+/**
+ * Whether a registered shortcode exists named $tag
+ *
+ * @since 3.6.0
+ *
+ * @global array $shortcode_tags List of shortcode tags and their callback hooks.
+ *
+ * @param string $tag Shortcode tag to check.
+ * @return bool Whether the given shortcode exists.
+ */
+function shortcode_exists( $tag ) {
+ global $shortcode_tags;
+ return array_key_exists( $tag, $shortcode_tags );
+}
+
+/**
+ * Whether the passed content contains the specified shortcode
+ *
+ * @since 3.6.0
+ *
+ * @global array $shortcode_tags
+ *
+ * @param string $content Content to search for shortcodes.
+ * @param string $tag Shortcode tag to check.
+ * @return bool Whether the passed content contains the given shortcode.
+ */
+function has_shortcode( $content, $tag ) {
+ if ( false === strpos( $content, '[' ) ) {
+ return false;
+ }
+
+ if ( shortcode_exists( $tag ) ) {
+ preg_match_all( '/' . get_shortcode_regex() . '/s', $content, $matches, PREG_SET_ORDER );
+ if ( empty( $matches ) )
+ return false;
+
+ foreach ( $matches as $shortcode ) {
+ if ( $tag === $shortcode[2] ) {
+ return true;
+ } elseif ( ! empty( $shortcode[5] ) && has_shortcode( $shortcode[5], $tag ) ) {
+ return true;
+ }
+ }
+ }
+ return false;
+}
+