File: raw_building.py

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# copyright 2003-2013 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of logilab-astng.
#
# logilab-astng is free software: you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by the
# Free Software Foundation, either version 2.1 of the License, or (at your
# option) any later version.
#
# logilab-astng is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
# for more details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with logilab-astng. If not, see <http://www.gnu.org/licenses/>.
"""this module contains a set of functions to create astng trees from scratch
(build_* functions) or from living object (object_build_* functions)
"""

__docformat__ = "restructuredtext en"

import sys
from os.path import abspath
from inspect import (getargspec, isdatadescriptor, isfunction, ismethod,
                     ismethoddescriptor, isclass, isbuiltin)

from logilab.astng.node_classes import CONST_CLS
from logilab.astng.nodes import (Module, Class, Const, const_factory, From,
    Function, EmptyNode, Name, Arguments)
from logilab.astng.bases import BUILTINS, Generator
from logilab.astng.manager import ASTNGManager
MANAGER = ASTNGManager()

_CONSTANTS = tuple(CONST_CLS) # the keys of CONST_CLS eg python builtin types

def _attach_local_node(parent, node, name):
    node.name = name # needed by add_local_node
    parent.add_local_node(node)

_marker = object()

def attach_dummy_node(node, name, object=_marker):
    """create a dummy node and register it in the locals of the given
    node with the specified name
    """
    enode = EmptyNode()
    enode.object = object
    _attach_local_node(node, enode, name)

EmptyNode.has_underlying_object = lambda self: self.object is not _marker

def attach_const_node(node, name, value):
    """create a Const node and register it in the locals of the given
    node with the specified name
    """
    if not name in node.special_attributes:
        _attach_local_node(node, const_factory(value), name)

def attach_import_node(node, modname, membername):
    """create a From node and register it in the locals of the given
    node with the specified name
    """
    from_node = From(modname, [(membername, None)])
    _attach_local_node(node, from_node, membername)


def build_module(name, doc=None):
    """create and initialize a astng Module node"""
    node = Module(name, doc, pure_python=False)
    node.package = False
    node.parent = None
    return node

def build_class(name, basenames=(), doc=None):
    """create and initialize a astng Class node"""
    node = Class(name, doc)
    for base in basenames:
        basenode = Name()
        basenode.name = base
        node.bases.append(basenode)
        basenode.parent = node
    return node

def build_function(name, args=None, defaults=None, flag=0, doc=None):
    """create and initialize a astng Function node"""
    args, defaults = args or [], defaults or []
    # first argument is now a list of decorators
    func = Function(name, doc)
    func.args = argsnode = Arguments()
    argsnode.args = []
    for arg in args:
        argsnode.args.append(Name())
        argsnode.args[-1].name = arg
        argsnode.args[-1].parent = argsnode
    argsnode.defaults = []
    for default in defaults:
        argsnode.defaults.append(const_factory(default))
        argsnode.defaults[-1].parent = argsnode
    argsnode.kwarg = None
    argsnode.vararg = None
    argsnode.parent = func
    if args:
        register_arguments(func)
    return func


def build_from_import(fromname, names):
    """create and initialize an astng From import statement"""
    return From(fromname, [(name, None) for name in names])

def register_arguments(func, args=None):
    """add given arguments to local

    args is a list that may contains nested lists
    (i.e. def func(a, (b, c, d)): ...)
    """
    if args is None:
        args = func.args.args
        if func.args.vararg:
            func.set_local(func.args.vararg, func.args)
        if func.args.kwarg:
            func.set_local(func.args.kwarg, func.args)
    for arg in args:
        if isinstance(arg, Name):
            func.set_local(arg.name, arg)
        else:
            register_arguments(func, arg.elts)

def object_build_class(node, member, localname):
    """create astng for a living class object"""
    basenames = [base.__name__ for base in member.__bases__]
    return _base_class_object_build(node, member, basenames,
                                    localname=localname)

def object_build_function(node, member, localname):
    """create astng for a living function object"""
    args, varargs, varkw, defaults = getargspec(member)
    if varargs is not None:
        args.append(varargs)
    if varkw is not None:
        args.append(varkw)
    func = build_function(getattr(member, '__name__', None) or localname, args,
                          defaults, member.func_code.co_flags, member.__doc__)
    node.add_local_node(func, localname)

def object_build_datadescriptor(node, member, name):
    """create astng for a living data descriptor object"""
    return _base_class_object_build(node, member, [], name)

def object_build_methoddescriptor(node, member, localname):
    """create astng for a living method descriptor object"""
    # FIXME get arguments ?
    func = build_function(getattr(member, '__name__', None) or localname,
                          doc=member.__doc__)
    # set node's arguments to None to notice that we have no information, not
    # and empty argument list
    func.args.args = None
    node.add_local_node(func, localname)

def _base_class_object_build(node, member, basenames, name=None, localname=None):
    """create astng for a living class object, with a given set of base names
    (e.g. ancestors)
    """
    klass = build_class(name or getattr(member, '__name__', None) or localname,
                        basenames, member.__doc__)
    klass._newstyle = isinstance(member, type)
    node.add_local_node(klass, localname)
    try:
        # limit the instantiation trick since it's too dangerous
        # (such as infinite test execution...)
        # this at least resolves common case such as Exception.args,
        # OSError.errno
        if issubclass(member, Exception):
            instdict = member().__dict__
        else:
            raise TypeError
    except:
        pass
    else:
        for name, obj in instdict.items():
            valnode = EmptyNode()
            valnode.object = obj
            valnode.parent = klass
            valnode.lineno = 1
            klass.instance_attrs[name] = [valnode]
    return klass




class InspectBuilder(object):
    """class for building nodes from living object

    this is actually a really minimal representation, including only Module,
    Function and Class nodes and some others as guessed.
    """

