'''
Do not start program, if pidfile exists and is an active process.

(c) 2011-2012 Jan ONDREJ (SAL) <ondrejj(at)salstar.sk>

 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.
'''

import os, sys, atexit, paths

def unlink_pidfile():
    try:
      os.unlink(paths.pid_file)
    except:
      pass

def exit(msg, es=1):
    if "-m" in sys.argv or "--multi" in sys.argv:
      print "SVplayer process already running, but multiple instances allowed."
    else:
      print msg
      sys.exit(es)

def savepid():
    open(paths.pid_file, "wt").write(pid)
    atexit.register(unlink_pidfile)

pid = str(os.getpid())
if os.path.isfile(paths.pid_file):
  fpid = open(paths.pid_file, "rt").read().strip()
  # check if process really exists
  if sys.platform.startswith('linux'):
    if os.path.exists("/proc/%s" % fpid):
      exit("SVPlayer pid [%s] already running, exiting..." % fpid)
    else:
      print "SVPlayer pid file exists, but there is no such process with",
      print "this pid, ignoring."
      savepid()
  elif sys.platform.startswith('win'):
    exit("Pid file exists, please remove it if SVPlayer crashed.")
else:
  savepid()