eth/filters: ✨ pending logs ✨

Pending logs are now filterable through the Go API. Filter API changed
such that each filter type has it's own bucket and adding filter
explicitly requires you specify the bucket to put it in.

4 files changed, 119 insertions, 40 deletions

diff --git a/eth/filters/api.go b/eth/filters/api.go
index 148daa649..6cd184b80 100644
--- a/eth/filters/api.go
+++ b/eth/filters/api.go
@@ -142,7 +142,11 @@ func (s *PublicFilterAPI) NewBlockFilter() (string, error) {
 
 	s.blockMu.Lock()
 	filter := New(s.chainDb)
-	id := s.filterManager.Add(filter)
+	id, err := s.filterManager.Add(filter, ChainFilter)
+	if err != nil {
+		return "", err
+	}
+
 	s.blockQueue[id] = &hashQueue{timeout: time.Now()}
 
 	filter.BlockCallback = func(block *types.Block, logs vm.Logs) {
@@ -174,7 +178,11 @@ func (s *PublicFilterAPI) NewPendingTransactionFilter() (string, error) {
 	defer s.transactionMu.Unlock()
 
 	filter := New(s.chainDb)
-	id := s.filterManager.Add(filter)
+	id, err := s.filterManager.Add(filter, PendingTxFilter)
+	if err != nil {
+		return "", err
+	}
+
 	s.transactionQueue[id] = &hashQueue{timeout: time.Now()}
 
 	filter.TransactionCallback = func(tx *types.Transaction) {
@@ -194,12 +202,16 @@ func (s *PublicFilterAPI) NewPendingTransactionFilter() (string, error) {
 }
 
 // newLogFilter creates a new log filter.
-func (s *PublicFilterAPI) newLogFilter(earliest, latest int64, addresses []common.Address, topics [][]common.Hash) int {
+func (s *PublicFilterAPI) newLogFilter(earliest, latest int64, addresses []common.Address, topics [][]common.Hash) (int, error) {
 	s.logMu.Lock()
 	defer s.logMu.Unlock()
 
 	filter := New(s.chainDb)
-	id := s.filterManager.Add(filter)
+	id, err := s.filterManager.Add(filter, LogFilter)
+	if err != nil {
+		return 0, err
+	}
+
 	s.logQueue[id] = &logQueue{timeout: time.Now()}
 
 	filter.SetBeginBlock(earliest)
@@ -215,7 +227,7 @@ func (s *PublicFilterAPI) newLogFilter(earliest, latest int64, addresses []commo
 		}
 	}
 
-	return id
+	return id, nil
 }
 
 // NewFilterArgs represents a request to create a new filter.
@@ -352,9 +364,12 @@ func (s *PublicFilterAPI) NewFilter(args NewFilterArgs) (string, error) {
 
 	var id int
 	if len(args.Addresses) > 0 {
-		id = s.newLogFilter(args.FromBlock.Int64(), args.ToBlock.Int64(), args.Addresses, args.Topics)
+		id, err = s.newLogFilter(args.FromBlock.Int64(), args.ToBlock.Int64(), args.Addresses, args.Topics)
 	} else {
-		id = s.newLogFilter(args.FromBlock.Int64(), args.ToBlock.Int64(), nil, args.Topics)
+		id, err = s.newLogFilter(args.FromBlock.Int64(), args.ToBlock.Int64(), nil, args.Topics)
+	}
+	if err != nil {
+		return "", err
 	}
 
 	s.filterMapMu.Lock()
diff --git a/eth/filters/filter.go b/eth/filters/filter.go
index 2c92d20b1..96af93c4a 100644
--- a/eth/filters/filter.go
+++ b/eth/filters/filter.go
@@ -18,6 +18,7 @@ package filters
 
 import (
 	"math"
+	"time"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core"
@@ -32,6 +33,8 @@ type AccountChange struct {
 
 // Filtering interface
 type Filter struct {
+	created time.Time
+
 	db         ethdb.Database
 	begin, end int64
 	addresses  []common.Address
diff --git a/eth/filters/filter_system.go b/eth/filters/filter_system.go
index 04e58a08c..b61a493b6 100644
--- a/eth/filters/filter_system.go
+++ b/eth/filters/filter_system.go
@@ -19,6 +19,7 @@
 package filters
 
 import (
+	"fmt"
 	"sync"
 	"time"
 
@@ -27,26 +28,47 @@ import (
 	"github.com/ethereum/go-ethereum/event"
 )
 
