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"""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.
"""
#
# IMPORTANT: Whenever making changes to this module, be sure to run
# a top-level make in order to get the frozen version of the module
# update. Not doing so will result in the Makefile to fail for
# all others who don't have a ./python around to freeze the module
# in the early stages of compilation.
#
# See importlib._setup() for what is injected into the global namespace.
# 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 ######################################################
_CASE_INSENSITIVE_PLATFORMS = 'win', 'cygwin', 'darwin'
def _make_relax_case():
if sys.platform.startswith(_CASE_INSENSITIVE_PLATFORMS):
def _relax_case():
"""True if filenames must be checked case-insensitively."""
return b'PYTHONCASEOK' in _os.environ
else:
def _relax_case():
"""True if filenames must be checked case-insensitively."""
return False
return _relax_case
def _w_long(x):
"""Convert a 32-bit integer to little-endian."""
return (int(x) & 0xFFFFFFFF).to_bytes(4, 'little')
def _r_long(int_bytes):
"""Convert 4 bytes in little-endian to an integer."""
return int.from_bytes(int_bytes, 'little')
def _path_join(*path_parts):
"""Replacement for os.path.join()."""
return path_sep.join([part.rstrip(path_separators)
for part in path_parts if part])
def _path_split(path):
"""Replacement for os.path.split()."""
if len(path_separators) == 1:
front, _, tail = path.rpartition(path_sep)
return front, tail
for x in reversed(path):
if x in path_separators:
front, tail = path.rsplit(x, maxsplit=1)
return front, tail
return '', path
def _path_stat(path):
"""Stat the path.
Made a separate function to make it easier to override in experiments
(e.g. cache stat results).
"""
return _os.stat(path)
def _path_is_mode_type(path, mode):
"""Test whether the path is the specified mode type."""
try:
stat_info = _path_stat(path)
except OSError:
return False
return (stat_info.st_mode & 0o170000) == mode
def _path_isfile(path):
"""Replacement for os.path.isfile."""
return _path_is_mode_type(path, 0o100000)
def _path_isdir(path):
"""Replacement for os.path.isdir."""
if not path:
path = _os.getcwd()
return _path_is_mode_type(path, 0o040000)
def _write_atomic(path, data, mode=0o666):
"""Best-effort function to write data to a path atomically.
Be prepared to handle a FileExistsError if concurrent writing of the
temporary file is attempted."""
# id() is used to generate a pseudo-random filename.
path_tmp = '{}.{}'.format(path, id(path))
fd = _os.open(path_tmp,
_os.O_EXCL | _os.O_CREAT | _os.O_WRONLY, mode & 0o666)
try:
# We first write data to a temporary file, and then use os.replace() to
# perform an atomic rename.
with _io.FileIO(fd, 'wb') as file:
file.write(data)
_os.replace(path_tmp, path)
except OSError:
try:
_os.unlink(path_tmp)
except OSError:
pass
raise
def _wrap(new, old):
"""Simple substitute for functools.update_wrapper."""
for replace in ['__module__', '__name__', '__qualname__', '__doc__']:
if hasattr(old, replace):
setattr(new, replace, getattr(old, replace))
new.__dict__.update(old.__dict__)
def _new_module(name):
return type(sys)(name)
_code_type = type(_wrap.__code__)
class _ManageReload:
"""Manages the possible clean-up of sys.modules for load_module()."""
def __init__(self, name):
self._name = name
def __enter__(self):
self._is_reload = self._name in sys.modules
def __exit__(self, *args):
if any(arg is not None for arg in args) and not self._is_reload:
try:
del sys.modules[self._name]
except KeyError:
pass
# Module-level locking ########################################################
# A dict mapping module names to weakrefs of _ModuleLock instances
_module_locks = {}
# A dict mapping thread ids to _ModuleLock instances
_blocking_on = {}
class _DeadlockError(RuntimeError):
pass
class _ModuleLock:
"""A recursive lock implementation which is able to detect deadlocks
(e.g. thread 1 trying to take locks A then B, and thread 2 trying to
take locks B then A).
