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Diffstat (limited to 'wp-includes/class-wp-block-parser.php')
| -rw-r--r-- | wp-includes/class-wp-block-parser.php | 404 |
1 files changed, 404 insertions, 0 deletions
diff --git a/wp-includes/class-wp-block-parser.php b/wp-includes/class-wp-block-parser.php new file mode 100644 index 0000000..543f536 --- /dev/null +++ b/wp-includes/class-wp-block-parser.php @@ -0,0 +1,404 @@ +<?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 WP_Block_Parser_Block[] + */ + 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 3.9.0 + * + * @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 $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[ count( $this->stack ) - 1 ]; + $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'; |