Cancel a running scan

lib/scanner/blockqueue.go

@@ -19,13 +19,13 @@ import (
 // workers are used in parallel. The outbox will become closed when the inbox
 // is closed and all items handled.
 
-func newParallelHasher(dir string, blockSize, workers int, outbox, inbox chan protocol.FileInfo, counter *int64, done chan struct{}) {
+func newParallelHasher(dir string, blockSize, workers int, outbox, inbox chan protocol.FileInfo, counter *int64, done, cancel chan struct{}) {
 	wg := sync.NewWaitGroup()
 	wg.Add(workers)
 
 	for i := 0; i < workers; i++ {
 		go func() {
-			hashFiles(dir, blockSize, outbox, inbox, counter)
+			hashFiles(dir, blockSize, outbox, inbox, counter, cancel)
 			wg.Done()
 		}()
 	}
@@ -59,19 +59,33 @@ func HashFile(path string, blockSize int, sizeHint int64, counter *int64) ([]pro
 	return Blocks(fd, blockSize, sizeHint, counter)
 }
 
-func hashFiles(dir string, blockSize int, outbox, inbox chan protocol.FileInfo, counter *int64) {
-	for f := range inbox {
-		if f.IsDirectory() || f.IsDeleted() {
-			panic("Bug. Asked to hash a directory or a deleted file.")
-		}
+func hashFiles(dir string, blockSize int, outbox, inbox chan protocol.FileInfo, counter *int64, cancel chan struct{}) {
+	for {
+		select {
+		case f, ok := <-inbox:
+			if !ok {
+				return
+			}
 
-		blocks, err := HashFile(filepath.Join(dir, f.Name), blockSize, f.CachedSize, counter)
-		if err != nil {
-			l.Debugln("hash error:", f.Name, err)
-			continue
-		}
+			if f.IsDirectory() || f.IsDeleted() {
+				panic("Bug. Asked to hash a directory or a deleted file.")
+			}
 
-		f.Blocks = blocks
-		outbox <- f
+			blocks, err := HashFile(filepath.Join(dir, f.Name), blockSize, f.CachedSize, counter)
+			if err != nil {
+				l.Debugln("hash error:", f.Name, err)
+				continue
+			}
+
+			f.Blocks = blocks
+			select {
+			case outbox <- f:
+			case <-cancel:
+				return
+			}
+
+		case <-cancel:
+			return
+		}
 	}
 }