cmdutil: return a dummy, closable file object if it cannot be duped

If the ui I/O descriptors aren't real descriptors, they cannot be duped.

Instead, we return a wrapper object that behaves the same, and
can be closed (by overriding close and doing nothing).

mercurial/cmdutil.py

@@ -1,1228 +1,1243 b''
 # cmdutil.py - help for command processing in mercurial
 #
 # Copyright 2005-2007 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.
 
 from node import hex, nullid, nullrev, short
 from i18n import _
 import os, sys, errno, re, tempfile
 import util, scmutil, templater, patch, error, templatekw, revlog
 import match as matchmod
 import subrepo
 
 def parsealiases(cmd):
     return cmd.lstrip("^").split("|")
 
 def findpossible(cmd, table, strict=False):
     """
     Return cmd -> (aliases, command table entry)
     for each matching command.
     Return debug commands (or their aliases) only if no normal command matches.
     """
     choice = {}
     debugchoice = {}
     for e in table.keys():
         aliases = parsealiases(e)
         found = None
         if cmd in aliases:
             found = cmd
         elif not strict:
             for a in aliases:
                 if a.startswith(cmd):
                     found = a
                     break
         if found is not None:
             if aliases[0].startswith("debug") or found.startswith("debug"):
                 debugchoice[found] = (aliases, table[e])
             else:
                 choice[found] = (aliases, table[e])
 
     if not choice and debugchoice:
         choice = debugchoice
 
     return choice
 
 def findcmd(cmd, table, strict=True):
     """Return (aliases, command table entry) for command string."""
     choice = findpossible(cmd, table, strict)
 
     if cmd in choice:
         return choice[cmd]
 
     if len(choice) > 1:
         clist = choice.keys()
         clist.sort()
         raise error.AmbiguousCommand(cmd, clist)
 
     if choice:
         return choice.values()[0]
 
     raise error.UnknownCommand(cmd)
 
 def findrepo(p):
     while not os.path.isdir(os.path.join(p, ".hg")):
         oldp, p = p, os.path.dirname(p)
         if p == oldp:
             return None
 
     return p
 
 def bailifchanged(repo):
     if repo.dirstate.p2() != nullid:
         raise util.Abort(_('outstanding uncommitted merge'))
     modified, added, removed, deleted = repo.status()[:4]
     if modified or added or removed or deleted:
         raise util.Abort(_("outstanding uncommitted changes"))
 
 def logmessage(ui, opts):
     """ get the log message according to -m and -l option """
     message = opts.get('message')
     logfile = opts.get('logfile')
 
     if message and logfile:
         raise util.Abort(_('options --message and --logfile are mutually '
                            'exclusive'))
     if not message and logfile:
         try:
             if logfile == '-':
                 message = ui.fin.read()
             else:
                 message = '\n'.join(util.readfile(logfile).splitlines())
         except IOError, inst:
             raise util.Abort(_("can't read commit message '%s': %s") %
                              (logfile, inst.strerror))
     return message
 
 def loglimit(opts):
     """get the log limit according to option -l/--limit"""
     limit = opts.get('limit')
     if limit:
         try:
             limit = int(limit)
         except ValueError:
             raise util.Abort(_('limit must be a positive integer'))
         if limit <= 0:
             raise util.Abort(_('limit must be positive'))
     else:
         limit = None
     return limit
 
 def makefilename(repo, pat, node,
                   total=None, seqno=None, revwidth=None, pathname=None):
     node_expander = {
         'H': lambda: hex(node),
         'R': lambda: str(repo.changelog.rev(node)),
         'h': lambda: short(node),
         }
     expander = {
         '%': lambda: '%',
         'b': lambda: os.path.basename(repo.root),
         }
 
     try:
         if node:
             expander.update(node_expander)
         if node:
             expander['r'] = (lambda:
                     str(repo.changelog.rev(node)).zfill(revwidth or 0))
         if total is not None:
             expander['N'] = lambda: str(total)
         if seqno is not None:
             expander['n'] = lambda: str(seqno)
         if total is not None and seqno is not None:
             expander['n'] = lambda: str(seqno).zfill(len(str(total)))
         if pathname is not None:
             expander['s'] = lambda: os.path.basename(pathname)
             expander['d'] = lambda: os.path.dirname(pathname) or '.'
             expander['p'] = lambda: pathname
 
         newname = []
         patlen = len(pat)
         i = 0
         while i < patlen:
             c = pat[i]
             if c == '%':
                 i += 1
                 c = pat[i]
                 c = expander[c]()
             newname.append(c)
             i += 1
         return ''.join(newname)
     except KeyError, inst:
         raise util.Abort(_("invalid format spec '%%%s' in output filename") %
                          inst.args[0])
 
 def makefileobj(repo, pat, node=None, total=None,
                 seqno=None, revwidth=None, mode='wb', pathname=None):
 
     writable = mode not in ('r', 'rb')
 
