From 402fd6e8c6a2e379351e0aae10a833fae6bcae6c Mon Sep 17 00:00:00 2001
From: Péter Szilágyi <peterke@gmail.com>
Date: Mon, 12 Oct 2015 15:04:38 +0300
Subject: core, eth, event, miner, xeth: fix event post / subscription race

---
 eth/filters/filter_system.go | 44 ++++++++++++++++++++++++++++----------------
 1 file changed, 28 insertions(+), 16 deletions(-)

(limited to 'eth/filters')

diff --git a/eth/filters/filter_system.go b/eth/filters/filter_system.go
index 4972dcd59..ae6093525 100644
--- a/eth/filters/filter_system.go
+++ b/eth/filters/filter_system.go
@@ -20,6 +20,7 @@ package filters
 
 import (
 	"sync"
+	"time"
 
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/vm"
@@ -35,6 +36,7 @@ type FilterSystem struct {
 	filterMu sync.RWMutex
 	filterId int
 	filters  map[int]*Filter
+	created  map[int]time.Time
 
 	quit chan struct{}
 }
@@ -44,6 +46,7 @@ func NewFilterSystem(mux *event.TypeMux) *FilterSystem {
 	fs := &FilterSystem{
 		eventMux: mux,
 		filters:  make(map[int]*Filter),
+		created:  make(map[int]time.Time),
 	}
 	go fs.filterLoop()
 	return fs
@@ -60,6 +63,7 @@ func (fs *FilterSystem) Add(filter *Filter) (id int) {
 	defer fs.filterMu.Unlock()
 	id = fs.filterId
 	fs.filters[id] = filter
+	fs.created[id] = time.Now()
 	fs.filterId++
 
 	return id
@@ -69,15 +73,16 @@ func (fs *FilterSystem) Add(filter *Filter) (id int) {
 func (fs *FilterSystem) Remove(id int) {
 	fs.filterMu.Lock()
 	defer fs.filterMu.Unlock()
-	if _, ok := fs.filters[id]; ok {
-		delete(fs.filters, id)
-	}
+
+	delete(fs.filters, id)
+	delete(fs.created, 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]
 }
 
@@ -85,42 +90,49 @@ func (fs *FilterSystem) Get(id int) *Filter {
 // when the filter matches the requirements.
 func (fs *FilterSystem) filterLoop() {
 	// Subscribe to events
-	events := fs.eventMux.Subscribe(
+	eventCh := fs.eventMux.Subscribe(
 		//core.PendingBlockEvent{},
 		core.ChainEvent{},
 		core.TxPreEvent{},
-		vm.Logs(nil))
+		vm.Logs(nil),
+	).Chan()
 
 out:
 	for {
 		select {
 		case <-fs.quit:
 			break out
-		case event := <-events.Chan():
-			switch event := event.(type) {
+		case event, ok := <-eventCh:
+			if !ok {
+				// Event subscription closed, set the channel to nil to stop spinning
+				eventCh = nil
+				continue
+			}
+			// A real event arrived, notify the registered filters
+			switch ev := event.Data.(type) {
 			case core.ChainEvent:
 				fs.filterMu.RLock()
-				for _, filter := range fs.filters {
-					if filter.BlockCallback != nil {
-						filter.BlockCallback(event.Block, event.Logs)
+				for id, filter := range fs.filters {
+					if filter.BlockCallback != nil && fs.created[id].Before(event.Time) {
+						filter.BlockCallback(ev.Block, ev.Logs)
 					}
 				}
 				fs.filterMu.RUnlock()
 
 			case core.TxPreEvent:
 				fs.filterMu.RLock()
-				for _, filter := range fs.filters {
-					if filter.TransactionCallback != nil {
-						filter.TransactionCallback(event.Tx)
+				for id, filter := range fs.filters {
+					if filter.TransactionCallback != nil && fs.created[id].Before(event.Time) {
+						filter.TransactionCallback(ev.Tx)
 					}
 				}
 				fs.filterMu.RUnlock()
 
 			case vm.Logs:
 				fs.filterMu.RLock()
-				for _, filter := range fs.filters {
-					if filter.LogsCallback != nil {
-						msgs := filter.FilterLogs(event)
+				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)
 						}
-- 
cgit