diff options
Diffstat (limited to 'module/lib/beaker/synchronization.py')
| -rw-r--r-- | module/lib/beaker/synchronization.py | 54 |
1 files changed, 27 insertions, 27 deletions
diff --git a/module/lib/beaker/synchronization.py b/module/lib/beaker/synchronization.py index 6616ca78b..761303707 100644 --- a/module/lib/beaker/synchronization.py +++ b/module/lib/beaker/synchronization.py @@ -36,7 +36,7 @@ __all__ = ["file_synchronizer", "mutex_synchronizer", "null_synchronizer", class NameLock(object): """a proxy for an RLock object that is stored in a name based registry. - + Multiple threads can get a reference to the same RLock based on the name alone, and synchronize operations related to that name. @@ -115,7 +115,7 @@ class SynchronizerImpl(object): else: return self._state.get() state = property(state) - + def release_read_lock(self): state = self.state @@ -123,19 +123,19 @@ class SynchronizerImpl(object): raise LockError("lock is in writing state") if not state.reading: raise LockError("lock is not in reading state") - + if state.reentrantcount == 1: self.do_release_read_lock() state.reading = False state.reentrantcount -= 1 - + def acquire_read_lock(self, wait = True): state = self.state if state.writing: raise LockError("lock is in writing state") - + if state.reentrantcount == 0: x = self.do_acquire_read_lock(wait) if (wait or x): @@ -145,7 +145,7 @@ class SynchronizerImpl(object): elif state.reading: state.reentrantcount += 1 return True - + def release_write_lock(self): state = self.state @@ -159,15 +159,15 @@ class SynchronizerImpl(object): state.writing = False state.reentrantcount -= 1 - + release = release_write_lock - + def acquire_write_lock(self, wait = True): state = self.state if state.reading: raise LockError("lock is in reading state") - + if state.reentrantcount == 0: x = self.do_acquire_write_lock(wait) if (wait or x): @@ -182,13 +182,13 @@ class SynchronizerImpl(object): def do_release_read_lock(self): raise NotImplementedError() - + def do_acquire_read_lock(self): raise NotImplementedError() - + def do_release_write_lock(self): raise NotImplementedError() - + def do_acquire_write_lock(self): raise NotImplementedError() @@ -198,18 +198,18 @@ class FileSynchronizer(SynchronizerImpl): Adapted for Python/multithreads from Apache::Session::Lock::File, http://search.cpan.org/src/CWEST/Apache-Session-1.81/Session/Lock/File.pm - + This module does not unlink temporary files, because it interferes with proper locking. This can cause problems on certain systems (Linux) whose file systems (ext2) do not perform well with lots of files in one directory. To prevent this you should use a script to clean out old files from your lock directory. - + """ def __init__(self, identifier, lock_dir): super(FileSynchronizer, self).__init__() self._filedescriptor = util.ThreadLocal() - + if lock_dir is None: lock_dir = tempfile.gettempdir() else: @@ -224,14 +224,14 @@ class FileSynchronizer(SynchronizerImpl): def _filedesc(self): return self._filedescriptor.get() _filedesc = property(_filedesc) - + def _open(self, mode): filedescriptor = self._filedesc if filedescriptor is None: filedescriptor = os.open(self.filename, mode) self._filedescriptor.put(filedescriptor) return filedescriptor - + def do_acquire_read_lock(self, wait): filedescriptor = self._open(os.O_CREAT | os.O_RDONLY) if not wait: @@ -259,13 +259,13 @@ class FileSynchronizer(SynchronizerImpl): else: fcntl.flock(filedescriptor, fcntl.LOCK_EX) return True - + def do_release_read_lock(self): self._release_all_locks() - + def do_release_write_lock(self): self._release_all_locks() - + def _release_all_locks(self): filedescriptor = self._filedesc if filedescriptor is not None: @@ -276,7 +276,7 @@ class FileSynchronizer(SynchronizerImpl): class ConditionSynchronizer(SynchronizerImpl): """a synchronizer using a Condition.""" - + def __init__(self, identifier): super(ConditionSynchronizer, self).__init__() @@ -308,12 +308,12 @@ class ConditionSynchronizer(SynchronizerImpl): if not wait: return True - + def do_release_read_lock(self): self.condition.acquire() try: self.async -= 1 - + # check if we are the last asynchronous reader thread # out the door. if self.async == 0: @@ -326,13 +326,13 @@ class ConditionSynchronizer(SynchronizerImpl): "release_read_locks called") finally: self.condition.release() - + def do_acquire_write_lock(self, wait = True): self.condition.acquire() try: # here, we are not a synchronous reader, and after returning, # assuming waiting or immediate availability, we will be. - + if wait: # if another sync is working, wait while self.current_sync_operation is not None: @@ -342,7 +342,7 @@ class ConditionSynchronizer(SynchronizerImpl): # we dont want to wait, so forget it if self.current_sync_operation is not None: return False - + # establish ourselves as the current sync # this indicates to other read/write operations # that they should wait until this is None again @@ -359,7 +359,7 @@ class ConditionSynchronizer(SynchronizerImpl): return False finally: self.condition.release() - + if not wait: return True |