"""
def __init__(self, name):
self.lock = _thread.allocate_lock()
self.wakeup = _thread.allocate_lock()
self.name = name
self.owner = None
self.count = 0
self.waiters = 0
def has_deadlock(self):
# Deadlock avoidance for concurrent circular imports.
me = _thread.get_ident()
tid = self.owner
while True:
lock = _blocking_on.get(tid)
if lock is None:
return False
tid = lock.owner
if tid == me:
return True
def acquire(self):
"""
Acquire the module lock. If a potential deadlock is detected,
a _DeadlockError is raised.
Otherwise, the lock is always acquired and True is returned.
"""
tid = _thread.get_ident()
_blocking_on[tid] = self
try:
while True:
with self.lock:
if self.count == 0 or self.owner == tid:
self.owner = tid
self.count += 1
return True
if self.has_deadlock():
raise _DeadlockError('deadlock detected by %r' % self)
if self.wakeup.acquire(False):
self.waiters += 1
# Wait for a release() call
self.wakeup.acquire()
self.wakeup.release()
finally:
del _blocking_on[tid]
def release(self):
tid = _thread.get_ident()
with self.lock:
if self.owner != tid:
raise RuntimeError('cannot release un-acquired lock')
assert self.count > 0
self.count -= 1
if self.count == 0:
self.owner = None
if self.waiters:
self.waiters -= 1
self.wakeup.release()
def __repr__(self):
return '_ModuleLock({!r}) at {}'.format(self.name, id(self))
class _DummyModuleLock:
"""A simple _ModuleLock equivalent for Python builds without
multi-threading support."""
def __init__(self, name):
self.name = name
self.count = 0
def acquire(self):
self.count += 1
return True
def release(self):
if self.count == 0:
raise RuntimeError('cannot release un-acquired lock')
self.count -= 1
def __repr__(self):
return '_DummyModuleLock({!r}) at {}'.format(self.name, id(self))
class _ModuleLockManager:
def __init__(self, name):
self._name = name
self._lock = None
def __enter__(self):
try:
self._lock = _get_module_lock(self._name)
finally:
_imp.release_lock()
self._lock.acquire()
def __exit__(self, *args, **kwargs):
self._lock.release()
# The following two functions are for consumption by Python/import.c.
def _get_module_lock(name):
"""Get or create the module lock for a given module name.
Should only be called with the import lock taken."""
lock = None
try:
lock = _module_locks[name]()
except KeyError:
pass
if lock is None:
if _thread is None:
lock = _DummyModuleLock(name)
else:
lock = _ModuleLock(name)
def cb(_):
del _module_locks[name]
_module_locks[name] = _weakref.ref(lock, cb)
return lock
def _lock_unlock_module(name):
"""Release the global import lock, and acquires then release the
module lock for a given module name.
This is used to ensure a module is completely initialized, in the
event it is being imported by another thread.
Should only be called with the import lock taken."""
lock = _get_module_lock(name)
_imp.release_lock()
try:
lock.acquire()
except _DeadlockError:
# Concurrent circular import, we'll accept a partially initialized
# module object.
pass
else:
lock.release()
# Frame stripping magic ###############################################
def _call_with_frames_removed(f, *args, **kwds):
"""remove_importlib_frames in import.c will always remove sequences
of importlib frames that end with a call to this function
Use it instead of a normal call in places where including the importlib
frames introduces unwanted noise into the traceback (e.g. when executing
module code)
"""
return f(*args, **kwds)
