[Scons-dev] Contribution to SCons development.

[Gary Oberbrunner]

On Sat, Dec 6, 2014 at 1:03 PM, <alexandre.feblot at gmail.com> wrote:

> I found one here:
> http://computer-programming-forum.com/56-python/46da865fb41a1dc3.htm
>
> Ansible worked on that as well:
> https://github.com/ansible/ansible/blob/devel/lib/ansible/module_utils/basic.py
>
> (_symbolic_mode_to_octal, _apply_operation_to_mode, _get_octal_mode_from_symbolic_perms)
>

Good detective work!  The second is a bit more modern in style, but they
both seem workable.

-- Gary


>
>
> Le 6 déc. 2014 à 16:24, Gary Oberbrunner <garyo at oberbrunner.com> a écrit :
>
>
>
> On Sat, Dec 6, 2014 at 9:37 AM, Shreedhar Manek <shreedharmanek at gmail.com>
> wrote:
>
>> 256 is octal 0400, so it looks like it's only getting the S_IRUSR part.
>>>> And that's because I steered you wrong; these are bitmasks, so you have to
>>>> use bitwise OR:  S_IRUSR | S_IRGRP | S_IROTH
>>>>
>>>
>> This was it. Thanks!
>>
>> Should I replace *all *integers with their counterpart string? Or only
>> select ones?
>>
>
> Well, first, don't forget your real goal is to allow SCons users to
> actually use a *string* to set the mode bits.  These constants you're
> using are in the 'stat' module (so 'import stat' will fix your bug below),
> but they are still numeric absolute constants.
>
> I think the original issue (
> http://scons.tigris.org/issues/show_bug.cgi?id=2494) asks for allowing
> users to use actual strings like the chmod command-line utility, which
> allows relative modes like "ug+rw,o-rwx" as well as numeric absolute modes
> like "777" (that's still a string, note). (see the chmod man page, for
> instance http://linux.die.net/man/1/chmod.)  SCons users could already
> just do 'import stat' and use the named constants, but those are absolute;
> the desired chmod modes are *relative *to the current state.  The main
> task for this issue is, I think, to parse those relative modes (relative to
> the file's current state) and compute the desired final mode.
>
> If you can write a function parse_mode_string(mode_string,
> original_mode_bits), that's 90% of the work.  (Actually I'm surprised there
> isn't one already written out there somewhere.)
>
> -- Gary
>
>
>> Replacing the first 0777 with S_IRWXU | S_IRWXG | S_IRWXO in
>>
>> test.write('SConstruct', """
>> Execute(Chmod('f1', 0666))
>> Execute(Chmod(('f1-File'), 0666))
>> Execute(Chmod('d2', S_IRWXU | S_IRWXG | S_IRWXO))
>> Execute(Chmod(Dir('d2-Dir'), 0777))
>> def cat(env, source, target):
>>     target = str(target[0])
>>     f = open(target, "wb")
>>     for src in source:
>>         f.write(open(str(src), "rb").read())
>>     f.close()
>> Cat = Action(cat)
>> env = Environment()
>> env.Command('bar.out', 'bar.in', [Cat,
>>                                   Chmod("f3", 0666),
>>                                   Chmod("d4", 0777)])
>> env = Environment(FILE = 'f5')
>> env.Command('f6.out', 'f6.in', [Chmod('$FILE', 0666), Cat])
>> env.Command('f7.out', 'f7.in', [Cat,
>>                                 Chmod('Chmod-$SOURCE', 0666),
>>                                 Chmod('${TARGET}-Chmod', 0666)])
>>
>> # Make sure Chmod works with a list of arguments
>> env = Environment(FILE = 'f9')
>> env.Command('f8.out', 'f8.in', [Chmod(['$FILE', File('f10')], 0666),
>> Cat])
>> Execute(Chmod(['d11', Dir('d12')], 0777))
>> """)
>>
>> gives the following error,
>>
>> STDERR
>> =========================================================================
>> NameError: name 'S_IRWXU' is not defined:
>>   File "/tmp/testcmd.23013.se_zJm/SConstruct", line 4:
>>     Execute(Chmod('d2', S_IRWXU | S_IRWXG | S_IRWXO))
>>
>> FAILED test of /home/shrox/scons/src/script/scons.py
>> at line 598 of /home/shrox/scons/QMTest/TestCommon.py (_complete)
>> from line 701 of /home/shrox/scons/QMTest/TestCommon.py (run)
>> from line 390 of /home/shrox/scons/QMTest/TestSCons.py (run)
>> from line 123 of test/Chmod.py
>>
>>
>>
>> --
>> Shreedhar Manek
>>
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>> Scons-dev at scons.org
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>>
>>
>
>
> --
> Gary
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>


-- 
Gary
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