bookmarks: document getbkfile method

I'm working on bmstore again, and this function gave me a moment's
pause. Document it to save future readers from any undue confusion.

mercurial/bookmarks.py

@@ -1,585 +1,591 b''
 # 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 __future__ import absolute_import
 
 import errno
 import os
 
 from .i18n import _
 from .node import (
     bin,
     hex,
 )
 from . import (
     encoding,
     lock as lockmod,
     obsolete,
     util,
 )
 
 class bmstore(dict):
     """Storage for bookmarks.
 
     This object should do all bookmark reads and writes, so that it's
     fairly simple to replace the storage underlying bookmarks without
     having to clone the logic surrounding bookmarks.
 
     This particular bmstore implementation stores bookmarks as
     {hash}\s{name}\n (the same format as localtags) in
     .hg/bookmarks. The mapping is stored as {name: nodeid}.
 
     This class does NOT handle the "active" bookmark state at this
     time.
     """
 
     def __init__(self, repo):
         dict.__init__(self)
         self._repo = repo
         try:
             bkfile = self.getbkfile(repo)
             for line in bkfile:
                 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:
                     self[refspec] = repo.changelog.lookup(sha)
                 except LookupError:
                     pass
         except IOError as inst:
             if inst.errno != errno.ENOENT:
                 raise
 
     def getbkfile(self, repo):
+        """Hook so that extensions that mess with the store can hook bm storage.
+
+        For core, this just handles wether we should see pending
+        bookmarks or the committed ones. Other extensions (like share)
+        may need to tweak this behavior further.
+        """
         bkfile = None
         if 'HG_PENDING' in os.environ:
             try:
                 bkfile = repo.vfs('bookmarks.pending')
             except IOError as inst:
                 if inst.errno != errno.ENOENT:
                     raise
         if bkfile is None:
             bkfile = repo.vfs('bookmarks')
         return bkfile
 
     def recordchange(self, tr):
         """record that bookmarks have been changed in a transaction
 
         The transaction is then responsible for updating the file content."""
         tr.addfilegenerator('bookmarks', ('bookmarks',), self._write,
                             location='plain')
         tr.hookargs['bookmark_moved'] = '1'
 
     def write(self):
         '''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.
         '''
         repo = self._repo
         if (repo.ui.configbool('devel', 'all-warnings')
                 or repo.ui.configbool('devel', 'check-locks')):
             l = repo._wlockref and repo._wlockref()
             if l is None or not l.held:
                 repo.ui.develwarn('bookmarks write with no wlock')
 
         tr = repo.currenttransaction()
         if tr:
             self.recordchange(tr)
             # invalidatevolatilesets() is omitted because this doesn't
             # write changes out actually
             return
 
         self._writerepo(repo)
         repo.invalidatevolatilesets()
 
     def _writerepo(self, repo):
         """Factored out for extensibility"""
         if repo._activebookmark not in self:
             deactivate(repo)
 
         wlock = repo.wlock()
         try:
 
             file = repo.vfs('bookmarks', 'w', atomictemp=True)
             self._write(file)
             file.close()
 
         finally:
             wlock.release()
 
     def _write(self, fp):
         for name, node in self.iteritems():
             fp.write("%s %s\n" % (hex(node), encoding.fromlocal(name)))
 
 def readactive(repo):
     """
     Get the active bookmark. We can have an active bookmark that updates
     itself as we commit. This function returns the name of that bookmark.
     It is stored in .hg/bookmarks.current
     """
     mark = None
     try:
         file = repo.vfs('bookmarks.current')
     except IOError as inst:
         if inst.errno != errno.ENOENT:
             raise
         return None
     try:
         # No readline() in osutil.posixfile, 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 activate(repo, mark):
     """
     Set the given bookmark to be 'active', meaning that this bookmark will
     follow new commits that are made.
     The name is recorded in .hg/bookmarks.current
     """
     if mark not in repo._bookmarks:
         raise AssertionError('bookmark %s does not exist!' % mark)
 
     active = repo._activebookmark
     if active == mark:
         return
 
     wlock = repo.wlock()
     try:
         file = repo.vfs('bookmarks.current', 'w', atomictemp=True)
         file.write(encoding.fromlocal(mark))
         file.close()
     finally:
         wlock.release()
     repo._activebookmark = mark
 
 def deactivate(repo):
     """
     Unset the active bookmark in this repository.
     """
     wlock = repo.wlock()
     try:
         repo.vfs.unlink('bookmarks.current')
         repo._activebookmark = None
     except OSError as inst:
         if inst.errno != errno.ENOENT:
             raise
     finally:
         wlock.release()
 
 def isactivewdirparent(repo):
     """
     Tell whether the 'active' bookmark (the one that follows new commits)
     points to one of the parents of the current working directory (wdir).
 
