901 lines
29 KiB
Python
901 lines
29 KiB
Python
"""Core implementation of import.
|
|
|
|
This module is NOT meant to be directly imported! It has been designed such
|
|
that it can be bootstrapped into Python as the implementation of import. As
|
|
such it requires the injection of specific modules and attributes in order to
|
|
work. One should use importlib as the public-facing version of this module.
|
|
|
|
"""
|
|
|
|
# Injected modules are '_warnings', 'imp', 'sys', 'marshal', 'errno', '_io',
|
|
# and '_os' (a.k.a. 'posix', 'nt' or 'os2').
|
|
# Injected attribute is path_sep.
|
|
#
|
|
# When editing this code be aware that code executed at import time CANNOT
|
|
# reference any injected objects! This includes not only global code but also
|
|
# anything specified at the class level.
|
|
|
|
|
|
# Bootstrap-related code ######################################################
|
|
|
|
# XXX Could also expose Modules/getpath.c:joinpath()
|
|
def _path_join(*args):
|
|
"""Replacement for os.path.join."""
|
|
return path_sep.join(x[:-len(path_sep)] if x.endswith(path_sep) else x
|
|
for x in args if x)
|
|
|
|
|
|
def _path_exists(path):
|
|
"""Replacement for os.path.exists."""
|
|
try:
|
|
_os.stat(path)
|
|
except OSError:
|
|
return False
|
|
else:
|
|
return True
|
|
|
|
|
|
def _path_is_mode_type(path, mode):
|
|
"""Test whether the path is the specified mode type."""
|
|
try:
|
|
stat_info = _os.stat(path)
|
|
except OSError:
|
|
return False
|
|
return (stat_info.st_mode & 0o170000) == mode
|
|
|
|
|
|
# XXX Could also expose Modules/getpath.c:isfile()
|
|
def _path_isfile(path):
|
|
"""Replacement for os.path.isfile."""
|
|
return _path_is_mode_type(path, 0o100000)
|
|
|
|
|
|
# XXX Could also expose Modules/getpath.c:isdir()
|
|
def _path_isdir(path):
|
|
"""Replacement for os.path.isdir."""
|
|
if not path:
|
|
path = _os.getcwd()
|
|
return _path_is_mode_type(path, 0o040000)
|
|
|
|
|
|
def _path_without_ext(path, ext_type):
|
|
"""Replacement for os.path.splitext()[0]."""
|
|
for suffix in _suffix_list(ext_type):
|
|
if path.endswith(suffix):
|
|
return path[:-len(suffix)]
|
|
else:
|
|
raise ValueError("path is not of the specified type")
|
|
|
|
|
|
def _path_absolute(path):
|
|
"""Replacement for os.path.abspath."""
|
|
if not path:
|
|
path = _os.getcwd()
|
|
try:
|
|
return _os._getfullpathname(path)
|
|
except AttributeError:
|
|
if path.startswith('/'):
|
|
return path
|
|
else:
|
|
return _path_join(_os.getcwd(), path)
|
|
|
|
|
|
class _closing:
|
|
|
|
"""Simple replacement for contextlib.closing."""
|
|
|
|
def __init__(self, obj):
|
|
self.obj = obj
|
|
|
|
def __enter__(self):
|
|
return self.obj
|
|
|
|
def __exit__(self, *args):
|
|
self.obj.close()
|
|
|
|
|
|
def _wrap(new, old):
|
|
"""Simple substitute for functools.wraps."""
|
|
for replace in ['__module__', '__name__', '__doc__']:
|
|
setattr(new, replace, getattr(old, replace))
|
|
new.__dict__.update(old.__dict__)
|
|
|
|
|
|
code_type = type(_wrap.__code__)
|
|
|
|
# Finder/loader utility code ##################################################
|
|
|
|
def set_package(fxn):
|
|
"""Set __package__ on the returned module."""
