Build: Restore block parser in Core.

The work in [61438] for Core-64393 removed the block parser classes from Core, which caused numerous scripts to fail because they were missing. Conditional checks were added in [61492] which left WordPress in an inoperable state.

This patch restores the block parser in Core, in preparation for work to remove it from Gutenberg (in a separate patch).

Ironically, the files were removed because the new build was copying them over from Gutenberg and the intent was to avoid having two sources of truth, but this was previously the existing mechanism, so having done nothing to the parser files would have left the status quo. This patch removes the problems originally created by removing the files. They will not be copied from Gutenberg any more and the only source of truth will be Core.

Until removed from Gutenberg, because of the build changes, any changes made on the Gutenberg side will be lost unless manually copied over.

Developed in: WordPress#10761
Discussed in: https://core.trac.wordpress.org/ticket/64521

Follow-up to [61438], [61492].

Props dmsnell, mcsf, mukesh27, youknowriad.
Fixes #64521.


git-svn-id: https://develop.svn.wordpress.org/trunk@61504 602fd350-edb4-49c9-b593-d223f7449a82

Author: dmsnell

.gitignore

@@ -38,9 +38,6 @@ wp-tests-config.php
 /src/wp-includes/blocks/*
 !/src/wp-includes/blocks/index.php
 /src/wp-includes/build
-/src/wp-includes/class-wp-block-parser.php
-/src/wp-includes/class-wp-block-parser-block.php
-/src/wp-includes/class-wp-block-parser-frame.php
 /src/wp-includes/theme.json
 /packagehash.txt
 /.gutenberg-hash

src/wp-includes/blocks.php

@@ -2421,10 +2421,6 @@ function parse_blocks( $content ) {
 	 */
 	$parser_class = apply_filters( 'block_parser_class', 'WP_Block_Parser' );
 
-	if ( ! class_exists( $parser_class ) ) {
-		return array();
-	}
-
 	$parser = new $parser_class();
 	return $parser->parse( $content );
 }

src/wp-includes/class-wp-block-parser-block.php

@@ -0,0 +1,90 @@
+<?php
+/**
+ * Block Serialization Parser
+ *
+ * @package WordPress
+ */
+
+/**
+ * Class WP_Block_Parser_Block
+ *
+ * Holds the block structure in memory
+ *
+ * @since 5.0.0
+ */
+class WP_Block_Parser_Block {
+	/**
+	 * Name of block
+	 *
+	 * @example "core/paragraph"
+	 *
+	 * @since 5.0.0
+	 * @var string
+	 */
+	public $blockName; // phpcs:ignore WordPress.NamingConventions.ValidVariableName
+
+	/**
+	 * Optional set of attributes from block comment delimiters
+	 *
+	 * @example null
+	 * @example array( 'columns' => 3 )
+	 *
+	 * @since 5.0.0
+	 * @var array|null
+	 */
+	public $attrs;
+
+	/**
+	 * List of inner blocks (of this same class)
+	 *
+	 * @since 5.0.0
+	 * @var WP_Block_Parser_Block[]
+	 */
+	public $innerBlocks; // phpcs:ignore WordPress.NamingConventions.ValidVariableName
+
+	/**
+	 * Resultant HTML from inside block comment delimiters
+	 * after removing inner blocks
+	 *
+	 * @example "...Just <!-- wp:test /--> testing..." -> "Just testing..."
+	 *
+	 * @since 5.0.0
+	 * @var string
+	 */
+	public $innerHTML; // phpcs:ignore WordPress.NamingConventions.ValidVariableName
+
+	/**
+	 * List of string fragments and null markers where inner blocks were found
+	 *
+	 * @example array(
+	 *   'innerHTML'    => 'BeforeInnerAfter',
+	 *   'innerBlocks'  => array( block, block ),
+	 *   'innerContent' => array( 'Before', null, 'Inner', null, 'After' ),
+	 * )
+	 *
+	 * @since 5.0.0
+	 * @var array
+	 */
+	public $innerContent; // phpcs:ignore WordPress.NamingConventions.ValidVariableName
+
+	/**
+	 * Constructor.
+	 *
+	 * Will populate object properties from the provided arguments.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param string $name          Name of block.
+	 * @param array  $attrs         Optional set of attributes from block comment delimiters.
+	 * @param array  $inner_blocks  List of inner blocks (of this same class).
+	 * @param string $inner_html    Resultant HTML from inside block comment delimiters after removing inner blocks.
+	 * @param array  $inner_content List of string fragments and null markers where inner blocks were found.
+	 */
+	public function __construct( $name, $attrs, $inner_blocks, $inner_html, $inner_content ) {
+		$this->blockName    = $name;          // phpcs:ignore WordPress.NamingConventions.ValidVariableName
+		$this->attrs        = $attrs;
+		$this->innerBlocks  = $inner_blocks;  // phpcs:ignore WordPress.NamingConventions.ValidVariableName
+		$this->innerHTML    = $inner_html;    // phpcs:ignore WordPress.NamingConventions.ValidVariableName
+		$this->innerContent = $inner_content; // phpcs:ignore WordPress.NamingConventions.ValidVariableName
+	}
+}

src/wp-includes/class-wp-block-parser-frame.php

@@ -0,0 +1,79 @@
+<?php
+/**
+ * Block Serialization Parser
+ *
+ * @package WordPress
+ */
+
+/**
+ * Class WP_Block_Parser_Frame
+ *
+ * Holds partial blocks in memory while parsing
+ *
+ * @internal
+ * @since 5.0.0
+ */
+class WP_Block_Parser_Frame {
+	/**
+	 * Full or partial block
+	 *
+	 * @since 5.0.0
+	 * @var WP_Block_Parser_Block
+	 */
+	public $block;
+
+	/**
+	 * Byte offset into document for start of parse token
+	 *
+	 * @since 5.0.0
+	 * @var int
+	 */
+	public $token_start;
+
+	/**
+	 * Byte length of entire parse token string
+	 *
+	 * @since 5.0.0
+	 * @var int
+	 */
+	public $token_length;
+
+	/**
+	 * Byte offset into document for after parse token ends
+	 * (used during reconstruction of stack into parse production)
+	 *
+	 * @since 5.0.0
+	 * @var int
+	 */
+	public $prev_offset;
+
+	/**
+	 * Byte offset into document where leading HTML before token starts
+	 *
+	 * @since 5.0.0
+	 * @var int
+	 */
+	public $leading_html_start;
+
+	/**
+	 * Constructor
+	 *
+	 * Will populate object properties from the provided arguments.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param WP_Block_Parser_Block $block              Full or partial block.
+	 * @param int                   $token_start        Byte offset into document for start of parse token.
+	 * @param int                   $token_length       Byte length of entire parse token string.
+	 * @param int|null              $prev_offset        Optional. Byte offset into document for after parse token ends. Default null.
+	 * @param int|null              $leading_html_start Optional. Byte offset into document where leading HTML before token starts.
+	 *                                                  Default null.
+	 */
+	public function __construct( $block, $token_start, $token_length, $prev_offset = null, $leading_html_start = null ) {
+		$this->block              = $block;
+		$this->token_start        = $token_start;
+		$this->token_length       = $token_length;
+		$this->prev_offset        = isset( $prev_offset ) ? $prev_offset : $token_start + $token_length;
+		$this->leading_html_start = $leading_html_start;
+	}
+}