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<?php /** * HTML API: WP_HTML_Processor class * * @package WordPress * @subpackage HTML-API * @since 6.4.0 */ /** * Core class used to safely parse and modify an HTML document. * * The HTML Processor class properly parses and modifies HTML5 documents. * * It supports a subset of the HTML5 specification, and when it encounters * unsupported markup, it aborts early to avoid unintentionally breaking * the document. The HTML Processor should never break an HTML document. * * While the `WP_HTML_Tag_Processor` is a valuable tool for modifying * attributes on individual HTML tags, the HTML Processor is more capable * and useful for the following operations: * * - Querying based on nested HTML structure. * * Eventually the HTML Processor will also support: * - Wrapping a tag in surrounding HTML. * - Unwrapping a tag by removing its parent. * - Inserting and removing nodes. * - Reading and changing inner content. * - Navigating up or around HTML structure. * * ## Usage * * Use of this class requires three steps: * * 1. Call a static creator method with your input HTML document. * 2. Find the location in the document you are looking for. * 3. Request changes to the document at that location. * * Example: * * $processor = WP_HTML_Processor::create_fragment( $html ); * if ( $processor->next_tag( array( 'breadcrumbs' => array( 'DIV', 'FIGURE', 'IMG' ) ) ) ) { * $processor->add_class( 'responsive-image' ); * } * * #### Breadcrumbs * * Breadcrumbs represent the stack of open elements from the root * of the document or fragment down to the currently-matched node, * if one is currently selected. Call WP_HTML_Processor::get_breadcrumbs() * to inspect the breadcrumbs for a matched tag. * * Breadcrumbs can specify nested HTML structure and are equivalent * to a CSS selector comprising tag names separated by the child * combinator, such as "DIV > FIGURE > IMG". * * Since all elements find themselves inside a full HTML document * when parsed, the return value from `get_breadcrumbs()` will always * contain any implicit outermost elements. For example, when parsing * with `create_fragment()` in the `BODY` context (the default), any * tag in the given HTML document will contain `array( 'HTML', 'BODY', … )` * in its breadcrumbs. * * Despite containing the implied outermost elements in their breadcrumbs, * tags may be found with the shortest-matching breadcrumb query. That is, * `array( 'IMG' )` matches all IMG elements and `array( 'P', 'IMG' )` * matches all IMG elements directly inside a P element. To ensure that no * partial matches erroneously match it's possible to specify in a query * the full breadcrumb match all the way down from the root HTML element. * * Example: * * $html = '<figure><img><figcaption>A <em>lovely</em> day outside</figcaption></figure>'; * // ----- Matches here. * $processor->next_tag( array( 'breadcrumbs' => array( 'FIGURE', 'IMG' ) ) ); * * $html = '<figure><img><figcaption>A <em>lovely</em> day outside</figcaption></figure>'; * // ---- Matches here. * $processor->next_tag( array( 'breadcrumbs' => array( 'FIGURE', 'FIGCAPTION', 'EM' ) ) ); * * $html = '<div><img></div><img>'; * // ----- Matches here, because IMG must be a direct child of the implicit BODY. * $processor->next_tag( array( 'breadcrumbs' => array( 'BODY', 'IMG' ) ) ); * * ## HTML Support * * This class implements a small part of the HTML5 specification. * It's designed to operate within its support and abort early whenever * encountering circumstances it can't properly handle. This is * the principle way in which this class remains as simple as possible * without cutting corners and breaking compliance. * * ### Supported elements * * If any unsupported element appears in the HTML input the HTML Processor * will abort early and stop all processing. This draconian measure ensures * that the HTML Processor won't break any HTML it doesn't fully understand. * * The following list specifies the HTML tags that _are_ supported: * * - Containers: ADDRESS, BLOCKQUOTE, DETAILS, DIALOG, DIV, FOOTER, HEADER, MAIN, MENU, SPAN, SUMMARY. * - Custom elements: All custom elements are supported. :) * - Form elements: BUTTON, DATALIST, FIELDSET, INPUT, LABEL, LEGEND, METER, PROGRESS, SEARCH. * - Formatting elements: B, BIG, CODE, EM, FONT, I, PRE, SMALL, STRIKE, STRONG, TT, U, WBR. * - Heading elements: H1, H2, H3, H4, H5, H6, HGROUP. * - Links: A. * - Lists: DD, DL, DT, LI, OL, UL. * - Media elements: AUDIO, CANVAS, EMBED, FIGCAPTION, FIGURE, IMG, MAP, PICTURE, SOURCE, TRACK, VIDEO. * - Paragraph: BR, P. * - Phrasing elements: ABBR, AREA, BDI, BDO, CITE, DATA, DEL, DFN, INS, MARK, OUTPUT, Q, SAMP, SUB, SUP, TIME, VAR. * - Sectioning elements: ARTICLE, ASIDE, HR, NAV, SECTION. * - Templating elements: SLOT. * - Text decoration: RUBY. * - Deprecated elements: ACRONYM, BLINK, CENTER, DIR, ISINDEX, KEYGEN, LISTING, MULTICOL, NEXTID, PARAM, SPACER. * * ### Supported markup * * Some kinds of non-normative HTML involve reconstruction of formatting elements and * re-parenting of mis-nested elements. For example, a DIV tag found inside a TABLE * may in fact belong _before_ the table in the DOM. If the HTML Processor encounters * such a case it will stop processing. * * The following list specifies HTML markup that _is_ supported: * * - Markup involving only those tags listed above. * - Fully-balanced and non-overlapping tags. * - HTML with unexpected tag closers. * - Some unbalanced or overlapping tags. * - P tags after unclosed P tags. * - BUTTON tags after unclosed BUTTON tags. * - A tags after unclosed A tags that don't involve any active formatting elements. * * @since 6.4.0 * * @see WP_HTML_Tag_Processor * @see https://html.spec.whatwg.org/ */ class WP_HTML_Processor extends WP_HTML_Tag_Processor { /** * The maximum number of bookmarks allowed to exist at any given time. * * HTML processing requires more bookmarks than basic tag processing, * so this class constant from the Tag Processor is overwritten. * * @since 6.4.0 * * @var int */ const MAX_BOOKMARKS = 100; /** * Holds the working state of the parser, including the stack of * open elements and the stack of active formatting elements. * * Initialized in the constructor. * * @since 6.4.0 * * @var WP_HTML_Processor_State */ private $state = null; /** * Used to create unique bookmark names. * * This class sets a bookmark for every tag in the HTML document that it encounters. * The bookmark name is auto-generated and increments, starting with `1`. These are * internal bookmarks and are automatically released when the referring WP_HTML_Token * goes out of scope and is garbage-collected. * * @since 6.4.0 * * @see WP_HTML_Processor::$release_internal_bookmark_on_destruct * * @var int */ private $bookmark_counter = 0; /** * Stores an explanation for why something failed, if it did. * * @see self::get_last_error * * @since 6.4.0 * * @var string|null */ private $last_error = null; /** * Releases a bookmark when PHP garbage-collects its wrapping WP_HTML_Token instance. * * This function is created inside the class constructor so that it can be passed to * the stack of open elements and the stack of active formatting elements without * exposing it as a public method on the class. * * @since 6.4.0 * * @var closure */ private $release_internal_bookmark_on_destruct = null; /** * Stores stack events which arise during parsing of the * HTML document, which will then supply the "match" events. * * @since 6.6.0 * * @var WP_HTML_Stack_Event[] */ private $element_queue = array(); /** * Current stack event, if set, representing a matched token. * * Because the parser may internally point to a place further along in a document * than the nodes which have already been processed (some "virtual" nodes may have * appeared while scanning the HTML document), this will point at the "current" node * being processed. It comes from the front of the element queue. * * @since 6.6.0 * * @var ?WP_HTML_Stack_Event */ private $current_element = null; /** * Context node if created as a fragment parser. * * @var ?WP_HTML_Token */ private $context_node = null; /** * Whether the parser has yet processed the context node, * if created as a fragment parser. * * The context node will be initially pushed onto the stack of open elements, * but when created as a fragment parser, this context element (and the implicit * HTML document node above it) should not be exposed as a matched token or node. * * This boolean indicates whether the processor should skip over the current * node in its initial search for the first node created from the input HTML. * * @var bool */ private $has_seen_context_node = false; /* * Public Interface Functions */ /** * Creates an HTML processor in the fragment parsing mode. * * Use this for cases where you are processing chunks of HTML that * will be found within a bigger HTML document, such as rendered * block output that exists within a post, `the_content` inside a * rendered site layout. * * Fragment parsing occurs within a context, which is an HTML element * that the document will eventually be placed in. It becomes important * when special elements have different rules than others, such as inside * a TEXTAREA or a TITLE tag where things that look like tags are text, * or inside a SCRIPT tag where things that look like HTML syntax are JS. * * The context value should be a representation of the tag into which the * HTML is found. For most cases this will be the body element. The HTML * form is provided because a context element may have attributes that * impact the parse, such as with a SCRIPT tag and its `type` attribute. * * ## Current HTML Support * * - The only supported context is `<body>`, which is the default value. * - The only supported document encoding is `UTF-8`, which is the default value. * * @since 6.4.0 * @since 6.6.0 Returns `static` instead of `self` so it can create subclass instances. * * @param string $html Input HTML fragment to process. * @param string $context Context element for the fragment, must be default of `<body>`. * @param string $encoding Text encoding of the document; must be default of 'UTF-8'. * @return static|null The created processor if successful, otherwise null. */ public static function create_fragment( $html, $context = '<body>', $encoding = 'UTF-8' ) { if ( '<body>' !