mirror of
https://github.com/python/cpython.git
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1488 lines
51 KiB
Python
1488 lines
51 KiB
Python
"""Core implementation of import.
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This module is NOT meant to be directly imported! It has been designed such
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that it can be bootstrapped into Python as the implementation of import. As
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such it requires the injection of specific modules and attributes in order to
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work. One should use importlib as the public-facing version of this module.
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"""
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#
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# IMPORTANT: Whenever making changes to this module, be sure to run
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# a top-level make in order to get the frozen version of the module
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# update. Not doing so, will result in the Makefile to fail for
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# all others who don't have a ./python around to freeze the module
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# in the early stages of compilation.
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#
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# See importlib._setup() for what is injected into the global namespace.
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# When editing this code be aware that code executed at import time CANNOT
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# reference any injected objects! This includes not only global code but also
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# anything specified at the class level.
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# XXX Make sure all public names have no single leading underscore and all
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# others do.
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# Bootstrap-related code ######################################################
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_CASE_INSENSITIVE_PLATFORMS = 'win', 'cygwin', 'darwin'
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def _make_relax_case():
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if sys.platform.startswith(_CASE_INSENSITIVE_PLATFORMS):
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def _relax_case():
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"""True if filenames must be checked case-insensitively."""
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return b'PYTHONCASEOK' in _os.environ
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else:
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def _relax_case():
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"""True if filenames must be checked case-insensitively."""
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return False
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return _relax_case
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# TODO: Expose from marshal
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def _w_long(x):
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"""Convert a 32-bit integer to little-endian.
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XXX Temporary until marshal's long functions are exposed.
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"""
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x = int(x)
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int_bytes = []
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int_bytes.append(x & 0xFF)
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int_bytes.append((x >> 8) & 0xFF)
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int_bytes.append((x >> 16) & 0xFF)
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int_bytes.append((x >> 24) & 0xFF)
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return bytearray(int_bytes)
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# TODO: Expose from marshal
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def _r_long(int_bytes):
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"""Convert 4 bytes in little-endian to an integer.
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XXX Temporary until marshal's long function are exposed.
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"""
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x = int_bytes[0]
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x |= int_bytes[1] << 8
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x |= int_bytes[2] << 16
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x |= int_bytes[3] << 24
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return x
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def _path_join(*path_parts):
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"""Replacement for os.path.join()."""
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new_parts = []
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for part in path_parts:
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if not part:
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continue
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new_parts.append(part)
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if part[-1] not in path_separators:
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new_parts.append(path_sep)
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return ''.join(new_parts[:-1]) # Drop superfluous path separator.
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def _path_split(path):
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"""Replacement for os.path.split()."""
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for x in reversed(path):
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if x in path_separators:
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sep = x
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break
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else:
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sep = path_sep
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front, _, tail = path.rpartition(sep)
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return front, tail
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def _path_is_mode_type(path, mode):
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"""Test whether the path is the specified mode type."""
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try:
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stat_info = _os.stat(path)
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except OSError:
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return False
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return (stat_info.st_mode & 0o170000) == mode
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# XXX Could also expose Modules/getpath.c:isfile()
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def _path_isfile(path):
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"""Replacement for os.path.isfile."""
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return _path_is_mode_type(path, 0o100000)
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# XXX Could also expose Modules/getpath.c:isdir()
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def _path_isdir(path):
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"""Replacement for os.path.isdir."""
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if not path:
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path = _os.getcwd()
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return _path_is_mode_type(path, 0o040000)
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def _write_atomic(path, data):
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"""Best-effort function to write data to a path atomically.
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Be prepared to handle a FileExistsError if concurrent writing of the
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temporary file is attempted."""
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# id() is used to generate a pseudo-random filename.
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path_tmp = '{}.{}'.format(path, id(path))
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fd = _os.open(path_tmp, _os.O_EXCL | _os.O_CREAT | _os.O_WRONLY, 0o666)
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try:
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# We first write data to a temporary file, and then use os.replace() to
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# perform an atomic rename.
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with _io.FileIO(fd, 'wb') as file:
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file.write(data)
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_os.replace(path_tmp, path)
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except OSError:
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try:
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_os.unlink(path_tmp)
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except OSError:
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pass
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raise
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def _wrap(new, old):
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"""Simple substitute for functools.update_wrapper."""
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for replace in ['__module__', '__name__', '__qualname__', '__doc__']:
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if hasattr(old, replace):
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setattr(new, replace, getattr(old, replace))
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new.__dict__.update(old.__dict__)
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_code_type = type(_wrap.__code__)
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def new_module(name):
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"""Create a new module.
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The module is not entered into sys.modules.
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"""
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return type(_io)(name)
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# Module-level locking ########################################################
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# A dict mapping module names to weakrefs of _ModuleLock instances
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_module_locks = {}
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# A dict mapping thread ids to _ModuleLock instances
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_blocking_on = {}
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class _DeadlockError(RuntimeError):
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pass
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class _ModuleLock:
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"""A recursive lock implementation which is able to detect deadlocks
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(e.g. thread 1 trying to take locks A then B, and thread 2 trying to
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take locks B then A).
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"""
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def __init__(self, name):
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self.lock = _thread.allocate_lock()
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self.wakeup = _thread.allocate_lock()
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self.name = name
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self.owner = None
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self.count = 0
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self.waiters = 0
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def has_deadlock(self):
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# Deadlock avoidance for concurrent circular imports.
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me = _thread.get_ident()
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tid = self.owner
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while True:
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lock = _blocking_on.get(tid)
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if lock is None:
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return False
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tid = lock.owner
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if tid == me:
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return True
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def acquire(self):
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"""
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Acquire the module lock. If a potential deadlock is detected,
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a _DeadlockError is raised.
