+++ /dev/null
-"""New import scheme with package support.
-
-Quick Reference
----------------
-
-- To enable package support, execute "import ni" before importing any
- packages. Importing this module automatically installs the relevant
- import hooks.
-
-- To create a package named spam containing sub-modules ham, bacon and
- eggs, create a directory spam somewhere on Python's module search
- path (i.e. spam's parent directory must be one of the directories in
- sys.path or $PYTHONPATH); then create files ham.py, bacon.py and
- eggs.py inside spam.
-
-- To import module ham from package spam and use function hamneggs()
- from that module, you can either do
-
- import spam.ham # *not* "import spam" !!!
- spam.ham.hamneggs()
-
- or
-
- from spam import ham
- ham.hamneggs()
-
- or
-
- from spam.ham import hamneggs
- hamneggs()
-
-- Importing just "spam" does not do what you expect: it creates an
- empty package named spam if one does not already exist, but it does
- not import spam's submodules. The only submodule that is guaranteed
- to be imported is spam.__init__, if it exists. Note that
- spam.__init__ is a submodule of package spam. It can reference to
- spam's namespace via the '__.' prefix, for instance
-
- __.spam_inited = 1 # Set a package-level variable
-
-
-
-Theory of Operation
--------------------
-
-A Package is a module that can contain other modules. Packages can be
-nested. Package introduce dotted names for modules, like P.Q.M, which
-could correspond to a file P/Q/M.py found somewhere on sys.path. It
-is possible to import a package itself, though this makes little sense
-unless the package contains a module called __init__.
-
-A package has two variables that control the namespace used for
-packages and modules, both initialized to sensible defaults the first
-time the package is referenced.
-
-(1) A package's *module search path*, contained in the per-package
-variable __path__, defines a list of *directories* where submodules or
-subpackages of the package are searched. It is initialized to the
-directory containing the package. Setting this variable to None makes
-the module search path default to sys.path (this is not quite the same
-as setting it to sys.path, since the latter won't track later
-assignments to sys.path).
-
-(2) A package's *import domain*, contained in the per-package variable
-__domain__, defines a list of *packages* that are searched (using
-their respective module search paths) to satisfy imports. It is
-initialized to the list cosisting of the package itself, its parent
-package, its parent's parent, and so on, ending with the root package
-(the nameless package containing all top-level packages and modules,
-whose module search path is None, implying sys.path).
-
-The default domain implements a search algorithm called "expanding
-search". An alternative search algorithm called "explicit search"
-fixes the import search path to contain only the root package,
-requiring the modules in the package to name all imported modules by
-their full name. The convention of using '__' to refer to the current
-package (both as a per-module variable and in module names) can be
-used by packages using explicit search to refer to modules in the same
-package; this combination is known as "explicit-relative search".
-
-The PackageImporter and PackageLoader classes together implement the
-following policies:
-
-- There is a root package, whose name is ''. It cannot be imported
- directly but may be referenced, e.g. by using '__' from a top-level
- module.
-
-- In each module or package, the variable '__' contains a reference to
- the parent package; in the root package, '__' points to itself.
-
-- In the name for imported modules (e.g. M in "import M" or "from M
- import ..."), a leading '__' refers to the current package (i.e.
- the package containing the current module); leading '__.__' and so
- on refer to the current package's parent, and so on. The use of
- '__' elsewhere in the module name is not supported.
-
-- Modules are searched using the "expanding search" algorithm by
- virtue of the default value for __domain__.
-
-- If A.B.C is imported, A is searched using __domain__; then
- subpackage B is searched in A using its __path__, and so on.
-
-- Built-in modules have priority: even if a file sys.py exists in a
- package, "import sys" imports the built-in sys module.
-
-- The same holds for frozen modules, for better or for worse.
-
-- Submodules and subpackages are not automatically loaded when their
- parent packages is loaded.
-
-- The construct "from package import *" is illegal. (It can still be
- used to import names from a module.)
-
-- When "from package import module1, module2, ..." is used, those
- modules are explicitly loaded.
-
-- When a package is loaded, if it has a submodule __init__, that
- module is loaded. This is the place where required submodules can
- be loaded, the __path__ variable extended, etc. The __init__ module
- is loaded even if the package was loaded only in order to create a
- stub for a sub-package: if "import P.Q.R" is the first reference to
- P, and P has a submodule __init__, P.__init__ is loaded before P.Q
- is even searched.