     if not pat or pat == '-':
         fp = writable and repo.ui.fout or repo.ui.fin
+        if hasattr(fp, 'fileno'):
         return os.fdopen(os.dup(fp.fileno()), mode)
+        else:
+            # if this fp can't be duped properly, return
+            # a dummy object that can be closed
+            class wrappedfileobj(object):
+                noop = lambda x: None
+                def __init__(self, f):
+                    self.f = f
+                def __getattr__(self, attr):
+                    if attr == 'close':
+                        return self.noop
+                    else:
+                        return getattr(self.f, attr)
+
+            return wrappedfileobj(fp)
     if hasattr(pat, 'write') and writable:
         return pat
     if hasattr(pat, 'read') and 'r' in mode:
         return pat
     return open(makefilename(repo, pat, node, total, seqno, revwidth,
                               pathname),
                 mode)
 
 def openrevlog(repo, cmd, file_, opts):
     """opens the changelog, manifest, a filelog or a given revlog"""
     cl = opts['changelog']
     mf = opts['manifest']
     msg = None
     if cl and mf:
         msg = _('cannot specify --changelog and --manifest at the same time')
     elif cl or mf:
         if file_:
             msg = _('cannot specify filename with --changelog or --manifest')
         elif not repo:
             msg = _('cannot specify --changelog or --manifest '
                     'without a repository')
     if msg:
         raise util.Abort(msg)
 
     r = None
     if repo:
         if cl:
             r = repo.changelog
         elif mf:
             r = repo.manifest
         elif file_:
             filelog = repo.file(file_)
             if len(filelog):
                 r = filelog
     if not r:
         if not file_:
             raise error.CommandError(cmd, _('invalid arguments'))
         if not os.path.isfile(file_):
             raise util.Abort(_("revlog '%s' not found") % file_)
         r = revlog.revlog(scmutil.opener(os.getcwd(), audit=False),
                           file_[:-2] + ".i")
     return r
 
 def copy(ui, repo, pats, opts, rename=False):
     # called with the repo lock held
     #
     # hgsep => pathname that uses "/" to separate directories
     # ossep => pathname that uses os.sep to separate directories
     cwd = repo.getcwd()
     targets = {}
     after = opts.get("after")
     dryrun = opts.get("dry_run")
     wctx = repo[None]
 
     def walkpat(pat):
         srcs = []
         badstates = after and '?' or '?r'
         m = scmutil.match(repo, [pat], opts, globbed=True)
         for abs in repo.walk(m):
             state = repo.dirstate[abs]
             rel = m.rel(abs)
             exact = m.exact(abs)
             if state in badstates:
                 if exact and state == '?':
                     ui.warn(_('%s: not copying - file is not managed\n') % rel)
                 if exact and state == 'r':
                     ui.warn(_('%s: not copying - file has been marked for'
                               ' remove\n') % rel)
                 continue
             # abs: hgsep
             # rel: ossep
             srcs.append((abs, rel, exact))
         return srcs
 
     # abssrc: hgsep
     # relsrc: ossep
     # otarget: ossep
     def copyfile(abssrc, relsrc, otarget, exact):
         abstarget = scmutil.canonpath(repo.root, cwd, otarget)
         reltarget = repo.pathto(abstarget, cwd)
         target = repo.wjoin(abstarget)
         src = repo.wjoin(abssrc)
         state = repo.dirstate[abstarget]
 
         scmutil.checkportable(ui, abstarget)
 
         # check for collisions
         prevsrc = targets.get(abstarget)
         if prevsrc is not None:
             ui.warn(_('%s: not overwriting - %s collides with %s\n') %
                     (reltarget, repo.pathto(abssrc, cwd),
                      repo.pathto(prevsrc, cwd)))
             return
 
         # check for overwrites
         exists = os.path.lexists(target)
         if not after and exists or after and state in 'mn':
             if not opts['force']:
                 ui.warn(_('%s: not overwriting - file exists\n') %
                         reltarget)
                 return
 
         if after:
             if not exists:
                 if rename:
                     ui.warn(_('%s: not recording move - %s does not exist\n') %
                             (relsrc, reltarget))
                 else:
                     ui.warn(_('%s: not recording copy - %s does not exist\n') %
                             (relsrc, reltarget))
                 return
         elif not dryrun:
             try:
                 if exists:
                     os.unlink(target)
                 targetdir = os.path.dirname(target) or '.'
                 if not os.path.isdir(targetdir):
                     os.makedirs(targetdir)
                 util.copyfile(src, target)
                 srcexists = True
             except IOError, inst:
                 if inst.errno == errno.ENOENT:
                     ui.warn(_('%s: deleted in working copy\n') % relsrc)
                     srcexists = False
                 else:
                     ui.warn(_('%s: cannot copy - %s\n') %
                             (relsrc, inst.strerror))
                     return True # report a failure
 
         if ui.verbose or not exact:
             if rename:
                 ui.status(_('moving %s to %s\n') % (relsrc, reltarget))
             else:
                 ui.status(_('copying %s to %s\n') % (relsrc, reltarget))
 
         targets[abstarget] = abssrc
 
         # fix up dirstate
         scmutil.dirstatecopy(ui, repo, wctx, abssrc, abstarget,
                              dryrun=dryrun, cwd=cwd)
         if rename and not dryrun:
             if not after and srcexists:
                 util.unlinkpath(repo.wjoin(abssrc))
             wctx.forget([abssrc])
 