+// FilterType determines the type of filter and is used to put the filter in to
+// the correct bucket when added.
+type FilterType byte
+
+const (
+	ChainFilter      FilterType = iota // new block events filter
+	PendingTxFilter                    // pending transaction filter
+	LogFilter                          // new or removed log filter
+	PendingLogFilter                   // pending log filter
+)
+
 // FilterSystem manages filters that filter specific events such as
 // block, transaction and log events. The Filtering system can be used to listen
 // for specific LOG events fired by the EVM (Ethereum Virtual Machine).
 type FilterSystem struct {
 	filterMu sync.RWMutex
 	filterId int
-	filters  map[int]*Filter
-	created  map[int]time.Time
-	sub      event.Subscription
+
+	chainFilters      map[int]*Filter
+	pendingTxFilters  map[int]*Filter
+	logFilters        map[int]*Filter
+	pendingLogFilters map[int]*Filter
+
+	// generic is an ugly hack for Get
+	generic map[int]*Filter
+
+	sub event.Subscription
 }
 
 // NewFilterSystem returns a newly allocated filter manager
 func NewFilterSystem(mux *event.TypeMux) *FilterSystem {
 	fs := &FilterSystem{
-		filters: make(map[int]*Filter),
-		created: make(map[int]time.Time),
+		chainFilters:      make(map[int]*Filter),
+		pendingTxFilters:  make(map[int]*Filter),
+		logFilters:        make(map[int]*Filter),
+		pendingLogFilters: make(map[int]*Filter),
+		generic:           make(map[int]*Filter),
 	}
 	fs.sub = mux.Subscribe(
-		//core.PendingBlockEvent{},
-		core.RemovedLogEvent{},
+		core.PendingLogsEvent{},
+		core.RemovedLogsEvent{},
 		core.ChainEvent{},
 		core.TxPreEvent{},
 		vm.Logs(nil),
@@ -61,15 +83,30 @@ func (fs *FilterSystem) Stop() {
 }
 
 // Add adds a filter to the filter manager
-func (fs *FilterSystem) Add(filter *Filter) (id int) {
+func (fs *FilterSystem) Add(filter *Filter, filterType FilterType) (int, error) {
 	fs.filterMu.Lock()
 	defer fs.filterMu.Unlock()
-	id = fs.filterId
-	fs.filters[id] = filter
-	fs.created[id] = time.Now()
+
+	id := fs.filterId
+	filter.created = time.Now()
+
+	switch filterType {
+	case ChainFilter:
+		fs.chainFilters[id] = filter
+	case PendingTxFilter:
+		fs.pendingTxFilters[id] = filter
+	case LogFilter:
+		fs.logFilters[id] = filter
+	case PendingLogFilter:
+		fs.pendingLogFilters[id] = filter
+	default:
+		return 0, fmt.Errorf("unknown filter type %v", filterType)
+	}
+	fs.generic[id] = filter
+
 	fs.filterId++
 
-	return id
+	return id, nil
 }
 
 // Remove removes a filter by filter id
@@ -77,16 +114,18 @@ func (fs *FilterSystem) Remove(id int) {
 	fs.filterMu.Lock()
 	defer fs.filterMu.Unlock()
 
-	delete(fs.filters, id)
-	delete(fs.created, id)
+	delete(fs.chainFilters, id)
+	delete(fs.pendingTxFilters, id)
+	delete(fs.logFilters, id)
+	delete(fs.pendingLogFilters, id)
+	delete(fs.generic, id)
 }
 
-// Get retrieves a filter installed using Add The filter may not be modified.
 func (fs *FilterSystem) Get(id int) *Filter {
 	fs.filterMu.RLock()
 	defer fs.filterMu.RUnlock()
 
-	return fs.filters[id]
+	return fs.generic[id]
 }
 
 // filterLoop waits for specific events from ethereum and fires their handlers
@@ -96,17 +135,16 @@ func (fs *FilterSystem) filterLoop() {
 		switch ev := event.Data.(type) {
 		case core.ChainEvent:
 			fs.filterMu.RLock()
-			for id, filter := range fs.filters {
-				if filter.BlockCallback != nil && !fs.created[id].After(event.Time) {
+			for _, filter := range fs.chainFilters {
+				if filter.BlockCallback != nil && !filter.created.After(event.Time) {
 					filter.BlockCallback(ev.Block, ev.Logs)
 				}
 			}
 			fs.filterMu.RUnlock()
-
 		case core.TxPreEvent:
 			fs.filterMu.RLock()
-			for id, filter := range fs.filters {
-				if filter.TransactionCallback != nil && !fs.created[id].After(event.Time) {
+			for _, filter := range fs.pendingTxFilters {
+				if filter.TransactionCallback != nil && !filter.created.After(event.Time) {
 					filter.TransactionCallback(ev.Tx)
 				}
 			}
@@ -114,25 +152,34 @@ func (fs *FilterSystem) filterLoop() {
 
