Reuse SQLite driver MySQL parser

Author: adamziel

packages/mysql-on-sqlite/src/mysql/class-wp-mysql-parser.php

@@ -8,6 +8,17 @@ class WP_MySQL_Parser extends WP_Parser {
 	 */
 	private $current_ast;
 
+	/**
+	 * Reset this parser with a new token stream.
+	 *
+	 * @param array<WP_Parser_Token> $tokens The parser tokens.
+	 */
+	public function reset_tokens( array $tokens ): void {
+		$this->tokens      = $tokens;
+		$this->position    = 0;
+		$this->current_ast = null;
+	}
+
 	/**
 	 * Parse the next query from the input SQL string.
 	 *

packages/mysql-on-sqlite/src/sqlite/class-wp-pdo-mysql-on-sqlite.php

@@ -410,6 +410,13 @@ class WP_PDO_MySQL_On_SQLite extends PDO {
 	 */
 	private static $mysql_grammar;
 
+	/**
+	 * A reusable parser instance for MySQL queries.
+	 *
+	 * @var WP_MySQL_Parser|null
+	 */
+	private $mysql_parser = null;
+
 	/**
 	 * The main database name.
 	 *
@@ -1160,11 +1167,27 @@ public function create_parser( string $query ): WP_MySQL_Parser {
 		);
 		if ( $lexer instanceof WP_MySQL_Native_Lexer ) {
 			$tokens = $lexer->native_token_stream();
-			return new WP_MySQL_Parser( self::$mysql_grammar, $tokens );
+			return $this->reset_or_create_parser( $tokens );
 		}
 
 		$tokens = $lexer->remaining_tokens();
-		return new WP_MySQL_Parser( self::$mysql_grammar, $tokens );
+		return $this->reset_or_create_parser( $tokens );
+	}
+
+	/**
+	 * Reset the reusable parser with new tokens or create it on first use.
+	 *
+	 * @param  array<WP_Parser_Token>|object $tokens Parser tokens.
+	 * @return WP_MySQL_Parser                       A parser initialized for the token stream.
+	 */
+	private function reset_or_create_parser( $tokens ): WP_MySQL_Parser {
+		if ( null === $this->mysql_parser || ! method_exists( $this->mysql_parser, 'reset_tokens' ) ) {
+			$this->mysql_parser = new WP_MySQL_Parser( self::$mysql_grammar, $tokens );
+		} else {
+			$this->mysql_parser->reset_tokens( $tokens );
+		}
+
+		return $this->mysql_parser;
 	}
 
 	/**

packages/php-ext-wp-mysql-parser/src/lib.rs

@@ -1587,6 +1587,18 @@ impl WpMySqlNativeParser {
         })
     }
 
+    pub fn reset_tokens(&mut self, tokens: &mut Zval) -> PhpResult<()> {
+        let (token_source, token_ids) = export_tokens(tokens)?;
+
+        self.token_source = Arc::new(token_source);
+        self.token_ids = token_ids;
+        self.position = 0;
+        self.current_ast = None;
+        self.current_php_ast = None;
+
+        Ok(())
+    }
+
     pub fn parse(&mut self) -> PhpResult<Zval> {
         stacker::maybe_grow(STACK_RED_ZONE, STACK_GROW_SIZE, || {
             let ast = self.parse_native_ast()?;