|
|
def wrapper(*args, **kwargs):
|
|
module = fxn(*args, **kwargs)
|
|
if not hasattr(module, '__package__') or module.__package__ is None:
|
|
module.__package__ = module.__name__
|
|
if not hasattr(module, '__path__'):
|
|
module.__package__ = module.__package__.rpartition('.')[0]
|
|
return module
|
|
_wrap(wrapper, fxn)
|
|
return wrapper
|
|
|
|
|
|
def set_loader(fxn):
|
|
"""Set __loader__ on the returned module."""
|
|
def wrapper(self, *args, **kwargs):
|
|
module = fxn(self, *args, **kwargs)
|
|
if not hasattr(module, '__loader__'):
|
|
module.__loader__ = self
|
|
return module
|
|
_wrap(wrapper, fxn)
|
|
return wrapper
|
|
|
|
|
|
def module_for_loader(fxn):
|
|
"""Decorator to handle selecting the proper module for loaders.
|
|
|
|
The decorated function is passed the module to use instead of the module
|
|
name. The module passed in to the function is either from sys.modules if
|
|
it already exists or is a new module which has __name__ set and is inserted
|
|
into sys.modules. If an exception is raised and the decorator created the
|
|
module it is subsequently removed from sys.modules.
|
|
|
|
The decorator assumes that the decorated function takes the module name as
|
|
the second argument.
|
|
|
|
"""
|
|
def decorated(self, fullname, *args, **kwargs):
|
|
module = sys.modules.get(fullname)
|
|
is_reload = bool(module)
|
|
if not is_reload:
|
|
# This must be done before open() is called as the 'io' module
|
|
# implicitly imports 'locale' and would otherwise trigger an
|
|
# infinite loop.
|
|
module = imp.new_module(fullname)
|
|
sys.modules[fullname] = module
|
|
try:
|
|
return fxn(self, module, *args, **kwargs)
|
|
except:
|
|
if not is_reload:
|
|
del sys.modules[fullname]
|
|
raise
|
|
_wrap(decorated, fxn)
|
|
return decorated
|
|
|
|
|
|
def _check_name(method):
|
|
"""Decorator to verify that the module being requested matches the one the
|
|
loader can handle.
|
|
|
|
The first argument (self) must define _name which the second argument is
|
|
comapred against. If the comparison fails then ImportError is raised.
|
|
|
|
"""
|
|
def inner(self, name, *args, **kwargs):
|
|
if self._name != name:
|
|
raise ImportError("loader cannot handle %s" % name)
|
|
return method(self, name, *args, **kwargs)
|
|
_wrap(inner, method)
|
|
return inner
|
|
|
|
|
|
def _requires_builtin(fxn):
|
|
"""Decorator to verify the named module is built-in."""
|
|
def wrapper(self, fullname):
|
|
if fullname not in sys.builtin_module_names:
|
|
raise ImportError("{0} is not a built-in module".format(fullname))
|
|
return fxn(self, fullname)
|
|
_wrap(wrapper, fxn)
|
|
return wrapper
|
|
|
|
|
|
def _requires_frozen(fxn):
|
|
"""Decorator to verify the named module is frozen."""
|
|
def wrapper(self, fullname):
|
|
if not imp.is_frozen(fullname):
|
|
raise ImportError("{0} is not a frozen module".format(fullname))
|
|
return fxn(self, fullname)
|
|
_wrap(wrapper, fxn)
|
|
return wrapper
|
|
|
|
|
|
def _suffix_list(suffix_type):
|
|
"""Return a list of file suffixes based on the imp file type."""
|
|
return [suffix[0] for suffix in imp.get_suffixes()
|
|
if suffix[2] == suffix_type]
|
|
|
|
|
|
# Loaders #####################################################################
|
|
|
|
class BuiltinImporter:
|
|
|
|
"""Meta path import for built-in modules.
|
|
|
|
All methods are either class or static methods to avoid the need to
|
|
instantiate the class.
|
|
|
|
"""
|
|
|
|
@classmethod
|
|
def find_module(cls, fullname, path=None):
|
|
"""Find the built-in module.
|
|
|
|
If 'path' is ever specified then the search is considered a failure.
|
|
|
|
"""
|
|
if path is not None:
|
|
return None
|
|
return cls if imp.is_builtin(fullname) else None
|
|
|
|
@classmethod
|
|
@set_package
|
|
@set_loader
|
|
@_requires_builtin
|
|
def load_module(cls, fullname):
|
|
"""Load a built-in module."""