# Finder/loader utility code ###############################################
# Magic word to reject .pyc files generated by other Python versions.
# It should change for each incompatible change to the bytecode.
#
# The value of CR and LF is incorporated so if you ever read or write
# a .pyc file in text mode the magic number will be wrong; also, the
# Apple MPW compiler swaps their values, botching string constants.
#
# The magic numbers must be spaced apart at least 2 values, as the
# -U interpeter flag will cause MAGIC+1 being used. They have been
# odd numbers for some time now.
#
# There were a variety of old schemes for setting the magic number.
# The current working scheme is to increment the previous value by
# 10.
#
# Starting with the adoption of PEP 3147 in Python 3.2, every bump in magic
# number also includes a new "magic tag", i.e. a human readable string used
# to represent the magic number in __pycache__ directories. When you change
# the magic number, you must also set a new unique magic tag. Generally this
# can be named after the Python major version of the magic number bump, but
# it can really be anything, as long as it's different than anything else
# that's come before. The tags are included in the following table, starting
# with Python 3.2a0.
#
# Known values:
# Python 1.5: 20121
# Python 1.5.1: 20121
# Python 1.5.2: 20121
# Python 1.6: 50428
# Python 2.0: 50823
# Python 2.0.1: 50823
# Python 2.1: 60202
# Python 2.1.1: 60202
# Python 2.1.2: 60202
# Python 2.2: 60717
# Python 2.3a0: 62011
# Python 2.3a0: 62021
# Python 2.3a0: 62011 (!)
# Python 2.4a0: 62041
# Python 2.4a3: 62051
# Python 2.4b1: 62061
# Python 2.5a0: 62071
# Python 2.5a0: 62081 (ast-branch)
# Python 2.5a0: 62091 (with)
# Python 2.5a0: 62092 (changed WITH_CLEANUP opcode)
# Python 2.5b3: 62101 (fix wrong code: for x, in ...)
# Python 2.5b3: 62111 (fix wrong code: x += yield)
# Python 2.5c1: 62121 (fix wrong lnotab with for loops and
# storing constants that should have been removed)
# Python 2.5c2: 62131 (fix wrong code: for x, in ... in listcomp/genexp)
# Python 2.6a0: 62151 (peephole optimizations and STORE_MAP opcode)
# Python 2.6a1: 62161 (WITH_CLEANUP optimization)
# Python 2.7a0: 62171 (optimize list comprehensions/change LIST_APPEND)
# Python 2.7a0: 62181 (optimize conditional branches:
# introduce POP_JUMP_IF_FALSE and POP_JUMP_IF_TRUE)
# Python 2.7a0 62191 (introduce SETUP_WITH)
# Python 2.7a0 62201 (introduce BUILD_SET)
# Python 2.7a0 62211 (introduce MAP_ADD and SET_ADD)
# Python 3000: 3000
# 3010 (removed UNARY_CONVERT)
# 3020 (added BUILD_SET)
# 3030 (added keyword-only parameters)
# 3040 (added signature annotations)
# 3050 (print becomes a function)
# 3060 (PEP 3115 metaclass syntax)
# 3061 (string literals become unicode)
# 3071 (PEP 3109 raise changes)
# 3081 (PEP 3137 make __file__ and __name__ unicode)
# 3091 (kill str8 interning)
# 3101 (merge from 2.6a0, see 62151)
# 3103 (__file__ points to source file)
# Python 3.0a4: 3111 (WITH_CLEANUP optimization).
# Python 3.0a5: 3131 (lexical exception stacking, including POP_EXCEPT)
# Python 3.1a0: 3141 (optimize list, set and dict comprehensions:
# change LIST_APPEND and SET_ADD, add MAP_ADD)
# Python 3.1a0: 3151 (optimize conditional branches:
# introduce POP_JUMP_IF_FALSE and POP_JUMP_IF_TRUE)
# Python 3.2a0: 3160 (add SETUP_WITH)
# tag: cpython-32
# Python 3.2a1: 3170 (add DUP_TOP_TWO, remove DUP_TOPX and ROT_FOUR)
# tag: cpython-32
# Python 3.2a2 3180 (add DELETE_DEREF)
# Python 3.3a0 3190 __class__ super closure changed
# Python 3.3a0 3200 (__qualname__ added)
# 3210 (added size modulo 2**32 to the pyc header)
# Python 3.3a1 3220 (changed PEP 380 implementation)
# Python 3.3a4 3230 (revert changes to implicit __class__ closure)
# Python 3.4a1 3250 (evaluate positional default arguments before
# keyword-only defaults)
# Python 3.4a1 3260 (add LOAD_CLASSDEREF; allow locals of class to override
# free vars)
# Python 3.4a1 3270 (various tweaks to the __class__ closure)
# Python 3.4a1 3280 (remove implicit class argument)
# Python 3.4a4 3290 (changes to __qualname__ computation)
# Python 3.4a4 3300 (more changes to __qualname__ computation)
# Python 3.4rc2 3310 (alter __qualname__ computation)
#
# MAGIC must change whenever the bytecode emitted by the compiler may no
# longer be understood by older implementations of the eval loop (usually
# due to the addition of new opcodes).
MAGIC_NUMBER = (3310).to_bytes(2, 'little') + b'\r\n'
_RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little') # For import.c
_PYCACHE = '__pycache__'
SOURCE_SUFFIXES = ['.py'] # _setup() adds .pyw as needed.
