worktree: introduce is_shared_symref()

Add a new function, is_shared_symref(), which contains the heart of
find_shared_symref().  Refactor find_shared_symref() to use the new
function is_shared_symref().

Soon, we will use is_shared_symref() to search for symref beyond
the first worktree that matches.

Signed-off-by: Rubén Justo <rjusto@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/worktree.h b/worktree.h
index 9dcea6fc8c..7889c4761d 100644
--- a/worktree.h
+++ b/worktree.h
@@ -150,6 +150,12 @@ const struct worktree *find_shared_symref(struct worktree **worktrees,
 					  const char *target);
 
 /*
+ * Returns true if a symref points to a ref in a worktree.
+ */
+int is_shared_symref(const struct worktree *wt,
+		     const char *symref, const char *target);
+
+/*
  * Similar to head_ref() for all HEADs _except_ one from the current
  * worktree, which is covered by head_ref().
  */