// Copyright 2017 The Dawn Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "tests/DawnTest.h"

#include "common/Assert.h"
#include "common/GPUInfo.h"
#include "common/Log.h"
#include "common/Math.h"
#include "common/Platform.h"
#include "common/SystemUtils.h"
#include "dawn/dawn_proc.h"
#include "dawn_native/DawnNative.h"
#include "dawn_wire/WireClient.h"
#include "dawn_wire/WireServer.h"
#include "utils/SystemUtils.h"
#include "utils/TerribleCommandBuffer.h"
#include "utils/WGPUHelpers.h"

#include <algorithm>
#include <fstream>
#include <iomanip>
#include <sstream>
#include <unordered_map>

#ifdef DAWN_ENABLE_BACKEND_OPENGL
#    include "GLFW/glfw3.h"
#    include "dawn_native/OpenGLBackend.h"
#endif  // DAWN_ENABLE_BACKEND_OPENGL

namespace {

    std::string ParamName(wgpu::BackendType type) {
        switch (type) {
            case wgpu::BackendType::D3D12:
                return "D3D12";
            case wgpu::BackendType::Metal:
                return "Metal";
            case wgpu::BackendType::Null:
                return "Null";
            case wgpu::BackendType::OpenGL:
                return "OpenGL";
            case wgpu::BackendType::Vulkan:
                return "Vulkan";
            default:
                UNREACHABLE();
        }
    }

    const char* AdapterTypeName(wgpu::AdapterType type) {
        switch (type) {
            case wgpu::AdapterType::DiscreteGPU:
                return "Discrete GPU";
            case wgpu::AdapterType::IntegratedGPU:
                return "Integrated GPU";
            case wgpu::AdapterType::CPU:
                return "CPU";
            case wgpu::AdapterType::Unknown:
                return "Unknown";
            default:
                UNREACHABLE();
        }
    }

    struct MapReadUserdata {
        DawnTestBase* test;
        size_t slot;
    };

    DawnTestEnvironment* gTestEnv = nullptr;

}  // namespace

const RGBA8 RGBA8::kZero = RGBA8(0, 0, 0, 0);
const RGBA8 RGBA8::kBlack = RGBA8(0, 0, 0, 255);
const RGBA8 RGBA8::kRed = RGBA8(255, 0, 0, 255);
const RGBA8 RGBA8::kGreen = RGBA8(0, 255, 0, 255);
const RGBA8 RGBA8::kBlue = RGBA8(0, 0, 255, 255);
const RGBA8 RGBA8::kYellow = RGBA8(255, 255, 0, 255);
const RGBA8 RGBA8::kWhite = RGBA8(255, 255, 255, 255);

const DawnTestParam D3D12Backend(wgpu::BackendType::D3D12);
const DawnTestParam MetalBackend(wgpu::BackendType::Metal);
const DawnTestParam OpenGLBackend(wgpu::BackendType::OpenGL);
const DawnTestParam VulkanBackend(wgpu::BackendType::Vulkan);

DawnTestParam ForceToggles(const DawnTestParam& originParam,
                           std::initializer_list<const char*> forceEnabledWorkarounds,
                           std::initializer_list<const char*> forceDisabledWorkarounds) {
    DawnTestParam newTestParam = originParam;
    newTestParam.forceEnabledWorkarounds = forceEnabledWorkarounds;
    newTestParam.forceDisabledWorkarounds = forceDisabledWorkarounds;
    return newTestParam;
}

std::ostream& operator<<(std::ostream& os, const DawnTestParam& param) {
    os << ParamName(param.backendType);
    for (const char* forceEnabledWorkaround : param.forceEnabledWorkarounds) {
        os << "__e_" << forceEnabledWorkaround;
    }
    for (const char* forceDisabledWorkaround : param.forceDisabledWorkarounds) {
        os << "__d_" << forceDisabledWorkaround;
    }
    return os;
}

// Implementation of DawnTestEnvironment

void InitDawnEnd2EndTestEnvironment(int argc, char** argv) {
    gTestEnv = new DawnTestEnvironment(argc, argv);
    testing::AddGlobalTestEnvironment(gTestEnv);
}

