--- a/mercurial/demandimport.py Wed Jul 05 11:24:22 2017 -0400
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,331 +0,0 @@
-# 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
-
- Specify 1 as 'level' argument at construction, to import module
- relatively.
- """
- def __init__(self, name, globals, locals, level):
- if '.' in name:
- head, rest = name.split('.', 1)
- after = [rest]
- else:
- head = name
- after = []
- object.__setattr__(self, r"_data",
- (head, globals, locals, after, level, set()))
- object.__setattr__(self, r"_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)
- if mod is self:
- # In this case, _hgextimport() above should imply
- # _demandimport(). Otherwise, _hgextimport() never
- # returns _demandmod. This isn't intentional behavior,
- # in fact. (see also issue5304 for detail)
- #
- # If self._module is already bound at this point, self
- # should be already _load()-ed while _hgextimport().
- # Otherwise, there is no way to import actual module
- # as expected, because (re-)invoking _hgextimport()
- # should cause same result.
- # This is reason why _load() returns without any more
- # setup but assumes self to be already bound.
- mod = self._module
- assert mod and mod is not self, "%s, %s" % (self, mod)
- return
-
- # 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__,
- level=1))
- 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, r"_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, and if the
- parent module is a package, it must be a module. We set missing
- modules up as _demandmod instances.
- """
- symbol = getattr(mod, attr, nothing)
- nonpkg = getattr(mod, '__path__', nothing) is nothing
- if symbol is nothing:
- if nonpkg:
- # do not try relative import, which would raise ValueError,
- # and leave unknown attribute as the default __import__()
- # would do. the missing attribute will be detected later
- # while processing the import statement.
- return
- 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__, level=1))
- 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',
- 'nt', # pathlib2 tests the existence of built-in 'nt' module
- 'win32com.gen_py',
- 'win32com.shell', # 'appdirs' tries to import win32com.shell
- '_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',
- '__builtin__',
- 'builtins',
- ]
-
-if _pypy:
- ignore.extend([
- # _ctypes.pointer is shadowed by "from ... import pointer" (PyPy 5)
- '_ctypes.pointer',
- ])
-
-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()