== $context || 'UTF-8' !== $encoding ) { return null; } $processor = new static( $html, self::CONSTRUCTOR_UNLOCK_CODE ); $processor->state->context_node = array( 'BODY', array() ); $processor->state->insertion_mode = WP_HTML_Processor_State::INSERTION_MODE_IN_BODY; // @todo Create "fake" bookmarks for non-existent but implied nodes. $processor->bookmarks['root-node'] = new WP_HTML_Span( 0, 0 ); $processor->bookmarks['context-node'] = new WP_HTML_Span( 0, 0 ); $processor->state->stack_of_open_elements->push( new WP_HTML_Token( 'root-node', 'HTML', false ) ); $context_node = new WP_HTML_Token( 'context-node', $processor->state->context_node[0], false ); $processor->state->stack_of_open_elements->push( $context_node ); $processor->context_node = $context_node; return $processor; } /** * Constructor. * * Do not use this method. Use the static creator methods instead. * * @access private * * @since 6.4.0 * * @see WP_HTML_Processor::create_fragment() * * @param string $html HTML to process. * @param string|null $use_the_static_create_methods_instead This constructor should not be called manually. */ public function __construct( $html, $use_the_static_create_methods_instead = null ) { parent::__construct( $html ); if ( self::CONSTRUCTOR_UNLOCK_CODE !== $use_the_static_create_methods_instead ) { _doing_it_wrong( __METHOD__, sprintf( /* translators: %s: WP_HTML_Processor::create_fragment(). */ __( 'Call %s to create an HTML Processor instead of calling the constructor directly.' ), '<code>WP_HTML_Processor::create_fragment()</code>' ), '6.4.0' ); } $this->state = new WP_HTML_Processor_State(); $this->state->stack_of_open_elements->set_push_handler( function ( WP_HTML_Token $token ) { $is_virtual = ! isset( $this->state->current_token ) || $this->is_tag_closer(); $same_node = isset( $this->state->current_token ) && $token->node_name === $this->state->current_token->node_name; $provenance = ( ! $same_node || $is_virtual ) ? 'virtual' : 'real'; $this->element_queue[] = new WP_HTML_Stack_Event( $token, WP_HTML_Stack_Event::PUSH, $provenance ); } ); $this->state->stack_of_open_elements->set_pop_handler( function ( WP_HTML_Token $token ) { $is_virtual = ! isset( $this->state->current_token ) || ! $this->is_tag_closer(); $same_node = isset( $this->state->current_token ) && $token->node_name === $this->state->current_token->node_name; $provenance = ( ! $same_node || $is_virtual ) ? 'virtual' : 'real'; $this->element_queue[] = new WP_HTML_Stack_Event( $token, WP_HTML_Stack_Event::POP, $provenance ); } ); /* * Create this wrapper so that it's possible to pass * a private method into WP_HTML_Token classes without * exposing it to any public API. */ $this->release_internal_bookmark_on_destruct = function ( $name ) { parent::release_bookmark( $name ); }; } /** * Returns the last error, if any. * * Various situations lead to parsing failure but this class will * return `false` in all those cases. To determine why something * failed it's possible to request the last error. This can be * helpful to know to distinguish whether a given tag couldn't * be found or if content in the document caused the processor * to give up and abort processing. * * Example * * $processor = WP_HTML_Processor::create_fragment( '<template><strong><button><em><p><em>' ); * false === $processor->next_tag(); * WP_HTML_Processor::ERROR_UNSUPPORTED === $processor->get_last_error(); * * @since 6.4.0 * * @see self::ERROR_UNSUPPORTED * @see self::ERROR_EXCEEDED_MAX_BOOKMARKS * * @return string|null The last error, if one exists, otherwise null. */ public function get_last_error() { return $this->last_error; } /** * Finds the next tag matching the $query. * * @todo Support matching the class name and tag name. * * @since 6.4.0 * @since 6.6.0 Visits all tokens, including virtual ones. * * @throws Exception When unable to allocate a bookmark for the next token in the input HTML document. * * @param array|string|null $query { * Optional. Which tag name to find, having which class, etc. Default is to find any tag. * * @type string|null $tag_name Which tag to find, or `null` for "any tag." * @type string $tag_closers 'visit' to pause at tag closers, 'skip' or unset to only visit openers. * @type int|null $match_offset Find the Nth tag matching all search criteria. * 1 for "first" tag, 3 for "third," etc. * Defaults to first tag. * @type string|null $class_name Tag must contain this whole class name to match. * @type string[] $breadcrumbs DOM sub-path at which element is found, e.g. `array( 'FIGURE', 'IMG' )`. * May also contain the wildcard `*` which matches a single element, e.g. `array( 'SECTION', '*' )`. * } * @return bool Whether a tag was matched. */ public function next_tag( $query = null ) { $visit_closers = isset( $query['tag_closers'] ) && 'visit' === $query['tag_closers']; if ( null === $query ) { while ( $this->next_token() ) { if ( '#tag' !== $this->get_token_type() ) { continue; } if ( ! $this->is_tag_closer() || $visit_closers ) { return true; } } return false; } if ( is_string( $query ) ) { $query = array( 'breadcrumbs' => array( $query ) ); } if ( ! is_array( $query ) ) { _doing_it_wrong( __METHOD__, __( 'Please pass a query array to this function.' ), '6.4.0' ); return false; } $needs_class = ( isset( $query['class_name'] ) && is_string( $query['class_name'] ) ) ? $query['class_name'] : null; if ( ! ( array_key_exists( 'breadcrumbs', $query ) && is_array( $query['breadcrumbs'] ) ) ) { while ( $this->next_token() ) { if ( '#tag' !== $this->get_token_type() ) { continue; } if ( isset( $needs_class ) && ! $this->has_class( $needs_class ) ) { continue; } if ( ! $this->is_tag_closer() || $visit_closers ) { return true; } } return false; } $breadcrumbs = $query['breadcrumbs']; $match_offset = isset( $query['match_offset'] ) ? (int) $query['match_offset'] : 1; while ( $match_offset > 0 && $this->next_token() ) { if ( '#tag' !== $this->get_token_type() || $this->is_tag_closer() ) { continue; } if ( isset( $needs_class ) && ! $this->has_class( $needs_class ) ) { continue; } if ( $this->matches_breadcrumbs( $breadcrumbs ) && 0 === --$match_offset ) { return true; } } return false; } /** * Ensures internal accounting is maintained for HTML semantic rules while * the underlying Tag Processor class is seeking to a bookmark. * * This doesn't currently have a way to represent non-tags and doesn't process * semantic rules for text nodes. For access to the raw tokens consider using * WP_HTML_Tag_Processor instead. * * @since 6.5.0 Added for internal support; do not use. * * @access private * * @return bool */ public function next_token() { $this->current_element = null; if ( isset( $this->last_error ) ) { return false; } if ( 'done' !== $this->has_seen_context_node && 0 === count( $this->element_queue ) && ! $this->step() ) { while ( 'context-node' !== $this->state->stack_of_open_elements->current_node()->bookmark_name && $this->state->stack_of_open_elements->pop() ) { continue; } $this->has_seen_context_node = 'done'; return $this->next_token(); } $this->current_element = array_shift( $this->element_queue ); while ( isset( $this->context_node ) && ! $this->has_seen_context_node ) { if ( isset( $this->current_element ) ) { if ( $this->context_node === $this->current_element->token && WP_HTML_Stack_Event::PUSH === $this->current_element->operation ) { $this->has_seen_context_node = true; return $this->next_token(); } } $this->current_element = array_shift( $this->element_queue ); } if ( ! isset( $this->current_element ) ) { if ( 'done' === $this->has_seen_context_node ) { return false; } else { return $this->next_token(); } } if ( isset( $this->context_node ) && WP_HTML_Stack_Event::POP === $this->current_element->operation && $this->context_node === $this->current_element->token ) { $this->element_queue = array(); $this->current_element = null; return false; } // Avoid sending close events for elements which don't expect a closing. if ( WP_HTML_Stack_Event::POP === $this->current_element->operation && ! static::expects_closer( $this->current_element->token ) ) { return $this->next_token(); } return true; } /** * Indicates if the current tag token is a tag closer. * * Example: * * $p = WP_HTML_Processor::create_fragment( '<div></div>' ); * $p->next_tag( array( 'tag_name' => 