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3d3cfdb499
imputils Importer._process_result():
remove name from modules dict if exec fails.
This is what all the builtin importers do now, new in 2.4.
520 lines
17 KiB
Python
520 lines
17 KiB
Python
"""Import hook support.
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Consistent use of this module will make it possible to change the
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different mechanisms involved in loading modules independently.
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While the built-in module imp exports interfaces to the built-in
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module searching and loading algorithm, and it is possible to replace
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the built-in function __import__ in order to change the semantics of
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the import statement, until now it has been difficult to combine the
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effect of different __import__ hacks, like loading modules from URLs
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by rimport.py, or restricted execution by rexec.py.
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This module defines three new concepts:
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1) A "file system hooks" class provides an interface to a filesystem.
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One hooks class is defined (Hooks), which uses the interface provided
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by standard modules os and os.path. It should be used as the base
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class for other hooks classes.
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2) A "module loader" class provides an interface to search for a
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module in a search path and to load it. It defines a method which
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searches for a module in a single directory; by overriding this method
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one can redefine the details of the search. If the directory is None,
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built-in and frozen modules are searched instead.
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Two module loader class are defined, both implementing the search
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strategy used by the built-in __import__ function: ModuleLoader uses
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the imp module's find_module interface, while HookableModuleLoader
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uses a file system hooks class to interact with the file system. Both
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use the imp module's load_* interfaces to actually load the module.
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3) A "module importer" class provides an interface to import a
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module, as well as interfaces to reload and unload a module. It also
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provides interfaces to install and uninstall itself instead of the
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default __import__ and reload (and unload) functions.
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One module importer class is defined (ModuleImporter), which uses a
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module loader instance passed in (by default HookableModuleLoader is
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instantiated).
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The classes defined here should be used as base classes for extended
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functionality along those lines.
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If a module importer class supports dotted names, its import_module()
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must return a different value depending on whether it is called on
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behalf of a "from ... import ..." statement or not. (This is caused
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by the way the __import__ hook is used by the Python interpreter.) It
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would also do wise to install a different version of reload().
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"""
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import __builtin__
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import imp
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import os
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import sys
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__all__ = ["BasicModuleLoader","Hooks","ModuleLoader","FancyModuleLoader",
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"BasicModuleImporter","ModuleImporter","install","uninstall"]
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VERBOSE = 0
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from imp import C_EXTENSION, PY_SOURCE, PY_COMPILED
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from imp import C_BUILTIN, PY_FROZEN, PKG_DIRECTORY
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BUILTIN_MODULE = C_BUILTIN
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FROZEN_MODULE = PY_FROZEN
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class _Verbose:
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def __init__(self, verbose = VERBOSE):
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self.verbose = verbose
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def get_verbose(self):
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return self.verbose
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def set_verbose(self, verbose):
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self.verbose = verbose
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# XXX The following is an experimental interface
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def note(self, *args):
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if self.verbose:
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self.message(*args)
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def message(self, format, *args):
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if args:
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print format%args
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else:
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print format
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class BasicModuleLoader(_Verbose):
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"""Basic module loader.
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This provides the same functionality as built-in import. It
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doesn't deal with checking sys.modules -- all it provides is
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find_module() and a load_module(), as well as find_module_in_dir()
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which searches just one directory, and can be overridden by a
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derived class to change the module search algorithm when the basic
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dependency on sys.path is unchanged.
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The interface is a little more convenient than imp's:
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find_module(name, [path]) returns None or 'stuff', and
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load_module(name, stuff) loads the module.
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"""
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def find_module(self, name, path = None):
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if path is None:
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path = [None] + self.default_path()
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for dir in path:
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stuff = self.find_module_in_dir(name, dir)
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if stuff: return stuff
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return None
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def default_path(self):
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return sys.path
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def find_module_in_dir(self, name, dir):
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if dir is None:
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return self.find_builtin_module(name)
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else:
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try:
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return imp.find_module(name, [dir])
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except ImportError:
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return None
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def find_builtin_module(self, name):
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# XXX frozen packages?
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if imp.is_builtin(name):
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return None, '', ('', '', BUILTIN_MODULE)
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if imp.is_frozen(name):
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return None, '', ('', '', FROZEN_MODULE)
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return None
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def load_module(self, name, stuff):
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file, filename, info = stuff
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try:
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return imp.load_module(name, file, filename, info)
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finally:
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if file: file.close()
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class Hooks(_Verbose):
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"""Hooks into the filesystem and interpreter.
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By deriving a subclass you can redefine your filesystem interface,
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e.g. to merge it with the URL space.
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This base class behaves just like the native filesystem.
