own locking class, avoiding multiple acquire/releases

git-svn-id: https://linkchecker.svn.sourceforge.net/svnroot/linkchecker/trunk/linkchecker@2391 e7d03fd6-7b0d-0410-9947-9c21f3af8025

linkcheck/lock.py

@@ -0,0 +1,43 @@
+# -*- coding: iso-8859-1 -*-
+# Copyright (C) 2005  Bastian Kleineidam
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+"""
+Locking utility class.
+"""
+
+try:
+    import threading
+except ImportError:
+    import dummy_threading as threading
+
+lock_klass = threading.RLock().__class__
+
+class AssertLock (lock_klass):
+
+    def acquire (self, blocking=True):
+        """
+        Acquire lock.
+        """
+        assert not self._is_owned(), "deadlock"
+        super(AssertLock, self).acquire(blocking=blocking)
+
+    def release (self):
+        """
+        Release lock.
+        """
+        assert self._is_owned(), "double release"
+        super(AssertLock, self).release()
+