src/dawn/native/null/DeviceNull.cpp - dawn - Git at Google

 // Copyright 2017 The Dawn & Tint Authors
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are met:
 //
 // 1. Redistributions of source code must retain the above copyright notice, this
 //    list of conditions and the following disclaimer.
 //
 // 2. Redistributions in binary form must reproduce the above copyright notice,
 //    this list of conditions and the following disclaimer in the documentation
 //    and/or other materials provided with the distribution.
 //
 // 3. Neither the name of the copyright holder nor the names of its
 //    contributors may be used to endorse or promote products derived from
 //    this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 #include "dawn/native/null/DeviceNull.h"

 #include <limits>
 #include <utility>

 #include "dawn/native/BackendConnection.h"
 #include "dawn/native/ChainUtils.h"
 #include "dawn/native/Commands.h"
 #include "dawn/native/ErrorData.h"
 #include "dawn/native/Instance.h"
 #include "dawn/native/Surface.h"
 #include "dawn/native/TintUtils.h"
 #include "partition_alloc/pointers/raw_ptr.h"

 #include "tint/tint.h"

 namespace dawn::native::null {

 // Implementation of pre-Device objects: the null physical device, null backend connection and
 // Connect()

 PhysicalDevice::PhysicalDevice(InstanceBase* instance)
     : PhysicalDeviceBase(instance, wgpu::BackendType::Null) {
     mVendorId = 0;
     mDeviceId = 0;
     mName = "Null backend";
     mAdapterType = wgpu::AdapterType::CPU;
     MaybeError err = Initialize();
     DAWN_ASSERT(err.IsSuccess());
 }

 PhysicalDevice::~PhysicalDevice() = default;

 bool PhysicalDevice::SupportsExternalImages() const {
     return false;
 }

 bool PhysicalDevice::SupportsFeatureLevel(FeatureLevel) const {
     return true;
 }

 ResultOrError<PhysicalDeviceSurfaceCapabilities> PhysicalDevice::GetSurfaceCapabilities(
     const Surface* surface) const {
     PhysicalDeviceSurfaceCapabilities capabilities;
     capabilities.formats = {wgpu::TextureFormat::BGRA8Unorm};
     capabilities.presentModes = {wgpu::PresentMode::Fifo};
     capabilities.alphaModes = {wgpu::CompositeAlphaMode::Auto};
     return capabilities;
 }

 MaybeError PhysicalDevice::InitializeImpl() {
     return {};
 }

 void PhysicalDevice::InitializeSupportedFeaturesImpl() {
     // Enable all features by default for the convenience of tests.
     for (uint32_t i = 0; i < kEnumCount<Feature>; i++) {
         EnableFeature(static_cast<Feature>(i));
     }
 }

 MaybeError PhysicalDevice::InitializeSupportedLimitsImpl(CombinedLimits* limits) {
     GetDefaultLimitsForSupportedFeatureLevel(&limits->v1);
     // Set the subgroups limit, as DeviceNull should support subgroups feature.
     limits->experimentalSubgroupLimits.minSubgroupSize = 4;
     limits->experimentalSubgroupLimits.maxSubgroupSize = 128;
     return {};
 }

 void PhysicalDevice::SetupBackendAdapterToggles(TogglesState* adpterToggles) const {}

 void PhysicalDevice::SetupBackendDeviceToggles(TogglesState* deviceToggles) const {}

 ResultOrError<Ref<DeviceBase>> PhysicalDevice::CreateDeviceImpl(
     AdapterBase* adapter,
     const UnpackedPtr<DeviceDescriptor>& descriptor,
     const TogglesState& deviceToggles,
     Ref<DeviceBase::DeviceLostEvent>&& lostEvent) {
     return Device::Create(adapter, descriptor, deviceToggles, std::move(lostEvent));
 }

 void PhysicalDevice::PopulateBackendProperties(UnpackedPtr<AdapterProperties>& properties) const {
     if (auto* memoryHeapProperties = properties.Get<AdapterPropertiesMemoryHeaps>()) {
         auto* heapInfo = new MemoryHeapInfo[1];
         memoryHeapProperties->heapCount = 1;
         memoryHeapProperties->heapInfo = heapInfo;

         heapInfo[0].size = 1024 * 1024 * 1024;
         heapInfo[0].properties = wgpu::HeapProperty::DeviceLocal | wgpu::HeapProperty::HostVisible |
                                  wgpu::HeapProperty::HostCached;
     }
     if (auto* d3dProperties = properties.Get<AdapterPropertiesD3D>()) {
         d3dProperties->shaderModel = 0;
     }
 }

 FeatureValidationResult PhysicalDevice::ValidateFeatureSupportedWithTogglesImpl(
     wgpu::FeatureName feature,
     const TogglesState& toggles) const {
     return {};
 }

 class Backend : public BackendConnection {
   public:
     explicit Backend(InstanceBase* instance)
         : BackendConnection(instance, wgpu::BackendType::Null) {}

     std::vector<Ref<PhysicalDeviceBase>> DiscoverPhysicalDevices(
         const UnpackedPtr<RequestAdapterOptions>& options) override {
         if (options->forceFallbackAdapter) {
             return {};
         }
         // There is always a single Null physical device because it is purely CPU based
         // and doesn't depend on the system.
         if (mPhysicalDevice == nullptr) {
             mPhysicalDevice = AcquireRef(new PhysicalDevice(GetInstance()));
         }
         return {mPhysicalDevice};
     }

     void ClearPhysicalDevices() override { mPhysicalDevice = nullptr; }
     size_t GetPhysicalDeviceCountForTesting() const override {
         return mPhysicalDevice != nullptr ? 1 : 0;
     }

   private:
     Ref<PhysicalDevice> mPhysicalDevice;
 };