DawnTestEnvironment::DawnTestEnvironment(int argc, char** argv) {
    for (int i = 1; i < argc; ++i) {
        if (strcmp("-w", argv[i]) == 0 || strcmp("--use-wire", argv[i]) == 0) {
            mUseWire = true;
            continue;
        }

        if (strcmp("-d", argv[i]) == 0 || strcmp("--enable-backend-validation", argv[i]) == 0) {
            mEnableBackendValidation = true;
            continue;
        }

        if (strcmp("-c", argv[i]) == 0 || strcmp("--begin-capture-on-startup", argv[i]) == 0) {
            mBeginCaptureOnStartup = true;
            continue;
        }

        if (strcmp("--skip-validation", argv[i]) == 0) {
            mSkipDawnValidation = true;
            continue;
        }

        if (strcmp("--use-spvc", argv[i]) == 0) {
            mUseSpvc = true;
            continue;
        }

        if (strcmp("--use-spvc-parser", argv[i]) == 0) {
            mUseSpvc = true;  // It's impossible to use the spvc parser without using spvc, so
                              // turning on mUseSpvc implicitly.
            mUseSpvcParser = true;
            continue;
        }

        constexpr const char kVendorIdFilterArg[] = "--adapter-vendor-id=";
        if (strstr(argv[i], kVendorIdFilterArg) == argv[i]) {
            const char* vendorIdFilter = argv[i] + strlen(kVendorIdFilterArg);
            if (vendorIdFilter[0] != '\0') {
                mVendorIdFilter = strtoul(vendorIdFilter, nullptr, 16);
                // Set filter flag if vendor id is non-zero.
                mHasVendorIdFilter = mVendorIdFilter != 0;
            }
            continue;
        }

        constexpr const char kWireTraceDirArg[] = "--wire-trace-dir=";
        if (strstr(argv[i], kWireTraceDirArg) == argv[i]) {
            const char* wireTraceDir = argv[i] + strlen(kWireTraceDirArg);
            if (wireTraceDir[0] != '\0') {
                const char* sep = GetPathSeparator();
                mWireTraceDir = wireTraceDir;
                if (mWireTraceDir.back() != *sep) {
                    mWireTraceDir += sep;
                }
            }
            continue;
        }

        if (strcmp("-h", argv[i]) == 0 || strcmp("--help", argv[i]) == 0) {
            dawn::InfoLog()
                << "\n\nUsage: " << argv[0]
                << " [GTEST_FLAGS...] [-w] [-d] [-c] [--adapter-vendor-id=x]\n"
                   "  -w, --use-wire: Run the tests through the wire (defaults to no wire)\n"
                   "  -d, --enable-backend-validation: Enable backend validation (defaults"
                   " to disabled)\n"
                   "  -c, --begin-capture-on-startup: Begin debug capture on startup "
                   "(defaults to no capture)\n"
                   "  --skip-validation: Skip Dawn validation\n"
                   "  --use-spvc: Use spvc for accessing spirv-cross\n"
                   "  --adapter-vendor-id: Select adapter by vendor id to run end2end tests"
                   "on multi-GPU systems \n";
            continue;
        }
    }
}

// static
void DawnTestEnvironment::SetEnvironment(DawnTestEnvironment* env) {
    gTestEnv = env;
}

void DawnTestEnvironment::SetUp() {
    mInstance = std::make_unique<dawn_native::Instance>();
    mInstance->EnableBackendValidation(mEnableBackendValidation);
    mInstance->EnableBeginCaptureOnStartup(mBeginCaptureOnStartup);

    mInstance.get()->DiscoverDefaultAdapters();
    DiscoverOpenGLAdapter();

    dawn::InfoLog() << "Testing configuration\n"
                       "---------------------\n"
                       "UseWire: "
                    << (mUseWire ? "true" : "false")
                    << "\n"
                       "EnableBackendValidation: "
                    << (mEnableBackendValidation ? "true" : "false")
                    << "\n"
                       "SkipDawnValidation: "
                    << (mSkipDawnValidation ? "true" : "false")
                    << "\n"
                       "UseSpvc: "
                    << (mUseSpvc ? "true" : "false")
                    << "\n"
                       "UseSpvcParser: "
                    << (mUseSpvcParser ? "true" : "false")
                    << "\n"
                       "BeginCaptureOnStartup: "
                    << (mBeginCaptureOnStartup ? "true" : "false")
                    << "\n"
                       "\n"
                    << "System adapters: \n";
    for (const dawn_native::Adapter& adapter : mInstance->GetAdapters()) {
        wgpu::AdapterProperties properties;
        adapter.GetProperties(&properties);

