refs: move ref name helpers around

strbuf_branchname(), strbuf_check_{branch,tag}_ref() are helper
functions to deal with branch and tag names, and the fact that they
happen to use strbuf to hold the name of a branch or a tag is not
essential.  These functions fit better in the refs API than strbuf
API, the latter of which is about string manipulations.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/tag.c

@@ -447,17 +447,6 @@ static int parse_msg_arg(const struct option *opt, const char *arg, int unset)
 	return 0;
 }
 
-static int strbuf_check_tag_ref(struct strbuf *sb, const char *name)
-{
-	if (name[0] == '-')
-		return -1;
-
-	strbuf_reset(sb);
-	strbuf_addf(sb, "refs/tags/%s", name);
-
-	return check_refname_format(sb->buf, 0);
-}
-
 int cmd_tag(int argc,
 	    const char **argv,
 	    const char *prefix,

object-name.c

@@ -1734,42 +1734,6 @@ int repo_interpret_branch_name(struct repository *r,
 	return -1;
 }
 
-void strbuf_branchname(struct strbuf *sb, const char *name, unsigned allowed)
-{
-	int len = strlen(name);
-	struct interpret_branch_name_options options = {
-		.allowed = allowed
-	};
-	int used = repo_interpret_branch_name(the_repository, name, len, sb,
-					      &options);
-
-	if (used < 0)
-		used = 0;
-	strbuf_add(sb, name + used, len - used);
-}
-
-int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
-{
-	if (startup_info->have_repository)
-		strbuf_branchname(sb, name, INTERPRET_BRANCH_LOCAL);
-	else
-		strbuf_addstr(sb, name);
-
-	/*
-	 * This splice must be done even if we end up rejecting the
-	 * name; builtin/branch.c::copy_or_rename_branch() still wants
-	 * to see what the name expanded to so that "branch -m" can be
-	 * used as a tool to correct earlier mistakes.
-	 */
-	strbuf_splice(sb, 0, 0, "refs/heads/", 11);
-
-	if (*name == '-' ||
-	    !strcmp(sb->buf, "refs/heads/HEAD"))
-		return -1;
-
-	return check_refname_format(sb->buf, 0);
-}
-
 void object_context_release(struct object_context *ctx)
 {
 	free(ctx->path);

refs.c

@@ -697,6 +697,53 @@ static char *substitute_branch_name(struct repository *r,
 	return NULL;
 }
 
+void strbuf_branchname(struct strbuf *sb, const char *name, unsigned allowed)
+{
+	int len = strlen(name);
+	struct interpret_branch_name_options options = {
+		.allowed = allowed
+	};
+	int used = repo_interpret_branch_name(the_repository, name, len, sb,
+					      &options);
+
+	if (used < 0)
+		used = 0;
+	strbuf_add(sb, name + used, len - used);
+}
+
+int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
+{
+	if (startup_info->have_repository)
+		strbuf_branchname(sb, name, INTERPRET_BRANCH_LOCAL);
+	else
+		strbuf_addstr(sb, name);
+
+	/*
+	 * This splice must be done even if we end up rejecting the
+	 * name; builtin/branch.c::copy_or_rename_branch() still wants
+	 * to see what the name expanded to so that "branch -m" can be
+	 * used as a tool to correct earlier mistakes.
+	 */
+	strbuf_splice(sb, 0, 0, "refs/heads/", 11);
+
+	if (*name == '-' ||
+	    !strcmp(sb->buf, "refs/heads/HEAD"))
+		return -1;
+
+	return check_refname_format(sb->buf, 0);
+}
+
+int strbuf_check_tag_ref(struct strbuf *sb, const char *name)
+{
+	if (name[0] == '-')
+		return -1;
+
+	strbuf_reset(sb);
+	strbuf_addf(sb, "refs/tags/%s", name);
+
+	return check_refname_format(sb->buf, 0);
+}
+
 int repo_dwim_ref(struct repository *r, const char *str, int len,
 		  struct object_id *oid, char **ref, int nonfatal_dangling_mark)
 {

refs.h

@@ -180,6 +180,35 @@ int repo_dwim_log(struct repository *r, const char *str, int len, struct object_
  */
 char *repo_default_branch_name(struct repository *r, int quiet);
 
+/*
+ * Copy "name" to "sb", expanding any special @-marks as handled by
+ * repo_interpret_branch_name(). The result is a non-qualified branch name
+ * (so "foo" or "origin/master" instead of "refs/heads/foo" or
+ * "refs/remotes/origin/master").
+ *
+ * Note that the resulting name may not be a syntactically valid refname.
+ *
+ * If "allowed" is non-zero, restrict the set of allowed expansions. See
+ * repo_interpret_branch_name() for details.
+ */
+void strbuf_branchname(struct strbuf *sb, const char *name,
+		       unsigned allowed);
+
+/*
+ * Like strbuf_branchname() above, but confirm that the result is
+ * syntactically valid to be used as a local branch name in refs/heads/.
+ *
+ * The return value is "0" if the result is valid, and "-1" otherwise.
+ */
+int strbuf_check_branch_ref(struct strbuf *sb, const char *name);
+
+/*
+ * Similar for a tag name in refs/tags/.
+ *
+ * The return value is "0" if the result is valid, and "-1" otherwise.
+ */
+int strbuf_check_tag_ref(struct strbuf *sb, const char *name);
+
 /*
  * A ref_transaction represents a collection of reference updates that
  * should succeed or fail together.

strbuf.h

@@ -637,28 +637,6 @@ static inline void strbuf_complete_line(struct strbuf *sb)
 	strbuf_complete(sb, '\n');
 }
 
-/*
- * Copy "name" to "sb", expanding any special @-marks as handled by
- * repo_interpret_branch_name(). The result is a non-qualified branch name
- * (so "foo" or "origin/master" instead of "refs/heads/foo" or
- * "refs/remotes/origin/master").
- *
- * Note that the resulting name may not be a syntactically valid refname.
- *
- * If "allowed" is non-zero, restrict the set of allowed expansions. See
- * repo_interpret_branch_name() for details.
- */
-void strbuf_branchname(struct strbuf *sb, const char *name,
-		       unsigned allowed);
-
-/*
- * Like strbuf_branchname() above, but confirm that the result is
- * syntactically valid to be used as a local branch name in refs/heads/.
- *
- * The return value is "0" if the result is valid, and "-1" otherwise.
- */
-int strbuf_check_branch_ref(struct strbuf *sb, const char *name);
-
 typedef int (*char_predicate)(char ch);
 
 void strbuf_addstr_urlencode(struct strbuf *sb, const char *name,