 BackendConnection* Connect(InstanceBase* instance) {
     return new Backend(instance);
 }

 struct CopyFromStagingToBufferOperation : PendingOperation {
     void Execute() override {
         destination->CopyFromStaging(staging, sourceOffset, destinationOffset, size);
     }

     raw_ptr<BufferBase> staging;
     Ref<Buffer> destination;
     uint64_t sourceOffset;
     uint64_t destinationOffset;
     uint64_t size;
 };

 // Device

 // static
 ResultOrError<Ref<Device>> Device::Create(AdapterBase* adapter,
                                           const UnpackedPtr<DeviceDescriptor>& descriptor,
                                           const TogglesState& deviceToggles,
                                           Ref<DeviceBase::DeviceLostEvent>&& lostEvent) {
     Ref<Device> device =
         AcquireRef(new Device(adapter, descriptor, deviceToggles, std::move(lostEvent)));
     DAWN_TRY(device->Initialize(descriptor));
     return device;
 }

 Device::~Device() {
     Destroy();
 }

 MaybeError Device::Initialize(const UnpackedPtr<DeviceDescriptor>& descriptor) {
     return DeviceBase::Initialize(AcquireRef(new Queue(this, &descriptor->defaultQueue)));
 }

 ResultOrError<Ref<BindGroupBase>> Device::CreateBindGroupImpl(
     const BindGroupDescriptor* descriptor) {
     return AcquireRef(new BindGroup(this, descriptor));
 }
 ResultOrError<Ref<BindGroupLayoutInternalBase>> Device::CreateBindGroupLayoutImpl(
     const BindGroupLayoutDescriptor* descriptor) {
     return AcquireRef(new BindGroupLayout(this, descriptor));
 }
 ResultOrError<Ref<BufferBase>> Device::CreateBufferImpl(
     const UnpackedPtr<BufferDescriptor>& descriptor) {
     DAWN_TRY(IncrementMemoryUsage(descriptor->size));
     return AcquireRef(new Buffer(this, descriptor));
 }
 ResultOrError<Ref<CommandBufferBase>> Device::CreateCommandBuffer(
     CommandEncoder* encoder,
     const CommandBufferDescriptor* descriptor) {
     return AcquireRef(new CommandBuffer(encoder, descriptor));
 }
 Ref<ComputePipelineBase> Device::CreateUninitializedComputePipelineImpl(
     const UnpackedPtr<ComputePipelineDescriptor>& descriptor) {
     return AcquireRef(new ComputePipeline(this, descriptor));
 }
 ResultOrError<Ref<PipelineLayoutBase>> Device::CreatePipelineLayoutImpl(
     const UnpackedPtr<PipelineLayoutDescriptor>& descriptor) {
     return AcquireRef(new PipelineLayout(this, descriptor));
 }
 ResultOrError<Ref<QuerySetBase>> Device::CreateQuerySetImpl(const QuerySetDescriptor* descriptor) {
     return AcquireRef(new QuerySet(this, descriptor));
 }
 Ref<RenderPipelineBase> Device::CreateUninitializedRenderPipelineImpl(
     const UnpackedPtr<RenderPipelineDescriptor>& descriptor) {
     return AcquireRef(new RenderPipeline(this, descriptor));
 }
 ResultOrError<Ref<SamplerBase>> Device::CreateSamplerImpl(const SamplerDescriptor* descriptor) {
     return AcquireRef(new Sampler(this, descriptor));
 }
 ResultOrError<Ref<ShaderModuleBase>> Device::CreateShaderModuleImpl(
     const UnpackedPtr<ShaderModuleDescriptor>& descriptor,
     ShaderModuleParseResult* parseResult,
     OwnedCompilationMessages* compilationMessages) {
     Ref<ShaderModule> module = AcquireRef(new ShaderModule(this, descriptor));
     DAWN_TRY(module->Initialize(parseResult, compilationMessages));
     return module;
 }
 ResultOrError<Ref<SwapChainBase>> Device::CreateSwapChainImpl(Surface* surface,
                                                               SwapChainBase* previousSwapChain,
                                                               const SurfaceConfiguration* config) {
     return SwapChain::Create(this, surface, previousSwapChain, config);
 }
 ResultOrError<Ref<TextureBase>> Device::CreateTextureImpl(
     const UnpackedPtr<TextureDescriptor>& descriptor) {
     return AcquireRef(new Texture(this, descriptor));
 }
 ResultOrError<Ref<TextureViewBase>> Device::CreateTextureViewImpl(
     TextureBase* texture,
     const TextureViewDescriptor* descriptor) {
     return AcquireRef(new TextureView(texture, descriptor));
 }

 ResultOrError<wgpu::TextureUsage> Device::GetSupportedSurfaceUsageImpl(
     const Surface* surface) const {
     return wgpu::TextureUsage::RenderAttachment;
 }

 void Device::DestroyImpl() {
     DAWN_ASSERT(GetState() == State::Disconnected);
     // TODO(crbug.com/dawn/831): DestroyImpl is called from two places.
     // - It may be called if the device is explicitly destroyed with APIDestroy.
     //   This case is NOT thread-safe and needs proper synchronization with other
     //   simultaneous uses of the device.
     // - It may be called when the last ref to the device is dropped and the device
     //   is implicitly destroyed. This case is thread-safe because there are no
     //   other threads using the device since there are no other live refs.

