WordPress/wp-includes/html-api/class-wp-html-processor-state.php

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HTML-API: Introduce minimal HTML Processor. This patch introduces the //first// of //many// iterations on the evolution of the HTML API, the HTML Processor, which is built in order to understand HTML structure including nesting, misnesting, and complicated semantic rules. In the first iteration, the HTML Processor is arbitrarily limited to a minimal subset of functionality so that we can review it, ship it, test it, and collect feedback before moving forward. This means that this patch is more or less an extension to the Tag Processor query language, providing the ability not only to scan for a tag of a given name, but also to find an HTML element in a specific nesting path. The HTML Processor also aborts any time it encounters: - a tag that isn't a `P`, `DIV`, `FIGURE`, `FIGCAPTION`, `IMG`, `STRONG`, `B`, `EM`, `I`, `A`, `BIG`, `CODE`, `FONT`, `SMALL`, `STRIKE`, `TT`, or `U` tag. this limit exists because many HTML elements require specific rules and we are trying to limit the number of rules introduced at once. this work is targeted at existing work in places like the image block. - certain misnesting constructs that evoke complicated resolution inside the HTML spec. where possible and where simple to do reliably, certain parse errors are handled. in most cases the HTML Processor aborts. The structure of the HTML Processor is established in this patch. Further spec-compliance comes through filling out //more of the same// kind and nature of code as is found in this patch. Certain critical HTML algorithms are partially supported, and where support requires more than is present, the HTML Processor acknowledges this and refuses to operate. In this patch are explorations for how to verify that new HTML support is fully added (instead of allowing for partial updates that leave some code paths non-compliant). Performance is hard to measure since support is so limited at the current time, but it should generally follow the performance of the Tag Processor somewhat close as the overhead is minimized as much as practical. Props dmsnell, zieladam, costdev. Fixes #58517. Built from https://develop.svn.wordpress.org/trunk@56274 git-svn-id: http://core.svn.wordpress.org/trunk@55786 1a063a9b-81f0-0310-95a4-ce76da25c4cd
2023-07-20 15:43:25 +02:00
<?php
/**
* HTML API: WP_HTML_Processor_State class
*
* @package WordPress
* @subpackage HTML-API
* @since 6.4.0
*/
/**
* Core class used by the HTML processor during HTML parsing
* for managing the internal parsing state.
*
* This class is designed for internal use by the HTML processor.
*
* @since 6.4.0
*
* @access private
*
* @see WP_HTML_Processor
*/
class WP_HTML_Processor_State {
/*
* Insertion mode constants.
*
* These constants exist and are named to make it easier to
* discover and recognize the supported insertion modes in
* the parser.
*
* Out of all the possible insertion modes, only those
* supported by the parser are listed here. As support
* is added to the parser for more modes, add them here
* following the same naming and value pattern.
*
* @see https://html.spec.whatwg.org/#the-insertion-mode
*/
/**
* Initial insertion mode for full HTML parser.
*
* @since 6.4.0
*
* @see https://html.spec.whatwg.org/#the-initial-insertion-mode
* @see WP_HTML_Processor_State::$insertion_mode
*
* @var string
*/
const INSERTION_MODE_INITIAL = 'insertion-mode-initial';
/**
* In body insertion mode for full HTML parser.
*
* @since 6.4.0
*
* @see https://html.spec.whatwg.org/#parsing-main-inbody
* @see WP_HTML_Processor_State::$insertion_mode
*
* @var string
*/
const INSERTION_MODE_IN_BODY = 'insertion-mode-in-body';
/**
* Tracks open elements while scanning HTML.
*
* This property is initialized in the constructor and never null.
*
* @since 6.4.0
*
* @see https://html.spec.whatwg.org/#stack-of-open-elements
*
* @var WP_HTML_Open_Elements
*/
public $stack_of_open_elements = null;
/**
* Tracks open formatting elements, used to handle mis-nested formatting element tags.
*
* This property is initialized in the constructor and never null.
*
* @since 6.4.0
*
* @see https://html.spec.whatwg.org/#list-of-active-formatting-elements
*
* @var WP_HTML_Active_Formatting_Elements
*/
public $active_formatting_elements = null;
/**
* Refers to the currently-matched tag, if any.
