Question

任何人都可以看到为什么对持久性函数pfunc_on_open的调用崩溃了？

Locker lock(isolate);
HandleScope scope(isolate);

v8::Local<v8::Context> context = v8::Local<v8::Context>::New(isolate, p_context);
Context::Scope context_scope(context);
Handle < v8::Object > global = context->Global();

Handle < Value > args[1];
if (event.compare(event_onopen) == 0) {

    args[0] = v8::String::NewFromUtf8(isolate,message.c_str());

    v8::Local<v8::Function> processOnOpen = v8::Local<v8::Function>::New(isolate, pfunc_on_open);

    processOnOpen->Call(global, 1, args);
}

Answer 1

该功能通过以下代码与javascript方法相关联：

void WebSocket::exposeWebSocket(Handle<ObjectTemplate> globalTemplate)
{

globalTemplate->Set(String::NewFromUtf8(isolate,"WebSocket"),
FunctionTemplate::New(isolate,WebSocketConstructor));}

void WebSocketConstructor（const v8 :: FunctionCallbackInfo＆amp; args） {

LOGD(LOG_TAG, "In WebSocketConstructor()");

 Locker lock(isolate);
 HandleScope scope(isolate);

 Handle<ObjectTemplate> websocket_templ= ObjectTemplate::New();
 websocket_templ->SetInternalFieldCount(1);

 // Object methods
 websocket_templ->Set(String::NewFromUtf8(isolate,"send"), FunctionTemplate::New(isolate,WebSocket::exposed_method_send));
 websocket_templ->Set(String::NewFromUtf8(isolate,"close"), FunctionTemplate::New(isolate,WebSocket::exposed_method_close));

 // Set up properties as event handlers
 websocket_templ->SetAccessor(String::NewFromUtf8(isolate,"onopen"), AccessorGetterCallback(WebSocket::GetOnCallback), AccessorSetterCallback(WebSocket::SetOnOpen));
 websocket_templ->SetAccessor(String::NewFromUtf8(isolate,"onmessage"), AccessorGetterCallback(WebSocket::GetOnCallback), AccessorSetterCallback(WebSocket::SetOnMessage));
 websocket_templ->SetAccessor(String::NewFromUtf8(isolate,"onerror"), AccessorGetterCallback(WebSocket::GetOnCallback), AccessorSetterCallback(WebSocket::SetOnFail));
 websocket_templ->SetAccessor(String::NewFromUtf8(isolate,"onclose"), AccessorGetterCallback(WebSocket::GetOnCallback), AccessorSetterCallback(WebSocket::SetOnClose));

 Handle<Object> ws_instance;

 if (!args[0].IsEmpty() && args[0]->IsString()) {

        String::Utf8Value p1(args[0]->ToString());

        LOGD(LOG_TAG, "WebSocketConstructor() - URL = %s", *p1);

        // Create a C++ instance of this type
        WebSocket* wsObject = new WebSocket(*p1);

        //Handle<Object> self = Handle<Object>::New(isolate, args.Holder() );

        ws_instance = websocket_templ->NewInstance();

         ws_instance->SetInternalField(0, v8::External::New(isolate, wsObject));

        args.GetReturnValue().Set(ws_instance);

     }

}

void WebSocket::SetOnOpen(Local<String> prop, Local<Value> value, const v8::PropertyCallbackInfo<void>& info) {

Locker lock(isolate);
HandleScope scope(isolate);

String::Utf8Value str(prop);

LOGD(LOG_TAG, "SetOnOpen(): property = %s", *str);

// Retrieve the WebSocket instance associated with this callback so the
// appropriate map object can be used to store the callback address
Handle < Object > self = info.Holder();
Handle < External > wrap = Handle < External > ::Cast(self->GetInternalField(0));

void* ptr = wrap->Value();

WebSocket* ws = static_cast<WebSocket*>(ptr);

if (value->IsFunction()) {

    // Store a persistent function handle in the callback map
    Handle<Function> callback = Handle<Function>::Cast(value);

    ws->pfunc_on_open.Reset(isolate, callback);

    if(callback.IsEmpty())
    {
         LOGD(LOG_TAG, "callback is null");
    }

    // We may have a connection error to report
    if (!ws->m_connection_error.empty() && std::string(*str).compare("onfail") == 0)
    {
        ws->callEventCallback(event_onfail, ws->m_connection_error);
        ws->m_connection_error.clear();
    }
} else {
    LOGE(LOG_TAG, "SetOnOpen(): invalid parameter type - value is not a function");
}

}

访问持久性功能时V8崩溃

1 个答案: