components/viz/service/display_embedder/skia_render_copy_results.cc - chromium/src - Git at Google

 // 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.

 #include "components/viz/service/display_embedder/skia_render_copy_results.h"

 #include <memory>
 #include <utility>

 #include "base/memory/ptr_util.h"
 #include "components/viz/common/frame_sinks/copy_output_result.h"
 #include "components/viz/service/display_embedder/skia_output_surface_impl_on_gpu.h"
 #include "third_party/libyuv/include/libyuv/planar_functions.h"
 #include "third_party/skia/include/core/SkPixelRef.h"

 namespace viz {

 AsyncReadResultLock::AsyncReadResultLock() = default;
 AsyncReadResultLock::~AsyncReadResultLock() = default;

 AsyncReadResultHelper::AsyncReadResultHelper(
     SkiaOutputSurfaceImplOnGpu* impl_on_gpu,
     std::unique_ptr<const SkSurface::AsyncReadResult> result)
     : lock_(impl_on_gpu->GetAsyncReadResultLock()),
       impl_on_gpu_(impl_on_gpu),
       result_(std::move(result)) {
   base::AutoLock auto_lock(lock());
   impl_on_gpu_->AddAsyncReadResultHelperWithLock(this);
 }

 AsyncReadResultHelper::~AsyncReadResultHelper() {
   base::AutoLock auto_lock(lock());
   if (impl_on_gpu_) {
     impl_on_gpu_->RemoveAsyncReadResultHelperWithLock(this);
   }
 }

 base::Lock& AsyncReadResultHelper::lock() const {
   return lock_->lock();
 }

 void AsyncReadResultHelper::reset() {
   AssertLockAcquired();
   impl_on_gpu_ = nullptr;
   result_.reset();
 }

 const SkSurface::AsyncReadResult* AsyncReadResultHelper::operator->() const {
   AssertLockAcquired();
   return result_.get();
 }

 AsyncReadResultHelper::operator bool() const {
   AssertLockAcquired();
   return !!result_;
 }

 void AsyncReadResultHelper::AssertLockAcquired() const {
   if (lock_)
     lock().AssertAcquired();
 }

 ReadPixelsContext::ReadPixelsContext(
     std::unique_ptr<CopyOutputRequest> request,
     const gfx::Rect& result_rect,
     const gfx::ColorSpace& color_space,
     base::WeakPtr<SkiaOutputSurfaceImplOnGpu> impl_on_gpu)
     : request(std::move(request)),
       result_rect(result_rect),
       color_space(color_space),
       impl_on_gpu(impl_on_gpu) {}

 ReadPixelsContext::~ReadPixelsContext() = default;

 CopyOutputResultSkiaRGBA::CopyOutputResultSkiaRGBA(
     SkiaOutputSurfaceImplOnGpu* impl,
     const gfx::Rect& rect,
     std::unique_ptr<const SkSurface::AsyncReadResult> result,
     const gfx::ColorSpace& color_space)
     : CopyOutputResult(Format::RGBA,
                        Destination::kSystemMemory,
                        rect,
                        /*needs_lock_for_bitmap=*/true),
       result_(impl, std::move(result)),
       color_space_(color_space.ToSkColorSpace()) {}

 CopyOutputResultSkiaRGBA::~CopyOutputResultSkiaRGBA() {
   // cached_bitmap()->pixelRef() should not be used after
   // CopyOutputResultSkiaRGBA is released.
   DCHECK(!cached_bitmap()->pixelRef() || cached_bitmap()->pixelRef()->unique());
 }

 // static
 void CopyOutputResultSkiaRGBA::OnReadbackDone(
     void* c,
     std::unique_ptr<const SkSurface::AsyncReadResult> async_result) {
   auto context = base::WrapUnique(static_cast<ReadPixelsContext*>(c));

   // This will automatically send an empty result.
   auto* impl_on_gpu = context->impl_on_gpu.get();
   if (!impl_on_gpu)
     return;

   impl_on_gpu->ReadbackDone();

