electron/atom/browser/api/event_subscriber.cc

121 lines
4.1 KiB
C++

// Copyright (c) 2017 GitHub, Inc.
// Use of this source code is governed by the MIT license that can be
// found in the LICENSE file.
#include <string>
#include "atom/browser/api/event_subscriber.h"
#include "atom/common/native_mate_converters/callback.h"
namespace {
// A FunctionTemplate lifetime is bound to the v8 context, so it can be safely
// stored as a global here since there's only one for the main process.
v8::Global<v8::FunctionTemplate> g_cached_template;
struct JSHandlerData {
JSHandlerData(v8::Isolate* isolate,
mate::internal::EventSubscriberBase* subscriber)
: handle_(isolate, v8::External::New(isolate, this)),
subscriber_(subscriber) {
handle_.SetWeak(this, GC, v8::WeakCallbackType::kFinalizer);
}
static void GC(const v8::WeakCallbackInfo<JSHandlerData>& data) {
delete data.GetParameter();
}
v8::Global<v8::External> handle_;
mate::internal::EventSubscriberBase* subscriber_;
};
void InvokeCallback(const v8::FunctionCallbackInfo<v8::Value>& info) {
v8::Locker locker(info.GetIsolate());
v8::HandleScope handle_scope(info.GetIsolate());
v8::Local<v8::Context> context = info.GetIsolate()->GetCurrentContext();
v8::Context::Scope context_scope(context);
mate::Arguments args(info);
v8::Local<v8::Value> handler, event;
args.GetNext(&handler);
args.GetNext(&event);
DCHECK(handler->IsExternal());
DCHECK(event->IsString());
JSHandlerData* handler_data = static_cast<JSHandlerData*>(
v8::Local<v8::External>::Cast(handler)->Value());
handler_data->subscriber_->EventEmitted(mate::V8ToString(event), &args);
}
} // namespace
namespace mate {
namespace internal {
EventSubscriberBase::EventSubscriberBase(v8::Isolate* isolate,
v8::Local<v8::Object> emitter)
: isolate_(isolate), emitter_(isolate, emitter) {
if (g_cached_template.IsEmpty()) {
g_cached_template = v8::Global<v8::FunctionTemplate>(
isolate_, v8::FunctionTemplate::New(isolate_, InvokeCallback));
}
}
EventSubscriberBase::~EventSubscriberBase() {
if (!isolate_) {
return;
}
RemoveAllListeners();
emitter_.Reset();
DCHECK_EQ(js_handlers_.size(), 0u);
}
void EventSubscriberBase::On(const std::string& event_name) {
DCHECK(js_handlers_.find(event_name) == js_handlers_.end());
v8::Locker locker(isolate_);
v8::Isolate::Scope isolate_scope(isolate_);
v8::HandleScope handle_scope(isolate_);
auto fn_template = g_cached_template.Get(isolate_);
auto event = mate::StringToV8(isolate_, event_name);
auto js_handler_data = new JSHandlerData(isolate_, this);
v8::Local<v8::Value> fn = internal::BindFunctionWith(
isolate_, isolate_->GetCurrentContext(), fn_template->GetFunction(),
js_handler_data->handle_.Get(isolate_), event);
js_handlers_.insert(
std::make_pair(event_name, v8::Global<v8::Value>(isolate_, fn)));
internal::ValueVector converted_args = {event, fn};
internal::CallMethodWithArgs(isolate_, emitter_.Get(isolate_), "on",
&converted_args);
}
void EventSubscriberBase::Off(const std::string& event_name) {
v8::Locker locker(isolate_);
v8::Isolate::Scope isolate_scope(isolate_);
v8::HandleScope handle_scope(isolate_);
auto js_handler = js_handlers_.find(event_name);
DCHECK(js_handler != js_handlers_.end());
RemoveListener(js_handler);
}
void EventSubscriberBase::RemoveAllListeners() {
v8::Locker locker(isolate_);
v8::Isolate::Scope isolate_scope(isolate_);
v8::HandleScope handle_scope(isolate_);
while (!js_handlers_.empty()) {
RemoveListener(js_handlers_.begin());
}
}
std::map<std::string, v8::Global<v8::Value>>::iterator
EventSubscriberBase::RemoveListener(
std::map<std::string, v8::Global<v8::Value>>::iterator it) {
internal::ValueVector args = {StringToV8(isolate_, it->first),
it->second.Get(isolate_)};
internal::CallMethodWithArgs(
isolate_, v8::Local<v8::Object>::Cast(emitter_.Get(isolate_)),
"removeListener", &args);
it->second.Reset();
return js_handlers_.erase(it);
}
} // namespace internal
} // namespace mate