Block Processor: Normalize the searched block type once.

`next_delimiter( $block_type )` called `is_block_type()` for every
delimiter, which calls `are_equal_block_types()`. That scans both block
types for `/` and builds a `core/` string whenever exactly one of them
has a namespace.

Normalize the searched block type once per call. A delimiter whose
block type has no namespace then matches only the part after `core/`,
and every other delimiter matches the full type. Both comparisons check
the length first.

`next_block( $block_type )` takes 13% to 21% less time.

Adds explicit namespaces and search types which cannot match to the
test comparing `next_delimiter()` with `next_token()`.

See #66138.

Author: sirreal

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

@@ -678,9 +678,31 @@ public function next_delimiter( ?string $block_name = null ): bool {
 		if ( ! isset( $block_name ) ) {
 			$found = $this->next_token();
 		} else {
+			// A block type in the document without a namespace is in the implicit `core` namespace.
+			$text       = $this->source_text;
+			$block_type = self::normalize_block_type( $block_name );
+			$core_name  = str_starts_with( $block_type, 'core/' ) ? substr( $block_type, 5 ) : null;
+
 			do {
 				$found = $this->next_token();
-			} while ( $found && ! $this->is_block_type( $block_name ) );
+				if ( ! $found ) {
+					break;
+				}
+
+				if ( $this->namespace_at === $this->name_at ) {
+					$matches = (
+						isset( $core_name ) &&
+						strlen( $core_name ) === $this->name_length &&
+						0 === substr_compare( $text, $core_name, $this->name_at, $this->name_length )
+					);
+				} else {
+					$length  = $this->name_at + $this->name_length - $this->namespace_at;
+					$matches = (
+						strlen( $block_type ) === $length &&
+						0 === substr_compare( $text, $block_type, $this->namespace_at, $length )
+					);
+				}
+			} while ( ! $matches );
 		}
 
 		$this->skip_html_spans = false;

tests/phpunit/tests/block-processor/wpBlockProcessor.php

@@ -1717,9 +1717,10 @@ public static function data_documents_and_delimiter_searches(): array {
 			'Ends in <!-'           => 'text<!-',
 			'Block, then ends in <' => '<!-- wp:group -->text<',
 			'Ends in delimiter'     => 'text<!-- wp:paragraph /-->',
+			'Explicit namespaces'   => '<!-- wp:core/paragraph --><!-- wp:paragraph /--><!-- wp:my/paragraph /--><!-- /wp:core/paragraph -->',
 		);
 
-		$block_types = array( null, 'paragraph', 'core/group', 'my/block', '*', 'freeform', 'core/freeform' );
+		$block_types = array( null, 'paragraph', 'core/paragraph', 'core/group', 'my/block', 'my/paragraph', '*', 'freeform', 'core/freeform', 'core/', 'core/my/paragraph' );
 
 		$data = array();
 		foreach ( $documents as $document_name => $html ) {