Automattic / jetpack

	}

	function _doHeaders_callback_setext($matches) {

		# Terrible hack to check we haven't found an empty list item.

		if ($matches[2] == '-' && preg_match('{^-(?: |$)}', $matches[1]))

			return $matches[0];

		$level = $matches[2][0] == '=' ? 1 : 2;

		$block = "<h$level>".$this->runSpanGamut($matches[1])."</h$level>";

		return $text;

	}

	function _doHeaders_callback_setext($matches) {

		if ($matches[3] == '-' && preg_match('{^- }', $matches[1]))

			return $matches[0];

		$level = $matches[3][0] == '=' ? 1 : 2;

		$attr  = $this->doExtraAttributes("h$level", $dummy =& $matches[2]);

		$block = "<h$level$attr>".$this->runSpanGamut($matches[1])."</h$level>";

		return preg_replace_callback(

			'#(<a[^>]* href=(["\']?)(\S+)\2>)\s*(<img[^>]*)(class=(["\']?)[^>]*wp-image-[0-9]+[^>]*\6.*>)\s*</a>#is',

			static function( $matches ) {

				if ( ! preg_match( '#\.\w+$#', $matches[3] ) ) {

					// The a[href] doesn't end in a file extension like .jpeg, so this is not a link to the media file, and should get a lightbox.

					return $matches[4] . ' data-amp-lightbox="true" lightbox="true" ' . $matches[5]; // https://github.com/ampproject/amp-wp/blob/1094ea03bd5dc92889405a47a8c41de1a88908de/includes/sanitizers/class-amp-img-sanitizer.php#L419.

				}

				return $matches[0];

			},