mirror of
https://github.com/python/cpython.git
synced 2025-10-31 21:51:50 +00:00
redesign/rebuild around the ImportManager concept.
This commit is contained in:
Greg Stein
parent
bb05b2520d
commit
f23aa1ee9f
1 changed files with 311 additions and 169 deletions
470
Lib/imputil.py
470
Lib/imputil.py
|
|
@ -27,75 +27,204 @@
|
|||
import struct
|
||||
import marshal
|
||||
|
||||
class Importer:
|
||||
"Base class for replacing standard import functions."
|
||||
_StringType = type('')
|
||||
_ModuleType = type(sys)
|
||||
|
||||
class ImportManager:
|
||||
"Manage the import process."
|
||||
|
||||
def install(self):
|
||||
### warning: Python 1.6 will have a different hook mechanism; this
|
||||
### code will need to change.
|
||||
self.__chain_import = __builtin__.__import__
|
||||
self.__chain_reload = __builtin__.reload
|
||||
__builtin__.__import__ = self._import_hook
|
||||
__builtin__.reload = self._reload_hook
|
||||
### fix this
|
||||
#__builtin__.reload = None
|
||||
#__builtin__.reload = self._reload_hook
|
||||
|
||||
def add_suffix(self, suffix, importer):
|
||||
assert isinstance(importer, SuffixImporter)
|
||||
self.suffixes.append((suffix, importer))
|
||||
|
||||
######################################################################
|
||||
#
|
||||
# PRIVATE METHODS
|
||||
#
|
||||
def _import_hook(self, name, globals=None, locals=None, fromlist=None):
|
||||
"""Python calls this hook to locate and import a module.
|
||||
def __init__(self):
|
||||
# we're definitely going to be importing something in the future,
|
||||
# so let's just load the OS-related facilities.
|
||||
if not _os_stat:
|
||||
_os_bootstrap()
|
||||
|
||||
This method attempts to load the (dotted) module name. If it cannot
|
||||
find it, then it delegates the import to the next import hook in the
|
||||
chain (where "next" is defined as the import hook that was in place
|
||||
at the time this Importer instance was installed).
|
||||
"""
|
||||
# Initialize the set of suffixes that we recognize and import.
|
||||
# The default will import dynamic-load modules first, followed by
|
||||
# .py files (or a .py file's cached bytecode)
|
||||
self.suffixes = [ ]
|
||||
for desc in imp.get_suffixes():
|
||||
if desc[2] == imp.C_EXTENSION:
|
||||
self.suffixes.append((desc[0], DynLoadSuffixImporter(desc)))
|
||||
self.suffixes.append(('.py', PySuffixImporter()))
|
||||
|
||||
### insert a fast-path check for whether the module is already
|
||||
### loaded? use a variant of _determine_import_context() which
|
||||
### returns a context regardless of Importer used. generate an
|
||||
### fqname and look in sys.modules for it.
|
||||
# This is the importer that we use for grabbing stuff from the
|
||||
# filesystem. It defines one more method (import_from_dir) for our use.
|
||||
self.fs_imp = _FilesystemImporter(self.suffixes)
|
||||
|
||||
### note that given module a.b which imports c, if c is already
|
||||
### loaded, python still wants to look for a.c
|
||||
def _import_hook(self, fqname, globals=None, locals=None, fromlist=None):
|
||||
"""Python calls this hook to locate and import a module."""
|
||||
|
||||
parts = strop.split(fqname, '.')