DEBUG_BYTECODE_SUFFIXES = ['.pyc']
OPTIMIZED_BYTECODE_SUFFIXES = ['.pyo']
def cache_from_source(path, debug_override=None):
"""Given the path to a .py file, return the path to its .pyc/.pyo file.
The .py file does not need to exist; this simply returns the path to the
.pyc/.pyo file calculated as if the .py file were imported. The extension
will be .pyc unless sys.flags.optimize is non-zero, then it will be .pyo.
If debug_override is not None, then it must be a boolean and is used in
place of sys.flags.optimize.
If sys.implementation.cache_tag is None then NotImplementedError is raised.
"""
debug = not sys.flags.optimize if debug_override is None else debug_override
if debug:
suffixes = DEBUG_BYTECODE_SUFFIXES
else:
suffixes = OPTIMIZED_BYTECODE_SUFFIXES
head, tail = _path_split(path)
base_filename, sep, _ = tail.partition('.')
tag = sys.implementation.cache_tag
if tag is None:
raise NotImplementedError('sys.implementation.cache_tag is None')
filename = ''.join([base_filename, sep, tag, suffixes[0]])
return _path_join(head, _PYCACHE, filename)
def source_from_cache(path):
"""Given the path to a .pyc./.pyo file, return the path to its .py file.
The .pyc/.pyo file does not need to exist; this simply returns the path to
the .py file calculated to correspond to the .pyc/.pyo file. If path does
not conform to PEP 3147 format, ValueError will be raised. If
sys.implementation.cache_tag is None then NotImplementedError is raised.
"""
if sys.implementation.cache_tag is None:
raise NotImplementedError('sys.implementation.cache_tag is None')
head, pycache_filename = _path_split(path)
head, pycache = _path_split(head)
if pycache != _PYCACHE:
raise ValueError('{} not bottom-level directory in '
'{!r}'.format(_PYCACHE, path))
if pycache_filename.count('.') != 2:
raise ValueError('expected only 2 dots in '
'{!r}'.format(pycache_filename))
base_filename = pycache_filename.partition('.')[0]
return _path_join(head, base_filename + SOURCE_SUFFIXES[0])
def _get_sourcefile(bytecode_path):
"""Convert a bytecode file path to a source path (if possible).
This function exists purely for backwards-compatibility for
PyImport_ExecCodeModuleWithFilenames() in the C API.
"""
if len(bytecode_path) == 0:
return None
rest, _, extension = bytecode_path.rpartition('.')
if not rest or extension.lower()[-3:-1] != 'py':
return bytecode_path
try:
source_path = source_from_cache(bytecode_path)
except (NotImplementedError, ValueError):
source_path = bytecode_path[:-1]
return source_path if _path_isfile(source_path) else bytecode_path
def _calc_mode(path):
"""Calculate the mode permissions for a bytecode file."""
try:
mode = _path_stat(path).st_mode
except OSError:
mode = 0o666
# We always ensure write access so we can update cached files
# later even when the source files are read-only on Windows (#6074)
mode |= 0o200
return mode
def _verbose_message(message, *args, verbosity=1):
"""Print the message to stderr if -v/PYTHONVERBOSE is turned on."""
if sys.flags.verbose >= verbosity:
if not message.startswith(('#', 'import ')):
message = '# ' + message
print(message.format(*args), file=sys.stderr)
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
compared against. If the comparison fails then ImportError is raised.