     # pat: ossep
     # dest ossep
     # srcs: list of (hgsep, hgsep, ossep, bool)
     # return: function that takes hgsep and returns ossep
     def targetpathfn(pat, dest, srcs):
         if os.path.isdir(pat):
             abspfx = scmutil.canonpath(repo.root, cwd, pat)
             abspfx = util.localpath(abspfx)
             if destdirexists:
                 striplen = len(os.path.split(abspfx)[0])
             else:
                 striplen = len(abspfx)
             if striplen:
                 striplen += len(os.sep)
             res = lambda p: os.path.join(dest, util.localpath(p)[striplen:])
         elif destdirexists:
             res = lambda p: os.path.join(dest,
                                          os.path.basename(util.localpath(p)))
         else:
             res = lambda p: dest
         return res
 
     # pat: ossep
     # dest ossep
     # srcs: list of (hgsep, hgsep, ossep, bool)
     # return: function that takes hgsep and returns ossep
     def targetpathafterfn(pat, dest, srcs):
         if matchmod.patkind(pat):
             # a mercurial pattern
             res = lambda p: os.path.join(dest,
                                          os.path.basename(util.localpath(p)))
         else:
             abspfx = scmutil.canonpath(repo.root, cwd, pat)
             if len(abspfx) < len(srcs[0][0]):
                 # A directory. Either the target path contains the last
                 # component of the source path or it does not.
                 def evalpath(striplen):
                     score = 0
                     for s in srcs:
                         t = os.path.join(dest, util.localpath(s[0])[striplen:])
                         if os.path.lexists(t):
                             score += 1
                     return score
 
                 abspfx = util.localpath(abspfx)
                 striplen = len(abspfx)
                 if striplen:
                     striplen += len(os.sep)
                 if os.path.isdir(os.path.join(dest, os.path.split(abspfx)[1])):
                     score = evalpath(striplen)
                     striplen1 = len(os.path.split(abspfx)[0])
                     if striplen1:
                         striplen1 += len(os.sep)
                     if evalpath(striplen1) > score:
                         striplen = striplen1
                 res = lambda p: os.path.join(dest,
                                              util.localpath(p)[striplen:])
             else:
                 # a file
                 if destdirexists:
                     res = lambda p: os.path.join(dest,
                                         os.path.basename(util.localpath(p)))
                 else:
                     res = lambda p: dest
         return res
 
 
     pats = scmutil.expandpats(pats)
     if not pats:
         raise util.Abort(_('no source or destination specified'))
     if len(pats) == 1:
         raise util.Abort(_('no destination specified'))
     dest = pats.pop()
     destdirexists = os.path.isdir(dest) and not os.path.islink(dest)
     if not destdirexists:
         if len(pats) > 1 or matchmod.patkind(pats[0]):
             raise util.Abort(_('with multiple sources, destination must be an '
                                'existing directory'))
         if util.endswithsep(dest):
             raise util.Abort(_('destination %s is not a directory') % dest)
 
     tfn = targetpathfn
     if after:
         tfn = targetpathafterfn
     copylist = []
     for pat in pats:
         srcs = walkpat(pat)
         if not srcs:
             continue
         copylist.append((tfn(pat, dest, srcs), srcs))
     if not copylist:
         raise util.Abort(_('no files to copy'))
 
     errors = 0
     for targetpath, srcs in copylist:
         for abssrc, relsrc, exact in srcs:
             if copyfile(abssrc, relsrc, targetpath(abssrc), exact):
                 errors += 1
 
     if errors:
         ui.warn(_('(consider using --after)\n'))
 
     return errors != 0
 
 def service(opts, parentfn=None, initfn=None, runfn=None, logfile=None,
     runargs=None, appendpid=False):
     '''Run a command as a service.'''
 
     if opts['daemon'] and not opts['daemon_pipefds']:
         # Signal child process startup with file removal
         lockfd, lockpath = tempfile.mkstemp(prefix='hg-service-')
         os.close(lockfd)
         try:
             if not runargs:
                 runargs = util.hgcmd() + sys.argv[1:]
             runargs.append('--daemon-pipefds=%s' % lockpath)
             # Don't pass --cwd to the child process, because we've already
             # changed directory.
             for i in xrange(1, len(runargs)):
                 if runargs[i].startswith('--cwd='):
                     del runargs[i]
                     break
                 elif runargs[i].startswith('--cwd'):
                     del runargs[i:i + 2]
                     break
             def condfn():
                 return not os.path.exists(lockpath)
             pid = util.rundetached(runargs, condfn)
             if pid < 0:
                 raise util.Abort(_('child process failed to start'))
         finally:
             try:
                 os.unlink(lockpath)
             except OSError, e:
                 if e.errno != errno.ENOENT:
                     raise
         if parentfn:
             return parentfn(pid)
         else:
             return
 
     if initfn:
         initfn()
 
     if opts['pid_file']:
         mode = appendpid and 'a' or 'w'
         fp = open(opts['pid_file'], mode)
         fp.write(str(os.getpid()) + '\n')
         fp.close()
 
