Re: [PATCH] Do not call git-rev-list from git-fetch-pack

[Junio C Hamano <junkio@cox.net>]

Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:

> Note that the best thing would probably be to add a binary search to that, 
> and *not* stop at the first ack'ed rev, but rather count them, and stop at 
> MAX_HAS.

Another alternative.

We send "haves" in order, without 2^n skipping nor binary search
backtrack.  Instead, add a logic in upload-pack to see if a
newly arrived "have" is a direct child of anything that we have
already heard about, and mark to ignore them.  We need to add
that MAX_HAS counting to fetch-pack side for this to work.

This is not even compile tested, but just to outline the idea.

(... now off to day-job ...)

---

diff --git a/upload-pack.c b/upload-pack.c
index 8a41caf..d98a28e 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -3,9 +3,11 @@
 #include "pkt-line.h"
 #include "tag.h"
 #include "object.h"
+#include "commit.h"
 
 static const char upload_pack_usage[] = "git-upload-pack [--strict] [--timeout=nn] <dir>";
 
+#define THEY_HAVE (1U << 0)
 #define MAX_HAS (16)
 #define MAX_NEEDS (256)
 static int nr_has = 0, nr_needs = 0;
@@ -92,6 +94,20 @@ static int got_sha1(char *hex, unsigned 
 		return 0;
 	nr = nr_has;
 	if (nr < MAX_HAS) {
+		struct object *o = lookup_object(sha1);
+		if (!o || (o->parsed || !parse_object(sha1)))
+			die("oops");
+		if (o->type == commit_type) {
+			struct commit_list *parents;
+			if (o->flags & THEY_HAVE)
+				return 0;
+			o->flags |= THEY_HAVE;
+			for (parents = ((struct commit*)o)->parents;
+			     parents;
+			     parents = parents->next) {
+				parents->item->object.flags |= THEY_HAVE;
+			}
+		}
 		memcpy(has_sha1[nr], sha1, 20);
 		nr_has = nr+1;
 	}
@@ -104,6 +120,9 @@ static int get_common_commits(void)
 	unsigned char sha1[20];
 	int len;
 
+	track_object_refs = 0;
+	save_commit_buffer = 0;
+
 	for(;;) {
 		len = packet_read_line(0, line, sizeof(line));
 		reset_timeout();