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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. # XXX Make sure all public names have no single leading underscore and all # others do. # 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 # TODO: Expose from marshal def _w_long(x): """Convert a 32-bit integer to little-endian. XXX Temporary until marshal's long functions are exposed. """ x = int(x) int_bytes = [] int_bytes.append(x & 0xFF) int_bytes.append((x >> 8) & 0xFF) int_bytes.append((x >> 16) & 0xFF) int_bytes.append((x >> 24) & 0xFF) return bytearray(int_bytes) # TODO: Expose from marshal def _r_long(int_bytes): """Convert 4 bytes in little-endian to an integer. XXX Temporary until marshal's long function are exposed. """ x = int_bytes[0] x |= int_bytes[1] << 8 x |= int_bytes[2] << 16 x |= int_bytes[3] << 24 return x def _path_join(*path_parts): """Replacement for os.path.join().""" new_parts = [] for part in path_parts: if not part: continue new_parts.append(part) if part[-1] not in path_separators: new_parts.append(path_sep) return ''.join(new_parts[:-1]) # Drop superfluous path separator. def _path_split(path): """Replacement for os.path.split().""" for x in reversed(path): if x in path_separators: sep = x break else: sep = path_sep front, _, tail = path.rpartition(sep) return front, tail def _path_is_mode_type(path, mode): """Test whether the path is the specified mode type.""" try: stat_info = _os.stat(path) except OSError: return False return (stat_info.st_mode & 0o170000) == mode # XXX Could also expose Modules/getpath.c:isfile() def _path_isfile(path): """Replacement for os.path.isfile.""" return _path_is_mode_type(path, 0o100000) # XXX Could also expose Modules/getpath.c:isdir() def _path_isdir(path): """Replacement for os.path.isdir.""" if not path: path = _os.getcwd() return _path_is_mode_type(path, 0o040000) def _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__) _code_type = type(_wrap.__code__) def new_module(name): """Create a new module. The module is not entered into sys.modules. """ return type(_io)(name) # 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 %d" % (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 %d" % (self.name, id(self)) # 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 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) 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). """ _RAW_MAGIC_NUMBER = 3230 | ord('\r') << 16 | ord('\n') << 24 _MAGIC_BYTES = bytes(_RAW_MAGIC_NUMBER >> n & 0xff for n in range(0, 25, 8)) _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 _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 set_package(fxn): """Set __package__ on the returned module.""" def set_package_wrapper(*args, **kwargs): module = fxn(*args, **kwargs) if getattr(module, '__package__', None) is None: module.__package__ = module.__name__ if not hasattr(module, '__path__'): module.__package__ = module.__package__.rpartition('.')[0] return module _wrap(set_package_wrapper, fxn) return set_package_wrapper def set_loader(fxn): """Set __loader__ on the returned module.""" def set_loader_wrapper(self, *args, **kwargs): module = fxn(self, *args, **kwargs) if not hasattr(module, '__loader__'): module.__loader__ = self return module _wrap(set_loader_wrapper, fxn) return set_loader_wrapper def module_for_loader(fxn): """Decorator to handle selecting the proper module for loaders. The decorated function is passed the module to use instead of the module name. The module passed in to the function is either from sys.modules if it already exists or is a new module. If the module is new, then __name__ is set the first argument to the method, __loader__ is set to self, and __package__ is set accordingly (if self.is_package() is defined) will be set before it is passed to the decorated function (if self.is_package() does not work for the module it will be set post-load). If an exception is raised and the decorator created the module it is subsequently removed from sys.modules. The decorator assumes that the decorated function takes the module name as the second argument. """ def module_for_loader_wrapper(self, fullname, *args, **kwargs): module = sys.modules.get(fullname) is_reload = module is not None if not is_reload: # This must be done before open() is called as the 'io' module # implicitly imports 'locale' and would otherwise trigger an # infinite loop. module = new_module(fullname) # This must be done before putting the module in sys.modules # (otherwise an optimization shortcut in import.c becomes wrong) module.__initializing__ = True sys.modules[fullname] = module module.__loader__ = self try: is_package = self.is_package(fullname) except (ImportError, AttributeError): pass else: if is_package: module.__package__ = fullname else: module.__package__ = fullname.rpartition('.')[0] else: module.__initializing__ = True try: # If __package__ was not set above, __import__() will do it later. return fxn(self, module, *args, **kwargs) except: if not is_reload: del sys.modules[fullname] raise finally: module.__initializing__ = False _wrap(module_for_loader_wrapper, fxn) return module_for_loader_wrapper 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("{} 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("{} 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().""" # 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 # Loaders ##################################################################### class BuiltinImporter: """Meta path import for built-in modules. All methods are either class or static methods to avoid the need to instantiate the class. """ @classmethod def module_repr(cls, module): return "<module '{}' (built-in)>".format(module.