Rename interpret/substitute nth_last_branch functions

These allow you to say "git checkout @{-2}" to switch to the branch two
"branch switching" ago by pretending as if you typed the name of that
branch.  As it is likely that we will be introducing more short-hands to
write the name of a branch without writing it explicitly, rename the
functions from "nth_last_branch" to more generic "branch_name", to prepare
for different semantics.

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

branch.c

@@ -137,7 +137,7 @@ void create_branch(const char *head,
 	int len;
 
 	len = strlen(name);
-	if (interpret_nth_last_branch(name, &ref) != len) {
+	if (interpret_branch_name(name, &ref) != len) {
 		strbuf_reset(&ref);
 		strbuf_add(&ref, name, len);
 	}

builtin-branch.c

@@ -123,7 +123,7 @@ static int delete_branches(int argc, const char **argv, int force, int kinds)
 	for (i = 0; i < argc; i++, strbuf_release(&bname)) {
 		int len = strlen(argv[i]);
 
-		if (interpret_nth_last_branch(argv[i], &bname) != len)
+		if (interpret_branch_name(argv[i], &bname) != len)
 			strbuf_add(&bname, argv[i], len);
 
 		if (kinds == REF_LOCAL_BRANCH && !strcmp(head, bname.buf)) {

builtin-checkout.c

@@ -355,7 +355,7 @@ static void setup_branch_path(struct branch_info *branch)
 	struct strbuf buf = STRBUF_INIT;
 	int ret;
 
-	if ((ret = interpret_nth_last_branch(branch->name, &buf))
+	if ((ret = interpret_branch_name(branch->name, &buf))
 	    && ret == strlen(branch->name)) {
 		branch->name = xstrdup(buf.buf);
 		strbuf_splice(&buf, 0, 0, "refs/heads/", 11);

builtin-merge.c

@@ -361,7 +361,7 @@ static void merge_name(const char *remote, struct strbuf *msg)
 	int len, early;
 
 	len = strlen(remote);
-	if (interpret_nth_last_branch(remote, &bname) == len)
+	if (interpret_branch_name(remote, &bname) == len)
 		remote = bname.buf;
 
 	memset(branch_head, 0, sizeof(branch_head));

cache.h

@@ -671,7 +671,7 @@ extern int read_ref(const char *filename, unsigned char *sha1);
 extern const char *resolve_ref(const char *path, unsigned char *sha1, int, int *);
 extern int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref);
 extern int dwim_log(const char *str, int len, unsigned char *sha1, char **ref);
-extern int interpret_nth_last_branch(const char *str, struct strbuf *);
+extern int interpret_branch_name(const char *str, struct strbuf *);
 
 extern int refname_match(const char *abbrev_name, const char *full_name, const char **rules);
 extern const char *ref_rev_parse_rules[];

sha1_name.c

@@ -242,10 +242,10 @@ static int ambiguous_path(const char *path, int len)
  * *string and *len will only be substituted, and *string returned (for
  * later free()ing) if the string passed in is of the form @{-<n>}.
  */
-static char *substitute_nth_last_branch(const char **string, int *len)
+static char *substitute_branch_name(const char **string, int *len)
 {
 	struct strbuf buf = STRBUF_INIT;
-	int ret = interpret_nth_last_branch(*string, &buf);
+	int ret = interpret_branch_name(*string, &buf);
 
 	if (ret == *len) {
 		size_t size;
@@ -259,7 +259,7 @@ static char *substitute_nth_last_branch(const char **string, int *len)
 
 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
 {
-	char *last_branch = substitute_nth_last_branch(&str, &len);
+	char *last_branch = substitute_branch_name(&str, &len);
 	const char **p, *r;
 	int refs_found = 0;
 
@@ -288,7 +288,7 @@ int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
 
 int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 {
-	char *last_branch = substitute_nth_last_branch(&str, &len);
+	char *last_branch = substitute_branch_name(&str, &len);
 	const char **p;
 	int logs_found = 0;
 
@@ -355,7 +355,7 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 		struct strbuf buf = STRBUF_INIT;
 		int ret;
 		/* try the @{-N} syntax for n-th checkout */
-		ret = interpret_nth_last_branch(str+at, &buf);
+		ret = interpret_branch_name(str+at, &buf);
 		if (ret > 0) {
 			/* substitute this branch name and restart */
 			return get_sha1_1(buf.buf, buf.len, sha1);
@@ -750,7 +750,7 @@ static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,
  * If the input was ok but there are not N branch switches in the
  * reflog, it returns 0.
  */
-int interpret_nth_last_branch(const char *name, struct strbuf *buf)
+int interpret_branch_name(const char *name, struct strbuf *buf)
 {
 	long nth;
 	int i, retval;