     // Clear pending operations before checking mMemoryUsage because some operations keep a
     // reference to Buffers.
     mPendingOperations.clear();
     DAWN_ASSERT(mMemoryUsage == 0);
 }

 void Device::ForgetPendingOperations() {
     mPendingOperations.clear();
 }

 MaybeError Device::CopyFromStagingToBufferImpl(BufferBase* source,
                                                uint64_t sourceOffset,
                                                BufferBase* destination,
                                                uint64_t destinationOffset,
                                                uint64_t size) {
     if (IsToggleEnabled(Toggle::LazyClearResourceOnFirstUse)) {
         destination->SetInitialized(true);
     }

     auto operation = std::make_unique<CopyFromStagingToBufferOperation>();
     operation->staging = source;
     operation->destination = ToBackend(destination);
     operation->sourceOffset = sourceOffset;
     operation->destinationOffset = destinationOffset;
     operation->size = size;

     AddPendingOperation(std::move(operation));

     return {};
 }

 MaybeError Device::CopyFromStagingToTextureImpl(const BufferBase* source,
                                                 const TextureDataLayout& src,
                                                 const TextureCopy& dst,
                                                 const Extent3D& copySizePixels) {
     return {};
 }

 MaybeError Device::IncrementMemoryUsage(uint64_t bytes) {
     static_assert(kMaxMemoryUsage <= std::numeric_limits<size_t>::max());
     if (bytes > kMaxMemoryUsage || mMemoryUsage > kMaxMemoryUsage - bytes) {
         return DAWN_OUT_OF_MEMORY_ERROR("Out of memory.");
     }
     mMemoryUsage += bytes;
     return {};
 }

 void Device::DecrementMemoryUsage(uint64_t bytes) {
     DAWN_ASSERT(mMemoryUsage >= bytes);
     mMemoryUsage -= bytes;
 }

 MaybeError Device::TickImpl() {
     return SubmitPendingOperations();
 }

 void Device::AddPendingOperation(std::unique_ptr<PendingOperation> operation) {
     mPendingOperations.emplace_back(std::move(operation));
 }

 MaybeError Device::SubmitPendingOperations() {
     for (auto& operation : mPendingOperations) {
         operation->Execute();
     }
     mPendingOperations.clear();

     DAWN_TRY(GetQueue()->CheckPassedSerials());
     GetQueue()->IncrementLastSubmittedCommandSerial();

     return {};
 }

 // BindGroupDataHolder

 BindGroupDataHolder::BindGroupDataHolder(size_t size)
     : mBindingDataAllocation(malloc(size))  // malloc is guaranteed to return a
                                             // pointer aligned enough for the allocation
 {}

 BindGroupDataHolder::~BindGroupDataHolder() {
     free(mBindingDataAllocation.ExtractAsDangling());
 }

 // BindGroup

 BindGroup::BindGroup(DeviceBase* device, const BindGroupDescriptor* descriptor)
     : BindGroupDataHolder(descriptor->layout->GetInternalBindGroupLayout()->GetBindingDataSize()),
       BindGroupBase(device, descriptor, mBindingDataAllocation) {}

 // BindGroupLayout

 BindGroupLayout::BindGroupLayout(DeviceBase* device, const BindGroupLayoutDescriptor* descriptor)
     : BindGroupLayoutInternalBase(device, descriptor) {}

 // Buffer

 Buffer::Buffer(Device* device, const UnpackedPtr<BufferDescriptor>& descriptor)
     : BufferBase(device, descriptor) {
     mBackingData = std::unique_ptr<uint8_t[]>(new uint8_t[GetSize()]);
     mAllocatedSize = GetSize();
 }

 bool Buffer::IsCPUWritableAtCreation() const {
     // Only return true for mappable buffers so we can test cases that need / don't need a
     // staging buffer.
     return (GetUsage() & (wgpu::BufferUsage::MapRead | wgpu::BufferUsage::MapWrite)) != 0;
 }

 MaybeError Buffer::MapAtCreationImpl() {
     return {};
 }

 void Buffer::CopyFromStaging(BufferBase* staging,
                              uint64_t sourceOffset,
                              uint64_t destinationOffset,
                              uint64_t size) {
     uint8_t* ptr = reinterpret_cast<uint8_t*>(staging->GetMappedPointer());
     memcpy(mBackingData.get() + destinationOffset, ptr + sourceOffset, size);
 }

 void Buffer::DoWriteBuffer(uint64_t bufferOffset, const void* data, size_t size) {
     DAWN_ASSERT(bufferOffset + size <= GetSize());
     DAWN_ASSERT(mBackingData);
     memcpy(mBackingData.get() + bufferOffset, data, size);
 }

 MaybeError Buffer::MapAsyncImpl(wgpu::MapMode mode, size_t offset, size_t size) {
     return {};
 }

 void* Buffer::GetMappedPointer() {
     return mBackingData.get();
 }

 void Buffer::UnmapImpl() {}

 void Buffer::DestroyImpl() {
     // TODO(crbug.com/dawn/831): DestroyImpl is called from two places.
     // - It may be called if the buffer is explicitly destroyed with APIDestroy.
     //   This case is NOT thread-safe and needs proper synchronization with other
     //   simultaneous uses of the buffer.
     // - It may be called when the last ref to the buffer is dropped and the buffer
     //   is implicitly destroyed. This case is thread-safe because there are no
     //   other threads using the buffer since there are no other live refs.
     BufferBase::DestroyImpl();
     ToBackend(GetDevice())->DecrementMemoryUsage(GetSize());
 }

 // CommandBuffer

 CommandBuffer::CommandBuffer(CommandEncoder* encoder, const CommandBufferDescriptor* descriptor)
     : CommandBufferBase(encoder, descriptor) {}

 // QuerySet

 QuerySet::QuerySet(Device* device, const QuerySetDescriptor* descriptor)
     : QuerySetBase(device, descriptor) {}

 // Queue

 Queue::Queue(Device* device, const QueueDescriptor* descriptor) : QueueBase(device, descriptor) {}

