[PATCH v4 1/4] worktree: introduce is_shared_symref()

["Rubén Justo" <rjusto@gmail.com>]

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>
---
 worktree.c | 62 +++++++++++++++++++++++++++---------------------------
 worktree.h |  6 ++++++
 2 files changed, 37 insertions(+), 31 deletions(-)

diff --git a/worktree.c b/worktree.c
index aa43c64119..40cb9874b7 100644
--- a/worktree.c
+++ b/worktree.c
@@ -403,44 +403,44 @@ int is_worktree_being_bisected(const struct worktree *wt,
  * bisect). New commands that do similar things should update this
  * function as well.
  */
-const struct worktree *find_shared_symref(struct worktree **worktrees,
-					  const char *symref,
-					  const char *target)
+int is_shared_symref(const struct worktree *wt, const char *symref,
+		     const char *target)
 {
-	const struct worktree *existing = NULL;
-	int i = 0;
+	const char *symref_target;
+	struct ref_store *refs;
+	int flags;
 
-	for (i = 0; worktrees[i]; i++) {
-		struct worktree *wt = worktrees[i];
-		const char *symref_target;
-		struct ref_store *refs;
-		int flags;
+	if (wt->is_bare)
+		return 0;
 
-		if (wt->is_bare)
-			continue;
+	if (wt->is_detached && !strcmp(symref, "HEAD")) {
+		if (is_worktree_being_rebased(wt, target))
+			return 1;
+		if (is_worktree_being_bisected(wt, target))
+			return 1;
+	}
 
-		if (wt->is_detached && !strcmp(symref, "HEAD")) {
-			if (is_worktree_being_rebased(wt, target)) {
-				existing = wt;
-				break;
-			}
-			if (is_worktree_being_bisected(wt, target)) {
-				existing = wt;
-				break;
-			}
-		}
+	refs = get_worktree_ref_store(wt);
+	symref_target = refs_resolve_ref_unsafe(refs, symref, 0,
+						NULL, &flags);
+	if ((flags & REF_ISSYMREF) &&
+	    symref_target && !strcmp(symref_target, target))
+		return 1;
 
-		refs = get_worktree_ref_store(wt);
-		symref_target = refs_resolve_ref_unsafe(refs, symref, 0,
-							NULL, &flags);
-		if ((flags & REF_ISSYMREF) &&
-		    symref_target && !strcmp(symref_target, target)) {
-			existing = wt;
-			break;
-		}
+	return 0;
+}
+
+const struct worktree *find_shared_symref(struct worktree **worktrees,
+					  const char *symref,
+					  const char *target)
+{
+
+	for (int i = 0; worktrees[i]; i++) {
+		if (is_shared_symref(worktrees[i], symref, target))
+			return worktrees[i];
 	}
 
-	return existing;
+	return NULL;
 }
 
 int submodule_uses_worktrees(const char *path)
diff --git a/worktree.h b/worktree.h
index 9dcea6fc8c..7889c4761d 100644
--- a/worktree.h
+++ b/worktree.h
@@ -149,6 +149,12 @@ const struct worktree *find_shared_symref(struct worktree **worktrees,
 					  const char *symref,
 					  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().
-- 
2.39.2