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# Copyright (c) 2006-2011, 2013-2014 LOGILAB S.A. (Paris, FRANCE) <contact@logilab.fr>
# Copyright (c) 2014-2016 Claudiu Popa <pcmanticore@gmail.com>
# Copyright (c) 2014 Google, Inc.
# Copyright (c) 2015-2016 Cara Vinson <ceridwenv@gmail.com>
# Licensed under the LGPL: https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html
# For details: https://github.com/PyCQA/astroid/blob/master/COPYING.LESSER
"""astroid manager: avoid multiple astroid build of a same module when
possible by providing a class responsible to get astroid representation
from various source and using a cache of built modules)
"""
import os
import sys
import zipimport
import six
from astroid import exceptions
from astroid.interpreter._import import spec
from astroid import modutils
from astroid import transforms
from astroid import util
builder = util.lazy_import('builder')
def safe_repr(obj):
try:
return repr(obj)
except Exception: # pylint: disable=broad-except
return '???'
class AstroidManager(object):
"""the astroid manager, responsible to build astroid from files
or modules.
Use the Borg pattern.
"""
name = 'astroid loader'
brain = {}
def __init__(self):
self.__dict__ = AstroidManager.brain
if not self.__dict__:
# NOTE: cache entries are added by the [re]builder
self.astroid_cache = {}
self._mod_file_cache = {}
self._failed_import_hooks = []
self.always_load_extensions = False
self.extension_package_whitelist = set()
self._transform = transforms.TransformVisitor()
# Export these APIs for convenience
self.register_transform = self._transform.register_transform
self.unregister_transform = self._transform.unregister_transform
def visit_transforms(self, node):
"""Visit the transforms and apply them to the given *node*."""
return self._transform.visit(node)
def ast_from_file(self, filepath, modname=None, fallback=True, source=False):
"""given a module name, return the astroid object"""
try:
filepath = modutils.get_source_file(filepath, include_no_ext=True)
source = True
except modutils.NoSourceFile:
pass
if modname is None:
try:
modname = '.'.join(modutils.modpath_from_file(filepath))
except ImportError:
modname = filepath
if modname in self.astroid_cache and self.astroid_cache[modname].source_file == filepath:
return self.astroid_cache[modname]
if source:
return builder.AstroidBuilder(self).file_build(filepath, modname)
elif fallback and modname:
return self.ast_from_module_name(modname)
raise exceptions.AstroidBuildingError(
'Unable to build an AST for {path}.', path=filepath)
def _build_stub_module(self, modname):
return builder.AstroidBuilder(self).string_build('', modname)
def _build_namespace_module(self, modname, path):
from astroid.builder import build_namespace_package_module
return build_namespace_package_module(modname, path)
def _can_load_extension(self, modname):
if self.always_load_extensions:
return True
if modutils.is_standard_module(modname):
return True
parts = modname.split('.')
return any(
'.'.join(parts[:x]) in self.extension_package_whitelist
for x in range(1, len(parts) + 1))
def ast_from_module_name(self, modname, context_file=None):
"""given a module name, return the astroid object"""
if modname in self.astroid_cache:
return self.astroid_cache[modname]
if modname == '__main__':
return self._build_stub_module(modname)
old_cwd = os.getcwd()
if context_file:
os.chdir(os.path.dirname(context_file))
try:
found_spec = self.file_from_module_name(modname, context_file)
if found_spec.type == spec.ModuleType.PY_ZIPMODULE:
module = self.zip_import_data(found_spec.location)
if module is not None:
return module
elif found_spec.type in (spec.ModuleType.C_BUILTIN,
spec.ModuleType.C_EXTENSION):
if (found_spec.type == spec.ModuleType.C_EXTENSION
and not self._can_load_extension(modname)):
return self._build_stub_module(modname)
try:
module = modutils.load_module_from_name(modname)
except Exception as ex: # pylint: disable=broad-except
util.reraise(exceptions.AstroidImportError(
'Loading {modname} failed with:\n{error}',
modname=modname, path=spec.location, error=ex))
return self.ast_from_module(module, modname)
elif found_spec.type == spec.ModuleType.PY_COMPILED:
raise exceptions.AstroidImportError(
"Unable to load compiled module {modname}.",
modname=modname, path=found_spec.location)
elif found_spec.type == spec.ModuleType.PY_NAMESPACE:
return self._build_namespace_module(modname,
found_spec.submodule_search_locations)
if found_spec.location is None:
raise exceptions.AstroidImportError(
"Can't find a file for module {modname}.",
modname=modname)
return self.ast_from_file(found_spec.location, modname, fallback=False)
except exceptions.AstroidBuildingError as e:
for hook in self._failed_import_hooks:
try:
return hook(modname)
except exceptions.AstroidBuildingError:
pass
raise e
finally:
os.chdir(old_cwd)
def zip_import_data(self, filepath):
if zipimport is None:
return None
astroid_builder = builder.AstroidBuilder(self)
for ext in ('.zip', '.egg'):
try:
eggpath, resource = filepath.rsplit(ext + os.path.sep, 1)
except ValueError:
continue
try:
importer = zipimport.zipimporter(eggpath + ext)
zmodname = resource.replace(os.path.sep, '.')
if importer.is_package(resource):
zmodname = zmodname + '.__init__'
module = astroid_builder.string_build(importer.get_source(resource),
zmodname, filepath)
return module
except Exception: # pylint: disable=broad-except
continue
return None
def file_from_module_name(self, modname, contextfile):
try:
value = self._mod_file_cache[(modname, contextfile)]
traceback = sys.exc_info()[2]
except KeyError:
try:
value = modutils.file_info_from_modpath(
modname.split('.'), context_file=contextfile)
traceback = sys.exc_info()[2]
except ImportError as ex:
value = exceptions.AstroidImportError(
'Failed to import module {modname} with error:\n{error}.',
modname=modname, error=ex)
traceback = sys.exc_info()[2]
self._mod_file_cache[(modname, contextfile)] = value
if isinstance(value, exceptions.AstroidBuildingError):
six.reraise(exceptions.AstroidBuildingError,
value, traceback)
return value
def ast_from_module(self, module, modname=None):
"""given an imported module, return the astroid object"""
modname = modname or module.__name__
if modname in self.astroid_cache:
return self.astroid_cache[modname]
try:
# some builtin modules don't have __file__ attribute
filepath = module.__file__
if modutils.is_python_source(filepath):
return self.ast_from_file(filepath, modname)
except AttributeError:
pass
mock_ast = builder.AstroidBuilder(self).module_build(module, modname)
self.astroid_cache[modname] = mock_ast
return mock_ast
def builtins(self):
"""Get the builtins module
This module is special since it's always built.
"""
return self.astroid_cache[six.moves.builtins.__name__]
def register_failed_import_hook(self, hook):
"""Registers a hook to resolve imports that cannot be found otherwise.
`hook` must be a function that accepts a single argument `modname` which
contains the name of the module or package that could not be imported.
If `hook` can resolve the import, must return a node of type `astroid.Module`,
otherwise, it must raise `AstroidBuildingError`.
"""
self._failed_import_hooks.append(hook)
def cache_module(self, module):
"""Cache a module if no module with the same name is known yet."""
self.astroid_cache.setdefault(module.name, module)
def clear_cache(self):
self.astroid_cache.clear()
from astroid import raw_building
self.astroid_cache[six.moves.builtins.__name__] = raw_building.ast_from_builtins()
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