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Otherwise, the lock is always acquired and True is returned.
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"""
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tid = _thread.get_ident()
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_blocking_on[tid] = self
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try:
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while True:
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with self.lock:
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if self.count == 0 or self.owner == tid:
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self.owner = tid
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self.count += 1
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return True
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if self.has_deadlock():
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raise _DeadlockError("deadlock detected by %r" % self)
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if self.wakeup.acquire(False):
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self.waiters += 1
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# Wait for a release() call
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self.wakeup.acquire()
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self.wakeup.release()
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finally:
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del _blocking_on[tid]
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def release(self):
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tid = _thread.get_ident()
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with self.lock:
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if self.owner != tid:
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raise RuntimeError("cannot release un-acquired lock")
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assert self.count > 0
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self.count -= 1
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if self.count == 0:
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self.owner = None
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if self.waiters:
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self.waiters -= 1
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self.wakeup.release()
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def __repr__(self):
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return "_ModuleLock(%r) at %d" % (self.name, id(self))
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class _DummyModuleLock:
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"""A simple _ModuleLock equivalent for Python builds without
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multi-threading support."""
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def __init__(self, name):
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self.name = name
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self.count = 0
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def acquire(self):
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self.count += 1
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return True
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def release(self):
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if self.count == 0:
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raise RuntimeError("cannot release un-acquired lock")
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self.count -= 1
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def __repr__(self):
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return "_DummyModuleLock(%r) at %d" % (self.name, id(self))
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# The following two functions are for consumption by Python/import.c.
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def _get_module_lock(name):
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"""Get or create the module lock for a given module name.
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Should only be called with the import lock taken."""
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lock = None
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if name in _module_locks:
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lock = _module_locks[name]()
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if lock is None:
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if _thread is None:
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lock = _DummyModuleLock(name)
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else:
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lock = _ModuleLock(name)
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def cb(_):
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del _module_locks[name]
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_module_locks[name] = _weakref.ref(lock, cb)
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return lock
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def _lock_unlock_module(name):
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"""Release the global import lock, and acquires then release the
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module lock for a given module name.
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This is used to ensure a module is completely initialized, in the
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event it is being imported by another thread.
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Should only be called with the import lock taken."""
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lock = _get_module_lock(name)
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_imp.release_lock()
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try:
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lock.acquire()
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except _DeadlockError:
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# Concurrent circular import, we'll accept a partially initialized
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# module object.
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pass
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else:
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lock.release()
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# Finder/loader utility code ##################################################
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_PYCACHE = '__pycache__'
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SOURCE_SUFFIXES = ['.py'] # _setup() adds .pyw as needed.
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DEBUG_BYTECODE_SUFFIXES = ['.pyc']
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OPTIMIZED_BYTECODE_SUFFIXES = ['.pyo']
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if __debug__:
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BYTECODE_SUFFIXES = DEBUG_BYTECODE_SUFFIXES
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else:
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BYTECODE_SUFFIXES = OPTIMIZED_BYTECODE_SUFFIXES
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def cache_from_source(path, debug_override=None):
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"""Given the path to a .py file, return the path to its .pyc/.pyo file.
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The .py file does not need to exist; this simply returns the path to the
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.pyc/.pyo file calculated as if the .py file were imported. The extension
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will be .pyc unless __debug__ is not defined, then it will be .pyo.
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If debug_override is not None, then it must be a boolean and is taken as
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the value of __debug__ instead.
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"""
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debug = __debug__ if debug_override is None else debug_override
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if debug:
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suffixes = DEBUG_BYTECODE_SUFFIXES
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else:
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suffixes = OPTIMIZED_BYTECODE_SUFFIXES
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head, tail = _path_split(path)
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base_filename, sep, _ = tail.partition('.')
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filename = ''.join([base_filename, sep, _TAG, suffixes[0]])
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return _path_join(head, _PYCACHE, filename)
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def _verbose_message(message, *args):
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"""Print the message to stderr if -v/PYTHONVERBOSE is turned on."""
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if sys.flags.verbose:
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if not message.startswith(('#', 'import ')):
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message = '# ' + message
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print(message.format(*args), file=sys.stderr)
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def set_package(fxn):
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"""Set __package__ on the returned module."""
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def set_package_wrapper(*args, **kwargs):
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module = fxn(*args, **kwargs)
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if getattr(module, '__package__', None) is None:
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module.__package__ = module.__name__
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if not hasattr(module, '__path__'):
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module.__package__ = module.__package__.rpartition('.')[0]
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return module
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_wrap(set_package_wrapper, fxn)
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return set_package_wrapper
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def set_loader(fxn):
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"""Set __loader__ on the returned module."""
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def set_loader_wrapper(self, *args, **kwargs):
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module = fxn(self, *args, **kwargs)
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if not hasattr(module, '__loader__'):
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module.__loader__ = self
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return module
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_wrap(set_loader_wrapper, fxn)
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return set_loader_wrapper
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def module_for_loader(fxn):
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"""Decorator to handle selecting the proper module for loaders.
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The decorated function is passed the module to use instead of the module
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name. The module passed in to the function is either from sys.modules if
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it already exists or is a new module. If the module is new, then __name__
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is set the first argument to the method, __loader__ is set to self, and
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__package__ is set accordingly (if self.is_package() is defined) will be set
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before it is passed to the decorated function (if self.is_package() does
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not work for the module it will be set post-load).
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If an exception is raised and the decorator created the module it is
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subsequently removed from sys.modules.
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The decorator assumes that the decorated function takes the module name as
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the second argument.