__name__) @classmethod def find_module(cls, fullname, path=None): """Find the built-in module. If 'path' is ever specified then the search is considered a failure. """ if path is not None: return None return cls if _imp.is_builtin(fullname) else None @classmethod @set_package @set_loader @_requires_builtin def load_module(cls, fullname): """Load a built-in module.""" is_reload = fullname in sys.modules try: return _call_with_frames_removed(_imp.init_builtin, fullname) except: if not is_reload and fullname in sys.modules: del sys.modules[fullname] raise @classmethod @_requires_builtin def get_code(cls, fullname): """Return None as built-in modules do not have code objects.""" return None @classmethod @_requires_builtin def get_source(cls, fullname): """Return None as built-in modules do not have source code.""" return None @classmethod @_requires_builtin def is_package(cls, fullname): """Return False as built-in modules are never packages.""" return False class FrozenImporter: """Meta path import for frozen modules. All methods are either class or static methods to avoid the need to instantiate the class. """ @classmethod def module_repr(cls, m): return "<module '{}' (frozen)>".format(m.__name__) @classmethod def find_module(cls, fullname, path=None): """Find a frozen module.""" return cls if _imp.is_frozen(fullname) else None @classmethod @set_package @set_loader @_requires_frozen def load_module(cls, fullname): """Load a frozen module.""" is_reload = fullname in sys.modules try: m = _call_with_frames_removed(_imp.init_frozen, fullname) # Let our own module_repr() method produce a suitable repr. del m.__file__ 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 True if the frozen module is a package.""" return _imp.is_frozen_package(fullname) class WindowsRegistryFinder: """Meta path finder for modules declared in the Windows registry. """ REGISTRY_KEY = ( "Software\\Python\\PythonCore\\{sys_version}" "\\Modules\\{fullname}") REGISTRY_KEY_DEBUG = ( "Software\\Python\\PythonCore\\{sys_version}" "\\Modules\\{fullname}\\Debug") DEBUG_BUILD = False # Changed in _setup() @classmethod def _open_registry(cls, key): try: return _winreg.OpenKey(_winreg.HKEY_CURRENT_USER, key) except WindowsError: return _winreg.OpenKey(_winreg.HKEY_LOCAL_MACHINE, key) @classmethod def _search_registry(cls, fullname): if cls.DEBUG_BUILD: registry_key = cls.REGISTRY_KEY_DEBUG else: registry_key = cls.REGISTRY_KEY key = registry_key.format(fullname=fullname, sys_version=sys.version[:3]) try: with cls._open_registry(key) as hkey: filepath = _winreg.QueryValue(hkey, "") except WindowsError: return None return filepath @classmethod def find_module(cls, fullname, path=None): """Find module named in the registry.""" filepath = cls._search_registry(fullname) if filepath is None: return None try: _os.stat(filepath) except OSError: return None for loader, suffixes in _get_supported_file_loaders(): if filepath.endswith(tuple(suffixes)): return loader(fullname, filepath) 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_BYTES: msg = 'bad magic number in {!r}: {!r}'.format(fullname, magic) _verbose_message(msg) 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: try: module.__cached__ = cache_from_source(module.__file__) except NotImplementedError: module.__cached__ = 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 _call_with_frames_removed(exec, code_object, module.__dict__) return module 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 _cache_bytecode(self, source_path, cache_path, data): """Optional method which writes data (bytes) to a file path (a str). Implementing this method allows for the writing of bytecode files. The source path is needed in order to correctly transfer permissions """ # For backwards compatibility, we delegate to set_data() return self.set_data(cache_path, data) 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 as exc: raise ImportError("source not available through get_data()", name=fullname) from exc readsource = _io.BytesIO(source_bytes).readline try: encoding = tokenize.detect_encoding(readsource) except SyntaxError as exc: raise ImportError("Failed to detect encoding", name=fullname) from exc newline_decoder = _io.IncrementalNewlineDecoder(None, True) try: return newline_decoder.decode(source_bytes.decode(encoding[0])) except UnicodeDecodeError as exc: raise ImportError("Failed to decode source file", name=fullname) from exc 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) source_mtime = None try: bytecode_path = cache_from_source(source_path) except NotImplementedError: bytecode_path = None else: 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 = _call_with_frames_removed(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_BYTES) data.extend(_w_long(source_mtime)) data.extend(_w_long(len(source_bytes))) data.extend(marshal.dumps(code_object)) try: self._cache_bytecode(source_path, 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 metadata for the path.""" st = _os.stat(path) return {'mtime': st.st_mtime, 'size': st.st_size} def _cache_bytecode(self, source_path, bytecode_path, data): # Adapt between the two APIs try: mode = _os.stat(source_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 self.set_data(bytecode_path, data, _mode=mode) def set_data(self, path, data, *, _mode=0o666): """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 OSError as exc: # Could be a permission error, read-only filesystem: just forget # about writing the data. _verbose_message('could not create {!r}: {!r}', parent, exc) return try: _write_atomic(path, data, _mode) _verbose_message('created {!r}', path) except OSError as exc: # Same as above: just don't write the bytecode. _verbose_message('could not create {!r}: {!r}', path, exc) 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 # Filled in by _setup(). EXTENSION_SUFFIXES = [] 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 = _call_with_frames_removed(_imp.load_dynamic, fullname, self.path) _verbose_message('extension module loaded from {!r}', self.path) if self.is_package(fullname) and not hasattr(module, '__path__'): module.