Mercurial > hg
view mercurial/demandimport.py @ 29497:ee2027195847
perf: define command annotation locally for Mercurial earlier than 3.1
Before this patch, using cmdutil.command() for "@command" annotation
prevents perf.py from being loaded by Mercurial earlier than 1.9 (or
2daa5179e73f), because cmdutil.command() isn't available in such
Mercurial, even though there are some code paths for Mercurial earlier
than 1.9.
For example, setting "_prereadsize" attribute in perfindex() and
perfnodelookup() is effective only with hg earlier than 1.8 (or
61c9bc3da402).
In addition to it, "norepo" option of command annotation has been
available since 3.1 (or 75a96326cecb), and this is another blocker for
loading perf.py with earlier Mercurial.
============ ============ ======
command of
hg version cmdutil norepo
============ ============ ======
3.1 or later o o
1.9 or later o x
earlier x x
============ ============ ======
This patch defines "command()" for annotation locally as below:
- define wrapper of existing cmdutil.command(), if cmdutil.command()
doesn't support "norepo"
(for Mercurial earlier than 3.1)
- define full command() locally with minimum function, if
cmdutil.command() isn't available at runtime
(for Mercurial earlier than 1.9)
This patch also defines parsealiases() locally without examining
whether it is available or not, because it is small enough to define
locally.
author | FUJIWARA Katsunori <foozy@lares.dti.ne.jp> |
---|---|
date | Tue, 05 Jul 2016 07:25:51 +0900 |
parents | fcaf20175b1b |
children | 8960fcb76ca4 |
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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) ''' from __future__ import absolute_import import contextlib import os import sys # __builtin__ in Python 2, builtins in Python 3. try: import __builtin__ as builtins except ImportError: import builtins contextmanager = contextlib.contextmanager _origimport = __import__ nothing = object() # Python 3 doesn't have relative imports nor level -1. level = -1 if sys.version_info[0] >= 3: level = 0 _import = _origimport def _hgextimport(importfunc, name, globals, *args, **kwargs): try: return importfunc(name, globals, *args, **kwargs) except ImportError: if not globals: raise # extensions are loaded with "hgext_" prefix hgextname = 'hgext_%s' % name nameroot = hgextname.split('.', 1)[0] contextroot = globals.get('__name__', '').split('.', 1)[0] if nameroot != contextroot: raise # retry to import with "hgext_" prefix return importfunc(hgextname, globals, *args, **kwargs) class _demandmod(object): """module demand-loader and proxy""" def __init__(self, name, globals, locals, level=level): if '.' in name: head, rest = name.split('.', 1) after = [rest] else: head = name after = [] object.__setattr__(self, "_data", (head, globals, locals, after, level, set())) object.__setattr__(self, "_module", None) def _extend(self, name): """add to the list of submodules to load""" self._data[3].append(name) def _addref(self, name): """Record that the named module ``name`` imports this module. References to this proxy class having the name of this module will be replaced at module load time. We assume the symbol inside the importing module is identical to the "head" name of this module. We don't actually know if "as X" syntax is being used to change the symbol name because this information isn't exposed to __import__. """ self._data[5].add(name) def _load(self): if not self._module: head, globals, locals, after, level, modrefs = self._data mod = _hgextimport(_import, head, globals, locals, None, level) # 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) # Replace references to this proxy instance with the actual module. if locals and locals.get(head) == self: locals[head] = mod for modname in modrefs: modref = sys.modules.get(modname, None) if modref and getattr(modref, head, None) == self: setattr(modref, 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', '_addref'): return object.__getattribute__(self, attr) self._load() return getattr(self._module, attr) def __setattr__(self, attr, val): self._load() setattr(self._module, attr, val) _pypy = '__pypy__' in sys.builtin_module_names def _demandimport(name, globals=None, locals=None, fromlist=None, level=level): if not locals or name in ignore or fromlist == ('*',): # these cases we can't really delay return _hgextimport(_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, level) else: # There is a fromlist. # from a import b,c,d # from . import b,c,d # from .a import b,c,d # level == -1: relative and absolute attempted (Python 2 only). # level >= 0: absolute only (Python 2 w/ absolute_import and Python 3). # The modern Mercurial convention is to use absolute_import everywhere, # so modern Mercurial code will have level >= 0. # The name of the module the import statement is located in. globalname = globals.get('__name__') def processfromitem(mod, attr): """Process an imported symbol in the import statement. If the symbol doesn't exist in the parent module, it must be a module. We set missing modules up as _demandmod instances. """ symbol = getattr(mod, attr, nothing) if symbol is nothing: mn = '%s.%s' % (mod.__name__, attr) if mn in ignore: importfunc = _origimport else: importfunc = _demandmod symbol = importfunc(attr, mod.__dict__, locals, level=1) setattr(mod, attr, symbol) # Record the importing module references this symbol so we can # replace the symbol with the actual module instance at load # time. if globalname and isinstance(symbol, _demandmod): symbol._addref(globalname) def chainmodules(rootmod, modname): # recurse down the module chain, and return the leaf module mod = rootmod for comp in modname.split('.')[1:]: if getattr(mod, comp, nothing) is nothing: setattr(mod, comp, _demandmod(comp, mod.__dict__, mod.__dict__)) mod = getattr(mod, comp) return mod if level >= 0: if name: # "from a import b" or "from .a import b" style rootmod = _hgextimport(_origimport, name, globals, locals, level=level) mod = chainmodules(rootmod, name) elif _pypy: # PyPy's __import__ throws an exception if invoked # with an empty name and no fromlist. Recreate the # desired behaviour by hand. mn = globalname mod = sys.modules[mn] if getattr(mod, '__path__', nothing) is nothing: mn = mn.rsplit('.', 1)[0] mod = sys.modules[mn] if level > 1: mn = mn.rsplit('.', level - 1)[0] mod = sys.modules[mn] else: mod = _hgextimport(_origimport, name, globals, locals, level=level) for x in fromlist: processfromitem(mod, x) return mod # But, we still need to support lazy loading of standard library and 3rd # party modules. So handle level == -1. mod = _hgextimport(_origimport, name, globals, locals) mod = chainmodules(mod, name) for x in fromlist: processfromitem(mod, x) return mod ignore = [ '__future__', '_hashlib', # ImportError during pkg_resources/__init__.py:fixup_namespace_package '_imp', '_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 '_sre', # issue4920 'rfc822', 'mimetools', 'sqlalchemy.events', # has import-time side effects (issue5085) # setuptools 8 expects this module to explode early when not on windows 'distutils.msvc9compiler' ] def isenabled(): return builtins.__import__ == _demandimport def enable(): "enable global demand-loading of modules" if os.environ.get('HGDEMANDIMPORT') != 'disable': builtins.__import__ = _demandimport def disable(): "disable global demand-loading of modules" builtins.__import__ = _origimport @contextmanager def deactivated(): "context manager for disabling demandimport in 'with' blocks" demandenabled = isenabled() if demandenabled: disable() try: yield finally: if demandenabled: enable()