commit 160bbe2e336908947c078a78e3ae58100a38e9fc
from: Stefan Sperling <stsp@stsp.name>
date: Wed Mar 18 16:13:46 2020 UTC

jump right to the index of the first delta

commit - e6c1173dcf57c322cbb74af339c615c983c190f3
commit + 160bbe2e336908947c078a78e3ae58100a38e9fc
blob - 058e5043c887bbd0abf19e56bf3c6d7dfe952f16
blob + b4e4dc21f9308f616d81790239027df7bcacdb7b
--- libexec/got-index-pack/got-index-pack.c
+++ libexec/got-index-pack/got-index-pack.c
@@ -560,7 +560,7 @@ index_pack(struct got_pack *pack, int idxfd, FILE *tmp
 	SHA1_CTX ctx;
 	uint8_t packidx_hash[SHA1_DIGEST_LENGTH];
 	ssize_t r, w;
-	int pass, have_ref_deltas = 0;
+	int pass, have_ref_deltas = 0, first_delta_idx = -1;
 	size_t mapoff = 0;
 
 	/* Check pack file header. */
@@ -688,11 +688,18 @@ index_pack(struct got_pack *pack, int idxfd, FILE *tmp
 		    obj->type == GOT_OBJ_TYPE_TAG) {
 			obj->valid = 1;
 			nloose++;
-		} else if (obj->type == GOT_OBJ_TYPE_REF_DELTA)
-			have_ref_deltas = 1;
+		} else {
+			if (first_delta_idx == -1)
+				first_delta_idx = i;
+			if (obj->type == GOT_OBJ_TYPE_REF_DELTA)
+				have_ref_deltas = 1;
+		}
 	}
 	nvalid = nloose;
 
+	if (first_delta_idx == -1)
+		first_delta_idx = 0;
+
 	/* In order to resolve ref deltas we need an in-progress pack index. */
 	if (have_ref_deltas)
 		make_packidx(&packidx, nobj, objects);
@@ -713,7 +720,7 @@ index_pack(struct got_pack *pack, int idxfd, FILE *tmp
 		 * Offset deltas can always be resolved in one pass
 		 * unless the packfile is corrupt.
 		 */
-		for (i = 0; i < nobj; i++) {
+		for (i = first_delta_idx; i < nobj; i++) {
 			obj = &objects[i];
 			if (obj->type != GOT_OBJ_TYPE_REF_DELTA &&
 			    obj->type != GOT_OBJ_TYPE_OFFSET_DELTA)