// 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 UI_COMPOSITOR_RECYCLABLE_COMPOSITOR_MAC_H_
#define UI_COMPOSITOR_RECYCLABLE_COMPOSITOR_MAC_H_

#include <list>
#include <memory>

#include "base/no_destructor.h"
#include "components/viz/common/surfaces/local_surface_id.h"
#include "components/viz/common/surfaces/parent_local_surface_id_allocator.h"
#include "ui/accelerated_widget_mac/accelerated_widget_mac.h"
#include "ui/compositor/compositor.h"
#include "ui/compositor/compositor_export.h"
#include "ui/compositor/compositor_observer.h"

namespace ui {

////////////////////////////////////////////////////////////////////////////////
// RecyclableCompositorMac
//
// A ui::Compositor and a gfx::AcceleratedWidget (and helper) that it draws
// into. This structure is used to efficiently recycle these structures across
// tabs (because creating a new ui::Compositor for each tab would be expensive
// in terms of time and resources).
class COMPOSITOR_EXPORT RecyclableCompositorMac
    : public ui::CompositorObserver {
 public:
  explicit RecyclableCompositorMac(ui::ContextFactory* context_factory);

  RecyclableCompositorMac(const RecyclableCompositorMac&) = delete;
  RecyclableCompositorMac& operator=(const RecyclableCompositorMac&) = delete;

  ~RecyclableCompositorMac() override;

  ui::Compositor* compositor() { return &compositor_; }
  ui::AcceleratedWidgetMac* widget() { return accelerated_widget_mac_.get(); }
  const gfx::Size pixel_size() const { return size_pixels_; }
  float scale_factor() const { return scale_factor_; }

  // Suspend will prevent the compositor from producing new frames. This should
  // be called to avoid creating spurious frames while changing state.
  // Compositors are created as suspended.
  void Suspend();
  void Unsuspend();

  // Update the compositor's surface information, if needed.
  void UpdateSurface(const gfx::Size& size_pixels,
                     float scale_factor,
                     const gfx::DisplayColorSpaces& display_color_spaces);

 private:
  // Invalidate the compositor's surface information.
  void InvalidateSurface();

  // ui::CompositorObserver implementation:
  void OnCompositingDidCommit(ui::Compositor* compositor) override;

  // The viz::ParentLocalSurfaceIdAllocator for the ui::Compositor dispenses
  // viz::LocalSurfaceIds that are renderered into by the ui::Compositor.
  viz::ParentLocalSurfaceIdAllocator local_surface_id_allocator_;
  gfx::Size size_pixels_;
  float scale_factor_ = 1.f;
  gfx::DisplayColorSpaces display_color_spaces_;

  std::unique_ptr<ui::AcceleratedWidgetMac> accelerated_widget_mac_;
  ui::Compositor compositor_;
  std::unique_ptr<ui::CompositorLock> compositor_suspended_lock_;
};

}  // namespace ui

#endif  // UI_COMPOSITOR_RECYCLABLE_COMPOSITOR_MAC_H_