     if opts['daemon_pipefds']:
         lockpath = opts['daemon_pipefds']
         try:
             os.setsid()
         except AttributeError:
             pass
         os.unlink(lockpath)
         util.hidewindow()
         sys.stdout.flush()
         sys.stderr.flush()
 
         nullfd = os.open(util.nulldev, os.O_RDWR)
         logfilefd = nullfd
         if logfile:
             logfilefd = os.open(logfile, os.O_RDWR | os.O_CREAT | os.O_APPEND)
         os.dup2(nullfd, 0)
         os.dup2(logfilefd, 1)
         os.dup2(logfilefd, 2)
         if nullfd not in (0, 1, 2):
             os.close(nullfd)
         if logfile and logfilefd not in (0, 1, 2):
             os.close(logfilefd)
 
     if runfn:
         return runfn()
 
 def export(repo, revs, template='hg-%h.patch', fp=None, switch_parent=False,
            opts=None):
     '''export changesets as hg patches.'''
 
     total = len(revs)
     revwidth = max([len(str(rev)) for rev in revs])
 
     def single(rev, seqno, fp):
         ctx = repo[rev]
         node = ctx.node()
         parents = [p.node() for p in ctx.parents() if p]
         branch = ctx.branch()
         if switch_parent:
             parents.reverse()
         prev = (parents and parents[0]) or nullid
 
         shouldclose = False
         if not fp:
             fp = makefileobj(repo, template, node, total=total, seqno=seqno,
                              revwidth=revwidth, mode='ab')
             if fp != template:
                 shouldclose = True
         if fp != sys.stdout and hasattr(fp, 'name'):
             repo.ui.note("%s\n" % fp.name)
 
         fp.write("# HG changeset patch\n")
         fp.write("# User %s\n" % ctx.user())
         fp.write("# Date %d %d\n" % ctx.date())
         if branch and branch != 'default':
             fp.write("# Branch %s\n" % branch)
         fp.write("# Node ID %s\n" % hex(node))
         fp.write("# Parent  %s\n" % hex(prev))
         if len(parents) > 1:
             fp.write("# Parent  %s\n" % hex(parents[1]))
         fp.write(ctx.description().rstrip())
         fp.write("\n\n")
 
         for chunk in patch.diff(repo, prev, node, opts=opts):
             fp.write(chunk)
 
         if shouldclose:
             fp.close()
 
     for seqno, rev in enumerate(revs):
         single(rev, seqno + 1, fp)
 
 def diffordiffstat(ui, repo, diffopts, node1, node2, match,
                    changes=None, stat=False, fp=None, prefix='',
                    listsubrepos=False):
     '''show diff or diffstat.'''
     if fp is None:
         write = ui.write
     else:
         def write(s, **kw):
             fp.write(s)
 
     if stat:
         diffopts = diffopts.copy(context=0)
         width = 80
         if not ui.plain():
             width = ui.termwidth()
         chunks = patch.diff(repo, node1, node2, match, changes, diffopts,
                             prefix=prefix)
         for chunk, label in patch.diffstatui(util.iterlines(chunks),
                                              width=width,
                                              git=diffopts.git):
             write(chunk, label=label)
     else:
         for chunk, label in patch.diffui(repo, node1, node2, match,
                                          changes, diffopts, prefix=prefix):
             write(chunk, label=label)
 
     if listsubrepos:
         ctx1 = repo[node1]
         ctx2 = repo[node2]
         for subpath, sub in subrepo.itersubrepos(ctx1, ctx2):
             if node2 is not None:
                 node2 = ctx2.substate[subpath][1]
             submatch = matchmod.narrowmatcher(subpath, match)
             sub.diff(diffopts, node2, submatch, changes=changes,
                      stat=stat, fp=fp, prefix=prefix)
 
 class changeset_printer(object):
     '''show changeset information when templating not requested.'''
 
     def __init__(self, ui, repo, patch, diffopts, buffered):
         self.ui = ui
         self.repo = repo
         self.buffered = buffered
         self.patch = patch
         self.diffopts = diffopts
         self.header = {}
         self.hunk = {}
         self.lastheader = None
         self.footer = None
 
     def flush(self, rev):
         if rev in self.header:
             h = self.header[rev]
             if h != self.lastheader:
                 self.lastheader = h
                 self.ui.write(h)
             del self.header[rev]
         if rev in self.hunk:
             self.ui.write(self.hunk[rev])
             del self.hunk[rev]
             return 1
         return 0
 
     def close(self):
         if self.footer:
             self.ui.write(self.footer)
 
     def show(self, ctx, copies=None, matchfn=None, **props):
         if self.buffered:
             self.ui.pushbuffer()
             self._show(ctx, copies, matchfn, props)
             self.hunk[ctx.rev()] = self.ui.popbuffer(labeled=True)
         else:
             self._show(ctx, copies, matchfn, props)
 
     def _show(self, ctx, copies, matchfn, props):
         '''show a single changeset or file revision'''
         changenode = ctx.node()
         rev = ctx.rev()
 
