HTML API: Add TEMPLATE and related support in HTML Processor.

As part of work to add more spec support to the HTML API, this patch adds
support for the IN TEMPLATE and IN HEAD insertion modes. These changes are
primarily about adding support for TEMPLATE elements in the HTML Processor,
but include support for other tags commonly found in the document head, such
as LINK, META, SCRIPT, STYLE, and TITLE.

Developed in https://github.com/wordpress/wordpress-develop/pull/7046
Discussed in https://core.trac.wordpress.org/ticket/61576

Props: dmsnell, jonsurrell, westonruter.
See #61576.

Built from https://develop.svn.wordpress.org/trunk@58833


git-svn-id: http://core.svn.wordpress.org/trunk@58229 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/html-api/class-wp-html-open-elements.php

@@ -308,7 +308,20 @@ class WP_HTML_Open_Elements {
 				'MARQUEE',
 				'OBJECT',
 				'TEMPLATE',
-				// @todo: Support SVG and MathML nodes when support for foreign content is added.
+
+				/*
+				 * @todo Support SVG and MathML nodes when support for foreign content is added.
+				 *
+				 * - MathML mi
+				 * - MathML mo
+				 * - MathML mn
+				 * - MathML ms
+				 * - MathML mtext
+				 * - MathML annotation-xml
+				 * - SVG foreignObject
+				 * - SVG desc
+				 * - SVG title
+				 */
 			)
 		);
 	}
@@ -349,7 +362,20 @@ class WP_HTML_Open_Elements {
 				'OL',
 				'TEMPLATE',
 				'UL',
-				// @todo: Support SVG and MathML nodes when support for foreign content is added.
+
+				/*
+				 * @todo Support SVG and MathML nodes when support for foreign content is added.
+				 *
+				 * - MathML mi
+				 * - MathML mo
+				 * - MathML mn
+				 * - MathML ms
+				 * - MathML mtext
+				 * - MathML annotation-xml
+				 * - SVG foreignObject
+				 * - SVG desc
+				 * - SVG title
+				 */
 			)
 		);
 	}
@@ -386,7 +412,20 @@ class WP_HTML_Open_Elements {
 				'MARQUEE',
 				'OBJECT',
 				'TEMPLATE',
-				// @todo: Support SVG and MathML nodes when support for foreign content is added.
+
+				/*
+				 * @todo Support SVG and MathML nodes when support for foreign content is added.
+				 *
+				 * - MathML mi
+				 * - MathML mo
+				 * - MathML mn
+				 * - MathML ms
+				 * - MathML mtext
+				 * - MathML annotation-xml
+				 * - SVG foreignObject
+				 * - SVG desc
+				 * - SVG title
+				 */
 			)
 		);
 	}

