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Diffstat (limited to 'Lib/ni1.py')
| -rw-r--r-- | Lib/ni1.py | 434 |
1 files changed, 0 insertions, 434 deletions
diff --git a/Lib/ni1.py b/Lib/ni1.py deleted file mode 100644 index 95c9b59..0000000 --- a/Lib/ni1.py +++ /dev/null @@ -1,434 +0,0 @@ -"""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() |