leilukin-tumbleblog/includes/lib/xenocrat/markdown/block/HtmlTrait.php

<?php
/**
 * @copyright Copyright 2014 Carsten Brandt, 2024 Daniel Pimley
 * @license https://github.com/xenocrat/chyrp-markdown/blob/master/LICENSE
 * @link https://github.com/xenocrat/chyrp-markdown#readme
 */

namespace xenocrat\markdown\block;

/**
 * Adds inline and block HTML support.
 */
trait HtmlTrait
{
	/**
	 * @var array HTML elements defined in CommonMark spec
	 * @see https://spec.commonmark.org/0.31.2/#html-blocks
	 */
	protected $type6HtmlElements = [
		'address', 'article', 'aside',
		'base', 'basefont', 'blockquote', 'body',
		'caption', 'center', 'col', 'colgroup',
		'dd', 'details', 'dialog', 'dir', 'div', 'dl', 'dt',
		'fieldset', 'figcaption', 'figure', 'footer', 'form', 'frame', 'frameset',
		'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'head', 'header', 'hr', 'html',
		'iframe',
		'legend', 'li', 'link',
		'main', 'menu', 'menuitem',
		'nav', 'noframes', 
		'ol', 'optgroup', 'option',
		'p', 'param',
		'section', 'source', 'summary',
		'table', 'tbody', 'td', 'tfoot', 'th', 'thead', 'title', 'tr', 'track',
		'ul',
	];

	/**
	 * Identify a line as the beginning of a HTML block.
	 */
	protected function identifyHtml($line, $lines, $current): bool
	{
		if (
			$line[0] === ' '
			&& strspn($line, ' ') < 4
		) {
		// Trim up to three spaces.
			$line = ltrim($line, ' ');
		}
		if ($line[0] !== '<' || isset($line[1]) && $line[1] == ' ') {
		// No tag.
			return false;
		}
		if (strncasecmp($line, '<script', 7) === 0) {
		// Type 1: script.
			return true;
		}
		if (strncasecmp($line, '<pre', 4) === 0) {
		// Type 1: pre.
			return true;
		}
		if (strncasecmp($line, '<style', 6) === 0) {
		// Type 1: style.
			return true;
		}
		if (strncasecmp($line, '<textarea', 9) === 0) {
		// Type 1: textarea.
			return true;
		}
		if (strncmp($line, '<!--', 4) === 0) {
		// Type 2: comment.
			return true;
		}
		if (strncmp($line, '<?', 2) === 0) {
		// Type 3: processor.
			return true;
		}
		if (preg_match('/^<![a-z]/i', $line)) {
		// Type 4: declaration.
			return true;
		}
		if (strncmp($line, '<![CDATA[', 9) === 0) {
		// Type 5: CDATA.
			return true;
		}

		if (!isset($patterns)) {
			static $patterns;
			$patterns = implode('|', $this->type6HtmlElements);
		}

		if (preg_match("/^<\/?($patterns)(\s|>|\/>|$)/i", $line)) {
		// Type 6.
			return true;
		}
		if (
			preg_match(
				'/^<(\/)?[a-z][a-z0-9\-]*(?(1) *| .*?)?>(\s)*$/i',
				$line,
				$matches
			)
			&& (
				!isset($lines[$current - 1])
				|| $lines[$current - 1] === ''
				|| ltrim($lines[$current - 1]) === ''
			)
		) {
		// Type 7.
			return true;
		}
		return false;
	}

	/**
	 * Consume lines for an HTML block.
	 */
	protected function consumeHtml($lines, $current): array
	{
		$content = [];
		$line = ltrim($lines[$current], ' ');

