Mercurial > hg
view mercurial/demandimport.py @ 7175:5d8626b2c1db
parsers.c: do not try to untrack after a failure
author | Benoit Boissinot <benoit.boissinot@ens-lyon.org> |
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date | Sun, 19 Oct 2008 20:17:06 +0200 |
parents | e160f2312815 |
children | 25fc4c620e54 |
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# 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, 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) ''' _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', # 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" __builtins__["__import__"] = _demandimport def disable(): "disable global demand-loading of modules" __builtins__["__import__"] = _origimport