'div', 'tag_closers' => 'visit' ) ); * $p->is_tag_closer() === false; * * $p->next_tag( array( 'tag_name' => 'div', 'tag_closers' => 'visit' ) ); * $p->is_tag_closer() === true; * * @since 6.6.0 Subclassed for HTML Processor. * * @return bool Whether the current tag is a tag closer. */ public function is_tag_closer() { return $this->is_virtual() ? ( WP_HTML_Stack_Event::POP === $this->current_element->operation && '#tag' === $this->get_token_type() ) : parent::is_tag_closer(); } /** * Indicates if the currently-matched token is virtual, created by a stack operation * while processing HTML, rather than a token found in the HTML text itself. * * @since 6.6.0 * * @return bool Whether the current token is virtual. */ private function is_virtual() { return ( isset( $this->current_element->provenance ) && 'virtual' === $this->current_element->provenance ); } /** * Indicates if the currently-matched tag matches the given breadcrumbs. * * A "*" represents a single tag wildcard, where any tag matches, but not no tags. * * At some point this function _may_ support a `**` syntax for matching any number * of unspecified tags in the breadcrumb stack. This has been intentionally left * out, however, to keep this function simple and to avoid introducing backtracking, * which could open up surprising performance breakdowns. * * Example: * * $processor = WP_HTML_Processor::create_fragment( '<div><span><figure><img></figure></span></div>' ); * $processor->next_tag( 'img' ); * true === $processor->matches_breadcrumbs( array( 'figure', 'img' ) ); * true === $processor->matches_breadcrumbs( array( 'span', 'figure', 'img' ) ); * false === $processor->matches_breadcrumbs( array( 'span', 'img' ) ); * true === $processor->matches_breadcrumbs( array( 'span', '*', 'img' ) ); * * @since 6.4.0 * * @param string[] $breadcrumbs DOM sub-path at which element is found, e.g. `array( 'FIGURE', 'IMG' )`. * May also contain the wildcard `*` which matches a single element, e.g. `array( 'SECTION', '*' )`. * @return bool Whether the currently-matched tag is found at the given nested structure. */ public function matches_breadcrumbs( $breadcrumbs ) { // Everything matches when there are zero constraints. if ( 0 === count( $breadcrumbs ) ) { return true; } // Start at the last crumb. $crumb = end( $breadcrumbs ); if ( '*' !== $crumb && $this->get_tag() !== strtoupper( $crumb ) ) { return false; } foreach ( $this->state->stack_of_open_elements->walk_up() as $node ) { $crumb = strtoupper( current( $breadcrumbs ) ); if ( '*' !== $crumb && $node->node_name !== $crumb ) { return false; } if ( false === prev( $breadcrumbs ) ) { return true; } } return false; } /** * Indicates if the currently-matched node expects a closing * token, or if it will self-close on the next step. * * Most HTML elements expect a closer, such as a P element or * a DIV element. Others, like an IMG element are void and don't * have a closing tag. Special elements, such as SCRIPT and STYLE, * are treated just like void tags. Text nodes and self-closing * foreign content will also act just like a void tag, immediately * closing as soon as the processor advances to the next token. * * @since 6.6.0 * * @todo When adding support for foreign content, ensure that * this returns false for self-closing elements in the * SVG and MathML namespace. * * @param ?WP_HTML_Token $node Node to examine instead of current node, if provided. * @return bool Whether to expect a closer for the currently-matched node, * or `null` if not matched on any token. */ public function expects_closer( $node = null ) { $token_name = $node->node_name ?? $this->get_token_name(); if ( ! isset( $token_name ) ) { return null; } return ! ( // Comments, text nodes, and other atomic tokens. '#' === $token_name[0] || // Doctype declarations. 'html' === $token_name || // Void elements. self::is_void( $token_name ) || // Special atomic elements. in_array( $token_name, array( 'IFRAME', 'NOEMBED', 'NOFRAMES', 'SCRIPT', 'STYLE', 'TEXTAREA', 'TITLE', 'XMP' ), true ) ); } /** * Steps through the HTML document and stop at the next tag, if any. * * @since 6.4.0 * * @throws Exception When unable to allocate a bookmark for the next token in the input HTML document. * * @see self::PROCESS_NEXT_NODE * @see self::REPROCESS_CURRENT_NODE * * @param string $node_to_process Whether to parse the next node or reprocess the current node. * @return bool Whether a tag was matched. */ public function step( $node_to_process = self::PROCESS_NEXT_NODE ) { // Refuse to proceed if there was a previous error. if ( null !== $this->last_error ) { return false; } if ( self::REPROCESS_CURRENT_NODE !== $node_to_process ) { /* * Void elements still hop onto the stack of open elements even though * there's no corresponding closing tag. This is important for managing * stack-based operations such as "navigate to parent node" or checking * on an element's breadcrumbs. * * When moving on to the next node, therefore, if the bottom-most element * on the stack is a void element, it must be closed. * * @todo Once self-closing foreign elements and BGSOUND are supported, * they must also be implicitly closed here too. BGSOUND is * special since it's only self-closing if the self-closing flag * is provided in the opening tag, otherwise it expects a tag closer. */ $top_node = $this->state->stack_of_open_elements->current_node(); if ( isset( $top_node ) && ! static::expects_closer( $top_node ) ) { $this->state->stack_of_open_elements->pop(); } } if ( self::PROCESS_NEXT_NODE === $node_to_process ) { parent::next_token(); } // Finish stepping when there are no more tokens in the document. if ( WP_HTML_Tag_Processor::STATE_INCOMPLETE_INPUT === $this->parser_state || WP_HTML_Tag_Processor::STATE_COMPLETE === $this->parser_state ) { return false; } $this->state->current_token = new WP_HTML_Token( $this->bookmark_token(), $this->get_token_name(), $this->has_self_closing_flag(), $this->release_internal_bookmark_on_destruct ); try { switch ( $this->state->insertion_mode ) { case WP_HTML_Processor_State::INSERTION_MODE_IN_BODY: return $this->step_in_body(); default: $this->last_error = self::ERROR_UNSUPPORTED; throw new WP_HTML_Unsupported_Exception( "No support for parsing in the '{$this->state->insertion_mode}' state." ); } } catch ( WP_HTML_Unsupported_Exception $e ) { /* * Exceptions are used in this class to escape deep call stacks that * otherwise might involve messier calling and return conventions. */ return false; } } /** * Computes the HTML breadcrumbs for the currently-matched node, if matched. * * Breadcrumbs start at the outermost parent and descend toward the matched element. * They always include the entire path from the root HTML node to the matched element. * * @todo It could be more efficient to expose a generator-based version of this function * to avoid creating the array copy on tag iteration. If this is done, it would likely * be more useful to walk up the stack when yielding instead of starting at the top. * * Example * * $processor = WP_HTML_Processor::create_fragment( '<p><strong><em><img></em></strong></p>' ); * $processor->next_tag( 'IMG' ); * $processor->get_breadcrumbs() === array( 'HTML', 'BODY', 'P', 'STRONG', 'EM', 'IMG' ); * * @since 6.4.0 * * @return string[]|null Array of tag names representing path to matched node, if matched, otherwise NULL. */ public function get_breadcrumbs() { $breadcrumbs = array(); foreach ( $this->state->stack_of_open_elements->walk_down() as $stack_item ) { $breadcrumbs[] = $stack_item->node_name; } if ( ! $this->is_virtual() ) { return $breadcrumbs; } foreach ( $this->element_queue as $queue_item ) { if ( $this->current_element->token->bookmark_name === $queue_item->token->bookmark_name ) { break; } if ( 'context-node' === $queue_item->token->bookmark_name ) { break; } if ( 'real' === $queue_item->provenance ) { break; } if ( WP_HTML_Stack_Event::PUSH === $queue_item->operation ) { $breadcrumbs[] = $queue_item->token->node_name; } else { array_pop( $breadcrumbs ); } } if ( null !