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Merge pull request ethereum#15832 from karalabe/abigen-events
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accounts/abi/bind: support event filtering in abigen
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karalabe authored Jan 24, 2018
2 parents 05ade19 + 1bf508b commit 5c83a4e
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Showing 25 changed files with 2,524 additions and 1,463 deletions.
1 change: 0 additions & 1 deletion accounts/abi/abi.go
Original file line number Diff line number Diff line change
Expand Up @@ -97,7 +97,6 @@ func (abi *ABI) UnmarshalJSON(data []byte) error {
Type string
Name string
Constant bool
Indexed bool
Anonymous bool
Inputs []Argument
Outputs []Argument
Expand Down
27 changes: 21 additions & 6 deletions accounts/abi/bind/backend.go
Original file line number Diff line number Diff line change
Expand Up @@ -52,12 +52,6 @@ type ContractCaller interface {
CallContract(ctx context.Context, call ethereum.CallMsg, blockNumber *big.Int) ([]byte, error)
}

// DeployBackend wraps the operations needed by WaitMined and WaitDeployed.
type DeployBackend interface {
TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error)
CodeAt(ctx context.Context, account common.Address, blockNumber *big.Int) ([]byte, error)
}

// PendingContractCaller defines methods to perform contract calls on the pending state.
// Call will try to discover this interface when access to the pending state is requested.
// If the backend does not support the pending state, Call returns ErrNoPendingState.
Expand Down Expand Up @@ -90,8 +84,29 @@ type ContractTransactor interface {
SendTransaction(ctx context.Context, tx *types.Transaction) error
}

// ContractFilterer defines the methods needed to access log events using one-off
// queries or continuous event subscriptions.
type ContractFilterer interface {
// 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.
FilterLogs(ctx context.Context, query ethereum.FilterQuery) ([]types.Log, error)

// SubscribeFilterLogs creates a background log filtering operation, returning
// a subscription immediately, which can be used to stream the found events.
SubscribeFilterLogs(ctx context.Context, query ethereum.FilterQuery, ch chan<- types.Log) (ethereum.Subscription, error)
}

// DeployBackend wraps the operations needed by WaitMined and WaitDeployed.
type DeployBackend interface {
TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error)
CodeAt(ctx context.Context, account common.Address, blockNumber *big.Int) ([]byte, error)
}

// ContractBackend defines the methods needed to work with contracts on a read-write basis.
type ContractBackend interface {
ContractCaller
ContractTransactor
ContractFilterer
}
121 changes: 118 additions & 3 deletions accounts/abi/bind/backends/simulated.go
Original file line number Diff line number Diff line change
Expand Up @@ -30,11 +30,15 @@ import (
"github.com/ethereum/go-ethereum/common/math"
"github.com/ethereum/go-ethereum/consensus/ethash"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/bloombits"
"github.com/ethereum/go-ethereum/core/state"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/core/vm"
"github.com/ethereum/go-ethereum/eth/filters"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/params"
"github.com/ethereum/go-ethereum/rpc"
)

// This nil assignment ensures compile time that SimulatedBackend implements bind.ContractBackend.
Expand All @@ -53,6 +57,8 @@ type SimulatedBackend struct {
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
}

Expand All @@ -63,7 +69,13 @@ func NewSimulatedBackend(alloc core.GenesisAlloc) *SimulatedBackend {
genesis := core.Genesis{Config: params.AllEthashProtocolChanges, Alloc: alloc}
genesis.MustCommit(database)
blockchain, _ := core.NewBlockChain(database, genesis.Config, ethash.NewFaker(), vm.Config{})
backend := &SimulatedBackend{database: database, blockchain: blockchain, config: genesis.Config}

backend := &SimulatedBackend{
database: database,
blockchain: blockchain,
config: genesis.Config,
events: filters.NewEventSystem(new(event.TypeMux), &filterBackend{database, blockchain}, false),
}
backend.rollback()
return backend
}
Expand Down Expand Up @@ -248,7 +260,7 @@ func (b *SimulatedBackend) EstimateGas(ctx context.Context, call ethereum.CallMs
return hi, nil
}

// callContract implemens common code between normal and pending contract calls.
// 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.
Expand Down Expand Up @@ -302,7 +314,69 @@ func (b *SimulatedBackend) SendTransaction(ctx context.Context, tx *types.Transa
return nil
}

// JumpTimeInSeconds adds skip seconds to the clock
// 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) {
// 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 and execute the filter
filter := filters.New(&filterBackend{b.database, b.blockchain}, from, to, query.Addresses, query.Topics)

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()
Expand Down Expand Up @@ -331,3 +405,44 @@ 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) GetReceipts(ctx context.Context, hash common.Hash) (types.Receipts, error) {
return core.GetBlockReceipts(fb.db, hash, core.GetBlockNumber(fb.db, hash)), nil
}

func (fb *filterBackend) SubscribeTxPreEvent(ch chan<- core.TxPreEvent) 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")
}
121 changes: 119 additions & 2 deletions accounts/abi/bind/base.go
Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@ import (
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/event"
)

// SignerFn is a signer function callback when a contract requires a method to
Expand Down Expand Up @@ -55,6 +56,22 @@ type TransactOpts struct {
Context context.Context // Network context to support cancellation and timeouts (nil = no timeout)
}

