react-native/ReactCommon/fabric/events/EventEmitter.cpp

85 lines
1.9 KiB
C++

/**
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/
#include "EventEmitter.h"
#include <folly/dynamic.h>
#include "RawEvent.h"
namespace facebook {
namespace react {
// TODO(T29874519): Get rid of "top" prefix once and for all.
/*
* Capitalizes the first letter of the event type and adds "top" prefix
* (e.g. "layout" becames "topLayout").
*/
static std::string normalizeEventType(const std::string &type) {
auto prefixedType = type;
prefixedType[0] = toupper(prefixedType[0]);
prefixedType.insert(0, "top");
return prefixedType;
}
std::recursive_mutex &EventEmitter::DispatchMutex() {
static std::recursive_mutex mutex;
return mutex;
}
EventEmitter::EventEmitter(
SharedEventTarget eventTarget,
Tag tag,
WeakEventDispatcher eventDispatcher
):
eventTarget_(std::move(eventTarget)),
tag_(tag),
eventDispatcher_(std::move(eventDispatcher)) {}
void EventEmitter::dispatchEvent(
const std::string &type,
const folly::dynamic &payload,
const EventPriority &priority
) const {
auto eventDispatcher = eventDispatcher_.lock();
if (!eventDispatcher) {
return;
}
// Mixing `target` into `payload`.
assert(payload.isObject());
folly::dynamic extendedPayload = folly::dynamic::object("target", tag_);
extendedPayload.merge_patch(payload);
eventDispatcher->dispatchEvent(
RawEvent(
normalizeEventType(type),
extendedPayload,
eventTarget_
),
priority
);
}
void EventEmitter::setEnabled(bool enabled) const {
bool alreadyEnabled = eventTarget_ != nullptr;
if (enabled == alreadyEnabled) {
return;
}
if (!enabled) {
eventTarget_.reset();
}
}
bool EventEmitter::getEnabled() const {
return eventTarget_ != nullptr;
}
} // namespace react
} // namespace facebook