== parent::get_token_name() && ! parent::is_tag_closer() ) { array_pop( $breadcrumbs ); } // Add the virtual node we're at. if ( WP_HTML_Stack_Event::PUSH === $this->current_element->operation ) { $breadcrumbs[] = $this->current_element->token->node_name; } return $breadcrumbs; } /** * Returns the nesting depth of the current location in the document. * * Example: * * $processor = WP_HTML_Processor::create_fragment( '<div><p></p></div>' ); * // The processor starts in the BODY context, meaning it has depth from the start: HTML > BODY. * 2 === $processor->get_current_depth(); * * // Opening the DIV element increases the depth. * $processor->next_token(); * 3 === $processor->get_current_depth(); * * // Opening the P element increases the depth. * $processor->next_token(); * 4 === $processor->get_current_depth(); * * // The P element is closed during `next_token()` so the depth is decreased to reflect that. * $processor->next_token(); * 3 === $processor->get_current_depth(); * * @since 6.6.0 * * @return int Nesting-depth of current location in the document. */ public function get_current_depth() { return $this->is_virtual() ? count( $this->get_breadcrumbs() ) : $this->state->stack_of_open_elements->count(); } /** * Parses next element in the 'in body' insertion mode. * * This internal function performs the 'in body' insertion mode * logic for the generalized WP_HTML_Processor::step() function. * * @since 6.4.0 * * @throws WP_HTML_Unsupported_Exception When encountering unsupported HTML input. * * @see https://html.spec.whatwg.org/#parsing-main-inbody * @see WP_HTML_Processor::step * * @return bool Whether an element was found. */ private function step_in_body() { $token_name = $this->get_token_name(); $token_type = $this->get_token_type(); $op_sigil = '#tag' === $token_type ? ( parent::is_tag_closer() ? '-' : '+' ) : ''; $op = "{$op_sigil}{$token_name}"; switch ( $op ) { case '#comment': case '#funky-comment': case '#presumptuous-tag': $this->insert_html_element( $this->state->current_token ); return true; case '#text': $this->reconstruct_active_formatting_elements(); $current_token = $this->bookmarks[ $this->state->current_token->bookmark_name ]; /* * > A character token that is U+0000 NULL * * Any successive sequence of NULL bytes is ignored and won't * trigger active format reconstruction. Therefore, if the text * only comprises NULL bytes then the token should be ignored * here, but if there are any other characters in the stream * the active formats should be reconstructed. */ if ( 1 <= $current_token->length && "\x00" === $this->html[ $current_token->start ] && strspn( $this->html, "\x00", $current_token->start, $current_token->length ) === $current_token->length ) { // Parse error: ignore the token. return $this->step(); } /* * Whitespace-only text does not affect the frameset-ok flag. * It is probably inter-element whitespace, but it may also * contain character references which decode only to whitespace. */ $text = $this->get_modifiable_text(); if ( strlen( $text ) !== strspn( $text, " \t\n\f\r" ) ) { $this->state->frameset_ok = false; } $this->insert_html_element( $this->state->current_token ); return true; case 'html': /* * > A DOCTYPE token * > Parse error. Ignore the token. */ return $this->step(); /* * > A start tag whose tag name is "button" */ case '+BUTTON': if ( $this->state->stack_of_open_elements->has_element_in_scope( 'BUTTON' ) ) { // @todo Indicate a parse error once it's possible. This error does not impact the logic here. $this->generate_implied_end_tags(); $this->state->stack_of_open_elements->pop_until( 'BUTTON' ); } $this->reconstruct_active_formatting_elements(); $this->insert_html_element( $this->state->current_token ); $this->state->frameset_ok = false; return true; /* * > A start tag whose tag name is one of: "address", "article", "aside", * > "blockquote", "center", "details", "dialog", "dir", "div", "dl", * > "fieldset", "figcaption", "figure", "footer", "header", "hgroup", * > "main", "menu", "nav", "ol", "p", "search", "section", "summary", "ul" */ case '+ADDRESS': case '+ARTICLE': case '+ASIDE': case '+BLOCKQUOTE': case '+CENTER': case '+DETAILS': case '+DIALOG': case '+DIR': case '+DIV': case '+DL': case '+FIELDSET': case '+FIGCAPTION': case '+FIGURE': case '+FOOTER': case '+HEADER': case '+HGROUP': case '+MAIN': case '+MENU': case '+NAV': case '+OL': case '+P': case '+SEARCH': case '+SECTION': case '+SUMMARY': case '+UL': if ( $this->state->stack_of_open_elements->has_p_in_button_scope() ) { $this->close_a_p_element(); } $this->insert_html_element( $this->state->current_token ); return true; /* * > An end tag whose tag name is one of: "address", "article", "aside", "blockquote", * > "button", "center", "details", "dialog", "dir", "div", "dl", "fieldset", * > "figcaption", "figure", "footer", "header", "hgroup", "listing", "main", * > "menu", "nav", "ol", "pre", "search", "section", "summary", "ul" */ case '-ADDRESS': case '-ARTICLE': case '-ASIDE': case '-BLOCKQUOTE': case '-BUTTON': case '-CENTER': case '-DETAILS': case '-DIALOG': case '-DIR': case '-DIV': case '-DL': case '-FIELDSET': case '-FIGCAPTION': case '-FIGURE': case '-FOOTER': case '-HEADER': case '-HGROUP': case '-LISTING': case '-MAIN': case '-MENU': case '-NAV': case '-OL': case '-PRE': case '-SEARCH': case '-SECTION': case '-SUMMARY': case '-UL': if ( ! $this->state->stack_of_open_elements->has_element_in_scope( $token_name ) ) { // @todo Report parse error. // Ignore the token. return $this->step(); } $this->generate_implied_end_tags(); if ( $this->state->stack_of_open_elements->current_node()->node_name !== $token_name ) { // @todo Record parse error: this error doesn't impact parsing. } $this->state->stack_of_open_elements->pop_until( $token_name ); return true; /* * > A start tag whose tag name is one of: "h1", "h2", "h3", "h4", "h5", "h6" */ case '+H1': case '+H2': case '+H3': case '+H4': case '+H5': case '+H6': if ( $this->state->stack_of_open_elements->has_p_in_button_scope() ) { $this->close_a_p_element(); } if ( in_array( $this->state->stack_of_open_elements->current_node()->node_name, array( 'H1', 'H2', 'H3', 'H4', 'H5', 'H6' ), true ) ) { // @todo Indicate a parse error once it's possible. $this->state->stack_of_open_elements->pop(); } $this->insert_html_element( $this->state->current_token ); return true; /* * > A start tag whose tag name is one of: "pre", "listing" */ case '+PRE': case '+LISTING': if ( $this->state->stack_of_open_elements->has_p_in_button_scope() ) { $this->close_a_p_element(); } $this->insert_html_element( $this->state->current_token ); $this->state->frameset_ok = false; return true; /* * > An end tag whose tag name is one of: "h1", "h2", "h3", "h4", "h5", "h6" */ case '-H1': case '-H2': case '-H3': case '-H4': case '-H5': case '-H6': if ( ! $this->state->stack_of_open_elements->has_element_in_scope( '(internal: H1 through H6 - do not use)' ) ) { /* * This is a parse error; ignore the token. * * @todo Indicate a parse error once it's possible. */ return $this->step(); } $this->generate_implied_end_tags(); if ( $this->state->stack_of_open_elements->current_node()->node_name !== $token_name ) { // @todo Record parse error: this error doesn't impact parsing. } $this->state->stack_of_open_elements->pop_until( '(internal: H1 through H6 - do not use)' ); return true; /* * > A start tag whose tag name is "li" * > A start tag whose tag name is one of: "dd", "dt" */ case '+DD': case '+DT': case '+LI': $this->state->frameset_ok = false; $node = $this->state->stack_of_open_elements->current_node(); $is_li = 'LI' === $token_name; in_body_list_loop: /* * The logic for LI and DT/DD is the same except for one point: LI elements _only_ * close other LI elements, but a DT or DD element closes _any_ open DT or DD element. */ if ( $is_li ? 'LI' === $node->node_name : ( 'DD' === $node->node_name || 'DT' === $node->node_name ) ) { $node_name = $is_li ? 'LI' : $node->node_name; $this->generate_implied_end_tags( $node_name ); if ( $node_name !== $this->state->stack_of_open_elements->current_node()->node_name ) { // @todo Indicate a parse error once it's possible. This error does not impact the logic here. } $this->state->stack_of_open_elements->pop_until( $node_name ); goto in_body_list_done; } if ( 'ADDRESS' !== $node->node_name && 'DIV' !== $node->node_name && 'P' !== $node->node_name && $this->is_special( $node->node_name ) ) { /* * > If node is in the special category, but is not an address, div, * > or p element, then jump to the step labeled done below. */ goto in_body_list_done; } else { /* * > Otherwise, set node to the previous entry in the stack of open elements * > and return to the step labeled loop. */ foreach ( $this->state->stack_of_open_elements->walk_up( $node ) as $item ) { $node = $item; break; } goto in_body_list_loop; } in_body_list_done: if ( $this->state->stack_of_open_elements->has_p_in_button_scope() ) { $this->close_a_p_element(); } $this->insert_html_element( $this->state->current_token ); return true; /* * > An end tag whose tag name is "li" * > An end tag whose tag name is one of: "dd", "dt" */ case '-DD': case '-DT': case '-LI': if ( /* * An end tag whose tag name is "li": * If the stack of open elements does not have an li element in list item scope, * then this is a parse error; ignore the token. */ ( 'LI' === $token_name && ! $this->state->stack_of_open_elements->has_element_in_list_item_scope( 'LI' ) ) || /* * An end tag whose tag name is one of: "dd", "dt": * If the stack of open elements does not have an element in scope that is an * HTML element with the same tag name as that of the token, then this is a * parse error; ignore the token. */ ( 'LI' !== $token_name && ! $this->state->stack_of_open_elements->has_element_in_scope( $token_name ) ) ) { /* * This is a parse error, ignore the token. * * @todo Indicate a parse error once it's possible. */ return $this->step(); } $this->generate_implied_end_tags( $token_name ); if ( $token_name !