"""
def _check_name_wrapper(self, name=None, *args, **kwargs):
if name is None:
name = self.name
elif self.name != name:
raise ImportError('loader cannot handle %s' % name, name=name)
return method(self, name, *args, **kwargs)
_wrap(_check_name_wrapper, method)
return _check_name_wrapper
def _requires_builtin(fxn):
"""Decorator to verify the named module is built-in."""
def _requires_builtin_wrapper(self, fullname):
if fullname not in sys.builtin_module_names:
raise ImportError('{!r} is not a built-in module'.format(fullname),
name=fullname)
return fxn(self, fullname)
_wrap(_requires_builtin_wrapper, fxn)
return _requires_builtin_wrapper
def _requires_frozen(fxn):
"""Decorator to verify the named module is frozen."""
def _requires_frozen_wrapper(self, fullname):
if not _imp.is_frozen(fullname):
raise ImportError('{!r} is not a frozen module'.format(fullname),
name=fullname)
return fxn(self, fullname)
_wrap(_requires_frozen_wrapper, fxn)
return _requires_frozen_wrapper
def _find_module_shim(self, fullname):
"""Try to find a loader for the specified module by delegating to
self.find_loader().
This method is deprecated in favor of finder.find_spec().
"""
# Call find_loader(). If it returns a string (indicating this
# is a namespace package portion), generate a warning and
# return None.
loader, portions = self.find_loader(fullname)
if loader is None and len(portions):
msg = 'Not importing directory {}: missing __init__'
_warnings.warn(msg.format(portions[0]), ImportWarning)
return loader
def _load_module_shim(self, fullname):
"""Load the specified module into sys.modules and return it.
This method is deprecated. Use loader.exec_module instead.
"""
spec = spec_from_loader(fullname, self)
methods = _SpecMethods(spec)
if fullname in sys.modules:
module = sys.modules[fullname]
methods.exec(module)
return sys.modules[fullname]
else:
return methods.load()
def _validate_bytecode_header(data, source_stats=None, name=None, path=None):
"""Validate the header of the passed-in bytecode against source_stats (if
given) and returning the bytecode that can be compiled by compile().
All other arguments are used to enhance error reporting.
ImportError is raised when the magic number is incorrect or the bytecode is
found to be stale. EOFError is raised when the data is found to be
truncated.
"""
exc_details = {}
if name is not None:
exc_details['name'] = name
else:
# To prevent having to make all messages have a conditional name.
name = '<bytecode>'
if path is not None:
exc_details['path'] = path
magic = data[:4]
raw_timestamp = data[4:8]
raw_size = data[8:12]
if magic != MAGIC_NUMBER:
message = 'bad magic number in {!r}: {!r}'.format(name, magic)
_verbose_message(message)
raise ImportError(message, **exc_details)
elif len(raw_timestamp) != 4:
message = 'reached EOF while reading timestamp in {!r}'.format(name)
_verbose_message(message)
raise EOFError(message)
elif len(raw_size) != 4:
message = 'reached EOF while reading size of source in {!r}'.format(name)
_verbose_message(message)
raise EOFError(message)
if source_stats is not None:
try:
source_mtime = int(source_stats['mtime'])
except KeyError:
pass
else:
if _r_long(raw_timestamp) != source_mtime:
message = 'bytecode is stale for {!r}'.format(name)
_verbose_message(message)
raise ImportError(message, **exc_details)
try:
source_size = source_stats['size'] & 0xFFFFFFFF
except KeyError:
pass
else:
if _r_long(raw_size) != source_size:
raise ImportError('bytecode is stale for {!r}'.format(name),
**exc_details)
return data[12:]
def _compile_bytecode(data, name=None, bytecode_path=None, source_path=None):
"""Compile bytecode as returned by _validate_bytecode_header()."""
code = marshal.loads(data)
if isinstance(code, _code_type):
_verbose_message('code object from {!r}', bytecode_path)
if source_path is not None:
_imp._fix_co_filename(code, source_path)
return code
else:
raise ImportError('Non-code object in {!r}'.format(bytecode_path),
name=name, path=bytecode_path)
def _code_to_bytecode(code, mtime=0, source_size=0):
"""Compile a code object into bytecode for writing out to a byte-compiled
file."""
data = bytearray(MAGIC_NUMBER)
data.extend(_w_long(mtime))
data.extend(_w_long(source_size))
data.extend(marshal.dumps(code))
return data
def decode_source(source_bytes):
"""Decode bytes representing source code and return the string.
