PyBitmessage-2021-04-27/src/singleton.py
2016-05-02 15:00:21 +02:00

66 lines
2.3 KiB
Python

#! /usr/bin/env python
import sys
import os
import errno
import shared
from multiprocessing import Process
class singleinstance:
"""
Implements a single instance application by creating a lock file at appdata.
This is based upon the singleton class from tendo https://github.com/pycontribs/tendo
which is under the Python Software Foundation License version 2
"""
def __init__(self, flavor_id="", daemon=False):
import sys
self.initialized = False
self.daemon = daemon;
self.lockfile = os.path.normpath(os.path.join(shared.appdata, 'singleton%s.lock' % flavor_id))
if not self.daemon:
# Tells the already running (if any) application to get focus.
import bitmessageqt
bitmessageqt.init()
if sys.platform == 'win32':
try:
# file already exists, we try to remove (in case previous execution was interrupted)
if os.path.exists(self.lockfile):
os.unlink(self.lockfile)
self.fd = os.open(self.lockfile, os.O_CREAT | os.O_EXCL | os.O_RDWR)
except OSError:
type, e, tb = sys.exc_info()
if e.errno == 13:
print 'Another instance of this application is already running'
sys.exit(-1)
print(e.errno)
raise
else: # non Windows
import fcntl # @UnresolvedImport
self.fp = open(self.lockfile, 'w')
try:
fcntl.lockf(self.fp, fcntl.LOCK_EX | fcntl.LOCK_NB)
except IOError:
print 'Another instance of this application is already running'
sys.exit(-1)
self.initialized = True
def __del__(self):
import sys
if not self.initialized:
return
try:
if sys.platform == 'win32':
if hasattr(self, 'fd'):
os.close(self.fd)
os.unlink(self.lockfile)
else:
import fcntl # @UnresolvedImport
fcntl.lockf(self.fp, fcntl.LOCK_UN)
if os.path.isfile(self.lockfile):
os.unlink(self.lockfile)
except Exception, e:
sys.exit(-1)