...

1 files changed, 523 insertions, 0 deletions

diff --git a/accounts/abi/bind/backends/simulated.go b/accounts/abi/bind/backends/simulated.go
new file mode 100644
index 0000000..88610a4
--- /dev/null
+++ b/accounts/abi/bind/backends/simulated.go
@@ -0,0 +1,523 @@
+// Copyright 2015 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 backends
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"math/big"
+	"sync"
+	"time"
+
+	"github.com/ava-labs/coreth/accounts/abi/bind"
+	"github.com/ava-labs/coreth/consensus/ethash"
+	"github.com/ava-labs/coreth/core"
+	"github.com/ava-labs/coreth/core/bloombits"
+	"github.com/ava-labs/coreth/core/rawdb"
+	"github.com/ava-labs/coreth/core/state"
+	"github.com/ava-labs/coreth/core/types"
+	"github.com/ava-labs/coreth/core/vm"
+	"github.com/ava-labs/coreth/params"
+	"github.com/ava-labs/coreth/rpc"
+	"github.com/ava-labs/go-ethereum"
+	"github.com/ava-labs/go-ethereum/common"
+	"github.com/ava-labs/go-ethereum/common/math"
+	"github.com/ava-labs/go-ethereum/eth/filters"
+	"github.com/ava-labs/go-ethereum/ethdb"
+	"github.com/ava-labs/go-ethereum/event"
+)
+
+// This nil assignment ensures compile time that SimulatedBackend implements bind.ContractBackend.
+var _ bind.ContractBackend = (*SimulatedBackend)(nil)
+
+var (
+	errBlockNumberUnsupported = errors.New("simulatedBackend cannot access blocks other than the latest block")
+	errGasEstimationFailed    = errors.New("gas required exceeds allowance or always failing transaction")
+)
+
+// SimulatedBackend implements bind.ContractBackend, simulating a blockchain in
+// the background. Its main purpose is to allow easily testing contract bindings.
+type SimulatedBackend struct {
+	database   ethdb.Database   // In memory database to store our testing data
+	blockchain *core.BlockChain // Ethereum blockchain to handle the consensus
+
+	mu           sync.Mutex
+	pendingBlock *types.Block   // Currently pending block that will be imported on request
+	pendingState *state.StateDB // Currently pending state that will be the active on on request
+
+	events *filters.EventSystem // Event system for filtering log events live
+
+	config *params.ChainConfig
+}
+
+// NewSimulatedBackendWithDatabase creates a new binding backend based on the given database
+// and uses a simulated blockchain for testing purposes.
+func NewSimulatedBackendWithDatabase(database ethdb.Database, alloc core.GenesisAlloc, gasLimit uint64) *SimulatedBackend {
+	genesis := core.Genesis{Config: params.AllEthashProtocolChanges, GasLimit: gasLimit, Alloc: alloc}
+	genesis.MustCommit(database)
+	blockchain, _ := core.NewBlockChain(database, nil, genesis.Config, ethash.NewFaker(), vm.Config{}, nil)
+
+	backend := &SimulatedBackend{
+		database:   database,
+		blockchain: blockchain,
+		config:     genesis.Config,
+		events:     filters.NewEventSystem(new(event.TypeMux), &filterBackend{database, blockchain}, false),
+	}
+	backend.rollback()
+	return backend
+}
+
+// NewSimulatedBackend creates a new binding backend using a simulated blockchain
+// for testing purposes.
+func NewSimulatedBackend(alloc core.GenesisAlloc, gasLimit uint64) *SimulatedBackend {
+	return NewSimulatedBackendWithDatabase(rawdb.NewMemoryDatabase(), alloc, gasLimit)
+}
+
+// Close terminates the underlying blockchain's update loop.
+func (b *SimulatedBackend) Close() error {
+	b.blockchain.Stop()
+	return nil
+}
+
+// Commit imports all the pending transactions as a single block and starts a
+// fresh new state.
+func (b *SimulatedBackend) Commit() {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	if _, err := b.blockchain.InsertChain([]*types.Block{b.pendingBlock}); err != nil {
+		panic(err) // This cannot happen unless the simulator is wrong, fail in that case
+	}
+	b.rollback()
+}
+
+// Rollback aborts all pending transactions, reverting to the last committed state.