Universal newline support is used in the decoding.
"""
import tokenize # To avoid bootstrap issues.
source_bytes_readline = _io.BytesIO(source_bytes).readline
encoding = tokenize.detect_encoding(source_bytes_readline)
newline_decoder = _io.IncrementalNewlineDecoder(None, True)
return newline_decoder.decode(source_bytes.decode(encoding[0]))
# Module specifications #######################################################
def _module_repr(module):
# The implementation of ModuleType__repr__().
loader = getattr(module, '__loader__', None)
if hasattr(loader, 'module_repr'):
# As soon as BuiltinImporter, FrozenImporter, and NamespaceLoader
# drop their implementations for module_repr. we can add a
# deprecation warning here.
try:
return loader.module_repr(module)
except Exception:
pass
try:
spec = module.__spec__
except AttributeError:
pass
else:
if spec is not None:
return _SpecMethods(spec).module_repr()
# We could use module.__class__.__name__ instead of 'module' in the
# various repr permutations.
try:
name = module.__name__
except AttributeError:
name = '?'
try:
filename = module.__file__
except AttributeError:
if loader is None:
return '<module {!r}>'.format(name)
else:
return '<module {!r} ({!r})>'.format(name, loader)
else:
return '<module {!r} from {!r}>'.format(name, filename)
class _installed_safely:
def __init__(self, module):
self._module = module
self._spec = module.__spec__
def __enter__(self):
# This must be done before putting the module in sys.modules
# (otherwise an optimization shortcut in import.c becomes
# wrong)
self._spec._initializing = True
sys.modules[self._spec.name] = self._module
def __exit__(self, *args):
try:
spec = self._spec
if any(arg is not None for arg in args):
try:
del sys.modules[spec.name]
except KeyError:
pass
else:
_verbose_message('import {!r} # {!r}', spec.name, spec.loader)
finally:
self._spec._initializing = False
class ModuleSpec:
"""The specification for a module, used for loading.
A module's spec is the source for information about the module. For
data associated with the module, including source, use the spec's
loader.
`name` is the absolute name of the module. `loader` is the loader
to use when loading the module. `parent` is the name of the
package the module is in. The parent is derived from the name.
`is_package` determines if the module is considered a package or
not. On modules this is reflected by the `__path__` attribute.
`origin` is the specific location used by the loader from which to
load the module, if that information is available. When filename is
set, origin will match.
`has_location` indicates that a spec's "origin" reflects a location.
When this is True, `__file__` attribute of the module is set.
`cached` is the location of the cached bytecode file, if any. It
corresponds to the `__cached__` attribute.
`submodule_search_locations` is the sequence of path entries to
search when importing submodules. If set, is_package should be
True--and False otherwise.
Packages are simply modules that (may) have submodules. If a spec
has a non-None value in `submodule_search_locations`, the import
system will consider modules loaded from the spec as packages.
Only finders (see importlib.abc.MetaPathFinder and
importlib.abc.PathEntryFinder) should modify ModuleSpec instances.
"""
def __init__(self, name, loader, *, origin=None, loader_state=None,
is_package=None):
self.name = name
self.loader = loader
self.origin = origin
self.loader_state = loader_state
self.submodule_search_locations = [] if is_package else None
# file-location attributes
self._set_fileattr = False
self._cached = None
def __repr__(self):
args = ['name={!r}'.format(self.name),
'loader={!r}'.format(self.loader)]
if self.origin is not None:
args.append('origin={!r}'.format(self.origin))
if self.submodule_search_locations is not None:
args.append('submodule_search_locations={}'
.format(self.submodule_search_locations))
return '{}({})'.format(self.__class__.__name__, ', '.join(args))
def __eq__(self, other):
smsl = self.submodule_search_locations
try:
return (self.name == other.name and
self.loader == other.loader and
self.origin == other.origin and
smsl == other.submodule_search_locations and
self.cached == other.cached and
self.has_location == other.has_location)
except AttributeError:
return False
@property
def cached(self):
if self._cached is None:
if self.origin is not None and self._set_fileattr:
filename = self.origin
if filename.endswith(tuple(SOURCE_SUFFIXES)):
try:
self._cached = cache_from_source(filename)
except NotImplementedError:
pass
elif filename.endswith(tuple(BYTECODE_SUFFIXES)):
self._cached = filename
return self._cached
@cached.setter
def cached(self, cached):
self._cached = cached
@property
def parent(self):
"""The name of the module's parent."""