        std::ostringstream vendorId;
        std::ostringstream deviceId;
        vendorId << std::setfill('0') << std::uppercase << std::internal << std::hex << std::setw(4)
                 << properties.vendorID;
        deviceId << std::setfill('0') << std::uppercase << std::internal << std::hex << std::setw(4)
                 << properties.deviceID;

        // Preparing for outputting hex numbers
        dawn::InfoLog() << std::showbase << std::hex << std::setfill('0') << std::setw(4)

                        << " - \"" << properties.name << "\"\n"
                        << "   type: " << AdapterTypeName(properties.adapterType)
                        << ", backend: " << ParamName(properties.backendType) << "\n"
                        << "   vendorId: 0x" << vendorId.str() << ", deviceId: 0x" << deviceId.str()
                        << (mHasVendorIdFilter && mVendorIdFilter == properties.vendorID
                                ? " [Selected]"
                                : "")
                        << "\n";
    }
}

void DawnTestEnvironment::TearDown() {
    // When Vulkan validation layers are enabled, it's unsafe to call Vulkan APIs in the destructor
    // of a static/global variable, so the instance must be manually released beforehand.
    mInstance.reset();
}

bool DawnTestEnvironment::UsesWire() const {
    return mUseWire;
}

bool DawnTestEnvironment::IsBackendValidationEnabled() const {
    return mEnableBackendValidation;
}

bool DawnTestEnvironment::IsDawnValidationSkipped() const {
    return mSkipDawnValidation;
}

bool DawnTestEnvironment::IsSpvcBeingUsed() const {
    return mUseSpvc;
}

bool DawnTestEnvironment::IsSpvcParserBeingUsed() const {
    return mUseSpvcParser;
}

dawn_native::Instance* DawnTestEnvironment::GetInstance() const {
    return mInstance.get();
}

bool DawnTestEnvironment::HasVendorIdFilter() const {
    return mHasVendorIdFilter;
}

uint32_t DawnTestEnvironment::GetVendorIdFilter() const {
    return mVendorIdFilter;
}

const char* DawnTestEnvironment::GetWireTraceDir() const {
    if (mWireTraceDir.length() == 0) {
        return nullptr;
    }
    return mWireTraceDir.c_str();
}

void DawnTestEnvironment::DiscoverOpenGLAdapter() {
#ifdef DAWN_ENABLE_BACKEND_OPENGL
    if (!glfwInit()) {
        return;
    }
    glfwDefaultWindowHints();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 4);
    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GLFW_TRUE);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    std::string windowName = "Dawn OpenGL test window";
    GLFWwindow* window = glfwCreateWindow(400, 400, windowName.c_str(), nullptr, nullptr);

    glfwMakeContextCurrent(window);
    dawn_native::opengl::AdapterDiscoveryOptions adapterOptions;
    adapterOptions.getProc = reinterpret_cast<void* (*)(const char*)>(glfwGetProcAddress);
    mInstance->DiscoverAdapters(&adapterOptions);
#endif  // DAWN_ENABLE_BACKEND_OPENGL
}

class WireServerTraceLayer : public dawn_wire::CommandHandler {
  public:
    WireServerTraceLayer(const char* file, dawn_wire::CommandHandler* handler)
        : dawn_wire::CommandHandler(), mHandler(handler) {
        mFile.open(file, std::ios_base::out | std::ios_base::binary | std::ios_base::trunc);
    }

    const volatile char* HandleCommands(const volatile char* commands, size_t size) override {
        mFile.write(const_cast<const char*>(commands), size);
        return mHandler->HandleCommands(commands, size);
    }

  private:
    dawn_wire::CommandHandler* mHandler;
    std::ofstream mFile;
};

