mercurial/demandload.py

--- a/mercurial/demandload.py	Thu Dec 14 19:30:52 2006 +0100
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,135 +0,0 @@
-'''Demand load modules when used, not when imported.'''
-
-__author__ = '''Copyright 2006 Vadim Gelfer <[e-mail]>.
-This software may be used and distributed according to the terms
-of the GNU General Public License, incorporated herein by reference.'''
-
-# this is based on matt's original demandload module.  it is a
-# complete rewrite.  some time, we may need to support syntax of
-# "import foo as bar".
-
-class _importer(object):
-    '''import a module.  it is not imported until needed, and is
-    imported at most once per scope.'''
-
-    def __init__(self, scope, modname, fromlist):
-        '''scope is context (globals() or locals()) in which import
-        should be made.  modname is name of module to import.
-        fromlist is list of modules for "from foo import ..."
-        emulation.'''
-
-        self.scope = scope
-        self.modname = modname
-        self.fromlist = fromlist
-        self.mod = None
-
-    def module(self):
-        '''import the module if needed, and return.'''
-        if self.mod is None:
-            self.mod = __import__(self.modname, self.scope, self.scope,
-                                  self.fromlist)
-            del self.modname, self.fromlist
-        return self.mod
-
-class _replacer(object):
-    '''placeholder for a demand loaded module. demandload puts this in
-    a target scope.  when an attribute of this object is looked up,
-    this object is replaced in the target scope with the actual
-    module.
-
-    we use __getattribute__ to avoid namespace clashes between
-    placeholder object and real module.'''
-
-    def __init__(self, importer, target):
-        self.importer = importer
-        self.target = target
-        # consider case where we do this:
-        #   demandload(globals(), 'foo.bar foo.quux')
-        # foo will already exist in target scope when we get to
-        # foo.quux.  so we remember that we will need to demandload
-        # quux into foo's scope when we really load it.
-        self.later = []
-
-    def module(self):
-        return object.__getattribute__(self, 'importer').module()
-
-    def __getattribute__(self, key):
-        '''look up an attribute in a module and return it. replace the
-        name of the module in the caller\'s dict with the actual
-        module.'''
-
-        module = object.__getattribute__(self, 'module')()
-        target = object.__getattribute__(self, 'target')
-        importer = object.__getattribute__(self, 'importer')
-        later = object.__getattribute__(self, 'later')
-
-        if later:
-            demandload(module.__dict__, ' '.join(later))
-
-        importer.scope[target] = module
-
-        return getattr(module, key)
-
-class _replacer_from(_replacer):
-    '''placeholder for a demand loaded module.  used for "from foo
-    import ..." emulation. semantics of this are different than
-    regular import, so different implementation needed.'''
-
-    def module(self):
-        importer = object.__getattribute__(self, 'importer')
-        target = object.__getattribute__(self, 'target')
-
-        return getattr(importer.module(), target)
-
-    def __call__(self, *args, **kwargs):
-        target = object.__getattribute__(self, 'module')()
-        return target(*args, **kwargs)
-
-def demandload(scope, modules):
-    '''import modules into scope when each is first used.
-
-    scope should be the value of globals() in the module calling this
-    function, or locals() in the calling function.
-
-    modules is a string listing module names, separated by white
-    space.  names are handled like this:
-
-    foo            import foo
-    foo bar        import foo, bar
-    foo@bar        import foo as bar
-    foo.bar        import foo.bar
-    foo:bar        from foo import bar
-    foo:bar,quux   from foo import bar, quux
-    foo.bar:quux   from foo.bar import quux'''
-
-    for mod in modules.split():
-        col = mod.find(':')
-        if col >= 0:
-            fromlist = mod[col+1:].split(',')
-            mod = mod[:col]
-        else:
-            fromlist = []
-        as_ = None
-        if '@' in mod:
-            mod, as_ = mod.split("@")
-        importer = _importer(scope, mod, fromlist)
-        if fromlist:
-            for name in fromlist:
-                scope[name] = _replacer_from(importer, name)
-        else:
-            dot = mod.find('.')
-            if dot >= 0:
-                basemod = mod[:dot]
-                val = scope.get(basemod)
-                # if base module has already been demandload()ed,
-                # remember to load this submodule into its namespace
-                # when needed.
-                if isinstance(val, _replacer):
-                    later = object.__getattribute__(val, 'later')
-                    later.append(mod[dot+1:])
-                    continue
-            else:
-                basemod = mod
-            if not as_:
-                as_ = basemod
-            scope[as_] = _replacer(importer, as_)