view mercurial/help.py @ 25402:0c2ded041d10

exchange: support transferring .hgtags fnodes mapping

On Mozilla's mozilla-beta repository .hgtags fnodes resolution takes
~18s from a clean cache on my machine. This means that the first time
a user runs `hg tags`, `hg log`, or any other command that displays or
accesses tags data, a ~18s pause will occur. There is no output during
this pause. This results in a poor user experience and perception
that Mercurial is slow.

The .hgtags changeset to filenode mapping is deterministic. This
patch takes advantage of that property by implementing support
for transferring .hgtags filenodes mappings in a dedicated bundle2
part. When a client advertising support for the "hgtagsfnodes"
capability requests a bundle, a mapping of changesets to .hgtags
filenodes will be sent to the client.

Only mappings of head changesets included in the bundle will be sent. The
transfer of this mapping effectively eliminates one time tags cache related
pauses after initial clone.

The mappings are sent as binary data. So, 40 bytes per pair of
SHA-1s. On the aforementioned mozilla-beta repository,
659 * 40 = 26,360 raw bytes of mappings are sent over the wire
(in addition to the bundle part headers). Assuming 18s to populate
the cache, we only need to transfer this extra data faster than
1.5 KB/s for overall clone + tags cache population time to be shorter.
Put into perspective, the mozilla-beta repository is ~1 GB in size.
So, this additional data constitutes <0.01% of the cloned data.
The marginal overhead for a multi-second performance win on clones
in my opinion justifies an on-by-default behavior.

# help.py - help data for mercurial
#
# Copyright 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.

from i18n import gettext, _
import itertools, os, textwrap
import error
import extensions, revset, fileset, templatekw, templatefilters, filemerge
import templater
import encoding, util, minirst
import cmdutil
import hgweb.webcommands as webcommands

def listexts(header, exts, indent=1, showdeprecated=False):
    '''return a text listing of the given extensions'''
    rst = []
    if exts:
        rst.append('\n%s\n\n' % header)
        for name, desc in sorted(exts.iteritems()):
            if '(DEPRECATED)' in desc and not showdeprecated:
                continue
            rst.append('%s:%s: %s\n' % (' ' * indent, name, desc))
    return rst

def extshelp():
    rst = loaddoc('extensions')().splitlines(True)
    rst.extend(listexts(
        _('enabled extensions:'), extensions.enabled(), showdeprecated=True))
    rst.extend(listexts(_('disabled extensions:'), extensions.disabled()))
    doc = ''.join(rst)
    return doc

def optrst(header, options, verbose):
    data = []
    multioccur = False
    for option in options:
        if len(option) == 5:
            shortopt, longopt, default, desc, optlabel = option
        else:
            shortopt, longopt, default, desc = option
            optlabel = _("VALUE") # default label

        if not verbose and ("DEPRECATED" in desc or _("DEPRECATED") in desc or
                            "EXPERIMENTAL" in desc or
                            _("EXPERIMENTAL") in desc):
            continue

        so = ''
        if shortopt:
            so = '-' + shortopt
        lo = '--' + longopt
        if default:
            desc += _(" (default: %s)") % default

        if isinstance(default, list):
            lo += " %s [+]" % optlabel
            multioccur = True
        elif (default is not None) and not isinstance(default, bool):
            lo += " %s" % optlabel

        data.append((so, lo, desc))

    if multioccur:
        header += (_(" ([+] can be repeated)"))

    rst = ['\n%s:\n\n' % header]
    rst.extend(minirst.maketable(data, 1))

    return ''.join(rst)

def indicateomitted(rst, omitted, notomitted=None):
    rst.append('\n\n.. container:: omitted\n\n    %s\n\n' % omitted)
    if notomitted:
        rst.append('\n\n.. container:: notomitted\n\n    %s\n\n' % notomitted)

def topicmatch(kw):
    """Return help topics matching kw.