// Implementation of DawnTest

DawnTestBase::DawnTestBase(const DawnTestParam& param) : mParam(param) {
}

DawnTestBase::~DawnTestBase() {
    // We need to destroy child objects before the Device
    mReadbackSlots.clear();
    queue = wgpu::Queue();
    device = wgpu::Device();

    mWireClient = nullptr;
    mWireServer = nullptr;
    if (gTestEnv->UsesWire()) {
        backendProcs.deviceRelease(backendDevice);
    }

    dawnProcSetProcs(nullptr);
}

bool DawnTestBase::IsD3D12() const {
    return mParam.backendType == wgpu::BackendType::D3D12;
}

bool DawnTestBase::IsMetal() const {
    return mParam.backendType == wgpu::BackendType::Metal;
}

bool DawnTestBase::IsOpenGL() const {
    return mParam.backendType == wgpu::BackendType::OpenGL;
}

bool DawnTestBase::IsVulkan() const {
    return mParam.backendType == wgpu::BackendType::Vulkan;
}

bool DawnTestBase::IsAMD() const {
    return gpu_info::IsAMD(mAdapterProperties.vendorID);
}

bool DawnTestBase::IsARM() const {
    return gpu_info::IsARM(mAdapterProperties.vendorID);
}

bool DawnTestBase::IsImgTec() const {
    return gpu_info::IsImgTec(mAdapterProperties.vendorID);
}

bool DawnTestBase::IsIntel() const {
    return gpu_info::IsIntel(mAdapterProperties.vendorID);
}

bool DawnTestBase::IsNvidia() const {
    return gpu_info::IsNvidia(mAdapterProperties.vendorID);
}

bool DawnTestBase::IsQualcomm() const {
    return gpu_info::IsQualcomm(mAdapterProperties.vendorID);
}

bool DawnTestBase::IsWindows() const {
#ifdef DAWN_PLATFORM_WINDOWS
    return true;
#else
    return false;
#endif
}

bool DawnTestBase::IsLinux() const {
#ifdef DAWN_PLATFORM_LINUX
    return true;
#else
    return false;
#endif
}

bool DawnTestBase::IsMacOS() const {
#ifdef DAWN_PLATFORM_APPLE
    return true;
#else
    return false;
#endif
}

bool DawnTestBase::UsesWire() const {
    return gTestEnv->UsesWire();
}

bool DawnTestBase::IsBackendValidationEnabled() const {
    return gTestEnv->IsBackendValidationEnabled();
}

bool DawnTestBase::IsDawnValidationSkipped() const {
    return gTestEnv->IsDawnValidationSkipped();
}

bool DawnTestBase::IsSpvcBeingUsed() const {
    return gTestEnv->IsSpvcBeingUsed();
}

bool DawnTestBase::HasVendorIdFilter() const {
    return gTestEnv->HasVendorIdFilter();
}

uint32_t DawnTestBase::GetVendorIdFilter() const {
    return gTestEnv->GetVendorIdFilter();
}

std::vector<const char*> DawnTestBase::GetRequiredExtensions() {
    return {};
}

const wgpu::AdapterProperties& DawnTestBase::GetAdapterProperties() const {
    return mAdapterProperties;
}

// This function can only be called after SetUp() because it requires mBackendAdapter to be
// initialized.
bool DawnTestBase::SupportsExtensions(const std::vector<const char*>& extensions) {
    ASSERT(mBackendAdapter);

    std::set<std::string> supportedExtensionsSet;
    for (const char* supportedExtensionName : mBackendAdapter.GetSupportedExtensions()) {
        supportedExtensionsSet.insert(supportedExtensionName);
    }

    for (const char* extensionName : extensions) {
        if (supportedExtensionsSet.find(extensionName) == supportedExtensionsSet.end()) {
            return false;
        }
    }

    return true;
}

void DawnTestBase::SetUp() {
    // Initialize mBackendAdapter, and create the device.
    const wgpu::BackendType backendType = mParam.backendType;
    {
        dawn_native::Instance* instance = gTestEnv->GetInstance();
        std::vector<dawn_native::Adapter> adapters = instance->GetAdapters();

        for (const dawn_native::Adapter& adapter : adapters) {
            wgpu::AdapterProperties properties;
            adapter.GetProperties(&properties);

            if (properties.backendType == backendType) {
                if (properties.adapterType == wgpu::AdapterType::CPU) {
                    continue;
                }