   // This will automatically send an empty result.
   if (!async_result)
     return;

   auto result = std::make_unique<CopyOutputResultSkiaRGBA>(
       impl_on_gpu, context->result_rect, std::move(async_result),
       context->color_space);
   context->request->SendResult(std::move(result));
 }

 const SkBitmap& CopyOutputResultSkiaRGBA::AsSkBitmap() const {
   if (!result_) {
     // The |result_| has been reset, the cached_bitmap() should be reset too.
     *cached_bitmap() = SkBitmap();
   } else if (!bitmap_created_) {
     const auto* data = result_->data(0);
     auto row_bytes = result_->rowBytes(0);

     // TODO(https://bugs.chromium.org/p/skia/issues/detail?id=14389):
     // BGRA is not supported on iOS, so explicitly request RGBA here. This
     // should not prevent readback, however, so once that is fixed, this code
     // could be removed.
     auto info =
 #if BUILDFLAG(IS_IOS)
         SkImageInfo::Make(size().width(), size().height(),
                           kRGBA_8888_SkColorType, kPremul_SkAlphaType,
                           color_space_);
 #else
         SkImageInfo::MakeN32Premul(size().width(), size().height(),
                                    color_space_);
 #endif  // BUILDFLAG(IS_IOS)

     SkBitmap bitmap;
     bitmap.installPixels(info, const_cast<void*>(data), row_bytes);

     *cached_bitmap() = std::move(bitmap);
     bitmap_created_ = true;
   }

   return CopyOutputResult::AsSkBitmap();
 }

 bool CopyOutputResultSkiaRGBA::LockSkBitmap() const {
   result_.lock().Acquire();
   if (!result_) {
     result_.lock().Release();
     return false;
   }
   return true;
 }

 void CopyOutputResultSkiaRGBA::UnlockSkBitmap() const {
   result_.lock().AssertAcquired();
   result_.lock().Release();
 }

 ReadbackContextTexture::ReadbackContextTexture(
     base::WeakPtr<SkiaOutputSurfaceImplOnGpu> impl_on_gpu,
     std::unique_ptr<CopyOutputRequest> request,
     const gfx::Rect& result_rect,
     const gpu::Mailbox& mailbox,
     const gfx::ColorSpace& color_space)
     : impl_on_gpu_(impl_on_gpu),
       request_(std::move(request)),
       result_rect_(result_rect),
       mailbox_(mailbox),
       color_space_(color_space) {}

 ReadbackContextTexture::~ReadbackContextTexture() = default;

 void ReadbackContextTexture::OnMailboxReady(GrGpuFinishedContext c) {
   auto context = base::WrapUnique(static_cast<ReadbackContextTexture*>(c));
   context->OnMailboxReadyInternal();
   // `context` is destroyed when this goes out of scope.
 }

 void ReadbackContextTexture::OnMailboxReadyInternal() {
   DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);

   if (impl_on_gpu_) {
     impl_on_gpu_->ReadbackDone();
   }

   request_->SendResult(std::make_unique<CopyOutputSharedImageResult>(
       request_->result_format(), result_rect_, mailbox_, color_space_,
       "OnMailboxReadyInternal", ReleaseCallback()));
 }

 CopyOutputResultSkiaYUV::CopyOutputResultSkiaYUV(
     SkiaOutputSurfaceImplOnGpu* impl,
     const gfx::Rect& rect,
     std::unique_ptr<const SkSurface::AsyncReadResult> result)
     : CopyOutputResult(Format::I420_PLANES,
                        Destination::kSystemMemory,
                        rect,
                        /*needs_lock_for_bitmap=*/false),
       result_(impl, std::move(result)) {
 #if DCHECK_IS_ON()
   base::AutoLock auto_lock(result_.lock());
   DCHECK_EQ(3, result_->count());
   DCHECK_EQ(0, size().width() % 2);
   DCHECK_EQ(0, size().height() % 2);
 #endif
 }

 CopyOutputResultSkiaYUV::~CopyOutputResultSkiaYUV() = default;

 // static
 void CopyOutputResultSkiaYUV::OnReadbackDone(
     void* c,
     std::unique_ptr<const SkSurface::AsyncReadResult> async_result) {
   auto context = base::WrapUnique(static_cast<ReadPixelsContext*>(c));
   auto* impl_on_gpu = context->impl_on_gpu.get();

