bundle: remove "ref_list" in favor of string-list.c API

Move away from the "struct ref_list" in bundle.c in favor of the
almost identical string-list.c API.

That API fits this use-case perfectly, but did not exist in its
current form when this code was added in 2e0afafebd (Add git-bundle:
move objects and references by archive, 2007-02-22), with hindsight we
could have used the path-list API, which later got renamed to
string-list. See 8fd2cb4069 (Extract helper bits from
c-merge-recursive work, 2006-07-25)

We need to change "name" to "string" and "oid" to "util" to make this
conversion, but other than that the APIs are pretty much identical for
what bundle.c made use of.

Let's also replace the memset(..,0,...) pattern with a more idiomatic
"INIT" macro, and finally add a *_release() function so to free the
allocated memory.

Before this the add_to_ref_list() would leak memory, now e.g. "bundle
list-heads" reports no memory leaks at all under valgrind.

In the bundle_header_init() function we're using a clever trick to
memcpy() what we'd get from the corresponding
BUNDLE_HEADER_INIT. There is a concurrent series to make use of that
pattern more generally, see [1].

1. https://lore.kernel.org/git/cover-0.5-00000000000-20210701T104855Z-avarab@gmail.com/

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 28 insertions, 24 deletions

diff --git a/bundle.c b/bundle.c
index 7210e5e710..ab63f40226 100644
--- a/bundle.c
+++ b/bundle.c
@@ -23,13 +23,16 @@ static struct {
 	{ 3, v3_bundle_signature },
 };
 
-static void add_to_ref_list(const struct object_id *oid, const char *name,
-		struct ref_list *list)
+void bundle_header_init(struct bundle_header *header)
 {
-	ALLOC_GROW(list->list, list->nr + 1, list->alloc);
-	oidcpy(&list->list[list->nr].oid, oid);
-	list->list[list->nr].name = xstrdup(name);
-	list->nr++;
+	struct bundle_header blank = BUNDLE_HEADER_INIT;
+	memcpy(header, &blank, sizeof(*header));
+}
+
+void bundle_header_release(struct bundle_header *header)
+{
+	string_list_clear(&header->prerequisites, 1);
+	string_list_clear(&header->references, 1);
 }
 
 static int parse_capability(struct bundle_header *header, const char *capability)
@@ -112,10 +115,11 @@ static int parse_bundle_header(int fd, struct bundle_header *header,
 			status = -1;
 			break;
 		} else {
+			struct object_id *dup = oiddup(&oid);
 			if (is_prereq)
-				add_to_ref_list(&oid, "", &header->prerequisites);
+				string_list_append(&header->prerequisites, "")->util = dup;
 			else
-				add_to_ref_list(&oid, p + 1, &header->references);
+				string_list_append(&header->references, p + 1)->util = dup;
 		}
 	}
 
@@ -139,19 +143,19 @@ int read_bundle_header(const char *path, struct bundle_header *header)
 
 int is_bundle(const char *path, int quiet)
 {
-	struct bundle_header header;
+	struct bundle_header header = BUNDLE_HEADER_INIT;
 	int fd = open(path, O_RDONLY);
 
 	if (fd < 0)
 		return 0;
-	memset(&header, 0, sizeof(header));
 	fd = parse_bundle_header(fd, &header, quiet ? NULL : path);
 	if (fd >= 0)
 		close(fd);
+	bundle_header_release(&header);
 	return (fd >= 0);
 }
 
-static int list_refs(struct ref_list *r, int argc, const char **argv)
+static int list_refs(struct string_list *r, int argc, const char **argv)
 {
 	int i;
 
@@ -162,14 +166,14 @@ static int list_refs(struct ref_list *r, int argc, const char **argv)
 		if (argc > 1) {
 			int j;
 			for (j = 1; j < argc; j++)
-				if (!strcmp(r->list[i].name, argv[j]))
+				if (!strcmp(r->items[i].string, argv[j]))
 					break;
 			if (j == argc)
 				continue;
 		}
 
-		oid = &r->list[i].oid;
-		name = r->list[i].name;
+		oid = r->items[i].util;
+		name = r->items[i].string;
 		printf("%s %s\n", oid_to_hex(oid), name);
 	}
 	return 0;
@@ -186,7 +190,7 @@ int verify_bundle(struct repository *r,
 	 * Do fast check, then if any prereqs are missing then go line by line
 	 * to be verbose about the errors
 	 */
-	struct ref_list *p = &header->prerequisites;
+	struct string_list *p = &header->prerequisites;
 	struct rev_info revs;
 	const char *argv[] = {NULL, "--all", NULL};
 	struct commit *commit;
@@ -198,9 +202,9 @@ int verify_bundle(struct repository *r,
 
 	repo_init_revisions(r, &revs, NULL);
 	for (i = 0; i < p->nr; i++) {
-		struct ref_list_entry *e = p->list + i;
-		const char *name = e->name;
-		struct object_id *oid = &e->oid;
+		struct string_list_item *e = p->items + i;
+		const char *name = e->string;
+		struct object_id *oid = e->util;
 		struct object *o = parse_object(r, oid);
 		if (o) {
 			o->flags |= PREREQ_MARK;
@@ -225,9 +229,9 @@ int verify_bundle(struct repository *r,
 			i--;
 
 	for (i = 0; i < p->nr; i++) {
-		struct ref_list_entry *e = p->list + i;
-		const char *name = e->name;
-		struct object_id *oid = &e->oid;
+		struct string_list_item *e = p->items + i;
+		const char *name = e->string;
+		const struct object_id *oid = e->util;
 		struct object *o = parse_object(r, oid);
 		assert(o); /* otherwise we'd have returned early */
 		if (o->flags & SHOWN)
@@ -239,15 +243,15 @@ int verify_bundle(struct repository *r,
 
 	/* Clean up objects used, as they will be reused. */
 	for (i = 0; i < p->nr; i++) {
-		struct ref_list_entry *e = p->list + i;
-		struct object_id *oid = &e->oid;
+		struct string_list_item *e = p->items + i;
+		struct object_id *oid = e->util;
 		commit = lookup_commit_reference_gently(r, oid, 1);
 		if (commit)
 			clear_commit_marks(commit, ALL_REV_FLAGS);
 	}
 
 	if (verbose) {
-		struct ref_list *r;
+		struct string_list *r;
 
 		r = &header->references;
 		printf_ln(Q_("The bundle contains this ref:",