AsynchronousTask: add _cancel template method

7 files changed, 21 insertions, 17 deletions

diff --git a/pym/_emerge/AsynchronousLock.py b/pym/_emerge/AsynchronousLock.py
index c47a20788..6e0a1ac2a 100644
--- a/pym/_emerge/AsynchronousLock.py
+++ b/pym/_emerge/AsynchronousLock.py
@@ -198,6 +198,10 @@ class _LockProcess(AbstractPollTask):
 			raise AssertionError('lock process failed with returncode %s' \
 				% (proc.returncode,))
 
+	def _cancel(self):
+		if self._proc is not None:
+			self._proc.cancel()
+
 	def _wait(self):
 		if self.returncode is not None:
 			return self.returncode
diff --git a/pym/_emerge/AsynchronousTask.py b/pym/_emerge/AsynchronousTask.py
index 1918b839b..de0080042 100644
--- a/pym/_emerge/AsynchronousTask.py
+++ b/pym/_emerge/AsynchronousTask.py
@@ -1,4 +1,4 @@
-# Copyright 1999-2009 Gentoo Foundation
+# Copyright 1999-2011 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
 
 from _emerge.SlotObject import SlotObject
@@ -45,8 +45,17 @@ class AsynchronousTask(SlotObject):
 		return self.returncode
 
 	def cancel(self):
-		self.cancelled = True
-		self.wait()
+		if not self.cancelled:
+			self.cancelled = True
+			self._cancel()
+			self.wait()
+
+	def _cancel(self):
+		"""
+		Subclasses should implement this, as a template method
+		to be called by AsynchronousTask.cancel().
+		"""
+		pass
 
 	def addStartListener(self, f):
 		"""
diff --git a/pym/_emerge/CompositeTask.py b/pym/_emerge/CompositeTask.py
index 8e8f0843c..edc0768d7 100644
--- a/pym/_emerge/CompositeTask.py
+++ b/pym/_emerge/CompositeTask.py
@@ -13,15 +13,13 @@ class CompositeTask(AsynchronousTask):
 	def isAlive(self):
 		return self._current_task is not None
 
-	def cancel(self):
-		self.cancelled = True
+	def _cancel(self):
 		if self._current_task is not None:
 			if self._current_task is self._TASK_QUEUED:
 				self.returncode = 1
 				self._current_task = None
 			else:
 				self._current_task.cancel()
-		AsynchronousTask.cancel(self)
 
 	def _poll(self):
 		"""
diff --git a/pym/_emerge/FifoIpcDaemon.py b/pym/_emerge/FifoIpcDaemon.py
index c31508a83..a716dac7c 100644
--- a/pym/_emerge/FifoIpcDaemon.py
+++ b/pym/_emerge/FifoIpcDaemon.py
@@ -43,12 +43,10 @@ class FifoIpcDaemon(AbstractPollTask):
 	def isAlive(self):
 		return self._registered
 
-	def cancel(self):
+	def _cancel(self):
 		if self.returncode is None:
 			self.returncode = 1
-			self.cancelled = True
 		self._unregister()
-		AbstractPollTask.cancel(self)
 
 	def _wait(self):
 		if self.returncode is not None:
diff --git a/pym/_emerge/PipeReader.py b/pym/_emerge/PipeReader.py
index 061921a79..375c98f6a 100644
--- a/pym/_emerge/PipeReader.py
+++ b/pym/_emerge/PipeReader.py
@@ -32,11 +32,9 @@ class PipeReader(AbstractPollTask):
 	def isAlive(self):
 		return self._registered
 
-	def cancel(self):
+	def _cancel(self):
 		if self.returncode is None:
 			self.returncode = 1
-			self.cancelled = True
-		AbstractPollTask.cancel(self)
 
 	def _wait(self):
 		if self.returncode is not None:
diff --git a/pym/_emerge/SubProcess.py b/pym/_emerge/SubProcess.py
index 16c71fe3b..115af803d 100644
--- a/pym/_emerge/SubProcess.py
+++ b/pym/_emerge/SubProcess.py
@@ -41,15 +41,13 @@ class SubProcess(AbstractPollTask):
 		self.wait()
 		return self.returncode
 
-	def cancel(self):
+	def _cancel(self):
 		if self.isAlive():
 			try:
 				os.kill(self.pid, signal.SIGTERM)
 			except OSError as e:
 				if e.errno != errno.ESRCH:
 					raise
-				del e
-		AbstractPollTask.cancel(self)
 
 	def isAlive(self):
 		return self.pid is not None and \
diff --git a/pym/_emerge/TaskSequence.py b/pym/_emerge/TaskSequence.py
index 7a1bd5a47..1233c99d3 100644
--- a/pym/_emerge/TaskSequence.py
+++ b/pym/_emerge/TaskSequence.py
@@ -25,9 +25,8 @@ class TaskSequence(CompositeTask):
 	def _start(self):
 		self._start_next_task()
 
-	def cancel(self):
+	def _cancel(self):
 		self._task_queue.clear()
-		CompositeTask.cancel(self)
 
 	def _start_next_task(self):
 		self._start_task(self._task_queue.popleft(),