components/viz/common/surfaces/surface_range.h

// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_VIZ_COMMON_SURFACES_SURFACE_RANGE_H_
#define COMPONENTS_VIZ_COMMON_SURFACES_SURFACE_RANGE_H_

#include <compare>
#include <optional>
#include <string>

#include "components/viz/common/surfaces/surface_id.h"
#include "components/viz/common/viz_common_export.h"
#include "mojo/public/cpp/bindings/struct_traits.h"

namespace viz {

namespace mojom {
class SurfaceRangeDataView;
}

// SurfaceRange consists of two SurfaceIds representing a range of surfaces
// [start,end] ordered by SurfaceId where |start| is an optional surface
// which acts like a "fallback" surface in case it exists.
class VIZ_COMMON_EXPORT SurfaceRange {
 public:
  SurfaceRange();

  SurfaceRange(const std::optional<SurfaceId>& start, const SurfaceId& end);

  explicit SurfaceRange(const SurfaceId& surface_id);

  SurfaceRange(const SurfaceRange& other);
  SurfaceRange& operator=(const SurfaceRange& other);

  friend std::strong_ordering operator<=>(const SurfaceRange&,
                                          const SurfaceRange&) = default;

  // Check if |surface_id| falls within |this| SurfaceRange but is neither the
  // start nor end of the range. The FrameSinkId of |surface_id| must match
  // either the start or end of the range.
  bool IsInRangeExclusive(const SurfaceId& surface_id) const;

  // Check if |surface_id| falls within |this| SurfaceRange inclusive of the
  // start and end of the range. The FrameSinkId of |surface_id| must match
  // either the start or end of the range.
  bool IsInRangeInclusive(const SurfaceId& surface_id) const;

  // Returns whether the start and end of the range have differing FrameSinkIds.
  bool HasDifferentFrameSinkIds() const;

  // Returns whether the start and end of the range have different embed tokens.
  bool HasDifferentEmbedTokens() const;

  bool IsValid() const;

  const std::optional<SurfaceId>& start() const { return start_; }

  const SurfaceId& end() const { return end_; }

  std::string ToString() const;

 private:
  friend struct mojo::StructTraits<mojom::SurfaceRangeDataView, SurfaceRange>;

  std::optional<SurfaceId> start_;
  SurfaceId end_;
};

VIZ_COMMON_EXPORT std::ostream& operator<<(std::ostream& out,
                                           const SurfaceRange& surface_range);

}  // namespace viz

#endif  // COMPONENTS_VIZ_COMMON_SURFACES_SURFACE_RANGE_H_