lock around map access

changes/watch_darwin.go

@@ -21,6 +21,7 @@ import "C"
 
 import (
 	"math/rand"
+	"sync"
 	"time"
 	"unsafe"
 )
@@ -30,14 +31,18 @@ var (
 	chans    = make(map[string](chan string))
 	interval = 700 * time.Millisecond
 	now      = C.FSEventStreamEventId((1 << 64) - 1)
+
+	lock sync.Mutex
 )
 
 func init() {
 	rand.Seed(time.Now().UTC().UnixNano())
 }
 
 func startScanner(dir string) {
+	lock.Lock()
 	chans[dir] = make(chan string)
+	lock.Unlock()
 
 	cpaths := C.fswatch_make_mutable_array()
 	defer C.free(unsafe.Pointer(cpaths))
@@ -65,8 +70,16 @@ func waitForNextScan(dir string) {
 	fired := false
 
 	for {
+		lock.Lock()
+		ch, ok := chans[dir]
+		lock.Unlock()
+
+		if !ok {
+			return
+		}
+
 		select {
-		case <-chans[dir]:
+		case <-ch:
 			fired = true
 		case <-tick:
 			if fired {
@@ -80,7 +93,11 @@ func waitForNextScan(dir string) {
 func callback(stream C.FSEventStreamRef, info unsafe.Pointer, count C.size_t, paths **C.char, flags *C.FSEventStreamEventFlags, ids *C.FSEventStreamEventId) {
 	dir := C.GoString((*C.char)(info))
 
-	if ch, ok := chans[dir]; ok {
+	lock.Lock()
+	ch, ok := chans[dir]
+	lock.Unlock()
+
+	if ok {
 		ch <- ""
 	}
 }

sync/sync.go

@@ -183,9 +183,9 @@ func (s *Sync) syncIncomingAdds(adds []changes.Change, st Stream) {
 
 				local := filepath.Join(s.Local, rel)
 
+				s.lock.Lock()
 				s.outgoingBlocks[rel] += 1
-
-				os.MkdirAll(filepath.Dir(local), 0755)
+				s.lock.Unlock()
 
 				tmpfile, err := ioutil.TempFile("", filepath.Base(rel))
 				if err != nil {
@@ -211,6 +211,12 @@ func (s *Sync) syncIncomingAdds(adds []changes.Change, st Stream) {
 					return
 				}
 
+				err = os.MkdirAll(filepath.Dir(local), 0755)
+				if err != nil {
+					st <- fmt.Sprintf("error: %s", err)
+					return
+				}
+
 				err = os.Rename(tmpfile.Name(), local)
 				if err != nil {
 					st <- fmt.Sprintf("error: %s", err)
@@ -264,7 +270,9 @@ func (s *Sync) syncOutgoingAdds(adds []changes.Change, st Stream) {
 
 		remote := filepath.Join(s.Remote, a.Path)
 
+		s.lock.Lock()
 		s.incomingBlocks[a.Path] += 1
+		s.lock.Unlock()
 
 		tgz.WriteHeader(&tar.Header{
 			Name:    remote,