Merge pull request #1411 from NativeScript/darind/workers-json-stringify

Use the built-in JSON.stringify for cross workers communication

Author: vtrifonov

CHANGELOG.md

@@ -25,6 +25,8 @@
     The application crashed because of an uncaught exception. You can look at "stackTrace" or "nativeException" for more detailed information about the exception.
     ```
 
+- [The built-in `JSON.stringify` method is used for cross workers communication](https://github.com/NativeScript/android-runtime/issues/1408). Circular object references are no longer supported and attempting to send such object will throw an exception.
+
 5.4.0
 ==
 

test-app/app/src/main/assets/app/shared

@@ -992,7 +992,7 @@ CallbackHandlers::WorkerObjectPostMessageCallback(const v8::FunctionCallbackInfo
                                            ArgConverter::ConvertToV8String(isolate, "workerId"),
                                            jsId);
 
-        Local<String> msg = tns::JsonStringifyObject(isolate, args[0])->ToString(isolate);
+        Local<String> msg = tns::JsonStringifyObject(isolate, args[0], false);
         auto context = isolate->GetCurrentContext();
         // get worker's ID that is associated on the other side - in Java
         auto id = jsId->Int32Value(context).ToChecked();
@@ -1090,7 +1090,7 @@ CallbackHandlers::WorkerGlobalPostMessageCallback(const v8::FunctionCallbackInfo
             return;
         }
 
-        Local<String> msg = tns::JsonStringifyObject(isolate, args[0])->ToString(isolate);
+        Local<String> msg = tns::JsonStringifyObject(isolate, args[0], false);
 
         JEnv env;
         auto mId = env.GetStaticMethodID(RUNTIME_CLASS, "sendMessageFromWorkerToMain",

test-app/runtime/src/main/cpp/CallbackHandlers.cpp

@@ -66,34 +66,35 @@ Local<Function> GetSmartJSONStringifyFunction(Isolate* isolate) {
     return smartStringifyPersistentFunction->Get(isolate);
 }
 
-Local<String> tns::JsonStringifyObject(Isolate* isolate, Handle<v8::Value> value) {
+Local<String> tns::JsonStringifyObject(Isolate* isolate, Handle<v8::Value> value, bool handleCircularReferences) {
     if (value.IsEmpty()) {
         return String::Empty(isolate);
     }
 
-    Local<Function> smartJSONStringifyFunction = GetSmartJSONStringifyFunction(isolate);
+    if (handleCircularReferences) {
+        Local<Function> smartJSONStringifyFunction = GetSmartJSONStringifyFunction(isolate);
 
-    if (!smartJSONStringifyFunction.IsEmpty()) {
-        if (value->IsObject()) {
-            v8::Local<v8::Value> resultValue;
-            v8::TryCatch tc(isolate);
+        if (!smartJSONStringifyFunction.IsEmpty()) {
+            if (value->IsObject()) {
+                v8::Local<v8::Value> resultValue;
+                v8::TryCatch tc(isolate);
 
-            Local<Value> args[] = { value->ToObject(isolate) };
-            auto success = smartJSONStringifyFunction->Call(isolate->GetCurrentContext(), Undefined(isolate), 1, args).ToLocal(&resultValue);
+                Local<Value> args[] = { value->ToObject(isolate) };
+                auto success = smartJSONStringifyFunction->Call(isolate->GetCurrentContext(), Undefined(isolate), 1, args).ToLocal(&resultValue);
 
-            if (success && !tc.HasCaught()) {
-                return resultValue->ToString(isolate);
+                if (success && !tc.HasCaught()) {
+                    return resultValue->ToString(isolate);
+                }
             }
         }
     }
 
     v8::Local<v8::String> resultString;
     v8::TryCatch tc(isolate);
-    auto success = v8::JSON::Stringify(isolate->GetCurrentContext(), value->ToObject(isolate), ArgConverter::ConvertToV8String(isolate, "2")).ToLocal(&resultString);
+    auto success = v8::JSON::Stringify(isolate->GetCurrentContext(), value->ToObject(isolate)).ToLocal(&resultString);
 
     if (!success && tc.HasCaught()) {
-        auto message = tc.Message()->Get();
-        resultString = v8::String::Concat(isolate, ArgConverter::ConvertToV8String(isolate, "Couldn't convert object to a JSON string: "), message);
+        throw NativeScriptException(tc);
     }
 
     return resultString;

test-app/runtime/src/main/cpp/V8GlobalHelpers.cpp

@@ -8,7 +8,7 @@
 #include <map>
 
 namespace tns {
-v8::Local<v8::String> JsonStringifyObject(v8::Isolate* isolate, v8::Handle<v8::Value> value);
+v8::Local<v8::String> JsonStringifyObject(v8::Isolate* isolate, v8::Handle<v8::Value> value, bool handleCircularReferences = true);
 
 bool V8GetPrivateValue(v8::Isolate* isolate, const v8::Local<v8::Object>& obj, const v8::Local<v8::String>& propName, v8::Local<v8::Value>& out);