Close file watcher when target is deleted.

runtime/bin/file_patch.dart

Index: runtime/bin/file_patch.dart
diff --git a/runtime/bin/file_patch.dart b/runtime/bin/file_patch.dart
index 93367f4d9d7098d50c39064ebed40251adf011a1..a08eaf99b64acc270937220047dbb834678f1fee 100644
--- a/runtime/bin/file_patch.dart
+++ b/runtime/bin/file_patch.dart
@@ -76,6 +76,7 @@ class _FileSystemWatcherImpl
     }
     var socket = new _RawSocket(new _NativeSocket.watch(socketId));
     _subscription = socket.expand((event) {
+      bool stop = false;
       var events = [];
       var pair = {};
       if (event == RawSocketEvent.READ) {
@@ -87,18 +88,22 @@ class _FileSystemWatcherImpl
           }
           return path;
         }
+        void add(event) {
+          if ((event.type & _events) == 0) return;
+          events.add(event);
+        }
         while (socket.available() > 0) {
           for (var event in _readEvents()) {
             if (event == null) continue;
             var path = getPath(event);
             if ((event[0] & FileSystemEvent.CREATE) != 0) {
-              events.add(new FileSystemCreateEvent._(path));
+              add(new FileSystemCreateEvent._(path));
             }
             if ((event[0] & FileSystemEvent.MODIFY) != 0) {
-              events.add(new FileSystemModifyEvent._(path, true));
+              add(new FileSystemModifyEvent._(path, true));
             }
             if ((event[0] & FileSystemEvent._MODIFY_ATTRIBUTES) != 0) {
-              events.add(new FileSystemModifyEvent._(path, false));
+              add(new FileSystemModifyEvent._(path, false));
             }
             if ((event[0] & FileSystemEvent.MOVE) != 0) {
               int link = event[1];
@@ -111,11 +116,15 @@ class _FileSystemWatcherImpl
                   pair[link] = event;
                 }
               } else {
-                events.add(new FileSystemMoveEvent._(path, null));
+                add(new FileSystemMoveEvent._(path, null));
               }
             }
             if ((event[0] & FileSystemEvent.DELETE) != 0) {
-              events.add(new FileSystemDeleteEvent._(path));
+              add(new FileSystemDeleteEvent._(path));
+            }
+            if ((event[0] & FileSystemEvent._DELETE_SELF) != 0) {
+              add(new FileSystemDeleteEvent._(path));
+              stop = true;
             }
           }
         }
@@ -127,9 +136,9 @@ class _FileSystemWatcherImpl
       } else {
         assert(false);
       }
+      if (stop) socket.close();
       return events;
     })
-    .where((event) => (event.type & _events) != 0)
     .listen(_controller.add, onDone: _cancel);
   }
 
@@ -138,6 +147,7 @@ class _FileSystemWatcherImpl
     if (_subscription != null) {
       _subscription.cancel();
     }
+    _controller.close();
   }
 
   Stream<FileSystemEvent> get stream => _controller.stream;