kmx.io/prism.js

diff --git a/tests/checks/extend.js b/tests/checks/extend.js
deleted file mode 100644
index b699dd3..0000000
--- a/tests/checks/extend.js
+++ /dev/null
@@ -1,20 +0,0 @@
-const { testFunction } = require('./../helper/check-functionality');
-
-function extendTest(id, redef) {
-	const details = `\nextend("${id}", ${redef})`;
-
-	// type checks
-	if (typeof id !== 'string') {
-		throw new TypeError(`The id argument has to be a 'string'.` + details);
-	}
-	if (typeof redef !== 'object') {
-		throw new TypeError(`The redef argument has to be an 'object'.` + details);
-	}
-
-
-	if (!(id in Prism.languages)) {
-		throw new Error(`Cannot extend '${id}' because it is not defined in Prism.languages.`);
-	}
-}
-
-testFunction('extend', Prism.languages, extendTest);
diff --git a/tests/checks/insert-before.js b/tests/checks/insert-before.js
deleted file mode 100644
index 8536345..0000000
--- a/tests/checks/insert-before.js
+++ /dev/null
@@ -1,32 +0,0 @@
-const { testFunction } = require('./../helper/check-functionality');
-
-function insertBeforeTest(inside, before, insert, root) {
-	const details = `\ninsertBefore("${inside}", "${before}", ${insert}, ${root})`;
-
-	// type checks
-	if (typeof inside !== 'string') {
-		throw new TypeError(`The inside argument has to be a 'string'.` + details);
-	}
-	if (typeof before !== 'string') {
-		throw new TypeError(`The before argument has to be a 'string'.` + details);
-	}
-	if (typeof insert !== 'object') {
-		throw new TypeError(`The insert argument has to be an 'object'.` + details);
-	}
-	if (root && typeof root !== 'object') {
-		throw new TypeError(`The root argument has to be an 'object' if defined.` + details);
-	}
-
-
-	root = root || Prism.languages;
-	var grammar = root[inside];
-
-	if (typeof grammar !== 'object') {
-		throw new Error(`The grammar "${inside}" has to be an 'object' not '${typeof grammar}'.`);
-	}
-	if (!(before in grammar)) {
-		throw new Error(`"${before}" has to be a key of the grammar "${inside}".`);
-	}
-}
-
-testFunction('insertBefore', Prism.languages, insertBeforeTest);
diff --git a/tests/helper/check-functionality.js b/tests/helper/check-functionality.js
deleted file mode 100644
index 0192d0c..0000000
--- a/tests/helper/check-functionality.js
+++ /dev/null
@@ -1,13 +0,0 @@
-"use strict";
-
-module.exports = {
-	testFunction(name, object, tester) {
-		const func = object[name];
-
-		object[name] = function () {
-			tester.apply(this, arguments);
-			return func.apply(this, arguments);
-		};
-	}
-
-}
diff --git a/tests/helper/checks.js b/tests/helper/checks.js
new file mode 100644
index 0000000..f926626
--- /dev/null
+++ b/tests/helper/checks.js
@@ -0,0 +1,63 @@
+"use strict";
+
+function testFunction(name, object, tester) {
+	const func = object[name];
+
+	object[name] = function () {
+		tester.apply(this, arguments);
+		return func.apply(this, arguments);
+	};
+}
+
+module.exports = (Prism) => {
+
+	function extendTest(id, redef) {
+		const details = `\nextend("${id}", ${redef})`;
+
+		// type checks
+		if (typeof id !== 'string') {
+			throw new TypeError(`The id argument has to be a 'string'.` + details);
+		}
+		if (typeof redef !== 'object') {
+			throw new TypeError(`The redef argument has to be an 'object'.` + details);
+		}
+
+
+		if (!(id in Prism.languages)) {
+			throw new Error(`Cannot extend '${id}' because it is not defined in Prism.languages.`);
+		}
+	}
+
+	function insertBeforeTest(inside, before, insert, root) {
+		const details = `\ninsertBefore("${inside}", "${before}", ${insert}, ${root})`;
+
+		// type checks
+		if (typeof inside !== 'string') {
+			throw new TypeError(`The inside argument has to be a 'string'.` + details);
+		}
+		if (typeof before !== 'string') {
+			throw new TypeError(`The before argument has to be a 'string'.` + details);
+		}
+		if (typeof insert !== 'object') {
+			throw new TypeError(`The insert argument has to be an 'object'.` + details);
+		}
+		if (root && typeof root !== 'object') {
+			throw new TypeError(`The root argument has to be an 'object' if defined.` + details);
+		}
+
+
+		root = root || Prism.languages;
+		var grammar = root[inside];
+
+		if (typeof grammar !== 'object') {
+			throw new Error(`The grammar "${inside}" has to be an 'object' not '${typeof grammar}'.`);
+		}
+		if (!(before in grammar)) {
+			throw new Error(`"${before}" has to be a key of the grammar "${inside}".`);
+		}
+	}
+
+	testFunction('extend', Prism.languages, extendTest);
+	testFunction('insertBefore', Prism.languages, insertBeforeTest);
+
+};
diff --git a/tests/helper/prism-loader.js b/tests/helper/prism-loader.js
index 562e02d..2d70c98 100644
--- a/tests/helper/prism-loader.js
+++ b/tests/helper/prism-loader.js
@@ -1,11 +1,11 @@
 "use strict";
 
 const fs = require("fs");
-const vm = require("vm");
 const { getAllFiles } = require("./test-discovery");
 const components = require("../../components.json");
 const getLoader = require("../../dependencies");
 const languagesCatalog = components.languages;
+const coreChecks = require('./checks');
 