		if (strncasecmp($line, '<script', 7) === 0) {
		// Type 1: script.
			for ($i = $current, $count = count($lines); $i < $count; $i++) {
				$line = $lines[$i];
				$content[] = $line;
				if (stripos($line, '</script>') !== false) {
					break;
				}
			}
		} elseif (strncasecmp($line, '<pre', 4) === 0) {
		// Type 1: pre.
			for ($i = $current, $count = count($lines); $i < $count; $i++) {
				$line = $lines[$i];
				$content[] = $line;
				if (stripos($line, '</pre>') !== false) {
					break;
				}
			}
		} elseif (strncasecmp($line, '<style', 6) === 0) {
		// Type 1: style.
			for ($i = $current, $count = count($lines); $i < $count; $i++) {
				$line = $lines[$i];
				$content[] = $line;
				if (stripos($line, '</style>') !== false) {
					break;
				}
			}
		} elseif (strncasecmp($line, '<textarea', 9) === 0) {
		// Type 1: textarea.
			for ($i = $current, $count = count($lines); $i < $count; $i++) {
				$line = $lines[$i];
				$content[] = $line;
				if (stripos($line, '</textarea>') !== false) {
					break;
				}
			}
		} elseif (strncmp($line, '<!--', 4) === 0) {
		// Type 2: comment.
			for ($i = $current, $count = count($lines); $i < $count; $i++) {
				$line = $lines[$i];
				$content[] = $line;
				if (strpos($line, '-->') !== false) {
					break;
				}
			}
		} elseif (strncmp($line, '<?', 2) === 0) {
		// Type 3: processor.
			for ($i = $current, $count = count($lines); $i < $count; $i++) {
				$line = $lines[$i];
				$content[] = $line;
				if (strpos($line, '?>') !== false) {
					break;
				}
			}
		} elseif (strncmp($line, '<!', 2) === 0) {
		// Type 4: declaration.
			for ($i = $current, $count = count($lines); $i < $count; $i++) {
				$line = $lines[$i];
				$content[] = $line;
				if (strpos($line, '>') !== false) {
					break;
				}
			}
		} elseif (strncmp($line, '<![CDATA[', 9) === 0) {
		// Type 5: CDATA.
			for ($i = $current, $count = count($lines); $i < $count; $i++) {
				$line = $lines[$i];
				$content[] = $line;
				if (strpos($line, ']]>') !== false) {
					break;
				}
			}
		} else {
		// Type 6 or 7 tag - consume until blank line...
			$content = [];
			for ($i = $current, $count = count($lines); $i < $count; $i++) {
				$line = $lines[$i];
				if (ltrim($line) !== '') {
					$content[] = $line;
				} else {
					break;
				}
			}
		}
		$block = [
			'html',
			'content' => implode("\n", $content),
		];

		return [$block, $i];
	}

	/**
	 * Renders an HTML block.
	 */
	protected function renderHtml($block): string
	{
		return $block['content'] . "\n";
	}

	protected function parseEntityMarkers(): array
	{
		return array('&');
	}

	/**
	 * Parses an & or a HTML entity definition.
	 *
	 * @marker &
	 */
	protected function parseEntity($text): array
	{
		if (
			preg_match(
				'/^&(#[\d]{1,7}|#[x][a-f0-9]{1,6}|[\w\d]{2,});/i',
				$text,
				$matches
			)
		) {
		// HTML entity.
			return [['entity', $matches[0]], strlen($matches[0])];
		} else {
		// Just an ampersand.
			return [['text', '&amp;'], 1];
		}
	}

	/**
	 * Renders a HTML entity definition.
	 */
	protected function renderEntity($block): string
	{
		$chr = $this->unEscapeHtmlEntities(
			$block[1],
			ENT_QUOTES | ENT_SUBSTITUTE
		);

		switch ($chr) {
			case '&':
				return '&amp;';
			case '<':
				return '&lt;';
			case '>':
				return '&gt;';
			case '"':
				return '&quot;';
			default:
				return $chr;
		}
	}

	protected function parseLtMarkers(): array
	{
		return array('<');
	}

	/**
	 * Parses inline HTML.
	 *
	 * @marker <
	 */
	protected function parseLt($text): array
	{
		if (strpos($text, '>') !== false) {
			// First try bracketed link if we have LinkTrait.
			if (method_exists($this, 'parseBracketedLink')) {
				$block = $this->parseBracketedLink($text);
				if ($block[0][0] !== 'text') {
					return $block;
				}
			}
			if (
				// Comment.
				preg_match('/^<!--(-?>|.*?-->)/s', $text, $matches)
				// Processor.
				|| preg_match('/^<\?.*?\?>/s', $text, $matches)
				// Declaration.
				|| preg_match('/^<![a-z].*?>/is', $text, $matches)
				// CDATA.
				|| preg_match('/^<!\[CDATA\[.*?\]\]>/s', $text, $matches)
			) {
				return [['lt', $matches[0]], strlen($matches[0])];
			}
			if (
				// Tag.
				preg_match(
					'/^<(\/)?[a-z][a-z0-9\-]*(?(1)[ \n]*|(\/|[ \n].*?))?>/is',
					$text,
					$matches
				)
			) {
				return [['lt', $matches[0]], strlen($matches[0])];
			}
		}
		return [['text', '&lt;'], 1];
	}

	/**
	 * Renders inline HTML.
	 */
	protected function renderLt($block): string
	{
		return $block[1];
	}

	protected function parseGtMarkers(): array
	{
		return array('>');
	}

	/**
	 * Escapes `>` characters.
	 *
	 * @marker >
	 */
	protected function parseGt($text): array
	{
		return [['text', '&gt;'], 1];
	}

	protected function parseDoubleQuoteMarkers(): array
	{
		return array('"');
	}

	/**
	 * Escapes `"` characters.
	 *
	 * @marker "
	 */
	protected function parseDoubleQuote($text): array
	{
		return [['text', '&quot;'], 1];
	}

	abstract protected function unEscapeHtmlEntities($text, $flags = 0);
}