 Queue::~Queue() {}

 MaybeError Queue::SubmitImpl(uint32_t, CommandBufferBase* const*) {
     Device* device = ToBackend(GetDevice());

     DAWN_TRY(device->SubmitPendingOperations());

     return {};
 }

 MaybeError Queue::WriteBufferImpl(BufferBase* buffer,
                                   uint64_t bufferOffset,
                                   const void* data,
                                   size_t size) {
     ToBackend(buffer)->DoWriteBuffer(bufferOffset, data, size);
     return {};
 }

 ResultOrError<ExecutionSerial> Queue::CheckAndUpdateCompletedSerials() {
     return GetLastSubmittedCommandSerial();
 }

 void Queue::ForceEventualFlushOfCommands() {}

 bool Queue::HasPendingCommands() const {
     return false;
 }

 MaybeError Queue::SubmitPendingCommands() {
     return {};
 }

 ResultOrError<bool> Queue::WaitForQueueSerial(ExecutionSerial serial, Nanoseconds timeout) {
     return true;
 }

 MaybeError Queue::WaitForIdleForDestruction() {
     ToBackend(GetDevice())->ForgetPendingOperations();
     return {};
 }

 // ComputePipeline
 MaybeError ComputePipeline::InitializeImpl() {
     const ProgrammableStage& computeStage = GetStage(SingleShaderStage::Compute);

     tint::Program transformedProgram;
     tint::ast::transform::Manager transformManager;
     tint::ast::transform::DataMap transformInputs;

     if (!computeStage.metadata->overrides.empty()) {
         transformManager.Add<tint::ast::transform::SingleEntryPoint>();
         transformInputs.Add<tint::ast::transform::SingleEntryPoint::Config>(
             computeStage.entryPoint.c_str());

         // This needs to run after SingleEntryPoint transform which removes unused overrides for
         // current entry point.
         transformManager.Add<tint::ast::transform::SubstituteOverride>();
         transformInputs.Add<tint::ast::transform::SubstituteOverride::Config>(
             BuildSubstituteOverridesTransformConfig(computeStage));
     }

     auto tintProgram = computeStage.module->GetTintProgram();
     DAWN_TRY_ASSIGN(transformedProgram, RunTransforms(&transformManager, &(tintProgram->program),
                                                       transformInputs, nullptr, nullptr));

     // Do the workgroup size validation, although different backend will have different
     // fullSubgroups parameter.
     const CombinedLimits& limits = GetDevice()->GetLimits();
     Extent3D _;
     DAWN_TRY_ASSIGN(
         _, ValidateComputeStageWorkgroupSize(
                transformedProgram, computeStage.entryPoint.c_str(),
                LimitsForCompilationRequest::Create(limits.v1), /* maxSubgroupSizeForFullSubgroups */
                IsFullSubgroupsRequired()
                    ? std::make_optional(limits.experimentalSubgroupLimits.maxSubgroupSize)
                    : std::nullopt));

     return {};
 }

 // RenderPipeline
 MaybeError RenderPipeline::InitializeImpl() {
     return {};
 }

 // SwapChain

 // static
 ResultOrError<Ref<SwapChain>> SwapChain::Create(Device* device,
                                                 Surface* surface,
                                                 SwapChainBase* previousSwapChain,
                                                 const SurfaceConfiguration* config) {
     Ref<SwapChain> swapchain = AcquireRef(new SwapChain(device, surface, config));
     DAWN_TRY(swapchain->Initialize(previousSwapChain));
     return swapchain;
 }

 MaybeError SwapChain::Initialize(SwapChainBase* previousSwapChain) {
     if (previousSwapChain != nullptr) {
         // TODO(crbug.com/dawn/269): figure out what should happen when surfaces are used by
         // multiple backends one after the other. It probably needs to block until the backend
         // and GPU are completely finished with the previous swapchain.
         DAWN_INVALID_IF(previousSwapChain->GetBackendType() != wgpu::BackendType::Null,
                         "null::SwapChain cannot switch between APIs");
     }

     return {};
 }

 SwapChain::~SwapChain() = default;

 MaybeError SwapChain::PresentImpl() {
     mTexture->APIDestroy();
     mTexture = nullptr;
     return {};
 }

 ResultOrError<SwapChainTextureInfo> SwapChain::GetCurrentTextureImpl() {
     TextureDescriptor textureDesc = GetSwapChainBaseTextureDescriptor(this);
     mTexture = AcquireRef(new Texture(GetDevice(), Unpack(&textureDesc)));
     SwapChainTextureInfo info;
     info.texture = mTexture;
     info.status = wgpu::SurfaceGetCurrentTextureStatus::Success;
     info.suboptimal = false;
     return info;
 }

 void SwapChain::DetachFromSurfaceImpl() {
     if (mTexture != nullptr) {
         mTexture->APIDestroy();
         mTexture = nullptr;
     }
 }

 // ShaderModule

 MaybeError ShaderModule::Initialize(ShaderModuleParseResult* parseResult,
                                     OwnedCompilationMessages* compilationMessages) {
     return InitializeBase(parseResult, compilationMessages);
 }

 uint32_t Device::GetOptimalBytesPerRowAlignment() const {
     return 1;
 }

 uint64_t Device::GetOptimalBufferToTextureCopyOffsetAlignment() const {
     return 1;
 }

 float Device::GetTimestampPeriodInNS() const {
     return 1.0f;
 }

 bool Device::IsResolveTextureBlitWithDrawSupported() const {
     return true;
 }

 Texture::Texture(DeviceBase* device, const UnpackedPtr<TextureDescriptor>& descriptor)
     : TextureBase(device, descriptor) {}