                // Filter adapter by vendor id
                if (HasVendorIdFilter()) {
                    if (properties.vendorID == GetVendorIdFilter()) {
                        mBackendAdapter = adapter;
                        break;
                    }
                    continue;
                }

                // Prefer discrete GPU on multi-GPU systems, otherwise get integrated GPU.
                mBackendAdapter = adapter;
                mAdapterProperties = properties;
                if (properties.adapterType == wgpu::AdapterType::DiscreteGPU) {
                    break;
                }
            }
        }

        if (!mBackendAdapter) {
            return;
        }
    }

    for (const char* forceEnabledWorkaround : mParam.forceEnabledWorkarounds) {
        ASSERT(gTestEnv->GetInstance()->GetToggleInfo(forceEnabledWorkaround) != nullptr);
    }
    for (const char* forceDisabledWorkaround : mParam.forceDisabledWorkarounds) {
        ASSERT(gTestEnv->GetInstance()->GetToggleInfo(forceDisabledWorkaround) != nullptr);
    }
    dawn_native::DeviceDescriptor deviceDescriptor;
    deviceDescriptor.forceEnabledToggles = mParam.forceEnabledWorkarounds;
    deviceDescriptor.forceDisabledToggles = mParam.forceDisabledWorkarounds;
    deviceDescriptor.requiredExtensions = GetRequiredExtensions();

    static constexpr char kSkipValidationToggle[] = "skip_validation";
    if (gTestEnv->IsDawnValidationSkipped()) {
        ASSERT(gTestEnv->GetInstance()->GetToggleInfo(kSkipValidationToggle) != nullptr);
        deviceDescriptor.forceEnabledToggles.push_back(kSkipValidationToggle);
    }

    static constexpr char kUseSpvcToggle[] = "use_spvc";
    static constexpr char kUseSpvcParserToggle[] = "use_spvc_parser";
    if (gTestEnv->IsSpvcBeingUsed()) {
        ASSERT(gTestEnv->GetInstance()->GetToggleInfo(kUseSpvcToggle) != nullptr);
        deviceDescriptor.forceEnabledToggles.push_back(kUseSpvcToggle);

        if (gTestEnv->IsSpvcParserBeingUsed()) {
            ASSERT(gTestEnv->GetInstance()->GetToggleInfo(kUseSpvcParserToggle) != nullptr);
            deviceDescriptor.forceEnabledToggles.push_back(kUseSpvcParserToggle);
        }

    } else {
        // Turning on spvc parser should always turn on spvc.
        ASSERT(!gTestEnv->IsSpvcParserBeingUsed());
        ASSERT(gTestEnv->GetInstance()->GetToggleInfo(kUseSpvcToggle) != nullptr);
        deviceDescriptor.forceDisabledToggles.push_back(kUseSpvcToggle);
    }

    backendDevice = mBackendAdapter.CreateDevice(&deviceDescriptor);
    ASSERT_NE(nullptr, backendDevice);

    backendProcs = dawn_native::GetProcs();

    // Choose whether to use the backend procs and devices directly, or set up the wire.
    WGPUDevice cDevice = nullptr;
    DawnProcTable procs;

    if (gTestEnv->UsesWire()) {
        mC2sBuf = std::make_unique<utils::TerribleCommandBuffer>();
        mS2cBuf = std::make_unique<utils::TerribleCommandBuffer>();

        dawn_wire::WireServerDescriptor serverDesc = {};
        serverDesc.device = backendDevice;
        serverDesc.procs = &backendProcs;
        serverDesc.serializer = mS2cBuf.get();

        mWireServer.reset(new dawn_wire::WireServer(serverDesc));
        mC2sBuf->SetHandler(mWireServer.get());

        if (gTestEnv->GetWireTraceDir() != nullptr) {
            std::string file =
                std::string(
                    ::testing::UnitTest::GetInstance()->current_test_info()->test_suite_name()) +
                "_" + ::testing::UnitTest::GetInstance()->current_test_info()->name();
            // Replace slashes in gtest names with underscores so everything is in one directory.
            std::replace(file.begin(), file.end(), '/', '_');

            std::string fullPath = gTestEnv->GetWireTraceDir() + file;

