Files
picard/picard/thread.py
2006-09-23 12:40:17 +02:00

80 lines
2.6 KiB
Python

# -*- coding: utf-8 -*-
#
# Picard, the next-generation MusicBrainz tagger
# Copyright (C) 2006 Lukáš Lalinský
#
# 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
import traceback
from PyQt4 import QtCore
from picard.util import LockableDict
class HandlerThread(QtCore.QThread):
def set_handler(self, handler, args):
self.handler = handler
self.args = args
def run(self):
try:
self.handler(*self.args)
except:
traceback.print_exc()
class ThreadAssist(QtCore.QObject):
def __init__(self, parent):
QtCore.QObject.__init__(self, parent)
self.to_main = LockableDict()
self.connect(self,
QtCore.SIGNAL("proxy_to_main(int, PyObject*, PyObject*)"),
self.__on_proxy_to_main, QtCore.Qt.QueuedConnection)
self.threads = []
def __on_proxy_to_main(self, obj_id, handler, args):
handler(*args)
self.to_main.lock_for_write()
try:
del self.to_main[obj_id]
finally:
self.to_main.unlock()
def proxy_to_main(self, handler, args):
"""Invoke ``handler`` with arguments ``args`` in the main thread."""
self.to_main.lock_for_write()
try:
obj = (handler, args)
obj_id = id(obj)
self.to_main[obj_id] = obj
self.emit(QtCore.SIGNAL("proxy_to_main(int, PyObject*, PyObject*)"),
obj_id, handler, args)
finally:
self.to_main.unlock()
def spawn(self, handler, args, priority=QtCore.QThread.LowPriority):
"""Invoke ``handler`` with arguments ``args`` in a separate thread."""
thread = None
for t in self.threads:
if t.isFinished():
thread = t
break
if not thread:
thread = HandlerThread(self)
self.threads.append(thread)
thread.set_handler(handler, args)
thread.start(priority)