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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_dom_CoalescedInputData_h
#define mozilla_dom_CoalescedInputData_h
#include "mozilla/UniquePtr.h"
#include "mozilla/layers/ScrollableLayerGuid.h"
#include "nsRefreshObservers.h"
class nsRefreshDriver;
namespace mozilla::dom {
class BrowserChild;
template <class InputEventType>
class CoalescedInputData {
protected:
using ScrollableLayerGuid = mozilla::layers::ScrollableLayerGuid;
UniquePtr<InputEventType> mCoalescedInputEvent;
ScrollableLayerGuid mGuid;
uint64_t mInputBlockId = 0;
uint32_t mGeneration = 0;
void AdvanceGeneration() {
if (!IsEmpty()) {
mGeneration++;
}
}
public:
CoalescedInputData() = default;
void RetrieveDataFrom(CoalescedInputData& aSource) {
aSource.AdvanceGeneration();
AdvanceGeneration();
mCoalescedInputEvent = std::move(aSource.mCoalescedInputEvent);
mGuid = aSource.mGuid;
mInputBlockId = aSource.mInputBlockId;
}
bool IsEmpty() { return !mCoalescedInputEvent; }
bool CanCoalesce(const InputEventType& aEvent,
const ScrollableLayerGuid& aGuid,
const uint64_t& aInputBlockId);
UniquePtr<InputEventType> TakeCoalescedEvent() {
AdvanceGeneration();
return std::move(mCoalescedInputEvent);
}
ScrollableLayerGuid GetScrollableLayerGuid() { return mGuid; }
uint64_t GetInputBlockId() { return mInputBlockId; }
/**
* The generation number of the latest state stored by the instance.
* It'll be incremented when the coalesced event data is retrieved or taken.
* So, this is useful to avoid handling same coalesced events twice when
* a nested event loop may handle this.
* NOTE: You should compare the value only with `==` or `!=`. Do not use
* `<` nor `>` because the value may circulate to 0 from UINT32_MAX.
*/
[[nodiscard]] uint32_t Generation() const { return mGeneration; }
};
class CoalescedInputFlusher : public nsARefreshObserver {
public:
explicit CoalescedInputFlusher(BrowserChild* aBrowserChild);
virtual void WillRefresh(mozilla::TimeStamp aTime) override = 0;
NS_INLINE_DECL_REFCOUNTING(CoalescedInputFlusher, override)
void StartObserver();
void RemoveObserver();
/**
* Return a refresh driver which is proper one for BrowserChild.
* Note that this is not a getter of mRefreshDriver.
*/
[[nodiscard]] nsRefreshDriver* GetRefreshDriver();
protected:
virtual ~CoalescedInputFlusher();
BrowserChild* mBrowserChild;
// A refresh driver which this instance waits for the next refresh of.
RefPtr<nsRefreshDriver> mRefreshDriver;
};
} // namespace mozilla::dom
#endif // mozilla_dom_CoalescedInputData_h
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