fix differing eval behavior between eval and scopedEval

swimmadude66 · Jul 30, 2024 · 8eaecb6 · 8eaecb6
1 parent 9e6ce27
commit 8eaecb6
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Showing 3 changed files with 58 additions and 13 deletions.
diff --git a/packages/vm/package.json b/packages/vm/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@tectonica/vm",
-  "version": "1.0.1",
+  "version": "1.0.2",
   "module": "dist/esm/index.js",
   "types": "dist/types/index.d.ts",
   "exports": {

diff --git a/packages/vm/src/vm.ts b/packages/vm/src/vm.ts
@@ -13,6 +13,7 @@ import {
   type QuickJSAsyncVariant,
   type QuickJSSyncVariant,
   Scope,
+  QuickJSHandle,
 } from 'quickjs-emscripten'
 import { ModuleOptions, VMInitOpts } from './types'
 import { Marshaller } from './marshal'
@@ -31,6 +32,8 @@ export class VMManager {
     resolve: () => void
   }
 
+  private vmContextMapKey: string = generateMagicToken({ prefix: '__context_map_', suffix: '_key' })
+
   constructor() {}
 
   async init({ debug, async, runtimeOpts, contextOpts, variant, variantOptions }: VMInitOpts = {}) {
@@ -127,20 +130,21 @@ export class VMManager {
   scopedEval(code: string, contextVars: Record<string, any>) {
     const vm = this.requireVM()
     const scope = new Scope()
-    const scopeArgName = generateMagicToken({ prefix: '__context_args' })
-    const scopedFunc = scope.manage(
-      vm.unwrapResult(
-        vm.evalCode(`(${scopeArgName} = {}) => {
+    const contextId = generateMagicToken({ prefix: '__scoped_context_' })
+    try {
+      const contextHandle = scope.manage(this.marshaller.marshal(contextVars))
+      const contextMapHandle = scope.manage(this.getOrCreateContextMap(vm))
+      vm.setProp(contextMapHandle, contextId, contextHandle)
+      const resultHandle = scope.manage(
+        vm.unwrapResult(
+          vm.evalCode(`
           {
-            const { ${Object.keys(contextVars).join(', ')} } = ${scopeArgName}
-            return (${code})
-          }
-        }`)
+            const { ${Object.keys(contextVars).join(', ')} } = globalThis[Symbol.for('${this.vmContextMapKey}')]['${contextId}']
+            ${code}
+          }`)
+        )
       )
-    )
-    const contextHandle = scope.manage(this.marshaller.marshal(contextVars))
-    try {
-      const resultHandle = scope.manage(vm.unwrapResult(vm.callFunction(scopedFunc, vm.global, contextHandle)))
+      vm.setProp(contextMapHandle, contextId, vm.undefined)
       return this.marshaller.unmarshal(resultHandle)
     } finally {
       scope.dispose()
@@ -168,4 +172,23 @@ export class VMManager {
     }
     return variant
   }
+
+  private getOrCreateContextMap(vm: QuickJSContext): QuickJSHandle {
+    const contextMapHandle = vm.unwrapResult(
+      vm.evalCode(`
+      {
+        (() => {
+          const cacheSymbol = Symbol.for('${this.vmContextMapKey}')
+          let cacheMap = globalThis[cacheSymbol]
+          if (!cacheMap) {
+            cacheMap = {}
+            Object.defineProperty(globalThis, cacheSymbol, { value: cacheMap, enumerable: false, configurable: false, writable: false})
+          }
+          return cacheMap 
+        })()
+      }
+    `)
+    )
+    return contextMapHandle
+  }
 }
diff --git a/packages/vm/tests/vm.test.ts b/packages/vm/tests/vm.test.ts
@@ -136,5 +136,27 @@ describe('VMManager', () => {
       expect(domProxy).not.to.be.null
       expect(typeof domProxy).to.equal('object')
     })
+
+    it('handles scoped dom proxying', () => {
+      const btn = document.createElement('button')
+      const context = { btn, counter: { val: 0 } }
+      const btnProxy = vm.scopedEval(
+        `
+        function run() {
+          const b = btn
+          b.addEventListener('click', () => ++counter.val)
+          return b
+        }
+        run()
+        `,
+        context
+      )
+      expect(btnProxy).not.to.be.null
+      expect(typeof btnProxy).to.equal('object')
+      btn.click()
+      expect(context.counter.val).to.equal(1)
+      btnProxy.click()
+      expect(context.counter.val).to.equal(2)
+    })
   })
 })