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PyBitmessage-2024-12-09/src/singleinstance.py
surbhi 73ce4b4c83
rebase conflict fix and Ui Enhancement with dynamic addressbook updation and sent screen updation
Ui Enhancement with dynamic addressbook updation and sent screen updation

Changes made for Sent Items refresh feature with auto add new message in kivy
2019-09-17 15:38:12 +05:30

113 lines
3.6 KiB
Python

#! /usr/bin/env python
import atexit
import os
import sys
import state
try:
import fcntl # @UnresolvedImport
except ImportError:
pass
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):
self.initialized = False
self.counter = 0
self.daemon = daemon
self.lockPid = None
self.lockfile = os.path.normpath(
os.path.join(state.appdata, 'singleton%s.lock' % flavor_id))
if state.enableGUI and not state.kivy and not self.daemon and not state.curses:
# Tells the already running (if any) application to get focus.
import bitmessageqt
bitmessageqt.init()
self.lock()
self.initialized = True
atexit.register(self.cleanup)
def lock(self):
if self.lockPid is None:
self.lockPid = os.getpid()
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 | os.O_TRUNC
)
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:
pidLine = "%i\n" % self.lockPid
os.write(self.fd, pidLine)
else: # non Windows
self.fp = open(self.lockfile, 'a+')
try:
if self.daemon and self.lockPid != os.getpid():
# wait for parent to finish
fcntl.lockf(self.fp, fcntl.LOCK_EX)
else:
fcntl.lockf(self.fp, fcntl.LOCK_EX | fcntl.LOCK_NB)
self.lockPid = os.getpid()
except IOError:
print 'Another instance of this application is already running'
sys.exit(-1)
else:
pidLine = "%i\n" % self.lockPid
self.fp.truncate(0)
self.fp.write(pidLine)
self.fp.flush()
def cleanup(self):
if not self.initialized:
return
if self.daemon and self.lockPid == os.getpid():
# these are the two initial forks while daemonizing
try:
if sys.platform == 'win32':
if hasattr(self, 'fd'):
os.close(self.fd)
else:
fcntl.lockf(self.fp, fcntl.LOCK_UN)
except Exception, e:
pass
return
print "Cleaning up lockfile"
try:
if sys.platform == 'win32':
if hasattr(self, 'fd'):
os.close(self.fd)
os.unlink(self.lockfile)
else:
fcntl.lockf(self.fp, fcntl.LOCK_UN)
if os.path.isfile(self.lockfile):
os.unlink(self.lockfile)
except Exception:
pass