[PATCH v2 4/8] worktree: expose function to retrieve worktree names

[Patrick Steinhardt <ps@xxxxxx>]

Introduce a function that retrieves worktree names as present in
".git/worktrees". This function will be used in a subsequent commit.

Signed-off-by: Patrick Steinhardt <ps@xxxxxx>
---
 builtin/worktree.c | 25 ++++++++++++-------------
 worktree.c         | 30 ++++++++++++++++++++++++++++++
 worktree.h         |  8 ++++++++
 3 files changed, 50 insertions(+), 13 deletions(-)

diff --git a/builtin/worktree.c b/builtin/worktree.c
index 87ccd47794c..9b00dbf1265 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -211,27 +211,24 @@ static void prune_dups(struct string_list *l)
 
 static void prune_worktrees(void)
 {
-	struct strbuf reason = STRBUF_INIT;
 	struct strbuf main_path = STRBUF_INIT;
 	struct string_list kept = STRING_LIST_INIT_DUP;
-	char *path;
-	DIR *dir;
-	struct dirent *d;
+	struct strvec worktrees = STRVEC_INIT;
+	struct strbuf reason = STRBUF_INIT;
 
-	path = repo_git_path(the_repository, "worktrees");
-	dir = opendir(path);
-	free(path);
-	if (!dir)
+	if (get_worktree_names(the_repository, &worktrees) < 0 ||
+	    !worktrees.nr)
 		return;
-	while ((d = readdir_skip_dot_and_dotdot(dir)) != NULL) {
+
+	for (size_t i = 0; i < worktrees.nr; i++) {
 		char *path;
+
 		strbuf_reset(&reason);
-		if (should_prune_worktree(d->d_name, &reason, &path, expire))
-			prune_worktree(d->d_name, reason.buf);
+		if (should_prune_worktree(worktrees.v[i], &reason, &path, expire))
+			prune_worktree(worktrees.v[i], reason.buf);
 		else if (path)
-			string_list_append_nodup(&kept, path)->util = xstrdup(d->d_name);
+			string_list_append_nodup(&kept, path)->util = xstrdup(worktrees.v[i]);
 	}
-	closedir(dir);
 
 	strbuf_add_absolute_path(&main_path, repo_get_common_dir(the_repository));
 	/* massage main worktree absolute path to match 'gitdir' content */
@@ -242,6 +239,8 @@ static void prune_worktrees(void)
 
 	if (!show_only)
 		delete_worktrees_dir_if_empty();
+
+	strvec_clear(&worktrees);
 	strbuf_release(&reason);
 }
 
diff --git a/worktree.c b/worktree.c
index c34b9eb74e5..947b7a82209 100644
--- a/worktree.c
+++ b/worktree.c
@@ -988,6 +988,36 @@ int should_prune_worktree(const char *id, struct strbuf *reason, char **wtpath,
 	return rc;
 }
 
+int get_worktree_names(struct repository *repo, struct strvec *out)
+{
+	char *worktrees_dir;
+	struct dirent *d;
+	DIR *dir;
+	int ret;
+
+	worktrees_dir = repo_git_path(repo, "worktrees");
+	dir = opendir(worktrees_dir);
+	if (!dir) {
+		if (errno == ENOENT) {
+			ret = 0;
+			goto out;
+		}
+
+		ret = -1;
+		goto out;
+	}
+
+	while ((d = readdir_skip_dot_and_dotdot(dir)) != NULL)
+		strvec_push(out, d->d_name);
+
+	ret = 0;
+out:
+	if (dir)
+		closedir(dir);
+	free(worktrees_dir);
+	return ret;
+}
+
 static int move_config_setting(const char *key, const char *value,
 			       const char *from_file, const char *to_file)
 {
diff --git a/worktree.h b/worktree.h
index e4bcccdc0ae..59825c37881 100644
--- a/worktree.h
+++ b/worktree.h
@@ -38,6 +38,14 @@ struct worktree **get_worktrees(void);
  */
 struct worktree **get_worktrees_without_reading_head(void);
 
+/*
+ * Retrieve all worktree names. Not all names may correspond to a fully
+ * functional worktree. Returns 0 on success, a negative error code on failure.
+ * Calling the function on a repository that doesn't have any worktrees is not
+ * considered an error.
+ */
+int get_worktree_names(struct repository *repo, struct strvec *out);
+
 /*
  * Returns 1 if linked worktrees exist, 0 otherwise.
  */

-- 
2.49.0.987.g0cc8ee98dc.dirty