|
||||
|
||||
# determine the context of this import
|
||||
parent = self._determine_import_context(globals)
|
||||
|
||||
# import the module within the context, or from the default context
|
||||
top, tail = self._import_top_module(parent, name)
|
||||
if top is None:
|
||||
# the module was not found; delegate to the next import hook
|
||||
# if there is a parent, then its importer should manage this import
|
||||
if parent:
|
||||
module = parent.__importer__._do_import(parent, parts, fromlist)
|
||||
if module:
|
||||
return module
|
||||
|
||||
# has the top module already been imported?
|
||||
try:
|
||||
top_module = sys.modules[parts[0]]
|
||||
except KeyError:
|
||||
|
||||
# look for the topmost module
|
||||
top_module = self._import_top_module(parts[0])
|
||||
if not top_module:
|
||||
# the topmost module wasn't found at all.
|
||||
raise ImportError, 'No module named ' + fqname
|
||||
return self.__chain_import(name, globals, locals, fromlist)
|
||||
|
||||
# the top module may be under the control of a different importer.
|
||||
# if so, then defer to that importer for completion of the import.
|
||||
# note it may be self, or is undefined so we (self) may as well
|
||||
# finish the import.
|
||||
importer = top.__dict__.get('__importer__', self)
|
||||
return importer._finish_import(top, tail, fromlist)
|
||||
# fast-path simple imports
|
||||
if len(parts) == 1:
|
||||
if not fromlist:
|
||||
return top_module
|
||||
|
||||
def _finish_import(self, top, tail, fromlist):
|
||||
if not top_module.__dict__.get('__ispkg__'):
|
||||
# __ispkg__ isn't defined (the module was not imported by us), or
|
||||
# it is zero.
|
||||
#
|
||||
# In the former case, there is no way that we could import
|
||||
# sub-modules that occur in the fromlist (but we can't raise an
|
||||
# error because it may just be names) because we don't know how
|
||||
# to deal with packages that were imported by other systems.
|
||||
#
|
||||
# In the latter case (__ispkg__ == 0), there can't be any sub-
|
||||
# modules present, so we can just return.
|
||||
#
|
||||
# In both cases, since len(parts) == 1, the top_module is also
|
||||
# the "bottom" which is the defined return when a fromlist exists.
|
||||
return top_module
|
||||
|
||||
importer = top_module.__dict__.get('__importer__')
|
||||
if importer:
|
||||
return importer._finish_import(top_module, parts[1:], fromlist)
|
||||
|
||||
# If the importer does not exist, then we have to bail. A missing importer
|
||||
# means that something else imported the module, and we have no knowledge
|
||||
# of how to get sub-modules out of the thing.
|
||||
raise ImportError, 'No module named ' + fqname
|
||||
return self.__chain_import(name, globals, locals, fromlist)
|
||||
|
||||
def _determine_import_context(self, globals):
|
||||
"""Returns the context in which a module should be imported.
|
||||
|
||||
The context could be a loaded (package) module and the imported module
|
||||
will be looked for within that package. The context could also be None,
|
||||
meaning there is no context -- the module should be looked for as a
|
||||
"top-level" module.
|
||||
"""
|
||||
|
||||
if not globals or not globals.get('__importer__'):
|
||||
# globals does not refer to one of our modules or packages. That
|
||||
# implies there is no relative import context (as far as we are
|
||||
# concerned), and it should just pick it off the standard path.
|
||||
return None
|
||||
|
||||
# The globals refer to a module or package of ours. It will define
|
||||
# the context of the new import. Get the module/package fqname.
|
||||
parent_fqname = globals['__name__']
|
||||
|
||||
# if a package is performing the import, then return itself (imports
|
||||
# refer to pkg contents)
|
||||
if globals['__ispkg__']:
|
||||
parent = sys.modules[parent_fqname]
|
||||
assert globals is parent.__dict__
|
||||
return parent
|
||||
|
||||
i = strop.rfind(parent_fqname, '.')
|
||||
|
||||
# a module outside of a package has no particular import context
|
||||
if i == -1:
|
||||
return None
|
||||
|
||||
# if a module in a package is performing the import, then return the
|
||||
# package (imports refer to siblings)
|
||||
parent_fqname = parent_fqname[:i]
|
||||
parent = sys.modules[parent_fqname]
|
||||
assert parent.__name__ == parent_fqname
|
||||
return parent
|
||||
|
||||
def _import_top_module(self, name):
|
||||
# scan sys.path looking for a location in the filesystem that contains
|
||||
# the module, or an Importer object that can import the module.
|
||||
for item in sys.path:
|
||||
if type(item) == _StringType:
|
||||
module = self.fs_imp.import_from_dir(item, name)
|
||||
else:
|
||||
module = item.import_top(name)
|
||||
if module:
|
||||
return module
|
||||
return None
|
||||
|
||||
def _reload_hook(self, module):
|
||||
"Python calls this hook to reload a module."
