indexer: name pack files after trailer hash

Upstream git.git has changed the way how packfiles are named.
Previously, they were using a hash of the contained object's OIDs, which
has then been changed to use the hash of the complete packfile instead.
See 1190a1acf (pack-objects: name pack files after trailer hash,
2013-12-05) in the git.git repository for more information on this
change.

This commit changes our logic to match the behavior of core git.

1 files changed, 4 insertions, 8 deletions

diff --git a/src/indexer.c b/src/indexer.c
index 606de2ef6..0ad7869ef 100644
--- a/src/indexer.c
+++ b/src/indexer.c
@@ -931,7 +931,6 @@ int git_indexer_commit(git_indexer *idx, git_transfer_progress *stats)
 	git_buf filename = GIT_BUF_INIT;
 	struct entry *entry;
 	git_oid trailer_hash, file_hash;
-	git_hash_ctx ctx;
 	git_filebuf index_file = {0};
 	void *packfile_trailer;
 
@@ -940,9 +939,6 @@ int git_indexer_commit(git_indexer *idx, git_transfer_progress *stats)
 		return -1;
 	}
 
-	if (git_hash_ctx_init(&ctx) < 0)
-		return -1;
-
 	/* Test for this before resolve_deltas(), as it plays with idx->off */
 	if (idx->off + 20 < idx->pack->mwf.size) {
 		giterr_set(GITERR_INDEXER, "unexpected data at the end of the pack");
@@ -986,6 +982,10 @@ int git_indexer_commit(git_indexer *idx, git_transfer_progress *stats)
 
 	git_vector_sort(&idx->objects);
 
+	/* Use the trailer hash as the pack file name to ensure
+	 * files with different contents have different names */
+	git_oid_cpy(&idx->hash, &trailer_hash);
+
 	git_buf_sets(&filename, idx->pack->pack_name);
 	git_buf_shorten(&filename, strlen("pack"));
 	git_buf_puts(&filename, "idx");
@@ -1010,9 +1010,7 @@ int git_indexer_commit(git_indexer *idx, git_transfer_progress *stats)
 	/* Write out the object names (SHA-1 hashes) */
 	git_vector_foreach(&idx->objects, i, entry) {
 		git_filebuf_write(&index_file, &entry->oid, sizeof(git_oid));
-		git_hash_update(&ctx, &entry->oid, GIT_OID_RAWSZ);
 	}
-	git_hash_final(&idx->hash, &ctx);
 
 	/* Write out the CRC32 values */
 	git_vector_foreach(&idx->objects, i, entry) {
@@ -1086,14 +1084,12 @@ int git_indexer_commit(git_indexer *idx, git_transfer_progress *stats)
 	idx->pack_committed = 1;
 
 	git_buf_free(&filename);
-	git_hash_ctx_cleanup(&ctx);
 	return 0;
 
 on_error:
 	git_mwindow_free_all(&idx->pack->mwf);
 	git_filebuf_cleanup(&index_file);
 	git_buf_free(&filename);
-	git_hash_ctx_cleanup(&ctx);
 	return -1;
 }