         if self.ui.quiet:
             self.ui.write("%d:%s\n" % (rev, short(changenode)),
                           label='log.node')
             return
 
         log = self.repo.changelog
         date = util.datestr(ctx.date())
 
         hexfunc = self.ui.debugflag and hex or short
 
         parents = [(p, hexfunc(log.node(p)))
                    for p in self._meaningful_parentrevs(log, rev)]
 
         self.ui.write(_("changeset:   %d:%s\n") % (rev, hexfunc(changenode)),
                       label='log.changeset')
 
         branch = ctx.branch()
         # don't show the default branch name
         if branch != 'default':
             self.ui.write(_("branch:      %s\n") % branch,
                           label='log.branch')
         for bookmark in self.repo.nodebookmarks(changenode):
             self.ui.write(_("bookmark:    %s\n") % bookmark,
                     label='log.bookmark')
         for tag in self.repo.nodetags(changenode):
             self.ui.write(_("tag:         %s\n") % tag,
                           label='log.tag')
         for parent in parents:
             self.ui.write(_("parent:      %d:%s\n") % parent,
                           label='log.parent')
 
         if self.ui.debugflag:
             mnode = ctx.manifestnode()
             self.ui.write(_("manifest:    %d:%s\n") %
                           (self.repo.manifest.rev(mnode), hex(mnode)),
                           label='ui.debug log.manifest')
         self.ui.write(_("user:        %s\n") % ctx.user(),
                       label='log.user')
         self.ui.write(_("date:        %s\n") % date,
                       label='log.date')
 
         if self.ui.debugflag:
             files = self.repo.status(log.parents(changenode)[0], changenode)[:3]
             for key, value in zip([_("files:"), _("files+:"), _("files-:")],
                                   files):
                 if value:
                     self.ui.write("%-12s %s\n" % (key, " ".join(value)),
                                   label='ui.debug log.files')
         elif ctx.files() and self.ui.verbose:
             self.ui.write(_("files:       %s\n") % " ".join(ctx.files()),
                           label='ui.note log.files')
         if copies and self.ui.verbose:
             copies = ['%s (%s)' % c for c in copies]
             self.ui.write(_("copies:      %s\n") % ' '.join(copies),
                           label='ui.note log.copies')
 
         extra = ctx.extra()
         if extra and self.ui.debugflag:
             for key, value in sorted(extra.items()):
                 self.ui.write(_("extra:       %s=%s\n")
                               % (key, value.encode('string_escape')),
                               label='ui.debug log.extra')
 
         description = ctx.description().strip()
         if description:
             if self.ui.verbose:
                 self.ui.write(_("description:\n"),
                               label='ui.note log.description')
                 self.ui.write(description,
                               label='ui.note log.description')
                 self.ui.write("\n\n")
             else:
                 self.ui.write(_("summary:     %s\n") %
                               description.splitlines()[0],
                               label='log.summary')
         self.ui.write("\n")
 
         self.showpatch(changenode, matchfn)
 
     def showpatch(self, node, matchfn):
         if not matchfn:
             matchfn = self.patch
         if matchfn:
             stat = self.diffopts.get('stat')
             diff = self.diffopts.get('patch')
             diffopts = patch.diffopts(self.ui, self.diffopts)
             prev = self.repo.changelog.parents(node)[0]
             if stat:
                 diffordiffstat(self.ui, self.repo, diffopts, prev, node,
                                match=matchfn, stat=True)
             if diff:
                 if stat:
                     self.ui.write("\n")
                 diffordiffstat(self.ui, self.repo, diffopts, prev, node,
                                match=matchfn, stat=False)
             self.ui.write("\n")
 
     def _meaningful_parentrevs(self, log, rev):
         """Return list of meaningful (or all if debug) parentrevs for rev.
 
         For merges (two non-nullrev revisions) both parents are meaningful.
         Otherwise the first parent revision is considered meaningful if it
         is not the preceding revision.
         """
         parents = log.parentrevs(rev)
         if not self.ui.debugflag and parents[1] == nullrev:
             if parents[0] >= rev - 1:
                 parents = []
             else:
                 parents = [parents[0]]
         return parents
 
 
 class changeset_templater(changeset_printer):
     '''format changeset information.'''
 
     def __init__(self, ui, repo, patch, diffopts, mapfile, buffered):
         changeset_printer.__init__(self, ui, repo, patch, diffopts, buffered)
         formatnode = ui.debugflag and (lambda x: x) or (lambda x: x[:12])
         defaulttempl = {
             'parent': '{rev}:{node|formatnode} ',
             'manifest': '{rev}:{node|formatnode}',
             'file_copy': '{name} ({source})',
             'extra': '{key}={value|stringescape}'
             }
         # filecopy is preserved for compatibility reasons
         defaulttempl['filecopy'] = defaulttempl['file_copy']
         self.t = templater.templater(mapfile, {'formatnode': formatnode},
                                      cache=defaulttempl)
         self.cache = {}
 
     def use_template(self, t):
         '''set template string to use'''
         self.t.cache['changeset'] = t
 
