diff options
Diffstat (limited to 'lib/python2.7/site-packages/Twisted-12.2.0-py2.7-linux-x86_64.egg/twisted/python/lockfile.py')
| -rwxr-xr-x | lib/python2.7/site-packages/Twisted-12.2.0-py2.7-linux-x86_64.egg/twisted/python/lockfile.py | 214 |
1 files changed, 0 insertions, 214 deletions
diff --git a/lib/python2.7/site-packages/Twisted-12.2.0-py2.7-linux-x86_64.egg/twisted/python/lockfile.py b/lib/python2.7/site-packages/Twisted-12.2.0-py2.7-linux-x86_64.egg/twisted/python/lockfile.py deleted file mode 100755 index a0449573..00000000 --- a/lib/python2.7/site-packages/Twisted-12.2.0-py2.7-linux-x86_64.egg/twisted/python/lockfile.py +++ /dev/null @@ -1,214 +0,0 @@ -# -*- test-case-name: twisted.test.test_lockfile -*- -# Copyright (c) 2005 Divmod, Inc. -# Copyright (c) Twisted Matrix Laboratories. -# See LICENSE for details. - -""" -Filesystem-based interprocess mutex. -""" - -__metaclass__ = type - -import errno, os - -from time import time as _uniquefloat - -from twisted.python.runtime import platform - -def unique(): - return str(long(_uniquefloat() * 1000)) - -from os import rename -if not platform.isWindows(): - from os import kill - from os import symlink - from os import readlink - from os import remove as rmlink - _windows = False -else: - _windows = True - - try: - from win32api import OpenProcess - import pywintypes - except ImportError: - kill = None - else: - ERROR_ACCESS_DENIED = 5 - ERROR_INVALID_PARAMETER = 87 - - def kill(pid, signal): - try: - OpenProcess(0, 0, pid) - except pywintypes.error, e: - if e.args[0] == ERROR_ACCESS_DENIED: - return - elif e.args[0] == ERROR_INVALID_PARAMETER: - raise OSError(errno.ESRCH, None) - raise - else: - raise RuntimeError("OpenProcess is required to fail.") - - _open = file - - # XXX Implement an atomic thingamajig for win32 - def symlink(value, filename): - newlinkname = filename+"."+unique()+'.newlink' - newvalname = os.path.join(newlinkname,"symlink") - os.mkdir(newlinkname) - f = _open(newvalname,'wcb') - f.write(value) - f.flush() - f.close() - try: - rename(newlinkname, filename) - except: - os.remove(newvalname) - os.rmdir(newlinkname) - raise - - def readlink(filename): - try: - fObj = _open(os.path.join(filename,'symlink'), 'rb') - except IOError, e: - if e.errno == errno.ENOENT or e.errno == errno.EIO: - raise OSError(e.errno, None) - raise - else: - result = fObj.read() - fObj.close() - return result - - def rmlink(filename): - os.remove(os.path.join(filename, 'symlink')) - os.rmdir(filename) - - - -class FilesystemLock: - """ - A mutex. - - This relies on the filesystem property that creating - a symlink is an atomic operation and that it will - fail if the symlink already exists. Deleting the - symlink will release the lock. - - @ivar name: The name of the file associated with this lock. - - @ivar clean: Indicates whether this lock was released cleanly by its - last owner. Only meaningful after C{lock} has been called and - returns True. - - @ivar locked: Indicates whether the lock is currently held by this - object. - """ - - clean = None - locked = False - - def __init__(self, name): - self.name = name - - - def lock(self): - """ - Acquire this lock. - - @rtype: C{bool} - @return: True if the lock is acquired, false otherwise. - - @raise: Any exception os.symlink() may raise, other than - EEXIST. - """ - clean = True - while True: - try: - symlink(str(os.getpid()), self.name) - except OSError, e: - if _windows and e.errno in (errno.EACCES, errno.EIO): - # The lock is in the middle of being deleted because we're - # on Windows where lock removal isn't atomic. Give up, we - # don't know how long this is going to take. - return False - if e.errno == errno.EEXIST: - try: - pid = readlink(self.name) - except OSError, e: - if e.errno == errno.ENOENT: - # The lock has vanished, try to claim it in the - # next iteration through the loop. - continue - raise - except IOError, e: - if _windows and e.errno == errno.EACCES: - # The lock is in the middle of being - # deleted because we're on Windows where - # lock removal isn't atomic. Give up, we - # don't know how long this is going to - # take. - return False - raise - try: - if kill is not None: - kill(int(pid), 0) - except OSError, e: - if e.errno == errno.ESRCH: - # The owner has vanished, try to claim it in the next - # iteration through the loop. - try: - rmlink(self.name) - except OSError, e: - if e.errno == errno.ENOENT: - # Another process cleaned up the lock. - # Race them to acquire it in the next - # iteration through the loop. - continue - raise - clean = False - continue - raise - return False - raise - self.locked = True - self.clean = clean - return True - - - def unlock(self): - """ - Release this lock. - - This deletes the directory with the given name. - - @raise: Any exception os.readlink() may raise, or - ValueError if the lock is not owned by this process. - """ - pid = readlink(self.name) - if int(pid) != os.getpid(): - raise ValueError("Lock %r not owned by this process" % (self.name,)) - rmlink(self.name) - self.locked = False - - -def isLocked(name): - """Determine if the lock of the given name is held or not. - - @type name: C{str} - @param name: The filesystem path to the lock to test - - @rtype: C{bool} - @return: True if the lock is held, False otherwise. - """ - l = FilesystemLock(name) - result = None - try: - result = l.lock() - finally: - if result: - l.unlock() - return not result - - -__all__ = ['FilesystemLock', 'isLocked'] - |