annotate mercurial/extensions.py @ 10364:de1e7099d100

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.

# extensions.py - extension handling for 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.

import imp, os
import util, cmdutil, help, error
from i18n import _, gettext

_extensions = {}
_order = []

def extensions():
    for name in _order:
        module = _extensions[name]
        if module:
            yield name, module

def find(name):
    '''return module with given extension name'''
    try:
        return _extensions[name]
    except KeyError:
        for k, v in _extensions.iteritems():
            if k.endswith('.' + name) or k.endswith('/' + name):
                return v
        raise KeyError(name)

def loadpath(path, module_name):
    module_name = module_name.replace('.', '_')
    path = util.expandpath(path)
    if os.path.isdir(path):
        # module/__init__.py style
        d, f = os.path.split(path.rstrip('/'))
        fd, fpath, desc = imp.find_module(f, [d])
        return imp.load_module(module_name, fd, fpath, desc)
    else:
        return imp.load_source(module_name, path)

def load(ui, name, path):
    # unused ui argument kept for backwards compatibility
    if name.startswith('hgext.') or name.startswith('hgext/'):
        shortname = name[6:]
    else:
        shortname = name
    if shortname in _extensions:
        return
    _extensions[shortname] = None
    if path:
        # the module will be loaded in sys.modules
        # choose an unique name so that it doesn't
        # conflicts with other modules
        mod = loadpath(path, 'hgext.%s' % name)
    else:
        def importh(name):
            mod = __import__(name)
            components = name.split('.')
            for comp in components[1:]:
                mod = getattr(mod, comp)
            return mod
        try:
            mod = importh("hgext.%s" % name)
        except ImportError:
            mod = importh(name)
    _extensions[shortname] = mod
    _order.append(shortname)

def loadall(ui):
    result = ui.configitems("extensions")
    newindex = len(_order)
    for (name, path) in result:
        if path:
            if path[0] == '!':
                continue
        try:
            load(ui, name, path)
        except KeyboardInterrupt:
            raise
        except Exception, inst:
            if path:
                ui.warn(_("*** failed to import extension %s from %s: %s\n")
                        % (name, path, inst))
            else:
                ui.warn(_("*** failed to import extension %s: %s\n")
                        % (name, inst))
            if ui.traceback():
                return 1

    for name in _order[newindex:]:
        uisetup = getattr(_extensions[name], 'uisetup', None)
        if uisetup:
            uisetup(ui)

    for name in _order[newindex:]:
        extsetup = getattr(_extensions[name], 'extsetup', None)
        if extsetup:
            try:
                extsetup(ui)
            except TypeError:
                if extsetup.func_code.co_argcount != 0:
                    raise
                extsetup() # old extsetup with no ui argument

def wrapcommand(table, command, wrapper):
    aliases, entry = cmdutil.findcmd(command, table)
    for alias, e in table.iteritems():
        if e is entry:
            key = alias
            break

    origfn = entry[0]
    def wrap(*args, **kwargs):
        return util.checksignature(wrapper)(
            util.checksignature(origfn), *args, **kwargs)

    wrap.__doc__ = getattr(origfn, '__doc__')
    wrap.__module__ = getattr(origfn, '__module__')

    newentry = list(entry)
    newentry[0] = wrap
    table[key] = tuple(newentry)
    return entry

def wrapfunction(container, funcname, wrapper):
    def wrap(*args, **kwargs):
        return wrapper(origfn, *args, **kwargs)

    origfn = getattr(container, funcname)
    setattr(container, funcname, wrap)
    return origfn

def _disabledpaths(strip_init=False):
    '''find paths of disabled extensions. returns a dict of {name: path}
    removes /__init__.py from packages if strip_init is True'''
    import hgext
    extpath = os.path.dirname(os.path.abspath(hgext.__file__))
    try: # might not be a filesystem path
        files = os.listdir(extpath)
    except OSError:
        return {}

    exts = {}
    for e in files:
        if e.endswith('.py'):
            name = e.rsplit('.', 1)[0]
            path = os.path.join(extpath, e)
        else:
            name = e
            path = os.path.join(extpath, e, '__init__.py')
            if not os.path.exists(path):
                continue
            if strip_init:
                path = os.path.dirname(path)
        if name in exts or name in _order or name == '__init__':
            continue
        exts[name] = path
    return exts

def _disabledhelp(path):
    '''retrieve help synopsis of a disabled extension (without importing)'''
    try:
        file = open(path)
    except IOError:
        return
    else:
        doc = help.moduledoc(file)
        file.close()

    if doc: # extracting localized synopsis
        return gettext(doc).splitlines()[0]
    else:
        return _('(no help text available)')

def disabled():
    '''find disabled extensions from hgext
    returns a dict of {name: desc}, and the max name length'''

    paths = _disabledpaths()
    if not paths:
        return None, 0

    exts = {}
    maxlength = 0
    for name, path in paths.iteritems():
        doc = _disabledhelp(path)
        if not doc:
            continue

        exts[name] = doc
        if len(name) > maxlength:
            maxlength = len(name)

    return exts, maxlength

def disabledext(name):
    '''find a specific disabled extension from hgext. returns desc'''
    paths = _disabledpaths()
    if name in paths:
        return _disabledhelp(paths[name])

def disabledcmd(cmd, strict=False):
    '''import disabled extensions until cmd is found.
    returns (cmdname, extname, doc)'''

    paths = _disabledpaths(strip_init=True)
    if not paths:
        raise error.UnknownCommand(cmd)

    def findcmd(cmd, name, path):
        try:
            mod = loadpath(path, 'hgext.%s' % name)
        except Exception:
            return
        try:
            aliases, entry = cmdutil.findcmd(cmd,
                getattr(mod, 'cmdtable', {}), strict)
        except (error.AmbiguousCommand, error.UnknownCommand):
            return
        for c in aliases:
            if c.startswith(cmd):
                cmd = c
                break
        else:
            cmd = aliases[0]
        return (cmd, name, mod)

    # first, search for an extension with the same name as the command
    path = paths.pop(cmd, None)
    if path:
        ext = findcmd(cmd, cmd, path)
        if ext:
            return ext

    # otherwise, interrogate each extension until there's a match
    for name, path in paths.iteritems():
        ext = findcmd(cmd, name, path)
        if ext:
            return ext

    raise error.UnknownCommand(cmd)

def enabled():
    '''return a dict of {name: desc} of extensions, and the max name length'''
    exts = {}
    maxlength = 0
    for ename, ext in extensions():
        doc = (gettext(ext.__doc__) or _('(no help text available)'))
        ename = ename.split('.')[-1]
        maxlength = max(len(ename), maxlength)
        exts[ename] = doc.splitlines()[0].strip()

    return exts, maxlength