mercurial/help.py

dispatch: provide help for disabled extensions and commands

Before a command is declared unknown, each extension in hgext is searched,
starting with hgext.<cmdname>. If there's a matching command, a help message
suggests the appropriate extension and how to enable it.

Every extension could potentially be imported, but for cases like rebase,
relink, etc. only one extension is imported.

For the case of "hg help disabledext", if the extension is in hgext, the
extension description is read and a similar help suggestion is printed.
No extension import occurs.

# 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 sys, os
import extensions


def moduledoc(file):
    '''return the top-level python documentation for the given file

    Loosely inspired by pydoc.source_synopsis(), but rewritten to
    handle triple quotes and to return the whole text instead of just
    the synopsis'''
    result = []

    line = file.readline()
    while line[:1] == '#' or not line.strip():
        line = file.readline()
        if not line:
            break

    start = line[:3]
    if start == '\"\"\"' or start == "\'\'\'":
        line = line[3:]
        while line:
            if line.rstrip().endswith(start):
                line = line.split(start)[0]
                if line:
                    result.append(line)
                break
            elif not line:
                return None # unmatched delimiter
            result.append(line)
            line = file.readline()
    else:
        return None

    return ''.join(result)

def listexts(header, exts, maxlength, indent=1):
    '''return a text listing of the given extensions'''
    if not exts:
        return ''
    result = '\n%s\n\n' % header
    for name, desc in sorted(exts.iteritems()):
        result += '%s%-*s %s\n' % (' ' * indent, maxlength + 2,
                                   ':%s:' % name, desc)
    return result

def extshelp():
    doc = loaddoc('extensions')()

    exts, maxlength = extensions.enabled()
    doc += listexts(_('enabled extensions:'), exts, maxlength)

    exts, maxlength = extensions.disabled()
    doc += listexts(_('disabled extensions:'), exts, maxlength)

    return doc

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

    def loader():
        if hasattr(sys, 'frozen'):
            module = sys.executable
        else:
            module = __file__
        base = os.path.dirname(module)

        for dir in ('.', '..'):
            docdir = os.path.join(base, dir, 'help')
            if os.path.isdir(docdir):
                break

        path = os.path.join(docdir, topic + ".txt")
        return gettext(open(path).read())
    return loader

helptable = (
    (["config"], _("Configuration Files"), loaddoc('config')),
    (["dates"], _("Date Formats"), loaddoc('dates')),
    (["patterns"], _("File Name Patterns"), loaddoc('patterns')),
    (['environment', 'env'], _('Environment Variables'),
     loaddoc('environment')),
    (['revs', 'revisions'], _('Specifying Single Revisions'),
     loaddoc('revisions')),
    (['mrevs', 'multirevs'], _('Specifying Multiple Revisions'),
     loaddoc('multirevs')),
    (['diffs'], _('Diff Formats'), loaddoc('diffs')),
    (['templating', 'templates'], _('Template Usage'),
     loaddoc('templates')),
    (['urls'], _('URL Paths'), loaddoc('urls')),
    (["extensions"], _("Using additional features"), extshelp),
)