refspec: Add func to distinguish negative refspecs

ryan-ph · ryan-ph · commit 111fa3a6a101 · 2024-12-16T23:58:40.000+09:00
Negative refspecs were added in Git v2.29.0 and are denoted by prefixing
a refspec with a caret. This adds a way to distinguish if a refspec is
negative and match negative refspecs.
diff --git a/include/git2/refspec.h b/include/git2/refspec.h
@@ -78,6 +78,15 @@ GIT_EXTERN(int) git_refspec_force(const git_refspec *refspec);
  */
 GIT_EXTERN(git_direction) git_refspec_direction(const git_refspec *spec);
 
+/**
+ * Check if a refspec's source descriptor matches a negative reference
+ *
+ * @param refspec the refspec
+ * @param refname the name of the reference to check
+ * @return 1 if the refspec matches, 0 otherwise
+ */
+GIT_EXTERN(int) git_refspec_src_matches_negative(const git_refspec *refspec, const char *refname);
+
 /**
  * Check if a refspec's source descriptor matches a reference
  *
diff --git a/src/libgit2/refspec.c b/src/libgit2/refspec.c
@@ -225,6 +225,14 @@ int git_refspec_force(const git_refspec *refspec)
 	return refspec->force;
 }
 
+int git_refspec_src_matches_negative(const git_refspec *refspec, const char *refname)
+{
+	if (refspec == NULL || refspec->src == NULL || !git_refspec_is_negative(refspec))
+		return false;
+
+	return (wildmatch(refspec->src + 1, refname, 0) == 0);
+}
+
 int git_refspec_src_matches(const git_refspec *refspec, const char *refname)
 {
 	if (refspec == NULL || refspec->src == NULL)
@@ -340,6 +348,14 @@ int git_refspec_is_wildcard(const git_refspec *spec)
 	return (spec->src[strlen(spec->src) - 1] == '*');
 }
 
+int git_refspec_is_negative(const git_refspec *spec)
+{
+	GIT_ASSERT_ARG(spec);
+	GIT_ASSERT_ARG(spec->src);
+
+	return (spec->src[0] == '^');
+}
+
 git_direction git_refspec_direction(const git_refspec *spec)
 {
 	GIT_ASSERT_ARG(spec);
diff --git a/src/libgit2/refspec.h b/src/libgit2/refspec.h
@@ -45,6 +45,14 @@ int git_refspec__serialize(git_str *out, const git_refspec *refspec);
  */
 int git_refspec_is_wildcard(const git_refspec *spec);
 
+/**
+ * Determines if a refspec is a negative refspec.
+ *
+ * @param spec the refspec
+ * @return 1 if the refspec is a negative, 0 otherwise
+ */
+int git_refspec_is_negative(const git_refspec *spec);
+
 /**
  * DWIM `spec` with `refs` existing on the remote, append the dwim'ed
  * result in `out`.
