doc/gendoc.py

emitrevision: consider ancestors revision to emit as available base

This should make more delta base valid. This notably affects:

* case where we skipped some parent with empty delta to directly delta against
  an ancestors
* case where an intermediate snapshots is stored.

This change means we could sent largish intermediate snapshots over the wire.
However this is actually a sub goal here. Sending snapshots over the wire means
the client have a high odd of simply storing the pre-computed delta instead of
doing a lengthy process that will… end up doing the same intermediate snapshot.

In addition the overall size of snapshot (or any level) is "only" some or the
overall delta size. (0.17% for my mercurial clone, 20% for my clone of Mozilla
try). So Sending them other the wire is unlikely to change large impact on the
bandwidth used.

If we decide that minimising the bandwidth is an explicit goal, we should
introduce new logic to filter-out snapshot as delta. The current code has no
notion explicite of snapshot so far, they just tended to fall into the wobbly
filtering options.

In some cases, this patch can yield large improvement to the bundling time:

    ### data-env-vars.name      = mozilla-try-2019-02-18-zstd-sparse-revlog
      # benchmark.name          = perf-bundle
      # benchmark.variants.revs = last-100000
    before: 68.787066 seconds
    after:  47.552677 seconds (-30.87%)

That translate to large improvement to the pull time :

    ### data-env-vars.name           = mozilla-try-2019-02-18-zstd-sparse-revlog
      # benchmark.name               = pull
      # benchmark.variants.issue6528 = disabled
      # benchmark.variants.revs      = last-100000
    before: 142.186625 seconds
    after:   75.897745 seconds  (-46.62%)

No significant negative impact have been observed.

#!/usr/bin/env python3
"""usage: %s DOC ...

where DOC is the name of a document
"""


import os
import sys
import textwrap

try:
    import msvcrt

    msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
    msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY)
except ImportError:
    pass

# This script is executed during installs and may not have C extensions
# available. Relax C module requirements.
os.environ['HGMODULEPOLICY'] = 'allow'
# import from the live mercurial repo
sys.path.insert(0, os.path.abspath(".."))
from mercurial import demandimport

demandimport.enable()

from mercurial import (
    commands,
    encoding,
    extensions,
    fancyopts,
    help,
    minirst,
    pycompat,
    ui as uimod,
)
from mercurial.i18n import (
    gettext,
    _,
)
from mercurial.utils import stringutil

table = commands.table
globalopts = commands.globalopts
helptable = help.helptable
loaddoc = help.loaddoc


def get_desc(docstr):
    if not docstr:
        return b"", b""
    # sanitize
    docstr = docstr.strip(b"\n")
    docstr = docstr.rstrip()
    shortdesc = docstr.splitlines()[0].strip()

    i = docstr.find(b"\n")
    if i != -1:
        desc = docstr[i + 2 :]
    else:
        desc = shortdesc

    desc = textwrap.dedent(desc.decode('latin1')).encode('latin1')

    return (shortdesc, desc)


def get_opts(opts):
    for opt in opts:
        if len(opt) == 5:
            shortopt, longopt, default, desc, optlabel = opt
        else:
            shortopt, longopt, default, desc = opt
            optlabel = _(b"VALUE")
        allopts = []
        if shortopt:
            allopts.append(b"-%s" % shortopt)
        if longopt:
            allopts.append(b"--%s" % longopt)
        if isinstance(default, list):
            allopts[-1] += b" <%s[+]>" % optlabel
        elif (default is not None) and not isinstance(default, bool):
            allopts[-1] += b" <%s>" % optlabel
        if b'\n' in desc:
            # only remove line breaks and indentation
            desc = b' '.join(l.lstrip() for l in desc.split(b'\n'))
        if isinstance(default, fancyopts.customopt):
            default = default.getdefaultvalue()
        if default:
            default = stringutil.forcebytestr(default)
            desc += _(b" (default: %s)") % default
        yield (b", ".join(allopts), desc)


def get_cmd(cmd, cmdtable):
    d = {}
    attr = cmdtable[cmd]
    cmds = cmd.lstrip(b"^").split(b"|")

