components/viz/service/surfaces/surface_reference.h

// Copyright 2016 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_SERVICE_SURFACES_SURFACE_REFERENCE_H_
#define COMPONENTS_VIZ_SERVICE_SURFACES_SURFACE_REFERENCE_H_

#include <compare>
#include <string>

#include "base/hash/hash.h"
#include "components/viz/common/surfaces/surface_id.h"
#include "components/viz/service/viz_service_export.h"

namespace viz {

// Hold a reference from an embedding (parent) to embedded (child) surface.
class VIZ_SERVICE_EXPORT SurfaceReference {
 public:
  SurfaceReference();
  SurfaceReference(const SurfaceId& parent_id, const SurfaceId& child_id);
  SurfaceReference(const SurfaceReference& other);

  ~SurfaceReference();

  const SurfaceId& parent_id() const { return parent_id_; }
  const SurfaceId& child_id() const { return child_id_; }

  size_t hash() const {
    return base::HashInts(static_cast<uint64_t>(parent_id_.hash()),
                          static_cast<uint64_t>(child_id_.hash()));
  }

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

  std::string ToString() const;

 private:
  SurfaceId parent_id_;
  SurfaceId child_id_;
};

struct SurfaceReferenceHash {
  size_t operator()(const SurfaceReference& ref) const { return ref.hash(); }
};

VIZ_SERVICE_EXPORT std::ostream& operator<<(
    std::ostream& out,
    const SurfaceReference& surface_reference);

}  // namespace viz

#endif  // COMPONENTS_VIZ_SERVICE_SURFACES_SURFACE_REFERENCE_H_