worktree: add details to the worktree struct

In addition to the absolute path in the worktree struct, add the location
of the git dir, the head ref (if not detached), the head revision sha1,
whether or not head is detached, and whether or not the worktree is a
bare repo.

Signed-off-by: Michael Rappazzo <rappazzo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

worktree.c

@@ -9,6 +9,8 @@ void free_worktrees(struct worktree **worktrees)
 
 	for (i = 0; worktrees[i]; i++) {
 		free(worktrees[i]->path);
+		free(worktrees[i]->git_dir);
+		free(worktrees[i]->head_ref);
 		free(worktrees[i]);
 	}
 	free (worktrees);
@@ -49,6 +51,21 @@ static int parse_ref(char *path_to_ref, struct strbuf *ref, int *is_detached)
 	return 0;
 }
 
+/**
+ * Add the head_sha1 and head_ref (if not detached) to the given worktree
+ */
+static void add_head_info(struct strbuf *head_ref, struct worktree *worktree)
+{
+	if (head_ref->len) {
+		if (worktree->is_detached) {
+			get_sha1_hex(head_ref->buf, worktree->head_sha1);
+		} else {
+			resolve_ref_unsafe(head_ref->buf, 0, worktree->head_sha1, NULL);
+			worktree->head_ref = strbuf_detach(head_ref, NULL);
+		}
+	}
+}
+
 /**
  * get the main worktree
  */
@@ -59,19 +76,29 @@ static struct worktree *get_main_worktree(void)
 	struct strbuf worktree_path = STRBUF_INIT;
 	struct strbuf gitdir = STRBUF_INIT;
 	struct strbuf head_ref = STRBUF_INIT;
+	int is_bare = 0;
+	int is_detached = 0;
 
 	strbuf_addf(&gitdir, "%s", absolute_path(get_git_common_dir()));
 	strbuf_addbuf(&worktree_path, &gitdir);
-	if (!strbuf_strip_suffix(&worktree_path, "/.git"))
+	is_bare = !strbuf_strip_suffix(&worktree_path, "/.git");
+	if (is_bare)
 		strbuf_strip_suffix(&worktree_path, "/.");
 
 	strbuf_addf(&path, "%s/HEAD", get_git_common_dir());
 
-	if (parse_ref(path.buf, &head_ref, NULL) >= 0) {
-		worktree = xmalloc(sizeof(struct worktree));
-		worktree->path = strbuf_detach(&worktree_path, NULL);
-		worktree->git_dir = strbuf_detach(&gitdir, NULL);
-	}
+	if (parse_ref(path.buf, &head_ref, &is_detached) < 0)
+		goto done;
+
+	worktree = xmalloc(sizeof(struct worktree));
+	worktree->path = strbuf_detach(&worktree_path, NULL);
+	worktree->git_dir = strbuf_detach(&gitdir, NULL);
+	worktree->is_bare = is_bare;
+	worktree->head_ref = NULL;
+	worktree->is_detached = is_detached;
+	add_head_info(&head_ref, worktree);
+
+done:
 	strbuf_release(&path);
 	strbuf_release(&gitdir);
 	strbuf_release(&worktree_path);
@@ -86,6 +113,7 @@ static struct worktree *get_linked_worktree(const char *id)
 	struct strbuf worktree_path = STRBUF_INIT;
 	struct strbuf gitdir = STRBUF_INIT;
 	struct strbuf head_ref = STRBUF_INIT;
+	int is_detached = 0;
 
 	if (!id)
 		die("Missing linked worktree name");
@@ -107,11 +135,16 @@ static struct worktree *get_linked_worktree(const char *id)
 	strbuf_reset(&path);
 	strbuf_addf(&path, "%s/worktrees/%s/HEAD", get_git_common_dir(), id);
 
-	if (parse_ref(path.buf, &head_ref, NULL) >= 0) {
-		worktree = xmalloc(sizeof(struct worktree));
-		worktree->path = strbuf_detach(&worktree_path, NULL);
-		worktree->git_dir = strbuf_detach(&gitdir, NULL);
-	}
+	if (parse_ref(path.buf, &head_ref, &is_detached) < 0)
+		goto done;
+
+	worktree = xmalloc(sizeof(struct worktree));
+	worktree->path = strbuf_detach(&worktree_path, NULL);
+	worktree->git_dir = strbuf_detach(&gitdir, NULL);
+	worktree->is_bare = 0;
+	worktree->head_ref = NULL;
+	worktree->is_detached = is_detached;
+	add_head_info(&head_ref, worktree);
 
 done:
 	strbuf_release(&path);

worktree.h

@@ -4,6 +4,10 @@
 struct worktree {
 	char *path;
 	char *git_dir;
+	char *head_ref;
+	unsigned char head_sha1[20];
+	int is_detached;
+	int is_bare;
 };
 
 /* Functions for acting on the information about worktrees. */