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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 */
#ifndef mozilla_layers_FocusTarget_h
#define mozilla_layers_FocusTarget_h
#include <stdint.h> // for int32_t, uint32_t
#include "mozilla/DefineEnum.h" // for MOZ_DEFINE_ENUM
#include "mozilla/layers/ScrollableLayerGuid.h" // for ViewID
#include "mozilla/Variant.h" // for Variant
#include "mozilla/Maybe.h" // for Maybe
namespace mozilla {
class PresShell;
namespace layers {
* This class is used for communicating information about the currently focused
* element of a document and the scrollable frames to use when keyboard
* scrolling it. It is created on the main thread at paint-time, but is then
* passed over IPC to the compositor/APZ code.
class FocusTarget final {
struct ScrollTargets {
ScrollableLayerGuid::ViewID mHorizontal;
ScrollableLayerGuid::ViewID mVertical;
bool operator==(const ScrollTargets& aRhs) const {
return (mHorizontal == aRhs.mHorizontal && mVertical == aRhs.mVertical);
// We need this to represent the case where mData has no focus target data
// because we can't have an empty variant
struct NoFocusTarget {
bool operator==(const NoFocusTarget& aRhs) const { return true; }
* Construct a focus target for the specified top level PresShell
FocusTarget(PresShell* aRootPresShell, uint64_t aFocusSequenceNumber);
bool operator==(const FocusTarget& aRhs) const;
const char* Type() const;
// The content sequence number recorded at the time of this class's creation
uint64_t mSequenceNumber;
// Whether there are keydown, keypress, or keyup event listeners
// in the event target chain of the focused element
bool mFocusHasKeyEventListeners;
mozilla::Variant<LayersId, ScrollTargets, NoFocusTarget> mData;
} // namespace layers
} // namespace mozilla
#endif // mozilla_layers_FocusTarget_h