 
 /**
@@ -14,6 +14,13 @@ const languagesCatalog = components.languages;
  * @property {Set<string>} loaded A set of loaded components.
  */
 
+/** @type {Map<string, string>} */
+const fileSourceCache = new Map();
+/** @type {() => any} */
+let coreSupplierFunction = null;
+/** @type {Map<string, (Prism: any) => void>} */
+const languageCache = new Map();
+
 module.exports = {
 
 	/**
@@ -51,9 +58,15 @@ module.exports = {
 				throw new Error(`Language '${id}' not found.`);
 			}
 
-			// load the language itself
-			const languageSource = this.loadComponentSource(id);
-			context.Prism = this.runFileWithContext(languageSource, { Prism: context.Prism }).Prism;
+			// get the function which adds the language from cache
+			let languageFunction = languageCache.get(id);
+			if (languageFunction === undefined) {
+				// make a function from the code which take "Prism" as an argument, so the language grammar
+				// references the function argument
+				const func = new Function('Prism', this.loadComponentSource(id));
+				languageCache.set(id, languageFunction = (Prism) => func(Prism));
+			}
+			languageFunction(context.Prism);
 
 			context.loaded.add(id);
 		});
@@ -69,45 +82,26 @@ module.exports = {
 	 * @returns {Prism}
 	 */
 	createEmptyPrism() {
-		const coreSource = this.loadComponentSource("core");
-		const context = this.runFileWithContext(coreSource);
-
-		for (const testSource of this.getChecks().map(src => this.loadFileSource(src))) {
-			context.Prism = this.runFileWithContext(testSource, {
-				Prism: context.Prism,
-				/**
-				 * A pseudo require function for the checks.
-				 *
-				 * This function will behave like the regular `require` in real modules when called form a check file.
-				 *
-				 * @param {string} id The id of relative path to require.
-				 */
-				require(id) {
-					if (id.startsWith('./')) {
-						// We have to rewrite relative paths starting with './'
-						return require('./../checks/' + id.substr(2));
-					} else {
-						// This might be an id like 'mocha' or 'fs' or a relative path starting with '../'.
-						// In both cases we don't have to change anything.
-						return require(id);
-					}
-				}
-			}).Prism;
+		if (!coreSupplierFunction) {
+			const source = this.loadComponentSource("core");
+			// Core exports itself in 2 ways:
+			//  1) it uses `module.exports = Prism` which what we'll use
+			//  2) it uses `global.Prism = Prism` which we want to sabotage to prevent leaking
+			const func = new Function('module', 'global', source);
+			coreSupplierFunction = () => {
+				const module = {
+					// that's all we care about
+					exports: {}
+				};
+				func(module, {});
+				return module.exports;
+			};
 		}
-
-		return context.Prism;
+		const Prism = coreSupplierFunction();
+		coreChecks(Prism);
+		return Prism;
 	},
 
-
-	/**
-	 * Cached file sources, to prevent massive HDD work
-	 *
-	 * @private
-	 * @type {Object.<string, string>}
-	 */
-	fileSourceCache: {},
-
-
 	/**
 	 * Loads the given component's file source as string
 	 *
@@ -127,36 +121,10 @@ module.exports = {
 	 * @returns {string}
 	 */
 	loadFileSource(src) {
-		return this.fileSourceCache[src] = this.fileSourceCache[src] || fs.readFileSync(src, "utf8");
-	},
-
-
-	checkCache: null,
-
-	/**
-	 * Returns a list of files which add additional checks to Prism functions.
-	 *
-	 * @returns {ReadonlyArray<string>}
-	 */
-	getChecks() {
-		return this.checkCache = this.checkCache || getAllFiles(__dirname + "/../checks");
-	},
-
-
-	/**
-	 * Runs a VM for a given file source with the given context
-	 *
-	 * @private
-	 * @param {string} fileSource
-	 * @param {*} [context={}]
-	 *
-	 * @returns {*}
-	 */
-	runFileWithContext(fileSource, context = {}) {
-		// we don't have to pass our console but it's the only way these scripts can talk
-		// not supplying console here means that all references to `console` inside them will refer to a no-op console
-		context.console = console;
-		vm.runInNewContext(fileSource, context);
-		return context;
+		let content = fileSourceCache.get(src);
+		if (content === undefined) {
+			fileSourceCache.set(src, content = fs.readFileSync(src, "utf8"));
+		}
+		return content;
 	}
 };