vm context with accessors

true copy of sandbox properties

catch sealed errors, pass global's prototype to CloneObject

Fixes nodejs#1673

Author: indutny

lib/vm.js

@@ -21,6 +21,19 @@
 
 var binding = process.binding('evals');
 
+binding.NodeScript._setCloneMethod(function(source, target) {
+  Object.getOwnPropertyNames(source).forEach(function(key) {
+    try {
+      var desc = Object.getOwnPropertyDescriptor(source, key);
+      if (desc.value === source) desc.value = target;
+
+      Object.defineProperty(target, key, desc);
+    } catch (e) {
+      // Catch sealed properties errors
+    }
+  });
+});
+
 exports.Script = binding.NodeScript;
 exports.createScript = function(code, ctx, name) {
   return new exports.Script(code, ctx, name);

src/node_script.cc

@@ -37,9 +37,11 @@ using v8::TryCatch;
 using v8::String;
 using v8::Exception;
 using v8::Local;
+using v8::Null;
 using v8::Array;
 using v8::Persistent;
 using v8::Integer;
+using v8::Function;
 using v8::FunctionTemplate;
 
 
@@ -94,10 +96,23 @@ class WrappedScript : ObjectWrap {
   static Handle<Value> CompileRunInThisContext(const Arguments& args);
   static Handle<Value> CompileRunInNewContext(const Arguments& args);
 
+  static Handle<Value> SetCloneMethod(const Arguments& args);
+
   Persistent<Script> script_;
 };
 
 
+Persistent<Function> cloneObjectMethod;
+
+void CloneObject(Handle<Object> recv,
+                 Handle<Value> source, Handle<Value> target) {
+  HandleScope scope;
+
+  Handle<Value> args[] = {source, target};
+  cloneObjectMethod->Call(recv, 2, args);
+}
+
+
 void WrappedContext::Initialize(Handle<Object> target) {
   HandleScope scope;
 
@@ -177,6 +192,10 @@ void WrappedScript::Initialize(Handle<Object> target) {
                             "runInNewContext",
                             WrappedScript::RunInNewContext);
 
+  NODE_SET_PROTOTYPE_METHOD(constructor_template,
+                            "_setCloneMethod",
+                            WrappedScript::SetCloneMethod);
+
   NODE_SET_METHOD(constructor_template,
                   "createContext",
                   WrappedScript::CreateContext);
@@ -193,6 +212,10 @@ void WrappedScript::Initialize(Handle<Object> target) {
                   "runInNewContext",
                   WrappedScript::CompileRunInNewContext);
 
+  NODE_SET_METHOD(constructor_template,
+                  "_setCloneMethod",
+                  WrappedScript::SetCloneMethod);
+
   target->Set(String::NewSymbol("NodeScript"),
               constructor_template->GetFunction());
 }
@@ -225,14 +248,8 @@ Handle<Value> WrappedScript::CreateContext(const Arguments& args) {
 
   if (args.Length() > 0) {
     Local<Object> sandbox = args[0]->ToObject();
-    Local<Array> keys = sandbox->GetPropertyNames();
 
-    for (uint32_t i = 0; i < keys->Length(); i++) {
-      Handle<String> key = keys->Get(Integer::New(i))->ToString();
-      Handle<Value> value = sandbox->Get(key);
-      if(value == sandbox) { value = context; }
-      context->Set(key, value);
-    }
+    CloneObject(args.This(), sandbox, context);
   }
 
 
@@ -275,6 +292,15 @@ Handle<Value> WrappedScript::CompileRunInNewContext(const Arguments& args) {
     WrappedScript::EvalMachine<compileCode, newContext, returnResult>(args);
 }
 
+Handle<Value> WrappedScript::SetCloneMethod(const Arguments& args) {
+  HandleScope scope;
+
+  Local<Function> cloneObjectMethod_ = Local<Function>::Cast(args[0]);
+  cloneObjectMethod = Persistent<Function>::New(cloneObjectMethod_);
+
+  return scope.Close(Null());
+}
+
 
 template <WrappedScript::EvalInputFlags input_flag,
           WrappedScript::EvalContextFlags context_flag,
@@ -343,14 +369,7 @@ Handle<Value> WrappedScript::EvalMachine(const Arguments& args) {
 
     // Copy everything from the passed in sandbox (either the persistent
     // context for runInContext(), or the sandbox arg to runInNewContext()).
-    keys = sandbox->GetPropertyNames();
-
-    for (i = 0; i < keys->Length(); i++) {
-      Handle<String> key = keys->Get(Integer::New(i))->ToString();
-      Handle<Value> value = sandbox->Get(key);
-      if (value == sandbox) { value = context->Global(); }
-      context->Global()->Set(key, value);
-    }
+    CloneObject(args.This(), sandbox, context->Global()->GetPrototype());
   }
 
   // Catch errors
@@ -408,13 +427,7 @@ Handle<Value> WrappedScript::EvalMachine(const Arguments& args) {
 
   if (context_flag == userContext || context_flag == newContext) {
     // success! copy changes back onto the sandbox object.
-    keys = context->Global()->GetPropertyNames();
-    for (i = 0; i < keys->Length(); i++) {
-      Handle<String> key = keys->Get(Integer::New(i))->ToString();
-      Handle<Value> value = context->Global()->Get(key);
-      if (value == context->Global()) { value = sandbox; }
-      sandbox->Set(key, value);
-    }
+    CloneObject(args.This(), context->Global()->GetPrototype(), sandbox);
   }
 
   if (context_flag == newContext) {

test/simple/test-vm-create-context-accessors.js

@@ -0,0 +1,26 @@
+var common = require('../common');
+var assert = require('assert');
+var vm = require('vm');
+
+var ctx = {};
+
+Object.defineProperty(ctx, 'getter', {
+  get: function() {
+    return 'ok';
+  }
+});
+
+var val;
+Object.defineProperty(ctx, 'setter', {
+  set: function(_val) {
+    val = _val;
+  },
+  get: function() {
+    return 'ok=' + val;
+  }
+});
+
+ctx = vm.createContext(ctx);
+
+var result = vm.runInContext('setter = "test";[getter,setter]', ctx);
+assert.deepEqual(result, ['ok', 'ok=test']);