eth/filters: added notifications for out of bound log events

Out of Bound log events are events that were removed due to a fork. When
logs are received the filtering mechanism should check for the `removed`
field on the json structure.

eth/filters/api.go

@@ -206,12 +206,12 @@ func (s *PublicFilterAPI) newLogFilter(earliest, latest int64, addresses []commo
 	filter.SetEndBlock(latest)
 	filter.SetAddresses(addresses)
 	filter.SetTopics(topics)
-	filter.LogsCallback = func(logs vm.Logs) {
+	filter.LogCallback = func(log *vm.Log, removed bool) {
 		s.logMu.Lock()
 		defer s.logMu.Unlock()
 
 		if queue := s.logQueue[id]; queue != nil {
-			queue.add(logs...)
+			queue.add(vmlog{log, removed})
 		}
 	}
 
@@ -365,14 +365,14 @@ func (s *PublicFilterAPI) NewFilter(args NewFilterArgs) (string, error) {
 }
 
 // GetLogs returns the logs matching the given argument.
-func (s *PublicFilterAPI) GetLogs(args NewFilterArgs) vm.Logs {
+func (s *PublicFilterAPI) GetLogs(args NewFilterArgs) []vmlog {
 	filter := New(s.chainDb)
 	filter.SetBeginBlock(args.FromBlock.Int64())
 	filter.SetEndBlock(args.ToBlock.Int64())
 	filter.SetAddresses(args.Addresses)
 	filter.SetTopics(args.Topics)
 
-	return returnLogs(filter.Find())
+	return toRPCLogs(filter.Find(), false)
 }
 
 // UninstallFilter removes the filter with the given filter id.
@@ -447,7 +447,7 @@ func (s *PublicFilterAPI) transactionFilterChanged(id int) []common.Hash {
 }
 
 // logFilterChanged returns a collection of logs for the log filter with the given id.
-func (s *PublicFilterAPI) logFilterChanged(id int) vm.Logs {
+func (s *PublicFilterAPI) logFilterChanged(id int) []vmlog {
 	s.logMu.Lock()
 	defer s.logMu.Unlock()
 
@@ -458,17 +458,17 @@ func (s *PublicFilterAPI) logFilterChanged(id int) vm.Logs {
 }
 
 // GetFilterLogs returns the logs for the filter with the given id.
-func (s *PublicFilterAPI) GetFilterLogs(filterId string) vm.Logs {
+func (s *PublicFilterAPI) GetFilterLogs(filterId string) []vmlog {
 	id, ok := s.filterMapping[filterId]
 	if !ok {
-		return returnLogs(nil)
+		return toRPCLogs(nil, false)
 	}
 
 	if filter := s.filterManager.Get(id); filter != nil {
-		return returnLogs(filter.Find())
+		return toRPCLogs(filter.Find(), false)
 	}
 
-	return returnLogs(nil)
+	return toRPCLogs(nil, false)
 }
 
 // GetFilterChanges returns the logs for the filter with the given id since last time is was called.
@@ -488,28 +488,33 @@ func (s *PublicFilterAPI) GetFilterChanges(filterId string) interface{} {
 	case transactionFilterTy:
 		return returnHashes(s.transactionFilterChanged(id))
 	case logFilterTy:
-		return returnLogs(s.logFilterChanged(id))
+		return s.logFilterChanged(id)
 	}
 
 	return []interface{}{}
 }
 
+type vmlog struct {
+	*vm.Log
+	Removed bool `json:"removed"`
+}
+
 type logQueue struct {
 	mu sync.Mutex
 
-	logs    vm.Logs
+	logs    []vmlog
 	timeout time.Time
 	id      int
 }
 
-func (l *logQueue) add(logs ...*vm.Log) {
+func (l *logQueue) add(logs ...vmlog) {
 	l.mu.Lock()
 	defer l.mu.Unlock()
 
 	l.logs = append(l.logs, logs...)
 }
 
-func (l *logQueue) get() vm.Logs {
+func (l *logQueue) get() []vmlog {
 	l.mu.Lock()
 	defer l.mu.Unlock()
 
@@ -556,13 +561,16 @@ func newFilterId() (string, error) {
 	return "0x" + hex.EncodeToString(subid[:]), nil
 }
 
-// returnLogs is a helper that will return an empty logs array case the given logs is nil, otherwise is will return the
-// given logs. The RPC interfaces defines that always an array is returned.
-func returnLogs(logs vm.Logs) vm.Logs {
-	if logs == nil {
-		return vm.Logs{}
+// toRPCLogs is a helper that will convert a vm.Logs array to an structure which
+// can hold additional information about the logs such as whether it was deleted.
+// Additionally when nil is given it will by default instead create an empty slice
+// instead. This is required by the RPC specification.
+func toRPCLogs(logs vm.Logs, removed bool) []vmlog {
+	convertedLogs := make([]vmlog, len(logs))
+	for i, log := range logs {
+		convertedLogs[i] = vmlog{Log: log, Removed: removed}
 	}
-	return logs
+	return convertedLogs
 }
 
