FM / imputil

/usr/lib64/python2.6/Demo/imputil

Name	Size	Mode	Actions
importers.py	7811	0644	edit dl rm
importers.pyc	8361	0644	edit dl rm
importers.pyo	8259	0644	edit dl rm
knee.py	3482	0644	edit dl rm
knee.pyc	3777	0644	edit dl rm
knee.pyo	3690	0644	edit dl rm

Edit: /usr/lib64/python2.6/Demo/imputil/importers.py (7811B)

#
# importers.py
#
# Demonstration subclasses of imputil.Importer
#

# There should be consideration for the imports below if it is desirable
# to have "all" modules be imported through the imputil system.

# these are C extensions
import sys
import imp
import struct
import marshal

# these are .py modules
import imputil
import os

######################################################################

_TupleType = type(())
_StringType = type('')

######################################################################

# byte-compiled file suffic character
_suffix_char = __debug__ and 'c' or 'o'

# byte-compiled file suffix
_suffix = '.py' + _suffix_char

# the C_EXTENSION suffixes
_c_suffixes = filter(lambda x: x[2] == imp.C_EXTENSION, imp.get_suffixes())

def _timestamp(pathname):
    "Return the file modification time as a Long."
    try:
        s = os.stat(pathname)
    except OSError:
        return None
    return long(s[8])

def _fs_import(dir, modname, fqname):
    "Fetch a module from the filesystem."

pathname = os.path.join(dir, modname)
    if os.path.isdir(pathname):
        values = { '__pkgdir__' : pathname, '__path__' : [ pathname ] }
        ispkg = 1
        pathname = os.path.join(pathname, '__init__')
    else:
        values = { }
        ispkg = 0

# look for dynload modules
        for desc in _c_suffixes:
            file = pathname + desc[0]
            try:
                fp = open(file, desc[1])
            except IOError:
                pass
            else:
                module = imp.load_module(fqname, fp, file, desc)
                values['__file__'] = file
                return 0, module, values

t_py = _timestamp(pathname + '.py')
    t_pyc = _timestamp(pathname + _suffix)
    if t_py is None and t_pyc is None:
        return None
    code = None
    if t_py is None or (t_pyc is not None and t_pyc >= t_py):
        file = pathname + _suffix
        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 = pathname + '.py'
        code = _compile(file, t_py)

values['__file__'] = file
    return ispkg, code, values

######################################################################
#
# Simple function-based importer
#
class FuncImporter(imputil.Importer):
    "Importer subclass to delegate to a function rather than method overrides."
    def __init__(self, func):
        self.func = func
    def get_code(self, parent, modname, fqname):
        return self.func(parent, modname, fqname)

def install_with(func):
    FuncImporter(func).install()

######################################################################
#
# Base class for archive-based importing
#
class PackageArchiveImporter(imputil.Importer):
    """Importer subclass to import from (file) archives.

This Importer handles imports of the style <archive>.<subfile>, where
    <archive> can be located using a subclass-specific mechanism and the
    <subfile> is found in the archive using a subclass-specific mechanism.

This class defines two hooks for subclasses: one to locate an archive
    (and possibly return some context for future subfile lookups), and one
    to locate subfiles.
    """

def get_code(self, parent, modname, fqname):
        if parent:
            # the Importer._finish_import logic ensures that we handle imports
            # under the top level module (package / archive).
            assert parent.__importer__ == self

# if a parent "package" is provided, then we are importing a
            # sub-file from the archive.
            result = self.get_subfile(parent.__archive__, modname)
            if result is None:
                return None
            if isinstance(result, _TupleType):
                assert len(result) == 2
                return (0,) + result
            return 0, result, {}

# no parent was provided, so the archive should exist somewhere on the
        # default "path".
        archive = self.get_archive(modname)
        if archive is None:
            return None
        return 1, "", {'__archive__':archive}

def get_archive(self, modname):
        """Get an archive of modules.

This method should locate an archive and return a value which can be
        used by get_subfile to load modules from it. The value may be a simple
        pathname, an open file, or a complex object that caches information
        for future imports.

Return None if the archive was not found.
        """
        raise RuntimeError, "get_archive not implemented"

def get_subfile(self, archive, modname):
        """Get code from a subfile in the specified archive.

Given the specified archive (as returned by get_archive()), locate
        and return a code object for the specified module name.

A 2-tuple may be returned, consisting of a code object and a dict
        of name/values to place into the target module.

Return None if the subfile was not found.
        """
        raise RuntimeError, "get_subfile not implemented"

class PackageArchive(PackageArchiveImporter):
    "PackageArchiveImporter subclass that refers to a specific archive."

def __init__(self, modname, archive_pathname):
        self.__modname = modname
        self.__path = archive_pathname

def get_archive(self, modname):
        if modname == self.__modname:
            return self.__path
        return None

# get_subfile is passed the full pathname of the archive

######################################################################
#
# Emulate the standard directory-based import mechanism
#
class DirectoryImporter(imputil.Importer):
    "Importer subclass to emulate the standard importer."

def __init__(self, dir):
        self.dir = dir

def get_code(self, parent, modname, fqname):
        if parent:
            dir = parent.__pkgdir__
        else:
            dir = self.dir

# Return the module (and other info) if found in the specified
        # directory. Otherwise, return None.
        return _fs_import(dir, modname, fqname)

def __repr__(self):
        return '<%s.%s for "%s" at 0x%x>' % (self.__class__.__module__,
                                             self.__class__.__name__,
                                             self.dir,
                                             id(self))

######################################################################
#
# Emulate the standard path-style import mechanism
#
class PathImporter(imputil.Importer):
    def __init__(self, path=sys.path):
        self.path = path

def get_code(self, parent, modname, fqname):
        if parent:
            # we are looking for a module inside of a specific package
            return _fs_import(parent.__pkgdir__, modname, fqname)

# scan sys.path, looking for the requested module
        for dir in self.path:
            if isinstance(dir, _StringType):
                result = _fs_import(dir, modname, fqname)
                if result:
                    return result

# not found
        return None

######################################################################

def _test_dir():
    "Debug/test function to create DirectoryImporters from sys.path."
    imputil.ImportManager().install()
    path = sys.path[:]
    path.reverse()
    for d in path:
        sys.path.insert(0, DirectoryImporter(d))
    sys.path.insert(0, imputil.BuiltinImporter())

def _test_revamp():
    "Debug/test function for the revamped import system."
    imputil.ImportManager().install()
    sys.path.insert(0, PathImporter())
    sys.path.insert(0, imputil.BuiltinImporter())

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