     While this is normally the case, it can on occasion be false; for example,
     immediately after a pull, the active bookmark can be moved to point
     to a place different than the wdir. This is solved by running `hg update`.
     """
     mark = repo._activebookmark
     marks = repo._bookmarks
     parents = [p.node() for p in repo[None].parents()]
     return (mark in marks and marks[mark] in parents)
 
 def deletedivergent(repo, deletefrom, bm):
     '''Delete divergent versions of bm on nodes in deletefrom.
 
     Return True if at least one bookmark was deleted, False otherwise.'''
     deleted = False
     marks = repo._bookmarks
     divergent = [b for b in marks if b.split('@', 1)[0] == bm.split('@', 1)[0]]
     for mark in divergent:
         if mark == '@' or '@' not in mark:
             # can't be divergent by definition
             continue
         if mark and marks[mark] in deletefrom:
             if mark != bm:
                 del marks[mark]
                 deleted = True
     return deleted
 
 def calculateupdate(ui, repo, checkout):
     '''Return a tuple (targetrev, movemarkfrom) indicating the rev to
     check out and where to move the active bookmark from, if needed.'''
     movemarkfrom = None
     if checkout is None:
         activemark = repo._activebookmark
         if isactivewdirparent(repo):
             movemarkfrom = repo['.'].node()
         elif activemark:
             ui.status(_("updating to active bookmark %s\n") % activemark)
             checkout = activemark
     return (checkout, movemarkfrom)
 
 def update(repo, parents, node):
     deletefrom = parents
     marks = repo._bookmarks
     update = False
     active = repo._activebookmark
     if not active:
         return False
 
     if marks[active] in parents:
         new = repo[node]
         divs = [repo[b] for b in marks
                 if b.split('@', 1)[0] == active.split('@', 1)[0]]
         anc = repo.changelog.ancestors([new.rev()])
         deletefrom = [b.node() for b in divs if b.rev() in anc or b == new]
         if validdest(repo, repo[marks[active]], new):
             marks[active] = new.node()
             update = True
 
     if deletedivergent(repo, deletefrom, active):
         update = True
 
     if update:
         lock = tr = None
         try:
             lock = repo.lock()
             tr = repo.transaction('bookmark')
             marks.recordchange(tr)
             tr.close()
         finally:
             lockmod.release(tr, lock)
     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 = {}
     hasnode = repo.changelog.hasnode
     for k, v in marks.iteritems():
         # don't expose local divergent bookmarks
         if hasnode(v) and ('@' not in k or k.endswith('@')):
             d[k] = hex(v)
     return d
 
 def pushbookmark(repo, key, old, new):
     w = l = tr = None
     try:
         w = repo.wlock()
         l = repo.lock()
         tr = repo.transaction('bookmarks')
         marks = repo._bookmarks
         existing = hex(marks.get(key, ''))
         if existing != old and existing != new:
             return False
         if new == '':
             del marks[key]
         else:
             if new not in repo:
                 return False
             marks[key] = repo[new].node()
         marks.recordchange(tr)
         tr.close()
         return True
     finally:
         lockmod.release(tr, l, w)
 
 def compare(repo, srcmarks, dstmarks,
             srchex=None, dsthex=None, targets=None):
     '''Compare bookmarks between srcmarks and dstmarks
 
     This returns tuple "(addsrc, adddst, advsrc, advdst, diverge,
     differ, invalid)", each are list of bookmarks below:
 
     :addsrc:  added on src side (removed on dst side, perhaps)
     :adddst:  added on dst side (removed on src side, perhaps)
     :advsrc:  advanced on src side
     :advdst:  advanced on dst side
     :diverge: diverge
     :differ:  changed, but changeset referred on src is unknown on dst
     :invalid: unknown on both side
     :same:    same on both side
 
     Each elements of lists in result tuple is tuple "(bookmark name,
     changeset ID on source side, changeset ID on destination
     side)". Each changeset IDs are 40 hexadecimal digit string or
     None.
 
     Changeset IDs of tuples in "addsrc", "adddst", "differ" or
      "invalid" list may be unknown for repo.
 