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"""
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def module_for_loader_wrapper(self, fullname, *args, **kwargs):
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module = sys.modules.get(fullname)
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is_reload = module is not None
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if not is_reload:
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# This must be done before open() is called as the 'io' module
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# implicitly imports 'locale' and would otherwise trigger an
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# infinite loop.
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module = new_module(fullname)
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sys.modules[fullname] = module
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module.__loader__ = self
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try:
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is_package = self.is_package(fullname)
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except (ImportError, AttributeError):
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pass
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else:
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if is_package:
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module.__package__ = fullname
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else:
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module.__package__ = fullname.rpartition('.')[0]
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try:
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module.__initializing__ = True
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# If __package__ was not set above, __import__() will do it later.
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return fxn(self, module, *args, **kwargs)
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except:
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if not is_reload:
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del sys.modules[fullname]
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raise
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finally:
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module.__initializing__ = False
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_wrap(module_for_loader_wrapper, fxn)
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return module_for_loader_wrapper
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def _check_name(method):
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"""Decorator to verify that the module being requested matches the one the
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loader can handle.
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The first argument (self) must define _name which the second argument is
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compared against. If the comparison fails then ImportError is raised.
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"""
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def _check_name_wrapper(self, name=None, *args, **kwargs):
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if name is None:
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name = self.name
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elif self.name != name:
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raise ImportError("loader cannot handle %s" % name, name=name)
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return method(self, name, *args, **kwargs)
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_wrap(_check_name_wrapper, method)
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return _check_name_wrapper
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def _requires_builtin(fxn):
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"""Decorator to verify the named module is built-in."""
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def _requires_builtin_wrapper(self, fullname):
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if fullname not in sys.builtin_module_names:
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raise ImportError("{} is not a built-in module".format(fullname),
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name=fullname)
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return fxn(self, fullname)
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_wrap(_requires_builtin_wrapper, fxn)
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return _requires_builtin_wrapper
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def _requires_frozen(fxn):
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"""Decorator to verify the named module is frozen."""
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def _requires_frozen_wrapper(self, fullname):
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if not _imp.is_frozen(fullname):
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raise ImportError("{} is not a frozen module".format(fullname),
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name=fullname)
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return fxn(self, fullname)
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_wrap(_requires_frozen_wrapper, fxn)
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return _requires_frozen_wrapper
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# Loaders #####################################################################
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class BuiltinImporter:
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"""Meta path import for built-in modules.
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All methods are either class or static methods to avoid the need to
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instantiate the class.
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"""
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@classmethod
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def module_repr(cls, module):
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return "<module '{}' (built-in)>".format(module.__name__)
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@classmethod
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def find_module(cls, fullname, path=None):
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"""Find the built-in module.
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If 'path' is ever specified then the search is considered a failure.
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"""
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if path is not None:
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return None
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return cls if _imp.is_builtin(fullname) else None
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|
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@classmethod
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@set_package
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@set_loader
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@_requires_builtin
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def load_module(cls, fullname):
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"""Load a built-in module."""
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is_reload = fullname in sys.modules
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try:
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return _imp.init_builtin(fullname)
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except:
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if not is_reload and fullname in sys.modules:
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del sys.modules[fullname]
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raise
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@classmethod
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@_requires_builtin
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def get_code(cls, fullname):
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"""Return None as built-in modules do not have code objects."""
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return None
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@classmethod
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@_requires_builtin
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def get_source(cls, fullname):
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"""Return None as built-in modules do not have source code."""
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return None
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@classmethod
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@_requires_builtin
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def is_package(cls, fullname):
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"""Return False as built-in modules are never packages."""
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return False
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|
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|
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class FrozenImporter:
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"""Meta path import for frozen modules.
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All methods are either class or static methods to avoid the need to
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instantiate the class.
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"""
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|
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@classmethod
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|
def module_repr(cls, m):
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return "<module '{}' (frozen)>".format(m.__name__)
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|
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@classmethod
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def find_module(cls, fullname, path=None):
|
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"""Find a frozen module."""
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return cls if _imp.is_frozen(fullname) else None
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|
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@classmethod
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@set_package
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@set_loader
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@_requires_frozen
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def load_module(cls, fullname):
|
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"""Load a frozen module."""
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is_reload = fullname in sys.modules
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try:
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m = cls._exec_module(fullname)
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# Let our own module_repr() method produce a suitable repr.
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|
del m.__file__
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return m
|
|
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)
|
|
|
|
@classmethod
|
|
def _exec_module(cls, fullname):
|
|
"""Helper for load_module, allowing to isolate easily (when
|
|
looking at a traceback) whether an error comes from executing
|
|
an imported module's code."""
|
|
return _imp.init_frozen(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 = _path_split(self.get_filename(fullname))[1]
|
|
filename_base = filename.rsplit('.', 1)[0]
|
|
tail_name = fullname.rpartition('.')[2]
|
|
return filename_base == '__init__' and tail_name != '__init__'
|
|
|
|
def _bytes_from_bytecode(self, fullname, data, bytecode_path, source_stats):
|
|
"""Return the marshalled bytes from bytecode, verifying the magic
|
|
number, timestamp and source size along the way.
|
|
|
|
If source_stats is None then skip the timestamp check.
