Files
react-native/ReactCommon/react/renderer/core/EventEmitter.h
T
Andres Suarez 8bd3edec88 Update copyright headers from Facebook to Meta
Reviewed By: aaronabramov

Differential Revision: D33367752

fbshipit-source-id: 4ce94d184485e5ee0a62cf67ad2d3ba16e285c8f
2021-12-30 15:11:21 -08:00

106 lines
2.9 KiB
C++

/*
* Copyright (c) Meta Platforms, Inc. and affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/
#pragma once
#include <memory>
#include <mutex>
#include <folly/dynamic.h>
#include <react/renderer/core/EventDispatcher.h>
#include <react/renderer/core/EventPriority.h>
#include <react/renderer/core/EventTarget.h>
#include <react/renderer/core/ReactPrimitives.h>
namespace facebook {
namespace react {
class EventEmitter;
using SharedEventEmitter = std::shared_ptr<const EventEmitter>;
/*
* Base class for all particular typed event handlers.
* Stores a pointer to `EventTarget` identifying a particular component and
* a weak pointer to `EventDispatcher` which is responsible for delivering the
* event.
*/
class EventEmitter {
public:
using Shared = std::shared_ptr<EventEmitter const>;
static std::mutex &DispatchMutex();
static ValueFactory defaultPayloadFactory();
EventEmitter(
SharedEventTarget eventTarget,
Tag tag,
EventDispatcher::Weak eventDispatcher);
virtual ~EventEmitter() = default;
/*
* Enables/disables event emitter.
* Enabled event emitter retains a pointer to `eventTarget` strongly (as
* `std::shared_ptr`) whereas disabled one don't.
* Enabled/disabled state is also proxied to `eventTarget` where it indicates
* a possibility to extract JSI value from it.
* The enable state is additive; a number of `enable` calls should be equal to
* a number of `disable` calls to release the event target.
* `DispatchMutex` must be acquired before calling.
*/
void setEnabled(bool enabled) const;
protected:
#ifdef ANDROID
// We need this temporarily due to lack of Java-counterparts for particular
// subclasses.
public:
#endif
/*
* Initiates an event delivery process.
* Is used by particular subclasses only.
*/
void dispatchEvent(
const std::string &type,
const ValueFactory &payloadFactory =
EventEmitter::defaultPayloadFactory(),
EventPriority priority = EventPriority::AsynchronousBatched,
RawEvent::Category category = RawEvent::Category::Unspecified) const;
void dispatchEvent(
const std::string &type,
const folly::dynamic &payload,
EventPriority priority = EventPriority::AsynchronousBatched,
RawEvent::Category category = RawEvent::Category::Unspecified) const;
void dispatchUniqueEvent(
const std::string &type,
const folly::dynamic &payload) const;
void dispatchUniqueEvent(
const std::string &type,
const ValueFactory &payloadFactory =
EventEmitter::defaultPayloadFactory()) const;
private:
void toggleEventTargetOwnership_() const;
friend class UIManagerBinding;
mutable SharedEventTarget eventTarget_;
EventDispatcher::Weak eventDispatcher_;
mutable int enableCounter_{0};
mutable bool isEnabled_{false};
};
} // namespace react
} // namespace facebook