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"""
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# imp interface
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def get_suffixes(self): return imp.get_suffixes()
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def new_module(self, name): return imp.new_module(name)
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def is_builtin(self, name): return imp.is_builtin(name)
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def init_builtin(self, name): return imp.init_builtin(name)
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def is_frozen(self, name): return imp.is_frozen(name)
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def init_frozen(self, name): return imp.init_frozen(name)
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def get_frozen_object(self, name): return imp.get_frozen_object(name)
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def load_source(self, name, filename, file=None):
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return imp.load_source(name, filename, file)
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def load_compiled(self, name, filename, file=None):
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return imp.load_compiled(name, filename, file)
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def load_dynamic(self, name, filename, file=None):
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return imp.load_dynamic(name, filename, file)
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def load_package(self, name, filename, file=None):
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return imp.load_module(name, file, filename, ("", "", PKG_DIRECTORY))
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def add_module(self, name):
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d = self.modules_dict()
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if name in d: return d[name]
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d[name] = m = self.new_module(name)
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return m
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# sys interface
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def modules_dict(self): return sys.modules
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def default_path(self): return sys.path
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def path_split(self, x): return os.path.split(x)
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def path_join(self, x, y): return os.path.join(x, y)
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def path_isabs(self, x): return os.path.isabs(x)
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# etc.
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def path_exists(self, x): return os.path.exists(x)
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def path_isdir(self, x): return os.path.isdir(x)
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def path_isfile(self, x): return os.path.isfile(x)
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def path_islink(self, x): return os.path.islink(x)
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# etc.
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def openfile(self, *x): return open(*x)
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openfile_error = IOError
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def listdir(self, x): return os.listdir(x)
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listdir_error = os.error
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# etc.
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class ModuleLoader(BasicModuleLoader):
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"""Default module loader; uses file system hooks.
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By defining suitable hooks, you might be able to load modules from
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other sources than the file system, e.g. from compressed or
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encrypted files, tar files or (if you're brave!) URLs.
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"""
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def __init__(self, hooks = None, verbose = VERBOSE):
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BasicModuleLoader.__init__(self, verbose)
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self.hooks = hooks or Hooks(verbose)
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def default_path(self):
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return self.hooks.default_path()
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def modules_dict(self):
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return self.hooks.modules_dict()
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def get_hooks(self):
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return self.hooks
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def set_hooks(self, hooks):
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self.hooks = hooks
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def find_builtin_module(self, name):
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# XXX frozen packages?
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if self.hooks.is_builtin(name):
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return None, '', ('', '', BUILTIN_MODULE)
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if self.hooks.is_frozen(name):
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return None, '', ('', '', FROZEN_MODULE)
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return None
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def find_module_in_dir(self, name, dir, allow_packages=1):
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if dir is None:
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return self.find_builtin_module(name)
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if allow_packages:
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fullname = self.hooks.path_join(dir, name)
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if self.hooks.path_isdir(fullname):
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stuff = self.find_module_in_dir("__init__", fullname, 0)
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if stuff:
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file = stuff[0]
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if file: file.close()
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return None, fullname, ('', '', PKG_DIRECTORY)
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for info in self.hooks.get_suffixes():
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suff, mode, type = info
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fullname = self.hooks.path_join(dir, name+suff)
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try:
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fp = self.hooks.openfile(fullname, mode)
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return fp, fullname, info
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except self.hooks.openfile_error:
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pass
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return None
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def load_module(self, name, stuff):
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file, filename, info = stuff
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(suff, mode, type) = info
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try:
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if type == BUILTIN_MODULE:
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return self.hooks.init_builtin(name)
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if type == FROZEN_MODULE:
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return self.hooks.init_frozen(name)
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if type == C_EXTENSION:
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m = self.hooks.load_dynamic(name, filename, file)
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elif type == PY_SOURCE:
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m = self.hooks.load_source(name, filename, file)
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elif type == PY_COMPILED:
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m = self.hooks.load_compiled(name, filename, file)
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elif type == PKG_DIRECTORY:
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m = self.hooks.load_package(name, filename, file)
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else:
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raise ImportError, "Unrecognized module type (%r) for %s" % \
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(type, name)
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finally:
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if file: file.close()
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m.__file__ = filename
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return m
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class FancyModuleLoader(ModuleLoader):
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"""Fancy module loader -- parses and execs the code itself."""
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def load_module(self, name, stuff):
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file, filename, (suff, mode, type) = stuff
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realfilename = filename
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path = None
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if type == PKG_DIRECTORY:
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initstuff = self.find_module_in_dir("__init__", filename, 0)
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if not initstuff:
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raise ImportError, "No __init__ module in package %s" % name
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initfile, initfilename, initinfo = initstuff
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initsuff, initmode, inittype = initinfo
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if inittype not in (PY_COMPILED, PY_SOURCE):
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if initfile: initfile.close()
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raise ImportError, \
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"Bad type (%r) for __init__ module in package %s" % (
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inittype, name)
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path = [filename]
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file = initfile
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realfilename = initfilename
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type = inittype
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if type == FROZEN_MODULE:
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code = self.hooks.get_frozen_object(name)
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elif type == PY_COMPILED:
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import marshal
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file.seek(8)
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code = marshal.load(file)
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elif type == PY_SOURCE:
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data = file.read()
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code = compile(data, realfilename, 'exec')
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else:
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return ModuleLoader.load_module(self, name, stuff)
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m = self.hooks.add_module(name)
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if path:
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m.__path__ = path
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m.__file__ = filename
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try:
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exec code in m.__dict__
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except:
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d = self.hooks.modules_dict()
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if name in d:
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del d[name]
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raise
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return m
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class BasicModuleImporter(_Verbose):
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"""Basic module importer; uses module loader.