    # astng from living objects ###############################################

    def __init__(self):
        self._done = {}
        self._module = None

    def inspect_build(self, module, modname=None, path=None):
        """build astng from a living module (i.e. using inspect)
        this is used when there is no python source code available (either
        because it's a built-in module or because the .py is not available)
        """
        self._module = module
        if modname is None:
            modname = module.__name__
        try:
            node = build_module(modname, module.__doc__)
        except AttributeError:
            # in jython, java modules have no __doc__ (see #109562)
            node = build_module(modname)
        node.file = node.path = path and abspath(path) or path
        MANAGER.astng_cache[modname] = node
        node.package = hasattr(module, '__path__')
        self._done = {}
        self.object_build(node, module)
        return node

    def object_build(self, node, obj):
        """recursive method which create a partial ast from real objects
         (only function, class, and method are handled)
        """
        if obj in self._done:
            return self._done[obj]
        self._done[obj] = node
        for name in dir(obj):
            try:
                member = getattr(obj, name)
            except AttributeError:
                # damned ExtensionClass.Base, I know you're there !
                attach_dummy_node(node, name)
                continue
            if ismethod(member):
                member = member.im_func
            if isfunction(member):
                # verify this is not an imported function
                filename = getattr(member.func_code, 'co_filename', None)
                if filename is None:
                    assert isinstance(member, object)
                    object_build_methoddescriptor(node, member, name)
                elif filename != getattr(self._module, '__file__', None):
                    attach_dummy_node(node, name, member)
                else:
                    object_build_function(node, member, name)
            elif isbuiltin(member):
                if self.imported_member(node, member, name):
                    #if obj is object:
                    #    print 'skippp', obj, name, member
                    continue
                object_build_methoddescriptor(node, member, name)
            elif isclass(member):
                if self.imported_member(node, member, name):
                    continue
                if member in self._done:
                    class_node = self._done[member]
                    if not class_node in node.locals.get(name, ()):
                        node.add_local_node(class_node, name)
                else:
                    class_node = object_build_class(node, member, name)
                    # recursion
                    self.object_build(class_node, member)
                if name == '__class__' and class_node.parent is None:
                    class_node.parent = self._done[self._module]
            elif ismethoddescriptor(member):
                assert isinstance(member, object)
                object_build_methoddescriptor(node, member, name)
            elif isdatadescriptor(member):
                assert isinstance(member, object)
                object_build_datadescriptor(node, member, name)
            elif type(member) in _CONSTANTS:
                attach_const_node(node, name, member)
            else:
                # create an empty node so that the name is actually defined
                attach_dummy_node(node, name, member)

    def imported_member(self, node, member, name):
        """verify this is not an imported class or handle it"""
        # /!\ some classes like ExtensionClass doesn't have a __module__
        # attribute ! Also, this may trigger an exception on badly built module
        # (see http://www.logilab.org/ticket/57299 for instance)
        try:
            modname = getattr(member, '__module__', None)
        except:
            # XXX use logging
            print 'unexpected error while building astng from living object'
            import traceback
            traceback.print_exc()
            modname = None
        if modname is None:
            if name in ('__new__', '__subclasshook__'):
                # Python 2.5.1 (r251:54863, Sep  1 2010, 22:03:14)
                # >>> print object.__new__.__module__
                # None
                modname = BUILTINS
            else:
                attach_dummy_node(node, name, member)
                return True
        if {'gtk': 'gtk._gtk'}.get(modname, modname) != self._module.__name__:
            # check if it sounds valid and then add an import node, else use a
            # dummy node
            try:
                getattr(sys.modules[modname], name)
            except (KeyError, AttributeError):
                attach_dummy_node(node, name, member)
            else:
                attach_import_node(node, modname, name)
            return True
        return False


### astng boot strapping ################################################### ###
ASTNG_BUILDER = InspectBuilder()

_CONST_PROXY = {}
def astng_boot_strapping():
    """astng boot strapping the builtins module"""
    # this boot strapping is necessary since we need the Const nodes to
    # inspect_build builtins, and then we can proxy Const
    from logilab.common.compat import builtins
    astng_builtin = ASTNG_BUILDER.inspect_build(builtins)
    for cls, node_cls in CONST_CLS.items():
        if cls is type(None):
            proxy = build_class('NoneType')
            proxy.parent = astng_builtin
        else:
            proxy = astng_builtin.getattr(cls.__name__)[0]
        if cls in (dict, list, set, tuple):
            node_cls._proxied = proxy
        else:
            _CONST_PROXY[cls] = proxy

astng_boot_strapping()

# TODO : find a nicer way to handle this situation;
# However __proxied introduced an
# infinite recursion (see https://bugs.launchpad.net/pylint/+bug/456870)
def _set_proxied(const):
    return _CONST_PROXY[const.value.__class__]
Const._proxied = property(_set_proxied)

from types import GeneratorType
Generator._proxied = Class(GeneratorType.__name__, GeneratorType.__doc__)
ASTNG_BUILDER.object_build(Generator._proxied, GeneratorType)