Merge pull request #1852 from obscuren/filter-nil-fix

xeth: fixed nil pointer of filter retrieval

xeth/xeth.go

@@ -532,8 +532,10 @@ func (self *XEth) NewLogFilter(earliest, latest int64, skip, max int, address []
 	self.logMu.Lock()
 	defer self.logMu.Unlock()
 
-	var id int
 	filter := core.NewFilter(self.backend)
+	id := self.filterManager.InstallFilter(filter)
+	self.logQueue[id] = &logQueue{timeout: time.Now()}
+
 	filter.SetEarliestBlock(earliest)
 	filter.SetLatestBlock(latest)
 	filter.SetSkip(skip)
@@ -544,10 +546,10 @@ func (self *XEth) NewLogFilter(earliest, latest int64, skip, max int, address []
 		self.logMu.Lock()
 		defer self.logMu.Unlock()
 
-		self.logQueue[id].add(logs...)
+		if queue := self.logQueue[id]; queue != nil {
+			queue.add(logs...)
+		}
 	}
-	id = self.filterManager.InstallFilter(filter)
-	self.logQueue[id] = &logQueue{timeout: time.Now()}
 
 	return id
 }
@@ -556,16 +558,18 @@ func (self *XEth) NewTransactionFilter() int {
 	self.transactionMu.Lock()
 	defer self.transactionMu.Unlock()
 
-	var id int
 	filter := core.NewFilter(self.backend)
+	id := self.filterManager.InstallFilter(filter)
+	self.transactionQueue[id] = &hashQueue{timeout: time.Now()}
+
 	filter.TransactionCallback = func(tx *types.Transaction) {
 		self.transactionMu.Lock()
 		defer self.transactionMu.Unlock()
 
-		self.transactionQueue[id].add(tx.Hash())
+		if queue := self.transactionQueue[id]; queue != nil {
+			queue.add(tx.Hash())
+		}
 	}
-	id = self.filterManager.InstallFilter(filter)
-	self.transactionQueue[id] = &hashQueue{timeout: time.Now()}
 	return id
 }
 
@@ -573,16 +577,18 @@ func (self *XEth) NewBlockFilter() int {
 	self.blockMu.Lock()
 	defer self.blockMu.Unlock()
 
-	var id int
 	filter := core.NewFilter(self.backend)
+	id := self.filterManager.InstallFilter(filter)
+	self.blockQueue[id] = &hashQueue{timeout: time.Now()}
+
 	filter.BlockCallback = func(block *types.Block, logs state.Logs) {
 		self.blockMu.Lock()
 		defer self.blockMu.Unlock()
 
-		self.blockQueue[id].add(block.Hash())
+		if queue := self.blockQueue[id]; queue != nil {
+			queue.add(block.Hash())
+		}
 	}
-	id = self.filterManager.InstallFilter(filter)
-	self.blockQueue[id] = &hashQueue{timeout: time.Now()}
 	return id
 }
 
@@ -1022,16 +1028,24 @@ func (m callmsg) Value() *big.Int               { return m.value }
 func (m callmsg) Data() []byte                  { return m.data }
 
 type logQueue struct {
+	mu sync.Mutex
+
 	logs    state.Logs
 	timeout time.Time
 	id      int
 }
 
 func (l *logQueue) add(logs ...*state.Log) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+
 	l.logs = append(l.logs, logs...)
 }
 
 func (l *logQueue) get() state.Logs {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+
 	l.timeout = time.Now()
 	tmp := l.logs
 	l.logs = nil
@@ -1039,16 +1053,24 @@ func (l *logQueue) get() state.Logs {
 }
 
 type hashQueue struct {
+	mu sync.Mutex
+
 	hashes  []common.Hash
 	timeout time.Time
 	id      int
 }
 
 func (l *hashQueue) add(hashes ...common.Hash) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+
 	l.hashes = append(l.hashes, hashes...)
 }
 
 func (l *hashQueue) get() []common.Hash {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+
 	l.timeout = time.Now()
 	tmp := l.hashes
 	l.hashes = nil