|
||||
|
||||
# reloading of a module may or may not be possible (depending on the
|
||||
# importer), but at least we can validate that it's ours to reload
|
||||
importer = module.__dict__.get('__importer__')
|
||||
if not importer:
|
||||
return self.__chain_reload(module)
|
||||
|
||||
# okay. it is using the imputil system, and we must delegate it, but
|
||||
# we don't know what to do (yet)
|
||||
### we should blast the module dict and do another get_code(). need to
|
||||
### flesh this out and add proper docco...
|
||||
raise SystemError, "reload not yet implemented"
|
||||
|
||||
|
||||
class Importer:
|
||||
"Base class for replacing standard import functions."
|
||||
|
||||
def install(self):
|
||||
sys.path.insert(0, self)
|
||||
|
||||
def import_top(self, name):
|
||||
"Import a top-level module."
|
||||
return self._import_one(None, name, name)
|
||||
|
||||
######################################################################
|
||||
#
|
||||
# PRIVATE METHODS
|
||||
#
|
||||
def _finish_import(self, top, parts, fromlist):
|
||||
# if "a.b.c" was provided, then load the ".b.c" portion down from
|
||||
# below the top-level module.
|
||||
bottom = self._load_tail(top, tail)
|
||||
bottom = self._load_tail(top, parts)
|
||||
|
||||
# if the form is "import a.b.c", then return "a"
|
||||
if not fromlist:
|
||||
# no fromlist: return the top of the import tree
|
||||
return top
|
||||
|
||||
# the top module was imported by self, or it was not imported through
|
||||
# the Importer mechanism and self is simply handling the import of
|
||||
# the sub-modules and fromlist.
|
||||
# the top module was imported by self.
|
||||
#
|
||||
# this means that the bottom module was also imported by self, or we
|
||||
# are handling things in the absence of a prior Importer
|
||||
#
|
||||
# ### why the heck are we handling it? what is the example scenario
|
||||
# ### where this happens? note that we can't determine is_package()
|
||||
# ### for non-Importer modules.
|
||||
# this means that the bottom module was also imported by self (just
|
||||
# now, or in the past and we fetched it from sys.modules).
|
||||
#
|
||||
# since we imported/handled the bottom module, this means that we can
|
||||
# also handle its fromlist (and reliably determine is_package()).
|
||||
# also handle its fromlist (and reliably use __ispkg__).
|
||||
|
||||
# if the bottom node is a package, then (potentially) import some modules.
|
||||
#
|
||||
|
|
@ -107,99 +236,12 @@ def _finish_import(self, top, tail, fromlist):
|
|||
# from the bottom (package) module; some will be modules that
|
||||
# we imported and stored in the namespace, others are expected
|
||||
# to be present already.
|
||||
if self._is_package(bottom.__dict__):
|
||||
if bottom.__ispkg__:
|
||||
self._import_fromlist(bottom, fromlist)
|
||||
|
||||
# if the form is "from a.b import c, d" then return "b"
|
||||
return bottom
|
||||
|
||||
def _reload_hook(self, module):
|
||||
"Python calls this hook to reload a module."
|
||||
|
||||
# reloading of a module may or may not be possible (depending on the
|
||||
# importer), but at least we can validate that it's ours to reload
|
||||
importer = module.__dict__.get('__importer__', None)
|
||||
if importer is not self:
|
||||
return self.__chain_reload(module)
|
||||
|
||||
# okay. it is ours, but we don't know what to do (yet)
|
||||
### we should blast the module dict and do another get_code(). need to
|
||||
### flesh this out and add proper docco...
|
||||
raise SystemError, "reload not yet implemented"
|
||||
|
||||
def _determine_import_context(self, globals):
|
||||
"""Returns the context in which a module should be imported.
