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Re-use existing JS event emitters when creating JS side wrappers

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By not re-using JS event emitters, if a JS/C++ wrapper is created twice for
a `QObject` then any previously registered event handlers will be overwritten
and lost when the `QObject`'s `initNodeEventEmitter()` is called for a 2nd
time.
This commit is contained in:
Simon Edwards 2021-08-01 20:43:04 +02:00
parent faa6adcb23
commit 87e6531c65
2 changed files with 39 additions and 22 deletions
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10
src/cpp/include/nodegui/core/Events/eventwidget_macro.h
View File

@ -22,6 +22,14 @@
return env.Null(); \
} \
\
Napi::Value getNodeEventEmitter(const Napi::CallbackInfo& info) { \
Napi::Env env = info.Env(); \
if (this->instance->emitOnNode) { \
return this->instance->emitOnNode.Value(); \
} else { \
return env.Null(); \
} \
} \
Napi::Value subscribeToQtEvent(const Napi::CallbackInfo& info) { \
Napi::Env env = info.Env(); \
Napi::String eventString = info[0].As<Napi::String>(); \
@ -42,6 +50,8 @@
COMPONENT_WRAPPED_METHODS_EXPORT_DEFINE(WidgetWrapName) \
InstanceMethod("initNodeEventEmitter", \
&WidgetWrapName::initNodeEventEmitter), \
InstanceMethod("getNodeEventEmitter", \
&WidgetWrapName::getNodeEventEmitter), \
InstanceMethod("subscribeToQtEvent", \
&WidgetWrapName::subscribeToQtEvent), \
InstanceMethod("unSubscribeToQtEvent", \

51
src/lib/core/EventWidget.ts
View File

@ -38,30 +38,37 @@ export abstract class EventWidget<Signals extends unknown> extends Component {
private _isEventProcessed = false;
constructor(native: NativeElement) {
super();
if (native.initNodeEventEmitter) {
this.emitter = new EventEmitter();
this.emitter.emit = wrapWithActivateUvLoop(this.emitter.emit.bind(this.emitter));
const logExceptions = (event: string | symbol, ...args: any[]): boolean => {
// Preserve the value of `_isQObjectEventProcessed` as we dispatch this event
// to JS land, and restore it afterwards. This lets us support recursive event
// dispatches on the same object.
const previousEventProcessed = this._isEventProcessed;
this._isEventProcessed = false;
try {
this.emitter.emit(event, ...args);
} catch (e) {
console.log(`An exception was thrown while dispatching an event of type '${event.toString()}':`);
console.log(e);
}
const returnCode = this._isEventProcessed;
this._isEventProcessed = previousEventProcessed;
return returnCode;
};
native.initNodeEventEmitter(logExceptions);
} else {
if (native.initNodeEventEmitter == null) {
throw new Error('initNodeEventEmitter not implemented on native side');
}
const preexistingEmitterFunc = native.getNodeEventEmitter();
if (preexistingEmitterFunc != null) {
this.emitter = preexistingEmitterFunc.emitter;
return;
}
this.emitter = new EventEmitter();
this.emitter.emit = wrapWithActivateUvLoop(this.emitter.emit.bind(this.emitter));
const logExceptions = (event: string | symbol, ...args: any[]): boolean => {
// Preserve the value of `_isQObjectEventProcessed` as we dispatch this event
// to JS land, and restore it afterwards. This lets us support recursive event
// dispatches on the same object.
const previousEventProcessed = this._isEventProcessed;
this._isEventProcessed = false;
try {
this.emitter.emit(event, ...args);
} catch (e) {
console.log(`An exception was thrown while dispatching an event of type '${event.toString()}':`);
console.log(e);
}
const returnCode = this._isEventProcessed;
this._isEventProcessed = previousEventProcessed;
return returnCode;
};
logExceptions.emitter = this.emitter;
native.initNodeEventEmitter(logExceptions);
addDefaultErrorHandler(native, this.emitter);
}