view mercurial/bookmarks.py @ 17682:829919ef894a stable

lock: fixed race condition in trylock/testlock (issue3506)

Suppose the following scenario:

1. Process A takes the lock (e.g. on commit).
2. Process B wants to grab the lock. Since lock file exists
   the exception is raised. In the catch block the testlock
   function is called.
3. Process A releases the lock.
4. Process B tries to read the lock file as a part of testlock
   function. This results in OSError (ENOENT) and since we're
   not inside the exception handler function this is propagated
   and aborts the whole operation.

To fix this we now check in testlock function whether lock file
actually exists and if not (i.e. if readlock fails) we just return.

# Mercurial bookmark support code
#
# Copyright 2008 David Soria Parra <[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.

from mercurial.i18n import _
from mercurial.node import hex
from mercurial import encoding, error, util
import errno, os

def valid(mark):
    for c in (':', '\0', '\n', '\r'):
        if c in mark:
            return False
    return True

def read(repo):
    '''Parse .hg/bookmarks file and return a dictionary

    Bookmarks are stored as {HASH}\\s{NAME}\\n (localtags format) values
    in the .hg/bookmarks file.
    Read the file and return a (name=>nodeid) dictionary
    '''
    bookmarks = {}
    try:
        for line in repo.opener('bookmarks'):
            line = line.strip()
            if not line:
                continue
            if ' ' not in line:
                repo.ui.warn(_('malformed line in .hg/bookmarks: %r\n') % line)
                continue
            sha, refspec = line.split(' ', 1)
            refspec = encoding.tolocal(refspec)
            try:
                bookmarks[refspec] = repo.changelog.lookup(sha)
            except LookupError:
                pass
    except IOError, inst:
        if inst.errno != errno.ENOENT:
            raise
    return bookmarks

def readcurrent(repo):
    '''Get the current bookmark

    If we use gittishsh branches we have a current bookmark that
    we are on. This function returns the name of the bookmark. It
    is stored in .hg/bookmarks.current
    '''
    mark = None
    try:
        file = repo.opener('bookmarks.current')
    except IOError, inst:
        if inst.errno != errno.ENOENT:
            raise
        return None
    try:
        # No readline() in posixfile_nt, reading everything is cheap
        mark = encoding.tolocal((file.readlines() or [''])[0])
        if mark == '' or mark not in repo._bookmarks:
            mark = None
    finally:
        file.close()
    return mark

def write(repo):
    '''Write bookmarks

    Write the given bookmark => hash dictionary to the .hg/bookmarks file
    in a format equal to those of localtags.

    We also store a backup of the previous state in undo.bookmarks that
    can be copied back on rollback.
    '''
    refs = repo._bookmarks

    if repo._bookmarkcurrent not in refs:
        setcurrent(repo, None)
    for mark in refs.keys():
        if not valid(mark):
            raise util.Abort(_("bookmark '%s' contains illegal "
                "character" % mark))

    wlock = repo.wlock()
    try:

        file = repo.opener('bookmarks', 'w', atomictemp=True)
        for refspec, node in refs.iteritems():
            file.write("%s %s\n" % (hex(node), encoding.fromlocal(refspec)))
        file.close()

        # touch 00changelog.i so hgweb reloads bookmarks (no lock needed)
        try:
            os.utime(repo.sjoin('00changelog.i'), None)
        except OSError:
            pass

    finally:
        wlock.release()

def setcurrent(repo, mark):
    '''Set the name of the bookmark that we are currently on

