diff options
| -rw-r--r-- | Lib/pkgutil.py | 264 | ||||
| -rwxr-xr-x | Lib/runpy.py | 355 |
2 files changed, 280 insertions, 339 deletions
diff --git a/Lib/pkgutil.py b/Lib/pkgutil.py index fbd708acc2..d4fe6ca27b 100644 --- a/Lib/pkgutil.py +++ b/Lib/pkgutil.py @@ -1,7 +1,271 @@ """Utilities to support packages.""" +# NOTE: This module must remain compatible with Python 2.3, as it is shared +# by setuptools for distribution with Python 2.3 and up. + import os import sys +import imp +import os.path +from types import ModuleType + +__all__ = [ + 'get_importer', 'iter_importers', 'get_loader', 'find_loader', + 'ImpImporter', 'ImpLoader', 'read_code', 'extend_path', +] + +def read_code(stream): + # This helper is needed in order for the PEP 302 emulation to + # correctly handle compiled files + import marshal + + magic = stream.read(4) + if magic != imp.get_magic(): + return None + + stream.read(4) # Skip timestamp + return marshal.load(stream) + + +class ImpImporter: + """PEP 302 Importer that wraps Python's "classic" import algorithm + + ImpImporter(dirname) produces a PEP 302 importer that searches that + directory. ImpImporter(None) produces a PEP 302 importer that searches + the current sys.path, plus any modules that are frozen or built-in. + + Note that ImpImporter does not currently support being used by placement + on sys.meta_path. + """ + + def __init__(self, path=None): + self.path = path + + def find_module(self, fullname, path=None): + # Note: we ignore 'path' argument since it is only used via meta_path + subname = fullname.split(".")[-1] + if subname != fullname and self.path is None: + return None + if self.path is None: + path = None + else: + path = [self.path] + try: + file, filename, etc = imp.find_module(subname, path) + except ImportError: + return None + return ImpLoader(fullname, file, filename, etc) + + +class ImpLoader: + """PEP 302 Loader that wraps Python's "classic" import algorithm + """ + code = source = None + + def __init__(self, fullname, file, filename, etc): + self.file = file + self.filename = filename + self.fullname = fullname + self.etc = etc + + def load_module(self, fullname): + self._reopen() + try: + mod = imp.load_module(fullname, self.file, self.filename, self.etc) + finally: + if self.file: + self.file.close() + # Note: we don't set __loader__ because we want the module to look + # normal; i.e. this is just a wrapper for standard import machinery + return mod + + def get_data(self, pathname): + return open(pathname, "rb").read() + + def _reopen(self): + if self.file and self.file.closed: + if mod_type==imp.PY_SOURCE: + self.file = open(self.filename, 'rU') + elif mod_type in (imp.PY_COMPILED, imp.C_EXTENSION): + self.file = open(self.filename, 'rb') + + def _fix_name(self, fullname): + if fullname is None: + fullname = self.fullname + elif fullname != self.fullname: + raise ImportError("Loader for module %s cannot handle " + "module %s" % (self.fullname, fullname)) + return fullname + + def is_package(self): + return self.etc[2]==imp.PKG_DIRECTORY + + def get_code(self, fullname=None): + fullname = self._fix_name(fullname) + if self.code is None: + mod_type = self.etc[2] + if mod_type==imp.PY_SOURCE: + source = self.get_source(fullname) + self.code = compile(source, self.filename, 'exec') + elif mod_type==imp.PY_COMPILED: + self._reopen() + try: + self.code = read_code(self.file) + finally: + self.file.close() + elif mod_type==imp.PKG_DIRECTORY: + self.code = self._get_delegate().get_code() + return self.code + + def get_source(self, fullname=None): + fullname = self._fix_name(fullname) + if self.source is None: + mod_type = self.etc[2] + if mod_type==imp.PY_SOURCE: + self._reopen() + try: + self.source = self.file.read() + finally: + self.file.close() + elif mod_type==imp.PY_COMPILED: + if os.path.exists(self.filename[:-1]): + f = open(self.filename[:-1], 'rU') + self.source = f.read() + f.close() + elif mod_type==imp.PKG_DIRECTORY: + self.source = self._get_delegate().get_source() + return self.source + + def _get_delegate(self): + return ImpImporter(self.filename).find_module('__init__') + + def get_filename(self, fullname=None): + fullname = self._fix_name(fullname) + mod_type = self.etc[2] + if self.etc[2]==imp.PKG_DIRECTORY: + return self._get_delegate().get_filename() + elif self.etc[2] in (imp.PY_SOURCE, imp.PY_COMPILED, imp.C_EXTENSION): + return self.filename + return None + + +def get_importer(path_item): + """Retrieve a PEP 302 importer for the given path item + + The returned importer is cached in sys.path_importer_cache + if it was newly created by a path hook. + + If there is no importer, a wrapper around the basic import + machinery is returned. This wrapper is never inserted into + the importer cache (None is inserted instead). + + The cache (or part of it) can be cleared manually if