|
|
|
|
"""
|
|
magic = data[:4]
|
|
raw_timestamp = data[4:8]
|
|
raw_size = data[8:12]
|
|
if magic != _MAGIC_NUMBER:
|
|
msg = 'bad magic number in {!r}: {!r}'.format(fullname, magic)
|
|
raise ImportError(msg, name=fullname, path=bytecode_path)
|
|
elif len(raw_timestamp) != 4:
|
|
message = 'bad timestamp in {}'.format(fullname)
|
|
_verbose_message(message)
|
|
raise EOFError(message)
|
|
elif len(raw_size) != 4:
|
|
message = 'bad size in {}'.format(fullname)
|
|
_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 {}'.format(fullname)
|
|
_verbose_message(message)
|
|
raise ImportError(message, name=fullname,
|
|
path=bytecode_path)
|
|
try:
|
|
source_size = source_stats['size'] & 0xFFFFFFFF
|
|
except KeyError:
|
|
pass
|
|
else:
|
|
if _r_long(raw_size) != source_size:
|
|
raise ImportError(
|
|
"bytecode is stale for {}".format(fullname),
|
|
name=fullname, path=bytecode_path)
|
|
# Can't return the code object as errors from marshal loading need to
|
|
# propagate even when source is available.
|
|
return data[12:]
|
|
|
|
@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__ = cache_from_source(module.__file__)
|
|
else:
|
|
module.__cached__ = module.__file__
|
|
module.__package__ = name
|
|
if self.is_package(name):
|
|
module.__path__ = [_path_split(module.__file__)[0]]
|
|
else:
|
|
module.__package__ = module.__package__.rpartition('.')[0]
|
|
module.__loader__ = self
|
|
self._exec_module(code_object, module.__dict__)
|
|
return module
|
|
|
|
def _exec_module(self, code_object, module_dict):
|
|
"""Helper for _load_module, allowing to isolate easily (when
|
|
looking at a traceback) whether an error comes from executing
|
|
an imported module's code."""
|
|
exec(code_object, module_dict)
|
|
|
|
|
|
class SourceLoader(_LoaderBasics):
|
|
|
|
def path_mtime(self, path):
|
|
"""Optional method that returns the modification time (an int) for the
|
|
specified path, where path is a str.
|
|
"""
|
|
raise NotImplementedError
|
|
|
|
def path_stats(self, path):
|
|
"""Optional method returning a metadata dict for the specified path
|
|
to by the path (str).
|
|
Possible keys:
|
|
- 'mtime' (mandatory) is the numeric timestamp of last source
|
|
code modification;
|
|
- 'size' (optional) is the size in bytes of the source code.
|
|
|
|
Implementing this method allows the loader to read bytecode files.
|
|
"""
|
|
return {'mtime': self.path_mtime(path)}
|
|
|
|
def set_data(self, path, data):
|
|
"""Optional method which writes data (bytes) to a file path (a str).
|
|
|
|
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()",
|
|
name=fullname)
|
|
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_stats to be implemented. To write
|
|
bytecode, set_data must also be implemented.
|
|
|
|
"""
|
|
source_path = self.get_filename(fullname)
|
|
bytecode_path = cache_from_source(source_path)
|
|
source_mtime = None
|
|
if bytecode_path is not None:
|
|
try:
|
|
st = self.path_stats(source_path)
|
|
except NotImplementedError:
|
|
pass
|
|
else:
|
|
source_mtime = int(st['mtime'])
|
|
try:
|
|
data = self.get_data(bytecode_path)
|
|
except IOError:
|
|
pass
|
|
else:
|
|
try:
|
|
bytes_data = self._bytes_from_bytecode(fullname, data,
|
|
bytecode_path,
|
|
st)
|
|
except (ImportError, EOFError):
|
|
pass
|
|
else:
|
|
_verbose_message('{} matches {}', bytecode_path,
|
|
source_path)
|
|
found = marshal.loads(bytes_data)
|
|
if isinstance(found, _code_type):
|
|
_imp._fix_co_filename(found, source_path)
|
|
_verbose_message('code object from {}',
|
|
bytecode_path)
|
|
return found
|
|
else:
|
|
msg = "Non-code object in {}"
|
|
raise ImportError(msg.format(bytecode_path),
|
|
name=fullname, path=bytecode_path)
|
|
source_bytes = self.get_data(source_path)
|
|
code_object = compile(source_bytes, source_path, 'exec',
|
|
dont_inherit=True)
|
|
_verbose_message('code object from {}', source_path)
|
|
if (not sys.dont_write_bytecode and bytecode_path is not None and
|
|
source_mtime is not None):
|
|
data = bytearray(_MAGIC_NUMBER)
|
|
data.extend(_w_long(source_mtime))
|
|
data.extend(_w_long(len(source_bytes)))
|
|
data.extend(marshal.dumps(code_object))
|
|
try:
|
|
self.set_data(bytecode_path, data)
|
|
_verbose_message('wrote {!r}', bytecode_path)
|
|
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 load_module(self, fullname):
|
|
"""Load a module from a file."""
|
|
# Issue #14857: Avoid the zero-argument form so the implementation
|
|
# of that form can be updated without breaking the frozen module
|
|
return super(FileLoader, self).load_module(fullname)
|
|
|
|
@_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 _io.FileIO(path, 'r') as file:
|
|
return file.read()
|
|
|
|
|
|
class SourceFileLoader(FileLoader, SourceLoader):
|
|
|
|
"""Concrete implementation of SourceLoader using the file system."""
|
|
|
|
def path_stats(self, path):
|
|
"""Return the metadat for the path."""
|
|
st = _os.stat(path)
|
|
return {'mtime': st.st_mtime, 'size': st.st_size}
|
|
|
|
def set_data(self, path, data):
|
|
"""Write bytes data to a file."""