|
|
is_reload = fullname in sys.modules
|
|
try:
|
|
return imp.init_builtin(fullname)
|
|
except:
|
|
if not is_reload and fullname in sys.modules:
|
|
del sys.modules[fullname]
|
|
raise
|
|
|
|
@classmethod
|
|
@_requires_builtin
|
|
def get_code(cls, fullname):
|
|
"""Return None as built-in modules do not have code objects."""
|
|
return None
|
|
|
|
@classmethod
|
|
@_requires_builtin
|
|
def get_source(cls, fullname):
|
|
"""Return None as built-in modules do not have source code."""
|
|
return None
|
|
|
|
@classmethod
|
|
@_requires_builtin
|
|
def is_package(cls, fullname):
|
|
"""Return None as built-in module are never packages."""
|
|
return False
|
|
|
|
|
|
class FrozenImporter:
|
|
|
|
"""Meta path import for frozen modules.
|
|
|
|
All methods are either class or static methods to avoid the need to
|
|
instantiate the class.
|
|
|
|
"""
|
|
|
|
@classmethod
|
|
def find_module(cls, fullname, path=None):
|
|
"""Find a frozen module."""
|
|
return cls if imp.is_frozen(fullname) else None
|
|
|
|
@classmethod
|
|
@set_package
|
|
@set_loader
|
|
@_requires_frozen
|
|
def load_module(cls, fullname):
|
|
"""Load a frozen module."""
|
|
is_reload = fullname in sys.modules
|
|
try:
|
|
return imp.init_frozen(fullname)
|
|
except:
|
|
if not is_reload and fullname in sys.modules:
|
|
del sys.modules[fullname]
|
|
raise
|
|
|
|
@classmethod
|
|
@_requires_frozen
|
|
def get_code(cls, fullname):
|
|
"""Return the code object for the frozen module."""
|
|
return imp.get_frozen_object(fullname)
|
|
|
|
@classmethod
|
|
@_requires_frozen
|
|
def get_source(cls, fullname):
|
|
"""Return None as frozen modules do not have source code."""
|
|
return None
|
|
|
|
@classmethod
|
|
@_requires_frozen
|
|
def is_package(cls, fullname):
|
|
"""Return if the frozen module is a package."""
|
|
return imp.is_frozen_package(fullname)
|
|
|
|
|
|
class _LoaderBasics:
|
|
|
|
"""Base class of common code needed by both SourceLoader and
|
|
_SourcelessFileLoader."""
|
|
|
|
def is_package(self, fullname):
|
|
"""Concrete implementation of InspectLoader.is_package by checking if
|
|
the path returned by get_filename has a filename of '__init__.py'."""
|
|
filename = self.get_filename(fullname).rpartition(path_sep)[2]
|
|
return filename.rsplit('.', 1)[0] == '__init__'
|
|
|
|
def _bytes_from_bytecode(self, fullname, data, source_mtime):
|
|
"""Return the marshalled bytes from bytecode, verifying the magic
|
|
number and timestamp alon the way.
|
|
|
|
If source_mtime is None then skip the timestamp check.
|
|
|
|
"""
|
|
magic = data[:4]
|
|
raw_timestamp = data[4:8]
|
|
if len(magic) != 4 or magic != imp.get_magic():
|
|
raise ImportError("bad magic number in {}".format(fullname))
|
|
elif len(raw_timestamp) != 4:
|
|
raise EOFError("bad timestamp in {}".format(fullname))
|
|
elif source_mtime is not None:
|
|
if marshal._r_long(raw_timestamp) != source_mtime:
|
|
raise ImportError("bytecode is stale for {}".format(fullname))
|
|
# Can't return the code object as errors from marshal loading need to
|
|
# propagate even when source is available.
|
|
return data[8:]
|
|
|
|
@module_for_loader
|
|
def _load_module(self, module, *, sourceless=False):
|
|
"""Helper for load_module able to handle either source or sourceless
|
|
loading."""