    Returns {'section': [(name, summary), ...], ...} where section is
    one of topics, commands, extensions, or extensioncommands.
    """
    kw = encoding.lower(kw)
    def lowercontains(container):
        return kw in encoding.lower(container)  # translated in helptable
    results = {'topics': [],
               'commands': [],
               'extensions': [],
               'extensioncommands': [],
               }
    for names, header, doc in helptable:
        # Old extensions may use a str as doc.
        if (sum(map(lowercontains, names))
            or lowercontains(header)
            or (callable(doc) and lowercontains(doc()))):
            results['topics'].append((names[0], header))
    import commands # avoid cycle
    for cmd, entry in commands.table.iteritems():
        if len(entry) == 3:
            summary = entry[2]
        else:
            summary = ''
        # translate docs *before* searching there
        docs = _(getattr(entry[0], '__doc__', None)) or ''
        if kw in cmd or lowercontains(summary) or lowercontains(docs):
            doclines = docs.splitlines()
            if doclines:
                summary = doclines[0]
            cmdname = cmd.split('|')[0].lstrip('^')
            results['commands'].append((cmdname, summary))
    for name, docs in itertools.chain(
        extensions.enabled(False).iteritems(),
        extensions.disabled().iteritems()):
        # extensions.load ignores the UI argument
        mod = extensions.load(None, name, '')
        name = name.split('.')[-1]
        if lowercontains(name) or lowercontains(docs):
            # extension docs are already translated
            results['extensions'].append((name, docs.splitlines()[0]))
        for cmd, entry in getattr(mod, 'cmdtable', {}).iteritems():
            if kw in cmd or (len(entry) > 2 and lowercontains(entry[2])):
                cmdname = cmd.split('|')[0].lstrip('^')
                if entry[0].__doc__:
                    cmddoc = gettext(entry[0].__doc__).splitlines()[0]
                else:
                    cmddoc = _('(no help text available)')
                results['extensioncommands'].append((cmdname, cmddoc))
    return results

def loaddoc(topic):
    """Return a delayed loader for help/topic.txt."""

    def loader():
        docdir = os.path.join(util.datapath, 'help')
        path = os.path.join(docdir, topic + ".txt")
        doc = gettext(util.readfile(path))
        for rewriter in helphooks.get(topic, []):
            doc = rewriter(topic, doc)
        return doc

    return loader

helptable = sorted([
    (["config", "hgrc"], _("Configuration Files"), loaddoc('config')),
    (["dates"], _("Date Formats"), loaddoc('dates')),
    (["patterns"], _("File Name Patterns"), loaddoc('patterns')),
    (['environment', 'env'], _('Environment Variables'),
     loaddoc('environment')),
    (['revisions', 'revs'], _('Specifying Single Revisions'),
     loaddoc('revisions')),
    (['multirevs', 'mrevs'], _('Specifying Multiple Revisions'),
     loaddoc('multirevs')),
    (['revsets', 'revset'], _("Specifying Revision Sets"), loaddoc('revsets')),
    (['filesets', 'fileset'], _("Specifying File Sets"), loaddoc('filesets')),
    (['diffs'], _('Diff Formats'), loaddoc('diffs')),
    (['merge-tools', 'mergetools'], _('Merge Tools'), loaddoc('merge-tools')),
    (['templating', 'templates', 'template', 'style'], _('Template Usage'),
     loaddoc('templates')),
    (['urls'], _('URL Paths'), loaddoc('urls')),
    (["extensions"], _("Using Additional Features"), extshelp),
    (["subrepos", "subrepo"], _("Subrepositories"), loaddoc('subrepos')),
    (["hgweb"], _("Configuring hgweb"), loaddoc('hgweb')),
    (["glossary"], _("Glossary"), loaddoc('glossary')),
    (["hgignore", "ignore"], _("Syntax for Mercurial Ignore Files"),
     loaddoc('hgignore')),
    (["phases"], _("Working with Phases"), loaddoc('phases')),
])

# Map topics to lists of callable taking the current topic help and
# returning the updated version
helphooks = {}

def addtopichook(topic, rewriter):
    helphooks.setdefault(topic, []).append(rewriter)

def makeitemsdoc(topic, doc, marker, items, dedent=False):
    """Extract docstring from the items key to function mapping, build a
    .single documentation block and use it to overwrite the marker in doc
    """
    entries = []
    for name in sorted(items):
        text = (items[name].__doc__ or '').rstrip()
        if not text:
            continue
        text = gettext(text)
        if dedent:
            text = textwrap.dedent(text)
        lines = text.splitlines()
        doclines = [(lines[0])]
        for l in lines[1:]:
            # Stop once we find some Python doctest
            if l.strip().startswith('>>>'):
                break
            if dedent:
                doclines.append(l.rstrip())
            else:
                doclines.append('  ' + l.strip())
        entries.append('\n'.join(doclines))
    entries = '\n\n'.join(entries)
    return doc.replace(marker, entries)

def addtopicsymbols(topic, marker, symbols, dedent=False):
    def add(topic, doc):
        return makeitemsdoc(topic, doc, marker, symbols, dedent=dedent)
    addtopichook(topic, add)

addtopicsymbols('filesets', '.. predicatesmarker', fileset.symbols)
addtopicsymbols('merge-tools', '.. internaltoolsmarker',
                filemerge.internalsdoc)
addtopicsymbols('revsets', '.. predicatesmarker', revset.symbols)
addtopicsymbols('templates', '.. keywordsmarker', templatekw.dockeywords)
addtopicsymbols('templates', '.. filtersmarker', templatefilters.filters)
addtopicsymbols('templates', '.. functionsmarker', templater.funcs)
addtopicsymbols('hgweb', '.. webcommandsmarker', webcommands.commands,
                dedent=True)