|
|
parent, filename = _path_split(path)
|
|
path_parts = []
|
|
# Figure out what directories are missing.
|
|
while parent and not _path_isdir(parent):
|
|
parent, part = _path_split(parent)
|
|
path_parts.append(part)
|
|
# Create needed directories.
|
|
for part in reversed(path_parts):
|
|
parent = _path_join(parent, part)
|
|
try:
|
|
_os.mkdir(parent)
|
|
except FileExistsError:
|
|
# Probably another Python process already created the dir.
|
|
continue
|
|
except PermissionError:
|
|
# If can't get proper access, then just forget about writing
|
|
# the data.
|
|
return
|
|
try:
|
|
_write_atomic(path, data)
|
|
_verbose_message('created {!r}', path)
|
|
except (PermissionError, FileExistsError):
|
|
# Don't worry if you can't write bytecode or someone is writing
|
|
# it at the same time.
|
|
pass
|
|
|
|
|
|
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, path, None)
|
|
found = marshal.loads(bytes_data)
|
|
if isinstance(found, _code_type):
|
|
_verbose_message('code object from {!r}', path)
|
|
return found
|
|
else:
|
|
raise ImportError("Non-code object in {}".format(path),
|
|
name=fullname, path=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):
|
|
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:
|
|
module = self._exec_module(fullname, self.path)
|
|
_verbose_message('extension module loaded from {!r}', self.path)
|
|
return module
|
|
except:
|
|
if not is_reload and fullname in sys.modules:
|
|
del sys.modules[fullname]
|
|
raise
|
|
|
|
def is_package(self, fullname):
|
|
"""Return False as an extension module can never be a package."""
|
|
return False
|
|
|
|
def get_code(self, fullname):
|
|
"""Return None as an extension module cannot create a code object."""
|
|
return None
|
|
|
|
def get_source(self, fullname):
|
|
"""Return None as extension modules have no source code."""
|
|
return None
|
|
|
|
def _exec_module(self, fullname, path):
|
|
"""Helper for load_module, allowing to isolate easily (when
|
|
looking at a traceback) whether an error comes from executing
|
|
an imported module's code."""
|
|
return _imp.load_dynamic(fullname, path)
|
|
|
|
|
|
class _NamespacePath:
|
|
"""Represents a namespace package's path. It uses the module name
|
|
to find its parent module, and from there it looks up the parent's
|
|
__path__. When this changes, the module's own path is recomputed,
|
|
using path_finder. For top-leve modules, the parent module's path
|
|
is sys.path."""
|
|
|
|
def __init__(self, name, path, path_finder):
|
|
self._name = name
|
|
self._path = path
|
|
self._last_parent_path = tuple(self._get_parent_path())
|
|
self._path_finder = path_finder
|
|
|
|
def _find_parent_path_names(self):
|
|
"""Returns a tuple of (parent-module-name, parent-path-attr-name)"""
|
|
parent, dot, me = self._name.rpartition('.')
|
|
if dot == '':
|
|
# This is a top-level module. sys.path contains the parent path.
|
|
return 'sys', 'path'
|
|
# Not a top-level module. parent-module.__path__ contains the
|
|
# parent path.
|
|
return parent, '__path__'
|
|
|
|
def _get_parent_path(self):
|
|
parent_module_name, path_attr_name = self._find_parent_path_names()
|
|
return getattr(sys.modules[parent_module_name], path_attr_name)
|
|
|
|
def _recalculate(self):
|
|
# If the parent's path has changed, recalculate _path
|
|
parent_path = tuple(self._get_parent_path()) # Make a copy
|
|
if parent_path != self._last_parent_path:
|
|
loader, new_path = self._path_finder(self._name, parent_path)
|
|
# Note that no changes are made if a loader is returned, but we
|
|
# do remember the new parent path
|
|
if loader is None:
|
|
self._path = new_path
|
|
self._last_parent_path = parent_path # Save the copy
|
|
return self._path
|
|
|
|
def __iter__(self):
|
|
return iter(self._recalculate())
|
|
|
|
def __len__(self):
|
|
return len(self._recalculate())
|
|
|
|
def __repr__(self):
|
|
return "_NamespacePath({!r})".format(self._path)
|
|
|
|
def __contains__(self, item):
|
|
return item in self._recalculate()
|
|
|
|
def append(self, item):
|
|
self._path.append(item)
|
|
|
|
|
|
class NamespaceLoader:
|
|
def __init__(self, name, path, path_finder):
|
|
self._path = _NamespacePath(name, path, path_finder)
|
|
|
|
@classmethod
|
|
def module_repr(cls, module):
|
|
return "<module '{}' (namespace)>".format(module.__name__)
|
|
|
|
@module_for_loader
|
|
def load_module(self, module):
|
|
"""Load a namespace module."""
|
|
_verbose_message('namespace module loaded with path {!r}', self._path)
|
|
module.__path__ = self._path
|
|
return module
|
|
|
|
|
|
# Finders #####################################################################
|
|
|
|
class PathFinder:
|
|
|
|
"""Meta path finder for sys.(path|path_hooks|path_importer_cache)."""
|
|
|
|
@classmethod
|
|
def _path_hooks(cls, path):
|
|
"""Search sequence of hooks for a finder for 'path'.
|
|
|
|
If 'hooks' is false then use sys.path_hooks.
|
|
|
|
"""
|
|
if not sys.path_hooks:
|
|
_warnings.warn('sys.path_hooks is empty', ImportWarning)
|
|
for hook in sys.path_hooks:
|
|
try:
|
|
return hook(path)
|
|
except ImportError:
|
|
continue
|
|
else:
|
|
return None
|
|
|
|
@classmethod
|
|
def _path_importer_cache(cls, path):
|
|
"""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 no finder is available, store None.
|
|
|
|
"""
|
|
if path == '':
|
|
path = '.'
