components/viz/service/display/display_resource_provider_skia.h

// Copyright 2021 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_DISPLAY_DISPLAY_RESOURCE_PROVIDER_SKIA_H_
#define COMPONENTS_VIZ_SERVICE_DISPLAY_DISPLAY_RESOURCE_PROVIDER_SKIA_H_

#include <utility>
#include <vector>

#include "base/memory/raw_ptr.h"
#include "components/viz/service/display/display_resource_provider.h"
#include "components/viz/service/display/external_use_client.h"
#include "components/viz/service/viz_service_export.h"

namespace viz {

// DisplayResourceProvider implementation used with SkiaRenderer.
class VIZ_SERVICE_EXPORT DisplayResourceProviderSkia
    : public DisplayResourceProvider {
 public:
  DisplayResourceProviderSkia();
  ~DisplayResourceProviderSkia() override;

  // Same as ScopedReadLockSharedImage, but will release |image_context| if
  // already was created, making sure resource isn't locked by compositor.
  class VIZ_SERVICE_EXPORT ScopedExclusiveReadLockSharedImage
      : public ScopedReadLockSharedImage {
   public:
    ScopedExclusiveReadLockSharedImage(
        DisplayResourceProviderSkia* resource_provider,
        ResourceId resource_id);
    ~ScopedExclusiveReadLockSharedImage();
    ScopedExclusiveReadLockSharedImage(
        ScopedExclusiveReadLockSharedImage&& other);
  };

  // Maintains set of resources locked for external use by SkiaRenderer.
  class VIZ_SERVICE_EXPORT LockSetForExternalUse {
   public:
    // There should be at most one instance of this class per
    // |resource_provider|. Both |resource_provider| and |client| outlive this
    // class.
    LockSetForExternalUse(DisplayResourceProviderSkia* resource_provider,
                          ExternalUseClient* client);
    ~LockSetForExternalUse();

    LockSetForExternalUse(const LockSetForExternalUse&) = delete;
    LockSetForExternalUse& operator=(const LockSetForExternalUse& other) =
        delete;

    // Lock a resource for external use. The return value was created by
    // |client| at some point in the past. The SkImage color space will be set
    // to |override_color_space| if non-nullptr, otherwise it will be set to the
    // resource's color space. If |is_video_plane| is true, the image color
    // space will be set to nullptr (to avoid LOG spam).
    ExternalUseClient::ImageContext* LockResource(
        ResourceId resource_id,
        bool maybe_concurrent_reads,
        bool raw_draw_if_possible = false);

    // Unlock all locked resources with a |sync_token|.  The |sync_token| should
    // be waited on before reusing the resource's backing to ensure that any
    // external use of it is completed. This |sync_token| should have been
    // verified.  All resources must be unlocked before destroying this class.
    void UnlockResources(const gpu::SyncToken& sync_token);

   private:
    const raw_ptr<DisplayResourceProviderSkia, DanglingUntriaged>
        resource_provider_;
    std::vector<std::pair<ResourceId, ChildResource*>> resources_;
  };

  // Sets the current read fence. If a resource is locked for read
  // and has read fences enabled, the resource will not allow writes
  // until this fence has passed. This is used if a client uses
  // TransferableResource::SynchronizationType::kGpuCommandsCompleted.
  void SetGpuCommandsCompletedFence(ResourceFence* fence) {
    current_gpu_commands_completed_fence_ = fence;
  }
  // Sets the current release fence. If a client uses
  // TransferableResource::SynchronizationType::kReleaseFence, resources must be
  // returned only after a release fence is stored in this resource fence.
  // Returned only when gpu commands and the gpu fence are submitted.
  void SetReleaseFence(ResourceFence* fence) { current_release_fence_ = fence; }

 private:
  // DisplayResourceProvider overrides:
  std::vector<ReturnedResource> DeleteAndReturnUnusedResourcesToChildImpl(
      Child& child_info,
      DeleteStyle style,
      const std::vector<ResourceId>& unused) override;

  // Used to release resources held by an external consumer.
  raw_ptr<ExternalUseClient> external_use_client_ = nullptr;

  scoped_refptr<ResourceFence> current_gpu_commands_completed_fence_;
  scoped_refptr<ResourceFence> current_release_fence_;
};

}  // namespace viz

#endif  // COMPONENTS_VIZ_SERVICE_DISPLAY_DISPLAY_RESOURCE_PROVIDER_SKIA_H_