| """Utilities to support packages.""" |
| |
| 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): |
| """Yields (module_loader, name, ispkg) for all modules recursively |
| on path, or, if path is None, all accessible modules. |
| |
| 'path' should be either None or a list of paths to look for |
| modules in. |
| |
| 'prefix' is a string to output on the front of every module name |
| on output. |
| |
| Note that this function must import all *packages* (NOT all |
| modules!) on the given path, in order to access the __path__ |
| attribute to find submodules. |
| |
| 'onerror' is a function which gets called with one argument (the |
| name of the package which was being imported) if any exception |
| occurs while trying to import a package. If no onerror function is |
| supplied, ImportErrors are caught and ignored, while all other |
| exceptions are propagated, terminating the search. |
| |
| Examples: |
| |
| # list all modules python can access |
| walk_packages() |
| |
| # list all submodules of ctypes |
| walk_packages(ctypes.__path__, ctypes.__name__+'.') |
| """ |
| |
| 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(name) |
| except Exception: |
| if onerror is not None: |
| onerror(name) |
| else: |
| raise |
| 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+'.', onerror): |
| yield item |
| |
| |
| def iter_modules(path=None, prefix=''): |
| """Yields (module_loader, name, ispkg) for all submodules on path, |
| or, if path is None, all top-level modules on sys.path. |
| |
| 'path' should be either None or a list of paths to look for |
| modules in. |
| |
| 'prefix' is a string to output on the front of every module name |
| on output. |
| """ |
| |
| 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): |
| with open(pathname, "rb") as file: |
| return file.read() |
| |
| def _reopen(self): |
| if self.file and self.file.closed: |
| mod_type = self.etc[2] |
| 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 = sorted(zipimport._zip_directory_cache[importer.archive]) |
| _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: |
| importer = None |
| 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. |
| |
| Intended use is to place the following code in a package's __init__.py: |
| |
| from pkgutil import extend_path |
| __path__ = extend_path(__path__, __name__) |
| |
| This will add to the package's __path__ all subdirectories of |
| directories on sys.path named after the package. This is useful |
| if one wants to distribute different parts of a single logical |
| package as multiple directories. |
| |
| It also looks for *.pkg files beginning where * matches the name |
| argument. This feature is similar to *.pth files (see site.py), |
| except that it doesn't special-case lines starting with 'import'. |
| A *.pkg file is trusted at face value: apart from checking for |
| duplicates, all entries found in a *.pkg file are added to the |
| path, regardless of whether they are exist the filesystem. (This |
| is a feature.) |
| |
| If the input path is not a list (as is the case for frozen |
| packages) it is returned unchanged. The input path is not |
| modified; an extended copy is returned. Items are only appended |
| to the copy at the end. |
| |
| It is assumed that sys.path is a sequence. Items of sys.path that |
| are not (unicode or 8-bit) strings referring to existing |
| directories are ignored. Unicode items of sys.path that cause |
| errors when used as filenames may cause this function to raise an |
| exception (in line with os.path.isdir() behavior). |
| """ |
| |
| if not isinstance(path, list): |
| # This could happen e.g. when this is called from inside a |
| # frozen package. Return the path unchanged in that case. |
| return path |
| |
| pname = os.path.join(*name.split('.')) # Reconstitute as relative path |
| sname_pkg = name + ".pkg" |
| init_py = "__init__.py" |
| |
| path = path[:] # Start with a copy of the existing path |
| |
| for dir in sys.path: |
| if not isinstance(dir, str) or not os.path.isdir(dir): |
| continue |
| subdir = os.path.join(dir, pname) |
| # XXX This may still add duplicate entries to path on |
| # case-insensitive filesystems |
| initfile = os.path.join(subdir, init_py) |
| if subdir not in path and os.path.isfile(initfile): |
| path.append(subdir) |
| # XXX Is this the right thing for subpackages like zope.app? |
| # It looks for a file named "zope.app.pkg" |
| pkgfile = os.path.join(dir, sname_pkg) |
| if os.path.isfile(pkgfile): |
| try: |
| f = open(pkgfile) |
| except IOError as msg: |
| sys.stderr.write("Can't open %s: %s\n" % |
| (pkgfile, msg)) |
| else: |
| for line in f: |
| line = line.rstrip('\n') |
| if not line or line.startswith('#'): |
| continue |
| path.append(line) # Don't check for existence! |
| f.close() |
| |
| return path |
| |
| def get_data(package, resource): |
| """Get a resource from a package. |
| |
| This is a wrapper round the PEP 302 loader get_data API. The package |
| argument should be the name of a package, in standard module format |
| (foo.bar). The resource argument should be in the form of a relative |
| filename, using '/' as the path separator. The parent directory name '..' |
| is not allowed, and nor is a rooted name (starting with a '/'). |
| |
| The function returns a binary string, which is the contents of the |
| specified resource. |
| |
| For packages located in the filesystem, which have already been imported, |
| this is the rough equivalent of |
| |
| d = os.path.dirname(sys.modules[package].__file__) |
| data = open(os.path.join(d, resource), 'rb').read() |
| |
| If the package cannot be located or loaded, or it uses a PEP 302 loader |
| which does not support get_data(), then None is returned. |
| """ |
| |
| loader = get_loader(package) |
| if loader is None or not hasattr(loader, 'get_data'): |
| return None |
| mod = sys.modules.get(package) or loader.load_module(package) |
| if mod is None or not hasattr(mod, '__file__'): |
| return None |
| |
| # Modify the resource name to be compatible with the loader.get_data |
| # signature - an os.path format "filename" starting with the dirname of |
| # the package's __file__ |
| parts = resource.split('/') |
| parts.insert(0, os.path.dirname(mod.__file__)) |
| resource_name = os.path.join(*parts) |
| return loader.get_data(resource_name) |