            mWireServerTraceLayer.reset(
                new WireServerTraceLayer(fullPath.c_str(), mWireServer.get()));
            mC2sBuf->SetHandler(mWireServerTraceLayer.get());
        }

        dawn_wire::WireClientDescriptor clientDesc = {};
        clientDesc.serializer = mC2sBuf.get();

        mWireClient.reset(new dawn_wire::WireClient(clientDesc));
        WGPUDevice clientDevice = mWireClient->GetDevice();
        DawnProcTable clientProcs = dawn_wire::WireClient::GetProcs();
        mS2cBuf->SetHandler(mWireClient.get());

        procs = clientProcs;
        cDevice = clientDevice;
    } else {
        procs = backendProcs;
        cDevice = backendDevice;
    }

    // Set up the device and queue because all tests need them, and DawnTestBase needs them too for
    // the deferred expectations.
    dawnProcSetProcs(&procs);
    device = wgpu::Device::Acquire(cDevice);
    queue = device.CreateQueue();

    device.SetUncapturedErrorCallback(OnDeviceError, this);
    device.SetDeviceLostCallback(OnDeviceLost, this);
}

void DawnTestBase::TearDown() {
    FlushWire();

    MapSlotsSynchronously();
    ResolveExpectations();

    for (size_t i = 0; i < mReadbackSlots.size(); ++i) {
        mReadbackSlots[i].buffer.Unmap();
    }
}

bool DawnTestBase::HasAdapter() const {
    return !!mBackendAdapter;
}

void DawnTestBase::StartExpectDeviceError() {
    mExpectError = true;
    mError = false;
}
bool DawnTestBase::EndExpectDeviceError() {
    mExpectError = false;
    return mError;
}

// static
void DawnTestBase::OnDeviceError(WGPUErrorType type, const char* message, void* userdata) {
    ASSERT(type != WGPUErrorType_NoError);
    DawnTestBase* self = static_cast<DawnTestBase*>(userdata);

    ASSERT_TRUE(self->mExpectError) << "Got unexpected device error: " << message;
    ASSERT_FALSE(self->mError) << "Got two errors in expect block";
    self->mError = true;
}

void DawnTestBase::OnDeviceLost(const char* message, void* userdata) {
    FAIL() << "Device Lost during test: " << message;
}

std::ostringstream& DawnTestBase::AddBufferExpectation(const char* file,
                                                       int line,
                                                       const wgpu::Buffer& buffer,
                                                       uint64_t offset,
                                                       uint64_t size,
                                                       detail::Expectation* expectation) {
    auto readback = ReserveReadback(size);

    // We need to enqueue the copy immediately because by the time we resolve the expectation,
    // the buffer might have been modified.
    wgpu::CommandEncoder encoder = device.CreateCommandEncoder();
    encoder.CopyBufferToBuffer(buffer, offset, readback.buffer, readback.offset, size);

    wgpu::CommandBuffer commands = encoder.Finish();
    queue.Submit(1, &commands);

    DeferredExpectation deferred;
    deferred.file = file;
    deferred.line = line;
    deferred.readbackSlot = readback.slot;
    deferred.readbackOffset = readback.offset;
    deferred.size = size;
    deferred.rowBytes = size;
    deferred.rowPitch = size;
    deferred.expectation.reset(expectation);

    mDeferredExpectations.push_back(std::move(deferred));
    mDeferredExpectations.back().message = std::make_unique<std::ostringstream>();
    return *(mDeferredExpectations.back().message.get());
}

std::ostringstream& DawnTestBase::AddTextureExpectation(const char* file,
                                                        int line,
                                                        const wgpu::Texture& texture,
                                                        uint32_t x,
                                                        uint32_t y,
                                                        uint32_t width,
                                                        uint32_t height,
                                                        uint32_t level,
                                                        uint32_t slice,
                                                        uint32_t pixelSize,
                                                        detail::Expectation* expectation) {
    uint32_t rowPitch = Align(width * pixelSize, kTextureRowPitchAlignment);
    uint32_t size = rowPitch * (height - 1) + width * pixelSize;

    auto readback = ReserveReadback(size);