 		case vm.Logs:
 			fs.filterMu.RLock()
-			for id, filter := range fs.filters {
-				if filter.LogCallback != nil && !fs.created[id].After(event.Time) {
+			for _, filter := range fs.logFilters {
+				if filter.LogCallback != nil && !filter.created.After(event.Time) {
 					for _, log := range filter.FilterLogs(ev) {
 						filter.LogCallback(log, false)
 					}
 				}
 			}
 			fs.filterMu.RUnlock()
-
-		case core.RemovedLogEvent:
+		case core.RemovedLogsEvent:
 			fs.filterMu.RLock()
-			for id, filter := range fs.filters {
-				if filter.LogCallback != nil && !fs.created[id].After(event.Time) {
+			for _, filter := range fs.logFilters {
+				if filter.LogCallback != nil && !filter.created.After(event.Time) {
 					for _, removedLog := range ev.Logs {
 						filter.LogCallback(removedLog, true)
 					}
 				}
 			}
 			fs.filterMu.RUnlock()
+		case core.PendingLogsEvent:
+			fs.filterMu.RLock()
+			for _, filter := range fs.pendingLogFilters {
+				if filter.LogCallback != nil && !filter.created.After(event.Time) {
+					for _, pendingLog := range ev.Logs {
+						filter.LogCallback(pendingLog, false)
+					}
+				}
+			}
+			fs.filterMu.RUnlock()
 		}
 	}
 }
diff --git a/eth/filters/filter_system_test.go b/eth/filters/filter_system_test.go
index 7ddeb02bc..3ad7dd9cb 100644
--- a/eth/filters/filter_system_test.go
+++ b/eth/filters/filter_system_test.go
@@ -18,6 +18,7 @@ func TestCallbacks(t *testing.T) {
 		txDone         = make(chan struct{})
 		logDone        = make(chan struct{})
 		removedLogDone = make(chan struct{})
+		pendingLogDone = make(chan struct{})
 	)
 
 	blockFilter := &Filter{
@@ -37,7 +38,6 @@ func TestCallbacks(t *testing.T) {
 			}
 		},
 	}
-
 	removedLogFilter := &Filter{
 		LogCallback: func(l *vm.Log, oob bool) {
 			if oob {
@@ -45,16 +45,23 @@ func TestCallbacks(t *testing.T) {
 			}
 		},
 	}
+	pendingLogFilter := &Filter{
+		LogCallback: func(*vm.Log, bool) {
+			close(pendingLogDone)
+		},
+	}
 
-	fs.Add(blockFilter)
-	fs.Add(txFilter)
-	fs.Add(logFilter)
-	fs.Add(removedLogFilter)
+	fs.Add(blockFilter, ChainFilter)
+	fs.Add(txFilter, PendingTxFilter)
+	fs.Add(logFilter, LogFilter)
+	fs.Add(removedLogFilter, LogFilter)
+	fs.Add(pendingLogFilter, PendingLogFilter)
 
 	mux.Post(core.ChainEvent{})
 	mux.Post(core.TxPreEvent{})
-	mux.Post(core.RemovedLogEvent{vm.Logs{&vm.Log{}}})
 	mux.Post(vm.Logs{&vm.Log{}})
+	mux.Post(core.RemovedLogsEvent{vm.Logs{&vm.Log{}}})
+	mux.Post(core.PendingLogsEvent{vm.Logs{&vm.Log{}}})
 
 	const dura = 5 * time.Second
 	failTimer := time.NewTimer(dura)
@@ -84,4 +91,11 @@ func TestCallbacks(t *testing.T) {
 	case <-failTimer.C:
 		t.Error("removed log filter failed to trigger (timeout)")
 	}
+
+	failTimer.Reset(dura)
+	select {
+	case <-pendingLogDone:
+	case <-failTimer.C:
+		t.Error("pending log filter failed to trigger (timout)")
+	}
 }