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719 lines
25 KiB
719 lines
25 KiB
""" |
|
Import utilities |
|
|
|
Exported classes: |
|
ImportManager Manage the import process |
|
|
|
Importer Base class for replacing standard import functions |
|
BuiltinImporter Emulate the import mechanism for builtin and frozen modules |
|
|
|
DynLoadSuffixImporter |
|
""" |
|
|
|
# note: avoid importing non-builtin modules |
|
import imp ### not available in JPython? |
|
import sys |
|
import __builtin__ |
|
|
|
# for the DirectoryImporter |
|
import struct |
|
import marshal |
|
|
|
__all__ = ["ImportManager","Importer","BuiltinImporter"] |
|
|
|
_StringType = type('') |
|
_ModuleType = type(sys) ### doesn't work in JPython... |
|
|
|
class ImportManager: |
|
"Manage the import process." |
|
|
|
def install(self, namespace=vars(__builtin__)): |
|
"Install this ImportManager into the specified namespace." |
|
|
|
if isinstance(namespace, _ModuleType): |
|
namespace = vars(namespace) |
|
|
|
# Note: we have no notion of "chaining" |
|
|
|
# Record the previous import hook, then install our own. |
|
self.previous_importer = namespace['__import__'] |
|
self.namespace = namespace |
|
namespace['__import__'] = self._import_hook |
|
|
|
### fix this |
|
#namespace['reload'] = self._reload_hook |
|
|
|
def uninstall(self): |
|
"Restore the previous import mechanism." |
|
self.namespace['__import__'] = self.previous_importer |
|
|
|
def add_suffix(self, suffix, importFunc): |
|
assert callable(importFunc) |
|
self.fs_imp.add_suffix(suffix, importFunc) |
|
|
|
###################################################################### |
|
# |
|
# PRIVATE METHODS |
|
# |
|
|
|
clsFilesystemImporter = None |
|
|
|
def __init__(self, fs_imp=None): |
|
# 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 is the Importer that we use for grabbing stuff from the |
|
# filesystem. It defines one more method (import_from_dir) for our use. |
|
if fs_imp is None: |
|
cls = self.clsFilesystemImporter or _FilesystemImporter |
|
fs_imp = cls() |
|
self.fs_imp = fs_imp |
|
|
|
# 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) |
|
for desc in imp.get_suffixes(): |
|
if desc[2] == imp.C_EXTENSION: |
|
self.add_suffix(desc[0], |
|
DynLoadSuffixImporter(desc).import_file) |
|
self.add_suffix('.py', py_suffix_importer) |
|
|
|
def _import_hook(self, fqname, globals=None, locals=None, fromlist=None): |
|
"""Python calls this hook to locate and import a module.""" |
|
|
|
parts = fqname.split('.') |
|
|
|
# determine the context of this import |
|
parent = self._determine_import_context(globals) |
|
|
|
# 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 |
|
|
|
# fast-path simple imports |
|
if len(parts) == 1: |
|
if not fromlist: |
|
return top_module |
|
|
|
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) |
|
|
|
# Grrr, some people "import os.path" |
|
if len(parts) == 2 and hasattr(top_module, parts[1]): |
|
return top_module |
|
|
|
# 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 |
|
|
|
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 = parent_fqname.rfind('.') |
|
|
|
# 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 isinstance(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: |
|
### oops. now what... |
|
pass |
|
|
|
# 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 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, 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. |
|
# |
|
# 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 use __ispkg__). |
|
|
|
# if the bottom node is a package, then (potentially) import some |
|
# modules. |
|
# |
|
# note: if it is not a package, then "fromlist" refers to names in |
|
# the bottom module rather than modules. |
|
# note: for a mix of names and modules in the fromlist, we will |
|
# import all modules and insert those into the namespace of |
|
# the package module. Python will pick up all fromlist names |
|
# 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 bottom.__ispkg__: |
|
self._import_fromlist(bottom, fromlist) |