     This function expects that "srcmarks" and "dstmarks" return
     changeset ID in 40 hexadecimal digit string for specified
     bookmark. If not so (e.g. bmstore "repo._bookmarks" returning
     binary value), "srchex" or "dsthex" should be specified to convert
     into such form.
 
     If "targets" is specified, only bookmarks listed in it are
     examined.
     '''
     if not srchex:
         srchex = lambda x: x
     if not dsthex:
         dsthex = lambda x: x
 
     if targets:
         bset = set(targets)
     else:
         srcmarkset = set(srcmarks)
         dstmarkset = set(dstmarks)
         bset = srcmarkset | dstmarkset
 
     results = ([], [], [], [], [], [], [], [])
     addsrc = results[0].append
     adddst = results[1].append
     advsrc = results[2].append
     advdst = results[3].append
     diverge = results[4].append
     differ = results[5].append
     invalid = results[6].append
     same = results[7].append
 
     for b in sorted(bset):
         if b not in srcmarks:
             if b in dstmarks:
                 adddst((b, None, dsthex(dstmarks[b])))
             else:
                 invalid((b, None, None))
         elif b not in dstmarks:
             addsrc((b, srchex(srcmarks[b]), None))
         else:
             scid = srchex(srcmarks[b])
             dcid = dsthex(dstmarks[b])
             if scid == dcid:
                 same((b, scid, dcid))
             elif scid in repo and dcid in repo:
                 sctx = repo[scid]
                 dctx = repo[dcid]
                 if sctx.rev() < dctx.rev():
                     if validdest(repo, sctx, dctx):
                         advdst((b, scid, dcid))
                     else:
                         diverge((b, scid, dcid))
                 else:
                     if validdest(repo, dctx, sctx):
                         advsrc((b, scid, dcid))
                     else:
                         diverge((b, scid, dcid))
             else:
                 # it is too expensive to examine in detail, in this case
                 differ((b, scid, dcid))
 
     return results
 
 def _diverge(ui, b, path, localmarks, remotenode):
     '''Return appropriate diverged bookmark for specified ``path``
 
     This returns None, if it is failed to assign any divergent
     bookmark name.
 
     This reuses already existing one with "@number" suffix, if it
     refers ``remotenode``.
     '''
     if b == '@':
         b = ''
     # try to use an @pathalias suffix
     # if an @pathalias already exists, we overwrite (update) it
     if path.startswith("file:"):
         path = util.url(path).path
     for p, u in ui.configitems("paths"):
         if u.startswith("file:"):
             u = util.url(u).path
         if path == u:
             return '%s@%s' % (b, p)
 
     # assign a unique "@number" suffix newly
     for x in range(1, 100):
         n = '%s@%d' % (b, x)
         if n not in localmarks or localmarks[n] == remotenode:
             return n
 
     return None
 
 def updatefromremote(ui, repo, remotemarks, path, trfunc, explicit=()):
     ui.debug("checking for updated bookmarks\n")
     localmarks = repo._bookmarks
     (addsrc, adddst, advsrc, advdst, diverge, differ, invalid, same
      ) = compare(repo, remotemarks, localmarks, dsthex=hex)
 
     status = ui.status
     warn = ui.warn
     if ui.configbool('ui', 'quietbookmarkmove', False):
         status = warn = ui.debug
 
     explicit = set(explicit)
     changed = []
     for b, scid, dcid in addsrc:
         if scid in repo: # add remote bookmarks for changes we already have
             changed.append((b, bin(scid), status,
                             _("adding remote bookmark %s\n") % (b)))
         elif b in explicit:
             explicit.remove(b)
             ui.warn(_("remote bookmark %s points to locally missing %s\n")
                     % (b, scid[:12]))
 
     for b, scid, dcid in advsrc:
         changed.append((b, bin(scid), status,
                         _("updating bookmark %s\n") % (b)))
     # remove normal movement from explicit set
     explicit.difference_update(d[0] for d in changed)
 
     for b, scid, dcid in diverge:
         if b in explicit:
             explicit.discard(b)
             changed.append((b, bin(scid), status,
                             _("importing bookmark %s\n") % (b)))
         else:
             snode = bin(scid)
             db = _diverge(ui, b, path, localmarks, snode)
             if db:
                 changed.append((db, snode, warn,
                                 _("divergent bookmark %s stored as %s\n") %
                                 (b, db)))
             else:
                 warn(_("warning: failed to assign numbered name "
                        "to divergent bookmark %s\n") % (b))
     for b, scid, dcid in adddst + advdst:
         if b in explicit:
             explicit.discard(b)
             changed.append((b, bin(scid), status,
                             _("importing bookmark %s\n") % (b)))
     for b, scid, dcid in differ:
         if b in explicit:
             explicit.remove(b)
             ui.warn(_("remote bookmark %s points to locally missing %s\n")
                     % (b, scid[:12]))
 