|
|
name = module.__name__
|
|
code_object = self.get_code(name)
|
|
module.__file__ = self.get_filename(name)
|
|
if not sourceless:
|
|
module.__cached__ = imp.cache_from_source(module.__file__)
|
|
else:
|
|
module.__cached__ = module.__file__
|
|
module.__package__ = name
|
|
if self.is_package(name):
|
|
module.__path__ = [module.__file__.rsplit(path_sep, 1)[0]]
|
|
else:
|
|
module.__package__ = module.__package__.rpartition('.')[0]
|
|
module.__loader__ = self
|
|
exec(code_object, module.__dict__)
|
|
return module
|
|
|
|
|
|
class SourceLoader(_LoaderBasics):
|
|
|
|
def path_mtime(self, path:str) -> int:
|
|
"""Optional method that returns the modification time for the specified
|
|
path.
|
|
|
|
Implementing this method allows the loader to read bytecode files.
|
|
|
|
"""
|
|
raise NotImplementedError
|
|
|
|
def set_data(self, path:str, data:bytes) -> None:
|
|
"""Optional method which writes data to a file path.
|
|
|
|
Implementing this method allows for the writing of bytecode files.
|
|
|
|
"""
|
|
raise NotImplementedError
|
|
|
|
|
|
def get_source(self, fullname):
|
|
"""Concrete implementation of InspectLoader.get_source."""
|
|
import tokenize
|
|
path = self.get_filename(fullname)
|
|
try:
|
|
source_bytes = self.get_data(path)
|
|
except IOError:
|
|
raise ImportError("source not available through get_data()")
|
|
encoding = tokenize.detect_encoding(_io.BytesIO(source_bytes).readline)
|
|
newline_decoder = _io.IncrementalNewlineDecoder(None, True)
|
|
return newline_decoder.decode(source_bytes.decode(encoding[0]))
|
|
|
|
def get_code(self, fullname):
|
|
"""Concrete implementation of InspectLoader.get_code.
|
|
|
|
Reading of bytecode requires path_mtime to be implemented. To write
|
|
bytecode, set_data must also be implemented.
|
|
|
|
"""
|
|
source_path = self.get_filename(fullname)
|
|
bytecode_path = imp.cache_from_source(source_path)
|
|
source_mtime = None
|
|
if bytecode_path is not None:
|
|
try:
|
|
source_mtime = self.path_mtime(source_path)
|
|
except NotImplementedError:
|
|
pass
|
|
else:
|
|
try:
|
|
data = self.get_data(bytecode_path)
|
|
except IOError:
|
|
pass
|
|
else:
|
|
try:
|
|
bytes_data = self._bytes_from_bytecode(fullname, data,
|
|
source_mtime)
|
|
except (ImportError, EOFError):
|
|
pass
|
|
else:
|
|
found = marshal.loads(bytes_data)
|
|
if isinstance(found, code_type):
|
|
return found
|
|
else:
|
|
msg = "Non-code object in {}"
|
|
raise ImportError(msg.format(bytecode_path))
|
|
source_bytes = self.get_data(source_path)
|
|
code_object = compile(source_bytes, source_path, 'exec',
|
|
dont_inherit=True)
|
|
if (not sys.dont_write_bytecode and bytecode_path is not None and
|
|
source_mtime is not None):
|
|
# If e.g. Jython ever implements imp.cache_from_source to have
|
|
# their own cached file format, this block of code will most likely
|
|
# throw an exception.
|
|
data = bytearray(imp.get_magic())
|
|
data.extend(marshal._w_long(source_mtime))
|
|
data.extend(marshal.dumps(code_object))
|
|
try:
|
|
self.set_data(bytecode_path, data)
|
|
except NotImplementedError:
|
|
pass
|
|
return code_object
|
|
|
|
def load_module(self, fullname):
|
|
"""Concrete implementation of Loader.load_module.
|
|
|
|
Requires ExecutionLoader.get_filename and ResourceLoader.get_data to be
|
|
implemented to load source code. Use of bytecode is dictated by whether
|
|
get_code uses/writes bytecode.