|
|
|
# if the form is "from a.b import c, d" then return "b" |
|
return bottom |
|
|
|
def _import_one(self, parent, modname, fqname): |
|
"Import a single module." |
|
|
|
# has the module already been imported? |
|
try: |
|
return sys.modules[fqname] |
|
except KeyError: |
|
pass |
|
|
|
# load the module's code, or fetch the module itself |
|
result = self.get_code(parent, modname, fqname) |
|
if result is None: |
|
return None |
|
|
|
module = self._process_result(result, fqname) |
|
|
|
# insert the module into its parent |
|
if parent: |
|
setattr(parent, modname, module) |
|
return module |
|
|
|
def _process_result(self, (ispkg, code, values), fqname): |
|
# did get_code() return an actual module? (rather than a code object) |
|
is_module = isinstance(code, _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__ |
|
|
|
# fetch from sys.modules instead of returning module directly. |
|
# also make module's __name__ agree with fqname, in case |
|
# the "exec code in module.__dict__" played games on us. |
|
module = sys.modules[fqname] |
|
module.__name__ = fqname |
|
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. |
|
""" |
|
for part in parts: |
|
fqname = "%s.%s" % (m.__name__, part) |
|
m = self._import_one(m, part, fqname) |
|
if not m: |
|
raise ImportError, "No module named " + fqname |
|
return m |
|
|
|
def _import_fromlist(self, package, fromlist): |
|
'Import any sub-modules in the "from" list.' |
|
|
|
# if '*' is present in the fromlist, then look for the '__all__' |
|
# variable to find additional items (modules) to import. |
|
if '*' in fromlist: |
|
fromlist = list(fromlist) + \ |
|
list(package.__dict__.get('__all__', [])) |
|
|
|
for sub in fromlist: |
|
# if the name is already present, then don't try to import it (it |
|
# might not be a module!). |
|
if sub != '*' and not hasattr(package, sub): |
|
subname = "%s.%s" % (package.__name__, sub) |
|
submod = self._import_one(package, sub, subname) |
|
if not submod: |
|
raise ImportError, "cannot import name " + subname |
|
|
|
def _do_import(self, parent, parts, fromlist): |
|
"""Attempt to import the module relative to parent. |
|
|
|
This method is used when the import context specifies that <self> |
|
imported the parent module. |
|
""" |
|
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) |
|
|
|
###################################################################### |
|
# |
|
# METHODS TO OVERRIDE |
|
# |
|
def get_code(self, parent, modname, fqname): |
|
"""Find and retrieve the code for the given module. |
|
|
|
parent specifies a parent module to define a context for importing. It |
|
may be None, indicating no particular context for the search. |
|
|
|
modname specifies a single module (not dotted) within the parent. |
|
|
|
fqname specifies the fully-qualified module name. This is a |
|
(potentially) 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, or a 3-tuple. |
|
|
|
* If the module was not found, then None should be returned. |
|
|
|
* The first item of the 2- or 3-tuple should be the integer 0 or 1, |
|
specifying whether the module that was found is a package or not. |
|
|
|
* The second item is the code object for the module (it will be |
|
executed within the new module's namespace). This item can also |
|
be a fully-loaded module object (e.g. loaded from a shared lib). |
|
|
|
* 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. |
|
""" |
|
raise RuntimeError, "get_code not implemented" |
|
|
|
|
|
###################################################################### |
|
# |
|
# Some handy stuff for the Importers |
|
# |
|
|
|
# byte-compiled file suffix character |
|
_suffix_char = __debug__ and 'c' or 'o' |
|
|
|
# byte-compiled file suffix |
|
_suffix = '.py' + _suffix_char |
|
|
|
def _compile(pathname, timestamp): |
|
"""Compile (and cache) a Python source file. |
|
|
|
The file specified by <pathname> is compiled to a code object and |
|
returned. |
|
|
|
Presuming the appropriate privileges exist, the bytecodes will be |
|
