Re: [PATCH] packfile: use extra variable to clarify code in use_pack()

[Ramsay Jones <ramsay@ramsayjones.plus.com>]

On 13/03/2019 21:49, Ramsay Jones wrote:
> From: Jeff King <peff@peff.net>
> 
> We use the "offset" variable for two purposes. It's the offset into
> the packfile that the caller provides us (which is rightly an off_t,
> since we might have a packfile much larger than memory). But later we
> also use it as the offset within a given mmap'd window, and that
> window cannot be larger than a size_t.
> 
> For the second use, the fact that we have an off_t leads to some
> confusion when we assign it to the "left" variable, which is a size_t.
> It is in fact correct (because our earlier "offset -= win->offset" means
> we must be within the pack window), but using a separate variable of the
> right type makes that much more obvious.
> 
> Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
> ---
> 
> Hi Junio,
> 
> As promised, I am forwarding a 'saved' patch from Jeff, which was
> a by-product of a long-ago discussion regarding commit 5efde212fc
> ("zlib.c: use size_t for size", 2018-10-14).
> 
> I have tested this patch on 'pu' (@6fd68134c8) and directly on top
> of commit 5efde212fc. (see branch 'mk/use-size-t-in-zlib').
> 
> However, whilst I have been waiting for the tests to finish, I have
> been looking at the code and concluded that this does not _have_ to
> be applied on top of commit 5efde212fc. (I haven't done it, but just
> tweak the context line to read 'unsigned long *left)' rather than
> 'size_t *left)' and this should apply cleanly to 'master'. Also, it
> would have _exactly_ the same effect as the current code! ;-) ).

I have now done:

  $ diff 0001-packfile-use-extra-variable-to-clarify-code-in-use_p.patch ttt.patch
  28c28
  <  		size_t *left)
  ---
  >  		unsigned long *left)
  $ 

... this and it applies cleanly to 'master', builds and passes tests.

Just FYI. ;-)

ATB,
Ramsay Jones