|
|
try:
|
|
finder = sys.path_importer_cache[path]
|
|
except KeyError:
|
|
finder = cls._path_hooks(path)
|
|
sys.path_importer_cache[path] = finder
|
|
return finder
|
|
|
|
@classmethod
|
|
def _get_loader(cls, fullname, path):
|
|
"""Find the loader or namespace_path for this module/package name."""
|
|
# If this ends up being a namespace package, namespace_path is
|
|
# the list of paths that will become its __path__
|
|
namespace_path = []
|
|
for entry in path:
|
|
finder = cls._path_importer_cache(entry)
|
|
if finder is not None:
|
|
if hasattr(finder, 'find_loader'):
|
|
loader, portions = finder.find_loader(fullname)
|
|
else:
|
|
loader = finder.find_module(fullname)
|
|
portions = []
|
|
if loader is not None:
|
|
# We found a loader: return it immediately.
|
|
return (loader, namespace_path)
|
|
# This is possibly part of a namespace package.
|
|
# Remember these path entries (if any) for when we
|
|
# create a namespace package, and continue iterating
|
|
# on path.
|
|
namespace_path.extend(portions)
|
|
else:
|
|
return (None, namespace_path)
|
|
|
|
@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 path is None:
|
|
path = sys.path
|
|
loader, namespace_path = cls._get_loader(fullname, path)
|
|
if loader is not None:
|
|
return loader
|
|
else:
|
|
if namespace_path:
|
|
# We found at least one namespace path. Return a
|
|
# loader which can create the namespace package.
|
|
return NamespaceLoader(fullname, namespace_path, cls._get_loader)
|
|
else:
|
|
return None
|
|
|
|
|
|
class FileFinder:
|
|
|
|
"""File-based finder.
|
|
|
|
Interactions with the file system are cached for performance, being
|
|
refreshed when the directory the finder is handling has been modified.
|
|
|
|
"""
|
|
|
|
def __init__(self, path, *details):
|
|
"""Initialize with the path to search on and a variable number of
|
|
3-tuples containing the loader, file suffixes the loader recognizes,
|
|
and a boolean of whether the loader handles packages."""
|
|
packages = []
|
|
modules = []
|
|
for loader, suffixes, supports_packages in details:
|
|
modules.extend((suffix, loader) for suffix in suffixes)
|
|
if supports_packages:
|
|
packages.extend((suffix, loader) for suffix in suffixes)
|
|
self.packages = packages
|
|
self.modules = modules
|
|
# Base (directory) path
|
|
self.path = path or '.'
|
|
self._path_mtime = -1
|
|
self._path_cache = set()
|
|
self._relaxed_path_cache = set()
|
|
|
|
def invalidate_caches(self):
|
|
"""Invalidate the directory mtime."""
|
|
self._path_mtime = -1
|
|
|
|
def find_module(self, fullname):
|
|
"""Try to find a loader for the specified module."""
|
|
# 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)
|
|
assert len(portions) in [0, 1]
|
|
if loader is None and len(portions):
|
|
msg = "Not importing directory {}: missing __init__"
|
|
_warnings.warn(msg.format(portions[0]), ImportWarning)
|
|
return loader
|
|
|
|
def find_loader(self, fullname):
|
|
"""Try to find a loader for the specified module, or the namespace
|
|
package portions. Returns (loader, list-of-portions)."""
|
|
is_namespace = False
|
|
tail_module = fullname.rpartition('.')[2]
|
|
try:
|
|
mtime = _os.stat(self.path).st_mtime
|
|
except OSError:
|
|
mtime = -1
|
|
if mtime != self._path_mtime:
|
|
self._fill_cache()
|
|
self._path_mtime = mtime
|
|
# tail_module keeps the original casing, for __file__ and friends
|
|
if _relax_case():
|
|
cache = self._relaxed_path_cache
|
|
cache_module = tail_module.lower()
|
|
else:
|
|
cache = self._path_cache
|
|
cache_module = tail_module
|
|
# Check if the module is the name of a directory (and thus a package).
|
|
if cache_module in cache:
|
|
base_path = _path_join(self.path, tail_module)
|
|
if _path_isdir(base_path):
|
|
for suffix, loader in self.packages:
|
|
init_filename = '__init__' + suffix
|
|
full_path = _path_join(base_path, init_filename)
|
|
if _path_isfile(full_path):
|
|
return (loader(fullname, full_path), [base_path])
|
|
else:
|
|
# A namespace package, return the path if we don't also
|
|
# find a module in the next section.
|
|
is_namespace = True
|
|
# Check for a file w/ a proper suffix exists.
|
|
for suffix, loader in self.modules:
|
|
if cache_module + suffix in cache:
|
|
full_path = _path_join(self.path, tail_module + suffix)
|
|
if _path_isfile(full_path):
|
|
return (loader(fullname, full_path), [])
|
|
if is_namespace:
|
|
return (None, [base_path])
|
|
return (None, [])
|
|
|
|
def _fill_cache(self):
|
|
"""Fill the cache of potential modules and packages for this directory."""
|
|
path = self.path
|
|
contents = _os.listdir(path)
|
|
# We store two cached versions, to handle runtime changes of the
|
|
# PYTHONCASEOK environment variable.
|
|
if not sys.platform.startswith('win'):
|
|
self._path_cache = set(contents)
|
|
else:
|
|
# Windows users can import modules with case-insensitive file
|
|
# suffixes (for legacy reasons). Make the suffix lowercase here
|
|
# so it's done once instead of for every import. This is safe as
|
|
# the specified suffixes to check against are always specified in a
|
|
# case-sensitive manner.
|
|
lower_suffix_contents = set()
|
|
for item in contents:
|
|
name, dot, suffix = item.partition('.')
