fix issue #377 and a bug in queue

eth/downloader/downloader_test.go

@@ -1347,7 +1347,7 @@ func testBlockHeaderAttackerDropping(t *testing.T, protocol int) {
 	defer tester.terminate()
 
 	for i, tt := range tests {
-		// Register a new peer and ensure it's presence
+		// Register a new peer and ensure its presence
 		id := fmt.Sprintf("test %d", i)
 		if err := tester.newPeer(id, protocol, []common.Hash{tester.genesis.Hash()}, nil, nil, nil); err != nil {
 			t.Fatalf("test %d: failed to register new peer: %v", i, err)

eth/downloader/queue.go

@@ -235,8 +235,7 @@ func (q *queue) ShouldThrottleReceipts() bool {
 }
 
 // resultSlots calculates the number of results slots available for requests
-// whilst adhering to both the item and the memory limit too of the results
-// cache.
+// whilst adhering to both the item and the memory limits of the result cache.
 func (q *queue) resultSlots(pendPool map[string]*fetchRequest, donePool map[common.Hash]struct{}) int {
 	// Calculate the maximum length capped by the memory limit
 	limit := len(q.resultCache)
@@ -349,7 +348,7 @@ func (q *queue) Schedule(headers []*types.Header, from uint64) []*types.Header {
 }
 
 // Results retrieves and permanently removes a batch of fetch results from
-// the cache. the result slice will be empty if the queue has been closed.
+// the cache. The result slice will be empty if the queue has been closed.
 func (q *queue) Results(block bool) []*fetchResult {
 	q.lock.Lock()
 	defer q.lock.Unlock()
@@ -511,7 +510,6 @@ func (q *queue) reserveHeaders(p *peerConnection, count int, taskPool map[common
 		index := int(header.Number.Int64() - int64(q.resultOffset))
 		if index >= len(q.resultCache) || index < 0 {
 			log.Error("index allocation went beyond available resultCache space", "index", index, "len.resultCache", len(q.resultCache), "blockNum", header.Number.Int64(), "resultOffset", q.resultOffset)
-			common.Report("index allocation went beyond available resultCache space")
 			return nil, false, errInvalidChain
 		}
 		if q.resultCache[index] == nil {
@@ -566,26 +564,29 @@ func (q *queue) reserveHeaders(p *peerConnection, count int, taskPool map[common
 
 // CancelHeaders aborts a fetch request, returning all pending skeleton indexes to the queue.
 func (q *queue) CancelHeaders(request *fetchRequest) {
+	q.lock.Lock()
+	defer q.lock.Unlock()
 	q.cancel(request, q.headerTaskQueue, q.headerPendPool)
 }
 
 // CancelBodies aborts a body fetch request, returning all pending headers to the
 // task queue.
 func (q *queue) CancelBodies(request *fetchRequest) {
+	q.lock.Lock()
+	defer q.lock.Unlock()
 	q.cancel(request, q.blockTaskQueue, q.blockPendPool)
 }
 
 // CancelReceipts aborts a body fetch request, returning all pending headers to
 // the task queue.
 func (q *queue) CancelReceipts(request *fetchRequest) {
+	q.lock.Lock()
+	defer q.lock.Unlock()
 	q.cancel(request, q.receiptTaskQueue, q.receiptPendPool)
 }
 
 // Cancel aborts a fetch request, returning all pending hashes to the task queue.
 func (q *queue) cancel(request *fetchRequest, taskQueue *prque.Prque, pendPool map[string]*fetchRequest) {
-	q.lock.Lock()
-	defer q.lock.Unlock()
-
 	if request.From > 0 {
 		taskQueue.Push(request.From, -int64(request.From))
 	}