Created
June 16, 2011 22:29
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__lazy__ importing
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import sys | |
from types import ModuleType | |
__path__ = [] | |
LAZY_PREFIX = "__lazy__" | |
class OnDemandModule(ModuleType): | |
def __init__(self, name): | |
ModuleType.__init__(self, name) | |
object.__setattr__(self, "__module", None) | |
def _get_module(self): | |
if object.__getattribute__(self, "__module"): | |
return object.__getattribute__(self, "__module") | |
mod = __import__(self.__name__, None, None, "*") | |
object.__setattr__(self, "__module", mod) | |
object.__setattr__(self, "__doc__", mod.__doc__) | |
object.__setattr__(self, "__file__", mod.__file__) | |
if hasattr(mod, "__path__"): | |
object.__setattr__(self, "__path__", mod.__path__) | |
return mod | |
def __dir__(self): | |
return dir(self._get_module()) | |
def __repr__(self): | |
if object.__getattribute__(self, "__module"): | |
return repr(self._get_module()) | |
else: | |
return "<%s '%s'>" % (self.__class__.__name__, self.__name__) | |
def __getattr__(self, name): | |
return getattr(self._get_module(), name) | |
def __delattr__(self, name): | |
return delattr(self._get_module(), name) | |
def __setattr__(self, name, value): | |
return setattr(self._get_module(), name, value) | |
class LazyImporter(object): | |
def find_module(self, fullname, path = None): | |
if fullname.startswith(LAZY_PREFIX + "."): | |
return self | |
else: | |
return None | |
def load_module(self, fullname): | |
realname = fullname[len(LAZY_PREFIX) + 1:] | |
if realname in sys.modules: | |
return sys.modules[realname] | |
if fullname in sys.modules: | |
return sys.modules[fullname] | |
mod = sys.modules[fullname] = OnDemandModule(realname) | |
return mod | |
_the_lazy_importer = LazyImporter() | |
sys.meta_path.append(_the_lazy_importer) | |
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