-
-Caveats:
-
-- It is possible to import a package that has no __init__ submodule;
- this is not particularly useful but there may be useful applications
- for it (e.g. to manipulate its search paths from the outside!).
-
-- There are no special provisions for os.chdir(). If you plan to use
- os.chdir() before you have imported all your modules, it is better
- not to have relative pathnames in sys.path. (This could actually be
- fixed by changing the implementation of path_join() in the hook to
- absolutize paths.)
-
-- Packages and modules are introduced in sys.modules as soon as their
- loading is started. When the loading is terminated by an exception,
- the sys.modules entries remain around.
-
-- There are no special measures to support mutually recursive modules,
- but it will work under the same conditions where it works in the
- flat module space system.
-
-- Sometimes dummy entries (whose value is None) are entered in
- sys.modules, to indicate that a particular module does not exist --
- this is done to speed up the expanding search algorithm when a
- module residing at a higher level is repeatedly imported (Python
- promises that importing a previously imported module is cheap!)
-
-- Although dynamically loaded extensions are allowed inside packages,
- the current implementation (hardcoded in the interpreter) of their
- initialization may cause problems if an extension invokes the
- interpreter during its initialization.
-
-- reload() may find another version of the module only if it occurs on
- the package search path. Thus, it keeps the connection to the
- package to which the module belongs, but may find a different file.
-
-XXX Need to have an explicit name for '', e.g. '__root__'.
-
-"""
-
-
-import imp
-import string
-import sys
-import __builtin__
-
-import ihooks
-from ihooks import ModuleLoader, ModuleImporter
-
-
-class PackageLoader(ModuleLoader):
-
- """A subclass of ModuleLoader with package support.
-
- find_module_in_dir() will succeed if there's a subdirectory with
- the given name; load_module() will create a stub for a package and
- load its __init__ module if it exists.
-
- """
-
- def find_module_in_dir(self, name, dir):
- if dir is not None:
- dirname = self.hooks.path_join(dir, name)
- if self.hooks.path_isdir(dirname):
- return None, dirname, ('', '', 'PACKAGE')
- return ModuleLoader.find_module_in_dir(self, name, dir)
-
- def load_module(self, name, stuff):
- file, filename, info = stuff
- suff, mode, type = info
- if type == 'PACKAGE':
- return self.load_package(name, stuff)
- if sys.modules.has_key(name):
- m = sys.modules[name]
- else:
- sys.modules[name] = m = imp.new_module(name)
- self.set_parent(m)
- if type == imp.C_EXTENSION and '.' in name:
- return self.load_dynamic(name, stuff)
- else:
- return ModuleLoader.load_module(self, name, stuff)
-
- def load_dynamic(self, name, stuff):
- file, filename, (suff, mode, type) = stuff
- # Hack around restriction in imp.load_dynamic()
- i = string.rfind(name, '.')
- tail = name[i+1:]
- if sys.modules.has_key(tail):
- save = sys.modules[tail]
- else:
- save = None
- sys.modules[tail] = imp.new_module(name)
- try:
- m = imp.load_dynamic(tail, filename, file)
- finally:
- if save:
- sys.modules[tail] = save
- else:
- del sys.modules[tail]
- sys.modules[name] = m
- return m
-
- def load_package(self, name, stuff):
- file, filename, info = stuff
- if sys.modules.has_key(name):
- package = sys.modules[name]
- else:
- sys.modules[name] = package = imp.new_module(name)
- package.__path__ = [filename]
- self.init_package(package)
- return package
-
- def init_package(self, package):
- self.set_parent(package)
- self.set_domain(package)
- self.call_init_module(package)
-
- def set_parent(self, m):
- name = m.__name__
- if '.' in name:
- name = name[:string.rfind(name, '.')]
- else:
- name = ''
- m.__ = sys.modules[name]
-
- def set_domain(self, package):
- name = package.__name__
- package.__domain__ = domain = [name]
- while '.' in name:
- name = name[:string.rfind(name, '.')]
- domain.append(name)
- if name:
- domain.append('')
-
- def call_init_module(self, package):
- stuff = self.find_module('__init__', package.__path__)
- if stuff:
- m = self.load_module(package.__name__ + '.__init__', stuff)
- package.__init__ = m
-
-
-class PackageImporter(ModuleImporter):
-
- """Importer that understands packages and '__'."""
