argv_array: offer to split a string by whitespace

This is a simple function that will interpret a string as a whitespace
delimited list of values, and add those values into the array.

Note: this function does not (yet) offer to split by arbitrary delimiters,
or keep empty values in case of runs of whitespace, or de-quote Unix shell
style. All fo this functionality can be added later, when and if needed.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

argv-array.c

@@ -64,6 +64,26 @@ void argv_array_pop(struct argv_array *array)
 	array->argc--;
 }
 
+void argv_array_split(struct argv_array *array, const char *to_split)
+{
+	while (isspace(*to_split))
+		to_split++;
+	for (;;) {
+		const char *p = to_split;
+
+		if (!*p)
+			break;
+
+		while (*p && !isspace(*p))
+			p++;
+		argv_array_push_nodup(array, xstrndup(to_split, p - to_split));
+
+		while (isspace(*p))
+			p++;
+		to_split = p;
+	}
+}
+
 void argv_array_clear(struct argv_array *array)
 {
 	if (array->argv != empty_argv) {