   // This will automatically send an empty result.
   if (!impl_on_gpu)
     return;

   impl_on_gpu->ReadbackDone();

   // This will automatically send an empty result.
   if (!async_result)
     return;

   auto result = std::make_unique<CopyOutputResultSkiaYUV>(
       impl_on_gpu, context->result_rect, std::move(async_result));
   context->request->SendResult(std::move(result));
 }

 // CopyOutputResult implementation:
 bool CopyOutputResultSkiaYUV::ReadI420Planes(base::span<uint8_t> y_out,
                                              int y_out_stride,
                                              base::span<uint8_t> u_out,
                                              int u_out_stride,
                                              base::span<uint8_t> v_out,
                                              int v_out_stride) const {
   // Hold the lock so the AsyncReadResultHelper will not be reset during
   // pixel data reading.
   base::AutoLock auto_lock(result_.lock());

   // The |result_| has been reset.
   if (!result_) {
     return false;
   }

   auto* data0 = static_cast<const uint8_t*>(result_->data(0));
   auto* data1 = static_cast<const uint8_t*>(result_->data(1));
   auto* data2 = static_cast<const uint8_t*>(result_->data(2));
   // TODO(crbug.com/384959115): Verify span size before calling into libyuv.
   libyuv::CopyPlane(data0, result_->rowBytes(0), y_out.data(), y_out_stride,
                     width(0), height(0));
   libyuv::CopyPlane(data1, result_->rowBytes(1), u_out.data(), u_out_stride,
                     width(1), height(1));
   libyuv::CopyPlane(data2, result_->rowBytes(2), v_out.data(), v_out_stride,
                     width(2), height(2));
   return true;
 }

 NV12PlanesReadbackContext::NV12PlanesReadbackContext(
     base::WeakPtr<SkiaOutputSurfaceImplOnGpu> impl_on_gpu,
     std::unique_ptr<CopyOutputRequest> request,
     const gfx::Rect& result_rect)
     : impl_on_gpu_(impl_on_gpu),
       request_(std::move(request)),
       result_rect_(result_rect) {}
 NV12PlanesReadbackContext::~NV12PlanesReadbackContext() = default;

 void NV12PlanesReadbackContext::PlaneReadbackDone(
     int plane_index,
     std::unique_ptr<const SkSurface::AsyncReadResult> async_result) {
   DCHECK_LT(plane_index, 2) << "NV12 readback requests at most 2 planes!";

   if (!impl_on_gpu_) {
     // We could not identify the impl_on_gpu, which means there's nothing else
     // we can do here (everything should already be cleaned up).
     return;
   }

   impl_on_gpu_->ReadbackDone();

   // Mark plane readback as completed and store results in the readback context:
   outstanding_reads_--;
   plane_results_[plane_index] = std::move(async_result);

   // Check if all planes have finished readback, send the result and clean up
   // the readback context if so:
   if (outstanding_reads_ == 0) {
     auto result = std::make_unique<CopyOutputResultSkiaNV12>(
         impl_on_gpu_.get(), result_rect_, std::move(plane_results_));

     request_->SendResult(std::move(result));
   }
 }

 NV12PlanePixelReadContext::NV12PlanePixelReadContext(
     scoped_refptr<NV12PlanesReadbackContext> nv12_planes_readback,
     int plane_index)
     : nv12_planes_readback(std::move(nv12_planes_readback)),
       plane_index(plane_index) {}
 NV12PlanePixelReadContext::~NV12PlanePixelReadContext() = default;

 CopyOutputResultSkiaNV12::CopyOutputResultSkiaNV12(
     SkiaOutputSurfaceImplOnGpu* impl,
     const gfx::Rect& rect,
     std::array<std::unique_ptr<const SkImage::AsyncReadResult>, 2>
         async_read_results)
     : CopyOutputResult(Format::I420_PLANES,
                        Destination::kSystemMemory,
                        rect,
                        /*needs_lock_for_bitmap=*/false) {
   DCHECK_EQ(0, size().width() % 2);
   DCHECK_EQ(0, size().height() % 2);

   for (auto& async_read_result : async_read_results) {
     plane_readback_results_.push_back(std::make_unique<AsyncReadResultHelper>(
         impl, std::move(async_read_result)));
   }
 }