+func (b *SimulatedBackend) Rollback() {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	b.rollback()
+}
+
+func (b *SimulatedBackend) rollback() {
+	blocks, _ := core.GenerateChain(b.config, b.blockchain.CurrentBlock(), ethash.NewFaker(), b.database, 1, func(int, *core.BlockGen) {})
+	statedb, _ := b.blockchain.State()
+
+	b.pendingBlock = blocks[0]
+	b.pendingState, _ = state.New(b.pendingBlock.Root(), statedb.Database())
+}
+
+// CodeAt returns the code associated with a certain account in the blockchain.
+func (b *SimulatedBackend) CodeAt(ctx context.Context, contract common.Address, blockNumber *big.Int) ([]byte, error) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	if blockNumber != nil && blockNumber.Cmp(b.blockchain.CurrentBlock().Number()) != 0 {
+		return nil, errBlockNumberUnsupported
+	}
+	statedb, _ := b.blockchain.State()
+	return statedb.GetCode(contract), nil
+}
+
+// BalanceAt returns the wei balance of a certain account in the blockchain.
+func (b *SimulatedBackend) BalanceAt(ctx context.Context, contract common.Address, blockNumber *big.Int) (*big.Int, error) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	if blockNumber != nil && blockNumber.Cmp(b.blockchain.CurrentBlock().Number()) != 0 {
+		return nil, errBlockNumberUnsupported
+	}
+	statedb, _ := b.blockchain.State()
+	return statedb.GetBalance(contract), nil
+}
+
+// NonceAt returns the nonce of a certain account in the blockchain.
+func (b *SimulatedBackend) NonceAt(ctx context.Context, contract common.Address, blockNumber *big.Int) (uint64, error) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	if blockNumber != nil && blockNumber.Cmp(b.blockchain.CurrentBlock().Number()) != 0 {
+		return 0, errBlockNumberUnsupported
+	}
+	statedb, _ := b.blockchain.State()
+	return statedb.GetNonce(contract), nil
+}
+
+// StorageAt returns the value of key in the storage of an account in the blockchain.
+func (b *SimulatedBackend) StorageAt(ctx context.Context, contract common.Address, key common.Hash, blockNumber *big.Int) ([]byte, error) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	if blockNumber != nil && blockNumber.Cmp(b.blockchain.CurrentBlock().Number()) != 0 {
+		return nil, errBlockNumberUnsupported
+	}
+	statedb, _ := b.blockchain.State()
+	val := statedb.GetState(contract, key)
+	return val[:], nil
+}
+
+// TransactionReceipt returns the receipt of a transaction.
+func (b *SimulatedBackend) TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error) {
+	receipt, _, _, _ := rawdb.ReadReceipt(b.database, txHash, b.config)
+	return receipt, nil
+}
+
+// TransactionByHash checks the pool of pending transactions in addition to the
+// blockchain. The isPending return value indicates whether the transaction has been
+// mined yet. Note that the transaction may not be part of the canonical chain even if
+// it's not pending.
+func (b *SimulatedBackend) TransactionByHash(ctx context.Context, txHash common.Hash) (*types.Transaction, bool, error) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	tx := b.pendingBlock.Transaction(txHash)
+	if tx != nil {
+		return tx, true, nil
+	}
+	tx, _, _, _ = rawdb.ReadTransaction(b.database, txHash)
+	if tx != nil {
+		return tx, false, nil
+	}
+	return nil, false, ethereum.NotFound
+}
+
+// PendingCodeAt returns the code associated with an account in the pending state.
+func (b *SimulatedBackend) PendingCodeAt(ctx context.Context, contract common.Address) ([]byte, error) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	return b.pendingState.GetCode(contract), nil
+}
+
+// CallContract executes a contract call.