 }  // namespace dawn::native::null
	// Copyright 2017 The Dawn & Tint Authors
	//
	// Redistribution and use in source and binary forms, with or without
	// modification, are permitted provided that the following conditions are met:
	//
	// 1. Redistributions of source code must retain the above copyright notice, this
	// list of conditions and the following disclaimer.
	//
	// 2. Redistributions in binary form must reproduce the above copyright notice,
	// this list of conditions and the following disclaimer in the documentation
	// and/or other materials provided with the distribution.
	//
	// 3. Neither the name of the copyright holder nor the names of its
	// contributors may be used to endorse or promote products derived from
	// this software without specific prior written permission.
	//
	// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
	// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
	// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
	// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
	// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
	// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
	// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

	#include "dawn/native/null/DeviceNull.h"

	#include <limits>
	#include <utility>

	#include "dawn/native/BackendConnection.h"
	#include "dawn/native/ChainUtils.h"
	#include "dawn/native/Commands.h"
	#include "dawn/native/ErrorData.h"
	#include "dawn/native/Instance.h"
	#include "dawn/native/Surface.h"
	#include "dawn/native/TintUtils.h"
	#include "partition_alloc/pointers/raw_ptr.h"

	#include "tint/tint.h"

	namespace dawn::native::null {

	// Implementation of pre-Device objects: the null physical device, null backend connection and
	// Connect()

	PhysicalDevice::PhysicalDevice(InstanceBase* instance)
	: PhysicalDeviceBase(instance, wgpu::BackendType::Null) {
	mVendorId = 0;
	mDeviceId = 0;
	mName = "Null backend";
	mAdapterType = wgpu::AdapterType::CPU;
	MaybeError err = Initialize();
	DAWN_ASSERT(err.IsSuccess());
	}

	PhysicalDevice::~PhysicalDevice() = default;

	bool PhysicalDevice::SupportsExternalImages() const {
	return false;
	}

	bool PhysicalDevice::SupportsFeatureLevel(FeatureLevel) const {
	return true;
	}

	ResultOrError<PhysicalDeviceSurfaceCapabilities> PhysicalDevice::GetSurfaceCapabilities(
	const Surface* surface) const {
	PhysicalDeviceSurfaceCapabilities capabilities;
	capabilities.formats = {wgpu::TextureFormat::BGRA8Unorm};
	capabilities.presentModes = {wgpu::PresentMode::Fifo};
	capabilities.alphaModes = {wgpu::CompositeAlphaMode::Auto};
	return capabilities;
	}

	MaybeError PhysicalDevice::InitializeImpl() {
	return {};
	}

	void PhysicalDevice::InitializeSupportedFeaturesImpl() {
	// Enable all features by default for the convenience of tests.
	for (uint32_t i = 0; i < kEnumCount<Feature>; i++) {
	EnableFeature(static_cast<Feature>(i));
	}
	}

	MaybeError PhysicalDevice::InitializeSupportedLimitsImpl(CombinedLimits* limits) {
	GetDefaultLimitsForSupportedFeatureLevel(&limits->v1);
	// Set the subgroups limit, as DeviceNull should support subgroups feature.
	limits->experimentalSubgroupLimits.minSubgroupSize = 4;
	limits->experimentalSubgroupLimits.maxSubgroupSize = 128;
	return {};
	}

	void PhysicalDevice::SetupBackendAdapterToggles(TogglesState* adpterToggles) const {}

	void PhysicalDevice::SetupBackendDeviceToggles(TogglesState* deviceToggles) const {}

	ResultOrError<Ref<DeviceBase>> PhysicalDevice::CreateDeviceImpl(
	AdapterBase* adapter,
	const UnpackedPtr<DeviceDescriptor>& descriptor,
	const TogglesState& deviceToggles,
	Ref<DeviceBase::DeviceLostEvent>&& lostEvent) {
	return Device::Create(adapter, descriptor, deviceToggles, std::move(lostEvent));
	}

	void PhysicalDevice::PopulateBackendProperties(UnpackedPtr<AdapterProperties>& properties) const {
	if (auto* memoryHeapProperties = properties.Get<AdapterPropertiesMemoryHeaps>()) {
	auto* heapInfo = new MemoryHeapInfo[1];
	memoryHeapProperties->heapCount = 1;
	memoryHeapProperties->heapInfo = heapInfo;

	heapInfo[0].size = 1024 * 1024 * 1024;
	heapInfo[0].properties = wgpu::HeapProperty::DeviceLocal \| wgpu::HeapProperty::HostVisible \|
	wgpu::HeapProperty::HostCached;
	}
	if (auto* d3dProperties = properties.Get<AdapterPropertiesD3D>()) {
	d3dProperties->shaderModel = 0;
	}
	}

	FeatureValidationResult PhysicalDevice::ValidateFeatureSupportedWithTogglesImpl(
	wgpu::FeatureName feature,
	const TogglesState& toggles) const {
	return {};
	}

	class Backend : public BackendConnection {
	public:
	explicit Backend(InstanceBase* instance)
	: BackendConnection(instance, wgpu::BackendType::Null) {}

	std::vector<Ref<PhysicalDeviceBase>> DiscoverPhysicalDevices(
	const UnpackedPtr<RequestAdapterOptions>& options) override {
	if (options->forceFallbackAdapter) {
	return {};
	}
	// There is always a single Null physical device because it is purely CPU based
	// and doesn't depend on the system.
	if (mPhysicalDevice == nullptr) {
	mPhysicalDevice = AcquireRef(new PhysicalDevice(GetInstance()));
	}
	return {mPhysicalDevice};
	}

	void ClearPhysicalDevices() override { mPhysicalDevice = nullptr; }
	size_t GetPhysicalDeviceCountForTesting() const override {
	return mPhysicalDevice != nullptr ? 1 : 0;
	}

	private:
	Ref<PhysicalDevice> mPhysicalDevice;
	};