 CopyOutputResultSkiaNV12::~CopyOutputResultSkiaNV12() = default;

 bool CopyOutputResultSkiaNV12::ReadNV12Planes(base::span<uint8_t> y_out,
                                               int y_out_stride,
                                               base::span<uint8_t> uv_out,
                                               int uv_out_stride) const {
   const auto plane_pointer = [y_out, uv_out](int plane_number) {
     return plane_number == 0 ? y_out.data() : uv_out.data();
   };

   const auto plane_stride = [y_out_stride, uv_out_stride](int plane_number) {
     return plane_number == 0 ? y_out_stride : uv_out_stride;
   };

   for (size_t i = 0; i < kNV12MaxPlanes; ++i) {
     // The ptr to the helper is not set, which means that readback for this
     // plane has failed. Return failure, partial results are not useful.
     if (!plane_readback_results_[i]) {
       return false;
     }

     const AsyncReadResultHelper& result = *plane_readback_results_[i].get();

     // Hold the lock so the AsyncReadResultHelper will not be reset during
     // pixel data reading.
     base::AutoLock auto_lock(result.lock());
     DCHECK_EQ(1, result->count());

     // The |result| has been reset.
     if (!result) {
       return false;
     }

     // TODO(crbug.com/384959115): Verify span size before calling into libyuv.
     auto* data = static_cast<const uint8_t*>(result->data(0));
     libyuv::CopyPlane(data, result->rowBytes(0), plane_pointer(i),
                       plane_stride(i), width(i), height(i));
   }

   return true;
 }

 // static
 void CopyOutputResultSkiaNV12::OnNV12PlaneReadbackDone(
     void* c,
     std::unique_ptr<const SkSurface::AsyncReadResult> async_result) {
   auto context = base::WrapUnique(static_cast<NV12PlanePixelReadContext*>(c));

   context->nv12_planes_readback->PlaneReadbackDone(context->plane_index,
                                                    std::move(async_result));
 }

 }  // namespace viz
	// 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.

	#include "components/viz/service/display_embedder/skia_render_copy_results.h"

	#include <memory>
	#include <utility>

	#include "base/memory/ptr_util.h"
	#include "components/viz/common/frame_sinks/copy_output_result.h"
	#include "components/viz/service/display_embedder/skia_output_surface_impl_on_gpu.h"
	#include "third_party/libyuv/include/libyuv/planar_functions.h"
	#include "third_party/skia/include/core/SkPixelRef.h"

	namespace viz {

	AsyncReadResultLock::AsyncReadResultLock() = default;
	AsyncReadResultLock::~AsyncReadResultLock() = default;

	AsyncReadResultHelper::AsyncReadResultHelper(
	SkiaOutputSurfaceImplOnGpu* impl_on_gpu,
	std::unique_ptr<const SkSurface::AsyncReadResult> result)
	: lock_(impl_on_gpu->GetAsyncReadResultLock()),
	impl_on_gpu_(impl_on_gpu),
	result_(std::move(result)) {
	base::AutoLock auto_lock(lock());
	impl_on_gpu_->AddAsyncReadResultHelperWithLock(this);
	}

	AsyncReadResultHelper::~AsyncReadResultHelper() {
	base::AutoLock auto_lock(lock());
	if (impl_on_gpu_) {
	impl_on_gpu_->RemoveAsyncReadResultHelperWithLock(this);
	}
	}

	base::Lock& AsyncReadResultHelper::lock() const {
	return lock_->lock();
	}

	void AsyncReadResultHelper::reset() {
	AssertLockAcquired();
	impl_on_gpu_ = nullptr;
	result_.reset();
	}

	const SkSurface::AsyncReadResult* AsyncReadResultHelper::operator->() const {
	AssertLockAcquired();
	return result_.get();
	}

	AsyncReadResultHelper::operator bool() const {
	AssertLockAcquired();
	return !!result_;
	}

	void AsyncReadResultHelper::AssertLockAcquired() const {
	if (lock_)
	lock().AssertAcquired();
	}

