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Author: zmedico |
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Date: 2008-07-31 10:37:43 +0000 (Thu, 31 Jul 2008) |
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New Revision: 11297 |
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|
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Modified: |
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main/trunk/pym/_emerge/__init__.py |
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Log: |
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Bug #233458 - Fix AsynchronousTask exit listener handling so that an exit |
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listener will never get called after it's been passed into |
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removeExitListener(), since the caller of removeExitListener() needs to |
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be able to be able to trust that the given exit listener will not be |
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called under any circumstances. |
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|
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|
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Modified: main/trunk/pym/_emerge/__init__.py |
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=================================================================== |
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--- main/trunk/pym/_emerge/__init__.py 2008-07-31 07:25:35 UTC (rev 11296) |
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+++ main/trunk/pym/_emerge/__init__.py 2008-07-31 10:37:43 UTC (rev 11297) |
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@@ -1599,7 +1599,7 @@ |
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""" |
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|
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__slots__ = ("background", "cancelled", "returncode") + \ |
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- ("_exit_listeners", "_start_listeners") |
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+ ("_exit_listeners", "_exit_listener_stack", "_start_listeners") |
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|
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def start(self): |
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""" |
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@@ -1665,6 +1665,8 @@ |
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|
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def removeExitListener(self, f): |
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if self._exit_listeners is None: |
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+ if self._exit_listener_stack is not None: |
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+ self._exit_listener_stack.remove(f) |
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return |
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self._exit_listeners.remove(f) |
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|
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@@ -1680,12 +1682,22 @@ |
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|
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# This prevents recursion, in case one of the |
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# exit handlers triggers this method again by |
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- # calling wait(). |
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- exit_listeners = self._exit_listeners |
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+ # calling wait(). Use a stack that gives |
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+ # removeExitListener() an opportunity to consume |
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+ # listeners from the stack, before they can get |
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+ # called below. This is necessary because a call |
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+ # to one exit listener may result in a call to |
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+ # removeExitListener() for another listener on |
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+ # the stack. That listener needs to be removed |
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+ # from the stack since it would be inconsistent |
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+ # to call it after it has been been passed into |
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+ # removeExitListener(). |
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+ self._exit_listener_stack = self._exit_listeners |
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self._exit_listeners = None |
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|
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- for f in exit_listeners: |
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- f(self) |
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+ self._exit_listener_stack.reverse() |
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+ while self._exit_listener_stack: |
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+ self._exit_listener_stack.pop()(self) |
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|
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class PipeReader(AsynchronousTask): |
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