	BackendConnection* Connect(InstanceBase* instance) {
	return new Backend(instance);
	}

	struct CopyFromStagingToBufferOperation : PendingOperation {
	void Execute() override {
	destination->CopyFromStaging(staging, sourceOffset, destinationOffset, size);
	}

	raw_ptr<BufferBase> staging;
	Ref<Buffer> destination;
	uint64_t sourceOffset;
	uint64_t destinationOffset;
	uint64_t size;
	};

	// Device

	// static
	ResultOrError<Ref<Device>> Device::Create(AdapterBase* adapter,
	const UnpackedPtr<DeviceDescriptor>& descriptor,
	const TogglesState& deviceToggles,
	Ref<DeviceBase::DeviceLostEvent>&& lostEvent) {
	Ref<Device> device =
	AcquireRef(new Device(adapter, descriptor, deviceToggles, std::move(lostEvent)));
	DAWN_TRY(device->Initialize(descriptor));
	return device;
	}

	Device::~Device() {
	Destroy();
	}

	MaybeError Device::Initialize(const UnpackedPtr<DeviceDescriptor>& descriptor) {
	return DeviceBase::Initialize(AcquireRef(new Queue(this, &descriptor->defaultQueue)));
	}

	ResultOrError<Ref<BindGroupBase>> Device::CreateBindGroupImpl(
	const BindGroupDescriptor* descriptor) {
	return AcquireRef(new BindGroup(this, descriptor));
	}
	ResultOrError<Ref<BindGroupLayoutInternalBase>> Device::CreateBindGroupLayoutImpl(
	const BindGroupLayoutDescriptor* descriptor) {
	return AcquireRef(new BindGroupLayout(this, descriptor));
	}
	ResultOrError<Ref<BufferBase>> Device::CreateBufferImpl(
	const UnpackedPtr<BufferDescriptor>& descriptor) {
	DAWN_TRY(IncrementMemoryUsage(descriptor->size));
	return AcquireRef(new Buffer(this, descriptor));
	}
	ResultOrError<Ref<CommandBufferBase>> Device::CreateCommandBuffer(
	CommandEncoder* encoder,
	const CommandBufferDescriptor* descriptor) {
	return AcquireRef(new CommandBuffer(encoder, descriptor));
	}
	Ref<ComputePipelineBase> Device::CreateUninitializedComputePipelineImpl(
	const UnpackedPtr<ComputePipelineDescriptor>& descriptor) {
	return AcquireRef(new ComputePipeline(this, descriptor));
	}
	ResultOrError<Ref<PipelineLayoutBase>> Device::CreatePipelineLayoutImpl(
	const UnpackedPtr<PipelineLayoutDescriptor>& descriptor) {
	return AcquireRef(new PipelineLayout(this, descriptor));
	}
	ResultOrError<Ref<QuerySetBase>> Device::CreateQuerySetImpl(const QuerySetDescriptor* descriptor) {
	return AcquireRef(new QuerySet(this, descriptor));
	}
	Ref<RenderPipelineBase> Device::CreateUninitializedRenderPipelineImpl(
	const UnpackedPtr<RenderPipelineDescriptor>& descriptor) {
	return AcquireRef(new RenderPipeline(this, descriptor));
	}
	ResultOrError<Ref<SamplerBase>> Device::CreateSamplerImpl(const SamplerDescriptor* descriptor) {
	return AcquireRef(new Sampler(this, descriptor));
	}
	ResultOrError<Ref<ShaderModuleBase>> Device::CreateShaderModuleImpl(
	const UnpackedPtr<ShaderModuleDescriptor>& descriptor,
	ShaderModuleParseResult* parseResult,
	OwnedCompilationMessages* compilationMessages) {
	Ref<ShaderModule> module = AcquireRef(new ShaderModule(this, descriptor));
	DAWN_TRY(module->Initialize(parseResult, compilationMessages));
	return module;
	}
	ResultOrError<Ref<SwapChainBase>> Device::CreateSwapChainImpl(Surface* surface,
	SwapChainBase* previousSwapChain,
	const SurfaceConfiguration* config) {
	return SwapChain::Create(this, surface, previousSwapChain, config);
	}
	ResultOrError<Ref<TextureBase>> Device::CreateTextureImpl(
	const UnpackedPtr<TextureDescriptor>& descriptor) {
	return AcquireRef(new Texture(this, descriptor));
	}
	ResultOrError<Ref<TextureViewBase>> Device::CreateTextureViewImpl(
	TextureBase* texture,
	const TextureViewDescriptor* descriptor) {
	return AcquireRef(new TextureView(texture, descriptor));
	}

	ResultOrError<wgpu::TextureUsage> Device::GetSupportedSurfaceUsageImpl(
	const Surface* surface) const {
	return wgpu::TextureUsage::RenderAttachment;
	}

	void Device::DestroyImpl() {
	DAWN_ASSERT(GetState() == State::Disconnected);
	// TODO(crbug.com/dawn/831): DestroyImpl is called from two places.
	// - It may be called if the device is explicitly destroyed with APIDestroy.
	// This case is NOT thread-safe and needs proper synchronization with other
	// simultaneous uses of the device.
	// - It may be called when the last ref to the device is dropped and the device
	// is implicitly destroyed. This case is thread-safe because there are no
	// other threads using the device since there are no other live refs.