	ReadPixelsContext::ReadPixelsContext(
	std::unique_ptr<CopyOutputRequest> request,
	const gfx::Rect& result_rect,
	const gfx::ColorSpace& color_space,
	base::WeakPtr<SkiaOutputSurfaceImplOnGpu> impl_on_gpu)
	: request(std::move(request)),
	result_rect(result_rect),
	color_space(color_space),
	impl_on_gpu(impl_on_gpu) {}

	ReadPixelsContext::~ReadPixelsContext() = default;

	CopyOutputResultSkiaRGBA::CopyOutputResultSkiaRGBA(
	SkiaOutputSurfaceImplOnGpu* impl,
	const gfx::Rect& rect,
	std::unique_ptr<const SkSurface::AsyncReadResult> result,
	const gfx::ColorSpace& color_space)
	: CopyOutputResult(Format::RGBA,
	Destination::kSystemMemory,
	rect,
	/needs_lock_for_bitmap=/true),
	result_(impl, std::move(result)),
	color_space_(color_space.ToSkColorSpace()) {}

	CopyOutputResultSkiaRGBA::~CopyOutputResultSkiaRGBA() {
	// cached_bitmap()->pixelRef() should not be used after
	// CopyOutputResultSkiaRGBA is released.
	DCHECK(!cached_bitmap()->pixelRef() \|\| cached_bitmap()->pixelRef()->unique());
	}

	// static
	void CopyOutputResultSkiaRGBA::OnReadbackDone(
	void* c,
	std::unique_ptr<const SkSurface::AsyncReadResult> async_result) {
	auto context = base::WrapUnique(static_cast<ReadPixelsContext*>(c));

	// This will automatically send an empty result.
	auto* impl_on_gpu = context->impl_on_gpu.get();
	if (!impl_on_gpu)
	return;

	impl_on_gpu->ReadbackDone();

	// This will automatically send an empty result.
	if (!async_result)
	return;

	auto result = std::make_unique<CopyOutputResultSkiaRGBA>(
	impl_on_gpu, context->result_rect, std::move(async_result),
	context->color_space);
	context->request->SendResult(std::move(result));
	}

	const SkBitmap& CopyOutputResultSkiaRGBA::AsSkBitmap() const {
	if (!result_) {
	// The \|result_\| has been reset, the cached_bitmap() should be reset too.
	*cached_bitmap() = SkBitmap();
	} else if (!bitmap_created_) {
	const auto* data = result_->data(0);
	auto row_bytes = result_->rowBytes(0);

	// TODO(https://bugs.chromium.org/p/skia/issues/detail?id=14389):
	// BGRA is not supported on iOS, so explicitly request RGBA here. This
	// should not prevent readback, however, so once that is fixed, this code
	// could be removed.
	auto info =
	#if BUILDFLAG(IS_IOS)
	SkImageInfo::Make(size().width(), size().height(),
	kRGBA_8888_SkColorType, kPremul_SkAlphaType,
	color_space_);
	#else
	SkImageInfo::MakeN32Premul(size().width(), size().height(),
	color_space_);
	#endif // BUILDFLAG(IS_IOS)

	SkBitmap bitmap;
	bitmap.installPixels(info, const_cast<void*>(data), row_bytes);

	*cached_bitmap() = std::move(bitmap);
	bitmap_created_ = true;
	}

	return CopyOutputResult::AsSkBitmap();
	}

	bool CopyOutputResultSkiaRGBA::LockSkBitmap() const {
	result_.lock().Acquire();
	if (!result_) {
	result_.lock().Release();
	return false;
	}
	return true;
	}

	void CopyOutputResultSkiaRGBA::UnlockSkBitmap() const {
	result_.lock().AssertAcquired();
	result_.lock().Release();
	}

	ReadbackContextTexture::ReadbackContextTexture(
	base::WeakPtr<SkiaOutputSurfaceImplOnGpu> impl_on_gpu,
	std::unique_ptr<CopyOutputRequest> request,
	const gfx::Rect& result_rect,
	const gpu::Mailbox& mailbox,
	const gfx::ColorSpace& color_space)
	: impl_on_gpu_(impl_on_gpu),
	request_(std::move(request)),
	result_rect_(result_rect),
	mailbox_(mailbox),
	color_space_(color_space) {}

