[PATCH] GSoC2014 microprojects Rewrite bulk-checkin.c:finish_bulk_checkin() to use a strbuf for handling packname

[Sun He <sunheehnus@gmail.com>]

Signed-off-by: Sun He <sunheehnus@gmail.com>
---
 bulk-checkin.c |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)

diff --git a/bulk-checkin.c b/bulk-checkin.c
index 118c625..e3c7fb2 100644
--- a/bulk-checkin.c
+++ b/bulk-checkin.c
@@ -23,7 +23,8 @@ static struct bulk_checkin_state {
 static void finish_bulk_checkin(struct bulk_checkin_state *state)
 {
 	unsigned char sha1[20];
-	char packname[PATH_MAX];
+    char *packname;
+    struct strbuf sb;
 	int i;
 
 	if (!state->f)
@@ -43,6 +44,10 @@ static void finish_bulk_checkin(struct bulk_checkin_state *state)
 		close(fd);
 	}
 
+     /* 64-1 is more than the sum of len(sha1_to_hex(sha1)) and len(".pack") */
+    strbuf_init(&sb,strlen(get_object_directory())+64);
+    packname = sb.buf;
+
 	sprintf(packname, "%s/pack/pack-", get_object_directory());
 	finish_tmp_packfile(packname, state->pack_tmp_name,
 			    state->written, state->nr_written,
@@ -54,6 +59,9 @@ clear_exit:
 	free(state->written);
 	memset(state, 0, sizeof(*state));
 
+    /* release sb space */
+    strbuf_release(&sb);
+
 	/* Make objects we just wrote available to ourselves */
 	reprepare_packed_git();
 }
-- 
1.7.1

> Rewrite bulk-checkin.c:finish_bulk_checkin() to use a strbuf for handling packname, and explain why this is useful.

char packname[PATH_MAX] (PATH_MAX=4096) in a local function costs too much space, it may cause stack overflow.
Using strbuf to deal with packname is more space-friendly.
I only use the API strbuf_init to alloc enough space for packname. I didn't use other APIs because I want to make the change as little as possible that I don't have to fix other functions which may import new bugs.
Because the space spared for sb is on heap, we must release it after it is not useful.

> Also check if the first argument of pack-write.c:finish_tmp_packfile() can be made const.

Tht first argument of pack-write.c:finish_tmp_packfile() can be made const because we didn't use *name_buffer to change anything.

Cheers,
He Sun

PS: 
Why I cannot sent email to git@vger.kernel.org via my Firefox?
Can you receive my former emails?
Thanks.