// FilterOpts is the collection of options to fine tune filtering for events
// within a bound contract.
type FilterOpts struct {
Start uint64 // Start of the queried range
End *uint64 // End of the range (nil = latest)

Context context.Context // Network context to support cancellation and timeouts (nil = no timeout)
}

// WatchOpts is the collection of options to fine tune subscribing for events
// within a bound contract.
type WatchOpts struct {
Start *uint64 // Start of the queried range (nil = latest)
Context context.Context // Network context to support cancellation and timeouts (nil = no timeout)
}

// BoundContract is the base wrapper object that reflects a contract on the
// Ethereum network. It contains a collection of methods that are used by the
// higher level contract bindings to operate.
Expand All @@ -63,24 +80,26 @@ type BoundContract struct {
abi abi.ABI // Reflect based ABI to access the correct Ethereum methods
caller ContractCaller // Read interface to interact with the blockchain
transactor ContractTransactor // Write interface to interact with the blockchain
filterer ContractFilterer // Event filtering to interact with the blockchain
}

// NewBoundContract creates a low level contract interface through which calls
// and transactions may be made through.
func NewBoundContract(address common.Address, abi abi.ABI, caller ContractCaller, transactor ContractTransactor) *BoundContract {
func NewBoundContract(address common.Address, abi abi.ABI, caller ContractCaller, transactor ContractTransactor, filterer ContractFilterer) *BoundContract {
return &BoundContract{
address: address,
abi: abi,
caller: caller,
transactor: transactor,
filterer: filterer,
}
}

// DeployContract deploys a contract onto the Ethereum blockchain and binds the
// deployment address with a Go wrapper.
func DeployContract(opts *TransactOpts, abi abi.ABI, bytecode []byte, backend ContractBackend, params ...interface{}) (common.Address, *types.Transaction, *BoundContract, error) {
// Otherwise try to deploy the contract
c := NewBoundContract(common.Address{}, abi, backend, backend)
c := NewBoundContract(common.Address{}, abi, backend, backend, backend)

input, err := c.abi.Pack("", params...)
if err != nil {
Expand Down Expand Up @@ -225,6 +244,104 @@ func (c *BoundContract) transact(opts *TransactOpts, contract *common.Address, i
return signedTx, nil
}

// FilterLogs filters contract logs for past blocks, returning the necessary
// channels to construct a strongly typed bound iterator on top of them.
func (c *BoundContract) FilterLogs(opts *FilterOpts, name string, query ...[]interface{}) (chan types.Log, event.Subscription, error) {
// Don't crash on a lazy user
if opts == nil {
opts = new(FilterOpts)
}
// Append the event selector to the query parameters and construct the topic set
query = append([][]interface{}{{c.abi.Events[name].Id()}}, query...)

topics, err := makeTopics(query...)
if err != nil {
return nil, nil, err
}
// Start the background filtering
logs := make(chan types.Log, 128)

config := ethereum.FilterQuery{
Addresses: []common.Address{c.address},
Topics: topics,
FromBlock: new(big.Int).SetUint64(opts.Start),
}
if opts.End != nil {
config.ToBlock = new(big.Int).SetUint64(*opts.End)
}
/* TODO(karalabe): Replace the rest of the method below with this when supported
sub, err := c.filterer.SubscribeFilterLogs(ensureContext(opts.Context), config, logs)
*/
buff, err := c.filterer.FilterLogs(ensureContext(opts.Context), config)
if err != nil {
return nil, nil, err
}
sub, err := event.NewSubscription(func(quit <-chan struct{}) error {
for _, log := range buff {
select {
case logs <- log:
case <-quit:
return nil
}
}
return nil
}), nil

if err != nil {
return nil, nil, err
}
return logs, sub, nil
}

// WatchLogs filters subscribes to contract logs for future blocks, returning a
// subscription object that can be used to tear down the watcher.
func (c *BoundContract) WatchLogs(opts *WatchOpts, name string, query ...[]interface{}) (chan types.Log, event.Subscription, error) {
// Don't crash on a lazy user
if opts == nil {
opts = new(WatchOpts)
}
// Append the event selector to the query parameters and construct the topic set
query = append([][]interface{}{{c.abi.Events[name].Id()}}, query...)

topics, err := makeTopics(query...)
if err != nil {
return nil, nil, err
}
// Start the background filtering
logs := make(chan types.Log, 128)

config := ethereum.FilterQuery{
Addresses: []common.Address{c.address},
Topics: topics,
}
if opts.Start != nil {
config.FromBlock = new(big.Int).SetUint64(*opts.Start)
}
sub, err := c.filterer.SubscribeFilterLogs(ensureContext(opts.Context), config, logs)
if err != nil {
return nil, nil, err
}
return logs, sub, nil
}

// UnpackLog unpacks a retrieved log into the provided output structure.
func (c *BoundContract) UnpackLog(out interface{}, event string, log types.Log) error {
if len(log.Data) > 0 {
if err := c.abi.Unpack(out, event, log.Data); err != nil {
return err
}
}
var indexed abi.Arguments
for _, arg := range c.abi.Events[event].Inputs {
if arg.Indexed {
indexed = append(indexed, arg)
}
}
return parseTopics(out, indexed, log.Topics[1:])
}

// ensureContext is a helper method to ensure a context is not nil, even if the
// user specified it as such.
func ensureContext(ctx context.Context) context.Context {
if ctx == nil {
return context.TODO()
Expand Down
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