Locking problems with DorothyLocker

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-- This time with patches attached....

I started using the pyds version from cvs and noticed locking problems if I
started pyds with the verbose option.

To track down the problems I changed Tool.py at two places:

* the tool threads are created with the tool name as thread name
* the lock object (DorothyRLock) are created with verbose=True

After these changes I noticed that DorothyRLock did not always lock
correctly - it seemed to not block if a lock was already acquired by
another thread. To correct this I changed the second locking attempt to
_RLock.acquire(self, blocking=1)

This change removed most of the locking problems, however sometimes I had
an error message about prevcontext not being initialized. So I also added
some code to always initialize prevcontext to None.

Garth, as you have written DorothyLocker, could you please review these
patches and submit them to Georg?

Regards,

Thomas


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Index: PyDS/DorothyLocker.py
===================================================================
RCS file: /pyds/PyDS/PyDS/DorothyLocker.py,v
retrieving revision 1.2
diff -u -r1.2 DorothyLocker.py
--- PyDS/DorothyLocker.py	14 Sep 2004 08:51:06 -0000	1.2
+++ PyDS/DorothyLocker.py	18 Sep 2004 12:08:14 -0000
@@ -102,6 +102,7 @@
 		myLocks = self.__threads.setdefault(me, [])
 		mycontext, myt = self.callContext(), time.time()
 
+		prevcontext = None
 		# If there were any locks... 
 		if myLocks: 
 			# Try to figure out whether the previous lock should have been 
@@ -136,7 +137,7 @@
 				# Whine whilst we wait for the lock to clear. 
 				whiner = LockWhiner(self, mycontext, myt, prevcontext, prevt)
 				whiner.start()
-				result = _RLock.acquire(self, blocking)
+				result = _RLock.acquire(self, blocking=1)
 				whiner.stop()
 		else: 
 			result = _RLock.acquire(self, blocking=0)
Index: PyDS/Tool.py
===================================================================
RCS file: /pyds/PyDS/PyDS/Tool.py,v
retrieving revision 1.195
diff -u -r1.195 Tool.py
--- PyDS/Tool.py	14 Sep 2004 08:57:38 -0000	1.195
+++ PyDS/Tool.py	18 Sep 2004 11:49:09 -0000
@@ -1143,7 +1143,7 @@
 		self.rss = 0
 		self.hasAPI = 1
 		if _PyDS.verbose:
-			self.lock = DorothyRLock() 
+			self.lock = DorothyRLock(verbose=True) 
 		else:
 			self.lock = threading.RLock()
 		self.lockedFrom = None
@@ -1334,6 +1334,7 @@
 		
 		background = threading.Thread(
 			target=thunk,
+			name=self.name,
 			args=[self, status],
 			kwargs={}
 		)

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