== $this->state->stack_of_open_elements->current_node()->node_name ) { // @todo Indicate a parse error once it's possible. This error does not impact the logic here. } $this->state->stack_of_open_elements->pop_until( $token_name ); return true; /* * > An end tag whose tag name is "p" */ case '-P': if ( ! $this->state->stack_of_open_elements->has_p_in_button_scope() ) { $this->insert_html_element( $this->state->current_token ); } $this->close_a_p_element(); return true; // > A start tag whose tag name is "a" case '+A': foreach ( $this->state->active_formatting_elements->walk_up() as $item ) { switch ( $item->node_name ) { case 'marker': break; case 'A': $this->run_adoption_agency_algorithm(); $this->state->active_formatting_elements->remove_node( $item ); $this->state->stack_of_open_elements->remove_node( $item ); break; } } $this->reconstruct_active_formatting_elements(); $this->insert_html_element( $this->state->current_token ); $this->state->active_formatting_elements->push( $this->state->current_token ); return true; /* * > A start tag whose tag name is one of: "b", "big", "code", "em", "font", "i", * > "s", "small", "strike", "strong", "tt", "u" */ case '+B': case '+BIG': case '+CODE': case '+EM': case '+FONT': case '+I': case '+S': case '+SMALL': case '+STRIKE': case '+STRONG': case '+TT': case '+U': $this->reconstruct_active_formatting_elements(); $this->insert_html_element( $this->state->current_token ); $this->state->active_formatting_elements->push( $this->state->current_token ); return true; /* * > An end tag whose tag name is one of: "a", "b", "big", "code", "em", "font", "i", * > "nobr", "s", "small", "strike", "strong", "tt", "u" */ case '-A': case '-B': case '-BIG': case '-CODE': case '-EM': case '-FONT': case '-I': case '-S': case '-SMALL': case '-STRIKE': case '-STRONG': case '-TT': case '-U': $this->run_adoption_agency_algorithm(); return true; /* * > An end tag whose tag name is "br" * > Parse error. Drop the attributes from the token, and act as described in the next * > entry; i.e. act as if this was a "br" start tag token with no attributes, rather * > than the end tag token that it actually is. */ case '-BR': $this->last_error = self::ERROR_UNSUPPORTED; throw new WP_HTML_Unsupported_Exception( 'Closing BR tags require unimplemented special handling.' ); /* * > A start tag whose tag name is one of: "area", "br", "embed", "img", "keygen", "wbr" */ case '+AREA': case '+BR': case '+EMBED': case '+IMG': case '+KEYGEN': case '+WBR': $this->reconstruct_active_formatting_elements(); $this->insert_html_element( $this->state->current_token ); $this->state->frameset_ok = false; return true; /* * > A start tag whose tag name is "input" */ case '+INPUT': $this->reconstruct_active_formatting_elements(); $this->insert_html_element( $this->state->current_token ); $type_attribute = $this->get_attribute( 'type' ); /* * > If the token does not have an attribute with the name "type", or if it does, * > but that attribute's value is not an ASCII case-insensitive match for the * > string "hidden", then: set the frameset-ok flag to "not ok". */ if ( ! is_string( $type_attribute ) || 'hidden' !== strtolower( $type_attribute ) ) { $this->state->frameset_ok = false; } return true; /* * > A start tag whose tag name is "hr" */ case '+HR': if ( $this->state->stack_of_open_elements->has_p_in_button_scope() ) { $this->close_a_p_element(); } $this->insert_html_element( $this->state->current_token ); $this->state->frameset_ok = false; return true; /* * > A start tag whose tag name is one of: "param", "source", "track" */ case '+PARAM': case '+SOURCE': case '+TRACK': $this->insert_html_element( $this->state->current_token ); return true; } /* * These tags require special handling in the 'in body' insertion mode * but that handling hasn't yet been implemented. * * As the rules for each tag are implemented, the corresponding tag * name should be removed from this list. An accompanying test should * help ensure this list is maintained. * * @see Tests_HtmlApi_WpHtmlProcessor::test_step_in_body_fails_on_unsupported_tags * * Since this switch structure throws a WP_HTML_Unsupported_Exception, it's * possible to handle "any other start tag" and "any other end tag" below, * as that guarantees execution doesn't proceed for the unimplemented tags. * * @see https://html.spec.whatwg.org/multipage/parsing.html#parsing-main-inbody */ switch ( $token_name ) { case 'APPLET': case 'BASE': case 'BASEFONT': case 'BGSOUND': case 'BODY': case 'CAPTION': case 'COL': case 'COLGROUP': case 'FORM': case 'FRAME': case 'FRAMESET': case 'HEAD': case 'HTML': case 'IFRAME': case 'LINK': case 'MARQUEE': case 'MATH': case 'META': case 'NOBR': case 'NOEMBED': case 'NOFRAMES': case 'NOSCRIPT': case 'OBJECT': case 'OPTGROUP': case 'OPTION': case 'PLAINTEXT': case 'RB': case 'RP': case 'RT': case 'RTC': case 'SARCASM': case 'SCRIPT': case 'SELECT': case 'STYLE': case 'SVG': case 'TABLE': case 'TBODY': case 'TD': case 'TEMPLATE': case 'TEXTAREA': case 'TFOOT': case 'TH': case 'THEAD': case 'TITLE': case 'TR': case 'XMP': $this->last_error = self::ERROR_UNSUPPORTED; throw new WP_HTML_Unsupported_Exception( "Cannot process {$token_name} element." ); } if ( ! parent::is_tag_closer() ) { /* * > Any other start tag */ $this->reconstruct_active_formatting_elements(); $this->insert_html_element( $this->state->current_token ); return true; } else { /* * > Any other end tag */ /* * Find the corresponding tag opener in the stack of open elements, if * it exists before reaching a special element, which provides a kind * of boundary in the stack. For example, a `</custom-tag>` should not * close anything beyond its containing `P` or `DIV` element. */ foreach ( $this->state->stack_of_open_elements->walk_up() as $node ) { if ( $token_name === $node->node_name ) { break; } if ( self::is_special( $node->node_name ) ) { // This is a parse error, ignore the token. return $this->step(); } } $this->generate_implied_end_tags( $token_name ); if ( $node !== $this->state->stack_of_open_elements->current_node() ) { // @todo Record parse error: this error doesn't impact parsing. } foreach ( $this->state->stack_of_open_elements->walk_up() as $item ) { $this->state->stack_of_open_elements->pop(); if ( $node === $item ) { return true; } } } } /* * Internal helpers */ /** * Creates a new bookmark for the currently-matched token and returns the generated name. * * @since 6.4.0 * @since 6.5.0 Renamed from bookmark_tag() to bookmark_token(). * * @throws Exception When unable to allocate requested bookmark. * * @return string|false Name of created bookmark, or false if unable to create. */ private function bookmark_token() { if ( ! parent::set_bookmark( ++$this->bookmark_counter ) ) { $this->last_error = self::ERROR_EXCEEDED_MAX_BOOKMARKS; throw new Exception( 'could not allocate bookmark' ); } return "{$this->bookmark_counter}"; } /* * HTML semantic overrides for Tag Processor */ /** * Returns the uppercase name of the matched tag. * * The semantic rules for HTML specify that certain tags be reprocessed * with a different tag name. Because of this, the tag name presented * by the HTML Processor may differ from the one reported by the HTML * Tag Processor, which doesn't apply these semantic rules. * * Example: * * $processor = new WP_HTML_Tag_Processor( '<div class="test">Test</div>' ); * $processor->next_tag() === true; * $processor->get_tag() === 'DIV'; * * $processor->next_tag() === false; * $processor->get_tag() === null; * * @since 6.4.0 * * @return string|null Name of currently matched tag in input HTML, or `null` if none found. */ public function get_tag() { if ( null !== $this->last_error ) { return null; } if ( $this->is_virtual() ) { return $this->current_element->token->node_name; } $tag_name = parent::get_tag(); switch ( $tag_name ) { case 'IMAGE': /* * > A start tag whose tag name is "image" * > Change the token's tag name to "img" and reprocess it. (Don't ask.) */ return 'IMG'; default: return $tag_name; } } /** * Indicates if the currently matched tag contains the self-closing flag. * * No HTML elements ought to have the self-closing flag and for those, the self-closing * flag will be ignored. For void elements this is benign because they "self close" * automatically. For non-void HTML elements though problems will appear if someone * intends to use a self-closing element in place of that element with an empty body. * For HTML foreign elements and custom elements the self-closing flag determines if * they self-close or not. * * This function does not determine if a tag is self-closing, * but only if the self-closing flag is present in the syntax. * * @since 6.6.0 Subclassed for the HTML Processor. * * @return bool Whether the currently matched tag contains the self-closing flag. */ public function has_self_closing_flag() { return $this->is_virtual() ? false : parent::has_self_closing_flag(); } /** * Returns the node name represented by the token. * * This matches the DOM API value `nodeName`. Some values * are static, such as `#text` for a text node, while others * are dynamically generated from the token itself. * * Dynamic names: * - Uppercase tag name for tag matches. * - `html` for DOCTYPE declarations. * * Note that if the Tag Processor is not matched on a token * then this function will return `null`, either because it * hasn't yet found a token or because it reached the end * of the document without matching a token. * * @since 6.6.0 Subclassed for the HTML Processor. * * @return string|null Name of the matched token. */ public function get_token_name() { return $this->is_virtual() ? $this->current_element->token->node_name : parent::get_token_name(); } /** * Indicates the kind of matched token, if any. * * This differs from `get_token_name()` in that it always * returns a static string indicating the type, whereas * `get_token_name()` may return values derived from the * token itself, such