     def _meaningful_parentrevs(self, ctx):
         """Return list of meaningful (or all if debug) parentrevs for rev.
         """
         parents = ctx.parents()
         if len(parents) > 1:
             return parents
         if self.ui.debugflag:
             return [parents[0], self.repo['null']]
         if parents[0].rev() >= ctx.rev() - 1:
             return []
         return parents
 
     def _show(self, ctx, copies, matchfn, props):
         '''show a single changeset or file revision'''
 
         showlist = templatekw.showlist
 
         # showparents() behaviour depends on ui trace level which
         # causes unexpected behaviours at templating level and makes
         # it harder to extract it in a standalone function. Its
         # behaviour cannot be changed so leave it here for now.
         def showparents(**args):
             ctx = args['ctx']
             parents = [[('rev', p.rev()), ('node', p.hex())]
                        for p in self._meaningful_parentrevs(ctx)]
             return showlist('parent', parents, **args)
 
         props = props.copy()
         props.update(templatekw.keywords)
         props['parents'] = showparents
         props['templ'] = self.t
         props['ctx'] = ctx
         props['repo'] = self.repo
         props['revcache'] = {'copies': copies}
         props['cache'] = self.cache
 
         # find correct templates for current mode
 
         tmplmodes = [
             (True, None),
             (self.ui.verbose, 'verbose'),
             (self.ui.quiet, 'quiet'),
             (self.ui.debugflag, 'debug'),
         ]
 
         types = {'header': '', 'footer':'', 'changeset': 'changeset'}
         for mode, postfix  in tmplmodes:
             for type in types:
                 cur = postfix and ('%s_%s' % (type, postfix)) or type
                 if mode and cur in self.t:
                     types[type] = cur
 
         try:
 
             # write header
             if types['header']:
                 h = templater.stringify(self.t(types['header'], **props))
                 if self.buffered:
                     self.header[ctx.rev()] = h
                 else:
                     if self.lastheader != h:
                         self.lastheader = h
                         self.ui.write(h)
 
             # write changeset metadata, then patch if requested
             key = types['changeset']
             self.ui.write(templater.stringify(self.t(key, **props)))
             self.showpatch(ctx.node(), matchfn)
 
             if types['footer']:
                 if not self.footer:
                     self.footer = templater.stringify(self.t(types['footer'],
                                                       **props))
 
         except KeyError, inst:
             msg = _("%s: no key named '%s'")
             raise util.Abort(msg % (self.t.mapfile, inst.args[0]))
         except SyntaxError, inst:
             raise util.Abort('%s: %s' % (self.t.mapfile, inst.args[0]))
 
 def show_changeset(ui, repo, opts, buffered=False):
     """show one changeset using template or regular display.
 
     Display format will be the first non-empty hit of:
     1. option 'template'
     2. option 'style'
     3. [ui] setting 'logtemplate'
     4. [ui] setting 'style'
     If all of these values are either the unset or the empty string,
     regular display via changeset_printer() is done.
     """
     # options
     patch = False
     if opts.get('patch') or opts.get('stat'):
         patch = scmutil.matchall(repo)
 
     tmpl = opts.get('template')
     style = None
     if tmpl:
         tmpl = templater.parsestring(tmpl, quoted=False)
     else:
         style = opts.get('style')
 
     # ui settings
     if not (tmpl or style):
         tmpl = ui.config('ui', 'logtemplate')
         if tmpl:
             tmpl = templater.parsestring(tmpl)
         else:
             style = util.expandpath(ui.config('ui', 'style', ''))
 
     if not (tmpl or style):
         return changeset_printer(ui, repo, patch, opts, buffered)
 
     mapfile = None
     if style and not tmpl:
         mapfile = style
         if not os.path.split(mapfile)[0]:
             mapname = (templater.templatepath('map-cmdline.' + mapfile)
                        or templater.templatepath(mapfile))
             if mapname:
                 mapfile = mapname
 
     try:
         t = changeset_templater(ui, repo, patch, opts, mapfile, buffered)
     except SyntaxError, inst:
         raise util.Abort(inst.args[0])
     if tmpl:
         t.use_template(tmpl)
     return t
 
 def finddate(ui, repo, date):
     """Find the tipmost changeset that matches the given date spec"""
 
     df = util.matchdate(date)
     m = scmutil.matchall(repo)
     results = {}
 
     def prep(ctx, fns):
         d = ctx.date()
         if df(d[0]):
             results[ctx.rev()] = d
 
     for ctx in walkchangerevs(repo, m, {'rev': None}, prep):
         rev = ctx.rev()
         if rev in results:
             ui.status(_("Found revision %s from %s\n") %
                       (rev, util.datestr(results[rev])))
             return str(rev)
 
     raise util.Abort(_("revision matching date not found"))
 
 def walkchangerevs(repo, match, opts, prepare):
     '''Iterate over files and the revs in which they changed.
 
     Callers most commonly need to iterate backwards over the history
     in which they are interested. Doing so has awful (quadratic-looking)
     performance, so we use iterators in a "windowed" way.
 
     We walk a window of revisions in the desired order.  Within the
     window, we first walk forwards to gather data, then in the desired
     order (usually backwards) to display it.
 
