mirror of https://github.com/python/cpython
68 lines
2.4 KiB
Python
68 lines
2.4 KiB
Python
# This module provides standard support for "packages".
|
|
#
|
|
# The idea is that large groups of related modules can be placed in
|
|
# their own subdirectory, which can be added to the Python search path
|
|
# in a relatively easy way.
|
|
#
|
|
# The current version takes a package name and searches the Python
|
|
# search path for a directory by that name, and if found adds it to
|
|
# the module search path (sys.path). It maintains a list of packages
|
|
# that have already been added so adding the same package many times
|
|
# is OK.
|
|
#
|
|
# It is intended to be used in a fairly stylized manner: each module
|
|
# that wants to use a particular package, say 'Foo', is supposed to
|
|
# contain the following code:
|
|
#
|
|
# from addpack import addpack
|
|
# addpack('Foo')
|
|
# <import modules from package Foo>
|
|
#
|
|
# Additional arguments, when present, provide additional places where
|
|
# to look for the package before trying sys.path (these may be either
|
|
# strings or lists/tuples of strings). Also, if the package name is a
|
|
# full pathname, first the last component is tried in the usual way,
|
|
# then the full pathname is tried last. If the package name is a
|
|
# *relative* pathname (UNIX: contains a slash but doesn't start with
|
|
# one), then nothing special is done. The packages "/foo/bar/bletch"
|
|
# and "bletch" are considered the same, but unrelated to "bar/bletch".
|
|
#
|
|
# If the algorithm finds more than one suitable subdirectory, all are
|
|
# added to the search path -- this makes it possible to override part
|
|
# of a package. The same path will not be added more than once.
|
|
#
|
|
# If no directory is found, ImportError is raised.
|
|
|
|
_packs = {} # {pack: [pathname, ...], ...}
|
|
|
|
def addpack(pack, *locations):
|
|
import os
|
|
if os.path.isabs(pack):
|
|
base = os.path.basename(pack)
|
|
else:
|
|
base = pack
|
|
if _packs.has_key(base):
|
|
return
|
|
import sys
|
|
path = []
|
|
for loc in _flatten(locations) + sys.path:
|
|
fn = os.path.join(loc, base)
|
|
if fn not in path and os.path.isdir(fn):
|
|
path.append(fn)
|
|
if pack != base and pack not in path and os.path.isdir(pack):
|
|
path.append(pack)
|
|
if not path: raise ImportError, 'package ' + pack + ' not found'
|
|
_packs[base] = path
|
|
for fn in path:
|
|
if fn not in sys.path:
|
|
sys.path.append(fn)
|
|
|
|
def _flatten(locations):
|
|
locs = []
|
|
for loc in locations:
|
|
if type(loc) == type(''):
|
|
locs.append(loc)
|
|
else:
|
|
locs = locs + _flatten(loc)
|
|
return locs
|