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Edit File: class-wp-block-parser.php
<?php /** * Block Serialization Parser * * @package WordPress */ /** * Class WP_Block_Parser * * Parses a document and constructs a list of parsed block objects * * @since 5.0.0 * @since 4.0.0 returns arrays not objects, all attributes are arrays */ class WP_Block_Parser { /** * Input document being parsed * * @example "Pre-text\n<!-- wp:paragraph -->This is inside a block!<!-- /wp:paragraph -->" * * @since 5.0.0 * @var string */ public $document; /** * Tracks parsing progress through document * * @since 5.0.0 * @var int */ public $offset; /** * List of parsed blocks * * @since 5.0.0 * @var array[] */ public $output; /** * Stack of partially-parsed structures in memory during parse * * @since 5.0.0 * @var WP_Block_Parser_Frame[] */ public $stack; /** * Parses a document and returns a list of block structures * * When encountering an invalid parse will return a best-effort * parse. In contrast to the specification parser this does not * return an error on invalid inputs. * * @since 5.0.0 * * @param string $document Input document being parsed. * @return array[] */ public function parse( $document ) { $this->document = $document; $this->offset = 0; $this->output = array(); $this->stack = array(); while ( $this->proceed() ) { continue; } return $this->output; } /** * Processes the next token from the input document * and returns whether to proceed eating more tokens * * This is the "next step" function that essentially * takes a token as its input and decides what to do * with that token before descending deeper into a * nested block tree or continuing along the document * or breaking out of a level of nesting. * * @internal * @since 5.0.0 * @return bool */ public function proceed() { $next_token = $this->next_token(); list( $token_type, $block_name, $attrs, $start_offset, $token_length ) = $next_token; $stack_depth = count( $this->stack ); // we may have some HTML soup before the next block. $leading_html_start = $start_offset > $this->offset ? $this->offset : null; switch ( $token_type ) { case 'no-more-tokens': // if not in a block then flush output. if ( 0 === $stack_depth ) { $this->add_freeform(); return false; } /* * Otherwise we have a problem * This is an error * * we have options * - treat it all as freeform text * - assume an implicit closer (easiest when not nesting) */ // for the easy case we'll assume an implicit closer. if ( 1 === $stack_depth ) { $this->add_block_from_stack(); return false; } /* * for the nested case where it's more difficult we'll * have to assume that multiple closers are missing * and so we'll collapse the whole stack piecewise */ while ( 0 < count( $this->stack ) ) { $this->add_block_from_stack(); } return false; case 'void-block': /* * easy case is if we stumbled upon a void block * in the top-level of the document */ if ( 0 === $stack_depth ) { if ( isset( $leading_html_start ) ) { $this->output[] = (array) $this->freeform( substr( $this->document, $leading_html_start, $start_offset - $leading_html_start ) ); } $this->output[] = (array) new WP_Block_Parser_Block( $block_name, $attrs, array(), '', array() ); $this->offset = $start_offset + $token_length; return true; } // otherwise we found an inner block. $this->add_inner_block( new WP_Block_Parser_Block( $block_name, $attrs, array(), '', array() ), $start_offset, $token_length ); $this->offset = $start_offset + $token_length; return true; case 'block-opener': // track all newly-opened blocks on the stack. array_push( $this->stack, new WP_Block_Parser_Frame( new WP_Block_Parser_Block( $block_name, $attrs, array(), '', array() ), $start_offset, $token_length, $start_offset + $token_length, $leading_html_start ) ); $this->offset = $start_offset + $token_length; return true; case 'block-closer': /* * if we're missing an opener we're in trouble * This is an error */ if ( 0 === $stack_depth ) { /* * we have options * - assume an implicit opener * - assume _this_ is the opener * - give up and close out the document */ $this->add_freeform(); return false; } // if we're not nesting then this is easy - close the block. if ( 1 === $stack_depth ) { $this->add_block_from_stack( $start_offset ); $this->offset = $start_offset + $token_length; return true; } /* * otherwise we're nested and we have to close out the current * block and add it as a new innerBlock to the parent */ $stack_top = array_pop( $this->stack ); $html = substr( $this->document, $stack_top->prev_offset, $start_offset - $stack_top->prev_offset ); $stack_top->block->innerHTML .= $html; $stack_top->block->innerContent[] = $html; $stack_top->prev_offset = $start_offset + $token_length; $this->add_inner_block( $stack_top->block, $stack_top->token_start, $stack_top->token_length, $start_offset + $token_length ); $this->offset = $start_offset + $token_length; return true; default: // This is an error. $this->add_freeform(); return false; } } /** * Scans the document from where we last left off * and finds the next valid token to parse if it exists * * Returns the type of the find: kind of find, block information, attributes * * @internal * @since 5.0.0 * @since 4.6.1 fixed a bug in attribute parsing which caused catastrophic backtracking on invalid block comments * @return array */ public function next_token() { $matches = null; /* * aye the magic * we're using a single RegExp to tokenize the block comment delimiters * we're also using a trick here because the only difference between a * block opener and a block closer is the leading `/` before `wp:` (and * a closer has no attributes). we can trap them both and process the * match back in PHP to see which one it was. */ $has_match = preg_match( '/<!