of
https://github.com/ethereum/go-ethereum.git
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1f8e723821
Reduced the overhead caused by all the diffirent implementations of the vm.Environment interface. Where previously the Environment was an interface it has now become an implementation it self using several new easy to implement interfaces such as the Backend that takes care of the state and CallContext which takes care of the EVM calling conventions. Most of these interfaces have been implemented in the core package with the exception of the test suit which uses a combination of the core package implementations and a mix of its own. This will reduce the amount of extra overhead when changing an interface, such as adding a new method or changing a method signature.
96 lines
3.3 KiB
Go
96 lines
3.3 KiB
Go
// Copyright 2014 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package core
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import (
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"math/big"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/core/state"
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"github.com/ethereum/go-ethereum/core/types"
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"github.com/ethereum/go-ethereum/core/vm"
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)
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// ToEVMContext creates a new context for use in the EVM.
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func ToEVMContext(config *ChainConfig, msg Message, header *types.Header) vm.Context {
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var from common.Address
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if config.IsHomestead(header.Number) {
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from, _ = msg.From()
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} else {
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from, _ = msg.FromFrontier()
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}
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return vm.Context{
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CallContext: EVMCallContext{CanTransfer, Transfer},
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Origin: from,
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Coinbase: header.Coinbase,
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BlockNumber: new(big.Int).Set(header.Number),
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Time: new(big.Int).Set(header.Time),
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Difficulty: new(big.Int).Set(header.Difficulty),
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GasLimit: new(big.Int).Set(header.GasLimit),
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GasPrice: new(big.Int).Set(msg.GasPrice()),
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}
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}
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// GetHashFn returns a function for which the VM env can query block hashes through
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// up to the limit defined by the Yellow Paper and uses the given block chain
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// to query for information.
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func GetHashFn(ref common.Hash, chain *BlockChain) func(n uint64) common.Hash {
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return func(n uint64) common.Hash {
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for block := chain.GetBlockByHash(ref); block != nil; block = chain.GetBlock(block.ParentHash(), block.NumberU64()-1) {
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if block.NumberU64() == n {
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return block.Hash()
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}
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}
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return common.Hash{}
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}
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}
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// CanTransfer checks wether there are enough funds in the address' account to make a transfer.
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func CanTransfer(db vm.Database, addr common.Address, amount *big.Int) bool {
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return db.GetBalance(addr).Cmp(amount) >= 0
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}
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// Transfer subtracts amount from sender and adds amount to recipient using the given Db
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func Transfer(db vm.Database, sender, recipient common.Address, amount *big.Int) {
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db.SubBalance(sender, amount)
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db.AddBalance(recipient, amount)
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}
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// EVMBackend implements vm.Backend and provides an interface to keep track of the current
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// state.
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type EVMBackend struct {
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GetHashFn func(uint64) common.Hash // getHashFn callback is used to retrieve block hashes
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State *state.StateDB
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}
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// MakeSnapshot returns a copy of the state.
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func (b *EVMBackend) SnapshotDatabase() int {
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return b.State.Snapshot()
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}
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// Get returns the state
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func (b *EVMBackend) Get() vm.Database { return b.State }
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// Set sets the current state
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func (b *EVMBackend) RevertToSnapshot(revision int) { b.State.RevertToSnapshot(revision) }
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// GetHash returns the canonical hash referenced by the depth
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func (b *EVMBackend) GetHash(n uint64) common.Hash {
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return b.GetHashFn(n)
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}
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