as a tag name or processing * instruction tag. * * Possible values: * - `#tag` when matched on a tag. * - `#text` when matched on a text node. * - `#cdata-section` when matched on a CDATA node. * - `#comment` when matched on a comment. * - `#doctype` when matched on a DOCTYPE declaration. * - `#presumptuous-tag` when matched on an empty tag closer. * - `#funky-comment` when matched on a funky comment. * * @since 6.6.0 Subclassed for the HTML Processor. * * @return string|null What kind of token is matched, or null. */ public function get_token_type() { if ( $this->is_virtual() ) { /* * This logic comes from the Tag Processor. * * @todo It would be ideal not to repeat this here, but it's not clearly * better to allow passing a token name to `get_token_type()`. */ $node_name = $this->current_element->token->node_name; $starting_char = $node_name[0]; if ( 'A' <= $starting_char && 'Z' >= $starting_char ) { return '#tag'; } if ( 'html' === $node_name ) { return '#doctype'; } return $node_name; } return parent::get_token_type(); } /** * Returns the value of a requested attribute from a matched tag opener if that attribute exists. * * Example: * * $p = WP_HTML_Processor::create_fragment( '<div enabled class="test" data-test-id="14">Test</div>' ); * $p->next_token() === true; * $p->get_attribute( 'data-test-id' ) === '14'; * $p->get_attribute( 'enabled' ) === true; * $p->get_attribute( 'aria-label' ) === null; * * $p->next_tag() === false; * $p->get_attribute( 'class' ) === null; * * @since 6.6.0 Subclassed for HTML Processor. * * @param string $name Name of attribute whose value is requested. * @return string|true|null Value of attribute or `null` if not available. Boolean attributes return `true`. */ public function get_attribute( $name ) { return $this->is_virtual() ? null : parent::get_attribute( $name ); } /** * Updates or creates a new attribute on the currently matched tag with the passed value. * * For boolean attributes special handling is provided: * - When `true` is passed as the value, then only the attribute name is added to the tag. * - When `false` is passed, the attribute gets removed if it existed before. * * For string attributes, the value is escaped using the `esc_attr` function. * * @since 6.6.0 Subclassed for the HTML Processor. * * @param string $name The attribute name to target. * @param string|bool $value The new attribute value. * @return bool Whether an attribute value was set. */ public function set_attribute( $name, $value ) { return $this->is_virtual() ? false : parent::set_attribute( $name, $value ); } /** * Remove an attribute from the currently-matched tag. * * @since 6.6.0 Subclassed for HTML Processor. * * @param string $name The attribute name to remove. * @return bool Whether an attribute was removed. */ public function remove_attribute( $name ) { return $this->is_virtual() ? false : parent::remove_attribute( $name ); } /** * Gets lowercase names of all attributes matching a given prefix in the current tag. * * Note that matching is case-insensitive. This is in accordance with the spec: * * > There must never be two or more attributes on * > the same start tag whose names are an ASCII * > case-insensitive match for each other. * - HTML 5 spec * * Example: * * $p = new WP_HTML_Tag_Processor( '<div data-ENABLED class="test" DATA-test-id="14">Test</div>' ); * $p->next_tag( array( 'class_name' => 'test' ) ) === true; * $p->get_attribute_names_with_prefix( 'data-' ) === array( 'data-enabled', 'data-test-id' ); * * $p->next_tag() === false; * $p->get_attribute_names_with_prefix( 'data-' ) === null; * * @since 6.6.0 Subclassed for the HTML Processor. * * @see https://html.spec.whatwg.org/multipage/syntax.html#attributes-2:ascii-case-insensitive * * @param string $prefix Prefix of requested attribute names. * @return array|null List of attribute names, or `null` when no tag opener is matched. */ public function get_attribute_names_with_prefix( $prefix ) { return $this->is_virtual() ? null : parent::get_attribute_names_with_prefix( $prefix ); } /** * Adds a new class name to the currently matched tag. * * @since 6.6.0 Subclassed for the HTML Processor. * * @param string $class_name The class name to add. * @return bool Whether the class was set to be added. */ public function add_class( $class_name ) { return $this->is_virtual() ? false : parent::add_class( $class_name ); } /** * Removes a class name from the currently matched tag. * * @since 6.6.0 Subclassed for the HTML Processor. * * @param string $class_name The class name to remove. * @return bool Whether the class was set to be removed. */ public function remove_class( $class_name ) { return $this->is_virtual() ? false : parent::remove_class( $class_name ); } /** * Returns if a matched tag contains the given ASCII case-insensitive class name. * * @since 6.6.0 Subclassed for the HTML Processor. * * @param string $wanted_class Look for this CSS class name, ASCII case-insensitive. * @return bool|null Whether the matched tag contains the given class name, or null if not matched. */ public function has_class( $wanted_class ) { return $this->is_virtual() ? null : parent::has_class( $wanted_class ); } /** * Generator for a foreach loop to step through each class name for the matched tag. * * This generator function is designed to be used inside a "foreach" loop. * * Example: * * $p = WP_HTML_Processor::create_fragment( "<div class='free <egg<\tlang-en'>" ); * $p->next_tag(); * foreach ( $p->class_list() as $class_name ) { * echo "{$class_name} "; * } * // Outputs: "free <egg> lang-en " * * @since 6.6.0 Subclassed for the HTML Processor. */ public function class_list() { return $this->is_virtual() ? null : parent::class_list(); } /** * Returns the modifiable text for a matched token, or an empty string. * * Modifiable text is text content that may be read and changed without * changing the HTML structure of the document around it. This includes * the contents of `#text` nodes in the HTML as well as the inner * contents of HTML comments, Processing Instructions, and others, even * though these nodes aren't part of a parsed DOM tree. They also contain * the contents of SCRIPT and STYLE tags, of TEXTAREA tags, and of any * other section in an HTML document which cannot contain HTML markup (DATA). * * If a token has no modifiable text then an empty string is returned to * avoid needless crashing or type errors. An empty string does not mean * that a token has modifiable text, and a token with modifiable text may * have an empty string (e.g. a comment with no contents). * * @since 6.6.0 Subclassed for the HTML Processor. * * @return string */ public function get_modifiable_text() { return $this->is_virtual() ? '' : parent::get_modifiable_text(); } /** * Indicates what kind of comment produced the comment node. * * Because there are different kinds of HTML syntax which produce * comments, the Tag Processor tracks and exposes this as a type * for the comment. Nominally only regular HTML comments exist as * they are commonly known, but a number of unrelated syntax errors * also produce comments. * * @see self::COMMENT_AS_ABRUPTLY_CLOSED_COMMENT * @see self::COMMENT_AS_CDATA_LOOKALIKE * @see self::COMMENT_AS_INVALID_HTML * @see self::COMMENT_AS_HTML_COMMENT * @see self::COMMENT_AS_PI_NODE_LOOKALIKE * * @since 6.6.0 Subclassed for the HTML Processor. * * @return string|null */ public function get_comment_type() { return $this->is_virtual() ? null : parent::get_comment_type(); } /** * Removes a bookmark that is no longer needed. * * Releasing a bookmark frees up the small * performance overhead it requires. * * @since 6.4.0 * * @param string $bookmark_name Name of the bookmark to remove. * @return bool Whether the bookmark already existed before removal. */ public function release_bookmark( $bookmark_name ) { return parent::release_bookmark( "_{$bookmark_name}" ); } /** * Moves the internal cursor in the HTML Processor to a given bookmark's location. * * Be careful! Seeking backwards to a previous location resets the parser to the * start of the document and reparses the entire contents up until it finds the * sought-after bookmarked location. * * In order to prevent accidental infinite loops, there's a * maximum limit on the number of times seek() can be called. * * @throws Exception When unable to allocate a bookmark for the next token in the input HTML document. * * @since 6.4.0 * * @param string $bookmark_name Jump to the place in the document identified by this bookmark name. * @return bool Whether the internal cursor was successfully moved to the bookmark's location. */ public function seek( $bookmark_name ) { // Flush any pending updates to the document before beginning. $this->get_updated_html(); $actual_bookmark_name = "_{$bookmark_name}"; $processor_started_at = $this->state->current_token ? $this->bookmarks[ $this->state->current_token->bookmark_name ]->start : 0; $bookmark_starts_at = $this->bookmarks[ $actual_bookmark_name ]->start; $bookmark_length = $this->bookmarks[ $actual_bookmark_name ]->length; $direction = $bookmark_starts_at > $processor_started_at ? 