	// Clear pending operations before checking mMemoryUsage because some operations keep a
	// reference to Buffers.
	mPendingOperations.clear();
	DAWN_ASSERT(mMemoryUsage == 0);
	}

	void Device::ForgetPendingOperations() {
	mPendingOperations.clear();
	}

	MaybeError Device::CopyFromStagingToBufferImpl(BufferBase* source,
	uint64_t sourceOffset,
	BufferBase* destination,
	uint64_t destinationOffset,
	uint64_t size) {
	if (IsToggleEnabled(Toggle::LazyClearResourceOnFirstUse)) {
	destination->SetInitialized(true);
	}

	auto operation = std::make_unique<CopyFromStagingToBufferOperation>();
	operation->staging = source;
	operation->destination = ToBackend(destination);
	operation->sourceOffset = sourceOffset;
	operation->destinationOffset = destinationOffset;
	operation->size = size;

	AddPendingOperation(std::move(operation));

	return {};
	}

	MaybeError Device::CopyFromStagingToTextureImpl(const BufferBase* source,
	const TextureDataLayout& src,
	const TextureCopy& dst,
	const Extent3D& copySizePixels) {
	return {};
	}

	MaybeError Device::IncrementMemoryUsage(uint64_t bytes) {
	static_assert(kMaxMemoryUsage <= std::numeric_limits<size_t>::max());
	if (bytes > kMaxMemoryUsage \|\| mMemoryUsage > kMaxMemoryUsage - bytes) {
	return DAWN_OUT_OF_MEMORY_ERROR("Out of memory.");
	}
	mMemoryUsage += bytes;
	return {};
	}

	void Device::DecrementMemoryUsage(uint64_t bytes) {
	DAWN_ASSERT(mMemoryUsage >= bytes);
	mMemoryUsage -= bytes;
	}

	MaybeError Device::TickImpl() {
	return SubmitPendingOperations();
	}

	void Device::AddPendingOperation(std::unique_ptr<PendingOperation> operation) {
	mPendingOperations.emplace_back(std::move(operation));
	}

	MaybeError Device::SubmitPendingOperations() {
	for (auto& operation : mPendingOperations) {
	operation->Execute();
	}
	mPendingOperations.clear();

	DAWN_TRY(GetQueue()->CheckPassedSerials());
	GetQueue()->IncrementLastSubmittedCommandSerial();

	return {};
	}

	// BindGroupDataHolder

	BindGroupDataHolder::BindGroupDataHolder(size_t size)
	: mBindingDataAllocation(malloc(size)) // malloc is guaranteed to return a
	// pointer aligned enough for the allocation
	{}

	BindGroupDataHolder::~BindGroupDataHolder() {
	free(mBindingDataAllocation.ExtractAsDangling());
	}

	// BindGroup

	BindGroup::BindGroup(DeviceBase* device, const BindGroupDescriptor* descriptor)
	: BindGroupDataHolder(descriptor->layout->GetInternalBindGroupLayout()->GetBindingDataSize()),
	BindGroupBase(device, descriptor, mBindingDataAllocation) {}

	// BindGroupLayout

	BindGroupLayout::BindGroupLayout(DeviceBase* device, const BindGroupLayoutDescriptor* descriptor)
	: BindGroupLayoutInternalBase(device, descriptor) {}

	// Buffer

	Buffer::Buffer(Device* device, const UnpackedPtr<BufferDescriptor>& descriptor)
	: BufferBase(device, descriptor) {
	mBackingData = std::unique_ptr<uint8_t[]>(new uint8_t[GetSize()]);
	mAllocatedSize = GetSize();
	}

	bool Buffer::IsCPUWritableAtCreation() const {
	// Only return true for mappable buffers so we can test cases that need / don't need a
	// staging buffer.
	return (GetUsage() & (wgpu::BufferUsage::MapRead \| wgpu::BufferUsage::MapWrite)) != 0;
	}

	MaybeError Buffer::MapAtCreationImpl() {
	return {};
	}

	void Buffer::CopyFromStaging(BufferBase* staging,
	uint64_t sourceOffset,
	uint64_t destinationOffset,
	uint64_t size) {
	uint8_t* ptr = reinterpret_cast<uint8_t*>(staging->GetMappedPointer());
	memcpy(mBackingData.get() + destinationOffset, ptr + sourceOffset, size);
	}

	void Buffer::DoWriteBuffer(uint64_t bufferOffset, const void* data, size_t size) {
	DAWN_ASSERT(bufferOffset + size <= GetSize());
	DAWN_ASSERT(mBackingData);
	memcpy(mBackingData.get() + bufferOffset, data, size);
	}

	MaybeError Buffer::MapAsyncImpl(wgpu::MapMode mode, size_t offset, size_t size) {
	return {};
	}

	void* Buffer::GetMappedPointer() {
	return mBackingData.get();
	}

	void Buffer::UnmapImpl() {}

	void Buffer::DestroyImpl() {
	// TODO(crbug.com/dawn/831): DestroyImpl is called from two places.
	// - It may be called if the buffer is explicitly destroyed with APIDestroy.
	// This case is NOT thread-safe and needs proper synchronization with other
	// simultaneous uses of the buffer.
	// - It may be called when the last ref to the buffer is dropped and the buffer
	// is implicitly destroyed. This case is thread-safe because there are no
	// other threads using the buffer since there are no other live refs.
	BufferBase::DestroyImpl();
	ToBackend(GetDevice())->DecrementMemoryUsage(GetSize());
	}

	// CommandBuffer

	CommandBuffer::CommandBuffer(CommandEncoder* encoder, const CommandBufferDescriptor* descriptor)
	: CommandBufferBase(encoder, descriptor) {}

	// QuerySet

	QuerySet::QuerySet(Device* device, const QuerySetDescriptor* descriptor)
	: QuerySetBase(device, descriptor) {}

