|
|
# 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()
|
|
|
|
