osfs/watch_win32: enqueue all IO operations from the same thread

fs/osfs/watch_win32.py

@@ -15,6 +15,7 @@ import stat
 import struct
 import ctypes
 import ctypes.wintypes
+import traceback
 
 from fs.errors import *
 from fs.path import *
@@ -194,6 +195,7 @@ class WatchedDirectory(object):
                           None)
         self.result = ctypes.create_string_buffer(1024)
         self.overlapped = overlapped = OVERLAPPED()
+        self.ready = threading.Event()
 
     def __del__(self):
         self.close()
@@ -243,12 +245,15 @@ class WatchThread(threading.Thread):
         super(WatchThread,self).__init__()
         self.closed = False
         self.watched_directories = {}
-        self._iocp = CreateIoCompletionPort(INVALID_HANDLE_VALUE,None,0,1)
+        self.ready = threading.Event()
+        self._iocp = None
+        self._new_watches = Queue.Queue()
 
     def close(self):
         if not self.closed:
             self.closed = True
-            PostQueuedCompletionStatus(self._iocp,0,1,None)
+            if self._iocp:
+                PostQueuedCompletionStatus(self._iocp,0,1,None)
 
     def add_watcher(self,callback,path,events,recursive):
         if os.path.isfile(path):
@@ -330,28 +335,46 @@ class WatchThread(threading.Thread):
 
     def run(self):
         try:
+            self._iocp = CreateIoCompletionPort(INVALID_HANDLE_VALUE,None,0,1)
+            self.ready.set()
             nbytes = ctypes.wintypes.DWORD()
             iocpkey = ctypes.wintypes.DWORD()
             overlapped = OVERLAPPED()
             while not self.closed:
-                GetQueuedCompletionStatus(self._iocp,
-                                          ctypes.byref(nbytes),
-                                          ctypes.byref(iocpkey),
-                                          ctypes.byref(overlapped),
-                                          -1)
-                if iocpkey.value > 1:
-                    w = self.watched_directories[iocpkey.value]
-                    w.complete(nbytes.value)
-                    w.post()
+                try:
+                    GetQueuedCompletionStatus(self._iocp,
+                                              ctypes.byref(nbytes),
+                                              ctypes.byref(iocpkey),
+                                              ctypes.byref(overlapped),
+                                              -1)
+                except WindowsError:
+                    traceback.print_exc()
+                else:
+                    if iocpkey.value > 1:
+                        w = self.watched_directories[iocpkey.value]
+                        w.complete(nbytes.value)
+                        w.post()
+                    elif not self.closed:
+                        try:
+                            while True:
+                                w = self._new_watches.get_nowait()
+                                CreateIoCompletionPort(w.handle,self._iocp,hash(w),0)
+                                w.post()
+                                w.ready.set()
+                        except Queue.Empty:
+                            pass
         finally:
+            self.ready.set()
             for w in self.watched_directories.itervalues():
                 w.close()
-            CloseHandle(self._iocp)
+            if self._iocp:
+                CloseHandle(self._iocp)
 
     def attach_watched_directory(self,w):
         self.watched_directories[hash(w)] = w
-        CreateIoCompletionPort(w.handle,self._iocp,hash(w),0)
-        w.post()
+        self._new_watches.put(w)
+        PostQueuedCompletionStatus(self._iocp,0,1,None)
+        w.ready.wait()
 
 
 class OSFSWatchMixin(WatchableFSMixin):
@@ -402,6 +425,7 @@ class OSFSWatchMixin(WatchableFSMixin):
                 if self.__watch_thread is None:
                     wt = WatchThread()
                     wt.start()
+                    wt.ready.wait()
                     OSFSWatchMixin.__watch_thread = wt
             finally:
                 self.__watch_lock.release()
@@ -415,7 +439,10 @@ class OSFSWatchMixin(WatchableFSMixin):
                 return
             if not force and OSFSWatchMixin.__watch_thread.watched_directories:
                 return
-            OSFSWatchMixin.__watch_thread.close()
+            try:
+                OSFSWatchMixin.__watch_thread.close()
+            except EnvironmentError:
+                pass
             OSFSWatchMixin.__watch_thread = None
         finally:
             self.__watch_lock.release()