def help_(ui, name, unknowncmd=False, full=True, **opts):
    '''
    Generate the help for 'name' as unformatted restructured text. If
    'name' is None, describe the commands available.
    '''

    import commands # avoid cycle

    def helpcmd(name):
        try:
            aliases, entry = cmdutil.findcmd(name, commands.table,
                                             strict=unknowncmd)
        except error.AmbiguousCommand, inst:
            # py3k fix: except vars can't be used outside the scope of the
            # except block, nor can be used inside a lambda. python issue4617
            prefix = inst.args[0]
            select = lambda c: c.lstrip('^').startswith(prefix)
            rst = helplist(select)
            return rst

        rst = []

        # check if it's an invalid alias and display its error if it is
        if getattr(entry[0], 'badalias', None):
            rst.append(entry[0].badalias + '\n')
            if entry[0].unknowncmd:
                try:
                    rst.extend(helpextcmd(entry[0].cmdname))
                except error.UnknownCommand:
                    pass
            return rst

        # synopsis
        if len(entry) > 2:
            if entry[2].startswith('hg'):
                rst.append("%s\n" % entry[2])
            else:
                rst.append('hg %s %s\n' % (aliases[0], entry[2]))
        else:
            rst.append('hg %s\n' % aliases[0])
        # aliases
        if full and not ui.quiet and len(aliases) > 1:
            rst.append(_("\naliases: %s\n") % ', '.join(aliases[1:]))
        rst.append('\n')

        # description
        doc = gettext(entry[0].__doc__)
        if not doc:
            doc = _("(no help text available)")
        if util.safehasattr(entry[0], 'definition'):  # aliased command
            if entry[0].definition.startswith('!'):  # shell alias
                doc = _('shell alias for::\n\n    %s') % entry[0].definition[1:]
            else:
                doc = _('alias for: hg %s\n\n%s') % (entry[0].definition, doc)
        doc = doc.splitlines(True)
        if ui.quiet or not full:
            rst.append(doc[0])
        else:
            rst.extend(doc)
        rst.append('\n')

        # check if this command shadows a non-trivial (multi-line)
        # extension help text
        try:
            mod = extensions.find(name)
            doc = gettext(mod.__doc__) or ''
            if '\n' in doc.strip():
                msg = _('(use "hg help -e %s" to show help for '
                        'the %s extension)') % (name, name)
                rst.append('\n%s\n' % msg)
        except KeyError:
            pass

        # options
        if not ui.quiet and entry[1]:
            rst.append(optrst(_("options"), entry[1], ui.verbose))

        if ui.verbose:
            rst.append(optrst(_("global options"),
                              commands.globalopts, ui.verbose))

        if not ui.verbose:
            if not full:
                rst.append(_('\n(use "hg %s -h" to show more help)\n')
                           % name)
            elif not ui.quiet:
                rst.append(_('\n(some details hidden, use --verbose '
                               'to show complete help)'))

        return rst


    def helplist(select=None):
        # list of commands
        if name == "shortlist":
            header = _('basic commands:\n\n')
        elif name == "debug":
            header = _('debug commands (internal and unsupported):\n\n')
        else:
            header = _('list of commands:\n\n')

        h = {}
        cmds = {}
        for c, e in commands.table.iteritems():
            f = c.split("|", 1)[0]
            if select and not select(f):
                continue
            if (not select and name != 'shortlist' and
                e[0].__module__ != commands.__name__):
                continue
            if name == "shortlist" and not f.startswith("^"):
                continue
            f = f.lstrip("^")
            if not ui.debugflag and f.startswith("debug") and name != "debug":
                continue
            doc = e[0].__doc__
            if doc and 'DEPRECATED' in doc and not ui.verbose:
                continue
            doc = gettext(doc)
            if not doc:
                doc = _("(no help text available)")
            h[f] = doc.splitlines()[0].rstrip()
            cmds[f] = c.lstrip("^")

        rst = []
        if not h:
            if not ui.quiet:
                rst.append(_('no commands defined\n'))
            return rst

        if not ui.quiet:
            rst.append(header)
        fns = sorted(h)
        for f in fns:
            if ui.verbose:
                commacmds = cmds[f].replace("|",", ")
                rst.append(" :%s: %s\n" % (commacmds, h[f]))
            else:
                rst.append(' :%s: %s\n' % (f, h[f]))

        if not name:
            exts = listexts(_('enabled extensions:'), extensions.enabled())
            if exts:
                rst.append('\n')
                rst.extend(exts)

