1 files changed, 157 insertions, 0 deletions
diff --git a/src/python/persist.py b/src/python/persist.py
new file mode 100644
index 0000000..1357609
--- /dev/null
+++ b/src/python/persist.py
@@ -0,0 +1,157 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# libavg - Media Playback Engine.
+# Copyright (C) 2003-2014 Ulrich von Zadow
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later version.
+#
+# This library 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
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#
+# Current versions can be found at www.libavg.de
+#
+# Original author of this file is OXullo Interecans <x at brainrapers dot org>
+
+
+import os
+import time
+import cPickle as pickle
+
+import libavg
+
+
+class Persist(object):
+    def __init__(self, storeFile, initialData, validator=lambda v: True,
+            autoCommit=False):
+        self.__storeFile = storeFile
+        
+        if hasattr(initialData, '__call__'):
+            initialData = initialData()
+        elif initialData is None:
+            initialData = dict()
+
+        if os.path.exists(self.__storeFile):
+            if not os.path.isfile:
+                raise RuntimeError('%s dump file is not a plain file' % self)
+            elif not os.access(self.__storeFile, os.R_OK | os.W_OK):
+                raise RuntimeError('%s dump file'
+                        'cannot be accessed with r/w permissions' % self)
+
+        try:
+            f = open(self.__storeFile)
+        except IOError:
+            libavg.logger.debug('Initializing %s' % self)
+            self.data = initialData
+            self.commit()
+        else:
+            try:
+                self.data = pickle.load(f)
+            except:
+                f.close()
+                libavg.logger.warning('Persist %s is corrupted or unreadable, '
+                        'reinitializing' % self)
+                self.data = initialData
+                self.commit()
+            else:
+                f.close()
+                if not validator(self.data):
+                    libavg.logger.warning('Sanity check failed for %s, '
+                            'reinitializing' % self)
+                    self.data = initialData
+                    self.commit()
+                else:
+                    libavg.logger.debug('%s successfully loaded' % self)
+
+        if autoCommit:
+            import atexit
+            atexit.register(self.commit)
+
+    def __repr__(self):
+        return '<%s %s>' % (self.__class__.__name__, self.__storeFile)
+
+    @property
+    def storeFile(self):
+        return self.__storeFile
+
+    def commit(self):
+        tempFile = self.__storeFile + '.tmp.' + str(int(time.time() * 1000))
+
+        try:
+            with open(tempFile, 'wb') as f:
+                pickle.dump(self.data, f)
+        except Exception, e:
+            libavg.logger.warning('Cannot save %s (%s)' % (self.__storeFile, str(e)))
+            return False
+        else:
+            if os.path.exists(self.__storeFile):
+                try:
+                    os.remove(self.__storeFile)
+                except Exception, e:
+                    libavg.logger.warning('Cannot overwrite dump file '
+                            '%s (%s)' % (self, str(e)))
+                    return False
+            try:
+                os.rename(tempFile, self.__storeFile)
+            except Exception, e:
+                libavg.logger.warning('Cannot save %s (%s)' % (self, str(e)))
+                os.remove(tempFile)
+                return False
+            else:
+                libavg.logger.debug('%s saved' % self)
+                return True
+
+
+class UserPersistentData(Persist):
+    def __init__(self, appName, fileName, *args, **kargs):
+        basePath = os.path.join(self._getUserDataPath(), appName)
+        fullPath = os.path.join(basePath, '%s.pkl' % fileName)
+
+        try:
+            os.makedirs(basePath)
+        except OSError, e:
+            import errno
+            if e.errno != errno.EEXIST:
+                raise
+
+        super(UserPersistentData, self).__init__(fullPath, *args, **kargs)
+
+    def _getUserDataPath(self):
+        if os.name == 'posix':
+            path = os.path.join(os.environ['HOME'], '.avg')
+        elif os.name == 'nt':
+            path = os.path.join(os.environ['APPDATA'], 'Avg')
+        else:
+            raise RuntimeError('Unsupported system %s' % os.name)
+
+        return path
+
+
+if __name__ == '__main__':
+    testFile = './testfile.pkl'
+    initialData = {'initial': True}
+    p = Persist(testFile, initialData)
+    p.commit()
+    p.data['initial'] = False
+    p.commit()
+
+    p = Persist(testFile, initialData)
+    print not p.data['initial']
+
+    os.unlink(testFile)
+
+    p = UserPersistentData('myapp', 'hiscore', initialData)
+    p.data['initial'] = False
+    p.commit()
+
+    print p
+