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From: Junio C Hamano <gitster@pobox.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Kjetil Barvik <barvik@broadpark.no>, git@vger.kernel.org
Subject: Re: [PATCH/RFC v2 2/4] Use 'lstat_cache()' instead of 'has_symlink_leading_path()'
Date: Tue, 06 Jan 2009 15:25:47 -0800	[thread overview]
Message-ID: <7vocykf24k.fsf@gitster.siamese.dyndns.org> (raw)
In-Reply-To: <alpine.LFD.2.00.0901061304280.3057@localhost.localdomain> (Linus Torvalds's message of "Tue, 6 Jan 2009 13:08:58 -0800 (PST)")

Linus Torvalds <torvalds@linux-foundation.org> writes:

>> ...  The previously used call:
>> 
>>    has_symlink_leading_path(len, name);
>> 
>> should be identically with the following call to lstat_cache():
>> 
>>    lstat_cache(len, name,
>>                LSTAT_SYMLINK|LSTAT_DIR,
>>                LSTAT_SYMLINK);
>
> I think the new interface looks worse.
>
> Why don't you just do a new inline function that says
>
> 	static inline int has_symlink_leading_path(int len, const char *name)
> 	{
> 		return lstat_cache(len, name,
> 			LSTAT_SYMLINK|LSTAT_DIR,
> 			LSTAT_SYMLINK);
> 	}
>
> and now you don't need this big patch, and people who don't care about 
> those magic flags don't need to have them. End result: more readable code.

Excellent.

Not that I did not think a backward compatible macro is much easier to
read; after all, ce/ie you mention is a refactorizaton I did myself.

What I didn't think of was that posing the above question is a much better
way to extract a clear explanation why some of these lstat_cache() calls
have LSTAT_NOENT and some of them don't from the author.  It is much
better way than my earlier attempt to do so.

> This is how git has done pretty much all "generalized" versions. See the 
> whole ce_modified() vs ie_modified() thing: they're the same function, 
> it's just that 'ce_modified()' is the traditional simpler interface that 
> works on the default index, while ie_modified() is the "full" version that 
> takes all the details that most uses don't even want to know about.

Yup, thanks for a praise ;-)

  reply	other threads:[~2009-01-06 23:27 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-01-06 20:36 [PATCH/RFC v2 0/4] git checkout: optimise away lots of lstat() calls Kjetil Barvik
2009-01-06 20:36 ` [PATCH/RFC v2 1/4] Optimised, faster, more effective symlink/directory detection Kjetil Barvik
2009-01-06 20:36 ` [PATCH/RFC v2 2/4] Use 'lstat_cache()' instead of 'has_symlink_leading_path()' Kjetil Barvik
2009-01-06 21:08   ` Linus Torvalds
2009-01-06 23:25     ` Junio C Hamano [this message]
2009-01-06 20:36 ` [PATCH/RFC v2 3/4] create_directories() inside entry.c: only check each directory once! Kjetil Barvik
2009-01-06 20:36 ` [PATCH/RFC v2 4/4] remove the old 'has_symlink_leading_path()' function Kjetil Barvik

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