--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/upmana/mercurial/demandimport.py	Fri Oct 30 22:21:40 2009 -0500
@@ -0,0 +1,136 @@
+# demandimport.py - global demand-loading of modules for Mercurial
+#
+# Copyright 2006, 2007 Matt Mackall <mpm@selenic.com>
+#
+# This software may be used and distributed according to the terms of the
+# GNU General Public License version 2, incorporated herein by reference.
+
+'''
+demandimport - automatic demandloading of modules
+
+To enable this module, do:
+
+  import demandimport; demandimport.enable()
+
+Imports of the following forms will be demand-loaded:
+
+  import a, b.c
+  import a.b as c
+  from a import b,c # a will be loaded immediately
+
+These imports will not be delayed:
+
+  from a import *
+  b = __import__(a)
+'''
+
+import __builtin__
+_origimport = __import__
+
+class _demandmod(object):
+    """module demand-loader and proxy"""
+    def __init__(self, name, globals, locals):
+        if '.' in name:
+            head, rest = name.split('.', 1)
+            after = [rest]
+        else:
+            head = name
+            after = []
+        object.__setattr__(self, "_data", (head, globals, locals, after))
+        object.__setattr__(self, "_module", None)
+    def _extend(self, name):
+        """add to the list of submodules to load"""
+        self._data[3].append(name)
+    def _load(self):
+        if not self._module:
+            head, globals, locals, after = self._data
+            mod = _origimport(head, globals, locals)
+            # load submodules
+            def subload(mod, p):
+                h, t = p, None
+                if '.' in p:
+                    h, t = p.split('.', 1)
+                if not hasattr(mod, h):
+                    setattr(mod, h, _demandmod(p, mod.__dict__, mod.__dict__))
+                elif t:
+                    subload(getattr(mod, h), t)
+
+            for x in after:
+                subload(mod, x)
+
+            # are we in the locals dictionary still?
+            if locals and locals.get(head) == self:
+                locals[head] = mod
+            object.__setattr__(self, "_module", mod)
+
+    def __repr__(self):
+        if self._module:
+            return "<proxied module '%s'>" % self._data[0]
+        return "<unloaded module '%s'>" % self._data[0]
+    def __call__(self, *args, **kwargs):
+        raise TypeError("%s object is not callable" % repr(self))
+    def __getattribute__(self, attr):
+        if attr in ('_data', '_extend', '_load', '_module'):
+            return object.__getattribute__(self, attr)
+        self._load()
+        return getattr(self._module, attr)
+    def __setattr__(self, attr, val):
+        self._load()
+        setattr(self._module, attr, val)
+
+def _demandimport(name, globals=None, locals=None, fromlist=None, level=None):
+    if not locals or name in ignore or fromlist == ('*',):
+        # these cases we can't really delay
+        return _origimport(name, globals, locals, fromlist)
+    elif not fromlist:
+        # import a [as b]
+        if '.' in name: # a.b
+            base, rest = name.split('.', 1)
+            # email.__init__ loading email.mime
+            if globals and globals.get('__name__', None) == base:
+                return _origimport(name, globals, locals, fromlist)
+            # if a is already demand-loaded, add b to its submodule list
+            if base in locals:
+                if isinstance(locals[base], _demandmod):
+                    locals[base]._extend(rest)
+                return locals[base]
+        return _demandmod(name, globals, locals)
+    else:
+        if level is not None:
+            # from . import b,c,d or from .a import b,c,d
+            return _origimport(name, globals, locals, fromlist, level)
+        # from a import b,c,d
+        mod = _origimport(name, globals, locals)
+        # recurse down the module chain
+        for comp in name.split('.')[1:]:
+            if not hasattr(mod, comp):
+                setattr(mod, comp, _demandmod(comp, mod.__dict__, mod.__dict__))
+            mod = getattr(mod, comp)
+        for x in fromlist:
+            # set requested submodules for demand load
+            if not(hasattr(mod, x)):
+                setattr(mod, x, _demandmod(x, mod.__dict__, locals))
+        return mod
+
+ignore = [
+    '_hashlib',
+    '_xmlplus',
+    'fcntl',
+    'win32com.gen_py',
+    'pythoncom',
+    # imported by tarfile, not available under Windows
+    'pwd',
+    'grp',
+    # imported by profile, itself imported by hotshot.stats,
+    # not available under Windows
+    'resource',
+    ]
+
+def enable():
+    "enable global demand-loading of modules"
+    __builtin__.__import__ = _demandimport
+
+def disable():
+    "disable global demand-loading of modules"
+    __builtin__.__import__ = _origimport
+