     if changed:
         tr = trfunc()
         for b, node, writer, msg in sorted(changed):
             localmarks[b] = node
             writer(msg)
         localmarks.recordchange(tr)
 
 def incoming(ui, repo, other):
     '''Show bookmarks incoming from other to repo
     '''
     ui.status(_("searching for changed bookmarks\n"))
 
     r = compare(repo, other.listkeys('bookmarks'), repo._bookmarks,
                 dsthex=hex)
     addsrc, adddst, advsrc, advdst, diverge, differ, invalid, same = r
 
     incomings = []
     if ui.debugflag:
         getid = lambda id: id
     else:
         getid = lambda id: id[:12]
     if ui.verbose:
         def add(b, id, st):
             incomings.append("   %-25s %s %s\n" % (b, getid(id), st))
     else:
         def add(b, id, st):
             incomings.append("   %-25s %s\n" % (b, getid(id)))
     for b, scid, dcid in addsrc:
         # i18n: "added" refers to a bookmark
         add(b, scid, _('added'))
     for b, scid, dcid in advsrc:
         # i18n: "advanced" refers to a bookmark
         add(b, scid, _('advanced'))
     for b, scid, dcid in diverge:
         # i18n: "diverged" refers to a bookmark
         add(b, scid, _('diverged'))
     for b, scid, dcid in differ:
         # i18n: "changed" refers to a bookmark
         add(b, scid, _('changed'))
 
     if not incomings:
         ui.status(_("no changed bookmarks found\n"))
         return 1
 
     for s in sorted(incomings):
         ui.write(s)
 
     return 0
 
 def outgoing(ui, repo, other):
     '''Show bookmarks outgoing from repo to other
     '''
     ui.status(_("searching for changed bookmarks\n"))
 
     r = compare(repo, repo._bookmarks, other.listkeys('bookmarks'),
                 srchex=hex)
     addsrc, adddst, advsrc, advdst, diverge, differ, invalid, same = r
 
     outgoings = []
     if ui.debugflag:
         getid = lambda id: id
     else:
         getid = lambda id: id[:12]
     if ui.verbose:
         def add(b, id, st):
             outgoings.append("   %-25s %s %s\n" % (b, getid(id), st))
     else:
         def add(b, id, st):
             outgoings.append("   %-25s %s\n" % (b, getid(id)))
     for b, scid, dcid in addsrc:
         # i18n: "added refers to a bookmark
         add(b, scid, _('added'))
     for b, scid, dcid in adddst:
         # i18n: "deleted" refers to a bookmark
         add(b, ' ' * 40, _('deleted'))
     for b, scid, dcid in advsrc:
         # i18n: "advanced" refers to a bookmark
         add(b, scid, _('advanced'))
     for b, scid, dcid in diverge:
         # i18n: "diverged" refers to a bookmark
         add(b, scid, _('diverged'))
     for b, scid, dcid in differ:
         # i18n: "changed" refers to a bookmark
         add(b, scid, _('changed'))
 
     if not outgoings:
         ui.status(_("no changed bookmarks found\n"))
         return 1
 
     for s in sorted(outgoings):
         ui.write(s)
 
     return 0
 
 def summary(repo, other):
     '''Compare bookmarks between repo and other for "hg summary" output
 
     This returns "(# of incoming, # of outgoing)" tuple.
     '''
     r = compare(repo, other.listkeys('bookmarks'), repo._bookmarks,
                 dsthex=hex)
     addsrc, adddst, advsrc, advdst, diverge, differ, invalid, same = r
     return (len(addsrc), len(adddst))
 
 def validdest(repo, old, new):
     """Is the new bookmark destination a valid update from the old one"""
     repo = repo.unfiltered()
     if old == new:
         # Old == new -> nothing to update.
         return False
     elif not old:
         # old is nullrev, anything is valid.
         # (new != nullrev has been excluded by the previous check)
         return True
     elif repo.obsstore:
         return new.node() in obsolete.foreground(repo, [old.node()])
     else:
         # still an independent clause as it is lazier (and therefore faster)
         return old.descendant(new)