python
diff --git a/‎Lib/queue.py
Copy file name to clipboardExpand all lines: Lib/queue.py
+29-23Lines changed: 29 additions & 23 deletions b/‎Lib/queue.py
Copy file name to clipboardExpand all lines: Lib/queue.py
+29-23Lines changed: 29 additions & 23 deletions
@@ -30,11 +30,9 @@ class ShutDown(Exception):
     '''Raised when put/get with shut-down queue.'''
 
 
-class _QueueState(enum.Enum):
-    ALIVE = "alive"
-    SHUTDOWN = "shutdown"
-    SHUTDOWN_IMMEDIATE = "shutdown-immediate"
-
+_queue_alive = "alive"
+_queue_shutdown = "shutdown"
+_queue_shutdown_immediate = "shutdown-immediate"
 
 class Queue:
     '''Create a queue object with a given maximum size.
@@ -66,7 +64,7 @@ def __init__(self, maxsize=0):
         self.unfinished_tasks = 0
 
         # Queue shut-down state
-        self.shutdown_state = _QueueState.ALIVE
+        self.shutdown_state = _queue_alive
 
     def task_done(self):
         '''Indicate that a formerly enqueued task is complete.
@@ -83,6 +81,9 @@ def task_done(self):
         placed in the queue.
         '''
         with self.all_tasks_done:
+            # here `self.all_task_done` uses `self.mutex`
+            if self.shutdown_state == _queue_shutdown_immediate:
+                raise ShutDown
             unfinished = self.unfinished_tasks - 1
             if unfinished <= 0:
                 if unfinished < 0:
@@ -100,10 +101,13 @@ def join(self):
         When the count of unfinished tasks drops to zero, join() unblocks.
         '''
         with self.all_tasks_done:
+            # here `self.all_task_done` uses `self.mutex`
+            if self.shutdown_state == _queue_shutdown_immediate:
+                raise ShutDown
             while self.unfinished_tasks:
-                if self.shutdown_state is _QueueState.SHUTDOWN_IMMEDIATE:
-                    return
                 self.all_tasks_done.wait()
+                if self.shutdown_state == _queue_shutdown_immediate:
+                    raise ShutDown
 
     def qsize(self):
         '''Return the approximate size of the queue (not reliable!).'''
@@ -146,17 +150,18 @@ def put(self, item, block=True, timeout=None):
         is immediately available, else raise the Full exception ('timeout'
         is ignored in that case).
         '''
-        if self.shutdown_state is not _QueueState.ALIVE:
-            raise ShutDown
         with self.not_full:
+            # here `self.not_full` uses `self.mutex``
+            if self.shutdown_state != _queue_alive:
+                raise ShutDown
             if self.maxsize > 0:
                 if not block:
                     if self._qsize() >= self.maxsize:
                         raise Full
                 elif timeout is None:
                     while self._qsize() >= self.maxsize:
                         self.not_full.wait()
-                        if self.shutdown_state is not _QueueState.ALIVE:
+                        if self.shutdown_state != _queue_alive:
                             raise ShutDown
                 elif timeout < 0:
                     raise ValueError("'timeout' must be a non-negative number")
@@ -167,7 +172,7 @@ def put(self, item, block=True, timeout=None):
                         if remaining <= 0.0:
                             raise Full
                         self.not_full.wait(remaining)
-                        if self.shutdown_state is not _QueueState.ALIVE:
+                        if self.shutdown_state != _queue_alive:
                             raise ShutDown
             self._put(item)
             self.unfinished_tasks += 1
@@ -184,35 +189,36 @@ def get(self, block=True, timeout=None):
         available, else raise the Empty exception ('timeout' is ignored
         in that case).
         '''
-        if self.shutdown_state is _QueueState.SHUTDOWN_IMMEDIATE:
-            raise ShutDown
         with self.not_empty:
+            # here `self.not_empty` uses `self.mutex`
+            if self.shutdown_state == _queue_shutdown_immediate:
+                raise ShutDown
             if not block:
                 if not self._qsize():
-                    if self.shutdown_state is not _QueueState.ALIVE:
+                    if self.shutdown_state != _queue_alive:
                         raise ShutDown
                     raise Empty
             elif timeout is None:
                 while not self._qsize():
-                    if self.shutdown_state is not _QueueState.ALIVE:
+                    if self.shutdown_state != _queue_alive:
                         raise ShutDown
                     self.not_empty.wait()
-                    if self.shutdown_state is not _QueueState.ALIVE:
+                    if self.shutdown_state != _queue_alive:
                         raise ShutDown
             elif timeout < 0:
                 raise ValueError("'timeout' must be a non-negative number")
             else:
                 endtime = time() + timeout
                 while not self._qsize():
-                    if self.shutdown_state is not _QueueState.ALIVE:
+                    if self.shutdown_state != _queue_alive:
                         raise ShutDown
                     remaining = endtime - time()
                     if remaining <= 0.0:
                         raise Empty
                     self.not_empty.wait(remaining)
-                    if self.shutdown_state is not _QueueState.ALIVE:
+                    if self.shutdown_state != _queue_alive:
                         raise ShutDown
-            if self.shutdown_state is _QueueState.SHUTDOWN_IMMEDIATE:
+            if self.shutdown_state == _queue_shutdown_immediate:
                 raise ShutDown
             item = self._get()
             self.not_full.notify()
@@ -244,19 +250,19 @@ def shutdown(self, immediate=False):
         and join() if 'immediate'. The ShutDown exception is raised.
         '''
         with self.mutex:
-            if self.shutdown_state is _QueueState.SHUTDOWN_IMMEDIATE:
+            if self.shutdown_state is _queue_shutdown_immediate:
                 return
 
             if immediate:
-                self.shutdown_state = _QueueState.SHUTDOWN_IMMEDIATE
+                self.shutdown_state = _queue_shutdown_immediate
                 self.not_empty.notify_all()
                 # set self.unfinished_tasks to 0
                 # to break the loop in 'self.join()'
                 # when quits from `wait()`
                 self.unfinished_tasks = 0
                 self.all_tasks_done.notify_all()
             else:
-                self.shutdown_state = _QueueState.SHUTDOWN
+                self.shutdown_state = _queue_shutdown
             self.not_full.notify_all()
 
     # Override these methods to implement other queue organizations