# extensions.py - extension handling for mercurial

#

# Copyright 2005-2007 Matt Mackall <mpm@selenic.com>

#

# 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 imp

import os

from .i18n import (

    _,

    gettext,

)

from . import (

    cmdutil,

    error,

    util,

)

_extensions = {}

_aftercallbacks = {}

_order = []

_builtin = set(['hbisect', 'bookmarks', 'parentrevspec', 'progress', 'interhg',

                'inotify'])

def extensions(ui=None):

    if ui:

        def enabled(name):

            for format in ['%s', 'hgext.%s']:

                conf = ui.config('extensions', format % name)

                if conf is not None and not conf.startswith('!'):

                    return True

    else:

        enabled = lambda name: True

    for name in _order:

        module = _extensions[name]

        if module and enabled(name):

            yield name, module

def find(name):

    '''return module with given extension name'''

    mod = None

    try:

        mod =  _extensions[name]

    except KeyError:

        for k, v in _extensions.iteritems():

            if k.endswith('.' + name) or k.endswith('/' + name):

                mod = v

                break

    if not mod:

        raise KeyError(name)

    return mod

def loadpath(path, module_name):

    module_name = module_name.replace('.', '_')

    path = util.normpath(util.expandpath(path))

    if os.path.isdir(path):

        # module/__init__.py style

        d, f = os.path.split(path)

        fd, fpath, desc = imp.find_module(f, [d])

        return imp.load_module(module_name, fd, fpath, desc)

    else:

        try:

            return imp.load_source(module_name, path)

        except IOError as exc:

            if not exc.filename:

                exc.filename = path # python does not fill this

            raise

def load(ui, name, path):

    if name.startswith('hgext.') or name.startswith('hgext/'):

        shortname = name[6:]

    else:

        shortname = name

    if shortname in _builtin:

        return None

    if shortname in _extensions:

        return _extensions[shortname]

    _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 as err:

            ui.debug('could not import hgext.%s (%s): trying %s\n'

                     % (name, err, name))

            if ui.debugflag:

                ui.traceback()

            mod = importh(name)

    # Before we do anything with the extension, check against minimum stated

    # compatibility. This gives extension authors a mechanism to have their

    # extensions short circuit when loaded with a known incompatible version

    # of Mercurial.

    minver = getattr(mod, 'minimumhgversion', None)

    if minver and util.versiontuple(minver, 2) > util.versiontuple(n=2):

        ui.warn(_('(third party extension %s requires version %s or newer '

                  'of Mercurial; disabling)\n') % (shortname, minver))

        return

    _extensions[shortname] = mod

    _order.append(shortname)

    for fn in _aftercallbacks.get(shortname, []):

        fn(loaded=True)

    return mod

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 as 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))

            ui.traceback()

    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

    # Call aftercallbacks that were never met.

    for shortname in _aftercallbacks:

        if shortname in _extensions:

            continue

        for fn in _aftercallbacks[shortname]:

            fn(loaded=False)

    # loadall() is called multiple times and lingering _aftercallbacks

    # entries could result in double execution. See issue4646.

    _aftercallbacks.clear()

def afterloaded(extension, callback):

    '''Run the specified function after a named extension is loaded.

    If the named extension is already loaded, the callback will be called

    immediately.

    If the named extension never loads, the callback will be called after

    all extensions have been loaded.

    The callback receives the named argument ``loaded``, which is a boolean

    indicating whether the dependent extension actually loaded.

    '''

    if extension in _extensions:

        callback(loaded=True)

    else:

        _aftercallbacks.setdefault(extension, []).append(callback)

def bind(func, *args):

    '''Partial function application

      Returns a new function that is the partial application of args and kwargs

      to func.  For example,

          f(1, 2, bar=3) === bind(f, 1)(2, bar=3)'''

    assert callable(func)

    def closure(*a, **kw):

        return func(*(args + a), **kw)

    return closure

def wrapcommand(table, command, wrapper, synopsis=None, docstring=None):

    '''Wrap the command named `command' in table

    Replace command in the command table with wrapper. The wrapped command will

    be inserted into the command table specified by the table argument.

    The wrapper will be called like

      wrapper(orig, *args, **kwargs)

    where orig is the original (wrapped) function, and *args, **kwargs

    are the arguments passed to it.

    Optionally append to the command synopsis and docstring, used for help.

    For example, if your extension wraps the ``bookmarks`` command to add the

    flags ``--remote`` and ``--all`` you might call this function like so:

      synopsis = ' [-a] [--remote]'

      docstring = """

      The ``remotenames`` extension adds the ``--remote`` and ``--all`` (``-a``)

      flags to the bookmarks command. Either flag will show the remote bookmarks

      known to the repository; ``--remote`` will also suppress the output of the

      local bookmarks.

      """

      extensions.wrapcommand(commands.table, 'bookmarks', exbookmarks,

                             synopsis, docstring)

    '''

    assert callable(wrapper)

    aliases, entry = cmdutil.findcmd(command, table)

    for alias, e in table.iteritems():

        if e is entry:

            key = alias

            break

    origfn = entry[0]

    wrap = bind(util.checksignature(wrapper), util.checksignature(origfn))

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

    doc = getattr(origfn, '__doc__')

    if docstring is not None:

        doc += docstring

    wrap.__doc__ = doc

    newentry = list(entry)

    newentry[0] = wrap

    if synopsis is not None:

        newentry[2] += synopsis

    table[key] = tuple(newentry)

    return entry

def wrapfunction(container, funcname, wrapper):

    '''Wrap the function named funcname in container

    Replace the funcname member in the given container with the specified

    wrapper. The container is typically a module, class, or instance.

    The wrapper will be called like

      wrapper(orig, *args, **kwargs)

    where orig is the original (wrapped) function, and *args, **kwargs

    are the arguments passed to it.

    Wrapping methods of the repository object is not recommended since

    it conflicts with extensions that extend the repository by

    subclassing. All extensions that need to extend methods of

    localrepository should use this subclassing trick: namely,

    reposetup() should look like

      def reposetup(ui, repo):

          class myrepo(repo.__class__):

              def whatever(self, *args, **kwargs):

                  [...extension stuff...]

                  super(myrepo, self).whatever(*args, **kwargs)

                  [...extension stuff...]

          repo.__class__ = myrepo

    In general, combining wrapfunction() with subclassing does not

    work. Since you cannot control what other extensions are loaded by

    your end users, you should play nicely with others by using the

    subclass trick.

    '''

    assert callable(wrapper)

    origfn = getattr(container, funcname)

    assert callable(origfn)

    setattr(container, funcname, bind(wrapper, origfn))

    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 _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 _disabledhelp(path):

    '''retrieve help synopsis of a disabled extension (without importing)'''

    try:

        file = open(path)

    except IOError:

        return

    else:

        doc = _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}'''

    try:

        from hgext import __index__

        return dict((name, gettext(desc))

                    for name, desc in __index__.docs.iteritems()

                    if name not in _order)

    except (ImportError, AttributeError):

        pass

    paths = _disabledpaths()

    if not paths:

        return {}

    exts = {}

    for name, path in paths.iteritems():

        doc = _disabledhelp(path)

        if doc:

            exts[name] = doc

    return exts

def disabledext(name):

    '''find a specific disabled extension from hgext. returns desc'''

    try:

        from hgext import __index__

        if name in _order:  # enabled

            return

        else:

            return gettext(__index__.docs.get(name))