+func (b *SimulatedBackend) CallContract(ctx context.Context, call ethereum.CallMsg, blockNumber *big.Int) ([]byte, error) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	if blockNumber != nil && blockNumber.Cmp(b.blockchain.CurrentBlock().Number()) != 0 {
+		return nil, errBlockNumberUnsupported
+	}
+	state, err := b.blockchain.State()
+	if err != nil {
+		return nil, err
+	}
+	rval, _, _, err := b.callContract(ctx, call, b.blockchain.CurrentBlock(), state)
+	return rval, err
+}
+
+// PendingCallContract executes a contract call on the pending state.
+func (b *SimulatedBackend) PendingCallContract(ctx context.Context, call ethereum.CallMsg) ([]byte, error) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	defer b.pendingState.RevertToSnapshot(b.pendingState.Snapshot())
+
+	rval, _, _, err := b.callContract(ctx, call, b.pendingBlock, b.pendingState)
+	return rval, err
+}
+
+// PendingNonceAt implements PendingStateReader.PendingNonceAt, retrieving
+// the nonce currently pending for the account.
+func (b *SimulatedBackend) PendingNonceAt(ctx context.Context, account common.Address) (uint64, error) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	return b.pendingState.GetOrNewStateObject(account).Nonce(), nil
+}
+
+// SuggestGasPrice implements ContractTransactor.SuggestGasPrice. Since the simulated
+// chain doesn't have miners, we just return a gas price of 1 for any call.
+func (b *SimulatedBackend) SuggestGasPrice(ctx context.Context) (*big.Int, error) {
+	return big.NewInt(1), nil
+}
+
+// EstimateGas executes the requested code against the currently pending block/state and
+// returns the used amount of gas.
+func (b *SimulatedBackend) EstimateGas(ctx context.Context, call ethereum.CallMsg) (uint64, error) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	// Determine the lowest and highest possible gas limits to binary search in between
+	var (
+		lo  uint64 = params.TxGas - 1
+		hi  uint64
+		cap uint64
+	)
+	if call.Gas >= params.TxGas {
+		hi = call.Gas
+	} else {
+		hi = b.pendingBlock.GasLimit()
+	}
+	cap = hi
+
+	// Create a helper to check if a gas allowance results in an executable transaction
+	executable := func(gas uint64) bool {
+		call.Gas = gas
+
+		snapshot := b.pendingState.Snapshot()
+		_, _, failed, err := b.callContract(ctx, call, b.pendingBlock, b.pendingState)
+		b.pendingState.RevertToSnapshot(snapshot)
+
+		if err != nil || failed {
+			return false
+		}
+		return true
+	}
+	// Execute the binary search and hone in on an executable gas limit
+	for lo+1 < hi {
+		mid := (hi + lo) / 2
+		if !executable(mid) {
+			lo = mid
+		} else {
+			hi = mid
+		}
+	}
+	// Reject the transaction as invalid if it still fails at the highest allowance
+	if hi == cap {
+		if !executable(hi) {
+			return 0, errGasEstimationFailed
+		}
+	}
+	return hi, nil
+}
+
+// callContract implements common code between normal and pending contract calls.
+// state is modified during execution, make sure to copy it if necessary.
+func (b *SimulatedBackend) callContract(ctx context.Context, call ethereum.CallMsg, block *types.Block, statedb *state.StateDB) ([]byte, uint64, bool, error) {
+	// Ensure message is initialized properly.
+	if call.GasPrice == nil {
+		call.GasPrice = big.NewInt(1)
+	}
+	if call.Gas == 0 {
+		call.Gas = 50000000
+	}
+	if call.Value == nil {
+		call.Value = new(big.Int)
+	}
+	// Set infinite balance to the fake caller account.
+	from := statedb.GetOrNewStateObject(call.From)
+	from.SetBalance(math.MaxBig256)
+	// Execute the call.
+	msg := callmsg{call}
+
+	evmContext := core.NewEVMContext(msg, block.Header(), b.blockchain, nil)
+	// Create a new environment which holds all relevant information
+	// about the transaction and calling mechanisms.
+	vmenv := vm.NewEVM(evmContext, statedb, b.config, vm.Config{})
+	gaspool := new(core.GasPool).AddGas(math.MaxUint64)
+
+	return core.NewStateTransition(vmenv, msg, gaspool).TransitionDb()
+}
+
+// SendTransaction updates the pending block to include the given transaction.