--\s+(?P<closer>\/)?wp:(?P<namespace>[a-z][a-z0-9_-]*\/)?(?P<name>[a-z][a-z0-9_-]*)\s+(?P<attrs>{(?:(?:[^}]+|}+(?=})|(?!}\s+\/?-->).)*+)?}\s+)?(?P<void>\/)?-->/s', $this->document, $matches, PREG_OFFSET_CAPTURE, $this->offset ); // if we get here we probably have catastrophic backtracking or out-of-memory in the PCRE. if ( false === $has_match ) { return array( 'no-more-tokens', null, null, null, null ); } // we have no more tokens. if ( 0 === $has_match ) { return array( 'no-more-tokens', null, null, null, null ); } list( $match, $started_at ) = $matches[0]; $length = strlen( $match ); $is_closer = isset( $matches['closer'] ) && -1 !== $matches['closer'][1]; $is_void = isset( $matches['void'] ) && -1 !== $matches['void'][1]; $namespace = $matches['namespace']; $namespace = ( isset( $namespace ) && -1 !== $namespace[1] ) ? $namespace[0] : 'core/'; $name = $namespace . $matches['name'][0]; $has_attrs = isset( $matches['attrs'] ) && -1 !== $matches['attrs'][1]; /* * Fun fact! It's not trivial in PHP to create "an empty associative array" since all arrays * are associative arrays. If we use `array()` we get a JSON `[]` */ $attrs = $has_attrs ? json_decode( $matches['attrs'][0], /* as-associative */ true ) : array(); /* * This state isn't allowed * This is an error */ if ( $is_closer && ( $is_void || $has_attrs ) ) { // we can ignore them since they don't hurt anything. } if ( $is_void ) { return array( 'void-block', $name, $attrs, $started_at, $length ); } if ( $is_closer ) { return array( 'block-closer', $name, null, $started_at, $length ); } return array( 'block-opener', $name, $attrs, $started_at, $length ); } /** * Returns a new block object for freeform HTML * * @internal * @since 5.0.0 * * @param string $inner_html HTML content of block. * @return WP_Block_Parser_Block freeform block object. */ public function freeform( $inner_html ) { return new WP_Block_Parser_Block( null, array(), array(), $inner_html, array( $inner_html ) ); } /** * Pushes a length of text from the input document * to the output list as a freeform block. * * @internal * @since 5.0.0 * @param null|int $length How many bytes of document text to output. */ public function add_freeform( $length = null ) { $length = $length ? $length : strlen( $this->document ) - $this->offset; if ( 0 === $length ) { return; } $this->output[] = (array) $this->freeform( substr( $this->document, $this->offset, $length ) ); } /** * Given a block structure from memory pushes * a new block to the output list. * * @internal * @since 5.0.0 * @param WP_Block_Parser_Block $block The block to add to the output. * @param int $token_start Byte offset into the document where the first token for the block starts. * @param int $token_length Byte length of entire block from start of opening token to end of closing token. * @param int|null $last_offset Last byte offset into document if continuing form earlier output. */ public function add_inner_block( WP_Block_Parser_Block $block, $token_start, $token_length, $last_offset = null ) { $parent = $this->stack[ array_key_last( $this->stack ) ]; $parent->block->innerBlocks[] = (array) $block; $html = substr( $this->document, $parent->prev_offset, $token_start - $parent->prev_offset ); if ( ! empty( $html ) ) { $parent->block->innerHTML .= $html; $parent->block->innerContent[] = $html; } $parent->block->innerContent[] = null; $parent->prev_offset = $last_offset ? $last_offset : $token_start + $token_length; } /** * Pushes the top block from the parsing stack to the output list. * * @internal * @since 5.0.0 * @param int|null $end_offset byte offset into document for where we should stop sending text output as HTML. */ public function add_block_from_stack( $end_offset = null ) { $stack_top = array_pop( $this->stack ); $prev_offset = $stack_top->prev_offset; $html = isset( $end_offset ) ? substr( $this->document, $prev_offset, $end_offset - $prev_offset ) : substr( $this->document, $prev_offset ); if ( ! empty( $html ) ) { $stack_top->block->innerHTML .= $html; $stack_top->block->innerContent[] = $html; } if ( isset( $stack_top->leading_html_start ) ) { $this->output[] = (array) $this->freeform( substr( $this->document, $stack_top->leading_html_start, $stack_top->token_start - $stack_top->leading_html_start ) ); } $this->output[] = (array) $stack_top->block; } } /** * WP_Block_Parser_Block class. * * Required for backward compatibility in WordPress Core. */ require_once __DIR__ . '/class-wp-block-parser-block.php'; /** * WP_Block_Parser_Frame class. * * Required for backward compatibility in WordPress Core. */ require_once __DIR__ . '/class-wp-block-parser-frame.php';