|
||||
|
||||
The context could be a loaded (package) module and the imported module
|
||||
will be looked for within that package. The context could also be None,
|
||||
meaning there is no context -- the module should be looked for as a
|
||||
"top-level" module.
|
||||
"""
|
||||
|
||||
if not globals or \
|
||||
globals.get('__importer__', None) is not self:
|
||||
# globals does not refer to one of our modules or packages.
|
||||
# That implies there is no relative import context, and it
|
||||
# should just pick it off the standard path.
|
||||
return None
|
||||
|
||||
# The globals refer to a module or package of ours. It will define
|
||||
# the context of the new import. Get the module/package fqname.
|
||||
parent_fqname = globals['__name__']
|
||||
|
||||
# for a package, return itself (imports refer to pkg contents)
|
||||
if self._is_package(globals):
|
||||
parent = sys.modules[parent_fqname]
|
||||
assert globals is parent.__dict__
|
||||
return parent
|
||||
|
||||
i = strop.rfind(parent_fqname, '.')
|
||||
|
||||
# a module outside of a package has no particular import context
|
||||
if i == -1:
|
||||
return None
|
||||
|
||||
# for a module in a package, return the package (imports refer to siblings)
|
||||
parent_fqname = parent_fqname[:i]
|
||||
parent = sys.modules[parent_fqname]
|
||||
assert parent.__name__ == parent_fqname
|
||||
return parent
|
||||
|
||||
def _import_top_module(self, parent, name):
|
||||
"""Locate the top of the import tree (relative or absolute).
|
||||
|
||||
parent defines the context in which the import should occur. See
|
||||
_determine_import_context() for details.
|
||||
|
||||
Returns a tuple (module, tail). module is the loaded (top-level) module,
|
||||
or None if the module is not found. tail is the remaining portion of
|
||||
the dotted name.
|
||||
"""
|
||||
i = strop.find(name, '.')
|
||||
if i == -1:
|
||||
head = name
|
||||
tail = ""
|
||||
else:
|
||||
head = name[:i]
|
||||
tail = name[i+1:]
|
||||
if parent:
|
||||
fqname = "%s.%s" % (parent.__name__, head)
|
||||
else:
|
||||
fqname = head
|
||||
module = self._import_one(parent, head, fqname)
|
||||
if module:
|
||||
# the module was relative, or no context existed (the module was
|
||||
# simply found on the path).
|
||||
return module, tail
|
||||
if parent:
|
||||
# we tried relative, now try an absolute import (from the path)
|
||||
module = self._import_one(None, head, head)
|
||||
if module:
|
||||
return module, tail
|
||||
|
||||
# the module wasn't found
|
||||
return None, None
|
||||
|
||||
def _import_one(self, parent, modname, fqname):
|
||||
"Import a single module."
|
||||
|
||||
|
|
@ -214,42 +256,49 @@ def _import_one(self, parent, modname, fqname):
|
|||
if result is None:
|
||||
return None
|
||||
|
||||
# did get_code() return an actual module? (rather than a code object)
|
||||
is_module = type(result[1]) is type(sys)
|
||||
### backwards-compat
|
||||
if len(result) == 2:
|
||||
result = result + ({},)
|
||||
|
||||
# use the returned module, or create a new one to exec code into
|
||||
if is_module:
|
||||
module = result[1]
|
||||
else:
|
||||
module = imp.new_module(fqname)