a + rescan of sys.path_hooks is necessary. + """ + try: + importer = sys.path_importer_cache[path_item] + except KeyError: + for path_hook in sys.path_hooks: + try: + importer = path_hook(path_item) + break + except ImportError: + pass + else: + importer = None + sys.path_importer_cache.setdefault(path_item,importer) + + if importer is None: + try: + importer = ImpImporter(path_item) + except ImportError: + pass + return importer + + +def iter_importers(fullname): + """Yield PEP 302 importers for the given module name + + If fullname contains a '.', the importers will be for the package + containing fullname, otherwise they will be importers for sys.meta_path, + sys.path, and Python's "classic" import machinery, in that order. If + the named module is in a package, that package is imported as a side + effect of invoking this function. + + Non PEP 302 mechanisms (e.g. the Windows registry) used by the + standard import machinery to find files in alternative locations + are partially supported, but are searched AFTER sys.path. Normally, + these locations are searched BEFORE sys.path, preventing sys.path + entries from shadowing them. + + For this to cause a visible difference in behaviour, there must + be a module or package name that is accessible via both sys.path + and one of the non PEP 302 file system mechanisms. In this case, + the emulation will find the former version, while the builtin + import mechanism will find the latter. + + Items of the following types can be affected by this discrepancy: + imp.C_EXTENSION, imp.PY_SOURCE, imp.PY_COMPILED, imp.PKG_DIRECTORY + """ + if fullname.startswith('.'): + raise ImportError("Relative module names not supported") + if '.' in fullname: + # Get the containing package's __path__ + pkg = '.'.join(fullname.split('.')[:-1]) + if pkg not in sys.modules: + __import__(pkg) + path = getattr(sys.modules[pkg],'__path__',None) or [] + else: + for importer in sys.meta_path: + yield importer + path = sys.path + for item in path: + yield get_importer(item) + if '.' not in fullname: + yield ImpImporter() + + +def get_loader(module_or_name): + """Get a PEP 302 "loader" object for module_or_name + + If the module or package is accessible via the normal import + mechanism, a wrapper around the relevant part of that machinery + is returned. Returns None if the module cannot be found or imported. + If the named module is not already imported, its containing package + (if any) is imported, in order to establish the package __path__. + + This function uses iter_importers(), and is thus subject to the same + limitations regarding platform-specific special import locations such + as the Windows registry. + """ + if module_or_name in sys.modules: + module_or_name = sys.modules[module_or_name] + if isinstance(module_or_name, ModuleType): + module = module_or_name + loader = getattr(module,'__loader__',None) + if loader is not None: + return loader + fullname = module.__name__ + else: + fullname = module_or_name + return find_loader(fullname) + + +def find_loader(fullname): + """Find a PEP 302 "loader" object for fullname + + If fullname contains dots, path must be the containing package's __path__. + Returns None if the module cannot be found or imported. This function uses + iter_importers(), and is thus subject to the same limitations regarding + platform-specific special import locations such as the Windows registry. + """ + for importer in iter_importers(fullname): + loader = importer.find_module(fullname) + if loader is not None: + return loader + + return None + def extend_path(path, name): """Extend a package's path. diff --git a/Lib/runpy.py b/Lib/runpy.py index 0af9a503a6..8290dfea70 100755 --- a/Lib/runpy.py +++ b/Lib/runpy.py @@ -11,349 +11,15 @@ importers when locating support scripts as well as when importing modules. import sys import imp +try: + from imp import get_loader +except ImportError: + from pkgutil import get_loader __all__ = [ "run_module", ] -try: - _get_loader = imp.get_loader -except AttributeError: - # get_loader() is not provided by the imp module, so emulate it - # as best we can using the PEP 302 import machinery exposed since - # Python 2.3. The emulation isn't perfect, but the differences - # in the way names are shadowed shouldn't matter in practice. - import os.path - import marshal # Handle compiled Python files - - # This helper is needed in order for the PEP 302 emulation to - # correctly handle compiled files - def _read_compiled_file(compiled_file): - magic = compiled_file.read(4) - if magic != imp.get_magic(): - return None - try: - compiled_file.read(4) # Skip timestamp - return marshal.load(compiled_file) - except Exception: - return None - - class _AbsoluteImporter(object): - """PEP 302 importer wrapper for top level import machinery""" - def find_module(self, mod_name, path=None): - if