mercurial/lock.py

addremove: add back forgotten files (BC)

After running "hg forget README && hg addremove", README will still be
reported as removed, while "hg forget README && hg add README" adds it
back so it gets reported as clean. It seems like they should behave
the same. Furthermore, it seems like no files should remain untracked
after 'hg addremove && hg commit' (or 'hg commit -A'). For these
reasons, change the behavior of addremove so it does add forgotten
files back.

The problem is with scmutil._interestingfiles(), which reports the
file as removed, so scmutil.addremove() does not add it. Fix by
teaching _interestingfiles() to report forgotten files separately from
removed files and make addremove() add forgotten files back. However,
do not treat forgotten files as sources for rename detection. Note
that since removed and forgotten files are treated the same before
this change, forgotten files were considered sources for rename
detection.

Also update the other caller, marktouched(), in the same way as
addremove().

# lock.py - simple advisory locking scheme for mercurial
#
# Copyright 2005, 2006 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

import util, error
import errno, os, socket, time
import warnings

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, desc=None):
        self.vfs = vfs
        self.f = file
        self.held = 0
        self.timeout = timeout
        self.releasefn = releasefn
        self.desc = desc
        self.postrelease  = []
        self.pid = os.getpid()
        self.delay = self.lock()

    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 lock(self):
        timeout = self.timeout
        while True:
            try:
                self.trylock()
                return self.timeout - timeout
            except error.LockHeld, 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)
        while not self.held:
            try:
                self.vfs.makelock(lockname, self.f)
                self.held = 1
            except (OSError, IOError), why:
                if why.errno == errno.EEXIST:
                    locker = self.testlock()
                    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 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.

        """
        try:
            locker = self.vfs.readlock(self.f)
        except (OSError, IOError), why:
            if why.errno == errno.ENOENT:
                return None
            raise
        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 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 os.getpid() != self.pid:
                # we forked, and are not the parent
                return
            try:
                if self.releasefn:
                    self.releasefn()
            finally:
                try:
                    self.vfs.unlink(self.f)
                except OSError:
                    pass
            for callback in self.postrelease:
                callback()

def release(*locks):
    for lock in locks:
        if lock is not None:
            lock.release()