    // We need to enqueue the copy immediately because by the time we resolve the expectation,
    // the texture might have been modified.
    wgpu::TextureCopyView textureCopyView =
        utils::CreateTextureCopyView(texture, level, slice, {x, y, 0});
    wgpu::BufferCopyView bufferCopyView =
        utils::CreateBufferCopyView(readback.buffer, readback.offset, rowPitch, 0);
    wgpu::Extent3D copySize = {width, height, 1};

    wgpu::CommandEncoder encoder = device.CreateCommandEncoder();
    encoder.CopyTextureToBuffer(&textureCopyView, &bufferCopyView, &copySize);

    wgpu::CommandBuffer commands = encoder.Finish();
    queue.Submit(1, &commands);

    DeferredExpectation deferred;
    deferred.file = file;
    deferred.line = line;
    deferred.readbackSlot = readback.slot;
    deferred.readbackOffset = readback.offset;
    deferred.size = size;
    deferred.rowBytes = width * pixelSize;
    deferred.rowPitch = rowPitch;
    deferred.expectation.reset(expectation);

    mDeferredExpectations.push_back(std::move(deferred));
    mDeferredExpectations.back().message = std::make_unique<std::ostringstream>();
    return *(mDeferredExpectations.back().message.get());
}

void DawnTestBase::WaitABit() {
    device.Tick();
    FlushWire();

    utils::USleep(100);
}

void DawnTestBase::FlushWire() {
    if (gTestEnv->UsesWire()) {
        bool C2SFlushed = mC2sBuf->Flush();
        bool S2CFlushed = mS2cBuf->Flush();
        ASSERT(C2SFlushed);
        ASSERT(S2CFlushed);
    }
}

DawnTestBase::ReadbackReservation DawnTestBase::ReserveReadback(uint64_t readbackSize) {
    // For now create a new MapRead buffer for each readback
    // TODO(cwallez@chromium.org): eventually make bigger buffers and allocate linearly?
    wgpu::BufferDescriptor descriptor;
    descriptor.size = readbackSize;
    descriptor.usage = wgpu::BufferUsage::MapRead | wgpu::BufferUsage::CopyDst;

    ReadbackSlot slot;
    slot.bufferSize = readbackSize;
    slot.buffer = device.CreateBuffer(&descriptor);

    ReadbackReservation reservation;
    reservation.buffer = slot.buffer;
    reservation.slot = mReadbackSlots.size();
    reservation.offset = 0;

    mReadbackSlots.push_back(std::move(slot));
    return reservation;
}

void DawnTestBase::MapSlotsSynchronously() {
    // Initialize numPendingMapOperations before mapping, just in case the callback is called
    // immediately.
    mNumPendingMapOperations = mReadbackSlots.size();

    // Map all readback slots
    for (size_t i = 0; i < mReadbackSlots.size(); ++i) {
        MapReadUserdata* userdata = new MapReadUserdata{this, i};

        auto& slot = mReadbackSlots[i];
        slot.buffer.MapReadAsync(SlotMapReadCallback, userdata);
    }

    // Busy wait until all map operations are done.
    while (mNumPendingMapOperations != 0) {
        WaitABit();
    }
}

// static
void DawnTestBase::SlotMapReadCallback(WGPUBufferMapAsyncStatus status,
                                       const void* data,
                                       uint64_t,
                                       void* userdata_) {
    DAWN_ASSERT(status == WGPUBufferMapAsyncStatus_Success);

    auto userdata = static_cast<MapReadUserdata*>(userdata_);
    userdata->test->mReadbackSlots[userdata->slot].mappedData = data;
    userdata->test->mNumPendingMapOperations--;

    delete userdata;
}

void DawnTestBase::ResolveExpectations() {
    for (const auto& expectation : mDeferredExpectations) {
        DAWN_ASSERT(mReadbackSlots[expectation.readbackSlot].mappedData != nullptr);