|
|
if dot:
|
|
new_name = '{}.{}'.format(name, suffix.lower())
|
|
else:
|
|
new_name = name
|
|
lower_suffix_contents.add(new_name)
|
|
self._path_cache = lower_suffix_contents
|
|
if sys.platform.startswith(_CASE_INSENSITIVE_PLATFORMS):
|
|
self._relaxed_path_cache = set(fn.lower() for fn in contents)
|
|
|
|
@classmethod
|
|
def path_hook(cls, *loader_details):
|
|
"""A class method which returns a closure to use on sys.path_hook
|
|
which will return an instance using the specified loaders and the path
|
|
called on the closure.
|
|
|
|
If the path called on the closure is not a directory, ImportError is
|
|
raised.
|
|
|
|
"""
|
|
def path_hook_for_FileFinder(path):
|
|
"""Path hook for importlib.machinery.FileFinder."""
|
|
if not _path_isdir(path):
|
|
raise ImportError("only directories are supported", path=path)
|
|
return cls(path, *loader_details)
|
|
|
|
return path_hook_for_FileFinder
|
|
|
|
def __repr__(self):
|
|
return "FileFinder(%r)" % (self.path,)
|
|
|
|
|
|
# Import itself ###############################################################
|
|
|
|
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()
|
|
|
|
|
|
def _resolve_name(name, package, level):
|
|
"""Resolve a relative module name to an absolute one."""
|
|
bits = package.rsplit('.', level - 1)
|
|
if len(bits) < level:
|
|
raise ValueError('attempted relative import beyond top-level package')
|
|
base = bits[0]
|
|
return '{}.{}'.format(base, name) if name else base
|
|
|
|
|
|
def _find_module(name, path):
|
|
"""Find a module's loader."""
|
|
if not sys.meta_path:
|
|
_warnings.warn('sys.meta_path is empty', ImportWarning)
|
|
for finder in sys.meta_path:
|
|
with _ImportLockContext():
|
|
loader = finder.find_module(name, path)
|
|
if loader is not None:
|
|
# The parent import may have already imported this module.
|
|
if name not in sys.modules:
|
|
return loader
|
|
else:
|
|
return sys.modules[name].__loader__
|
|
else:
|
|
return None
|
|
|
|
|
|
def _sanity_check(name, package, level):
|
|
"""Verify arguments are "sane"."""
|
|
if not isinstance(name, str):
|
|
raise TypeError("module name must be str, not {}".format(type(name)))
|
|
if level < 0:
|
|
raise ValueError('level must be >= 0')
|
|
if package:
|
|
if not isinstance(package, str):
|
|
raise TypeError("__package__ not set to a string")
|
|
elif package not in sys.modules:
|
|
msg = ("Parent module {!r} not loaded, cannot perform relative "
|
|
"import")
|
|
raise SystemError(msg.format(package))
|
|
if not name and level == 0:
|
|
raise ValueError("Empty module name")
|
|
|
|
|
|
_ERR_MSG = 'No module named {!r}'
|
|
|
|
def _find_and_load_unlocked(name, import_):
|
|
path = None
|
|
parent = name.rpartition('.')[0]
|
|
if parent:
|
|
if parent not in sys.modules:
|
|
import_(parent)
|
|
# Crazy side-effects!
|
|
if name in sys.modules:
|
|
return sys.modules[name]
|
|
# Backwards-compatibility; be nicer to skip the dict lookup.
|
|
parent_module = sys.modules[parent]
|
|
try:
|
|
path = parent_module.__path__
|
|
except AttributeError:
|
|
msg = (_ERR_MSG + '; {} is not a package').format(name, parent)
|
|
raise ImportError(msg, name=name)
|
|
loader = _find_module(name, path)
|
|
if loader is None:
|
|
raise ImportError(_ERR_MSG.format(name), name=name)
|
|
elif name not in sys.modules:
|
|
# The parent import may have already imported this module.
|
|
loader.load_module(name)
|
|
_verbose_message('import {!r} # {!r}', name, loader)
|
|
# Backwards-compatibility; be nicer to skip the dict lookup.
|
|
module = sys.modules[name]
|
|
if parent:
|
|
# Set the module as an attribute on its parent.
|
|
parent_module = sys.modules[parent]
|
|
setattr(parent_module, name.rpartition('.')[2], module)
|
|
# Set __package__ if the loader did not.
|
|
if getattr(module, '__package__', None) is None:
|
|
try:
|
|
module.__package__ = module.__name__
|
|
if not hasattr(module, '__path__'):
|
|
module.__package__ = module.__package__.rpartition('.')[0]
|
|
except AttributeError:
|
|
pass
|
|
# Set loader if need be.
|
|
if not hasattr(module, '__loader__'):
|
|
try:
|
|
module.__loader__ = loader
|
|
except AttributeError:
|
|
pass
|
|
return module
|
|
|
|
|
|
def _find_and_load(name, import_):
|
|
"""Find and load the module, and release the import lock."""
|
|
try:
|
|
lock = _get_module_lock(name)
|
|
finally:
|
|
_imp.release_lock()
|
|
lock.acquire()
|
|
try:
|
|
return _find_and_load_unlocked(name, import_)
|
|
finally:
|
|
lock.release()
|
|
|
|
|
|
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 setting __package__ if
|
|
the loader did not.
