Mercurial > hg-stable
changeset 32458:0906b85bf222
demandimport: move to separate package
In Python 3, demand loading is per-package. Keeping demandimport in the
mercurial package would disable demand loading for any modules in
mercurial.
| author | Siddharth Agarwal <sid0@fb.com> |
|---|---|
| date | Sun, 21 May 2017 12:10:53 -0700 |
| parents | d02888308235 |
| children | 778dc37ce683 |
| files | contrib/import-checker.py hgdemandimport/__init__.py hgdemandimport/demandimportpy2.py mercurial/__init__.py mercurial/demandimport.py setup.py |
| diffstat | 6 files changed, 365 insertions(+), 335 deletions(-) [+] |
line wrap: on
line diff
--- a/contrib/import-checker.py Sun May 21 12:09:01 2017 -0700 +++ b/contrib/import-checker.py Sun May 21 12:10:53 2017 -0700 @@ -25,7 +25,9 @@ ) # Whitelist of symbols that can be directly imported. -directsymbols = () +directsymbols = ( + 'demandimport', +) # Modules that must be aliased because they are commonly confused with # common variables and can create aliasing and readability issues.
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/hgdemandimport/__init__.py Sun May 21 12:10:53 2017 -0700 @@ -0,0 +1,23 @@ +# hgdemandimport - global demand-loading of modules for Mercurial +# +# Copyright 2017 Facebook Inc. +# +# 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 demand-loading of modules''' + +# This is in a separate package from mercurial because in Python 3, +# demand loading is per-package. Keeping demandimport in the mercurial package +# would disable demand loading for any modules in mercurial. + +from __future__ import absolute_import + +from . import demandimportpy2 as demandimport + +# Re-export. +ignore = demandimport.ignore +isenabled = demandimport.isenabled +enable = demandimport.enable +disable = demandimport.disable +deactivated = demandimport.deactivated
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/hgdemandimport/demandimportpy2.py Sun May 21 12:10:53 2017 -0700 @@ -0,0 +1,332 @@ +# 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 locals is None 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', + 'urwid.command_map', # for pudb + ] + +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()
--- a/mercurial/__init__.py Sun May 21 12:09:01 2017 -0700 +++ b/mercurial/__init__.py Sun May 21 12:10:53 2017 -0700 @@ -9,6 +9,10 @@ import sys +# Allow 'from mercurial import demandimport' to keep working. +import hgdemandimport +demandimport = hgdemandimport + __all__ = [] # Python 3 uses a custom module loader that transforms source code between
--- a/mercurial/demandimport.py Sun May 21 12:09:01 2017 -0700 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,332 +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 locals is None 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', - 'urwid.command_map', # for pudb - ] - -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()
--- a/setup.py Sun May 21 12:09:01 2017 -0700 +++ b/setup.py Sun May 21 12:10:53 2017 -0700 @@ -587,7 +587,8 @@ 'mercurial.pure', 'hgext', 'hgext.convert', 'hgext.fsmonitor', 'hgext.fsmonitor.pywatchman', 'hgext.highlight', - 'hgext.largefiles', 'hgext.zeroconf', 'hgext3rd'] + 'hgext.largefiles', 'hgext.zeroconf', 'hgext3rd', + 'hgdemandimport'] common_depends = ['mercurial/bitmanipulation.h', 'mercurial/compat.h', @@ -793,7 +794,7 @@ package_data=packagedata, cmdclass=cmdclass, distclass=hgdist, - options={'py2exe': {'packages': ['hgext', 'email']}, + options={'py2exe': {'packages': ['hgdemandimport', 'hgext', 'email']}, 'bdist_mpkg': {'zipdist': False, 'license': 'COPYING', 'readme': 'contrib/macosx/Readme.html',