 // returnHashes is a helper that will return an empty hash array case the given hash array is nil, otherwise is will

eth/filters/filter.go

@@ -39,7 +39,7 @@ type Filter struct {
 
 	BlockCallback       func(*types.Block, vm.Logs)
 	TransactionCallback func(*types.Transaction)
-	LogsCallback        func(vm.Logs)
+	LogCallback         func(*vm.Log, bool)
 }
 
 // Create a new filter which uses a bloom filter on blocks to figure out whether a particular block

eth/filters/filter_system.go

@@ -46,6 +46,7 @@ func NewFilterSystem(mux *event.TypeMux) *FilterSystem {
 	}
 	fs.sub = mux.Subscribe(
 		//core.PendingBlockEvent{},
+		core.RemovedLogEvent{},
 		core.ChainEvent{},
 		core.TxPreEvent{},
 		vm.Logs(nil),
@@ -96,7 +97,7 @@ func (fs *FilterSystem) filterLoop() {
 		case core.ChainEvent:
 			fs.filterMu.RLock()
 			for id, filter := range fs.filters {
-				if filter.BlockCallback != nil && fs.created[id].Before(event.Time) {
+				if filter.BlockCallback != nil && !fs.created[id].After(event.Time) {
 					filter.BlockCallback(ev.Block, ev.Logs)
 				}
 			}
@@ -105,7 +106,7 @@ func (fs *FilterSystem) filterLoop() {
 		case core.TxPreEvent:
 			fs.filterMu.RLock()
 			for id, filter := range fs.filters {
-				if filter.TransactionCallback != nil && fs.created[id].Before(event.Time) {
+				if filter.TransactionCallback != nil && !fs.created[id].After(event.Time) {
 					filter.TransactionCallback(ev.Tx)
 				}
 			}
@@ -114,10 +115,20 @@ func (fs *FilterSystem) filterLoop() {
 		case vm.Logs:
 			fs.filterMu.RLock()
 			for id, filter := range fs.filters {
-				if filter.LogsCallback != nil && fs.created[id].Before(event.Time) {
-					msgs := filter.FilterLogs(ev)
-					if len(msgs) > 0 {
-						filter.LogsCallback(msgs)
+				if filter.LogCallback != nil && !fs.created[id].After(event.Time) {
+					for _, log := range filter.FilterLogs(ev) {
+						filter.LogCallback(log, false)
+					}
+				}
+			}
+			fs.filterMu.RUnlock()
+
+		case core.RemovedLogEvent:
+			fs.filterMu.RLock()
+			for id, filter := range fs.filters {
+				if filter.LogCallback != nil && !fs.created[id].After(event.Time) {
+					for _, removedLog := range ev.Logs {
+						filter.LogCallback(removedLog, true)
 					}
 				}
 			}

eth/filters/filter_system_test.go

@@ -0,0 +1,87 @@
+package filters
+
+import (
+	"testing"
+	"time"
+
+	"github.com/ethereum/go-ethereum/core"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/core/vm"
+	"github.com/ethereum/go-ethereum/event"
+)
+
+func TestCallbacks(t *testing.T) {
+	var (
+		mux            event.TypeMux
+		fs             = NewFilterSystem(&mux)
+		blockDone      = make(chan struct{})
+		txDone         = make(chan struct{})
+		logDone        = make(chan struct{})
+		removedLogDone = make(chan struct{})
+	)
+
+	blockFilter := &Filter{
+		BlockCallback: func(*types.Block, vm.Logs) {
+			close(blockDone)
+		},
+	}
+	txFilter := &Filter{
+		TransactionCallback: func(*types.Transaction) {
+			close(txDone)
+		},
+	}
+	logFilter := &Filter{
+		LogCallback: func(l *vm.Log, oob bool) {
+			if !oob {
+				close(logDone)
+			}
+		},
+	}
+
+	removedLogFilter := &Filter{
+		LogCallback: func(l *vm.Log, oob bool) {
+			if oob {
+				close(removedLogDone)
+			}
+		},
+	}
+
+	fs.Add(blockFilter)
+	fs.Add(txFilter)
+	fs.Add(logFilter)
+	fs.Add(removedLogFilter)
+
+	mux.Post(core.ChainEvent{})
+	mux.Post(core.TxPreEvent{})
+	mux.Post(core.RemovedLogEvent{vm.Logs{&vm.Log{}}})
+	mux.Post(vm.Logs{&vm.Log{}})
+
+	const dura = 5 * time.Second
+	failTimer := time.NewTimer(dura)
+	select {
+	case <-blockDone:
+	case <-failTimer.C:
+		t.Error("block filter failed to trigger (timeout)")
+	}
+
+	failTimer.Reset(dura)
+	select {
+	case <-txDone:
+	case <-failTimer.C:
+		t.Error("transaction filter failed to trigger (timeout)")
+	}
+
+	failTimer.Reset(dura)
+	select {
+	case <-logDone:
+	case <-failTimer.C:
+		t.Error("log filter failed to trigger (timeout)")
+	}
+
+	failTimer.Reset(dura)
+	select {
+	case <-removedLogDone:
+	case <-failTimer.C:
+		t.Error("removed log filter failed to trigger (timeout)")
+	}
+}