Re: [PATCH/WIP 02/11] notes-merge: use opendir/readdir instead of using read_directory()

From: Nguyen Thai Ngoc Duy <pclouds@gmail.com>
Date: Oct 28, 2011, 20:47 UTC
Message-ID: <CACsJy8B8Zd092JsBqtuVA-zR-o_uPH2m73wJa0uqgkokE5qnNw@mail.gmail.com>
In-Reply-To: <7vzkgmz6v0.fsf@alter.siamese.dyndns.org>

On Fri, Oct 28, 2011 at 4:23 AM, Junio C Hamano <gitster@pobox.com> wrote:

Show 35 quoted lines

> Nguyen Thai Ngoc Duy <pclouds@gmail.com> writes:
>
>>> When read_directory("where/ever") is called, what kind of paths does it
>>> collect? Do the paths the function collects share "where/ever" as their
>>> common prefix? I thought it collects the paths relative to whatever
>>> top-level directory given to the function, so that "where/ever" could be
>>> anything.
>>
>> Correct. But read_directory() takes pathspec now so naturally it does
>> not treat "where/ever" a common prefix anymore.  So it has to open(".")
>> and starts from there.
>
> That is a puzzling statement. The read_directory() function takes:
>
>  - dir: use this struct to pass traversal status and collected paths;
>
>  - path, len: this is the directory (not a pathspec) we start traversal
>   from; and
>
>  - pathspec: these are the patterns that specify which parts of the
>   directory hierarchy under <path,len> are traversed.
>
> I do not see any good reason for <path,len> to become a match pattern. Are
> you trying to get it prepended to elements in pathspec[] and match the path
> collected including the <path> part?
>
> Why?
>
> I could see that "open . and start from there, treating as if <path,len>
> is also pathspec" could be made to work, but I do not see why that is
> desirable.
>
> In other words, are there existing callers that abuse read_directory()
> to feed a pattern in <path,len>? Maybe they should be the one that needs
> fixing instead?

fill_directory() tries to calculate a common prefix (i.e. <path,len> to read_directory()) from pathspec and that may or may not work when pathspec magic comes into play. But yes, I could just make fill_directory() pass <"",0> to read_directory() and keep <path,len> in read_directory() for notes-merge and future users.

-- 
Duy