|
||||
|
||||
### record packages a bit differently??
|
||||
module.__importer__ = self
|
||||
module.__ispkg__ = result[0]
|
||||
|
||||
# if present, the third item is a set of values to insert into the module
|
||||
if len(result) > 2:
|
||||
module.__dict__.update(result[2])
|
||||
|
||||
# the module is almost ready... make it visible
|
||||
sys.modules[fqname] = module
|
||||
|
||||
# execute the code within the module's namespace
|
||||
if not is_module:
|
||||
exec result[1] in module.__dict__
|
||||
module = self._process_result(result, fqname)
|
||||
|
||||
# insert the module into its parent
|
||||
if parent:
|
||||
setattr(parent, modname, module)
|
||||
return module
|
||||
|
||||
def _load_tail(self, m, tail):
|
||||
def _process_result(self, (ispkg, code, values), fqname):
|
||||
# did get_code() return an actual module? (rather than a code object)
|
||||
is_module = type(code) is _ModuleType
|
||||
|
||||
# use the returned module, or create a new one to exec code into
|
||||
if is_module:
|
||||
module = code
|
||||
else:
|
||||
module = imp.new_module(fqname)
|
||||
|
||||
### record packages a bit differently??
|
||||
module.__importer__ = self
|
||||
module.__ispkg__ = ispkg
|
||||
|
||||
# insert additional values into the module (before executing the code)
|
||||
module.__dict__.update(values)
|
||||
|
||||
# the module is almost ready... make it visible
|
||||
sys.modules[fqname] = module
|
||||
|
||||
# execute the code within the module's namespace
|
||||
if not is_module:
|
||||
exec code in module.__dict__
|
||||
|
||||
return module
|
||||
|
||||
def _load_tail(self, m, parts):
|
||||
"""Import the rest of the modules, down from the top-level module.
|
||||
|
||||
Returns the last module in the dotted list of modules.
|
||||
"""
|
||||
if tail:
|
||||
for part in strop.splitfields(tail, '.'):
|
||||
for part in parts:
|
||||
fqname = "%s.%s" % (m.__name__, part)
|
||||
m = self._import_one(m, part, fqname)
|
||||
if not m:
|
||||
|
|
@ -273,17 +322,20 @@ def _import_fromlist(self, package, fromlist):
|
|||
if not submod:
|
||||
raise ImportError, "cannot import name " + subname
|
||||
|
||||
def _is_package(self, module_dict):
|
||||
"""Determine if a given module (dictionary) specifies a package.
|
||||
def _do_import(self, parent, parts, fromlist):
|
||||
"""Attempt to import the module relative to parent.
|
||||
|
||||
The package status is in the module-level name __ispkg__. The module
|
||||
must also have been imported by self, so that we can reliably apply
|
||||
semantic meaning to __ispkg__.
|
||||
|
||||
### weaken the test to issubclass(Importer)?
|
||||
This method is used when the import context specifies that <self>
|
||||
imported the parent module.
|
||||
"""
|
||||
return module_dict.get('__importer__', None) is self and \
|
||||
module_dict['__ispkg__']
|
||||
top_name = parts[0]
|
||||
top_fqname = parent.__name__ + '.' + top_name
|
||||
top_module = self._import_one(parent, top_name, top_fqname)
|
||||
if not top_module:
|
||||
# this importer and parent could not find the module (relatively)
|
||||
return None
|
||||
|
||||
return self._finish_import(top_module, parts[1:], fromlist)
|
||||
|
||||
######################################################################
|
||||
#
|
||||
|
|
@ -301,7 +353,7 @@ def get_code(self, parent, modname, fqname):
|
|||
dotted name from the "root" of the module namespace down to the modname.
|
||||
If there is no parent, then modname==fqname.
|
||||
|
||||
This method should return None, a 2-tuple, or a 3-tuple.
|
||||
This method should return None, or a 3-tuple.
|
||||
|
||||
* If the module was not found, then None should be returned.
|
||||
|
||||
|
|
@ -312,9 +364,9 @@ def get_code(self, parent, modname, fqname):
|
|||
executed within the new module's namespace). This item can also
|
||||
be a fully-loaded module object (e.g. loaded from a shared lib).
|
||||
|
||||
* If present, the third item is a dictionary of name/value pairs that
|
||||
will be inserted into new module before the code object is executed.
|
||||
This provided in case the module's code expects certain values (such
|
||||
* The third item is a dictionary of name/value pairs that will be
|
||||
inserted into new module before the code object is executed. This
|
||||
is provided in case the module's code expects certain values (such
|
||||
as where the module was found). When the second item is a module
|
||||
object, then these names/values will be inserted *after* the module
|
||||
has been loaded/initialized.