saved back to the filesystem for future imports. The source file's |
|
modification timestamp must be provided as a Long value. |
|
""" |
|
codestring = open(pathname, 'rU').read() |
|
if codestring and codestring[-1] != '\n': |
|
codestring = codestring + '\n' |
|
code = __builtin__.compile(codestring, pathname, 'exec') |
|
|
|
# try to cache the compiled code |
|
try: |
|
f = open(pathname + _suffix_char, 'wb') |
|
except IOError: |
|
pass |
|
else: |
|
f.write('\0\0\0\0') |
|
f.write(struct.pack('<I', timestamp)) |
|
marshal.dump(code, f) |
|
f.flush() |
|
f.seek(0, 0) |
|
f.write(imp.get_magic()) |
|
f.close() |
|
|
|
return code |
|
|
|
_os_stat = _os_path_join = None |
|
def _os_bootstrap(): |
|
"Set up 'os' module replacement functions for use during import bootstrap." |
|
|
|
names = sys.builtin_module_names |
|
|
|
join = None |
|
if 'posix' in names: |
|
sep = '/' |
|
from posix import stat |
|
elif 'nt' in names: |
|
sep = '\\' |
|
from nt import stat |
|
elif 'dos' in names: |
|
sep = '\\' |
|
from dos import stat |
|
elif 'os2' in names: |
|
sep = '\\' |
|
from os2 import stat |
|
elif 'mac' in names: |
|
from mac import stat |
|
def join(a, b): |
|
if a == '': |
|
return b |
|
if ':' not in a: |
|
a = ':' + a |
|
if a[-1:] != ':': |
|
a = a + ':' |
|
return a + b |
|
else: |
|
raise ImportError, 'no os specific module found' |
|
|
|
if join is None: |
|
def join(a, b, sep=sep): |
|
if a == '': |
|
return b |
|
lastchar = a[-1:] |
|
if lastchar == '/' or lastchar == sep: |
|
return a + b |
|
return a + sep + b |
|
|
|
global _os_stat |
|
_os_stat = stat |
|
|
|
global _os_path_join |
|
_os_path_join = join |
|
|
|
def _os_path_isdir(pathname): |
|
"Local replacement for os.path.isdir()." |
|
try: |
|
s = _os_stat(pathname) |
|
except OSError: |
|
return None |
|
return (s.st_mode & 0170000) == 0040000 |
|
|
|
def _timestamp(pathname): |
|
"Return the file modification time as a Long." |
|
try: |
|
s = _os_stat(pathname) |
|
except OSError: |
|
return None |
|
return long(s.st_mtime) |
|
|
|
|
|
###################################################################### |
|
# |
|
# Emulate the import mechanism for builtin and frozen modules |
|
# |
|
class BuiltinImporter(Importer): |
|
def get_code(self, parent, modname, fqname): |
|
if parent: |
|
# these modules definitely do not occur within a package context |
|
return None |
|
|
|
# look for the module |
|
if imp.is_builtin(modname): |
|
type = imp.C_BUILTIN |
|
elif imp.is_frozen(modname): |
|
type = imp.PY_FROZEN |
|
else: |
|
# not found |
|
return None |
|
|
|
# got it. now load and return it. |
|
module = imp.load_module(modname, None, modname, ('', '', type)) |
|
return 0, module, { } |
|
|
|
|
|
###################################################################### |
|
# |
|
# Internal importer used for importing from the filesystem |
|
# |
|
class _FilesystemImporter(Importer): |
|
def __init__(self): |
|
self.suffixes = [ ] |
|
|
|
def add_suffix(self, suffix, importFunc): |
|
assert callable(importFunc) |
|
self.suffixes.append((suffix, importFunc)) |
|
|
|
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, importFunc in self.suffixes: |
|
filename = pathname + suffix |
|
try: |
|
finfo = _os_stat(filename) |
|
except OSError: |
|
pass |
|
else: |
|
return importFunc(filename, finfo, fqname) |
|
return None |
|
|
|
###################################################################### |
|
# |
|
# SUFFIX-BASED IMPORTERS |
|
# |
|
|
|
def py_suffix_importer(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: |
|
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 _print_importers(): |
|
items = sys.modules.items() |
|
items.sort() |
|
for name, module in items: |
|
if module: |
|
print name, module.__dict__.get('__importer__', '-- no importer') |
|
else: |
|
print name, '-- non-existent module' |
|
|
|
def _test_revamp(): |
|
ImportManager().install() |
|
sys.path.insert(0, BuiltinImporter()) |
|
|
|
###################################################################### |
|
|
|
# |
|
# TODO |
|
# |
|
# from Finn Bock: |
|