+// It panics if the transaction is invalid.
+func (b *SimulatedBackend) SendTransaction(ctx context.Context, tx *types.Transaction) error {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	sender, err := types.Sender(types.NewEIP155Signer(b.config.ChainID), tx)
+	if err != nil {
+		panic(fmt.Errorf("invalid transaction: %v", err))
+	}
+	nonce := b.pendingState.GetNonce(sender)
+	if tx.Nonce() != nonce {
+		panic(fmt.Errorf("invalid transaction nonce: got %d, want %d", tx.Nonce(), nonce))
+	}
+
+	blocks, _ := core.GenerateChain(b.config, b.blockchain.CurrentBlock(), ethash.NewFaker(), b.database, 1, func(number int, block *core.BlockGen) {
+		for _, tx := range b.pendingBlock.Transactions() {
+			block.AddTxWithChain(b.blockchain, tx)
+		}
+		block.AddTxWithChain(b.blockchain, tx)
+	})
+	statedb, _ := b.blockchain.State()
+
+	b.pendingBlock = blocks[0]
+	b.pendingState, _ = state.New(b.pendingBlock.Root(), statedb.Database())
+	return nil
+}
+
+// FilterLogs executes a log filter operation, blocking during execution and
+// returning all the results in one batch.
+//
+// TODO(karalabe): Deprecate when the subscription one can return past data too.
+func (b *SimulatedBackend) FilterLogs(ctx context.Context, query ethereum.FilterQuery) ([]types.Log, error) {
+	var filter *filters.Filter
+	if query.BlockHash != nil {
+		// Block filter requested, construct a single-shot filter
+		filter = filters.NewBlockFilter(&filterBackend{b.database, b.blockchain}, *query.BlockHash, query.Addresses, query.Topics)
+	} else {
+		// Initialize unset filter boundaried to run from genesis to chain head
+		from := int64(0)
+		if query.FromBlock != nil {
+			from = query.FromBlock.Int64()
+		}
+		to := int64(-1)
+		if query.ToBlock != nil {
+			to = query.ToBlock.Int64()
+		}
+		// Construct the range filter
+		filter = filters.NewRangeFilter(&filterBackend{b.database, b.blockchain}, from, to, query.Addresses, query.Topics)
+	}
+	// Run the filter and return all the logs
+	logs, err := filter.Logs(ctx)
+	if err != nil {
+		return nil, err
+	}
+	res := make([]types.Log, len(logs))
+	for i, log := range logs {
+		res[i] = *log
+	}
+	return res, nil
+}
+
+// SubscribeFilterLogs creates a background log filtering operation, returning a
+// subscription immediately, which can be used to stream the found events.
+func (b *SimulatedBackend) SubscribeFilterLogs(ctx context.Context, query ethereum.FilterQuery, ch chan<- types.Log) (ethereum.Subscription, error) {
+	// Subscribe to contract events
+	sink := make(chan []*types.Log)
+
+	sub, err := b.events.SubscribeLogs(query, sink)
+	if err != nil {
+		return nil, err
+	}
+	// Since we're getting logs in batches, we need to flatten them into a plain stream
+	return event.NewSubscription(func(quit <-chan struct{}) error {
+		defer sub.Unsubscribe()
+		for {
+			select {
+			case logs := <-sink:
+				for _, log := range logs {
+					select {
+					case ch <- *log:
+					case err := <-sub.Err():
+						return err
+					case <-quit:
+						return nil
+					}
+				}
+			case err := <-sub.Err():
+				return err
+			case <-quit:
+				return nil
+			}
+		}
+	}), nil
+}
+
+// AdjustTime adds a time shift to the simulated clock.
+func (b *SimulatedBackend) AdjustTime(adjustment time.Duration) error {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	blocks, _ := core.GenerateChain(b.config, b.blockchain.CurrentBlock(), ethash.NewFaker(), b.database, 1, func(number int, block *core.BlockGen) {
+		for _, tx := range b.pendingBlock.Transactions() {
+			block.AddTx(tx)
+		}
+		block.OffsetTime(int64(adjustment.Seconds()))
+	})
+	statedb, _ := b.blockchain.State()
+
+	b.pendingBlock = blocks[0]
+	b.pendingState, _ = state.New(b.pendingBlock.Root(), statedb.Database())
+
+	return nil
+}
+
+// Blockchain returns the underlying blockchain.