    d[b'cmd'] = cmds[0]
    d[b'aliases'] = cmd.split(b"|")[1:]
    d[b'desc'] = get_desc(gettext(pycompat.getdoc(attr[0])))
    d[b'opts'] = list(get_opts(attr[1]))

    s = b'hg ' + cmds[0]
    if len(attr) > 2:
        if not attr[2].startswith(b'hg'):
            s += b' ' + attr[2]
        else:
            s = attr[2]
    d[b'synopsis'] = s.strip()

    return d


def showdoc(ui):
    # print options
    ui.write(minirst.section(_(b"Options")))
    multioccur = False
    for optstr, desc in get_opts(globalopts):
        ui.write(b"%s\n    %s\n\n" % (optstr, desc))
        if optstr.endswith(b"[+]>"):
            multioccur = True
    if multioccur:
        ui.write(_(b"\n[+] marked option can be specified multiple times\n"))
        ui.write(b"\n")

    # print cmds
    ui.write(minirst.section(_(b"Commands")))
    commandprinter(ui, table, minirst.subsection, minirst.subsubsection)

    # print help topics
    # The config help topic is included in the hgrc.5 man page.
    helpprinter(ui, helptable, minirst.section, exclude=[b'config'])

    ui.write(minirst.section(_(b"Extensions")))
    ui.write(
        _(
            b"This section contains help for extensions that are "
            b"distributed together with Mercurial. Help for other "
            b"extensions is available in the help system."
        )
    )
    ui.write(
        (
            b"\n\n"
            b".. contents::\n"
            b"   :class: htmlonly\n"
            b"   :local:\n"
            b"   :depth: 1\n\n"
        )
    )

    for extensionname in sorted(allextensionnames()):
        mod = extensions.load(ui, extensionname, None)
        ui.write(minirst.subsection(extensionname))
        ui.write(b"%s\n\n" % gettext(pycompat.getdoc(mod)))
        cmdtable = getattr(mod, 'cmdtable', None)
        if cmdtable:
            ui.write(minirst.subsubsection(_(b'Commands')))
            commandprinter(
                ui,
                cmdtable,
                minirst.subsubsubsection,
                minirst.subsubsubsubsection,
            )


def showtopic(ui, topic):
    extrahelptable = [
        ([b"common"], b'', loaddoc(b'common'), help.TOPIC_CATEGORY_MISC),
        ([b"hg.1"], b'', loaddoc(b'hg.1'), help.TOPIC_CATEGORY_CONFIG),
        ([b"hg-ssh.8"], b'', loaddoc(b'hg-ssh.8'), help.TOPIC_CATEGORY_CONFIG),
        (
            [b"hgignore.5"],
            b'',
            loaddoc(b'hgignore.5'),
            help.TOPIC_CATEGORY_CONFIG,
        ),
        ([b"hgrc.5"], b'', loaddoc(b'hgrc.5'), help.TOPIC_CATEGORY_CONFIG),
        (
            [b"hgignore.5.gendoc"],
            b'',
            loaddoc(b'hgignore'),
            help.TOPIC_CATEGORY_CONFIG,
        ),
        (
            [b"hgrc.5.gendoc"],
            b'',
            loaddoc(b'config'),
            help.TOPIC_CATEGORY_CONFIG,
        ),
    ]
    helpprinter(ui, helptable + extrahelptable, None, include=[topic])


def helpprinter(ui, helptable, sectionfunc, include=[], exclude=[]):
    for h in helptable:
        names, sec, doc = h[0:3]
        if exclude and names[0] in exclude:
            continue
        if include and names[0] not in include:
            continue
        for name in names:
            ui.write(b".. _%s:\n" % name)
        ui.write(b"\n")
        if sectionfunc:
            ui.write(sectionfunc(sec))
        if callable(doc):
            doc = doc(ui)
        ui.write(doc)
        ui.write(b"\n")


def commandprinter(ui, cmdtable, sectionfunc, subsectionfunc):
    """Render restructuredtext describing a list of commands and their
    documentations, grouped by command category.

