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Diffstat (limited to 'Lib/pkgutil.py')
| -rw-r--r-- | Lib/pkgutil.py | 425 |
1 files changed, 425 insertions, 0 deletions
diff --git a/Lib/pkgutil.py b/Lib/pkgutil.py index fbd708a..7316892 100644 --- a/Lib/pkgutil.py +++ b/Lib/pkgutil.py @@ -1,7 +1,432 @@ """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', + 'walk_packages', 'iter_modules', + '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) + + +def simplegeneric(func): + """Make a trivial single-dispatch generic function""" + registry = {} + def wrapper(*args,**kw): + ob = args[0] + try: + cls = ob.__class__ + except AttributeError: + cls = type(ob) + try: + mro = cls.__mro__ + except AttributeError: + try: + class cls(cls,object): pass + mro = cls.__mro__[1:] + except TypeError: + mro = object, # must be an ExtensionClass or some such :( + for t in mro: + if t in registry: + return registry[t](*args,**kw) + else: + return func(*args,**kw) + try: + wrapper.__name__ = func.__name__ + except (TypeError,AttributeError): + pass # Python 2.3 doesn't allow functions to be renamed + + def register(typ, func=None): + if func is None: + return lambda f: register(typ, f) + registry[typ] = func + return func + + wrapper.__dict__ = func.__dict__ + wrapper.__doc__ = func.__doc__ + wrapper.register = register + return wrapper + + +def walk_packages(path=None, prefix='', onerror=None): + """Yield submodule names+loaders recursively, for path or sys.path""" + + def seen(p,m={}): + if p in m: return True + m[p] = True + + for importer, name, ispkg in iter_modules(path, prefix): + yield importer, name, ispkg + + if ispkg: + try: + __import__(name) + except ImportError: + if onerror is not None: + onerror() + else: + path = getattr(sys.modules[name], '__path__', None) or [] + + # don't traverse path items we've seen before + path = [p for p in path if not seen(p)] + + for item in walk_packages(path, name+'.'): + yield item + + +def iter_modules(path=None, prefix=''): + """Yield submodule names+loaders for path or sys.path""" + if path is None: + importers = iter_importers() + else: + importers = map(get_importer, path) + + yielded = {} + for i in importers: + for name, ispkg in iter_importer_modules(i, prefix): + if name not in yielded: + yielded[name] = 1 + yield i, name, ispkg + + +#@simplegeneric +def iter_importer_modules(importer, prefix=''): + if not hasattr(importer,'iter_modules'): + return [] + return importer.iter_modules(prefix) + +iter_importer_modules = simplegeneric(iter_importer_modules) + + +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 = [os.path.realpath(self.path)] + try: + file, filename, etc = imp.find_module(subname, path) + except ImportError: + return None + return ImpLoader(fullname, file, filename, etc) + + def iter_modules(self, prefix=''): + if self.path is None or not os.path.isdir(self.path): + return + + yielded = {} + import inspect + + filenames = os.listdir(self.path) + filenames.sort() # handle packages before same-named modules + + for fn in filenames: + modname = inspect.getmodulename(fn) + if modname=='__init__' or modname in yielded: + continue + + path = os.path.join(self.path, fn) + ispkg = False + + if not modname and os.path.isdir(path) and '.' not in fn: + modname = fn + for fn in os.listdir(path): + subname = inspect.getmodulename(fn) + if subname=='__init__': + ispkg = True + break + else: + continue # not a package + + if modname and '.' not in modname: + yielded[modname] = 1 + yield prefix + modname, ispkg + + +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, fullname): + fullname = self._fix_name(fullname) + 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 + + +try: + import zipimport + from zipimport import zipimporter + + def iter_zipimport_modules(importer, prefix=''): + dirlist = zipimport._zip_directory_cache[importer.archive].keys() + dirlist.sort() + _prefix = importer.prefix + plen = len(_prefix) + yielded = {} + import inspect + for fn in dirlist: + if not fn.startswith(_prefix): + continue + + fn = fn[plen:].split(os.sep) + + if len(fn)==2 and fn[1].startswith('__init__.py'): + if fn[0] not in yielded: + yielded[fn[0]] = 1 + yield fn[0], True + + if len(fn)!=1: + continue + + modname = inspect.getmodulename(fn[0]) + if modname=='__init__': + continue + + if modname and '.' not in modname and modname not in yielded: + yielded[modname] = 1 + yield prefix + modname, False + + iter_importer_modules.register(zipimporter, iter_zipimport_modules) + +except ImportError: + pass + + +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. |