'forward' : 'backward'; /* * If seeking backwards, it's possible that the sought-after bookmark exists within an element * which has been closed before the current cursor; in other words, it has already been removed * from the stack of open elements. This means that it's insufficient to simply pop off elements * from the stack of open elements which appear after the bookmarked location and then jump to * that location, as the elements which were open before won't be re-opened. * * In order to maintain consistency, the HTML Processor rewinds to the start of the document * and reparses everything until it finds the sought-after bookmark. * * There are potentially better ways to do this: cache the parser state for each bookmark and * restore it when seeking; store an immutable and idempotent register of where elements open * and close. * * If caching the parser state it will be essential to properly maintain the cached stack of * open elements and active formatting elements when modifying the document. This could be a * tedious and time-consuming process as well, and so for now will not be performed. * * It may be possible to track bookmarks for where elements open and close, and in doing so * be able to quickly recalculate breadcrumbs for any element in the document. It may even * be possible to remove the stack of open elements and compute it on the fly this way. * If doing this, the parser would need to track the opening and closing locations for all * tokens in the breadcrumb path for any and all bookmarks. By utilizing bookmarks themselves * this list could be automatically maintained while modifying the document. Finding the * breadcrumbs would then amount to traversing that list from the start until the token * being inspected. Once an element closes, if there are no bookmarks pointing to locations * within that element, then all of these locations may be forgotten to save on memory use * and computation time. */ if ( 'backward' === $direction ) { /* * Instead of clearing the parser state and starting fresh, calling the stack methods * maintains the proper flags in the parser. */ foreach ( $this->state->stack_of_open_elements->walk_up() as $item ) { if ( 'context-node' === $item->bookmark_name ) { break; } $this->state->stack_of_open_elements->remove_node( $item ); } foreach ( $this->state->active_formatting_elements->walk_up() as $item ) { if ( 'context-node' === $item->bookmark_name ) { break; } $this->state->active_formatting_elements->remove_node( $item ); } parent::seek( 'context-node' ); $this->state->insertion_mode = WP_HTML_Processor_State::INSERTION_MODE_IN_BODY; $this->state->frameset_ok = true; $this->element_queue = array(); $this->current_element = null; } // When moving forwards, reparse the document until reaching the same location as the original bookmark. if ( $bookmark_starts_at === $this->bookmarks[ $this->state->current_token->bookmark_name ]->start ) { return true; } while ( $this->next_token() ) { if ( $bookmark_starts_at === $this->bookmarks[ $this->state->current_token->bookmark_name ]->start ) { while ( isset( $this->current_element ) && WP_HTML_Stack_Event::POP === $this->current_element->operation ) { $this->current_element = array_shift( $this->element_queue ); } return true; } } return false; } /** * Sets a bookmark in the HTML document. * * Bookmarks represent specific places or tokens in the HTML * document, such as a tag opener or closer. When applying * edits to a document, such as setting an attribute, the * text offsets of that token may shift; the bookmark is * kept updated with those shifts and remains stable unless * the entire span of text in which the token sits is removed. * * Release bookmarks when they are no longer needed. * * Example: * * <main><h2>Surprising fact you may not know!</h2></main> * ^ ^ * \-|-- this `H2` opener bookmark tracks the token * * <main class="clickbait"><h2>Surprising fact you may no… * ^ ^ * \-|-- it shifts with edits * * Bookmarks provide the ability to seek to a previously-scanned * place in the HTML document. This avoids the need to re-scan * the entire document. * * Example: * * <ul><li>One</li><li>Two</li><li>Three</li></ul> * ^^^^ * want to note this last item * * $p = new WP_HTML_Tag_Processor( $html ); * $in_list = false; * while ( $p->next_tag( array( 'tag_closers' => $in_list ? 'visit' : 'skip' ) ) ) { * if ( 'UL' === $p->get_tag() ) { * if ( $p->is_tag_closer() ) { * $in_list = false; * $p->set_bookmark( 'resume' ); * if ( $p->seek( 'last-li' ) ) { * $p->add_class( 'last-li' ); * } * $p->seek( 'resume' ); * $p->release_bookmark( 'last-li' ); * $p->release_bookmark( 'resume' ); * } else { * $in_list = true; * } * } * * if ( 'LI' === $p->get_tag() ) { * $p->set_bookmark( 'last-li' ); * } * } * * Bookmarks intentionally hide the internal string offsets * to which they refer. They are maintained internally as * updates are applied to the HTML document and therefore * retain their "position" - the location to which they * originally pointed. The inability to use bookmarks with * functions like `substr` is therefore intentional to guard * against accidentally breaking the HTML. * * Because bookmarks allocate memory and require processing * for every applied update, they are limited and require * a name. They should not be created with programmatically-made * names, such as "li_{$index}" with some loop. As a general * rule they should only be created with string-literal names * like "start-of-section" or "last-paragraph". * * Bookmarks are a powerful tool to enable complicated behavior. * Consider double-checking that you need this tool if you are * reaching for it, as inappropriate use could lead to broken * HTML structure or unwanted processing overhead. * * @since 6.4.0 * * @param string $bookmark_name Identifies this particular bookmark. * @return bool Whether the bookmark was successfully created. */ public function set_bookmark( $bookmark_name ) { return parent::set_bookmark( "_{$bookmark_name}" ); } /** * Checks whether a bookmark with the given name exists. * * @since 6.5.0 * * @param string $bookmark_name Name to identify a bookmark that potentially exists. * @return bool Whether that bookmark exists. */ public function has_bookmark( $bookmark_name ) { return parent::has_bookmark( "_{$bookmark_name}" ); } /* * HTML Parsing Algorithms */ /** * Closes a P element. * * @since 6.4.0 * * @throws WP_HTML_Unsupported_Exception When encountering unsupported HTML input. * * @see https://html.spec.whatwg.org/#close-a-p-element */ private function close_a_p_element() { $this->generate_implied_end_tags( 'P' ); $this->state->stack_of_open_elements->pop_until( 'P' ); } /** * Closes elements that have implied end tags. * * @since 6.4.0 * * @see https://html.spec.whatwg.org/#generate-implied-end-tags * * @param string|null $except_for_this_element Perform as if this element doesn't exist in the stack of open elements. */ private function generate_implied_end_tags( $except_for_this_element = null ) { $elements_with_implied_end_tags = array( 'DD', 'DT', 'LI', 'P', ); $current_node = $this->state->stack_of_open_elements->current_node(); while ( $current_node && $current_node->node_name !== $except_for_this_element && in_array( $this->state->stack_of_open_elements->current_node(), $elements_with_implied_end_tags, true ) ) { $this->state->stack_of_open_elements->pop(); } } /** * Closes elements that have implied end tags, thoroughly. * * See the HTML specification for an explanation why this is * different from generating end tags in the normal sense. * * @since 6.4.0 * * @see WP_HTML_Processor::generate_implied_end_tags * @see https://html.spec.whatwg.org/#generate-implied-end-tags */ private function generate_implied_end_tags_thoroughly() { $elements_with_implied_end_tags = array( 'DD', 'DT', 'LI', 'P', ); while ( in_array( $this->state->stack_of_open_elements->current_node(), $elements_with_implied_end_tags, true ) ) { $this->state->stack_of_open_elements->pop(); } } /** * Reconstructs the active formatting elements. * * > This has the effect of reopening all the formatting elements that were opened * > in the current body, cell, or caption (whichever is youngest) that haven't * > been explicitly closed. * * @since 6.4.0 * * @throws WP_HTML_Unsupported_Exception When encountering unsupported HTML input. * * @see https://html.spec.whatwg.org/#reconstruct-the-active-formatting-elements * * @return bool Whether any formatting elements needed to be reconstructed. */ private function reconstruct_active_formatting_elements() { /* * > If there are no entries in the list of active formatting elements, then there is nothing * > to reconstruct; stop this algorithm. */ if ( 0 === $this->state->active_formatting_elements->count() ) { return false; } $last_entry = $this->state->active_formatting_elements->current_node(); if ( /* * > If the last (most recently added) entry in the list of active formatting elements is a marker; * > stop this algorithm. */ 'marker' === $last_entry->node_name || /* * > If the last (most recently added) entry in the list of active formatting elements is an * > element that is in the stack of open elements, then there is nothing to reconstruct; * > stop this algorithm. */ $this->state->stack_of_open_elements->contains_node( $last_entry ) ) { return false; } $this->last_error = self::ERROR_UNSUPPORTED; throw new WP_HTML_Unsupported_Exception( 'Cannot reconstruct active formatting elements when advancing and rewinding is required.' ); } /** * Runs