# type(sys) is not a module in JPython. what to use instead? |
|
# imp.C_EXTENSION is not in JPython. same for get_suffixes and new_module |
|
# |
|
# given foo.py of: |
|
# import sys |
|
# sys.modules['foo'] = sys |
|
# |
|
# ---- standard import mechanism |
|
# >>> import foo |
|
# >>> foo |
|
# <module 'sys' (built-in)> |
|
# |
|
# ---- revamped import mechanism |
|
# >>> import imputil |
|
# >>> imputil._test_revamp() |
|
# >>> import foo |
|
# >>> foo |
|
# <module 'foo' from 'foo.py'> |
|
# |
|
# |
|
# from MAL: |
|
# should BuiltinImporter exist in sys.path or hard-wired in ImportManager? |
|
# need __path__ processing |
|
# performance |
|
# move chaining to a subclass [gjs: it's been nuked] |
|
# deinstall should be possible |
|
# query mechanism needed: is a specific Importer installed? |
|
# py/pyc/pyo piping hooks to filter/process these files |
|
# wish list: |
|
# distutils importer hooked to list of standard Internet repositories |
|
# module->file location mapper to speed FS-based imports |
|
# relative imports |
|
# keep chaining so that it can play nice with other import hooks |
|
# |
|
# from Gordon: |
|
# push MAL's mapper into sys.path[0] as a cache (hard-coded for apps) |
|
# |
|
# from Guido: |
|
# need to change sys.* references for rexec environs |
|
# need hook for MAL's walk-me-up import strategy, or Tim's absolute strategy |
|
# watch out for sys.modules[...] is None |
|
# flag to force absolute imports? (speeds _determine_import_context and |
|
# checking for a relative module) |
|
# insert names of archives into sys.path (see quote below) |
|
# note: reload does NOT blast module dict |
|
# shift import mechanisms and policies around; provide for hooks, overrides |
|
# (see quote below) |
|
# add get_source stuff |
|
# get_topcode and get_subcode |
|
# CRLF handling in _compile |
|
# race condition in _compile |
|
# refactoring of os.py to deal with _os_bootstrap problem |
|
# any special handling to do for importing a module with a SyntaxError? |
|
# (e.g. clean up the traceback) |
|
# implement "domain" for path-type functionality using pkg namespace |
|
# (rather than FS-names like __path__) |
|
# don't use the word "private"... maybe "internal" |
|
# |
|
# |
|
# Guido's comments on sys.path caching: |
|
# |
|
# We could cache this in a dictionary: the ImportManager can have a |
|
# cache dict mapping pathnames to importer objects, and a separate |
|
# method for coming up with an importer given a pathname that's not yet |
|
# in the cache. The method should do a stat and/or look at the |
|
# extension to decide which importer class to use; you can register new |
|
# importer classes by registering a suffix or a Boolean function, plus a |
|
# class. If you register a new importer class, the cache is zapped. |
|
# The cache is independent from sys.path (but maintained per |
|
# ImportManager instance) so that rearrangements of sys.path do the |
|
# right thing. If a path is dropped from sys.path the corresponding |
|
# cache entry is simply no longer used. |
|
# |
|
# My/Guido's comments on factoring ImportManager and Importer: |
|
# |
|
# > However, we still have a tension occurring here: |
|
# > |
|
# > 1) implementing policy in ImportManager assists in single-point policy |
|
# > changes for app/rexec situations |
|
# > 2) implementing policy in Importer assists in package-private policy |
|
# > changes for normal, operating conditions |
|
# > |
|
# > I'll see if I can sort out a way to do this. Maybe the Importer class will |
|
# > implement the methods (which can be overridden to change policy) by |
|
# > delegating to ImportManager. |
|
# |
|
# Maybe also think about what kind of policies an Importer would be |
|
# likely to want to change. I have a feeling that a lot of the code |
|
# there is actually not so much policy but a *necessity* to get things |
|
# working given the calling conventions for the __import__ hook: whether |
|
# to return the head or tail of a dotted name, or when to do the "finish |
|
# fromlist" stuff. |
|
#
|
|
|