|
|
|
|
"""
|
|
return self._load_module(fullname)
|
|
|
|
|
|
class _FileLoader:
|
|
|
|
"""Base file loader class which implements the loader protocol methods that
|
|
require file system usage."""
|
|
|
|
def __init__(self, fullname, path):
|
|
"""Cache the module name and the path to the file found by the
|
|
finder."""
|
|
self._name = fullname
|
|
self._path = path
|
|
|
|
@_check_name
|
|
def get_filename(self, fullname):
|
|
"""Return the path to the source file as found by the finder."""
|
|
return self._path
|
|
|
|
def get_data(self, path):
|
|
"""Return the data from path as raw bytes."""
|
|
with _closing(_io.FileIO(path, 'r')) as file:
|
|
return file.read()
|
|
|
|
|
|
class _SourceFileLoader(_FileLoader, SourceLoader):
|
|
|
|
"""Concrete implementation of SourceLoader using the file system."""
|
|
|
|
def path_mtime(self, path):
|
|
"""Return the modification time for the path."""
|
|
return int(_os.stat(path).st_mtime)
|
|
|
|
def set_data(self, path, data):
|
|
"""Write bytes data to a file."""
|
|
parent, _, filename = path.rpartition(path_sep)
|
|
path_parts = []
|
|
# Figure out what directories are missing.
|
|
while parent and not _path_isdir(parent):
|
|
parent, _, part = parent.rpartition(path_sep)
|
|
path_parts.append(part)
|
|
# Create needed directories.
|
|
for part in reversed(path_parts):
|
|
parent = _path_join(parent, part)
|
|
try:
|
|
_os.mkdir(parent)
|
|
except OSError as exc:
|
|
# Probably another Python process already created the dir.
|
|
if exc.errno == errno.EEXIST:
|
|
continue
|
|
else:
|
|
raise
|
|
except IOError as exc:
|
|
# If can't get proper access, then just forget about writing
|
|
# the data.
|
|
if exc.errno == errno.EACCES:
|
|
return
|
|
else:
|
|
raise
|
|
try:
|
|
with _io.FileIO(path, 'wb') as file:
|
|
file.write(data)
|
|
except IOError as exc:
|
|
# Don't worry if you can't write bytecode.
|
|
if exc.errno == errno.EACCES:
|
|
return
|
|
else:
|
|
raise
|
|
|
|
|
|
class _SourcelessFileLoader(_FileLoader, _LoaderBasics):
|
|
|
|
"""Loader which handles sourceless file imports."""
|
|
|
|
def load_module(self, fullname):
|
|
return self._load_module(fullname, sourceless=True)
|
|
|
|
def get_code(self, fullname):
|
|
path = self.get_filename(fullname)
|
|
data = self.get_data(path)
|
|
bytes_data = self._bytes_from_bytecode(fullname, data, None)
|
|
found = marshal.loads(bytes_data)
|
|
if isinstance(found, code_type):
|
|
return found
|
|
else:
|
|
raise ImportError("Non-code object in {}".format(path))
|
|
|
|
def get_source(self, fullname):
|
|
"""Return None as there is no source code."""
|
|
return None
|
|
|
|
|
|
class _ExtensionFileLoader:
|
|
|
|
"""Loader for extension modules.
|
|
|
|
The constructor is designed to work with FileFinder.
|
|
|
|
"""
|
|
|
|
def __init__(self, name, path):
|
|
"""Initialize the loader.
|
|
|
|
If is_pkg is True then an exception is raised as extension modules
|
|
cannot be the __init__ module for an extension module.
|
|
|
|
"""
|
|
self._name = name
|
|
self._path = path
|
|
|
|
@_check_name
|
|
@set_package
|
|
@set_loader
|
|
def load_module(self, fullname):
|
|
"""Load an extension module."""
|
|
is_reload = fullname in sys.modules
|
|
try:
|
|
return imp.load_dynamic(fullname, self._path)
|
|
except:
|
|
if not is_reload and fullname in sys.modules:
|
|
del sys.modules[fullname]
|
|
raise
|
|
|
|
@_check_name
|
|
def is_package(self, fullname):
|
|
"""Return False as an extension module can never be a package."""
