Fix Perfomance Issues of TexUtil

TexUtil gets instanciated and loads a json for each node in Literal and Fun1. This is not necessary since it takes much RAM and time to load the corresponding JSON from files.

Bug: T321599

Change-Id: I91855ebc4437f075302ae13d367ca4902cc0f3ba

src/TexVC/Nodes/Fun1.php

@@ -19,7 +19,7 @@ class Fun1 extends TexNode {
 		parent::__construct( $fname, $arg );
 		$this->fname = $fname;
 		$this->arg = $arg;
-		$this->tu = new TexUtil();
+		$this->tu = TexUtil::getInstance();
 	}
 
 	/**

src/TexVC/Nodes/Literal.php

@@ -16,8 +16,7 @@ class Literal extends TexNode {
 	public function __construct( string $arg ) {
 		parent::__construct( $arg );
 		$this->arg = $arg;
-		$tu = new TexUtil();
-		$this->literals = array_keys( $tu->getBaseElements()['is_literal'] );
+		$this->literals = array_keys( TexUtil::getInstance()->getBaseElements()['is_literal'] );
 		$this->extendedLiterals = $this->literals;
 		array_push( $this->extendedLiterals,  '\\infty', '\\emptyset' );
 	}

src/TexVC/Parser.php

@@ -9536,7 +9536,7 @@ class Parser {
 
     /* BEGIN initializer code */
 
-    $this->tu = new TexUtil();
+    $this->tu = TexUtil::getInstance();
     # get reference of the options for usage in functions.
 
 
@@ -9566,4 +9566,4 @@ class Parser {
     }
   }
 
-};
+};

src/TexVC/TexUtil.php

@@ -7,6 +7,7 @@ namespace MediaWiki\Extension\Math\TexVC;
 use MWException;
 
 class TexUtil {
+	private static $instance = null;
 	private $allFunctions;
 	private $baseElements;
 
@@ -15,7 +16,7 @@ class TexUtil {
 	 * allFunctions holds the root-level function keys
 	 * other objects are second level elements and hold all functions which are assigned to this second level elements
 	 */
-	public function __construct() {
+	private function __construct() {
 		$jsonContent = $this->getJSON();
 		// dynamically create functions from the content
 		$this->allFunctions = [];
@@ -41,6 +42,18 @@ class TexUtil {
 		}
 	}
 
+	public static function removeInstance() {
+		self::$instance = null;
+	}
+
+	public static function getInstance() {
+		if ( self::$instance == null ) {
+			self::$instance = new TexUtil();
+		}
+
+		return self::$instance;
+	}
+
 	/**
 	 * Returning the base elements array.
 	 * This is only used for testing in TexUtilTest.php.

src/TexVC/TexVC.php

@@ -24,7 +24,7 @@ class TexVC {
 
 	public function __construct() {
 		$this->parser = new Parser();
-		$this->tu = new TexUtil();
+		$this->tu = TexUtil::getInstance();
 	}
 
 	private function strStartsWith( $haystack, $needle ): bool {

src/TexVC/parser.pegjs

@@ -1,6 +1,7 @@
 /** PEGjs lexer/parser */
 {
-$this->tu = new TexUtil();
+$this->tu = TexUtil::getInstance();
+
 # get reference of the options for usage in functions.
 
 

tests/phpunit/unit/TexVC/TexUtilTest.php

@@ -11,10 +11,11 @@ use MediaWikiUnitTestCase;
 class TexUtilTest extends MediaWikiUnitTestCase {
 
 	/**
-	 * Basic test for tex util.
+	 * Basic test for TexUtil
 	 */
 	public function testTexUtil() {
-		$tu = new TexUtil();
+		TexUtil::removeInstance();
+		$tu = TexUtil::getInstance();
 		// Testing all functions
 		$this->assertTrue( $tu->getAllFunctionsAt( "\\AA" ) );
 		$this->assertFalse( $tu->getAllFunctionsAt( "\\notlisted" ) );
@@ -28,7 +29,7 @@ class TexUtilTest extends MediaWikiUnitTestCase {
 	 * @return void
 	 */
 	public function testChecksum() {
-		$tu = new TexUtil();
+		$tu = TexUtil::getInstance();
 
 		$out = [];
 		$sets = [