Dokan: improve thread-safety of timeout-protection mechanism

fs/expose/dokan/__init__.py

@@ -67,7 +67,7 @@ import subprocess
 import cPickle
 import datetime
 import ctypes
-import Queue
+from collections import deque
 
 from fs.base import threading
 from fs.errors import *
@@ -197,7 +197,8 @@ def handle_fs_errors(func):
 
 _TIMEOUT_PROTECT_THREAD = None
 _TIMEOUT_PROTECT_LOCK = threading.Lock()
-_TIMEOUT_PROTECT_QUEUE = Queue.Queue()
+_TIMEOUT_PROTECT_COND = threading.Condition(_TIMEOUT_PROTECT_LOCK)
+_TIMEOUT_PROTECT_QUEUE = deque()
 _TIMEOUT_PROTECT_WAIT_TIME = 4 * 60
 _TIMEOUT_PROTECT_RESET_TIME = 5 * 60 * 1000
 
@@ -211,20 +212,30 @@ def _start_timeout_protect_thread():
     global _TIMEOUT_PROTECT_THREAD
     with _TIMEOUT_PROTECT_LOCK:
         if _TIMEOUT_PROTECT_THREAD is None:
-            def target():
-                while True:
-                    (when,info,finished) = _TIMEOUT_PROTECT_QUEUE.get()
-                    if finished:
-                        continue
-                    now = time.time()
-                    wait_time = max(0,_TIMEOUT_PROTECT_WAIT_TIME - now + when)
-                    time.sleep(wait_time)
-                    libdokan.DokanResetTimeout(_TIMEOUT_PROTECT_RESET_TIME,info)
-                    _TIMEOUT_PROTECT_QUEUE.put((now+wait_time,info,finished))
+            target = _run_timeout_protect_thread
             _TIMEOUT_PROTECT_THREAD = threading.Thread(target=target)
             _TIMEOUT_PROTECT_THREAD.daemon = True
             _TIMEOUT_PROTECT_THREAD.start()
 
+def _run_timeout_protect_thread():
+    while True:
+        with _TIMEOUT_PROTECT_COND:
+            try:
+                (when,info,finished) = _TIMEOUT_PROTECT_QUEUE.popleft()
+            except IndexError:
+                _TIMEOUT_PROTECT_COND.wait()
+                continue
+        if finished:
+            continue
+        now = time.time()
+        wait_time = max(0,_TIMEOUT_PROTECT_WAIT_TIME - now + when)
+        time.sleep(wait_time)
+        with _TIMEOUT_PROTECT_LOCK:
+            if finished:
+                continue
+            libdokan.DokanResetTimeout(_TIMEOUT_PROTECT_RESET_TIME,info)
+            _TIMEOUT_PROTECT_QUEUE.append((now+wait_time,info,finished))
+
 
 def timeout_protect(func):
     """Method decorator to enable timeout protection during call.
@@ -239,10 +250,13 @@ def timeout_protect(func):
         info = args[-1]
         finished = []
         try:
-            _TIMEOUT_PROTECT_QUEUE.put((time.time(),info,finished))
+            with _TIMEOUT_PROTECT_COND:
+                _TIMEOUT_PROTECT_QUEUE.append((time.time(),info,finished))
+                _TIMEOUT_PROTECT_COND.notify()
             return func(self,*args)
         finally:
-            finished.append(True)
+            with _TIMEOUT_PROTECT_LOCK:
+                finished.append(True)
     return wrapper