[Gnu-arch-users] Re: [PATCH] arch speedups on big trees

[Miles Bader]

On Thu, Jan 08, 2004 at 07:45:55AM -0500, Chris Mason wrote:
> Because of arch_binary_files_differ(), diff is only going to get run
> when the files are really different.  Using a pipe probably won't work,
> since we'd need some way to deal with the case where diff is blocking
> because the pipe is full.

The tla process should simply read the pipe (before waiting for the diff
process) -- as soon as any output comes from it, open the output file, and
start copying the pipe output to it; when the pipe gets an EOF, _then_ wait
for the diff process.

As a side benefit, typical `weird' diff output, like `Binary files differ' is
almost certainly smaller than the copy buffer tla would use, so you could
probably avoid writing (and subsequently reading) any files at all in that
case too.

-Miles
-- 
"Whatever you do will be insignificant, but it is very important that
 you do it."  Mahatma Ghandi