            rst.append(_("\nadditional help topics:\n\n"))
            topics = []
            for names, header, doc in helptable:
                topics.append((names[0], header))
            for t, desc in topics:
                rst.append(" :%s: %s\n" % (t, desc))

        if ui.quiet:
            pass
        elif ui.verbose:
            rst.append('\n%s\n' % optrst(_("global options"),
                                         commands.globalopts, ui.verbose))
            if name == 'shortlist':
                rst.append(_('\n(use "hg help" for the full list '
                             'of commands)\n'))
        else:
            if name == 'shortlist':
                rst.append(_('\n(use "hg help" for the full list of commands '
                             'or "hg -v" for details)\n'))
            elif name and not full:
                rst.append(_('\n(use "hg help %s" to show the full help '
                             'text)\n') % name)
            elif name and cmds and name in cmds.keys():
                rst.append(_('\n(use "hg help -v -e %s" to show built-in '
                             'aliases and global options)\n') % name)
            else:
                rst.append(_('\n(use "hg help -v%s" to show built-in aliases '
                             'and global options)\n')
                           % (name and " " + name or ""))
        return rst

    def helptopic(name):
        for names, header, doc in helptable:
            if name in names:
                break
        else:
            raise error.UnknownCommand(name)

        rst = [minirst.section(header)]

        # description
        if not doc:
            rst.append("    %s\n" % _("(no help text available)"))
        if callable(doc):
            rst += ["    %s\n" % l for l in doc().splitlines()]

        if not ui.verbose:
            omitted = _('(some details hidden, use --verbose'
                         ' to show complete help)')
            indicateomitted(rst, omitted)

        try:
            cmdutil.findcmd(name, commands.table)
            rst.append(_('\nuse "hg help -c %s" to see help for '
                       'the %s command\n') % (name, name))
        except error.UnknownCommand:
            pass
        return rst

    def helpext(name):
        try:
            mod = extensions.find(name)
            doc = gettext(mod.__doc__) or _('no help text available')
        except KeyError:
            mod = None
            doc = extensions.disabledext(name)
            if not doc:
                raise error.UnknownCommand(name)

        if '\n' not in doc:
            head, tail = doc, ""
        else:
            head, tail = doc.split('\n', 1)
        rst = [_('%s extension - %s\n\n') % (name.split('.')[-1], head)]
        if tail:
            rst.extend(tail.splitlines(True))
            rst.append('\n')

        if not ui.verbose:
            omitted = _('(some details hidden, use --verbose'
                         ' to show complete help)')
            indicateomitted(rst, omitted)

        if mod:
            try:
                ct = mod.cmdtable
            except AttributeError:
                ct = {}
            modcmds = set([c.split('|', 1)[0] for c in ct])
            rst.extend(helplist(modcmds.__contains__))
        else:
            rst.append(_('(use "hg help extensions" for information on enabling'
                       ' extensions)\n'))
        return rst

    def helpextcmd(name):
        cmd, ext, mod = extensions.disabledcmd(ui, name,
                                               ui.configbool('ui', 'strict'))
        doc = gettext(mod.__doc__).splitlines()[0]

        rst = listexts(_("'%s' is provided by the following "
                              "extension:") % cmd, {ext: doc}, indent=4)
        rst.append('\n')
        rst.append(_('(use "hg help extensions" for information on enabling '
                   'extensions)\n'))
        return rst


    rst = []
    kw = opts.get('keyword')
    if kw:
        matches = topicmatch(kw)
        for t, title in (('topics', _('Topics')),
                         ('commands', _('Commands')),
                         ('extensions', _('Extensions')),
                         ('extensioncommands', _('Extension Commands'))):
            if matches[t]:
                rst.append('%s:\n\n' % title)
                rst.extend(minirst.maketable(sorted(matches[t]), 1))
                rst.append('\n')
        if not rst:
            msg = _('no matches')
            hint = _('try "hg help" for a list of topics')
            raise util.Abort(msg, hint=hint)
    elif name and name != 'shortlist':
        if unknowncmd:
            queries = (helpextcmd,)
        elif opts.get('extension'):
            queries = (helpext,)
        elif opts.get('command'):
            queries = (helpcmd,)
        else:
            queries = (helptopic, helpcmd, helpext, helpextcmd)
        for f in queries:
            try:
                rst = f(name)
                break
            except error.UnknownCommand:
                pass
        else:
            if unknowncmd:
                raise error.UnknownCommand(name)
            else:
                msg = _('no such help topic: %s') % name
                hint = _('try "hg help --keyword %s"') % name
                raise util.Abort(msg, hint=hint)
    else:
        # program name
        if not ui.quiet:
            rst = [_("Mercurial Distributed SCM\n"), '\n']
        rst.extend(helplist())

    return ''.join(rst)