	ReadbackContextTexture::~ReadbackContextTexture() = default;

	void ReadbackContextTexture::OnMailboxReady(GrGpuFinishedContext c) {
	auto context = base::WrapUnique(static_cast<ReadbackContextTexture*>(c));
	context->OnMailboxReadyInternal();
	// `context` is destroyed when this goes out of scope.
	}

	void ReadbackContextTexture::OnMailboxReadyInternal() {
	DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);

	if (impl_on_gpu_) {
	impl_on_gpu_->ReadbackDone();
	}

	request_->SendResult(std::make_unique<CopyOutputSharedImageResult>(
	request_->result_format(), result_rect_, mailbox_, color_space_,
	"OnMailboxReadyInternal", ReleaseCallback()));
	}

	CopyOutputResultSkiaYUV::CopyOutputResultSkiaYUV(
	SkiaOutputSurfaceImplOnGpu* impl,
	const gfx::Rect& rect,
	std::unique_ptr<const SkSurface::AsyncReadResult> result)
	: CopyOutputResult(Format::I420_PLANES,
	Destination::kSystemMemory,
	rect,
	/needs_lock_for_bitmap=/false),
	result_(impl, std::move(result)) {
	#if DCHECK_IS_ON()
	base::AutoLock auto_lock(result_.lock());
	DCHECK_EQ(3, result_->count());
	DCHECK_EQ(0, size().width() % 2);
	DCHECK_EQ(0, size().height() % 2);
	#endif
	}

	CopyOutputResultSkiaYUV::~CopyOutputResultSkiaYUV() = default;

	// static
	void CopyOutputResultSkiaYUV::OnReadbackDone(
	void* c,
	std::unique_ptr<const SkSurface::AsyncReadResult> async_result) {
	auto context = base::WrapUnique(static_cast<ReadPixelsContext*>(c));
	auto* impl_on_gpu = context->impl_on_gpu.get();

	// This will automatically send an empty result.
	if (!impl_on_gpu)
	return;

	impl_on_gpu->ReadbackDone();

	// This will automatically send an empty result.
	if (!async_result)
	return;

	auto result = std::make_unique<CopyOutputResultSkiaYUV>(
	impl_on_gpu, context->result_rect, std::move(async_result));
	context->request->SendResult(std::move(result));
	}

	// CopyOutputResult implementation:
	bool CopyOutputResultSkiaYUV::ReadI420Planes(base::span<uint8_t> y_out,
	int y_out_stride,
	base::span<uint8_t> u_out,
	int u_out_stride,
	base::span<uint8_t> v_out,
	int v_out_stride) const {
	// Hold the lock so the AsyncReadResultHelper will not be reset during
	// pixel data reading.
	base::AutoLock auto_lock(result_.lock());

	// The \|result_\| has been reset.
	if (!result_) {
	return false;
	}

	auto* data0 = static_cast<const uint8_t*>(result_->data(0));
	auto* data1 = static_cast<const uint8_t*>(result_->data(1));
	auto* data2 = static_cast<const uint8_t*>(result_->data(2));
	// TODO(crbug.com/384959115): Verify span size before calling into libyuv.
	libyuv::CopyPlane(data0, result_->rowBytes(0), y_out.data(), y_out_stride,
	width(0), height(0));
	libyuv::CopyPlane(data1, result_->rowBytes(1), u_out.data(), u_out_stride,
	width(1), height(1));
	libyuv::CopyPlane(data2, result_->rowBytes(2), v_out.data(), v_out_stride,
	width(2), height(2));
	return true;
	}

