Merge d52ae56 into 6bb5ffd

src/index.ts

@@ -10,19 +10,23 @@ import { hoist } from './compile/helper'
 
 export interface SvalOptions {
   ecmaVer?: 3 | 5 | 6 | 7 | 8 | 9 | 10 | 2015 | 2016 | 2017 | 2018 | 2019
-  sandBox?: boolean
+  sandBox?: boolean,
+  stepLimit?: number
 }
 
 class Sval {
   static version: string = version
 
   private options: Options = {}
   private state = new State()
+  private stepLimit: number | null
 
   exports: { [name: string]: any } = {}
 
   constructor(options: SvalOptions = {}) {
-    let { ecmaVer = 9, sandBox = true } = options
+    let { ecmaVer = 9, sandBox = true, stepLimit = null } = options
+
+    this.stepLimit = stepLimit;
 
     ecmaVer -= ecmaVer < 2015 ? 0 : 2009 // format ecma edition
 
@@ -74,7 +78,7 @@ class Sval {
     //   const opCode = this.state.opCodes[i]
     //   console.log(i, (OP as any)[opCode.op], typeof opCode.val === 'undefined' ? '' : opCode.val)
     // }
-    execute(this.state)
+    execute(this.state, this.stepLimit)
   }
 }
 

src/jsvm/index.ts

@@ -522,6 +522,20 @@ function step(state: State) {
   return signal
 }
 
-export default function execute(state: State) {
+export default function execute(state: State, stepLimit: number | null) {
+  if (stepLimit === null) {
   while (state.pc < state.opCodes.length) step(state)
+  } else {
+    // Restrict number of steps.
+    let stepCounter: number = 0
+
+    while (state.pc < state.opCodes.length && stepCounter < stepLimit) {
+      step(state)
+      stepCounter++
+    }
+
+    if (stepCounter >= stepLimit) {
+      throw new Error('Execution limit exceeded')
+    }
+  }
 }

tests/bootstrap.test1.ts

@@ -22,6 +22,18 @@ describe('testing src/index.ts', () => {
     interpreter.run(`!async function(){${code}}()`)
   })
 
+  it('should support execution limit', () => {
+    const interpreter = new Sval({
+      stepLimit: 100
+    })
+
+    try {
+      interpreter.run(`while(true){}`);
+    } catch (ex) {
+      expect(ex.message).toBe('Execution limit exceeded')
+    }
+  })
+
   it('should support global mode', () => {
     const interpreter = new Sval({
       sandBox: false