|
|
return False
|
|
|
|
@_check_name
|
|
def get_code(self, fullname):
|
|
"""Return None as an extension module cannot create a code object."""
|
|
return None
|
|
|
|
@_check_name
|
|
def get_source(self, fullname):
|
|
"""Return None as extension modules have no source code."""
|
|
return None
|
|
|
|
|
|
# Finders #####################################################################
|
|
|
|
class PathFinder:
|
|
|
|
"""Meta path finder for sys.(path|path_hooks|path_importer_cache)."""
|
|
|
|
@classmethod
|
|
def _path_hooks(cls, path, hooks=None):
|
|
"""Search sequence of hooks for a finder for 'path'.
|
|
|
|
If 'hooks' is false then use sys.path_hooks.
|
|
|
|
"""
|
|
if not hooks:
|
|
hooks = sys.path_hooks
|
|
for hook in hooks:
|
|
try:
|
|
return hook(path)
|
|
except ImportError:
|
|
continue
|
|
else:
|
|
raise ImportError("no path hook found for {0}".format(path))
|
|
|
|
@classmethod
|
|
def _path_importer_cache(cls, path, default=None):
|
|
"""Get the finder for the path from sys.path_importer_cache.
|
|
|
|
If the path is not in the cache, find the appropriate finder and cache
|
|
it. If None is cached, get the default finder and cache that
|
|
(if applicable).
|
|
|
|
Because of NullImporter, some finder should be returned. The only
|
|
explicit fail case is if None is cached but the path cannot be used for
|
|
the default hook, for which ImportError is raised.
|
|
|
|
"""
|
|
try:
|
|
finder = sys.path_importer_cache[path]
|
|
except KeyError:
|
|
finder = cls._path_hooks(path)
|
|
sys.path_importer_cache[path] = finder
|
|
else:
|
|
if finder is None and default:
|
|
# Raises ImportError on failure.
|
|
finder = default(path)
|
|
sys.path_importer_cache[path] = finder
|
|
return finder
|
|
|
|
@classmethod
|
|
def find_module(cls, fullname, path=None):
|
|
"""Find the module on sys.path or 'path' based on sys.path_hooks and
|
|
sys.path_importer_cache."""
|
|
if not path:
|
|
path = sys.path
|
|
for entry in path:
|
|
try:
|
|
finder = cls._path_importer_cache(entry)
|
|
except ImportError:
|
|
continue
|
|
if finder:
|
|
loader = finder.find_module(fullname)
|
|
if loader:
|
|
return loader
|
|
else:
|
|
return None
|
|
|
|
|
|
class _FileFinder:
|
|
|
|
"""File-based finder.
|
|
|
|
Constructor takes a list of objects detailing what file extensions their
|
|
loader supports along with whether it can be used for a package.
|
|
|
|
"""
|
|
|
|
def __init__(self, path, *details):
|
|
"""Initialize with finder details."""
|
|
packages = []
|
|
modules = []
|
|
for detail in details:
|
|
modules.extend((suffix, detail.loader) for suffix in detail.suffixes)
|
|
if detail.supports_packages:
|
|
packages.extend((suffix, detail.loader)
|
|
for suffix in detail.suffixes)
|
|
self.packages = packages
|
|
self.modules = modules
|
|
self.path = path
|
|
|
|
def find_module(self, fullname):
|
|
"""Try to find a loader for the specified module."""