	NV12PlanesReadbackContext::NV12PlanesReadbackContext(
	base::WeakPtr<SkiaOutputSurfaceImplOnGpu> impl_on_gpu,
	std::unique_ptr<CopyOutputRequest> request,
	const gfx::Rect& result_rect)
	: impl_on_gpu_(impl_on_gpu),
	request_(std::move(request)),
	result_rect_(result_rect) {}
	NV12PlanesReadbackContext::~NV12PlanesReadbackContext() = default;

	void NV12PlanesReadbackContext::PlaneReadbackDone(
	int plane_index,
	std::unique_ptr<const SkSurface::AsyncReadResult> async_result) {
	DCHECK_LT(plane_index, 2) << "NV12 readback requests at most 2 planes!";

	if (!impl_on_gpu_) {
	// We could not identify the impl_on_gpu, which means there's nothing else
	// we can do here (everything should already be cleaned up).
	return;
	}

	impl_on_gpu_->ReadbackDone();

	// Mark plane readback as completed and store results in the readback context:
	outstanding_reads_--;
	plane_results_[plane_index] = std::move(async_result);

	// Check if all planes have finished readback, send the result and clean up
	// the readback context if so:
	if (outstanding_reads_ == 0) {
	auto result = std::make_unique<CopyOutputResultSkiaNV12>(
	impl_on_gpu_.get(), result_rect_, std::move(plane_results_));

	request_->SendResult(std::move(result));
	}
	}

	NV12PlanePixelReadContext::NV12PlanePixelReadContext(
	scoped_refptr<NV12PlanesReadbackContext> nv12_planes_readback,
	int plane_index)
	: nv12_planes_readback(std::move(nv12_planes_readback)),
	plane_index(plane_index) {}
	NV12PlanePixelReadContext::~NV12PlanePixelReadContext() = default;

	CopyOutputResultSkiaNV12::CopyOutputResultSkiaNV12(
	SkiaOutputSurfaceImplOnGpu* impl,
	const gfx::Rect& rect,
	std::array<std::unique_ptr<const SkImage::AsyncReadResult>, 2>
	async_read_results)
	: CopyOutputResult(Format::I420_PLANES,
	Destination::kSystemMemory,
	rect,
	/needs_lock_for_bitmap=/false) {
	DCHECK_EQ(0, size().width() % 2);
	DCHECK_EQ(0, size().height() % 2);

	for (auto& async_read_result : async_read_results) {
	plane_readback_results_.push_back(std::make_unique<AsyncReadResultHelper>(
	impl, std::move(async_read_result)));
	}
	}

	CopyOutputResultSkiaNV12::~CopyOutputResultSkiaNV12() = default;

	bool CopyOutputResultSkiaNV12::ReadNV12Planes(base::span<uint8_t> y_out,
	int y_out_stride,
	base::span<uint8_t> uv_out,
	int uv_out_stride) const {
	const auto plane_pointer = [y_out, uv_out](int plane_number) {
	return plane_number == 0 ? y_out.data() : uv_out.data();
	};

	const auto plane_stride = [y_out_stride, uv_out_stride](int plane_number) {
	return plane_number == 0 ? y_out_stride : uv_out_stride;
	};

	for (size_t i = 0; i < kNV12MaxPlanes; ++i) {
	// The ptr to the helper is not set, which means that readback for this
	// plane has failed. Return failure, partial results are not useful.
	if (!plane_readback_results_[i]) {
	return false;
	}

	const AsyncReadResultHelper& result = *plane_readback_results_[i].get();

	// Hold the lock so the AsyncReadResultHelper will not be reset during
	// pixel data reading.
	base::AutoLock auto_lock(result.lock());
	DCHECK_EQ(1, result->count());

	// The \|result\| has been reset.
	if (!result) {
	return false;
	}

	// TODO(crbug.com/384959115): Verify span size before calling into libyuv.
	auto* data = static_cast<const uint8_t*>(result->data(0));
	libyuv::CopyPlane(data, result->rowBytes(0), plane_pointer(i),
	plane_stride(i), width(i), height(i));
	}

	return true;
	}

	// static
	void CopyOutputResultSkiaNV12::OnNV12PlaneReadbackDone(
	void* c,
	std::unique_ptr<const SkSurface::AsyncReadResult> async_result) {
	auto context = base::WrapUnique(static_cast<NV12PlanePixelReadContext*>(c));

	context->nv12_planes_readback->PlaneReadbackDone(context->plane_index,
	std::move(async_result));
	}

	} // namespace viz