Add nashorn sandbox

build.gradle

@@ -20,6 +20,7 @@ group = mod_group_id
 
 repositories {
 	mavenLocal()
+	maven { url 'https://repo.nea.moe/releases/' }
 }
 
 base {
@@ -52,7 +53,10 @@ dependencies {
 	// And its provides the option to then use net.minecraft as the group, and one of; client, server or joined as the module name, plus the game version as version.
 	// For all intends and purposes: You can treat this dependency as if it is a normal library you would use.
 	implementation "net.neoforged:neoforge:${neo_version}"
-	libraries 'org.mozilla:rhino-engine:1.7.15'
+	libraries('org.javadelight:delight-nashorn-sandbox:0.4.2-jpms') {
+		exclude(group: "org.ow2.asm")
+		exclude(group: "org.slf4j")
+	}
 	// Example optional mod dependency with JEI
 	// The JEI API is declared for compile time use, while the full JEI artifact is used at runtime
 	// compileOnly "mezz.jei:jei-${mc_version}-common-api:${jei_version}"

src/main/java/dev/exhq/ajarc/computer/ComputerBlockEntity.java

@@ -35,7 +35,7 @@ public class ComputerBlockEntity extends BlockEntity {
 	private static final MapCodec<ComputerTerminal> screenCodec = ComputerTerminal.CODEC
 			.fieldOf("screen")
 			.setPartial(() -> ComputerTerminal.ofSize(20, 30));
-	JsVm jsVm = new JsVm();
+	JsVm jsVm = new JsVm(this);
 	private List<String> lines = new ArrayList<>();
 
 	@Override
@@ -77,20 +77,17 @@ public class ComputerBlockEntity extends BlockEntity {
 
 	public void executeCommand(String line) {
 		lines.add("$ " + line);
-		lines.add(jsVm.evalJs(line));
-//		if (line.equals("small")) {
-//			screen = ComputerTerminal.ofSize(10, 20);
-//			lines.add("Made small!");
-//		} else if (line.equals("big")) {
-//			screen = ComputerTerminal.ofSize(20, 30);
-//			lines.add("Made big!");
-//		} else if (line.startsWith("add")) {
-//			var newline = line.replaceFirst("add ", "").split(" ");
-//			lines.add(JsVm.EvalJs("mathj.add("+newline[0]+","+newline[1]+")"));
-//		}
-//		else {
-//			lines.add("Made unknown!");
-//		}
+		if (line.equals("small")) {
+			screen = ComputerTerminal.ofSize(10, 20);
+			lines.add("Made small!");
+		} else if (line.equals("big")) {
+			screen = ComputerTerminal.ofSize(20, 30);
+			lines.add("Made big!");
+		} else if (line.startsWith("add")) {
+			lines.add(jsVm.add(69, 42) + "");
+		} else {
+			lines.add("Made unknown!");
+		}
 	}
 
 	public ComputerScreenUpdate getSyncPacket(int windowId) {

src/main/java/dev/exhq/ajarc/vm/JsVm.java

@@ -1,44 +1,53 @@
 package dev.exhq.ajarc.vm;
 
-import org.mozilla.javascript.Context;
-import org.mozilla.javascript.Scriptable;
-import org.mozilla.javascript.ScriptableObject;
-import org.mozilla.javascript.JavaScriptException;
+import delight.nashornsandbox.NashornSandbox;
+import delight.nashornsandbox.NashornSandboxes;
+import delight.nashornsandbox.internal.JsSanitizer;
+import dev.exhq.ajarc.Ajar;
+import dev.exhq.ajarc.computer.ComputerBlockEntity;
+import dev.exhq.ajarc.computer.ComputerTerminal;
+import net.minecraft.client.Minecraft;
+import org.apache.commons.io.IOUtils;
+
+import javax.script.ScriptException;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.Map;
 
 public class JsVm {
-	private Context cx;
-	private Scriptable scope;
+	private final NashornSandbox sandbox;
 
-	public JsVm() {
-		cx = Context.enter();
+	public JsVm(ComputerBlockEntity entity) {
+		sandbox = NashornSandboxes.create();
+		sandbox.inject("screen", new ScreenHelper(entity));
+	}
+
+	public record ScreenHelper(ComputerBlockEntity entity) {
+		public void setScreenSize(int rows, int cols) {
+			entity.setTerminal(ComputerTerminal.ofSize(rows, cols));
+		}
+	}
+
+	public int add(int left, int right) {
+		String text;
 		try {
-			scope = cx.initStandardObjects();
-			MathJ mathJ = new MathJ();
-			Object wrappedJsVm = Context.javaToJS(mathJ, scope);
-			ScriptableObject.putProperty(scope, "mathj", wrappedJsVm);
-		} finally {
-			Context.exit();
+			var stream = Minecraft.getInstance()
+			                      .getResourceManager()
+			                      .getResourceOrThrow(Ajar.identifier("script.js"))
+			                      .open();
+			text = IOUtils.toString(stream, StandardCharsets.UTF_8);
+		} catch (IOException e) {
+			throw new RuntimeException(e);
 		}
-	}
-
-	public String evalJs(String command) {
-		Context.enter();
+		var bindings = sandbox.createBindings();
+		bindings.put("left", left);
+		bindings.put("right", right);
 		try {
-			Object result = cx.evaluateString(scope, command, "<cmd>", 1, null);
-			return Context.toString(result);
-		} catch (JavaScriptException e) {
-			return e.getMessage();
-		} catch (Exception e) {
-			return e.getMessage();
-		} finally {
-			Context.exit();
-		}
+			sandbox.eval(text, bindings);
+		} catch (ScriptException e) {
+			throw new RuntimeException(e);
 		}
 
-	public void cleanup() {
-		if (cx != null) {
-			cx.exit();
-			cx = null;
-		}
+		return (int) (double) bindings.get("result");
 	}
 }

src/main/resources/assets/ajarc/script.js

@@ -0,0 +1,3 @@
+
+screen.setScreenSize(5, 30)
+result = left + right