use strip_suffix instead of ends_with in simple cases

When stripping a suffix like:

  if (ends_with(str, "foo"))
	buf = xmemdupz(str, strlen(str) - 3);

we can instead use strip_suffix to avoid the constant 3,
which must match the literal "foo" (we sometimes use
strlen("foo") instead, but that means we are repeating
ourselves). The example above becomes:

  if (strip_suffix(str, "foo", &len))
	buf = xmemdupz(str, len);

This also saves a strlen(), since we calculate the string
length when detecting the suffix.

Note that in some cases we also switch from xstrndup to
xmemdupz, which saves a further strlen call.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/remote.c

@@ -265,16 +265,17 @@ static int config_read_branches(const char *key, const char *value, void *cb)
 		struct string_list_item *item;
 		struct branch_info *info;
 		enum { REMOTE, MERGE, REBASE } type;
+		size_t key_len;
 
 		key += 7;
-		if (ends_with(key, ".remote")) {
-			name = xstrndup(key, strlen(key) - 7);
+		if (strip_suffix(key, ".remote", &key_len)) {
+			name = xmemdupz(key, key_len);
 			type = REMOTE;
-		} else if (ends_with(key, ".merge")) {
-			name = xstrndup(key, strlen(key) - 6);
+		} else if (strip_suffix(key, ".merge", &key_len)) {
+			name = xmemdupz(key, key_len);
 			type = MERGE;
-		} else if (ends_with(key, ".rebase")) {
-			name = xstrndup(key, strlen(key) - 7);
+		} else if (strip_suffix(key, ".rebase", &key_len)) {
+			name = xmemdupz(key, key_len);
 			type = REBASE;
 		} else
 			return 0;

builtin/repack.c

@@ -77,16 +77,15 @@ static void get_non_kept_pack_filenames(struct string_list *fname_list)
 	DIR *dir;
 	struct dirent *e;
 	char *fname;
-	size_t len;
 
 	if (!(dir = opendir(packdir)))
 		return;
 
 	while ((e = readdir(dir)) != NULL) {
-		if (!ends_with(e->d_name, ".pack"))
+		size_t len;
+		if (!strip_suffix(e->d_name, ".pack", &len))
 			continue;
 
-		len = strlen(e->d_name) - strlen(".pack");
 		fname = xmemdupz(e->d_name, len);
 
 		if (!file_exists(mkpath("%s/%s.keep", packdir, fname)))

connected.c

@@ -31,17 +31,17 @@ static int check_everything_connected_real(sha1_iterate_fn fn,
 	unsigned char sha1[20];
 	int err = 0, ac = 0;
 	struct packed_git *new_pack = NULL;
+	size_t base_len;
 
 	if (fn(cb_data, sha1))
 		return err;
 
 	if (transport && transport->smart_options &&
 	    transport->smart_options->self_contained_and_connected &&
 	    transport->pack_lockfile &&
-	    ends_with(transport->pack_lockfile, ".keep")) {
+	    strip_suffix(transport->pack_lockfile, ".keep", &base_len)) {
 		struct strbuf idx_file = STRBUF_INIT;
-		strbuf_addstr(&idx_file, transport->pack_lockfile);
-		strbuf_setlen(&idx_file, idx_file.len - 5); /* ".keep" */
+		strbuf_add(&idx_file, transport->pack_lockfile, base_len);
 		strbuf_addstr(&idx_file, ".idx");
 		new_pack = add_packed_git(idx_file.buf, idx_file.len, 1);
 		strbuf_release(&idx_file);

help.c

@@ -145,7 +145,7 @@ static void list_commands_in_dir(struct cmdnames *cmds,
 	len = buf.len;
 
 	while ((de = readdir(dir)) != NULL) {
-		int entlen;
+		size_t entlen;
 
 		if (!starts_with(de->d_name, prefix))
 			continue;
@@ -156,8 +156,7 @@ static void list_commands_in_dir(struct cmdnames *cmds,
 			continue;
 
 		entlen = strlen(de->d_name) - prefix_len;
-		if (ends_with(de->d_name, ".exe"))
-			entlen -= 4;
+		strip_suffix(de->d_name, ".exe", &entlen);
 
 		add_cmdname(cmds, de->d_name + prefix_len, entlen);
 	}