#!/usr/bin/env python
# -*- coding: iso-8859-15 -*-

""" Gestion de lock 

Copyright (C) Frédéric Pauget
Licence : GPLv2
"""

import os,string,time,sys, affich_tools

def make_lock(lock_name, lock_comment='') :
    """ Création d'un lock """
    lock_file = '/var/lock/' + lock_name
    if os.path.isfile(lock_file) :
	### Lock existant
	
	# Lecture du lock
	fd = open(lock_file, "r")
	pid= fd.readline().strip()
	fd.close()
	    
	# Informations sur le processus lockant
	if os.system( "ps %s > /dev/null 2>&1" % pid ) :
	    # Le script lockant ne tourne plus
	    os.remove(lock_file)
	else :
	    # Il faut attendre
	    a = affich_tools.anim('\tattente du lock')
	    for i in range(8) :
		time.sleep(1)
		a.cycle()
	    sys.stdout.write('\r')
	    return make_lock(lock_name, lock_comment)
	    
    ### Prise du lock
    lock_fd=open(lock_file, "w")
    lock_fd.write("%s\n%s" % (os.getpid(), lock_comment) )
    lock_fd.close()

def remove_lock( lock_name ) :
    """ Destruction du lock """
    lock_file = '/var/lock/' + lock_name
    try :
	fd = open(lock_file, "r")
	if fd.readline().strip()=="%s" % os.getpid():
	    os.remove(lock_file)
	    fd.close()
    except :
	None