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

@@ -1040,7 +1040,7 @@ class WP_HTML_Processor extends WP_HTML_Tag_Processor {
 	 * This internal function performs the 'in head' insertion mode
 	 * logic for the generalized WP_HTML_Processor::step() function.
 	 *
-	 * @since 6.7.0 Stub implementation.
+	 * @since 6.7.0
 	 *
 	 * @throws WP_HTML_Unsupported_Exception When encountering unsupported HTML input.
 	 *
@@ -1050,7 +1050,211 @@ class WP_HTML_Processor extends WP_HTML_Tag_Processor {
 	 * @return bool Whether an element was found.
 	 */
 	private function step_in_head(): bool {
-		$this->bail( 'No support for parsing in the ' . WP_HTML_Processor_State::INSERTION_MODE_IN_HEAD . ' state.' );
+		$token_name = $this->get_token_name();
+		$token_type = $this->get_token_type();
+		$is_closer  = parent::is_tag_closer();
+		$op_sigil   = '#tag' === $token_type ? ( $is_closer ? '-' : '+' ) : '';
+		$op         = "{$op_sigil}{$token_name}";
+
+		/*
+		 * > A character token that is one of U+0009 CHARACTER TABULATION,
+		 * > U+000A LINE FEED (LF), U+000C FORM FEED (FF),
+		 * > U+000D CARRIAGE RETURN (CR), or U+0020 SPACE
+		 */
+		if ( '#text' === $op ) {
+			$text = $this->get_modifiable_text();
+			if ( '' === $text ) {
+				/*
+				 * If the text is empty after processing HTML entities and stripping
+				 * U+0000 NULL bytes then ignore the token.
+				 */
+				return $this->step();
+			}
+
+			if ( strlen( $text ) === strspn( $text, " \t\n\f\r" ) ) {
+				// Insert the character.
+				$this->insert_html_element( $this->state->current_token );
+				return true;
+			}
+		}
+
+		switch ( $op ) {
+			/*
+			 * > A comment token
+			 */
+			case '#comment':
+			case '#funky-comment':
+			case '#presumptuous-tag':
+				$this->insert_html_element( $this->state->current_token );
+				return true;
+
+			/*
+			 * > A DOCTYPE token
+			 */
+			case 'html':
+				// Parse error: ignore the token.
+				return $this->step();
+
+			/*
+			 * > A start tag whose tag name is "html"
+			 */
+			case '+HTML':
+				return $this->step_in_body();
+
+			/*
+			 * > A start tag whose tag name is one of: "base", "basefont", "bgsound", "link"
+			 */
+			case '+BASE':
+			case '+BASEFONT':
+			case '+BGSOUND':
+			case '+LINK':
+				$this->insert_html_element( $this->state->current_token );
+				return true;
+
+			/*
+			 * > A start tag whose tag name is "meta"
+			 */
+			case '+META':
+				$this->insert_html_element( $this->state->current_token );
+
+				/*
+				 * > If the active speculative HTML parser is null, then:
+				 * >   - If the element has a charset attribute, and getting an encoding from
+				 * >     its value results in an encoding, and the confidence is currently
+				 * >     tentative, then change the encoding to the resulting encoding.
+				 */
+				$charset = $this->get_attribute( 'charset' );
+				if ( is_string( $charset ) ) {
+					$this->bail( 'Cannot yet process META tags with charset to determine encoding.' );
+				}
+
+				/*
+				 * >   - Otherwise, if the element has an http-equiv attribute whose value is
+				 * >     an ASCII case-insensitive match for the string "Content-Type", and
+				 * >     the element has a content attribute, and applying the algorithm for
+				 * >     extracting a character encoding from a meta element to that attribute's
+				 * >     value returns an encoding, and the confidence is currently tentative,
+				 * >     then change the encoding to the extracted encoding.
+				 */
+				$http_equiv = $this->get_attribute( 'http-equiv' );
+				$content    = $this->get_attribute( 'content' );
+				if (