-
- def __init__(self, loader = None, verbose = 0):
- ModuleImporter.__init__(self,
- loader or PackageLoader(None, verbose), verbose)
-
- def import_module(self, name, globals={}, locals={}, fromlist=[]):
- if globals.has_key('__'):
- package = globals['__']
- else:
- # No calling context, assume in root package
- package = sys.modules['']
- if name[:3] in ('__.', '__'):
- p = package
- name = name[3:]
- while name[:3] in ('__.', '__'):
- p = p.__
- name = name[3:]
- if not name:
- return self.finish(package, p, '', fromlist)
- if '.' in name:
- i = string.find(name, '.')
- name, tail = name[:i], name[i:]
- else:
- tail = ''
- mname = p.__name__ and p.__name__+'.'+name or name
- m = self.get1(mname)
- return self.finish(package, m, tail, fromlist)
- if '.' in name:
- i = string.find(name, '.')
- name, tail = name[:i], name[i:]
- else:
- tail = ''
- for pname in package.__domain__:
- mname = pname and pname+'.'+name or name
- m = self.get0(mname)
- if m: break
- else:
- raise ImportError, "No such module %s" % name
- return self.finish(m, m, tail, fromlist)
-
- def finish(self, module, m, tail, fromlist):
- # Got ....A; now get ....A.B.C.D
- yname = m.__name__
- if tail and sys.modules.has_key(yname + tail): # Fast path
- yname, tail = yname + tail, ''
- m = self.get1(yname)
- while tail:
- i = string.find(tail, '.', 1)
- if i > 0:
- head, tail = tail[:i], tail[i:]
- else:
- head, tail = tail, ''
- yname = yname + head
- m = self.get1(yname)
-
- # Got ....A.B.C.D; now finalize things depending on fromlist
- if not fromlist:
- return module
- if '__' in fromlist:
- raise ImportError, "Can't import __ from anywhere"
- if not hasattr(m, '__path__'): return m
- if '*' in fromlist:
- raise ImportError, "Can't import * from a package"
- for f in fromlist:
- if hasattr(m, f): continue
- fname = yname + '.' + f
- self.get1(fname)
- return m
-
- def get1(self, name):
- m = self.get(name)
- if not m:
- raise ImportError, "No module named %s" % name
- return m
-
- def get0(self, name):
- m = self.get(name)
- if not m:
- sys.modules[name] = None
- return m
-
- def get(self, name):
- # Internal routine to get or load a module when its parent exists
- if sys.modules.has_key(name):
- return sys.modules[name]
- if '.' in name:
- i = string.rfind(name, '.')
- head, tail = name[:i], name[i+1:]
- else:
- head, tail = '', name
- path = sys.modules[head].__path__
- stuff = self.loader.find_module(tail, path)
- if not stuff:
- return None
- sys.modules[name] = m = self.loader.load_module(name, stuff)
- if head:
- setattr(sys.modules[head], tail, m)
- return m
-
- def reload(self, module):
- name = module.__name__
- if '.' in name:
- i = string.rfind(name, '.')
- head, tail = name[:i], name[i+1:]
- path = sys.modules[head].__path__
- else:
- tail = name
- path = sys.modules[''].__path__
- stuff = self.loader.find_module(tail, path)
- if not stuff:
- raise ImportError, "No module named %s" % name
- return self.loader.load_module(name, stuff)
-
- def unload(self, module):
- if hasattr(module, '__path__'):
- raise ImportError, "don't know how to unload packages yet"
- PackageImporter.unload(self, module)
-
- def install(self):
- if not sys.modules.has_key(''):
- sys.modules[''] = package = imp.new_module('')
- package.__path__ = None
- self.loader.init_package(package)
- for m in sys.modules.values():
- if not m: continue
- if not hasattr(m, '__'):
- self.loader.set_parent(m)
- ModuleImporter.install(self)
-
-
-def install(v = 0):
- ihooks.install(PackageImporter(None, v))
-
-def uninstall():
- ihooks.uninstall()
-
-def ni(v = 0):
- install(v)
-
-def no():
- uninstall()
-
-def test():
- import pdb
- try:
- testproper()
- except:
- sys.last_type, sys.last_value, sys.last_traceback = sys.exc_info()
- print
- print sys.last_type, ':', sys.last_value
- print
- pdb.pm()
-
-def testproper():
- install(1)
- try:
- import mactest
- print dir(mactest)
- raw_input('OK?')
- finally:
- uninstall()
-
-
-if __name__ == '__main__':
- test()
-else:
- install()
projects / python / commitdiff