chromium/third_party/blink/renderer/modules/webgpu/gpu_external_texture.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 THIRD_PARTY_BLINK_RENDERER_MODULES_WEBGPU_GPU_EXTERNAL_TEXTURE_H_
#define THIRD_PARTY_BLINK_RENDERER_MODULES_WEBGPU_GPU_EXTERNAL_TEXTURE_H_

#include <atomic>

#include "base/task/single_thread_task_runner.h"
#include "media/base/video_frame.h"
#include "third_party/blink/renderer/modules/webgpu/dawn_object.h"
#include "third_party/blink/renderer/platform/bindings/script_wrappable.h"
#include "third_party/blink/renderer/platform/heap/collection_support/heap_hash_map.h"
#include "third_party/blink/renderer/platform/heap/collection_support/heap_hash_set.h"
#include "third_party/blink/renderer/platform/heap/garbage_collected.h"
#include "third_party/blink/renderer/platform/wtf/ref_counted.h"

namespace blink {

class ExceptionState;
class GPUExternalTexture;
class GPUExternalTextureDescriptor;
class WebGPUMailboxTexture;
class HTMLVideoElement;
class VideoFrame;

// GPUExternalTexture uses auto expiry mechanism
// (https://www.w3.org/TR/webgpu/#-automatic-expiry-task-source). The
// mechanism requires webgpu to expire GPUExternalTexture when current task
// scope finished by posting expiration task. The expired GPUExternalTexture
// is invalid to submit and needs to call importExternalTexture() to get the
// refreshed GPUExternalTexture object. In implementation side,
// importExternalTexture() also wraps GPUExternalTexture with underly video
// frames. It is possible that multiple importExternalTexture() call with the
// same source tries to wrap the same underly video frames. So a cache system
// has been integrated to avoid re-creating the GPUExternalTexture again and
// again with the same video frame. So importExternalTexture() tries to do:
// - Search cache to see any hit. if not, create a new GPUExternalTexture and
// insert it into cache.
// - Refresh the external texture to un-expire it.
// - Post a task to expire this external texture after finishing current task.
// More details refers to
// https://www.w3.org/TR/webgpu/#external-texture-creation
class ExternalTextureCache : public GarbageCollected<ExternalTextureCache> { … };

class GPUExternalTexture : public DawnObject<wgpu::ExternalTexture> { … };

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_MODULES_WEBGPU_GPU_EXTERNAL_TEXTURE_H_