Mercurial > hg
view mercurial/demandimport.py @ 15292:7fa471248185 stable
discovery: Fix error print mentioning a 'None' branch
When talking to old server discovery use heads of the 'None' branch to refer to
topological heads. This use of None should never make it to the end user.
author | Pierre-Yves David <pierre-yves.david@logilab.fr> |
---|---|
date | Mon, 17 Oct 2011 11:37:59 +0200 |
parents | 868282fa29d8 |
children | e3a5922e18c3 |
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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 version 2 or any later version. ''' 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__ nothing = object() try: _origimport(__builtin__.__name__, {}, {}, None, -1) except TypeError: # no level argument def _import(name, globals, locals, fromlist, level): "call _origimport with no level argument" return _origimport(name, globals, locals, fromlist) else: _import = _origimport 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 getattr(mod, h, nothing) is nothing: 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=-1): if not locals or name in ignore or fromlist == ('*',): # these cases we can't really delay return _import(name, globals, locals, fromlist, level) 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 _import(name, globals, locals, fromlist, level) # 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 != -1: # 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 getattr(mod, comp, nothing) is nothing: setattr(mod, comp, _demandmod(comp, mod.__dict__, mod.__dict__)) mod = getattr(mod, comp) for x in fromlist: # set requested submodules for demand load if getattr(mod, x, nothing) is nothing: setattr(mod, x, _demandmod(x, mod.__dict__, locals)) return mod ignore = [ '_hashlib', '_xmlplus', 'fcntl', 'win32com.gen_py', '_winreg', # 2.7 mimetypes needs immediate ImportError 'pythoncom', # imported by tarfile, not available under Windows 'pwd', 'grp', # imported by profile, itself imported by hotshot.stats, # not available under Windows 'resource', # this trips up many extension authors 'gtk', # setuptools' pkg_resources.py expects "from __main__ import x" to # raise ImportError if x not defined '__main__', '_ssl', # conditional imports in the stdlib, issue1964 'rfc822', 'mimetools', ] def enable(): "enable global demand-loading of modules" __builtin__.__import__ = _demandimport def disable(): "disable global demand-loading of modules" __builtin__.__import__ = _origimport