	// Queue

	Queue::Queue(Device* device, const QueueDescriptor* descriptor) : QueueBase(device, descriptor) {}

	Queue::~Queue() {}

	MaybeError Queue::SubmitImpl(uint32_t, CommandBufferBase* const*) {
	Device* device = ToBackend(GetDevice());

	DAWN_TRY(device->SubmitPendingOperations());

	return {};
	}

	MaybeError Queue::WriteBufferImpl(BufferBase* buffer,
	uint64_t bufferOffset,
	const void* data,
	size_t size) {
	ToBackend(buffer)->DoWriteBuffer(bufferOffset, data, size);
	return {};
	}

	ResultOrError<ExecutionSerial> Queue::CheckAndUpdateCompletedSerials() {
	return GetLastSubmittedCommandSerial();
	}

	void Queue::ForceEventualFlushOfCommands() {}

	bool Queue::HasPendingCommands() const {
	return false;
	}

	MaybeError Queue::SubmitPendingCommands() {
	return {};
	}

	ResultOrError<bool> Queue::WaitForQueueSerial(ExecutionSerial serial, Nanoseconds timeout) {
	return true;
	}

	MaybeError Queue::WaitForIdleForDestruction() {
	ToBackend(GetDevice())->ForgetPendingOperations();
	return {};
	}

	// ComputePipeline
	MaybeError ComputePipeline::InitializeImpl() {
	const ProgrammableStage& computeStage = GetStage(SingleShaderStage::Compute);

	tint::Program transformedProgram;
	tint::ast::transform::Manager transformManager;
	tint::ast::transform::DataMap transformInputs;

	if (!computeStage.metadata->overrides.empty()) {
	transformManager.Add<tint::ast::transform::SingleEntryPoint>();
	transformInputs.Add<tint::ast::transform::SingleEntryPoint::Config>(
	computeStage.entryPoint.c_str());

	// This needs to run after SingleEntryPoint transform which removes unused overrides for
	// current entry point.
	transformManager.Add<tint::ast::transform::SubstituteOverride>();
	transformInputs.Add<tint::ast::transform::SubstituteOverride::Config>(
	BuildSubstituteOverridesTransformConfig(computeStage));
	}

	auto tintProgram = computeStage.module->GetTintProgram();
	DAWN_TRY_ASSIGN(transformedProgram, RunTransforms(&transformManager, &(tintProgram->program),
	transformInputs, nullptr, nullptr));

	// Do the workgroup size validation, although different backend will have different
	// fullSubgroups parameter.
	const CombinedLimits& limits = GetDevice()->GetLimits();
	Extent3D _;
	DAWN_TRY_ASSIGN(
	_, ValidateComputeStageWorkgroupSize(
	transformedProgram, computeStage.entryPoint.c_str(),
	LimitsForCompilationRequest::Create(limits.v1), /* maxSubgroupSizeForFullSubgroups */
	IsFullSubgroupsRequired()
	? std::make_optional(limits.experimentalSubgroupLimits.maxSubgroupSize)
	: std::nullopt));

	return {};
	}

	// RenderPipeline
	MaybeError RenderPipeline::InitializeImpl() {
	return {};
	}

	// SwapChain

	// static
	ResultOrError<Ref<SwapChain>> SwapChain::Create(Device* device,
	Surface* surface,
	SwapChainBase* previousSwapChain,
	const SurfaceConfiguration* config) {
	Ref<SwapChain> swapchain = AcquireRef(new SwapChain(device, surface, config));
	DAWN_TRY(swapchain->Initialize(previousSwapChain));
	return swapchain;
	}

	MaybeError SwapChain::Initialize(SwapChainBase* previousSwapChain) {
	if (previousSwapChain != nullptr) {
	// TODO(crbug.com/dawn/269): figure out what should happen when surfaces are used by
	// multiple backends one after the other. It probably needs to block until the backend
	// and GPU are completely finished with the previous swapchain.
	DAWN_INVALID_IF(previousSwapChain->GetBackendType() != wgpu::BackendType::Null,
	"null::SwapChain cannot switch between APIs");
	}

	return {};
	}

	SwapChain::~SwapChain() = default;

	MaybeError SwapChain::PresentImpl() {
	mTexture->APIDestroy();
	mTexture = nullptr;
	return {};
	}

	ResultOrError<SwapChainTextureInfo> SwapChain::GetCurrentTextureImpl() {
	TextureDescriptor textureDesc = GetSwapChainBaseTextureDescriptor(this);
	mTexture = AcquireRef(new Texture(GetDevice(), Unpack(&textureDesc)));
	SwapChainTextureInfo info;
	info.texture = mTexture;
	info.status = wgpu::SurfaceGetCurrentTextureStatus::Success;
	info.suboptimal = false;
	return info;
	}

	void SwapChain::DetachFromSurfaceImpl() {
	if (mTexture != nullptr) {
	mTexture->APIDestroy();
	mTexture = nullptr;
	}
	}

	// ShaderModule

	MaybeError ShaderModule::Initialize(ShaderModuleParseResult* parseResult,
	OwnedCompilationMessages* compilationMessages) {
	return InitializeBase(parseResult, compilationMessages);
	}

	uint32_t Device::GetOptimalBytesPerRowAlignment() const {
	return 1;
	}

	uint64_t Device::GetOptimalBufferToTextureCopyOffsetAlignment() const {
	return 1;
	}

	float Device::GetTimestampPeriodInNS() const {
	return 1.0f;
	}

	bool Device::IsResolveTextureBlitWithDrawSupported() const {
	return true;
	}

	Texture::Texture(DeviceBase* device, const UnpackedPtr<TextureDescriptor>& descriptor)
	: TextureBase(device, descriptor) {}

	} // namespace dawn::native::null