|
|
tail_module = fullname.rpartition('.')[2]
|
|
base_path = _path_join(self.path, tail_module)
|
|
if _path_isdir(base_path) and _case_ok(self.path, tail_module):
|
|
for suffix, loader in self.packages:
|
|
init_filename = '__init__' + suffix
|
|
full_path = _path_join(base_path, init_filename)
|
|
if (_path_isfile(full_path) and
|
|
_case_ok(base_path, init_filename)):
|
|
return loader(fullname, full_path)
|
|
else:
|
|
msg = "Not importing directory {}: missing __init__"
|
|
_warnings.warn(msg.format(base_path), ImportWarning)
|
|
for suffix, loader in self.modules:
|
|
mod_filename = tail_module + suffix
|
|
full_path = _path_join(self.path, mod_filename)
|
|
if _path_isfile(full_path) and _case_ok(self.path, mod_filename):
|
|
return loader(fullname, full_path)
|
|
return None
|
|
|
|
class _SourceFinderDetails:
|
|
|
|
loader = _SourceFileLoader
|
|
supports_packages = True
|
|
|
|
def __init__(self):
|
|
self.suffixes = _suffix_list(imp.PY_SOURCE)
|
|
|
|
class _SourcelessFinderDetails:
|
|
|
|
loader = _SourcelessFileLoader
|
|
supports_packages = True
|
|
|
|
def __init__(self):
|
|
self.suffixes = _suffix_list(imp.PY_COMPILED)
|
|
|
|
|
|
class _ExtensionFinderDetails:
|
|
|
|
loader = _ExtensionFileLoader
|
|
supports_packages = False
|
|
|
|
def __init__(self):
|
|
self.suffixes = _suffix_list(imp.C_EXTENSION)
|
|
|
|
|
|
# Import itself ###############################################################
|
|
|
|
def _file_path_hook(path):
|
|
"""If the path is a directory, return a file-based finder."""
|
|
if _path_isdir(path):
|
|
return _FileFinder(path, _ExtensionFinderDetails(),
|
|
_SourceFinderDetails(),
|
|
_SourcelessFinderDetails())
|
|
else:
|
|
raise ImportError("only directories are supported")
|
|
|
|
|
|
_DEFAULT_PATH_HOOK = _file_path_hook
|
|
|
|
class _DefaultPathFinder(PathFinder):
|
|
|
|
"""Subclass of PathFinder that implements implicit semantics for
|
|
__import__."""
|
|
|
|
@classmethod
|
|
def _path_hooks(cls, path):
|
|
"""Search sys.path_hooks as well as implicit path hooks."""
|
|
try:
|
|
return super()._path_hooks(path)
|
|
except ImportError:
|
|
implicit_hooks = [_DEFAULT_PATH_HOOK, imp.NullImporter]
|
|
return super()._path_hooks(path, implicit_hooks)
|
|
|
|
@classmethod
|
|
def _path_importer_cache(cls, path):
|
|
"""Use the default path hook when None is stored in
|
|
sys.path_importer_cache."""
|
|
return super()._path_importer_cache(path, _DEFAULT_PATH_HOOK)
|
|
|
|
|
|
class _ImportLockContext:
|
|
|
|
"""Context manager for the import lock."""
|
|
|
|
def __enter__(self):
|
|
"""Acquire the import lock."""
|
|
imp.acquire_lock()
|
|
|
|
def __exit__(self, exc_type, exc_value, exc_traceback):
|
|
"""Release the import lock regardless of any raised exceptions."""
|
|
imp.release_lock()
|
|
|
|
|
|
_IMPLICIT_META_PATH = [BuiltinImporter, FrozenImporter, _DefaultPathFinder]
|
|
|
|
def _gcd_import(name, package=None, level=0):
|
|
"""Import and return the module based on its name, the package the call is
|
|
being made from, and the level adjustment.
|
|
|
|
This function represents the greatest common denominator of functionality
|
|
between import_module and __import__. This includes settting __package__ if
|
|
the loader did not.
|
|
|
|
"""
|
|
if package:
|
|
if not hasattr(package, 'rindex'):
|
|
raise ValueError("__package__ not set to a string")
|
|
elif package not in sys.modules:
|
|
msg = ("Parent module {0!r} not loaded, cannot perform relative "
|
|
"import")
|
|
raise SystemError(msg.format(package))
|
|
if not name and level == 0:
|
|
raise ValueError("Empty module name")
|
|
if level > 0:
|
|
dot = len(package)
|
|
for x in range(level, 1, -1):
|
|
try:
|
|
dot = package.rindex('.', 0, dot)
|
|
except ValueError:
|
|
raise ValueError("attempted relative import beyond "
|
|
"top-level package")
|
|
if name:
|
|
name = "{0}.{1}".format(package[:dot], name)
|
|
else:
|
|
name = package[:dot]
|
|
with _ImportLockContext():
|
|
try:
|
|
module = sys.modules[name]
|
|
if module is None:
|
|
message = ("import of {} halted; "
|
|
"None in sys.modules".format(name))
|
|
raise ImportError(message)
|
|
return module
|
|
except KeyError:
|
|
pass
|
|
parent = name.rpartition('.')[0]
|
|
path = None
|
|
if parent:
|
|
if parent not in sys.modules:
|
|
_gcd_import(parent)
