* [PATCH] Provide a way to flush git-diff-tree's output
@ 2006-05-18 6:58 Paul Mackerras
2006-05-18 7:24 ` Junio C Hamano
0 siblings, 1 reply; 3+ messages in thread
From: Paul Mackerras @ 2006-05-18 6:58 UTC (permalink / raw
To: Junio C Hamano; +Cc: git
Gitk wants to use git-diff-tree as a filter to tell it which ids from
a given list affect a set of files or directories. We don't want to
fork and exec a new git-diff-tree process for each batch of ids, since
there could be a lot of relatively small batches. For example, a
batch could contain as many ids as fit in gitk's headline display
window, i.e. 20 or so, and we would be processing a new batch every
time the user scrolls that window.
The --stdin flag to git-diff-tree is suitable for this, but the main
difficulty is that the output of git-diff-tree gets buffered and
doesn't get sent until the buffer is full.
This provides a way to get git-diff-tree to flush its output buffers.
If a blank line is supplied on git-diff-tree's standard input, it will
flush its output buffers and then accept further input.
Signed-off-by: Paul Mackerras <paulus@samba.org>
---
diff --git a/diff-tree.c b/diff-tree.c
index 7207867..69bb74b 100644
--- a/diff-tree.c
+++ b/diff-tree.c
@@ -138,7 +138,10 @@ int main(int argc, const char **argv)
opt->diffopt.setup |= (DIFF_SETUP_USE_SIZE_CACHE |
DIFF_SETUP_USE_CACHE);
while (fgets(line, sizeof(line), stdin))
- diff_tree_stdin(line);
+ if (line[0] == '\n')
+ fflush(stdout);
+ else
+ diff_tree_stdin(line);
return 0;
}
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] Provide a way to flush git-diff-tree's output
2006-05-18 6:58 [PATCH] Provide a way to flush git-diff-tree's output Paul Mackerras
@ 2006-05-18 7:24 ` Junio C Hamano
2006-05-18 9:43 ` Paul Mackerras
0 siblings, 1 reply; 3+ messages in thread
From: Junio C Hamano @ 2006-05-18 7:24 UTC (permalink / raw
To: Paul Mackerras; +Cc: git
Paul Mackerras <paulus@samba.org> writes:
> The --stdin flag to git-diff-tree is suitable for this, but the main
> difficulty is that the output of git-diff-tree gets buffered and
> doesn't get sent until the buffer is full.
>
> This provides a way to get git-diff-tree to flush its output buffers.
> If a blank line is supplied on git-diff-tree's standard input, it will
> flush its output buffers and then accept further input.
Sounds low impact and sane.
I suspect the usual caveat on bidirectional pipe deadlock
applies to the caller. Does gitk do that? The current code
seems to feed a pre-generated list with "open | cmd <<"
construct to the command, so perhaps you are planning to change
that?
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] Provide a way to flush git-diff-tree's output
2006-05-18 7:24 ` Junio C Hamano
@ 2006-05-18 9:43 ` Paul Mackerras
0 siblings, 0 replies; 3+ messages in thread
From: Paul Mackerras @ 2006-05-18 9:43 UTC (permalink / raw
To: Junio C Hamano; +Cc: git
Junio C Hamano writes:
> Sounds low impact and sane.
>
> I suspect the usual caveat on bidirectional pipe deadlock
> applies to the caller. Does gitk do that? The current code
Gitk will use non-blocking mode on the pipes to/from the git-diff-tree
process, so there isn't a possibility of deadlock that I can see.
> seems to feed a pre-generated list with "open | cmd <<"
> construct to the command, so perhaps you are planning to change
> that?
That's for the "Find" function. I'm in the process of adding the code
to let users enter a list of paths and have gitk highlight the commits
affecting those paths. That will involve a separate invocation of
git-diff-tree. To make it responsive, I'm only going to ask
git-diff-tree about the commits that are visible on the screen - but I
need git-diff-tree to give me an answer quickly, i.e. in less time
than a human can perceive.
Thanks,
Paul.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2006-05-18 9:43 UTC | newest]
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2006-05-18 6:58 [PATCH] Provide a way to flush git-diff-tree's output Paul Mackerras
2006-05-18 7:24 ` Junio C Hamano
2006-05-18 9:43 ` Paul Mackerras
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