+ if (!wt)
+ return get_git_dir();
+ else if (!wt->id)
+ return get_git_common_dir();
+ else
+ return git_common_path("worktrees/%s", wt->id);
+}
+
+static struct worktree *find_worktree_by_suffix(struct worktree **list,
+ const char *suffix)
+{
+ struct worktree *found = NULL;
+ int nr_found = 0, suffixlen;
+
+ suffixlen = strlen(suffix);
+ if (!suffixlen)
+ return NULL;
+
+ for (; *list && nr_found < 2; list++) {
+ const char *path = (*list)->path;
+ int pathlen = strlen(path);
+ int start = pathlen - suffixlen;
+
+ /* suffix must start at directory boundary */
+ if ((!start || (start > 0 && is_dir_sep(path[start - 1]))) &&
+ !fspathcmp(suffix, path + start)) {
+ found = *list;
+ nr_found++;
+ }
+ }
+ return nr_found == 1 ? found : NULL;
+}
+
+struct worktree *find_worktree(struct worktree **list,
+ const char *prefix,
+ const char *arg)
+{
+ struct worktree *wt;
+ char *path;
+ char *to_free = NULL;
+
+ if ((wt = find_worktree_by_suffix(list, arg)))
+ return wt;
+
+ if (prefix)
+ arg = to_free = prefix_filename(prefix, arg);
+ path = real_pathdup(arg, 1);
+ for (; *list; list++)
+ if (!fspathcmp(path, real_path((*list)->path)))
+ break;
+ free(path);
+ free(to_free);
+ return *list;
+}
+
+int is_main_worktree(const struct worktree *wt)
+{
+ return !wt->id;
+}
+
+const char *is_worktree_locked(struct worktree *wt)
+{
+ assert(!is_main_worktree(wt));
+
+ if (!wt->lock_reason_valid) {
+ struct strbuf path = STRBUF_INIT;
+
+ strbuf_addstr(&path, worktree_git_path(wt, "locked"));
+ if (file_exists(path.buf)) {
+ struct strbuf lock_reason = STRBUF_INIT;
+ if (strbuf_read_file(&lock_reason, path.buf, 0) < 0)
+ die_errno(_("failed to read '%s'"), path.buf);
+ strbuf_trim(&lock_reason);
+ wt->lock_reason = strbuf_detach(&lock_reason, NULL);
+ } else
+ wt->lock_reason = NULL;
+ wt->lock_reason_valid = 1;
+ strbuf_release(&path);
+ }
+
+ return wt->lock_reason;
+}
+
+int is_worktree_being_rebased(const struct worktree *wt,
+ const char *target)
+{
+ struct wt_status_state state;
+ int found_rebase;
+
+ memset(&state, 0, sizeof(state));
+ found_rebase = wt_status_check_rebase(wt, &state) &&
+ ((state.rebase_in_progress ||
+ state.rebase_interactive_in_progress) &&
+ state.branch &&
+ starts_with(target, "refs/heads/") &&
+ !strcmp(state.branch, target + strlen("refs/heads/")));
+ free(state.branch);
+ free(state.onto);
+ return found_rebase;
+}
+
+int is_worktree_being_bisected(const struct worktree *wt,
+ const char *target)
+{
+ struct wt_status_state state;
+ int found_rebase;
+
+ memset(&state, 0, sizeof(state));
+ found_rebase = wt_status_check_bisect(wt, &state) &&
+ state.branch &&
+ starts_with(target, "refs/heads/") &&
+ !strcmp(state.branch, target + strlen("refs/heads/"));
+ free(state.branch);
+ return found_rebase;
+}
+
+/*
+ * note: this function should be able to detect shared symref even if
+ * HEAD is temporarily detached (e.g. in the middle of rebase or
+ * bisect). New commands that do similar things should update this
+ * function as well.
+ */
+const struct worktree *find_shared_symref(const char *symref,
+ const char *target)
+{
+ const struct worktree *existing = NULL;
+ static struct worktree **worktrees;