+func (b *SimulatedBackend) Blockchain() *core.BlockChain {
+	return b.blockchain
+}
+
+// callmsg implements core.Message to allow passing it as a transaction simulator.
+type callmsg struct {
+	ethereum.CallMsg
+}
+
+func (m callmsg) From() common.Address { return m.CallMsg.From }
+func (m callmsg) Nonce() uint64        { return 0 }
+func (m callmsg) CheckNonce() bool     { return false }
+func (m callmsg) To() *common.Address  { return m.CallMsg.To }
+func (m callmsg) GasPrice() *big.Int   { return m.CallMsg.GasPrice }
+func (m callmsg) Gas() uint64          { return m.CallMsg.Gas }
+func (m callmsg) Value() *big.Int      { return m.CallMsg.Value }
+func (m callmsg) Data() []byte         { return m.CallMsg.Data }
+
+// filterBackend implements filters.Backend to support filtering for logs without
+// taking bloom-bits acceleration structures into account.
+type filterBackend struct {
+	db ethdb.Database
+	bc *core.BlockChain
+}
+
+func (fb *filterBackend) ChainDb() ethdb.Database  { return fb.db }
+func (fb *filterBackend) EventMux() *event.TypeMux { panic("not supported") }
+
+func (fb *filterBackend) HeaderByNumber(ctx context.Context, block rpc.BlockNumber) (*types.Header, error) {
+	if block == rpc.LatestBlockNumber {
+		return fb.bc.CurrentHeader(), nil
+	}
+	return fb.bc.GetHeaderByNumber(uint64(block.Int64())), nil
+}
+
+func (fb *filterBackend) HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error) {
+	return fb.bc.GetHeaderByHash(hash), nil
+}
+
+func (fb *filterBackend) GetReceipts(ctx context.Context, hash common.Hash) (types.Receipts, error) {
+	number := rawdb.ReadHeaderNumber(fb.db, hash)
+	if number == nil {
+		return nil, nil
+	}
+	return rawdb.ReadReceipts(fb.db, hash, *number, fb.bc.Config()), nil
+}
+
+func (fb *filterBackend) GetLogs(ctx context.Context, hash common.Hash) ([][]*types.Log, error) {
+	number := rawdb.ReadHeaderNumber(fb.db, hash)
+	if number == nil {
+		return nil, nil
+	}
+	receipts := rawdb.ReadReceipts(fb.db, hash, *number, fb.bc.Config())
+	if receipts == nil {
+		return nil, nil
+	}
+	logs := make([][]*types.Log, len(receipts))
+	for i, receipt := range receipts {
+		logs[i] = receipt.Logs
+	}
+	return logs, nil
+}
+
+func (fb *filterBackend) SubscribeNewTxsEvent(ch chan<- core.NewTxsEvent) event.Subscription {
+	return event.NewSubscription(func(quit <-chan struct{}) error {
+		<-quit
+		return nil
+	})
+}
+func (fb *filterBackend) SubscribeChainEvent(ch chan<- core.ChainEvent) event.Subscription {
+	return fb.bc.SubscribeChainEvent(ch)
+}
+func (fb *filterBackend) SubscribeRemovedLogsEvent(ch chan<- core.RemovedLogsEvent) event.Subscription {
+	return fb.bc.SubscribeRemovedLogsEvent(ch)
+}
+func (fb *filterBackend) SubscribeLogsEvent(ch chan<- []*types.Log) event.Subscription {
+	return fb.bc.SubscribeLogsEvent(ch)
+}
+
+func (fb *filterBackend) BloomStatus() (uint64, uint64) { return 4096, 0 }
+func (fb *filterBackend) ServiceFilter(ctx context.Context, ms *bloombits.MatcherSession) {
+	panic("not supported")
+}