|
|
|
|
"""
|
|
_sanity_check(name, package, level)
|
|
if level > 0:
|
|
name = _resolve_name(name, package, level)
|
|
_imp.acquire_lock()
|
|
if name not in sys.modules:
|
|
return _find_and_load(name, _gcd_import)
|
|
module = sys.modules[name]
|
|
if module is None:
|
|
_imp.release_lock()
|
|
message = ("import of {} halted; "
|
|
"None in sys.modules".format(name))
|
|
raise ImportError(message, name=name)
|
|
_lock_unlock_module(name)
|
|
return module
|
|
|
|
|
|
def _handle_fromlist(module, fromlist, import_):
|
|
"""Figure out what __import__ should return.
|
|
|
|
The import_ parameter is a callable which takes the name of module to
|
|
import. It is required to decouple the function from assuming importlib's
|
|
import implementation is desired.
|
|
|
|
"""
|
|
# The hell that is fromlist ...
|
|
# 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 fromlist:
|
|
if not hasattr(module, x):
|
|
try:
|
|
import_('{}.{}'.format(module.__name__, x))
|
|
except ImportError:
|
|
pass
|
|
return module
|
|
|
|
|
|
def _calc___package__(globals):
|
|
"""Calculate what __package__ should be.
|
|
|
|
__package__ is not guaranteed to be defined or could be set to None
|
|
to represent that its proper value is unknown.
|
|
|
|
"""
|
|
package = globals.get('__package__')
|
|
if package is None:
|
|
package = globals['__name__']
|
|
if '__path__' not in globals:
|
|
package = package.rpartition('.')[0]
|
|
return package
|
|
|
|
|
|
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 level == 0:
|
|
module = _gcd_import(name)
|
|
else:
|
|
package = _calc___package__(globals)
|
|
module = _gcd_import(name, package, level)
|
|
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 _gcd_import(name.partition('.')[0])
|
|
elif not name:
|
|
return module
|
|
else:
|
|
cut_off = len(name) - len(name.partition('.')[0])
|
|
return sys.modules[module.__name__[:len(module.__name__)-cut_off]]
|
|
else:
|
|
return _handle_fromlist(module, fromlist, _gcd_import)
|
|
|
|
|
|
_MAGIC_NUMBER = None # Set in _setup()
|
|
_TAG = None # Set in _setup()
|
|
|
|
|
|
def _setup(sys_module, _imp_module):
|
|
"""Setup importlib by importing needed built-in modules and injecting them
|
|
into the global namespace.
|
|
|
|
As sys is needed for sys.modules access and _imp is needed to load built-in
|
|
modules, those two modules must be explicitly passed in.
|
|
|
|
"""
|
|
global _imp, sys
|
|
_imp = _imp_module
|
|
sys = sys_module
|
|
|
|
for module in (_imp, sys):
|
|
if not hasattr(module, '__loader__'):
|
|
module.__loader__ = BuiltinImporter
|
|
|
|
self_module = sys.modules[__name__]
|
|
for builtin_name in ('_io', '_warnings', 'builtins', 'marshal'):
|
|
if builtin_name not in sys.modules:
|
|
builtin_module = BuiltinImporter.load_module(builtin_name)
|
|
else:
|
|
builtin_module = sys.modules[builtin_name]
|
|
setattr(self_module, builtin_name, builtin_module)
|
|
|
|
os_details = ('posix', ['/']), ('nt', ['\\', '/']), ('os2', ['\\', '/'])
|
|
for builtin_os, path_separators in os_details:
|
|
# Assumption made in _path_join()
|
|
assert all(len(sep) == 1 for sep in path_separators)
|
|
path_sep = path_separators[0]
|
|
if builtin_os in sys.modules:
|
|
os_module = sys.modules[builtin_os]
|
|
break
|
|
else:
|
|
try:
|
|
os_module = BuiltinImporter.load_module(builtin_os)
|
|
# TODO: rip out os2 code after 3.3 is released as per PEP 11
|
|
if builtin_os == 'os2' and 'EMX GCC' in sys.version:
|
|
path_sep = path_separators[1]
|
|
break
|
|
except ImportError:
|
|
continue
|
|
else:
|
|
raise ImportError('importlib requires posix or nt')
|
|
|
|
try:
|
|
thread_module = BuiltinImporter.load_module('_thread')
|
|
except ImportError:
|
|
# Python was built without threads
|
|
thread_module = None
|
|
weakref_module = BuiltinImporter.load_module('_weakref')
|
|
|
|
setattr(self_module, '_os', os_module)
|
|
setattr(self_module, '_thread', thread_module)
|
|
setattr(self_module, '_weakref', weakref_module)
|
|
setattr(self_module, 'path_sep', path_sep)
|
|
setattr(self_module, 'path_separators', set(path_separators))
|
|
# Constants
|
|
setattr(self_module, '_relax_case', _make_relax_case())
|
|
setattr(self_module, '_MAGIC_NUMBER', _imp_module.get_magic())
|
|
setattr(self_module, '_TAG', sys.implementation.cache_tag)
|
|
if builtin_os == 'nt':
|
|
SOURCE_SUFFIXES.append('.pyw')
|
|
|
|
|
|
def _install(sys_module, _imp_module):
|
|
"""Install importlib as the implementation of import."""
|
|
_setup(sys_module, _imp_module)
|
|
extensions = ExtensionFileLoader, _imp_module.extension_suffixes(), False
|
|
source = SourceFileLoader, SOURCE_SUFFIXES, True
|
|
bytecode = SourcelessFileLoader, BYTECODE_SUFFIXES, True
|
|
supported_loaders = [extensions, source, bytecode]
|
|
sys.path_hooks.extend([FileFinder.path_hook(*supported_loaders)])
|
|
sys.meta_path.extend([BuiltinImporter, FrozenImporter, PathFinder])
|