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# Copyright (c) 2001 by Intevation GmbH |
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# Authors: |
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# Bernhard Herzog <[email protected]> |
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# |
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# This program is free software under the GPL (>=v2) |
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# Read the file COPYING coming with Thuban for details. |
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|
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""" |
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Functions to deal with filenames |
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""" |
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|
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__version__ = "$Revision$" |
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|
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import os.path |
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from string import split, join |
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|
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|
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def relative_filename_common(dir, absname, sep): |
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"""Return a filename relative to dir for the absolute file name absname. |
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This is part the posix and nt versions have in common. Both dir and |
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absname are assumed to be normalized (as done with os.normpath) |
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absolute filenames without drive letters. sep is the platform |
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specific directory separator. |
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""" |
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|
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# split the filenames into their components. remove the first item |
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# since it will be always empty because both names are absolute. |
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dir_parts = split(dir, sep)[1:] |
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absname_parts = split(absname, sep)[1:] |
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|
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# count the number of common parts at the start of dir_parts and |
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# absname_parts |
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max_common = min(len(dir_parts), len(absname_parts)) |
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common = 0 |
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while common < max_common and dir_parts[common] == absname_parts[common]: |
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common = common + 1 |
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|
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# If the common part is the root directory, return absname |
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if common == 0: |
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return absname |
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|
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# for each directory under the common part prepend a '..'. |
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rel_parts = (len(dir_parts) - common) * ['..'] + absname_parts[common:] |
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return join(rel_parts, sep) |
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|
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|
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def relative_filename_posix(dir, absname): |
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"""Return a filename relative to dir for the absolute file name absname. |
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|
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If absname is already a relative filename, return it unchanged. If |
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the common directory of dir and absname is /, return absname |
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unchanged. If dir is not an absolute name, raise TypeError. |
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|
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This is the posix specific version of relative_filename. |
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|
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Example: |
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>>> from fileutil import relative_filename_posix |
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>>> relative_filename_posix("/usr/local/lib/", "/usr/local/lib/python") |
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'python' |
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>>> relative_filename_posix("/usr/local/lib/", "/usr/local/bin/python") |
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'../bin/python' |
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>>> relative_filename_posix("/usr/local/lib/", "/usr/bin/python") |
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'../../bin/python' |
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>>> relative_filename_posix("/usr/local/lib/", "/var/spool/mail") |
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'/var/spool/mail' |
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>>> relative_filename_posix("/home/", "xyzzy") |
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'xyzzy' |
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>>> relative_filename_posix("home/", "/xyzzy") |
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Traceback (most recent call last): |
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File "<stdin>", line 1, in ? |
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File "fileutil.py", line 42, in relative_filename_posix |
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raise TypeError("first argument must be an absolute filename") |
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TypeError: first argument must be an absolute filename |
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""" |
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# for posix, the common part does exactly what we need, except for |
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# the special cases and input checking. Import posixpath explicitly |
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# for that to faciliate testing |
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import posixpath |
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if not posixpath.isabs(absname): |
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return absname |
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|
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if not posixpath.isabs(dir): |
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raise TypeError("first argument must be an absolute filename") |
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|
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dir = posixpath.normpath(dir) |
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absname = posixpath.normpath(absname) |
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|
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return relative_filename_common(dir, absname, "/") |
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|
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def relative_filename_nt(dir, absname): |
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r"""Return a filename relative to dir for the absolute file name absname. |
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|
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If absname is already a relative filename or if dir and absname are |
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on different drives, return absname. If the common directory of dir |
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and absname is the drive's root directory, return absname. If dir is |
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not an absolute name or either name doesn't have a drive letter, |
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raise TypeError. |
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|
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This is the nt specific version of relative_filename. |
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|
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Example: |
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>>> from fileutil import relative_filename_nt |
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>>> relative_filename_nt(r"C:\Programme\Python", r"C:\Programme\Thuban") |
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'..\\Thuban' |
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>>> relative_filename_nt(r"C:\Programme\Python", r"D:\Programme\Thuban") |
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'D:\\Programme\\Thuban' |
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>>> relative_filename_nt(r"C:\Programme\Python", r"C:Programme") |
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'C:Programme' |
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>>> relative_filename_nt(r"C:Programme\Python", r"C:Programme") |
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Traceback (most recent call last): |
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File "<stdin>", line 1, in ? |
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File "fileutil.py", line 123, in relative_filename_nt |
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raise TypeError("first argument must be an absolute filename") |
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TypeError: first argument must be an absolute filename |
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>>> relative_filename_nt(r"\Programme\Python", r"\Programme") |
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Traceback (most recent call last): |
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File "<stdin>", line 1, in ? |
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File "fileutil.py", line 120, in relative_filename_nt |
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raise TypeError("Both parameters must have a drive letter") |
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TypeError: Both parameters must have a drive letter |
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""" |
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# first check the parameters. Imort ntpath directly to facilitate |
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# testing on non-nt systems. |
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import ntpath |
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|
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dir = ntpath.normpath(dir) |
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absname = ntpath.normpath(absname) |
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|
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dir_drive, dir_rest = ntpath.splitdrive(dir) |
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absname_drive, absname_rest = ntpath.splitdrive(absname) |
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#print dir_drive, dir_rest |
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#print absname_drive, absname_rest |
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if not dir_drive or not absname_drive: |
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raise TypeError("Both parameters must have a drive letter") |
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|
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if not ntpath.isabs(dir_rest): |
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raise TypeError("first argument must be an absolute filename") |
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|
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# handle some special cases |
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if not ntpath.isabs(absname_rest): |
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return absname |
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|
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if dir_drive != absname_drive: |
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return absname |
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|
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# Now both dir_rest and absname_rest are absolute filenames without |
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# drive letter. We can now use the common part to determine the |
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# relative name |
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return relative_filename_common(dir_rest, absname_rest, "\\") |
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|
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|
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# bind the appriate version of relative_filename for the platform we're |
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# currently running on. |
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if os.name == "posix": |
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relative_filename = relative_filename_posix |
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elif os.name == "nt": |
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relative_filename = relative_filename_nt |
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else: |
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raise RuntimeError("No implementation of relative_filename" |
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" available for platform" + os.name) |
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|
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__test__ = {"relative_filename_posix": relative_filename_posix, |
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"relative_filename_nt": relative_filename_nt} |
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|
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# if run as a script, run doctest |
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def _test(): |
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import doctest, fileutil |
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# Pass an isprivate function that always returns true so that only |
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# items in __test__ are tested |
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return doctest.testmod(fileutil, isprivate = lambda *args: 1) |
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|
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if __name__ == "__main__": |
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_test() |
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