+					is_string( $http_equiv ) &&
+					is_string( $content ) &&
+					0 === strcasecmp( $http_equiv, 'Content-Type' )
+				) {
+					$this->bail( 'Cannot yet process META tags with http-equiv Content-Type to determine encoding.' );
+				}
+
+				return true;
+
+			/*
+			 * > A start tag whose tag name is "title"
+			 */
+			case '+TITLE':
+				$this->insert_html_element( $this->state->current_token );
+				return true;
+
+			/*
+			 * > A start tag whose tag name is "noscript", if the scripting flag is enabled
+			 * > A start tag whose tag name is one of: "noframes", "style"
+			 *
+			 * The scripting flag is never enabled in this parser.
+			 */
+			case '+NOFRAMES':
+			case '+STYLE':
+				$this->insert_html_element( $this->state->current_token );
+				return true;
+
+			/*
+			 * > A start tag whose tag name is "noscript", if the scripting flag is disabled
+			 */
+			case '+NOSCRIPT':
+				$this->insert_html_element( $this->state->current_token );
+				$this->state->insertion_mode = WP_HTML_Processor_State::INSERTION_MODE_IN_HEAD_NOSCRIPT;
+				return true;
+
+			/*
+			 * > A start tag whose tag name is "script"
+			 *
+			 * @todo Could the adjusted insertion location be anything other than the current location?
+			 */
+			case '+SCRIPT':
+				$this->insert_html_element( $this->state->current_token );
+				return true;
+
+			/*
+			 * > An end tag whose tag name is "head"
+			 */
+			case '-HEAD':
+				$this->state->stack_of_open_elements->pop();
+				$this->state->insertion_mode = WP_HTML_Processor_State::INSERTION_MODE_AFTER_HEAD;
+				return true;
+
+			/*
+			 * > An end tag whose tag name is one of: "body", "html", "br"
+			 */
+			case '-BODY':
+			case '-HTML':
+			case '-BR':
+				/*
+				 * > Act as described in the "anything else" entry below.
+				 */
+				goto in_head_anything_else;
+				break;
+
+			/*
+			 * > A start tag whose tag name is "template"
+			 *
+			 * @todo Could the adjusted insertion location be anything other than the current location?
+			 */
+			case '+TEMPLATE':
+				$this->state->active_formatting_elements->insert_marker();
+				$this->state->frameset_ok = false;
+
+				$this->state->insertion_mode                      = WP_HTML_Processor_State::INSERTION_MODE_IN_TEMPLATE;
+				$this->state->stack_of_template_insertion_modes[] = WP_HTML_Processor_State::INSERTION_MODE_IN_TEMPLATE;
+
+				$this->insert_html_element( $this->state->current_token );
+				return true;
+
+			/*
+			 * > An end tag whose tag name is "template"
+			 */
+			case '-TEMPLATE':
+				if ( ! $this->state->stack_of_open_elements->contains( 'TEMPLATE' ) ) {
+					// @todo Indicate a parse error once it's possible.
+					return $this->step();
+				}
+
+				$this->generate_implied_end_tags_thoroughly();
+				if ( ! $this->state->stack_of_open_elements->current_node_is( 'TEMPLATE' ) ) {
+					// @todo Indicate a parse error once it's possible.
+				}
+
+				$this->state->stack_of_open_elements->pop_until( 'TEMPLATE' );
+				$this->state->active_formatting_elements->clear_up_to_last_marker();
+				array_pop( $this->state->stack_of_template_insertion_modes );
+				$this->reset_insertion_mode();
+				return true;
+		}
+
+		/*
+		 * > A start tag whose tag name is "head"
+		 * > Any other end tag
+		 */
+		if ( '+HEAD' === $op || $is_closer ) {
+			// Parse error: ignore the token.
+			return $this->step();
+		}
+
+		/*
+		 * > Anything else
+		 */
+		in_head_anything_else:
+		$this->state->stack_of_open_elements->pop();
+		$this->state->insertion_mode = WP_HTML_Processor_State::INSERTION_MODE_AFTER_HEAD;
+		return $this->step( self::REPROCESS_CURRENT_NODE );
 	}
 
