This commit is contained in:
Charles-François Natali 2012-02-16 19:54:48 +01:00
commit 8e3926a810
1 changed files with 130 additions and 71 deletions

View File

@ -861,6 +861,84 @@ class _ImportLockContext:
imp.release_lock()
def _resolve_name(name, package, level):
"""Resolve a relative module name to an absolute one."""
dot = len(package)
for x in range(level, 1, -1):
try:
dot = package.rindex('.', 0, dot)
except ValueError:
raise ValueError("attempted relative import beyond "
"top-level package")
if name:
return "{0}.{1}".format(package[:dot], name)
else:
return package[:dot]
def _find_module(name, path):
"""Find a module's loader."""
meta_path = sys.meta_path + _IMPLICIT_META_PATH
for finder in meta_path:
loader = finder.find_module(name, path)
if loader is not None:
# The parent import may have already imported this module.
if name not in sys.modules:
return loader
else:
return sys.modules[name].__loader__
else:
return None
def _set___package__(module):
"""Set __package__ on a module."""
# Watch out for what comes out of sys.modules to not be a module,
# e.g. an int.
try:
module.__package__ = module.__name__
if not hasattr(module, '__path__'):
module.__package__ = module.__package__.rpartition('.')[0]
except AttributeError:
pass
def _sanity_check(name, package, level):
"""Verify arguments are "sane"."""
if package:
if not hasattr(package, 'rindex'):
raise ValueError("__package__ not set to a string")
elif package not in sys.modules:
msg = ("Parent module {0!r} not loaded, cannot perform relative "
"import")
raise SystemError(msg.format(package))
if not name and level == 0:
raise ValueError("Empty module name")
def _find_search_path(name, import_):
"""Find the search path for a module.
import_ is expected to be a callable which takes the name of a module to
import. It is required to decouple the function from importlib.
"""
path = None
parent = name.rpartition('.')[0]
if parent:
if parent not in sys.modules:
import_(parent)
# Backwards-compatibility; be nicer to skip the dict lookup.
parent_module = sys.modules[parent]
try:
path = parent_module.__path__
except AttributeError:
msg = (_ERR_MSG + '; {} is not a package').format(name, parent)
raise ImportError(msg)
return parent, path
_IMPLICIT_META_PATH = [BuiltinImporter, FrozenImporter, _DefaultPathFinder]
_ERR_MSG = 'No module named {!r}'
@ -874,27 +952,9 @@ def _gcd_import(name, package=None, level=0):
the loader did not.
"""
if package:
if not hasattr(package, 'rindex'):
raise ValueError("__package__ not set to a string")
elif package not in sys.modules:
msg = ("Parent module {0!r} not loaded, cannot perform relative "
"import")
raise SystemError(msg.format(package))
if not name and level == 0:
raise ValueError("Empty module name")
_sanity_check(name, package, level)
if level > 0:
dot = len(package)
for x in range(level, 1, -1):
try:
dot = package.rindex('.', 0, dot)
except ValueError:
raise ValueError("attempted relative import beyond "
"top-level package")
if name:
name = "{0}.{1}".format(package[:dot], name)
else:
name = package[:dot]
name = _resolve_name(name, package, level)
with _ImportLockContext():
try:
module = sys.modules[name]
@ -905,70 +965,33 @@ def _gcd_import(name, package=None, level=0):
return module
except KeyError:
pass
parent = name.rpartition('.')[0]
path = None
if parent:
if parent not in sys.modules:
_gcd_import(parent)
# Backwards-compatibility; be nicer to skip the dict lookup.
parent_module = sys.modules[parent]
try:
path = parent_module.__path__
except AttributeError:
msg = (_ERR_MSG + '; {} is not a package').format(name, parent)
raise ImportError(msg)
meta_path = sys.meta_path + _IMPLICIT_META_PATH
for finder in meta_path:
loader = finder.find_module(name, path)
if loader is not None:
# The parent import may have already imported this module.
if name not in sys.modules:
loader.load_module(name)
break
else:
parent, path = _find_search_path(name, _gcd_import)
loader = _find_module(name, path)
if loader is None:
raise ImportError(_ERR_MSG.format(name))
elif name not in sys.modules:
# The parent import may have already imported this module.
loader.load_module(name)
# Backwards-compatibility; be nicer to skip the dict lookup.
module = sys.modules[name]
if parent:
# Set the module as an attribute on its parent.
parent_module = sys.modules[parent]
setattr(parent_module, name.rpartition('.')[2], module)
# Set __package__ if the loader did not.
if not hasattr(module, '__package__') or module.__package__ is None:
# Watch out for what comes out of sys.modules to not be a module,
# e.g. an int.
try:
module.__package__ = module.__name__
if not hasattr(module, '__path__'):
module.__package__ = module.__package__.rpartition('.')[0]
except AttributeError:
pass
_set___package__(module)
return module
def __import__(name, globals={}, locals={}, fromlist=[], level=0):
"""Import a module.
def _return_module(module, name, fromlist, level, import_):
"""Figure out what __import__ should return.
The 'globals' argument is used to infer where the import is occuring from
to handle relative imports. The 'locals' argument is ignored. The
'fromlist' argument specifies what should exist as attributes on the module
being imported (e.g. ``from module import <fromlist>``). The 'level'
argument represents the package location to import from in a relative
import (e.g. ``from ..pkg import mod`` would have a 'level' of 2).
The import_ parameter is a callable which takes the name of module to
import. It is required to decouple the function from assuming importlib's
import implementation is desired.
"""
if not hasattr(name, 'rpartition'):
raise TypeError("module name must be str, not {}".format(type(name)))
if level == 0:
module = _gcd_import(name)
else:
# __package__ is not guaranteed to be defined or could be set to None
# to represent that its proper value is unknown
package = globals.get('__package__')
if package is None:
package = globals['__name__']
if '__path__' not in globals:
package = package.rpartition('.')[0]
module = _gcd_import(name, package, level)
# The hell that is fromlist ...
if not fromlist:
# Return up to the first dot in 'name'. This is complicated by the fact
@ -989,12 +1012,48 @@ def __import__(name, globals={}, locals={}, fromlist=[], level=0):
fromlist.extend(module.__all__)
for x in (y for y in fromlist if not hasattr(module,y)):
try:
_gcd_import('{0}.{1}'.format(module.__name__, x))
import_('{0}.{1}'.format(module.__name__, x))
except ImportError:
pass
return module
def _calc___package__(globals):
"""Calculate what __package__ should be.
__package__ is not guaranteed to be defined or could be set to None
to represent that its proper value is unknown.
"""
package = globals.get('__package__')
if package is None:
package = globals['__name__']
if '__path__' not in globals:
package = package.rpartition('.')[0]
return package
def __import__(name, globals={}, locals={}, fromlist=[], level=0):
"""Import a module.
The 'globals' argument is used to infer where the import is occuring from
to handle relative imports. The 'locals' argument is ignored. The
'fromlist' argument specifies what should exist as attributes on the module
being imported (e.g. ``from module import <fromlist>``). The 'level'
argument represents the package location to import from in a relative
import (e.g. ``from ..pkg import mod`` would have a 'level' of 2).
"""
if not hasattr(name, 'rpartition'):
raise TypeError("module name must be str, not {}".format(type(name)))
if level == 0:
module = _gcd_import(name)
else:
package = _calc___package__(globals)
module = _gcd_import(name, package, level)
return _return_module(module, name, fromlist, level, _gcd_import)
def _setup(sys_module, imp_module):
"""Setup importlib by importing needed built-in modules and injecting them
into the global namespace.