view mercurial/help.py @ 30212:260af19891f2

changegroup: increase write buffer size to 128k

By default, Python defers to the operating system for choosing the
default buffer size on opened files. On my Linux machine, the default
is 4k, which is really small for 2016.

This patch bumps the write buffer size when writing
changegroups/bundles to 128k. This matches the 128k read buffer
we already use on revlogs.

It's worth noting that this only impacts when writing to an explicit
file (such as during `hg bundle`). Buffers when writing to bundle
files via the repo vfs or to a temporary file are not impacted.

When producing a none-v2 bundle file of the mozilla-unified repository,
this change caused the number of write() system calls to drop from
952,449 to 29,788. After this change, the most frequent system
calls are fstat(), read(), lseek(), and open(). There were
2,523,672 system calls after this patch (so a net decrease of
~950k is statistically significant).

This change shows no performance change on my system. But I have a
high-end system with a fast SSD. It is quite possible this change
will have a significant impact on network file systems, where
extra network round trips due to excessive I/O system calls could
introduce significant latency.

# 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 __future__ import absolute_import

import itertools
import os
import textwrap

from .i18n import (
    _,
    gettext,
)
from . import (
    cmdutil,
    encoding,
    error,
    extensions,
    filemerge,
    fileset,
    minirst,
    revset,
    templatefilters,
    templatekw,
    templater,
    util,
)
from .hgweb import (
    webcommands,
)

_exclkeywords = [
    "(DEPRECATED)",
    "(EXPERIMENTAL)",
    # i18n: "(DEPRECATED)" is a keyword, must be translated consistently
    _("(DEPRECATED)"),
    # i18n: "(EXPERIMENTAL)" is a keyword, must be translated consistently
    _("(EXPERIMENTAL)"),
    ]

def listexts(header, exts, indent=1, showdeprecated=False):
    '''return a text listing of the given extensions'''
    rst = []
    if exts:
        for name, desc in sorted(exts.iteritems()):
            if not showdeprecated and any(w in desc for w in _exclkeywords):
                continue
            rst.append('%s:%s: %s\n' % (' ' * indent, name, desc))
    if rst:
        rst.insert(0, '\n%s\n\n' % header)
    return rst

def extshelp(ui):
    rst = loaddoc('extensions')(ui).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 any(w in desc for w in _exclkeywords):
            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 filtercmd(ui, cmd, kw, doc):
    if not ui.debugflag and cmd.startswith("debug") and kw != "debug":
        return True
    if not ui.verbose and doc and any(w in doc for w in _exclkeywords):
        return True
    return False

def topicmatch(ui, 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(ui)))):
            results['topics'].append((names[0], header))
    from . 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.partition('|')[0].lstrip('^')
            if filtercmd(ui, cmdname, kw, docs):
                continue
            results['commands'].append((cmdname, summary))
    for name, docs in itertools.chain(
        extensions.enabled(False).iteritems(),
        extensions.disabled().iteritems()):
        if not docs:
            continue
        mod = extensions.load(ui, name, '')
        name = name.rpartition('.')[-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.partition('|')[0].lstrip('^')
                if entry[0].__doc__:
                    cmddoc = gettext(entry[0].__doc__).splitlines()[0]
                else:
                    cmddoc = _('(no help text available)')
                if filtercmd(ui, cmdname, kw, cmddoc):
                    continue
                results['extensioncommands'].append((cmdname, cmddoc))
    return results

def loaddoc(topic, subdir=None):
    """Return a delayed loader for help/topic.txt."""

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

    return loader

internalstable = sorted([
    (['bundles'], _('Bundles'),
     loaddoc('bundles', subdir='internals')),
    (['changegroups'], _('Changegroups'),
     loaddoc('changegroups', subdir='internals')),
    (['requirements'], _('Repository Requirements'),
     loaddoc('requirements', subdir='internals')),
    (['revlogs'], _('Revision Logs'),
     loaddoc('revlogs', subdir='internals')),
    (['wireprotocol'], _('Wire Protocol'),
     loaddoc('wireprotocol', subdir='internals')),
])

def internalshelp(ui):
    """Generate the index for the "internals" topic."""
    lines = []
    for names, header, doc in internalstable:
        lines.append(' :%s: %s\n' % (names[0], header))

    return ''.join(lines)

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')),
    (['scripting'], _('Using Mercurial from scripts and automation'),
     loaddoc('scripting')),
    (['internals'], _("Technical implementation topics"),
     internalshelp),
])

# Maps topics with sub-topics to a list of their sub-topics.
subtopics = {
    'internals': internalstable,
}

# 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(ui, 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
            or not ui.verbose and any(w in text for w in _exclkeywords)):
            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(ui, topic, doc):
        return makeitemsdoc(ui, 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.keywords)
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, subtopic=None, **opts):
    '''
    Generate the help for 'name' as unformatted restructured text. If
    'name' is None, describe the commands available.
    '''

    from . import commands # avoid cycle

    def helpcmd(name, subtopic=None):
        try:
            aliases, entry = cmdutil.findcmd(name, commands.table,
                                             strict=unknowncmd)
        except error.AmbiguousCommand as 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
            source = entry[0].source
            if entry[0].definition.startswith('!'):  # shell alias
                doc = (_('shell alias for::\n\n    %s\n\ndefined by: %s\n') %
                       (entry[0].definition[1:], source))
            else:
                doc = (_('alias for: hg %s\n\n%s\n\ndefined by: %s\n') %
                       (entry[0].definition, doc, source))
        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, **opts):
        # 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.partition("|")[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("^")
            doc = e[0].__doc__
            if filtercmd(ui, f, name, doc):
                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]))

        ex = opts.get
        anyopts = (ex('keyword') or not (ex('command') or ex('extension')))
        if not name and anyopts:
            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, subtopic=None):
        # Look for sub-topic entry first.
        header, doc = None, None
        if subtopic and name in subtopics:
            for names, header, doc in subtopics[name]:
                if subtopic in names:
                    break

        if not header:
            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(ui).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, subtopic=None):
        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.rpartition('.')[-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.partition('|')[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, subtopic=None):
        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,
                       showdeprecated=True)
        rst.append('\n')
        rst.append(_("(use 'hg help extensions' for information on enabling "
                   "extensions)\n"))
        return rst


    rst = []
    kw = opts.get('keyword')
    if kw or name is None and any(opts[o] for o in opts):
        matches = topicmatch(ui, name or '')
        helpareas = []
        if opts.get('extension'):
            helpareas += [('extensions', _('Extensions'))]
        if opts.get('command'):
            helpareas += [('commands', _('Commands'))]
        if not helpareas:
            helpareas = [('topics', _('Topics')),
                         ('commands', _('Commands')),
                         ('extensions', _('Extensions')),
                         ('extensioncommands', _('Extension Commands'))]
        for t, title in helpareas:
            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 error.Abort(msg, hint=hint)
    elif name and name != 'shortlist':
        queries = []
        if unknowncmd:
            queries += [helpextcmd]
        if opts.get('extension'):
            queries += [helpext]
        if opts.get('command'):
            queries += [helpcmd]
        if not queries:
            queries = (helptopic, helpcmd, helpext, helpextcmd)
        for f in queries:
            try:
                rst = f(name, subtopic)
                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 error.Abort(msg, hint=hint)
    else:
        # program name
        if not ui.quiet:
            rst = [_("Mercurial Distributed SCM\n"), '\n']
        rst.extend(helplist(None, **opts))

    return ''.join(rst)