зеркало из https://github.com/mozilla/pjs.git
121 строка
3.4 KiB
Python
121 строка
3.4 KiB
Python
# This Source Code Form is subject to the terms of the Mozilla Public
|
|
# License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
|
|
|
|
'''Utility methods to be used by python build infrastructure.
|
|
'''
|
|
|
|
import os
|
|
import errno
|
|
import sys
|
|
import time
|
|
import stat
|
|
|
|
class LockFile(object):
|
|
'''LockFile is used by the lockFile method to hold the lock.
|
|
|
|
This object should not be used directly, but only through
|
|
the lockFile method below.
|
|
'''
|
|
def __init__(self, lockfile):
|
|
self.lockfile = lockfile
|
|
def __del__(self):
|
|
while True:
|
|
try:
|
|
os.remove(self.lockfile)
|
|
break
|
|
except OSError, e:
|
|
if e.errno == errno.EACCES:
|
|
# another process probably has the file open, we'll retry.
|
|
# just a short sleep since we want to drop the lock ASAP
|
|
# (but we need to let some other process close the file first)
|
|
time.sleep(0.1)
|
|
else:
|
|
# re-raise unknown errors
|
|
raise
|
|
|
|
def lockFile(lockfile, max_wait = 600):
|
|
'''Create and hold a lockfile of the given name, with the given timeout.
|
|
|
|
To release the lock, delete the returned object.
|
|
'''
|
|
while True:
|
|
try:
|
|
fd = os.open(lockfile, os.O_EXCL | os.O_RDWR | os.O_CREAT)
|
|
# we created the lockfile, so we're the owner
|
|
break
|
|
except OSError, e:
|
|
if e.errno == errno.EEXIST or \
|
|
(sys.platform == "win32" and e.errno == errno.EACCES):
|
|
pass
|
|
else:
|
|
# should not occur
|
|
raise
|
|
|
|
try:
|
|
# the lock file exists, try to stat it to get its age
|
|
# and read its contents to report the owner PID
|
|
f = open(lockfile, "r")
|
|
s = os.stat(lockfile)
|
|
except EnvironmentError, e:
|
|
if e.errno == errno.ENOENT or e.errno == errno.EACCES:
|
|
# we didn't create the lockfile, so it did exist, but it's
|
|
# gone now. Just try again
|
|
continue
|
|
sys.exit("%s exists but stat() failed: %s" %
|
|
(lockfile, e.strerror))
|
|
|
|
# we didn't create the lockfile and it's still there, check
|
|
# its age
|
|
now = int(time.time())
|
|
if now - s[stat.ST_MTIME] > max_wait:
|
|
pid = f.readline().rstrip()
|
|
sys.exit("%s has been locked for more than " \
|
|
"%d seconds (PID %s)" % (lockfile, max_wait,
|
|
pid))
|
|
|
|
# it's not been locked too long, wait a while and retry
|
|
f.close()
|
|
time.sleep(1)
|
|
|
|
# if we get here. we have the lockfile. Convert the os.open file
|
|
# descriptor into a Python file object and record our PID in it
|
|
|
|
f = os.fdopen(fd, "w")
|
|
f.write("%d\n" % os.getpid())
|
|
f.close()
|
|
return LockFile(lockfile)
|
|
|
|
class pushback_iter(object):
|
|
'''Utility iterator that can deal with pushed back elements.
|
|
|
|
This behaves like a regular iterable, just that you can call
|
|
iter.pushback(item)
|
|
to get the givem item as next item in the iteration.
|
|
'''
|
|
def __init__(self, iterable):
|
|
self.it = iter(iterable)
|
|
self.pushed_back = []
|
|
|
|
def __iter__(self):
|
|
return self
|
|
|
|
def __nonzero__(self):
|
|
if self.pushed_back:
|
|
return True
|
|
|
|
try:
|
|
self.pushed_back.insert(0, self.it.next())
|
|
except StopIteration:
|
|
return False
|
|
else:
|
|
return True
|
|
|
|
def next(self):
|
|
if self.pushed_back:
|
|
return self.pushed_back.pop()
|
|
return self.it.next()
|
|
|
|
def pushback(self, item):
|
|
self.pushed_back.append(item)
|