bug#9086: ls --color: 30% speed-up and case-insensitive suffixes [Re: bug#9086

[Jim Meyering]

Pádraig Brady wrote:
> On 10/09/2012 01:32 PM, Jim Meyering wrote:
>> Pádraig Brady wrote:
...
>>> So do we now only support suffixes delimited by '.' ?
>>> Previously the delimiter was arbitrary or optional:
>>>
>>>    touch star; LS_COLORS="*tar=01;31" /bin/ls --color *tar
>>
>> Good catch.  I realized that early on, but then forgot to mention it.
>> Yes, I would have to document that the "." is now required.
>> It seems like a reasonable restriction, but technically
>> it could be called a regression.
>>
>> Also, with these changes, a multiple-"." suffix will no longer work.
>> I.e., before, if you wanted to give *.tar.xz files a color different
>> from plain *.xz files, you could.
>>
>> Does anyone object to that?
>
> It's marginal, though I'd be inclined to keep the existing
> support for arbitrary suffixes. We could fall back to the
> slower linear scan iff an entension entry in LS_COLORS didn't
> contain a single '.'  To be more generally performant and
> support a longest suffix match we'd have to use something
> like a trie I think.

Well, I confess that I am not inclined to spend more time on this,
and don't think the dot-less or longest-suffix use cases are worth the
added code (we were already using most of hash.c already, so my change
induced almost no bloat), so I'm tempted to go ahead with the patch and
wait for complaints before adding trie-based lookup.

wdyt?