packfile: generalize pack directory list

In anticipation of sharing the pack directory listing with the
multi-pack-index, generalize prepare_packed_git_one() into
for_each_file_in_pack_dir().

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

packfile.c

@@ -738,13 +738,14 @@ static void report_pack_garbage(struct string_list *list)
 	report_helper(list, seen_bits, first, list->nr);
 }
 
-static void prepare_packed_git_one(struct repository *r, char *objdir, int local)
+void for_each_file_in_pack_dir(const char *objdir,
+			       each_file_in_pack_dir_fn fn,
+			       void *data)
 {
 	struct strbuf path = STRBUF_INIT;
 	size_t dirnamelen;
 	DIR *dir;
 	struct dirent *de;
-	struct string_list garbage = STRING_LIST_INIT_DUP;
 
 	strbuf_addstr(&path, objdir);
 	strbuf_addstr(&path, "/pack");
@@ -759,51 +760,75 @@ static void prepare_packed_git_one(struct repository *r, char *objdir, int local
 	strbuf_addch(&path, '/');
 	dirnamelen = path.len;
 	while ((de = readdir(dir)) != NULL) {
-		struct packed_git *p;
-		size_t base_len;
-
 		if (is_dot_or_dotdot(de->d_name))
 			continue;
 
 		strbuf_setlen(&path, dirnamelen);
 		strbuf_addstr(&path, de->d_name);
 
-		base_len = path.len;
-		if (strip_suffix_mem(path.buf, &base_len, ".idx")) {
-			/* Don't reopen a pack we already have. */
-			for (p = r->objects->packed_git; p;
-			     p = p->next) {
-				size_t len;
-				if (strip_suffix(p->pack_name, ".pack", &len) &&
-				    len == base_len &&
-				    !memcmp(p->pack_name, path.buf, len))
-					break;
-			}
-			if (p == NULL &&
-			    /*
-			     * See if it really is a valid .idx file with
-			     * corresponding .pack file that we can map.
-			     */
-			    (p = add_packed_git(path.buf, path.len, local)) != NULL)
-				install_packed_git(r, p);
+		fn(path.buf, path.len, de->d_name, data);
+	}
+
+	closedir(dir);
+	strbuf_release(&path);
+}
+
+struct prepare_pack_data {
+	struct repository *r;
+	struct string_list *garbage;
+	int local;
+};
+
+static void prepare_pack(const char *full_name, size_t full_name_len,
+			 const char *file_name, void *_data)
+{
+	struct prepare_pack_data *data = (struct prepare_pack_data *)_data;
+	struct packed_git *p;
+	size_t base_len = full_name_len;
+
+	if (strip_suffix_mem(full_name, &base_len, ".idx")) {
+		/* Don't reopen a pack we already have. */
+		for (p = data->r->objects->packed_git; p; p = p->next) {
+			size_t len;
+			if (strip_suffix(p->pack_name, ".pack", &len) &&
+			    len == base_len &&
+			    !memcmp(p->pack_name, full_name, len))
+				break;
 		}
 
-		if (!report_garbage)
-			continue;
-
-		if (ends_with(de->d_name, ".idx") ||
-		    ends_with(de->d_name, ".pack") ||
-		    ends_with(de->d_name, ".bitmap") ||
-		    ends_with(de->d_name, ".keep") ||
-		    ends_with(de->d_name, ".promisor"))
-			string_list_append(&garbage, path.buf);
-		else
-			report_garbage(PACKDIR_FILE_GARBAGE, path.buf);
+		if (!p) {
+			p = add_packed_git(full_name, full_name_len, data->local);
+			if (p)
+				install_packed_git(data->r, p);
+		}
 	}
-	closedir(dir);
-	report_pack_garbage(&garbage);
-	string_list_clear(&garbage, 0);
-	strbuf_release(&path);
+
+	if (!report_garbage)
+		return;
+
+	if (ends_with(file_name, ".idx") ||
+	    ends_with(file_name, ".pack") ||
+	    ends_with(file_name, ".bitmap") ||
+	    ends_with(file_name, ".keep") ||
+	    ends_with(file_name, ".promisor"))
+		string_list_append(data->garbage, full_name);
+	else
+		report_garbage(PACKDIR_FILE_GARBAGE, full_name);
+}
+
+static void prepare_packed_git_one(struct repository *r, char *objdir, int local)
+{
+	struct prepare_pack_data data;
+	struct string_list garbage = STRING_LIST_INIT_DUP;
+
+	data.r = r;
+	data.garbage = &garbage;
+	data.local = local;
+
+	for_each_file_in_pack_dir(objdir, prepare_pack, &data);
+
+	report_pack_garbage(data.garbage);
+	string_list_clear(data.garbage, 0);
 }
 
 static void prepare_packed_git(struct repository *r);

packfile.h

@@ -28,6 +28,12 @@ extern char *sha1_pack_index_name(const unsigned char *sha1);
 
 extern struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path);
 
+typedef void each_file_in_pack_dir_fn(const char *full_path, size_t full_path_len,
+				      const char *file_pach, void *data);
+void for_each_file_in_pack_dir(const char *objdir,
+			       each_file_in_pack_dir_fn fn,
+			       void *data);
+
 /* A hook to report invalid files in pack directory */
 #define PACKDIR_FILE_PACK 1
 #define PACKDIR_FILE_IDX 2