|
|
# Backwards-compatibility; be nicer to skip the dict lookup.
|
|
parent_module = sys.modules[parent]
|
|
try:
|
|
path = parent_module.__path__
|
|
except AttributeError:
|
|
raise ImportError("no module named {}; "
|
|
"{} is not a package".format(name, parent))
|
|
meta_path = sys.meta_path + _IMPLICIT_META_PATH
|
|
for finder in meta_path:
|
|
loader = finder.find_module(name, path)
|
|
if loader is not None:
|
|
loader.load_module(name)
|
|
break
|
|
else:
|
|
raise ImportError("No module named {0}".format(name))
|
|
# Backwards-compatibility; be nicer to skip the dict lookup.
|
|
module = sys.modules[name]
|
|
if parent:
|
|
# Set the module as an attribute on its parent.
|
|
setattr(parent_module, name.rpartition('.')[2], module)
|
|
# Set __package__ if the loader did not.
|
|
if not hasattr(module, '__package__') or module.__package__ is None:
|
|
# Watch out for what comes out of sys.modules to not be a module,
|
|
# e.g. an int.
|
|
try:
|
|
module.__package__ = module.__name__
|
|
if not hasattr(module, '__path__'):
|
|
module.__package__ = module.__package__.rpartition('.')[0]
|
|
except AttributeError:
|
|
pass
|
|
return module
|
|
|
|
|
|
def __import__(name, globals={}, locals={}, fromlist=[], level=0):
|
|
"""Import a module.
|
|
|
|
The 'globals' argument is used to infer where the import is occuring from
|
|
to handle relative imports. The 'locals' argument is ignored. The
|
|
'fromlist' argument specifies what should exist as attributes on the module
|
|
being imported (e.g. ``from module import <fromlist>``). The 'level'
|
|
argument represents the package location to import from in a relative
|
|
import (e.g. ``from ..pkg import mod`` would have a 'level' of 2).
|
|
|
|
"""
|
|
if not hasattr(name, 'rpartition'):
|
|
raise TypeError("module name must be str, not {}".format(type(name)))
|
|
if level == 0:
|
|
module = _gcd_import(name)
|
|
else:
|
|
# __package__ is not guaranteed to be defined or could be set to None
|
|
# to represent that it's proper value is unknown
|
|
package = globals.get('__package__')
|
|
if package is None:
|
|
package = globals['__name__']
|
|
if '__path__' not in globals:
|
|
package = package.rpartition('.')[0]
|
|
module = _gcd_import(name, package, level)
|
|
# The hell that is fromlist ...
|
|
if not fromlist:
|
|
# Return up to the first dot in 'name'. This is complicated by the fact
|
|
# that 'name' may be relative.
|
|
if level == 0:
|
|
return sys.modules[name.partition('.')[0]]
|
|
elif not name:
|
|
return module
|
|
else:
|
|
cut_off = len(name) - len(name.partition('.')[0])
|
|
return sys.modules[module.__name__[:-cut_off]]
|
|
else:
|
|
# If a package was imported, try to import stuff from fromlist.
|
|
if hasattr(module, '__path__'):
|
|
if '*' in fromlist and hasattr(module, '__all__'):
|
|
fromlist = list(fromlist)
|
|
fromlist.remove('*')
|
|
fromlist.extend(module.__all__)
|
|
for x in (y for y in fromlist if not hasattr(module,y)):
|
|
try:
|
|
_gcd_import('{0}.{1}'.format(module.__name__, x))
|
|
except ImportError:
|
|
pass
|
|
return module
|