path is not None: - return None - try: - file, filename, mod_info = imp.find_module(mod_name) - except ImportError: - return None - suffix, mode, mod_type = mod_info - if mod_type == imp.PY_SOURCE: - loader = _SourceFileLoader(mod_name, file, - filename, mod_info) - elif mod_type == imp.PY_COMPILED: - loader = _CompiledFileLoader(mod_name, file, - filename, mod_info) - elif mod_type == imp.PKG_DIRECTORY: - loader = _PackageDirLoader(mod_name, file, - filename, mod_info) - elif mod_type == imp.C_EXTENSION: - loader = _FileSystemLoader(mod_name, file, - filename, mod_info) - else: - loader = _BasicLoader(mod_name, file, - filename, mod_info) - return loader - - - class _FileSystemImporter(object): - """PEP 302 importer wrapper for filesystem based imports""" - def __init__(self, path_item=None): - if path_item is not None: - if path_item != '' and not os.path.isdir(path_item): - raise ImportError("%s is not a directory" % path_item) - self.path_dir = path_item - else: - raise ImportError("Filesystem importer requires " - "a directory name") - - def find_module(self, mod_name, path=None): - if path is not None: - return None - path_dir = self.path_dir - if path_dir == '': - path_dir = os.getcwd() - sub_name = mod_name.rsplit(".", 1)[-1] - try: - file, filename, mod_info = imp.find_module(sub_name, - [path_dir]) - except ImportError: - return None - if not filename.startswith(path_dir): - return None - suffix, mode, mod_type = mod_info - if mod_type == imp.PY_SOURCE: - loader = _SourceFileLoader(mod_name, file, - filename, mod_info) - elif mod_type == imp.PY_COMPILED: - loader = _CompiledFileLoader(mod_name, file, - filename, mod_info) - elif mod_type == imp.PKG_DIRECTORY: - loader = _PackageDirLoader(mod_name, file, - filename, mod_info) - elif mod_type == imp.C_EXTENSION: - loader = _FileSystemLoader(mod_name, file, - filename, mod_info) - else: - loader = _BasicLoader(mod_name, file, - filename, mod_info) - return loader - - - class _BasicLoader(object): - """PEP 302 loader wrapper for top level import machinery""" - def __init__(self, mod_name, file, filename, mod_info): - self.mod_name = mod_name - self.file = file - self.filename = filename - self.mod_info = mod_info - - def _fix_name(self, mod_name): - if mod_name is None: - mod_name = self.mod_name - elif mod_name != self.mod_name: - raise ImportError("Loader for module %s cannot handle " - "module %s" % (self.mod_name, mod_name)) - return mod_name - - def load_module(self, mod_name=None): - mod_name = self._fix_name(mod_name) - mod = imp.load_module(mod_name, self.file, - self.filename, self.mod_info) - mod.__loader__ = self # for introspection - return mod - - def get_code(self, mod_name=None): - return None - - def get_source(self, mod_name=None): - return None - - def is_package(self, mod_name=None): - return False - - def close(self): - if self.file: - self.file.close() - - def __del__(self): - self.close() - - - class _FileSystemLoader(_BasicLoader): - """PEP 302 loader wrapper for filesystem based imports""" - def get_code(self, mod_name=None): - mod_name = self._fix_name(mod_name) - return self._get_code(mod_name) - - def get_data(self, pathname): - return open(pathname, "rb").read() - - def get_filename(self, mod_name=None): - mod_name = self._fix_name(mod_name) - return self._get_filename(mod_name) - - def get_source(self, mod_name=None): - mod_name = self._fix_name(mod_name) - return self._get_source(mod_name) - - def is_package(self, mod_name=None): - mod_name = self._fix_name(mod_name) - return self._is_package(mod_name) - - def _get_code(self, mod_name): - return None - - def _get_filename(self, mod_name): - return self.filename - - def _get_source(self, mod_name): - return None - - def _is_package(self, mod_name): - return False - - class _PackageDirLoader(_FileSystemLoader): - """PEP 302 loader wrapper for PKG_DIRECTORY directories""" - def _is_package(self, mod_name): - return True - - - class _SourceFileLoader(_FileSystemLoader): - """PEP 302 loader wrapper for PY_SOURCE modules""" - def _get_code(self, mod_name): - return compile(self._get_source(mod_name), - self.filename, 'exec') - - def _get_source(self, mod_name): - f = self.file - f.seek(0) - return f.read() - - - class _CompiledFileLoader(_FileSystemLoader): - """PEP 302 loader wrapper for PY_COMPILED modules""" - def _get_code(self, mod_name): - f = self.file - f.seek(0) - return _read_compiled_file(f) - - - def _get_importer(path_item): - """Retrieve a PEP 302 importer for the given path item - - The returned importer is cached in sys.path_importer_cache - if it was newly created by a path hook. - - If there is no importer, a wrapper around the basic import - machinery is returned. This wrapper is never inserted into - the importer cache (None is inserted instead). - - The cache (or part of it) can be cleared