refs: introduce git_reference_name_is_valid

Provide a function that can check reference name validity but can also
signal when an error occurs.  Use the name "name_is_valid", which is
more suggestive of checking a given name, rather than "is_valid_name",
which suggests that the function checks the validity of the current
reference's name.

1 files changed, 17 insertions, 0 deletions

diff --git a/include/git2/refs.h b/include/git2/refs.h
index c9cce2212..6145811bb 100644
--- a/include/git2/refs.h
+++ b/include/git2/refs.h
@@ -743,6 +743,23 @@ GIT_EXTERN(int) git_reference_peel(
  *    the characters '~', '^', ':', '\\', '?', '[', and '*', and the
  *    sequences ".." and "@{" which have special meaning to revparse.
  *
+ * @param valid output pointer to set with validity of given reference name
+ * @param refname name to be checked.
+ * @return 0 on success or an error code
+ */
+GIT_EXTERN(int) git_reference_name_is_valid(int *valid, const char *refname);
+
+/**
+ * Ensure the reference name is well-formed.
+ *
+ * Valid reference names must follow one of two patterns:
+ *
+ * 1. Top-level names must contain only capital letters and underscores,
+ *    and must begin and end with a letter. (e.g. "HEAD", "ORIG_HEAD").
+ * 2. Names prefixed with "refs/" can be almost anything.  You must avoid
+ *    the characters '~', '^', ':', '\\', '?', '[', and '*', and the
+ *    sequences ".." and "@{" which have special meaning to revparse.
+ *
  * @param refname name to be checked.
  * @return 1 if the reference name is acceptable; 0 if it isn't
  */