use strchrnul() in place of strchr() and strlen()

Avoid scanning strings twice, once with strchr() and then with
strlen(), by using strchrnul().

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Rohit Mani <rohit.mani@outlook.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

archive.c

@@ -259,8 +259,8 @@ static void parse_treeish_arg(const char **argv,
 	/* Remotes are only allowed to fetch actual refs */
 	if (remote) {
 		char *ref = NULL;
-		const char *colon = strchr(name, ':');
-		int refnamelen = colon ? colon - name : strlen(name);
+		const char *colon = strchrnul(name, ':');
+		int refnamelen = colon - name;
 
 		if (!dwim_ref(name, refnamelen, sha1, &ref))
 			die("no such ref: %.*s", refnamelen, name);

cache-tree.c

@@ -121,11 +121,11 @@ void cache_tree_invalidate_path(struct cache_tree *it, const char *path)
 
 	if (!it)
 		return;
-	slash = strchr(path, '/');
+	slash = strchrnul(path, '/');
+	namelen = slash - path;
 	it->entry_count = -1;
-	if (!slash) {
+	if (!*slash) {
 		int pos;
-		namelen = strlen(path);
 		pos = subtree_pos(it, path, namelen);
 		if (0 <= pos) {
 			cache_tree_free(&it->down[pos]->cache_tree);
@@ -143,7 +143,6 @@ void cache_tree_invalidate_path(struct cache_tree *it, const char *path)
 		}
 		return;
 	}
-	namelen = slash - path;
 	down = find_subtree(it, path, namelen, 0);
 	if (down)
 		cache_tree_invalidate_path(down->cache_tree, slash + 1);
@@ -554,20 +553,18 @@ static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *pat
 		const char *slash;
 		struct cache_tree_sub *sub;
 
-		slash = strchr(path, '/');
-		if (!slash)
-			slash = path + strlen(path);
+		slash = strchrnul(path, '/');
 		/* between path and slash is the name of the
 		 * subtree to look for.
 		 */
 		sub = find_subtree(it, path, slash - path, 0);
 		if (!sub)
 			return NULL;
 		it = sub->cache_tree;
-		if (slash)
+		if (*slash)
 			while (*slash && *slash == '/')
 				slash++;
-		if (!slash || !*slash)
+		if (!*slash)
 			return it; /* prefix ended with slashes */
 		path = slash;
 	}

diff.c

@@ -3365,14 +3365,11 @@ static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *va
 	if (c != '-')
 		return 0;
 	arg++;
-	eq = strchr(arg, '=');
-	if (eq)
-		len = eq - arg;
-	else
-		len = strlen(arg);
+	eq = strchrnul(arg, '=');
+	len = eq - arg;
 	if (!len || strncmp(arg, arg_long, len))
 		return 0;
-	if (eq) {
+	if (*eq) {
 		int n;
 		char *end;
 		if (!isdigit(*++eq))

fast-import.c

@@ -1485,14 +1485,11 @@ static int tree_content_set(
 	unsigned int i, n;
 	struct tree_entry *e;
 
-	slash1 = strchr(p, '/');
-	if (slash1)
-		n = slash1 - p;
-	else
-		n = strlen(p);
+	slash1 = strchrnul(p, '/');
+	n = slash1 - p;
 	if (!n)
 		die("Empty path component found in input");
-	if (!slash1 && !S_ISDIR(mode) && subtree)
+	if (!*slash1 && !S_ISDIR(mode) && subtree)
 		die("Non-directories cannot have subtrees");
 
 	if (!root->tree)
@@ -1501,7 +1498,7 @@ static int tree_content_set(
 	for (i = 0; i < t->entry_count; i++) {
 		e = t->entries[i];
 		if (e->name->str_len == n && !strncmp_icase(p, e->name->str_dat, n)) {
-			if (!slash1) {
+			if (!*slash1) {
 				if (!S_ISDIR(mode)
 						&& e->versions[1].mode == mode
 						&& !hashcmp(e->versions[1].sha1, sha1))
@@ -1552,7 +1549,7 @@ static int tree_content_set(
 	e->versions[0].mode = 0;
 	hashclr(e->versions[0].sha1);
 	t->entries[t->entry_count++] = e;
-	if (slash1) {
+	if (*slash1) {
 		e->tree = new_tree_content(8);
 		e->versions[1].mode = S_IFDIR;
 		tree_content_set(e, slash1 + 1, sha1, mode, subtree);
@@ -1576,11 +1573,8 @@ static int tree_content_remove(
 	unsigned int i, n;
 	struct tree_entry *e;
 
-	slash1 = strchr(p, '/');
-	if (slash1)
-		n = slash1 - p;
-	else
-		n = strlen(p);
+	slash1 = strchrnul(p, '/');
+	n = slash1 - p;
 
 	if (!root->tree)
 		load_tree(root);
@@ -1594,15 +1588,15 @@ static int tree_content_remove(
 	for (i = 0; i < t->entry_count; i++) {
 		e = t->entries[i];
 		if (e->name->str_len == n && !strncmp_icase(p, e->name->str_dat, n)) {
-			if (slash1 && !S_ISDIR(e->versions[1].mode))
+			if (*slash1 && !S_ISDIR(e->versions[1].mode))
 				/*
 				 * If p names a file in some subdirectory, and a
 				 * file or symlink matching the name of the
 				 * parent directory of p exists, then p cannot
 				 * exist and need not be deleted.
 				 */
 				return 1;
-			if (!slash1 || !S_ISDIR(e->versions[1].mode))
+			if (!*slash1 || !S_ISDIR(e->versions[1].mode))
 				goto del_entry;
 			if (!e->tree)
 				load_tree(e);
@@ -1644,11 +1638,8 @@ static int tree_content_get(
 	unsigned int i, n;
 	struct tree_entry *e;
 
-	slash1 = strchr(p, '/');
-	if (slash1)
-		n = slash1 - p;
-	else
-		n = strlen(p);
+	slash1 = strchrnul(p, '/');
+	n = slash1 - p;
 	if (!n && !allow_root)
 		die("Empty path component found in input");
 
@@ -1664,7 +1655,7 @@ static int tree_content_get(
 	for (i = 0; i < t->entry_count; i++) {
 		e = t->entries[i];
 		if (e->name->str_len == n && !strncmp_icase(p, e->name->str_dat, n)) {
-			if (!slash1)
+			if (!*slash1)
 				goto found_entry;
 			if (!S_ISDIR(e->versions[1].mode))
 				return 0;

match-trees.c

@@ -182,13 +182,10 @@ static int splice_tree(const unsigned char *hash1,
 	enum object_type type;
 	int status;
 
-	subpath = strchr(prefix, '/');
-	if (!subpath)
-		toplen = strlen(prefix);
-	else {
-		toplen = subpath - prefix;
+	subpath = strchrnul(prefix, '/');
+	toplen = subpath - prefix;
+	if (*subpath)
 		subpath++;
-	}
 
 	buf = read_sha1_file(hash1, &type, &sz);
 	if (!buf)
@@ -215,7 +212,7 @@ static int splice_tree(const unsigned char *hash1,
 	if (!rewrite_here)
 		die("entry %.*s not found in tree %s",
 		    toplen, prefix, sha1_to_hex(hash1));
-	if (subpath) {
+	if (*subpath) {
 		status = splice_tree(rewrite_here, subpath, hash2, subtree);
 		if (status)
 			return status;

parse-options.c

@@ -223,13 +223,10 @@ static int parse_long_opt(struct parse_opt_ctx_t *p, const char *arg,
                           const struct option *options)
 {
 	const struct option *all_opts = options;
-	const char *arg_end = strchr(arg, '=');
+	const char *arg_end = strchrnul(arg, '=');
 	const struct option *abbrev_option = NULL, *ambiguous_option = NULL;
 	int abbrev_flags = 0, ambiguous_flags = 0;
 
-	if (!arg_end)
-		arg_end = arg + strlen(arg);
-
 	for (; options->type != OPTION_END; options++) {
 		const char *rest, *long_name = options->long_name;
 		int flags = 0, opt_flags = 0;

pretty.c

@@ -549,14 +549,13 @@ static char *get_header(const struct commit *commit, const char *msg,
 	const char *line = msg;
 
 	while (line) {
-		const char *eol = strchr(line, '\n'), *next;
+		const char *eol = strchrnul(line, '\n'), *next;
 
 		if (line == eol)
 			return NULL;
-		if (!eol) {
+		if (!*eol) {
 			warning("malformed commit (header is missing newline): %s",
 				sha1_to_hex(commit->object.sha1));
-			eol = line + strlen(line);
 			next = NULL;
 		} else
 			next = eol + 1;

remote-testsvn.c

@@ -78,8 +78,8 @@ static int parse_rev_note(const char *msg, struct rev_note *res)
 	size_t len;
 
 	while (*msg) {
-		end = strchr(msg, '\n');
-		len = end ? end - msg : strlen(msg);
+		end = strchrnul(msg, '\n');
+		len = end - msg;
 
 		key = "Revision-number: ";
 		if (starts_with(msg, key)) {

ws.c

@@ -33,11 +33,8 @@ unsigned parse_whitespace_rule(const char *string)
 		int negated = 0;
 
 		string = string + strspn(string, ", \t\n\r");
-		ep = strchr(string, ',');
-		if (!ep)
-			len = strlen(string);
-		else
-			len = ep - string;
+		ep = strchrnul(string, ',');
+		len = ep - string;
 
 		if (*string == '-') {
 			negated = 1;