__path__ = [_path_split(self.path)[0]] return module except: if not is_reload and fullname in sys.modules: del sys.modules[fullname] raise def is_package(self, fullname): """Return True if the extension module is a package.""" file_name = _path_split(self.path)[1] return any(file_name == '__init__' + suffix for suffix in EXTENSION_SUFFIXES) 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 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-level 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 and package __path__ attributes.""" @classmethod def invalidate_caches(cls): """Call the invalidate_caches() method on all path entry finders stored in sys.path_importer_caches (where implemented).""" for finder in sys.path_importer_cache.values(): if hasattr(finder, 'invalidate_caches'): finder.invalidate_caches() @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 entry from sys.path_importer_cache. If the path entry 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: if not isinstance(entry, (str, bytes)): continue 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, *loader_details): """Initialize with the path to search on and a variable number of 2-tuples containing the loader and the file suffixes the loader recognizes.""" loaders = [] for loader, suffixes in loader_details: loaders.extend((suffix, loader) for suffix in suffixes) self._loaders = loaders # 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 find_module = _find_module_shim 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._loaders: 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._loaders: full_path = _path_join(self.path, tail_module + suffix) _verbose_message('trying {}'.format(full_path), verbosity=2) if cache_module + suffix in cache: if _path_isfile(full_path): return (loader(fullname, full_path), []) if is_namespace: _verbose_message('possible namespace for {}'.format(base_path)) return (None, [base_path]) return (None, []) def _fill_cache(self): """Fill the cache of potential modules and packages for this directory.""" path = self.path try: contents = _os.listdir(path) except (FileNotFoundError, PermissionError, NotADirectoryError): # Directory has either been removed, turned into a file, or made # unreadable. contents = [] # 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: _call_with_frames_removed(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: exc = ImportError(_ERR_MSG.format(name), name=name) # TODO(brett): switch to a proper ModuleNotFound exception in Python # 3.4. exc._not_found = True raise exc 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: fromlist = list(fromlist) fromlist.remove('*') if hasattr(module, '__all__'): fromlist.extend(module.__all__) for x in fromlist: if not hasattr(module, x): from_name = '{}.{}'.format(module.__name__, x) try: _call_with_frames_removed(import_, from_name) except ImportError as exc: # Backwards-compatibility dictates we ignore failed # imports triggered by fromlist for modules that don't # exist. # TODO(brett): In Python 3.4, have import raise # ModuleNotFound and catch that. if getattr(exc, '_not_found', False): if exc.name == from_name: continue raise 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 _get_supported_file_loaders(): """Returns a list of file-based module loaders. Each item is a tuple (loader, suffixes). """ extensions = ExtensionFileLoader, _imp.extension_suffixes() source = SourceFileLoader, SOURCE_SUFFIXES bytecode = SourcelessFileLoader, BYTECODE_SUFFIXES return [extensions, source, bytecode] def __import__(name, globals=None, locals=None, 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: globals_ = globals if globals is not None 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: # Figure out where to slice the module's name up to the first dot # in 'name'. cut_off = len(name) - len(name.partition('.')[0]) # Slice end needs to be positive to alleviate need to special-case # when ``'.' not in name``. return sys.modules[module.__name__[:len(module.__name__)-cut_off]] else: return _handle_fromlist(module, fromlist, _gcd_import) 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, BYTECODE_SUFFIXES _imp = _imp_module sys = sys_module if sys.flags.optimize: BYTECODE_SUFFIXES = OPTIMIZED_BYTECODE_SUFFIXES else: BYTECODE_SUFFIXES = DEBUG_BYTECODE_SUFFIXES module_type = type(sys) for name, module in sys.modules.items(): if isinstance(module, module_type): if not hasattr(module, '__loader__'): if name in sys.builtin_module_names: module.__loader__ = BuiltinImporter elif _imp.is_frozen(name): module.__loader__ = FrozenImporter 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') if builtin_os == 'nt': winreg_module = BuiltinImporter.load_module('winreg') setattr(self_module, '_winreg', winreg_module) 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()) EXTENSION_SUFFIXES.extend(_imp.extension_suffixes()) if builtin_os == 'nt': SOURCE_SUFFIXES.append('.pyw') if '_d.pyd' in EXTENSION_SUFFIXES: WindowsRegistryFinder.DEBUG_BUILD = True def _install(sys_module, _imp_module): """Install importlib as the implementation of import.""" _setup(sys_module, _imp_module) supported_loaders = _get_supported_file_loaders() sys.path_hooks.extend([FileFinder.path_hook(*supported_loaders)]) sys.meta_path.append(BuiltinImporter) sys.meta_path.append(FrozenImporter) if _os.__name__ == 'nt': sys.meta_path.append(WindowsRegistryFinder) sys.meta_path.append(PathFinder)