148 lines
4.8 KiB
Python
148 lines
4.8 KiB
Python
#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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#
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# Copyright 2011 Yesudeep Mangalapilly <yesudeep@gmail.com>
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# Copyright 2012 Google, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""
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:module: watchdog.observers.polling
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:synopsis: Polling emitter implementation.
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:author: yesudeep@google.com (Yesudeep Mangalapilly)
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Classes
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-------
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.. autoclass:: PollingObserver
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:members:
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:show-inheritance:
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.. autoclass:: PollingObserverVFS
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:members:
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:show-inheritance:
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:special-members:
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"""
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from __future__ import with_statement
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import os
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import threading
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from functools import partial
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from ..utils import stat as default_stat
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from ..utils.dirsnapshot import DirectorySnapshot, \
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DirectorySnapshotDiff
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from ..observers.api import (
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EventEmitter,
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BaseObserver,
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DEFAULT_OBSERVER_TIMEOUT,
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DEFAULT_EMITTER_TIMEOUT
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)
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from ..events import (
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DirMovedEvent,
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DirDeletedEvent,
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DirCreatedEvent,
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DirModifiedEvent,
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FileMovedEvent,
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FileDeletedEvent,
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FileCreatedEvent,
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FileModifiedEvent
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)
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class PollingEmitter(EventEmitter):
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"""
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Platform-independent emitter that polls a directory to detect file
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system changes.
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"""
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def __init__(self, event_queue, watch, timeout=DEFAULT_EMITTER_TIMEOUT,
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stat=default_stat, listdir=os.listdir):
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EventEmitter.__init__(self, event_queue, watch, timeout)
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self._snapshot = None
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self._lock = threading.Lock()
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self._take_snapshot = lambda: DirectorySnapshot(
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self.watch.path, self.watch.is_recursive, stat=stat, listdir=listdir)
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def on_thread_start(self):
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self._snapshot = self._take_snapshot()
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def queue_events(self, timeout):
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# We don't want to hit the disk continuously.
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# timeout behaves like an interval for polling emitters.
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if self.stopped_event.wait(timeout):
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return
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with self._lock:
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if not self.should_keep_running():
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return
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# Get event diff between fresh snapshot and previous snapshot.
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# Update snapshot.
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try:
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new_snapshot = self._take_snapshot()
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except OSError as e:
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self.queue_event(DirDeletedEvent(self.watch.path))
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self.stop()
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return
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except Exception as e:
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raise e
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events = DirectorySnapshotDiff(self._snapshot, new_snapshot)
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self._snapshot = new_snapshot
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# Files.
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for src_path in events.files_deleted:
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self.queue_event(FileDeletedEvent(src_path))
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for src_path in events.files_modified:
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self.queue_event(FileModifiedEvent(src_path))
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for src_path in events.files_created:
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self.queue_event(FileCreatedEvent(src_path))
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for src_path, dest_path in events.files_moved:
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self.queue_event(FileMovedEvent(src_path, dest_path))
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# Directories.
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for src_path in events.dirs_deleted:
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self.queue_event(DirDeletedEvent(src_path))
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for src_path in events.dirs_modified:
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self.queue_event(DirModifiedEvent(src_path))
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for src_path in events.dirs_created:
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self.queue_event(DirCreatedEvent(src_path))
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for src_path, dest_path in events.dirs_moved:
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self.queue_event(DirMovedEvent(src_path, dest_path))
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class PollingObserver(BaseObserver):
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"""
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Platform-independent observer that polls a directory to detect file
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system changes.
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"""
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def __init__(self, timeout=DEFAULT_OBSERVER_TIMEOUT):
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BaseObserver.__init__(self, emitter_class=PollingEmitter, timeout=timeout)
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class PollingObserverVFS(BaseObserver):
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"""
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File system independent observer that polls a directory to detect changes.
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"""
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def __init__(self, stat, listdir, polling_interval=1):
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"""
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:param stat: stat function. See ``os.stat`` for details.
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:param listdir: listdir function. See ``os.listdir`` for details.
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:type polling_interval: float
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:param polling_interval: interval in seconds between polling the file system.
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"""
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emitter_cls = partial(PollingEmitter, stat=stat, listdir=listdir)
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BaseObserver.__init__(self, emitter_class=emitter_cls, timeout=polling_interval)
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