the adoption agency algorithm. * * @since 6.4.0 * * @throws WP_HTML_Unsupported_Exception When encountering unsupported HTML input. * * @see https://html.spec.whatwg.org/#adoption-agency-algorithm */ private function run_adoption_agency_algorithm() { $budget = 1000; $subject = $this->get_tag(); $current_node = $this->state->stack_of_open_elements->current_node(); if ( // > If the current node is an HTML element whose tag name is subject $current_node && $subject === $current_node->node_name && // > the current node is not in the list of active formatting elements ! $this->state->active_formatting_elements->contains_node( $current_node ) ) { $this->state->stack_of_open_elements->pop(); return; } $outer_loop_counter = 0; while ( $budget-- > 0 ) { if ( $outer_loop_counter++ >= 8 ) { return; } /* * > Let formatting element be the last element in the list of active formatting elements that: * > - is between the end of the list and the last marker in the list, * > if any, or the start of the list otherwise, * > - and has the tag name subject. */ $formatting_element = null; foreach ( $this->state->active_formatting_elements->walk_up() as $item ) { if ( 'marker' === $item->node_name ) { break; } if ( $subject === $item->node_name ) { $formatting_element = $item; break; } } // > If there is no such element, then return and instead act as described in the "any other end tag" entry above. if ( null === $formatting_element ) { $this->last_error = self::ERROR_UNSUPPORTED; throw new WP_HTML_Unsupported_Exception( 'Cannot run adoption agency when "any other end tag" is required.' ); } // > If formatting element is not in the stack of open elements, then this is a parse error; remove the element from the list, and return. if ( ! $this->state->stack_of_open_elements->contains_node( $formatting_element ) ) { $this->state->active_formatting_elements->remove_node( $formatting_element ); return; } // > If formatting element is in the stack of open elements, but the element is not in scope, then this is a parse error; return. if ( ! $this->state->stack_of_open_elements->has_element_in_scope( $formatting_element->node_name ) ) { return; } /* * > Let furthest block be the topmost node in the stack of open elements that is lower in the stack * > than formatting element, and is an element in the special category. There might not be one. */ $is_above_formatting_element = true; $furthest_block = null; foreach ( $this->state->stack_of_open_elements->walk_down() as $item ) { if ( $is_above_formatting_element && $formatting_element->bookmark_name !== $item->bookmark_name ) { continue; } if ( $is_above_formatting_element ) { $is_above_formatting_element = false; continue; } if ( self::is_special( $item->node_name ) ) { $furthest_block = $item; break; } } /* * > If there is no furthest block, then the UA must first pop all the nodes from the bottom of the * > stack of open elements, from the current node up to and including formatting element, then * > remove formatting element from the list of active formatting elements, and finally return. */ if ( null === $furthest_block ) { foreach ( $this->state->stack_of_open_elements->walk_up() as $item ) { $this->state->stack_of_open_elements->pop(); if ( $formatting_element->bookmark_name === $item->bookmark_name ) { $this->state->active_formatting_elements->remove_node( $formatting_element ); return; } } } $this->last_error = self::ERROR_UNSUPPORTED; throw new WP_HTML_Unsupported_Exception( 'Cannot extract common ancestor in adoption agency algorithm.' ); } $this->last_error = self::ERROR_UNSUPPORTED; throw new WP_HTML_Unsupported_Exception( 'Cannot run adoption agency when looping required.' ); } /** * Inserts an HTML element on the stack of open elements. * * @since 6.4.0 * * @see https://html.spec.whatwg.org/#insert-a-foreign-element * * @param WP_HTML_Token $token Name of bookmark pointing to element in original input HTML. */ private function insert_html_element( $token ) { $this->state->stack_of_open_elements->push( $token ); } /* * HTML Specification Helpers */ /** * Returns whether an element of a given name is in the HTML special category. * * @since 6.4.0 * * @see https://html.spec.whatwg.org/#special * * @param string $tag_name Name of element to check. * @return bool Whether the element of the given name is in the special category. */ public static function is_special( $tag_name ) { $tag_name = strtoupper( $tag_name ); return ( 'ADDRESS' === $tag_name || 'APPLET' === $tag_name || 'AREA' === $tag_name || 'ARTICLE' === $tag_name || 'ASIDE' === $tag_name || 'BASE' === $tag_name || 'BASEFONT' === $tag_name || 'BGSOUND' === $tag_name || 'BLOCKQUOTE' === $tag_name || 'BODY' === $tag_name || 'BR' === $tag_name || 'BUTTON' === $tag_name || 'CAPTION' === $tag_name || 'CENTER' === $tag_name || 'COL' === $tag_name || 'COLGROUP' === $tag_name || 'DD' === $tag_name || 'DETAILS' === $tag_name || 'DIR' === $tag_name || 'DIV' === $tag_name || 'DL' === $tag_name || 'DT' === $tag_name || 'EMBED' === $tag_name || 'FIELDSET' === $tag_name || 'FIGCAPTION' === $tag_name || 'FIGURE' === $tag_name || 'FOOTER' === $tag_name || 'FORM' === $tag_name || 'FRAME' === $tag_name || 'FRAMESET' === $tag_name || 'H1' === $tag_name || 'H2' === $tag_name || 'H3' === $tag_name || 'H4' === $tag_name || 'H5' === $tag_name || 'H6' === $tag_name || 'HEAD' === $tag_name || 'HEADER' === $tag_name || 'HGROUP' === $tag_name || 'HR' === $tag_name || 'HTML' === $tag_name || 'IFRAME' === $tag_name || 'IMG' === $tag_name || 'INPUT' === $tag_name || 'KEYGEN' === $tag_name || 'LI' === $tag_name || 'LINK' === $tag_name || 'LISTING' === $tag_name || 'MAIN' === $tag_name || 'MARQUEE' === $tag_name || 'MENU' === $tag_name || 'META' === $tag_name || 'NAV' === $tag_name || 'NOEMBED' === $tag_name || 'NOFRAMES' === $tag_name || 'NOSCRIPT' === $tag_name || 'OBJECT' === $tag_name || 'OL' === $tag_name || 'P' === $tag_name || 'PARAM' === $tag_name || 'PLAINTEXT' === $tag_name || 'PRE' === $tag_name || 'SCRIPT' === $tag_name || 'SEARCH' === $tag_name || 'SECTION' === $tag_name || 'SELECT' === $tag_name || 'SOURCE' === $tag_name || 'STYLE' === $tag_name || 'SUMMARY' === $tag_name || 'TABLE' === $tag_name || 'TBODY' === $tag_name || 'TD' === $tag_name || 'TEMPLATE' === $tag_name || 'TEXTAREA' === $tag_name || 'TFOOT' === $tag_name || 'TH' === $tag_name || 'THEAD' === $tag_name || 'TITLE' === $tag_name || 'TR' === $tag_name || 'TRACK' === $tag_name || 'UL' === $tag_name || 'WBR' === $tag_name || 'XMP' === $tag_name || // MathML. 'MI' === $tag_name || 'MO' === $tag_name || 'MN' === $tag_name || 'MS' === $tag_name || 'MTEXT' === $tag_name || 'ANNOTATION-XML' === $tag_name || // SVG. 'FOREIGNOBJECT' === $tag_name || 'DESC' === $tag_name || 'TITLE' === $tag_name ); } /** * Returns whether a given element is an HTML Void Element * * > area, base, br, col, embed, hr, img, input, link, meta, source, track, wbr * * @since 6.4.0 * * @see https://html.spec.whatwg.org/#void-elements * * @param string $tag_name Name of HTML tag to check. * @return bool Whether the given tag is an HTML Void Element. */ public static function is_void( $tag_name ) { $tag_name = strtoupper( $tag_name ); return ( 'AREA' === $tag_name || 'BASE' === $tag_name || 'BASEFONT' === $tag_name || // Obsolete but still treated as void. 'BGSOUND' === $tag_name || // Obsolete but still treated as void. 'BR' === $tag_name || 'COL' === $tag_name || 'EMBED' === $tag_name || 'FRAME' === $tag_name || 'HR' === $tag_name || 'IMG' === $tag_name || 'INPUT' === $tag_name || 'KEYGEN' === $tag_name || // Obsolete but still treated as void. 'LINK' === $tag_name || 'META' === $tag_name || 'PARAM' === $tag_name || // Obsolete but still treated as void. 'SOURCE' === $tag_name || 'TRACK' === $tag_name || 'WBR' === $tag_name ); } /* * Constants that would pollute the top of the class if they were found there. */ /** * Indicates that the next HTML token should be parsed and processed. * * @since 6.4.0 * * @var string */ const PROCESS_NEXT_NODE = 'process-next-node'; /** * Indicates that the current HTML token should be reprocessed in the newly-selected insertion mode. * * @since 6.4.0 * * @var string */ const REPROCESS_CURRENT_NODE = 'reprocess-current-node'; /** * Indicates that the current HTML token should be processed without advancing the parser. * * @since 6.5.0 * * @var string */ const PROCESS_CURRENT_NODE = 'process-current-node'; /** * Indicates that the parser encountered unsupported markup and has bailed. * * @since 6.4.0 * * @var string */ const ERROR_UNSUPPORTED = 'unsupported'; /** * Indicates that the parser encountered more HTML tokens than it * was able to process and has bailed. * * @since 6.4.0 * * @var string */ const ERROR_EXCEEDED_MAX_BOOKMARKS = 'exceeded-max-bookmarks'; /** * Unlock code that must be passed into the constructor to create this class. * * This class extends the WP_HTML_Tag_Processor, which has a public class * constructor. Therefore, it's not possible to have a private constructor here. * * This unlock code is used to ensure that anyone calling the constructor is * doing so with a full understanding that it's intended to be a private API. * * @access private */ const CONSTRUCTOR_UNLOCK_CODE = 'Use WP_HTML_Processor::create_fragment() instead of calling the class constructor directly.'; }