     This function returns an iterator yielding contexts. Before
     yielding each context, the iterator will first call the prepare
     function on each context in the window in forward order.'''
 
     def increasing_windows(start, end, windowsize=8, sizelimit=512):
         if start < end:
             while start < end:
                 yield start, min(windowsize, end - start)
                 start += windowsize
                 if windowsize < sizelimit:
                     windowsize *= 2
         else:
             while start > end:
                 yield start, min(windowsize, start - end - 1)
                 start -= windowsize
                 if windowsize < sizelimit:
                     windowsize *= 2
 
     follow = opts.get('follow') or opts.get('follow_first')
 
     if not len(repo):
         return []
 
     if follow:
         defrange = '%s:0' % repo['.'].rev()
     else:
         defrange = '-1:0'
     revs = scmutil.revrange(repo, opts['rev'] or [defrange])
     if not revs:
         return []
     wanted = set()
     slowpath = match.anypats() or (match.files() and opts.get('removed'))
     fncache = {}
     change = util.cachefunc(repo.changectx)
 
     # First step is to fill wanted, the set of revisions that we want to yield.
     # When it does not induce extra cost, we also fill fncache for revisions in
     # wanted: a cache of filenames that were changed (ctx.files()) and that
     # match the file filtering conditions.
 
     if not slowpath and not match.files():
         # No files, no patterns.  Display all revs.
         wanted = set(revs)
     copies = []
 
     if not slowpath:
         # We only have to read through the filelog to find wanted revisions
 
         minrev, maxrev = min(revs), max(revs)
         def filerevgen(filelog, last):
             """
             Only files, no patterns.  Check the history of each file.
 
             Examines filelog entries within minrev, maxrev linkrev range
             Returns an iterator yielding (linkrev, parentlinkrevs, copied)
             tuples in backwards order
             """
             cl_count = len(repo)
             revs = []
             for j in xrange(0, last + 1):
                 linkrev = filelog.linkrev(j)
                 if linkrev < minrev:
                     continue
                 # only yield rev for which we have the changelog, it can
                 # happen while doing "hg log" during a pull or commit
                 if linkrev >= cl_count:
                     break
 
                 parentlinkrevs = []
                 for p in filelog.parentrevs(j):
                     if p != nullrev:
                         parentlinkrevs.append(filelog.linkrev(p))
                 n = filelog.node(j)
                 revs.append((linkrev, parentlinkrevs,
                              follow and filelog.renamed(n)))
 
             return reversed(revs)
         def iterfiles():
             for filename in match.files():
                 yield filename, None
             for filename_node in copies:
                 yield filename_node
         for file_, node in iterfiles():
             filelog = repo.file(file_)
             if not len(filelog):
                 if node is None:
                     # A zero count may be a directory or deleted file, so
                     # try to find matching entries on the slow path.
                     if follow:
                         raise util.Abort(
                             _('cannot follow nonexistent file: "%s"') % file_)
                     slowpath = True
                     break
                 else:
                     continue
 
             if node is None:
                 last = len(filelog) - 1
             else:
                 last = filelog.rev(node)
 
 
             # keep track of all ancestors of the file
             ancestors = set([filelog.linkrev(last)])
 
             # iterate from latest to oldest revision
             for rev, flparentlinkrevs, copied in filerevgen(filelog, last):
                 if not follow:
                     if rev > maxrev:
                         continue
                 else:
                     # Note that last might not be the first interesting
                     # rev to us:
                     # if the file has been changed after maxrev, we'll
                     # have linkrev(last) > maxrev, and we still need
                     # to explore the file graph
                     if rev not in ancestors:
                         continue
                     # XXX insert 1327 fix here
                     if flparentlinkrevs:
                         ancestors.update(flparentlinkrevs)
 
                 fncache.setdefault(rev, []).append(file_)
                 wanted.add(rev)
                 if copied:
                     copies.append(copied)
     if slowpath:
         # We have to read the changelog to match filenames against
         # changed files
 
         if follow:
             raise util.Abort(_('can only follow copies/renames for explicit '
                                'filenames'))
 
         # The slow path checks files modified in every changeset.
         for i in sorted(revs):
             ctx = change(i)
             matches = filter(match, ctx.files())
             if matches:
                 fncache[i] = matches
                 wanted.add(i)
 
     class followfilter(object):
         def __init__(self, onlyfirst=False):
             self.startrev = nullrev
             self.roots = set()
             self.onlyfirst = onlyfirst
 
         def match(self, rev):
             def realparents(rev):
                 if self.onlyfirst:
                     return repo.changelog.parentrevs(rev)[0:1]
                 else:
                     return filter(lambda x: x != nullrev,
                                   repo.changelog.parentrevs(rev))
 
             if self.startrev == nullrev:
                 self.startrev = rev
                 return True
 
             if rev > self.startrev:
                 # forward: all descendants
                 if not self.roots:
                     self.roots.add(self.startrev)
                 for parent in realparents(rev):
                     if parent in self.roots:
                         self.roots.add(rev)
                         return True
             else:
                 # backwards: all parents
                 if not self.roots:
                     self.roots.update(realparents(self.startrev))
                 if rev in self.roots:
                     self.roots.remove(rev)
                     self.roots.update(realparents(rev))
                     return True
 
             return False
 
     # it might be worthwhile to do this in the iterator if the rev range
     # is descending and the prune args are all within that range
     for rev in opts.get('prune', ()):
         rev = repo.changelog.rev(repo.lookup(rev))
         ff = followfilter()
         stop = min(revs[0], revs[-1])
         for x in xrange(rev, stop - 1, -1):
             if ff.match(x):
                 wanted.discard(x)
 