|
||||
|
|
@ -652,6 +704,92 @@ def get_code(self, parent, modname, fqname):
|
|||
return 0, module, { }
|
||||
|
||||
|
||||
######################################################################
|
||||
#
|
||||
# Internal importer used for importing from the filesystem
|
||||
#
|
||||
class _FilesystemImporter(Importer):
|
||||
def __init__(self, suffixes):
|
||||
# this list is shared with the ImportManager.
|
||||
self.suffixes = suffixes
|
||||
|
||||
def import_from_dir(self, dir, fqname):
|
||||
result = self._import_pathname(_os_path_join(dir, fqname), fqname)
|
||||
if result:
|
||||
return self._process_result(result, fqname)
|
||||
return None
|
||||
|
||||
def get_code(self, parent, modname, fqname):
|
||||
# This importer is never used with an empty parent. Its existence is
|
||||
# private to the ImportManager. The ImportManager uses the
|
||||
# import_from_dir() method to import top-level modules/packages.
|
||||
# This method is only used when we look for a module within a package.
|
||||
assert parent
|
||||
|
||||
return self._import_pathname(_os_path_join(parent.__pkgdir__, modname),
|
||||
fqname)
|
||||
|
||||
def _import_pathname(self, pathname, fqname):
|
||||
if _os_path_isdir(pathname):
|
||||
result = self._import_pathname(_os_path_join(pathname, '__init__'),
|
||||
fqname)
|
||||
if result:
|
||||
values = result[2]
|
||||
values['__pkgdir__'] = pathname
|
||||
values['__path__'] = [ pathname ]
|
||||
return 1, result[1], values
|
||||
return None
|
||||
|
||||
for suffix, importer in self.suffixes:
|
||||
filename = pathname + suffix
|
||||
try:
|
||||
finfo = _os_stat(filename)
|
||||
except OSError:
|
||||
pass
|
||||
else:
|
||||
return importer.import_file(filename, finfo, fqname)
|
||||
return None
|
||||
|
||||
######################################################################
|
||||
#
|
||||
# SUFFIX-BASED IMPORTERS
|
||||
#
|
||||
|
||||
class SuffixImporter:
|
||||
def import_file(self, filename, finfo, fqname):
|
||||
raise RuntimeError
|
||||
|
||||
class PySuffixImporter(SuffixImporter):
|
||||
def import_file(self, filename, finfo, fqname):
|
||||
file = filename[:-3] + _suffix
|
||||
t_py = long(finfo[8])
|
||||
t_pyc = _timestamp(file)
|
||||
|
||||
code = None
|
||||
if t_pyc is not None and t_pyc >= t_py:
|
||||
f = open(file, 'rb')
|
||||
if f.read(4) == imp.get_magic():
|
||||
t = struct.unpack('<I', f.read(4))[0]
|
||||
if t == t_py:
|
||||
code = marshal.load(f)
|
||||
f.close()
|
||||
if code is None:
|
||||
file = filename
|
||||
code = _compile(file, t_py)
|
||||
|
||||
return 0, code, { '__file__' : file }
|
||||
|
||||
class DynLoadSuffixImporter(SuffixImporter):
|
||||
def __init__(self, desc):
|
||||
self.desc = desc
|
||||
|
||||
def import_file(self, filename, finfo, fqname):
|
||||
fp = open(filename, self.desc[1])
|
||||
module = imp.load_module(fqname, fp, filename, self.desc)
|
||||
module.__file__ = filename
|
||||
return 0, module, { }
|
||||
|
||||
|
||||
######################################################################
|
||||
|
||||
def _test_dir():
|
||||
|
|
@ -675,4 +813,8 @@ def _print_importers():
|
|||
else:
|
||||
print name, '-- non-existent module'
|
||||
|
||||
def _test_revamp():
|
||||
ImportManager().install()
|
||||
sys.path.insert(0, BuiltinImporter())
|
||||
|
||||
######################################################################
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue