quote: implement sq_quotef()

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

quote.c

@@ -43,6 +43,19 @@ void sq_quote_buf(struct strbuf *dst, const char *src)
 	free(to_free);
 }
 
+void sq_quotef(struct strbuf *dst, const char *fmt, ...)
+{
+	struct strbuf src = STRBUF_INIT;
+
+	va_list ap;
+	va_start(ap, fmt);
+	strbuf_vaddf(&src, fmt, ap);
+	va_end(ap);
+
+	sq_quote_buf(dst, src.buf);
+	strbuf_release(&src);
+}
+
 void sq_quote_argv(struct strbuf *dst, const char** argv, size_t maxlen)
 {
 	int i;

quote.h

@@ -25,10 +25,13 @@ struct strbuf;
  * sq_quote_buf() writes to an existing buffer of specified size; it
  * will return the number of characters that would have been written
  * excluding the final null regardless of the buffer size.
+ *
+ * sq_quotef() quotes the entire formatted string as a single result.
  */
 
 extern void sq_quote_buf(struct strbuf *, const char *src);
 extern void sq_quote_argv(struct strbuf *, const char **argv, size_t maxlen);
+extern void sq_quotef(struct strbuf *, const char *fmt, ...);
 
 /* This unwraps what sq_quote() produces in place, but returns
  * NULL if the input does not look like what sq_quote would have