[Fontconfig] Re: weird crash with fontconfig 2.3.92

[Mike FABIAN]

Mike FABIAN <mfabian at suse.de> さんは書きました:

> Mike FABIAN <mfabian at suse.de> さんは書きました:
>
>> mfabian at magellan:~$ fc-match "foo:\\_\\_DUMMY\\_\\_=1"
>> Segmentation fault (core dumped)
>> mfabian at magellan:~$
>>
>> occurs with fontconfig 2.4 CVS branch checked out on December 6th 2005.

Still happens with fontconfig 2.3.93.20060103 (2.4 CVS branch checked
out yesterday).

Dirk Müller and me both made a patch to fix the problem.  Dirk already
posted his patch to the fontconfig mailing list a while ago, but this
mail never arrived. Therefore I attach both my and Dirk's patch here
again.

I am not sure which patch is better, both fix the crash but the
behaviour is different.

With Dirk's patch:

    mfabian at magellan:~$ fc-match "Luxi Mono:\\_\\_DUMMY\\_\\_=1"
    hgjgbbmp.ttc: "HGPGothicB" "Regular"
    mfabian at magellan:~$ fc-match "Luxi Mono"
    luximr.ttf: "Luxi Mono" "Regular"
    mfabian at magellan:~$ fc-match sans
    hgjgbbmp.ttc: "HGPGothicB" "Regular"
    mfabian at magellan:~$

I.e. with Dirk's patch the complete pattern is ignored when it
contains __DUMMY__ and a new empty pattern is created which gives the
same result as when trying to match "sans".

With my patch:

    mfabian at magellan:~$ fc-match "Luxi Mono:\\_\\_DUMMY\\_\\_=1"
    luximr.ttf: "Luxi Mono" "Regular"
    mfabian at magellan:~$ fc-match "Luxi Mono"
    luximr.ttf: "Luxi Mono" "Regular"
    mfabian at magellan:~$ fc-match sans
    hgjgbbmp.ttc: "HGPGothicB" "Regular"
    mfabian at magellan:~$

only __DUMMY__ is ignored, the rest of the pattern is used.
I.e. with my patch it behaves the same way as if I add
other junk into the pattern like:

    mfabian at magellan:~$ fc-match "Luxi Mono:nonsense=1"
    luximr.ttf: "Luxi Mono" "Regular"
    mfabian at magellan:~$

Here "nonsense=1" is ignored as well.

I still don't know for what purpose this __DUMMY__ in fcname.c line 33
has been introduced.

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-- 
Mike FABIAN   <mfabian at suse.de>   http://www.suse.de/~mfabian
睡眠不足はいい仕事の敵だ。