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# Dnotify -*- mode: python; coding: utf-8 -*-
# A simple FAM-like beast in Python
# Copyright © 2002 Colin Walters <walters@gnu.org>
# This file 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
import os, re, sys, string, stat, threading, Queue, time
import logging
from minidinstall import misc
class DnotifyException(Exception):
def __init__(self, value):
self._value = value
def __str__(self):
return `self._value`
class DirectoryNotifierFactory:
def create(self, dirs, use_dnotify=1, poll_time=30, logger=None, cancel_event=None):
if use_dnotify and os.access('/usr/bin/dnotify', os.X_OK):
if logger:
logger.debug("Using dnotify directory notifier")
return DnotifyDirectoryNotifier(dirs, logger)
else:
if logger:
logger.debug("Using mtime-polling directory notifier")
return MtimeDirectoryNotifier(dirs, poll_time, logger, cancel_event=cancel_event)
class DnotifyNullLoggingFilter(logging.Filter):
def filter(self, record):
return 0
class DirectoryNotifier:
def __init__(self, dirs, logger, cancel_event=None):
self._cwd = os.getcwd()
self._dirs = dirs
if cancel_event is None:
self._cancel_event = threading.Event()
else:
self._cancel_event = cancel_event
if logger is None:
self._logger = logging.getLogger("Dnotify")
self._logger.addFilter(DnotifyNullLoggingFilter())
else:
self._logger = logger
def cancelled(self):
return self._cancel_event.isSet()
class DirectoryNotifierAsyncWrapper(threading.Thread):
def __init__(self, dnotify, queue, logger=None, name=None):
if not name is None:
threading.Thread.__init__(self, name=name)
else:
threading.Thread.__init__(self)
self._eventqueue = queue
self._dnotify = dnotify
if logger is None:
self._logger = logging.getLogger("Dnotify")
self._logger.addFilter(DnotifyNullLoggingFilter())
else:
self._logger = logger
def cancel(self):
self._cancel_event.set()
def run(self):
self._logger.info('Created new thread (%s) for async directory notification' % (self.getName()))
while not self._dnotify.cancelled():
dir = self._dnotify.poll()
self._eventqueue.put(dir)
self._logger.info('Caught cancel event; async dnotify thread exiting')
class MtimeDirectoryNotifier(DirectoryNotifier):
def __init__(self, dirs, poll_time, logger, cancel_event=None):
DirectoryNotifier.__init__(self, dirs, logger, cancel_event=cancel_event)
self._changed = []
self._dirmap = {}
self._polltime = poll_time
for dir in dirs:
self._dirmap[dir] = os.stat(os.path.join(self._cwd, dir))[stat.ST_MTIME]
def poll(self, timeout=None):
timeout_time = None
if timeout:
timeout_time = time.time() + timeout
while self._changed == []:
if timeout_time and time.time() > timeout_time:
return None
self._logger.debug('Polling...')
for dir in self._dirmap.keys():
oldtime = self._dirmap[dir]
mtime = os.stat(os.path.join(self._cwd, dir))[stat.ST_MTIME]
if oldtime < mtime:
self._logger.debug('Directory "%s" has changed' % (dir,))
self._changed.append(dir)
self._dirmap[dir] = mtime
if self._changed == []:
for x in range(self._polltime):
if self._cancel_event.isSet():
return None
time.sleep(1)
ret = self._changed[0]
self._changed = self._changed[1:]
return ret
class DnotifyDirectoryNotifier(DirectoryNotifier):
def __init__(self, dirs, logger):
DirectoryNotifier.__init__(self, dirs, logger)
self._queue = Queue.Queue()
dnotify = DnotifyThread(self._queue, self._dirs, self._logger)
dnotify.start()
def poll(self, timeout=None):
# delete duplicates
i = self._queue.qsize()
self._logger.debug('Queue size: %d', (i,))
set = {}
while i > 0:
dir = self._queue_get(timeout)
if dir is None:
# We shouldn't have to do this; no one else is reading
# from the queue. But we do it just to be safe.
for key in set.keys():
self._queue.put(key)
return None
set[dir] = 1
i -= 1
for key in set.keys():
self._queue.put(key)
i = self._queue.qsize()
self._logger.debug('Queue size (after duplicate filter): %d', (i,))
return self._queue_get(timeout)
def _queue_get(self, timeout):
if timeout is None:
return self._queue.get()
timeout_time = time.time() + timeout
while 1:
try:
self._queue.get(0)
except Queue.Empty:
if time.time() > timeout_time:
return None
else:
time.sleep(15)
class DnotifyThread(threading.Thread):
def __init__(self, queue, dirs, logger):
threading.Thread.__init__(self)
self._queue = queue
self._dirs = dirs
self._logger = logger
def run(self):
self._logger.debug('Starting dnotify reading thread')
(infd, outfd) = os.pipe()
pid = os.fork()
if pid == 0:
os.close(infd)
misc.dup2(outfd, 1)
args = ['dnotify', '-m', '-c', '-d', '-a', '-r'] + list(self._dirs) + ['-e', 'printf', '"{}\\0"']
os.execv('/usr/bin/dnotify', args)
os.exit(1)
os.close(outfd)
stdout = os.fdopen(infd)
c = 'x'
while c != '':
curline = ''
c = stdout.read(1)
while c != '' and c != '\0':
curline += c
c = stdout.read(1)
if c == '':
break
self._logger.debug('Directory "%s" changed' % (curline,))
self._queue.put(curline)
(pid, status) = os.waitpid(pid, 0)
if status is None:
ecode = 0
else:
ecode = os.WEXITSTATUS(status)
raise DnotifyException("dnotify exited with code %s" % (ecode,))
# vim:ts=4:sw=4:et:
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