    Args:
      ui: UI object to write the output to
      cmdtable: a dict that maps a string of the command name plus its aliases
        (separated with pipes) to a 3-tuple of (the command's function, a list
        of its option descriptions, and a string summarizing available
        options). Example, with aliases added for demonstration purposes:

          'phase|alias1|alias2': (
             <function phase at 0x7f0816b05e60>,
             [ ('p', 'public', False, 'set changeset phase to public'),
               ...,
               ('r', 'rev', [], 'target revision', 'REV')],
             '[-p|-d|-s] [-f] [-r] [REV...]'
          )
      sectionfunc: minirst function to format command category headers
      subsectionfunc: minirst function to format command headers
    """
    h = {}
    for c, attr in cmdtable.items():
        f = c.split(b"|")[0]
        f = f.lstrip(b"^")
        h[f] = c
    cmds = h.keys()

    def helpcategory(cmd):
        """Given a canonical command name from `cmds` (above), retrieve its
        help category. If helpcategory is None, default to CATEGORY_NONE.
        """
        fullname = h[cmd]
        details = cmdtable[fullname]
        helpcategory = details[0].helpcategory
        return helpcategory or help.registrar.command.CATEGORY_NONE

    cmdsbycategory = {category: [] for category in help.CATEGORY_ORDER}
    for cmd in cmds:
        # If a command category wasn't registered, the command won't get
        # rendered below, so we raise an AssertionError.
        if helpcategory(cmd) not in cmdsbycategory:
            raise AssertionError(
                "The following command did not register its (category) in "
                "help.CATEGORY_ORDER: %s (%s)" % (cmd, helpcategory(cmd))
            )
        cmdsbycategory[helpcategory(cmd)].append(cmd)

    # Print the help for each command. We present the commands grouped by
    # category, and we use help.CATEGORY_ORDER as a guide for a helpful order
    # in which to present the categories.
    for category in help.CATEGORY_ORDER:
        categorycmds = cmdsbycategory[category]
        if not categorycmds:
            # Skip empty categories
            continue
        # Print a section header for the category.
        # For now, the category header is at the same level as the headers for
        # the commands in the category; this is fixed in the next commit.
        ui.write(sectionfunc(help.CATEGORY_NAMES[category]))
        # Print each command in the category
        for f in sorted(categorycmds):
            if f.startswith(b"debug"):
                continue
            d = get_cmd(h[f], cmdtable)
            ui.write(subsectionfunc(d[b'cmd']))
            # short description
            ui.write(d[b'desc'][0])
            # synopsis
            ui.write(b"::\n\n")
            synopsislines = d[b'synopsis'].splitlines()
            for line in synopsislines:
                # some commands (such as rebase) have a multi-line
                # synopsis
                ui.write(b"   %s\n" % line)
            ui.write(b'\n')
            # description
            ui.write(b"%s\n\n" % d[b'desc'][1])
            # options
            opt_output = list(d[b'opts'])
            if opt_output:
                opts_len = max([len(line[0]) for line in opt_output])
                ui.write(_(b"Options:\n\n"))
                multioccur = False
                for optstr, desc in opt_output:
                    if desc:
                        s = b"%-*s  %s" % (opts_len, optstr, desc)
                    else:
                        s = optstr
                    ui.write(b"%s\n" % s)
                    if optstr.endswith(b"[+]>"):
                        multioccur = True
                if multioccur:
                    ui.write(
                        _(
                            b"\n[+] marked option can be specified"
                            b" multiple times\n"
                        )
                    )
                ui.write(b"\n")
            # aliases
            if d[b'aliases']:
                # Note the empty comment, this is required to separate this
                # (which should be a blockquote) from any preceding things (such
                # as a definition list).
                ui.write(
                    _(b"..\n\n    aliases: %s\n\n") % b" ".join(d[b'aliases'])
                )


def allextensionnames():
    return set(extensions.enabled().keys()) | set(extensions.disabled().keys())


if __name__ == "__main__":
    doc = b'hg.1.gendoc'
    if len(sys.argv) > 1:
        doc = encoding.strtolocal(sys.argv[1])

    ui = uimod.ui.load()
    # Trigger extensions to load. This is disabled by default because it uses
    # the current user's configuration, which is often not what is wanted.
    if encoding.environ.get(b'GENDOC_LOAD_CONFIGURED_EXTENSIONS', b'0') != b'0':
        extensions.loadall(ui)

    if doc == b'hg.1.gendoc':
        showdoc(ui)
    else:
        showtopic(ui, encoding.strtolocal(sys.argv[1]))