/*
 * Copyright 2011 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "GrContext.h"
#include "GrBackendSemaphore.h"
#include "GrClip.h"
#include "GrContextOptions.h"
#include "GrContextPriv.h"
#include "GrDrawingManager.h"
#include "GrGpu.h"
#include "GrProxyProvider.h"
#include "GrRenderTargetContext.h"
#include "GrRenderTargetProxy.h"
#include "GrResourceCache.h"
#include "GrResourceProvider.h"
#include "GrSemaphore.h"
#include "GrSoftwarePathRenderer.h"
#include "GrSurfaceContext.h"
#include "GrSurfacePriv.h"
#include "GrSurfaceProxyPriv.h"
#include "GrTexture.h"
#include "GrTextureContext.h"
#include "GrTextureStripAtlas.h"
#include "GrTracing.h"
#include "SkAutoPixmapStorage.h"
#include "SkConvertPixels.h"
#include "SkDeferredDisplayList.h"
#include "SkGr.h"
#include "SkImageInfoPriv.h"
#include "SkJSONWriter.h"
#include "SkMakeUnique.h"
#include "SkSurface_Gpu.h"
#include "SkTaskGroup.h"
#include "SkUnPreMultiplyPriv.h"
#include "effects/GrConfigConversionEffect.h"
#include "text/GrTextBlobCache.h"

#define ASSERT_OWNED_PROXY(P) \
SkASSERT(!(P) || !((P)->priv().peekTexture()) || (P)->priv().peekTexture()->getContext() == this)
#define ASSERT_OWNED_PROXY_PRIV(P) \
SkASSERT(!(P) || !((P)->priv().peekTexture()) || (P)->priv().peekTexture()->getContext() == fContext)

#define ASSERT_OWNED_RESOURCE(R) SkASSERT(!(R) || (R)->getContext() == this)
#define ASSERT_SINGLE_OWNER \
    SkDEBUGCODE(GrSingleOwner::AutoEnforce debug_SingleOwner(&fSingleOwner);)
#define ASSERT_SINGLE_OWNER_PRIV \
    SkDEBUGCODE(GrSingleOwner::AutoEnforce debug_SingleOwner(&fContext->fSingleOwner);)
#define RETURN_IF_ABANDONED if (fDrawingManager->wasAbandoned()) { return; }
#define RETURN_IF_ABANDONED_PRIV if (fContext->fDrawingManager->wasAbandoned()) { return; }
#define RETURN_FALSE_IF_ABANDONED if (fDrawingManager->wasAbandoned()) { return false; }
#define RETURN_FALSE_IF_ABANDONED_PRIV if (fContext->fDrawingManager->wasAbandoned()) { return false; }
#define RETURN_NULL_IF_ABANDONED if (fDrawingManager->wasAbandoned()) { return nullptr; }

////////////////////////////////////////////////////////////////////////////////

static int32_t gNextID = 1;
static int32_t next_id() {
    int32_t id;
    do {
        id = sk_atomic_inc(&gNextID);
    } while (id == SK_InvalidGenID);
    return id;
}

GrContext::GrContext(GrBackend backend, int32_t id)
        : fBackend(backend)
        , fUniqueID(SK_InvalidGenID == id ? next_id() : id) {
    fResourceCache = nullptr;
    fResourceProvider = nullptr;
    fProxyProvider = nullptr;
    fGlyphCache = nullptr;
}

bool GrContext::initCommon(const GrContextOptions& options) {
    ASSERT_SINGLE_OWNER
    SkASSERT(fCaps);  // needs to have been initialized by derived classes
    SkASSERT(fThreadSafeProxy); // needs to have been initialized by derived classes

    if (fGpu) {
        fCaps = fGpu->refCaps();
        fResourceCache = new GrResourceCache(fCaps.get(), fUniqueID);
        fResourceProvider = new GrResourceProvider(fGpu.get(), fResourceCache, &fSingleOwner,
                                                   options.fExplicitlyAllocateGPUResources);
    }

    fProxyProvider = new GrProxyProvider(fResourceProvider, fResourceCache, fCaps, &fSingleOwner);

    if (fResourceCache) {
        fResourceCache->setProxyProvider(fProxyProvider);
    }

    fTextureStripAtlasManager.reset(new GrTextureStripAtlasManager);

    fDisableGpuYUVConversion = options.fDisableGpuYUVConversion;
    fSharpenMipmappedTextures = options.fSharpenMipmappedTextures;
    fDidTestPMConversions = false;