*
* @since 6.4.0
*
* @var WP_HTML_Token|null
*/
public $current_token = null;
HTML-API: Introduce minimal HTML Processor. This patch introduces the //first// of //many// iterations on the evolution of the HTML API, the HTML Processor, which is built in order to understand HTML structure including nesting, misnesting, and complicated semantic rules. In the first iteration, the HTML Processor is arbitrarily limited to a minimal subset of functionality so that we can review it, ship it, test it, and collect feedback before moving forward. This means that this patch is more or less an extension to the Tag Processor query language, providing the ability not only to scan for a tag of a given name, but also to find an HTML element in a specific nesting path. The HTML Processor also aborts any time it encounters: - a tag that isn't a `P`, `DIV`, `FIGURE`, `FIGCAPTION`, `IMG`, `STRONG`, `B`, `EM`, `I`, `A`, `BIG`, `CODE`, `FONT`, `SMALL`, `STRIKE`, `TT`, or `U` tag. this limit exists because many HTML elements require specific rules and we are trying to limit the number of rules introduced at once. this work is targeted at existing work in places like the image block. - certain misnesting constructs that evoke complicated resolution inside the HTML spec. where possible and where simple to do reliably, certain parse errors are handled. in most cases the HTML Processor aborts. The structure of the HTML Processor is established in this patch. Further spec-compliance comes through filling out //more of the same// kind and nature of code as is found in this patch. Certain critical HTML algorithms are partially supported, and where support requires more than is present, the HTML Processor acknowledges this and refuses to operate. In this patch are explorations for how to verify that new HTML support is fully added (instead of allowing for partial updates that leave some code paths non-compliant). Performance is hard to measure since support is so limited at the current time, but it should generally follow the performance of the Tag Processor somewhat close as the overhead is minimized as much as practical. Props dmsnell, zieladam, costdev. Fixes #58517. Built from https://develop.svn.wordpress.org/trunk@56274 git-svn-id: http://core.svn.wordpress.org/trunk@55786 1a063a9b-81f0-0310-95a4-ce76da25c4cd
2023-07-20 15:43:25 +02:00
/**
* Tree construction insertion mode.
*
* @since 6.4.0
*
* @see https://html.spec.whatwg.org/#insertion-mode
*
* @var string
*/
public $insertion_mode = self::INSERTION_MODE_INITIAL;
/**
* Context node initializing fragment parser, if created as a fragment parser.
*
* @since 6.4.0
*
* @see https://html.spec.whatwg.org/#concept-frag-parse-context
*
* @var [string, array]|null
*/
public $context_node = null;
/**
* The frameset-ok flag indicates if a `FRAMESET` element is allowed in the current state.
*
* > The frameset-ok flag is set to "ok" when the parser is created. It is set to "not ok" after certain tokens are seen.
*
* @since 6.4.0
*
* @see https://html.spec.whatwg.org/#frameset-ok-flag
*
* @var bool
*/
public $frameset_ok = true;
HTML-API: Introduce minimal HTML Processor. This patch introduces the //first// of //many// iterations on the evolution of the HTML API, the HTML Processor, which is built in order to understand HTML structure including nesting, misnesting, and complicated semantic rules. In the first iteration, the HTML Processor is arbitrarily limited to a minimal subset of functionality so that we can review it, ship it, test it, and collect feedback before moving forward. This means that this patch is more or less an extension to the Tag Processor query language, providing the ability not only to scan for a tag of a given name, but also to find an HTML element in a specific nesting path. The HTML Processor also aborts any time it encounters: - a tag that isn't a `P`, `DIV`, `FIGURE`, `FIGCAPTION`, `IMG`, `STRONG`, `B`, `EM`, `I`, `A`, `BIG`, `CODE`, `FONT`, `SMALL`, `STRIKE`, `TT`, or `U` tag. this limit exists because many HTML elements require specific rules and we are trying to limit the number of rules introduced at once. this work is targeted at existing work in places like the image block. - certain misnesting constructs that evoke complicated resolution inside the HTML spec. where possible and where simple to do reliably, certain parse errors are handled. in most cases the HTML Processor aborts. The structure of the HTML Processor is established in this patch. Further spec-compliance comes through filling out //more of the same// kind and nature of code as is found in this patch. Certain critical HTML algorithms are partially supported, and where support requires more than is present, the HTML Processor acknowledges this and refuses to operate. In this patch are explorations for how to verify that new HTML support is fully added (instead of allowing for partial updates that leave some code paths non-compliant). Performance is hard to measure since support is so limited at the current time, but it should generally follow the performance of the Tag Processor somewhat close as the overhead is minimized as much as practical. Props dmsnell, zieladam, costdev. Fixes #58517. Built from https://develop.svn.wordpress.org/trunk@56274 git-svn-id: http://core.svn.wordpress.org/trunk@55786 1a063a9b-81f0-0310-95a4-ce76da25c4cd
2023-07-20 15:43:25 +02:00
/**
* Constructor - creates a new and empty state value.
*
* @since 6.4.0
*
* @see WP_HTML_Processor
*/
public function __construct() {
$this->stack_of_open_elements = new WP_HTML_Open_Elements();
$this->active_formatting_elements = new WP_HTML_Active_Formatting_Elements();
}
}