     # Now that wanted is correctly initialized, we can iterate over the
     # revision range, yielding only revisions in wanted.
     def iterate():
         if follow and not match.files():
             ff = followfilter(onlyfirst=opts.get('follow_first'))
             def want(rev):
                 return ff.match(rev) and rev in wanted
         else:
             def want(rev):
                 return rev in wanted
 
         for i, window in increasing_windows(0, len(revs)):
             nrevs = [rev for rev in revs[i:i + window] if want(rev)]
             for rev in sorted(nrevs):
                 fns = fncache.get(rev)
                 ctx = change(rev)
                 if not fns:
                     def fns_generator():
                         for f in ctx.files():
                             if match(f):
                                 yield f
                     fns = fns_generator()
                 prepare(ctx, fns)
             for rev in nrevs:
                 yield change(rev)
     return iterate()
 
 def add(ui, repo, match, dryrun, listsubrepos, prefix):
     join = lambda f: os.path.join(prefix, f)
     bad = []
     oldbad = match.bad
     match.bad = lambda x, y: bad.append(x) or oldbad(x, y)
     names = []
     wctx = repo[None]
     cca = None
     abort, warn = scmutil.checkportabilityalert(ui)
     if abort or warn:
         cca = scmutil.casecollisionauditor(ui, abort, wctx)
     for f in repo.walk(match):
         exact = match.exact(f)
         if exact or f not in repo.dirstate:
             if cca:
                 cca(f)
             names.append(f)
             if ui.verbose or not exact:
                 ui.status(_('adding %s\n') % match.rel(join(f)))
 
     if listsubrepos:
         for subpath in wctx.substate:
             sub = wctx.sub(subpath)
             try:
                 submatch = matchmod.narrowmatcher(subpath, match)
                 bad.extend(sub.add(ui, submatch, dryrun, prefix))
             except error.LookupError:
                 ui.status(_("skipping missing subrepository: %s\n")
                                % join(subpath))
 
     if not dryrun:
         rejected = wctx.add(names, prefix)
         bad.extend(f for f in rejected if f in match.files())
     return bad
 
 def commit(ui, repo, commitfunc, pats, opts):
     '''commit the specified files or all outstanding changes'''
     date = opts.get('date')
     if date:
         opts['date'] = util.parsedate(date)
     message = logmessage(ui, opts)
 
     # extract addremove carefully -- this function can be called from a command
     # that doesn't support addremove
     if opts.get('addremove'):
         scmutil.addremove(repo, pats, opts)
 
     return commitfunc(ui, repo, message, scmutil.match(repo, pats, opts), opts)
 
 def commiteditor(repo, ctx, subs):
     if ctx.description():
         return ctx.description()
     return commitforceeditor(repo, ctx, subs)
 
 def commitforceeditor(repo, ctx, subs):
     edittext = []
     modified, added, removed = ctx.modified(), ctx.added(), ctx.removed()
     if ctx.description():
         edittext.append(ctx.description())
     edittext.append("")
     edittext.append("") # Empty line between message and comments.
     edittext.append(_("HG: Enter commit message."
                       "  Lines beginning with 'HG:' are removed."))
     edittext.append(_("HG: Leave message empty to abort commit."))
     edittext.append("HG: --")
     edittext.append(_("HG: user: %s") % ctx.user())
     if ctx.p2():
         edittext.append(_("HG: branch merge"))
     if ctx.branch():
         edittext.append(_("HG: branch '%s'") % ctx.branch())
     edittext.extend([_("HG: subrepo %s") % s for s in subs])
     edittext.extend([_("HG: added %s") % f for f in added])
     edittext.extend([_("HG: changed %s") % f for f in modified])
     edittext.extend([_("HG: removed %s") % f for f in removed])
     if not added and not modified and not removed:
         edittext.append(_("HG: no files changed"))
     edittext.append("")
     # run editor in the repository root
     olddir = os.getcwd()
     os.chdir(repo.root)
     text = repo.ui.edit("\n".join(edittext), ctx.user())
     text = re.sub("(?m)^HG:.*(\n|$)", "", text)
     os.chdir(olddir)
 
     if not text.strip():
         raise util.Abort(_("empty commit message"))
 
     return text
 
 def command(table):
     '''returns a function object bound to table which can be used as
     a decorator for populating table as a command table'''
 
     def cmd(name, options, synopsis=None):
         def decorator(func):
             if synopsis:
                 table[name] = func, options[:], synopsis
             else:
                 table[name] = func, options[:]
             return func
         return decorator
 
     return cmd