if self.submodule_search_locations is None:
return self.name.rpartition('.')[0]
else:
return self.name
@property
def has_location(self):
return self._set_fileattr
@has_location.setter
def has_location(self, value):
self._set_fileattr = bool(value)
def spec_from_loader(name, loader, *, origin=None, is_package=None):
"""Return a module spec based on various loader methods."""
if hasattr(loader, 'get_filename'):
if is_package is None:
return spec_from_file_location(name, loader=loader)
search = [] if is_package else None
return spec_from_file_location(name, loader=loader,
submodule_search_locations=search)
if is_package is None:
if hasattr(loader, 'is_package'):
try:
is_package = loader.is_package(name)
except ImportError:
is_package = None # aka, undefined
else:
# the default
is_package = False
return ModuleSpec(name, loader, origin=origin, is_package=is_package)
_POPULATE = object()
def spec_from_file_location(name, location=None, *, loader=None,
submodule_search_locations=_POPULATE):
"""Return a module spec based on a file location.
To indicate that the module is a package, set
submodule_search_locations to a list of directory paths. An
empty list is sufficient, though its not otherwise useful to the
import system.
The loader must take a spec as its only __init__() arg.
"""
if location is None:
# The caller may simply want a partially populated location-
# oriented spec. So we set the location to a bogus value and
# fill in as much as we can.
location = '<unknown>'
if hasattr(loader, 'get_filename'):
# ExecutionLoader
try:
location = loader.get_filename(name)
except ImportError:
pass
# If the location is on the filesystem, but doesn't actually exist,
# we could return None here, indicating that the location is not
# valid. However, we don't have a good way of testing since an
# indirect location (e.g. a zip file or URL) will look like a
# non-existent file relative to the filesystem.
spec = ModuleSpec(name, loader, origin=location)
spec._set_fileattr = True
# Pick a loader if one wasn't provided.
if loader is None:
for loader_class, suffixes in _get_supported_file_loaders():
if location.endswith(tuple(suffixes)):
loader = loader_class(name, location)
spec.loader = loader
break
else:
return None
# Set submodule_search_paths appropriately.
if submodule_search_locations is _POPULATE:
# Check the loader.
if hasattr(loader, 'is_package'):
try:
is_package = loader.is_package(name)
except ImportError:
pass
else:
if is_package:
spec.submodule_search_locations = []
else:
spec.submodule_search_locations = submodule_search_locations
if spec.submodule_search_locations == []:
if location:
dirname = _path_split(location)[0]
spec.submodule_search_locations.append(dirname)
return spec
def _spec_from_module(module, loader=None, origin=None):
# This function is meant for use in _setup().
try:
spec = module.__spec__
except AttributeError:
pass
else:
if spec is not None:
return spec
name = module.__name__
if loader is None:
try:
loader = module.__loader__
except AttributeError:
# loader will stay None.
pass
try:
location = module.__file__
except AttributeError:
location = None
if origin is None:
if location is None:
try:
origin = loader._ORIGIN
except AttributeError:
origin = None
else:
origin = location
try:
cached = module.__cached__
except AttributeError:
cached = None
try:
submodule_search_locations = list(module.__path__)
except AttributeError:
submodule_search_locations = None
spec = ModuleSpec(name, loader, origin=origin)
spec._set_fileattr = False if location is None else True
spec.cached = cached
spec.submodule_search_locations = submodule_search_locations
return spec
class _SpecMethods:
"""Convenience wrapper around spec objects to provide spec-specific
methods."""
# The various spec_from_* functions could be made factory methods here.
def __init__(self, spec):
You can’t perform that action at this time.