Fix packname hash generation.

This changes the generation of hash packfiles have in their names, from
"hash of object names as fed to us" to "hash of object names in the
resulting pack, in the order they appear in the index file".  The new
"git-index-pack" command is taught to output the computed hash value
to its standard output.

With this, we can store downloaded pack in a temporary file without
knowing its final name, run git-index-pack to generate idx for it
while finding out its final name, and then rename the pack and idx to
their final names.

Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 10 insertions, 4 deletions

diff --git a/pack-objects.c b/pack-objects.c
index 3d62278..ef55cab 100644
--- a/pack-objects.c
+++ b/pack-objects.c
@@ -393,6 +393,7 @@ int main(int argc, char **argv)
 	SHA_CTX ctx;
 	char line[PATH_MAX + 20];
 	int window = 10, depth = 10, pack_to_stdout = 0;
+	struct object_entry **list;
 	int i;
 
 	for (i = 1; i < argc; i++) {
@@ -435,7 +436,6 @@ int main(int argc, char **argv)
 	if (pack_to_stdout != !base_name)
 		usage(pack_usage);
 
-	SHA1_Init(&ctx);
 	while (fgets(line, sizeof(line), stdin) != NULL) {
 		unsigned int hash;
 		char *p;
@@ -451,10 +451,8 @@ int main(int argc, char **argv)
 				continue;
 			hash = hash * 11 + c;
 		}
-		if (add_object_entry(sha1, hash))
-			SHA1_Update(&ctx, sha1, 20);
+		add_object_entry(sha1, hash);
 	}
-	SHA1_Final(object_list_sha1, &ctx);
 	if (non_empty && !nr_objects)
 		return 0;
 	get_object_details();
@@ -462,6 +460,14 @@ int main(int argc, char **argv)
 	fprintf(stderr, "Packing %d objects\n", nr_objects);
 
 	sorted_by_sha = create_sorted_list(sha1_sort);
+	SHA1_Init(&ctx);
+	list = sorted_by_sha;
+	for (i = 0; i < nr_objects; i++) {
+		struct object_entry *entry = *list++;
+		SHA1_Update(&ctx, entry->sha1, 20);
+	}
+	SHA1_Final(object_list_sha1, &ctx);
+
 	sorted_by_type = create_sorted_list(type_size_sort);
 	if (window && depth)
 		find_deltas(sorted_by_type, window+1, depth);