    Set the name of the bookmark that we are on (hg update <bookmark>).
    The name is recorded in .hg/bookmarks.current
    '''
    current = repo._bookmarkcurrent
    if current == mark:
        return

    if mark not in repo._bookmarks:
        mark = ''
    if not valid(mark):
        raise util.Abort(_("bookmark '%s' contains illegal "
            "character" % mark))

    wlock = repo.wlock()
    try:
        file = repo.opener('bookmarks.current', 'w', atomictemp=True)
        file.write(encoding.fromlocal(mark))
        file.close()
    finally:
        wlock.release()
    repo._bookmarkcurrent = mark

def unsetcurrent(repo):
    wlock = repo.wlock()
    try:
        try:
            util.unlink(repo.join('bookmarks.current'))
            repo._bookmarkcurrent = None
        except OSError, inst:
            if inst.errno != errno.ENOENT:
                raise
    finally:
        wlock.release()

def updatecurrentbookmark(repo, oldnode, curbranch):
    try:
        return update(repo, oldnode, repo.branchtip(curbranch))
    except error.RepoLookupError:
        if curbranch == "default": # no default branch!
            return update(repo, oldnode, repo.lookup("tip"))
        else:
            raise util.Abort(_("branch %s not found") % curbranch)

def update(repo, parents, node):
    marks = repo._bookmarks
    update = False
    cur = repo._bookmarkcurrent
    if not cur:
        return False

    toupdate = [b for b in marks if b.split('@', 1)[0] == cur.split('@', 1)[0]]
    for mark in toupdate:
        if mark and marks[mark] in parents:
            old = repo[marks[mark]]
            new = repo[node]
            if new in old.descendants() and mark == cur:
                marks[cur] = new.node()
                update = True
            if mark != cur:
                del marks[mark]
    if update:
        repo._writebookmarks(marks)
    return update

def listbookmarks(repo):
    # We may try to list bookmarks on a repo type that does not
    # support it (e.g., statichttprepository).
    marks = getattr(repo, '_bookmarks', {})

    d = {}
    for k, v in marks.iteritems():
        # don't expose local divergent bookmarks
        if '@' not in k or k.endswith('@'):
            d[k] = hex(v)
    return d

def pushbookmark(repo, key, old, new):
    w = repo.wlock()
    try:
        marks = repo._bookmarks
        if hex(marks.get(key, '')) != old:
            return False
        if new == '':
            del marks[key]
        else:
            if new not in repo:
                return False
            marks[key] = repo[new].node()
        write(repo)
        return True
    finally:
        w.release()

def updatefromremote(ui, repo, remote, path):
    ui.debug("checking for updated bookmarks\n")
    rb = remote.listkeys('bookmarks')
    changed = False
    for k in rb.keys():
        if k in repo._bookmarks:
            nr, nl = rb[k], repo._bookmarks[k]
            if nr in repo:
                cr = repo[nr]
                cl = repo[nl]
                if cl.rev() >= cr.rev():
                    continue
                if cr in cl.descendants():
                    repo._bookmarks[k] = cr.node()
                    changed = True
                    ui.status(_("updating bookmark %s\n") % k)
                else:
                    # find a unique @ suffix
                    for x in range(1, 100):
                        n = '%s@%d' % (k, x)
                        if n not in repo._bookmarks:
                            break
                    # try to use an @pathalias suffix
                    # if an @pathalias already exists, we overwrite (update) it
                    for p, u in ui.configitems("paths"):
                        if path == u:
                            n = '%s@%s' % (k, p)

                    repo._bookmarks[n] = cr.node()
                    changed = True
                    ui.warn(_("divergent bookmark %s stored as %s\n") % (k, n))
        elif rb[k] in repo:
            # add remote bookmarks for changes we already have
            repo._bookmarks[k] = repo[rb[k]].node()
            changed = True
            ui.status(_("adding remote bookmark %s\n") % k)

    if changed:
        write(repo)

def diff(ui, repo, remote):
    ui.status(_("searching for changed bookmarks\n"))

    lmarks = repo.listkeys('bookmarks')
    rmarks = remote.listkeys('bookmarks')

    diff = sorted(set(rmarks) - set(lmarks))
    for k in diff:
        mark = ui.debugflag and rmarks[k] or rmarks[k][:12]
        ui.write("   %-25s %s\n" % (k, mark))

    if len(diff) <= 0:
        ui.status(_("no changed bookmarks found\n"))
        return 1
    return 0