Close file watcher when target is deleted.

BUG=http://code.google.com/p/dart/issues/detail?id=14374
R=sgjesse@google.com

Review URL: https://codereview.chromium.org//39613002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@29159 260f80e4-7a28-3924-810f-c04153c831b5

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;

runtime/bin/file_system_watcher.h

@@ -24,7 +24,8 @@ class FileSystemWatcher {
     kModifyContent = 1 << 1,
     kDelete = 1 << 2,
     kMove = 1 << 3,
-    kModefyAttribute = 1 << 4
+    kModefyAttribute = 1 << 4,
+    kDeleteSelf = 1 << 5
   };
 
   struct Event {

runtime/bin/file_system_watcher_linux.cc

@@ -24,7 +24,7 @@ intptr_t FileSystemWatcher::WatchPath(const char* path,
                                       bool recursive) {
   int fd = TEMP_FAILURE_RETRY(inotify_init1(IN_NONBLOCK | IN_CLOEXEC));
   if (fd < 0) return -1;
-  int list_events = 0;
+  int list_events = IN_DELETE_SELF;
   if (events & kCreate) list_events |= IN_CREATE;
   if (events & kModifyContent) list_events |= IN_MODIFY | IN_ATTRIB;
   if (events & kDelete) list_events |= IN_DELETE;
@@ -56,7 +56,7 @@ Dart_Handle FileSystemWatcher::ReadEvents(intptr_t id) {
   if (bytes < 0) {
     return DartUtils::NewDartOSError();
   }
-  const intptr_t kMaxCount = kBufferSize / kEventSize + 1;
+  const intptr_t kMaxCount = bytes / kEventSize;
   Dart_Handle events = Dart_NewList(kMaxCount);
   intptr_t offset = 0;
   intptr_t i = 0;
@@ -70,6 +70,7 @@ Dart_Handle FileSystemWatcher::ReadEvents(intptr_t id) {
     if (e->mask & IN_CREATE) mask |= kCreate;
     if (e->mask & IN_MOVE) mask |= kMove;
     if (e->mask & IN_DELETE) mask |= kDelete;
+    if (e->mask & IN_DELETE_SELF) mask |= kDeleteSelf;
     Dart_ListSetAt(event, 0, Dart_NewInteger(mask));
     Dart_ListSetAt(event, 1, Dart_NewInteger(e->cookie));
     if (e->len > 0) {

sdk/lib/io/file_system_entity.dart

@@ -353,8 +353,13 @@ abstract class FileSystemEntity {
    *     files and directories. Recursive watching is supported.
    *
    * The system will start listening for events once the returned [Stream] is
-   * being listened to, not when the call to [watch] is issued. Note that the
+   * being listened to, not when the call to [watch] is issued.
-   * returned [Stream] is endless. To stop the [Stream], cancel the subscription.
+   *
+   * Note that the returned [Stream] is endless, unless:
+   *
+   *   * The [Stream] is canceled, e.g. by calling `cancel` on the
+   *      [StreamSubscription].
+   *   * The [FileSystemEntity] being watches, is deleted.
    */
   Stream<FileSystemEvent> watch({int events: FileSystemEvent.ALL,
                                  bool recursive: false})
@@ -623,6 +628,7 @@ class FileSystemEvent {
   static const int ALL = CREATE | MODIFY | DELETE | MOVE;
 
   static const int _MODIFY_ATTRIBUTES = 1 << 4;
+  static const int _DELETE_SELF = 1 << 5;
 
   /**
    * The type of event. See [FileSystemEvent] for a list of events.

tests/standalone/io/file_system_watcher_test.dart

@@ -111,6 +111,24 @@ void testWatchDeleteFile() {
 }
 
 
+void testWatchDeleteDir() {
+  var dir = Directory.systemTemp.createTempSync('dart_file_system_watcher');
+  var watcher = dir.watch(events: 0);
+
+  asyncStart();
+  var sub;
+  sub = watcher.listen((event) {
+    if (event is FileSystemDeleteEvent) {
+      Expect.isTrue(event.path == dir.path);
+    }
+  }, onDone: () {
+    asyncEnd();
+  });
+
+  dir.deleteSync();
+}
+
+
 void testWatchOnlyModifyFile() {
   var dir = Directory.systemTemp.createTempSync('dart_file_system_watcher');
   var file = new File(dir.path + '/file');
@@ -244,6 +262,7 @@ void main() {
   testWatchModifyFile();
   testWatchMoveFile();
   testWatchDeleteFile();
+  testWatchDeleteDir();
   testWatchOnlyModifyFile();
   testMultipleEvents();
   testWatchNonRecursive();