/* -*- 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_layers_DragMetrics_h
#define mozilla_layers_DragMetrics_h

#include "mozilla/layers/ScrollableLayerGuid.h"
#include "LayersTypes.h"
#include "mozilla/Maybe.h"

namespace IPC {
template <typename T>
struct ParamTraits;
}  // namespace IPC

namespace mozilla {

namespace layers {

class AsyncDragMetrics {
  friend struct IPC::ParamTraits<mozilla::layers::AsyncDragMetrics>;

 public:
  // IPC constructor
  AsyncDragMetrics()
      : mViewId(0),
        mPresShellId(0),
        mDragStartSequenceNumber(0),
        mScrollbarDragOffset(0) {}

  AsyncDragMetrics(const ScrollableLayerGuid::ViewID& aViewId,
                   uint32_t aPresShellId, uint64_t aDragStartSequenceNumber,
                   CSSCoord aScrollbarDragOffset, ScrollDirection aDirection)
      : mViewId(aViewId),
        mPresShellId(aPresShellId),
        mDragStartSequenceNumber(aDragStartSequenceNumber),
        mScrollbarDragOffset(aScrollbarDragOffset),
        mDirection(Some(aDirection)) {}

  ScrollableLayerGuid::ViewID mViewId;
  uint32_t mPresShellId;
  uint64_t mDragStartSequenceNumber;
  CSSCoord mScrollbarDragOffset;  // relative to the thumb's start offset
  Maybe<ScrollDirection> mDirection;
};

}  // namespace layers
}  // namespace mozilla

#endif