 	/**
@@ -2991,7 +3195,117 @@ class WP_HTML_Processor extends WP_HTML_Tag_Processor {
 	 * @return bool Whether an element was found.
 	 */
 	private function step_in_template(): bool {
-		$this->bail( 'No support for parsing in the ' . WP_HTML_Processor_State::INSERTION_MODE_IN_TEMPLATE . ' state.' );
+		$token_name = $this->get_token_name();
+		$token_type = $this->get_token_type();
+		$is_closer  = $this->is_tag_closer();
+		$op_sigil   = '#tag' === $token_type ? ( $is_closer ? '-' : '+' ) : '';
+		$op         = "{$op_sigil}{$token_name}";
+
+		switch ( $op ) {
+			/*
+			 * > A character token
+			 * > A comment token
+			 * > A DOCTYPE token
+			 */
+			case '#text':
+			case '#comment':
+			case '#funky-comment':
+			case '#presumptuous-tag':
+			case 'html':
+				return $this->step_in_body();
+
+			/*
+			 * > A start tag whose tag name is one of: "base", "basefont", "bgsound", "link",
+			 * > "meta", "noframes", "script", "style", "template", "title"
+			 * > An end tag whose tag name is "template"
+			 */
+			case '+BASE':
+			case '+BASEFONT':
+			case '+BGSOUND':
+			case '+LINK':
+			case '+META':
+			case '+NOFRAMES':
+			case '+SCRIPT':
+			case '+STYLE':
+			case '+TEMPLATE':
+			case '+TITLE':
+			case '-TEMPLATE':
+				return $this->step_in_head();
+
+			/*
+			 * > A start tag whose tag name is one of: "caption", "colgroup", "tbody", "tfoot", "thead"
+			 */
+			case '+CAPTION':
+			case '+COLGROUP':
+			case '+TBODY':
+			case '+TFOOT':
+			case '+THEAD':
+				array_pop( $this->state->stack_of_template_insertion_modes );
+				$this->state->stack_of_template_insertion_modes[] = WP_HTML_Processor_State::INSERTION_MODE_IN_TABLE;
+				$this->state->insertion_mode                      = WP_HTML_Processor_State::INSERTION_MODE_IN_TABLE;
+				return $this->step( self::REPROCESS_CURRENT_NODE );
+
+			/*
+			 * > A start tag whose tag name is "col"
+			 */
+			case '+COL':
+				array_pop( $this->state->stack_of_template_insertion_modes );
+				$this->state->stack_of_template_insertion_modes[] = WP_HTML_Processor_State::INSERTION_MODE_IN_COLUMN_GROUP;
+				$this->state->insertion_mode                      = WP_HTML_Processor_State::INSERTION_MODE_IN_COLUMN_GROUP;
+				return $this->step( self::REPROCESS_CURRENT_NODE );
+
+			/*
+			 * > A start tag whose tag name is "tr"
+			 */
+			case '+TR':
+				array_pop( $this->state->stack_of_template_insertion_modes );
+				$this->state->stack_of_template_insertion_modes[] = WP_HTML_Processor_State::INSERTION_MODE_IN_TABLE_BODY;
+				$this->state->insertion_mode                      = WP_HTML_Processor_State::INSERTION_MODE_IN_TABLE_BODY;
+				return $this->step( self::REPROCESS_CURRENT_NODE );
+
+			/*
+			 * > A start tag whose tag name is one of: "td", "th"
+			 */
+			case '+TD':
+			case '+TH':
+				array_pop( $this->state->stack_of_template_insertion_modes );
+				$this->state->stack_of_template_insertion_modes[] = WP_HTML_Processor_State::INSERTION_MODE_IN_ROW;
+				$this->state->insertion_mode                      = WP_HTML_Processor_State::INSERTION_MODE_IN_ROW;
+				return $this->step( self::REPROCESS_CURRENT_NODE );
+		}
+
+		/*
+		 * > Any other start tag
+		 */
+		if ( ! $is_closer ) {
+			array_pop( $this->state->stack_of_template_insertion_modes );
+			$this->state->stack_of_template_insertion_modes[] = WP_HTML_Processor_State::INSERTION_MODE_IN_BODY;
+			$this->state->insertion_mode                      = WP_HTML_Processor_State::INSERTION_MODE_IN_BODY;
+			return $this->step( self::REPROCESS_CURRENT_NODE );
+		}
+
+		/*
+		 * > Any other end tag
+		 */
+		if ( $is_closer ) {
+			// Parse error: ignore the token.
+			return $this->step();
+		}
+
+		/*
+		 * > An end-of-file token
+		 */
+		if ( ! $this->state->stack_of_open_elements->contains( 'TEMPLATE' ) ) {
+			// Stop parsing.
+			return false;
+		}
+
+		// @todo Indicate a parse error once it's possible.
+		$this->state->stack_of_open_elements->pop_until( 'TEMPLATE' );
+		$this->state->active_formatting_elements->clear_up_to_last_marker();
+		array_pop( $this->state->stack_of_template_insertion_modes );
+		$this->reset_insertion_mode();
+		return $this->step( self::REPROCESS_CURRENT_NODE );
 	}
 
 	/**

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.7-alpha-58832';
+$wp_version = '6.7-alpha-58833';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.