manually if a - rescan of sys.path_hooks is necessary. - """ - try: - importer = sys.path_importer_cache[path_item] - except KeyError: - for path_hook in sys.path_hooks: - try: - importer = path_hook(path_item) - break - except ImportError: - pass - else: - importer = None - sys.path_importer_cache[path_item] = importer - if importer is None: - try: - importer = _FileSystemImporter(path_item) - except ImportError: - pass - return importer - - - def _get_path_loader(mod_name, path=None): - """Retrieve a PEP 302 loader using a path importer""" - if path is None: - path = sys.path - absolute_loader = _AbsoluteImporter().find_module(mod_name) - if isinstance(absolute_loader, _FileSystemLoader): - # Found in filesystem, so scan path hooks - # before accepting this one as the right one - loader = None - else: - # Not found in filesystem, so use top-level loader - loader = absolute_loader - else: - loader = absolute_loader = None - if loader is None: - for path_item in path: - importer = _get_importer(path_item) - if importer is not None: - loader = importer.find_module(mod_name) - if loader is not None: - # Found a loader for our module - break - else: - # No path hook found, so accept the top level loader - loader = absolute_loader - return loader - - def _get_package(pkg_name): - """Retrieve a named package""" - pkg = __import__(pkg_name) - sub_pkg_names = pkg_name.split(".") - for sub_pkg in sub_pkg_names[1:]: - pkg = getattr(pkg, sub_pkg) - return pkg - - def _get_loader(mod_name, path=None): - """Retrieve a PEP 302 loader for the given module or package - - If the module or package is accessible via the normal import - mechanism, a wrapper around the relevant part of that machinery - is returned. - - Non PEP 302 mechanisms (e.g. the Windows registry) used by the - standard import machinery to find files in alternative locations - are partially supported, but are searched AFTER sys.path. Normally, - these locations are searched BEFORE sys.path, preventing sys.path - entries from shadowing them. - For this to cause a visible difference in behaviour, there must - be a module or package name that is accessible via both sys.path - and one of the non PEP 302 file system mechanisms. In this case, - the emulation will find the former version, while the builtin - import mechanism will find the latter. - Items of the following types can be affected by this discrepancy: - imp.C_EXTENSION - imp.PY_SOURCE - imp.PY_COMPILED - imp.PKG_DIRECTORY - """ - try: - loader = sys.modules[mod_name].__loader__ - except (KeyError, AttributeError): - loader = None - if loader is None: - imp.acquire_lock() - try: - # Module not in sys.modules, or uses an unhooked loader - parts = mod_name.rsplit(".", 1) - if len(parts) == 2: - # Sub package, so use parent package's path - pkg_name, sub_name = parts - if pkg_name and pkg_name[0] != '.': - if path is not None: - raise ImportError("Path argument must be None " - "for a dotted module name") - pkg = _get_package(pkg_name) - try: - path = pkg.__path__ - except AttributeError: - raise ImportError(pkg_name + - " is not a package") - else: - raise ImportError("Relative import syntax is not " - "supported by _get_loader()") - else: - # Top level module, so stick with default path - sub_name = mod_name - - for importer in sys.meta_path: - loader = importer.find_module(mod_name, path) - if loader is not None: - # Found a metahook to handle the module - break - else: - # Handling via the standard path mechanism - loader = _get_path_loader(mod_name, path) - finally: - imp.release_lock() - return loader - - -# This helper is needed due to a missing component in the PEP 302 -# loader protocol (specifically, "get_filename" is non-standard) -def _get_filename(loader, mod_name): - try: - get_filename = loader.get_filename - except AttributeError: - return None - else: - return get_filename(mod_name) - -# ------------------------------------------------------------ -# Done with the import machinery emulation, on with the code! def _run_code(code, run_globals, init_globals, mod_name, mod_fname, mod_loader): @@ -399,13 +65,24 @@ def _run_module_code(code, init_globals=None, mod_name, mod_fname, mod_loader) +# This helper is needed due to a missing component in the PEP 302 +# loader protocol (specifically, "get_filename" is non-standard) +def _get_filename(loader, mod_name): + try: + get_filename = loader.get_filename + except AttributeError: + return None + else: + return get_filename(mod_name) + + def run_module(mod_name, init_globals=None, run_name=None, alter_sys=False): """Execute a module's code without importing it Returns the resulting top level namespace dictionary """ - loader = _get_loader(mod_name) + loader = get_loader(mod_name) if loader is None: raise ImportError("No module named " + mod_name) code = loader.get_code(mod_name) |