Mercurial > hg
view mercurial/lock.py @ 28891:ac30adb260ea
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$ hg log --graph --template '{rev} {desc|firstline}' --rev 1035:1015
o 1035 Merge with BOS
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| o 1034 Fix help output, and a few broken tests.
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| o 1033 Merge with MPM.
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| | o 1032 Get patchbomb working with tip again.
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| | o 1031 Rewrite log command. New version is faster and more featureful.
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| | o 1030 Merge with MPM.
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| | | o 1029 Emacs: implement hg-incoming, hg-outgoing and hg-push.
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| | | o 1028 Add commands.debugconfig.
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| | | o 1027 Emacs: fix up hg-log and hg-diff to operate more uniformly.
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| | | o 1026 Merge with MPM.
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| | | | o 1025 Merge with MPM.
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| | | o 1024 Sync buffers prior to doing a diff.
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o | | 1023 Minor tweak to the revgen algorithm
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o | 1022 Minor hgwebdir tweaks
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o | 1021 Add Makefile to the manifest
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o | 1020 Add default make rule
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o | 1019 Create helper functions for I/O to files in the working directory
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o | 1018 Add some aliases
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o | 1017 Fix up help for binary options
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o 1016 Teach annotate about binary files
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o 1015 Add automatic binary file detection to diff and export
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Example graph with activated option:
$ hg log --graph --template '{rev} {desc|firstline}' --rev 1035:1015
o 1035 Merge with BOS
|\
| o 1034 Fix help output, and a few broken tests.
| o 1033 Merge with MPM.
| |\
| | o 1032 Get patchbomb working with tip again.
| | o 1031 Rewrite log command. New version is faster and more featureful.
| | o 1030 Merge with MPM.
| | |\
| | | o 1029 Emacs: implement hg-incoming, hg-outgoing and hg-push.
| | | o 1028 Add commands.debugconfig.
| | | o 1027 Emacs: fix up hg-log and hg-diff to operate more uniformly.
| | | o 1026 Merge with MPM.
| | | |\
| | | | o 1025 Merge with MPM.
| | | | |
| | | | ~
| | | o 1024 Sync buffers prior to doing a diff.
| | | |
| | | ~
o | | 1023 Minor tweak to the revgen algorithm
|/ /
o | 1022 Minor hgwebdir tweaks
o | 1021 Add Makefile to the manifest
o | 1020 Add default make rule
o | 1019 Create helper functions for I/O to files in the working directory
o | 1018 Add some aliases
o | 1017 Fix up help for binary options
|/
o 1016 Teach annotate about binary files
o 1015 Add automatic binary file detection to diff and export
|
~
author | santiagopim <santiagopim@gmail.com> |
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date | Fri, 08 Apr 2016 16:42:43 +0200 |
parents | 14033c5dd261 |
children | 518c3e392f75 |
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# lock.py - simple advisory locking scheme for mercurial # # Copyright 2005, 2006 Matt Mackall <mpm@selenic.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import import contextlib import errno import socket import time import warnings from . import ( error, util, ) class lock(object): '''An advisory lock held by one process to control access to a set of files. Non-cooperating processes or incorrectly written scripts can ignore Mercurial's locking scheme and stomp all over the repository, so don't do that. Typically used via localrepository.lock() to lock the repository store (.hg/store/) or localrepository.wlock() to lock everything else under .hg/.''' # lock is symlink on platforms that support it, file on others. # symlink is used because create of directory entry and contents # are atomic even over nfs. # old-style lock: symlink to pid # new-style lock: symlink to hostname:pid _host = None def __init__(self, vfs, file, timeout=-1, releasefn=None, acquirefn=None, desc=None, inheritchecker=None, parentlock=None): self.vfs = vfs self.f = file self.held = 0 self.timeout = timeout self.releasefn = releasefn self.acquirefn = acquirefn self.desc = desc self._inheritchecker = inheritchecker self.parentlock = parentlock self._parentheld = False self._inherited = False self.postrelease = [] self.pid = self._getpid() self.delay = self.lock() if self.acquirefn: self.acquirefn() def __enter__(self): return self def __exit__(self, exc_type, exc_value, exc_tb): self.release() def __del__(self): if self.held: warnings.warn("use lock.release instead of del lock", category=DeprecationWarning, stacklevel=2) # ensure the lock will be removed # even if recursive locking did occur self.held = 1 self.release() def _getpid(self): # wrapper around util.getpid() to make testing easier return util.getpid() def lock(self): timeout = self.timeout while True: try: self._trylock() return self.timeout - timeout except error.LockHeld as inst: if timeout != 0: time.sleep(1) if timeout > 0: timeout -= 1 continue raise error.LockHeld(errno.ETIMEDOUT, inst.filename, self.desc, inst.locker) def _trylock(self): if self.held: self.held += 1 return if lock._host is None: lock._host = socket.gethostname() lockname = '%s:%s' % (lock._host, self.pid) retry = 5 while not self.held and retry: retry -= 1 try: self.vfs.makelock(lockname, self.f) self.held = 1 except (OSError, IOError) as why: if why.errno == errno.EEXIST: locker = self._readlock() # special case where a parent process holds the lock -- this # is different from the pid being different because we do # want the unlock and postrelease functions to be called, # but the lockfile to not be removed. if locker == self.parentlock: self._parentheld = True self.held = 1 return locker = self._testlock(locker) if locker is not None: raise error.LockHeld(errno.EAGAIN, self.vfs.join(self.f), self.desc, locker) else: raise error.LockUnavailable(why.errno, why.strerror, why.filename, self.desc) def _readlock(self): """read lock and return its value Returns None if no lock exists, pid for old-style locks, and host:pid for new-style locks. """ try: return self.vfs.readlock(self.f) except (OSError, IOError) as why: if why.errno == errno.ENOENT: return None raise def _testlock(self, locker): if locker is None: return None try: host, pid = locker.split(":", 1) except ValueError: return locker if host != lock._host: return locker try: pid = int(pid) except ValueError: return locker if util.testpid(pid): return locker # if locker dead, break lock. must do this with another lock # held, or can race and break valid lock. try: l = lock(self.vfs, self.f + '.break', timeout=0) self.vfs.unlink(self.f) l.release() except error.LockError: return locker def testlock(self): """return id of locker if lock is valid, else None. If old-style lock, we cannot tell what machine locker is on. with new-style lock, if locker is on this machine, we can see if locker is alive. If locker is on this machine but not alive, we can safely break lock. The lock file is only deleted when None is returned. """ locker = self._readlock() return self._testlock(locker) @contextlib.contextmanager def inherit(self): """context for the lock to be inherited by a Mercurial subprocess. Yields a string that will be recognized by the lock in the subprocess. Communicating this string to the subprocess needs to be done separately -- typically by an environment variable. """ if not self.held: raise error.LockInheritanceContractViolation( 'inherit can only be called while lock is held') if self._inherited: raise error.LockInheritanceContractViolation( 'inherit cannot be called while lock is already inherited') if self._inheritchecker is not None: self._inheritchecker() if self.releasefn: self.releasefn() if self._parentheld: lockname = self.parentlock else: lockname = '%s:%s' % (lock._host, self.pid) self._inherited = True try: yield lockname finally: if self.acquirefn: self.acquirefn() self._inherited = False def release(self): """release the lock and execute callback function if any If the lock has been acquired multiple times, the actual release is delayed to the last release call.""" if self.held > 1: self.held -= 1 elif self.held == 1: self.held = 0 if self._getpid() != self.pid: # we forked, and are not the parent return try: if self.releasefn: self.releasefn() finally: if not self._parentheld: try: self.vfs.unlink(self.f) except OSError: pass # The postrelease functions typically assume the lock is not held # at all. if not self._parentheld: for callback in self.postrelease: callback() def release(*locks): for lock in locks: if lock is not None: lock.release()