        // Get a pointer to the mapped copy of the data for the expectation.
        const char* data =
            static_cast<const char*>(mReadbackSlots[expectation.readbackSlot].mappedData);
        data += expectation.readbackOffset;

        uint32_t size;
        std::vector<char> packedData;
        if (expectation.rowBytes != expectation.rowPitch) {
            DAWN_ASSERT(expectation.rowPitch > expectation.rowBytes);
            uint32_t rowCount =
                (expectation.size + expectation.rowPitch - 1) / expectation.rowPitch;
            uint32_t packedSize = rowCount * expectation.rowBytes;
            packedData.resize(packedSize);
            for (uint32_t r = 0; r < rowCount; ++r) {
                for (uint32_t i = 0; i < expectation.rowBytes; ++i) {
                    packedData[i + r * expectation.rowBytes] = data[i + r * expectation.rowPitch];
                }
            }
            data = packedData.data();
            size = packedSize;
        } else {
            size = expectation.size;
        }

        // Get the result for the expectation and add context to failures
        testing::AssertionResult result = expectation.expectation->Check(data, size);
        if (!result) {
            result << " Expectation created at " << expectation.file << ":" << expectation.line
                   << std::endl;
            result << expectation.message->str();
        }

        EXPECT_TRUE(result);
    }
}

bool RGBA8::operator==(const RGBA8& other) const {
    return r == other.r && g == other.g && b == other.b && a == other.a;
}

bool RGBA8::operator!=(const RGBA8& other) const {
    return !(*this == other);
}

std::ostream& operator<<(std::ostream& stream, const RGBA8& color) {
    return stream << "RGBA8(" << static_cast<int>(color.r) << ", " << static_cast<int>(color.g)
                  << ", " << static_cast<int>(color.b) << ", " << static_cast<int>(color.a) << ")";
}

namespace detail {
    bool IsBackendAvailable(wgpu::BackendType type) {
        switch (type) {
#if defined(DAWN_ENABLE_BACKEND_D3D12)
            case wgpu::BackendType::D3D12:
#endif
#if defined(DAWN_ENABLE_BACKEND_METAL)
            case wgpu::BackendType::Metal:
#endif
#if defined(DAWN_ENABLE_BACKEND_OPENGL)
            case wgpu::BackendType::OpenGL:
#endif
#if defined(DAWN_ENABLE_BACKEND_VULKAN)
            case wgpu::BackendType::Vulkan:
#endif
                return true;

            default:
                return false;
        }
    }

    std::vector<DawnTestParam> FilterBackends(const DawnTestParam* params, size_t numParams) {
        std::vector<DawnTestParam> backends;

        for (size_t i = 0; i < numParams; ++i) {
            if (IsBackendAvailable(params[i].backendType)) {
                backends.push_back(params[i]);
            }
        }
        return backends;
    }

    // Helper classes to set expectations

    template <typename T>
    ExpectEq<T>::ExpectEq(T singleValue) {
        mExpected.push_back(singleValue);
    }

    template <typename T>
    ExpectEq<T>::ExpectEq(const T* values, const unsigned int count) {
        mExpected.assign(values, values + count);
    }

    template <typename T>
    testing::AssertionResult ExpectEq<T>::Check(const void* data, size_t size) {
        DAWN_ASSERT(size == sizeof(T) * mExpected.size());

        const T* actual = static_cast<const T*>(data);

        for (size_t i = 0; i < mExpected.size(); ++i) {
            if (actual[i] != mExpected[i]) {
                testing::AssertionResult result = testing::AssertionFailure()
                                                  << "Expected data[" << i << "] to be "
                                                  << mExpected[i] << ", actual " << actual[i]
                                                  << std::endl;

                auto printBuffer = [&](const T* buffer) {
                    static constexpr unsigned int kBytes = sizeof(T);

                    for (size_t index = 0; index < mExpected.size(); ++index) {
                        auto byteView = reinterpret_cast<const uint8_t*>(buffer + index);
                        for (unsigned int b = 0; b < kBytes; ++b) {
                            char buf[4];
                            sprintf(buf, "%02X ", byteView[b]);
                            result << buf;
                        }
                    }
                    result << std::endl;
                };

                if (mExpected.size() <= 1024) {
                    result << "Expected:" << std::endl;
                    printBuffer(mExpected.data());

                    result << "Actual:" << std::endl;
                    printBuffer(actual);
                }

                return result;
            }
        }

        return testing::AssertionSuccess();
    }

    template class ExpectEq<uint8_t>;
    template class ExpectEq<uint32_t>;
    template class ExpectEq<RGBA8>;
    template class ExpectEq<float>;
}  // namespace detail