зеркало из https://github.com/mozilla/pjs.git
140 строки
4.3 KiB
Python
140 строки
4.3 KiB
Python
# ***** BEGIN LICENSE BLOCK *****
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# Version: MPL 1.1/GPL 2.0/LGPL 2.1
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#
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# The contents of this file are subject to the Mozilla Public License Version
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# 1.1 (the "License"); you may not use this file except in compliance with
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# the License. You may obtain a copy of the License at
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# http://www.mozilla.org/MPL/
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#
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# Software distributed under the License is distributed on an "AS IS" basis,
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# WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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# for the specific language governing rights and limitations under the
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# License.
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#
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# The Original Code is Mozilla build system.
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#
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# The Initial Developer of the Original Code is
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# Mozilla Foundation.
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# Portions created by the Initial Developer are Copyright (C) 2008
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# the Initial Developer. All Rights Reserved.
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#
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# Contributor(s):
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# Axel Hecht <axel@pike.org>
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#
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# Alternatively, the contents of this file may be used under the terms of
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# either the GNU General Public License Version 2 or later (the "GPL"), or
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# the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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# in which case the provisions of the GPL or the LGPL are applicable instead
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# of those above. If you wish to allow use of your version of this file only
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# under the terms of either the GPL or the LGPL, and not to allow others to
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# use your version of this file under the terms of the MPL, indicate your
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# decision by deleting the provisions above and replace them with the notice
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# and other provisions required by the GPL or the LGPL. If you do not delete
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# the provisions above, a recipient may use your version of this file under
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# the terms of any one of the MPL, the GPL or the LGPL.
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#
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# ***** END LICENSE BLOCK *****
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'''Utility methods to be used by python build infrastructure.
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'''
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import os
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import errno
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import sys
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import time
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import stat
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class LockFile(object):
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'''LockFile is used by the lockFile method to hold the lock.
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This object should not be used directly, but only through
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the lockFile method below.
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'''
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def __init__(self, lockfile):
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self.lockfile = lockfile
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def __del__(self):
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os.remove(self.lockfile)
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def lockFile(lockfile, max_wait = 600):
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'''Create and hold a lockfile of the given name, with the given timeout.
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To release the lock, delete the returned object.
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'''
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while True:
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try:
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fd = os.open(lockfile, os.O_EXCL | os.O_RDWR | os.O_CREAT)
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# we created the lockfile, so we're the owner
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break
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except OSError, e:
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if e.errno != errno.EEXIST:
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# should not occur
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raise
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try:
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# the lock file exists, try to stat it to get its age
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# and read its contents to report the owner PID
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f = open(lockfile, "r")
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s = os.stat(lockfile)
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except OSError, e:
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if e.errno != errno.ENOENT:
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sys.exit("%s exists but stat() failed: %s" %
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(lockfile, e.strerror))
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# we didn't create the lockfile, so it did exist, but it's
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# gone now. Just try again
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continue
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# we didn't create the lockfile and it's still there, check
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# its age
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now = int(time.time())
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if now - s[stat.ST_MTIME] > max_wait:
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pid = f.readline()
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sys.exit("%s has been locked for more than " \
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"%d seconds (PID %s)" % (lockfile, max_wait,
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pid))
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# it's not been locked too long, wait a while and retry
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f.close()
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time.sleep(1)
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# if we get here. we have the lockfile. Convert the os.open file
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# descriptor into a Python file object and record our PID in it
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f = os.fdopen(fd, "w")
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f.write("%d\n" % os.getpid())
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f.close()
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return LockFile(lockfile)
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class pushback_iter(object):
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'''Utility iterator that can deal with pushed back elements.
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This behaves like a regular iterable, just that you can call
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iter.pushback(item)
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to get the givem item as next item in the iteration.
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'''
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def __init__(self, iterable):
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self.it = iter(iterable)
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self.pushed_back = []
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def __iter__(self):
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return self
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def __nonzero__(self):
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if self.pushed_back:
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return True
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try:
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self.pushed_back.insert(0, self.it.next())
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except StopIteration:
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return False
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else:
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return True
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def next(self):
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if self.pushed_back:
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return self.pushed_back.pop()
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return self.it.next()
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def pushback(self, item):
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self.pushed_back.append(item)
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