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This provides basic import facilities but no package imports.
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"""
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def __init__(self, loader = None, verbose = VERBOSE):
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_Verbose.__init__(self, verbose)
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self.loader = loader or ModuleLoader(None, verbose)
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self.modules = self.loader.modules_dict()
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def get_loader(self):
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return self.loader
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def set_loader(self, loader):
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self.loader = loader
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def get_hooks(self):
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return self.loader.get_hooks()
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def set_hooks(self, hooks):
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return self.loader.set_hooks(hooks)
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def import_module(self, name, globals={}, locals={}, fromlist=[]):
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name = str(name)
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if name in self.modules:
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return self.modules[name] # Fast path
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stuff = self.loader.find_module(name)
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if not stuff:
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raise ImportError, "No module named %s" % name
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return self.loader.load_module(name, stuff)
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def reload(self, module, path = None):
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name = str(module.__name__)
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stuff = self.loader.find_module(name, path)
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if not stuff:
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raise ImportError, "Module %s not found for reload" % name
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return self.loader.load_module(name, stuff)
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def unload(self, module):
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del self.modules[str(module.__name__)]
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# XXX Should this try to clear the module's namespace?
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def install(self):
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self.save_import_module = __builtin__.__import__
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self.save_reload = __builtin__.reload
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if not hasattr(__builtin__, 'unload'):
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__builtin__.unload = None
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self.save_unload = __builtin__.unload
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__builtin__.__import__ = self.import_module
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__builtin__.reload = self.reload
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__builtin__.unload = self.unload
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def uninstall(self):
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__builtin__.__import__ = self.save_import_module
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__builtin__.reload = self.save_reload
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__builtin__.unload = self.save_unload
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if not __builtin__.unload:
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del __builtin__.unload
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class ModuleImporter(BasicModuleImporter):
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"""A module importer that supports packages."""
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def import_module(self, name, globals=None, locals=None, fromlist=None):
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parent = self.determine_parent(globals)
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q, tail = self.find_head_package(parent, str(name))
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m = self.load_tail(q, tail)
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if not fromlist:
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return q
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if hasattr(m, "__path__"):
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self.ensure_fromlist(m, fromlist)
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return m
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def determine_parent(self, globals):
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if not globals or not "__name__" in globals:
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return None
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pname = globals['__name__']
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if "__path__" in globals:
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parent = self.modules[pname]
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assert globals is parent.__dict__
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return parent
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if '.' in pname:
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i = pname.rfind('.')
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pname = pname[:i]
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parent = self.modules[pname]
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assert parent.__name__ == pname
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return parent
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return None
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def find_head_package(self, parent, name):
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if '.' in name:
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i = name.find('.')
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head = name[:i]
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tail = name[i+1:]
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else:
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head = name
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tail = ""
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if parent:
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qname = "%s.%s" % (parent.__name__, head)
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else:
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qname = head
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q = self.import_it(head, qname, parent)
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if q: return q, tail
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if parent:
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qname = head
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parent = None
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q = self.import_it(head, qname, parent)
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if q: return q, tail
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raise ImportError, "No module named " + qname
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def load_tail(self, q, tail):
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m = q
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while tail:
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i = tail.find('.')
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if i < 0: i = len(tail)
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head, tail = tail[:i], tail[i+1:]
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mname = "%s.%s" % (m.__name__, head)
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m = self.import_it(head, mname, m)
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if not m:
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raise ImportError, "No module named " + mname
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return m
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def ensure_fromlist(self, m, fromlist, recursive=0):
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for sub in fromlist:
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if sub == "*":
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if not recursive:
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try:
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all = m.__all__
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except AttributeError:
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pass
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else:
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self.ensure_fromlist(m, all, 1)
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continue
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if sub != "*" and not hasattr(m, sub):
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subname = "%s.%s" % (m.__name__, sub)
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submod = self.import_it(sub, subname, m)
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if not submod:
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raise ImportError, "No module named " + subname
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def import_it(self, partname, fqname, parent, force_load=0):
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if not partname:
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raise ValueError, "Empty module name"
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if not force_load:
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try:
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return self.modules[fqname]
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except KeyError:
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pass
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try:
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path = parent and parent.__path__
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except AttributeError:
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return None
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partname = str(partname)
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stuff = self.loader.find_module(partname, path)
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if not stuff:
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return None
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fqname = str(fqname)
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m = self.loader.load_module(fqname, stuff)
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if parent:
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setattr(parent, partname, m)
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return m
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def reload(self, module):
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name = str(module.__name__)
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if '.' not in name:
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return self.import_it(name, name, None, force_load=1)
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i = name.rfind('.')
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pname = name[:i]
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parent = self.modules[pname]
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return self.import_it(name[i+1:], name, parent, force_load=1)
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default_importer = None
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current_importer = None
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def install(importer = None):
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global current_importer
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current_importer = importer or default_importer or ModuleImporter()
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current_importer.install()
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def uninstall():
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global current_importer
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current_importer.uninstall()
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