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// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "extensions/renderer/event_emitter.h"
#include <algorithm>
#include "gin/object_template_builder.h"
#include "gin/per_context_data.h"
namespace extensions {
gin::WrapperInfo EventEmitter::kWrapperInfo = {gin::kEmbedderNativeGin};
EventEmitter::EventEmitter(const binding::RunJSFunction& run_js,
const ListenersChangedMethod& listeners_changed)
: run_js_(run_js), listeners_changed_(listeners_changed) {}
EventEmitter::~EventEmitter() {}
gin::ObjectTemplateBuilder EventEmitter::GetObjectTemplateBuilder(
v8::Isolate* isolate) {
return Wrappable<EventEmitter>::GetObjectTemplateBuilder(isolate)
.SetMethod("addListener", &EventEmitter::AddListener)
.SetMethod("removeListener", &EventEmitter::RemoveListener)
.SetMethod("hasListener", &EventEmitter::HasListener)
.SetMethod("hasListeners", &EventEmitter::HasListeners)
// The following methods aren't part of the public API, but are used
// by our custom bindings and exposed on the public event object. :(
// TODO(devlin): Once we convert all custom bindings that use these,
// they can be removed.
.SetMethod("dispatch", &EventEmitter::Dispatch);
}
void EventEmitter::Fire(v8::Local<v8::Context> context,
std::vector<v8::Local<v8::Value>>* args) {
// We create a local copy of listeners_ since the array can be modified during
// handling.
std::vector<v8::Local<v8::Function>> listeners;
listeners.reserve(listeners_.size());
for (const auto& listener : listeners_)
listeners.push_back(listener.Get(context->GetIsolate()));
for (const auto& listener : listeners) {
v8::TryCatch try_catch(context->GetIsolate());
// SetVerbose() means the error will still get logged, which is what we
// want. We don't let it bubble up any further to prevent it from being
// surfaced in e.g. JS code that triggered the event.
try_catch.SetVerbose(true);
run_js_.Run(listener, context, args->size(), args->data());
}
}
void EventEmitter::AddListener(gin::Arguments* arguments) {
v8::Local<v8::Function> listener;
// TODO(devlin): For some reason, we don't throw an error when someone calls
// add/removeListener with no argument. We probably should. For now, keep
// the status quo, but we should revisit this.
if (!arguments->GetNext(&listener))
return;
v8::Local<v8::Object> holder;
CHECK(arguments->GetHolder(&holder));
CHECK(!holder.IsEmpty());
v8::Local<v8::Context> context = holder->CreationContext();
if (!gin::PerContextData::From(context))
return;
if (!HasListener(listener)) {
listeners_.push_back(
v8::Global<v8::Function>(arguments->isolate(), listener));
if (listeners_.size() == 1) {
listeners_changed_.Run(binding::EventListenersChanged::HAS_LISTENERS,
context);
}
}
}
void EventEmitter::RemoveListener(gin::Arguments* arguments) {
v8::Local<v8::Function> listener;
// See comment in AddListener().
if (!arguments->GetNext(&listener))
return;
auto iter = std::find(listeners_.begin(), listeners_.end(), listener);
if (iter != listeners_.end()) {
listeners_.erase(iter);
if (listeners_.empty()) {
v8::Local<v8::Object> holder;
CHECK(arguments->GetHolder(&holder));
CHECK(!holder.IsEmpty());
v8::Local<v8::Context> context = holder->CreationContext();
listeners_changed_.Run(binding::EventListenersChanged::NO_LISTENERS,
context);
}
}
}
bool EventEmitter::HasListener(v8::Local<v8::Function> listener) {
return std::find(listeners_.begin(), listeners_.end(), listener) !=
listeners_.end();
}
bool EventEmitter::HasListeners() {
return !listeners_.empty();
}
void EventEmitter::Dispatch(gin::Arguments* arguments) {
if (listeners_.empty())
return;
v8::HandleScope handle_scope(arguments->isolate());
v8::Local<v8::Context> context =
arguments->isolate()->GetCurrentContext();
std::vector<v8::Local<v8::Value>> v8_args;
if (arguments->Length() > 0) {
// Converting to v8::Values should never fail.
CHECK(arguments->GetRemaining(&v8_args));
}
Fire(context, &v8_args);
}
} // namespace extensions
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