    GrPathRendererChain::Options prcOptions;
    prcOptions.fAllowPathMaskCaching = options.fAllowPathMaskCaching;
#if GR_TEST_UTILS
    prcOptions.fGpuPathRenderers = options.fGpuPathRenderers;
#endif
    if (options.fDisableDistanceFieldPaths) {
        prcOptions.fGpuPathRenderers &= ~GpuPathRenderers::kSmall;
    }

    if (!fResourceCache) {
        // DDL TODO: remove this crippling of the path renderer chain
        // Disable the small path renderer bc of the proxies in the atlas. They need to be
        // unified when the opLists are added back to the destination drawing manager.
        prcOptions.fGpuPathRenderers &= ~GpuPathRenderers::kSmall;
        prcOptions.fGpuPathRenderers &= ~GpuPathRenderers::kCoverageCounting;
    }

    GrAtlasTextContext::Options atlasTextContextOptions;
    atlasTextContextOptions.fMaxDistanceFieldFontSize = options.fGlyphsAsPathsFontSize;
    atlasTextContextOptions.fMinDistanceFieldFontSize = options.fMinDistanceFieldFontSize;
    atlasTextContextOptions.fDistanceFieldVerticesAlwaysHaveW = false;
#if SK_SUPPORT_ATLAS_TEXT
    if (GrContextOptions::Enable::kYes == options.fDistanceFieldGlyphVerticesAlwaysHaveW) {
        atlasTextContextOptions.fDistanceFieldVerticesAlwaysHaveW = true;
    }
#endif

    bool explicitlyAllocatingResources = fResourceProvider
                                            ? fResourceProvider->explicitlyAllocateGPUResources()
                                            : false;
    fDrawingManager.reset(new GrDrawingManager(this, prcOptions, atlasTextContextOptions,
                                               &fSingleOwner, explicitlyAllocatingResources,
                                               options.fSortRenderTargets));

    fGlyphCache = new GrGlyphCache(fCaps.get(), options.fGlyphCacheTextureMaximumBytes);

    fTextBlobCache.reset(new GrTextBlobCache(TextBlobCacheOverBudgetCB,
                                             this, this->uniqueID(), SkToBool(fGpu)));

    // DDL TODO: we need to think through how the task group & persistent cache
    // get passed on to/shared between all the DDLRecorders created with this context.
    if (options.fExecutor) {
        fTaskGroup = skstd::make_unique<SkTaskGroup>(*options.fExecutor);
    }

    fPersistentCache = options.fPersistentCache;

    return true;
}

GrContext::~GrContext() {
    ASSERT_SINGLE_OWNER

    if (fDrawingManager) {
        fDrawingManager->cleanup();
    }

    fTextureStripAtlasManager = nullptr;
    delete fResourceProvider;
    delete fResourceCache;
    delete fProxyProvider;
    delete fGlyphCache;
}

sk_sp<GrContextThreadSafeProxy> GrContext::threadSafeProxy() {
    return fThreadSafeProxy;
}

SkSurfaceCharacterization GrContextThreadSafeProxy::createCharacterization(
                                     size_t cacheMaxResourceBytes,
                                     const SkImageInfo& ii, const GrBackendFormat& backendFormat,
                                     int sampleCnt, GrSurfaceOrigin origin,
                                     const SkSurfaceProps& surfaceProps,
                                     bool isMipMapped) {
    if (!backendFormat.isValid()) {
        return SkSurfaceCharacterization(); // return an invalid characterization
    }

    if (!fCaps->mipMapSupport()) {
        isMipMapped = false;
    }

    GrPixelConfig config = kUnknown_GrPixelConfig;
    if (!fCaps->getConfigFromBackendFormat(backendFormat, ii.colorType(), &config)) {
        return SkSurfaceCharacterization(); // return an invalid characterization
    }

    if (!SkSurface_Gpu::Valid(fCaps.get(), config, ii.colorSpace())) {
        return SkSurfaceCharacterization(); // return an invalid characterization
    }

    sampleCnt = fCaps->getRenderTargetSampleCount(sampleCnt, config);
    if (!sampleCnt) {
        return SkSurfaceCharacterization(); // return an invalid characterization
    }

    GrFSAAType FSAAType = GrFSAAType::kNone;
    if (sampleCnt > 1) {
        FSAAType = fCaps->usesMixedSamples() ? GrFSAAType::kMixedSamples : GrFSAAType::kUnifiedMSAA;
    }

    // This surface characterization factory assumes that the resulting characterization is
    // textureable.
    if (!fCaps->isConfigTexturable(config)) {
        return SkSurfaceCharacterization(); // return an invalid characterization
    }

    return SkSurfaceCharacterization(sk_ref_sp<GrContextThreadSafeProxy>(this),
                                     cacheMaxResourceBytes, ii,
                                     origin, config, FSAAType, sampleCnt,
                                     SkSurfaceCharacterization::Textureable(true),
                                     SkSurfaceCharacterization::MipMapped(isMipMapped),
                                     surfaceProps);
}

void GrContext::abandonContext() {
    ASSERT_SINGLE_OWNER

    fTextureStripAtlasManager->abandon();
    fProxyProvider->abandon();
    fResourceProvider->abandon();

    // Need to abandon the drawing manager first so all the render targets
    // will be released/forgotten before they too are abandoned.
    fDrawingManager->abandon();

    // abandon first to so destructors
    // don't try to free the resources in the API.
    fResourceCache->abandonAll();

    fGpu->disconnect(GrGpu::DisconnectType::kAbandon);

    fGlyphCache->freeAll();
    fTextBlobCache->freeAll();
}

void GrContext::releaseResourcesAndAbandonContext() {
    ASSERT_SINGLE_OWNER

    fTextureStripAtlasManager->abandon();
    fProxyProvider->abandon();
    fResourceProvider->abandon();

    // Need to abandon the drawing manager first so all the render targets
    // will be released/forgotten before they too are abandoned.
    fDrawingManager->abandon();

    // Release all resources in the backend 3D API.
    fResourceCache->releaseAll();

    fGpu->disconnect(GrGpu::DisconnectType::kCleanup);

    fGlyphCache->freeAll();
    fTextBlobCache->freeAll();
}

void GrContext::resetContext(uint32_t state) {
    ASSERT_SINGLE_OWNER
    fGpu->markContextDirty(state);
}

void GrContext::freeGpuResources() {
    ASSERT_SINGLE_OWNER

    fGlyphCache->freeAll();

    fDrawingManager->freeGpuResources();

    fResourceCache->purgeAllUnlocked();
}

void GrContext::purgeUnlockedResources(bool scratchResourcesOnly) {
    ASSERT_SINGLE_OWNER
    fResourceCache->purgeUnlockedResources(scratchResourcesOnly);
    fResourceCache->purgeAsNeeded();
    fTextBlobCache->purgeStaleBlobs();
}

void GrContext::performDeferredCleanup(std::chrono::milliseconds msNotUsed) {
    ASSERT_SINGLE_OWNER
    fResourceCache->purgeAsNeeded();
    fResourceCache->purgeResourcesNotUsedSince(GrStdSteadyClock::now() - msNotUsed);

    fTextBlobCache->purgeStaleBlobs();
}

void GrContext::purgeUnlockedResources(size_t bytesToPurge, bool preferScratchResources) {
    ASSERT_SINGLE_OWNER
    fResourceCache->purgeUnlockedResources(bytesToPurge, preferScratchResources);
}

void GrContext::getResourceCacheUsage(int* resourceCount, size_t* resourceBytes) const {
    ASSERT_SINGLE_OWNER

    if (resourceCount) {
        *resourceCount = fResourceCache->getBudgetedResourceCount();
    }
    if (resourceBytes) {
        *resourceBytes = fResourceCache->getBudgetedResourceBytes();
    }
}

size_t GrContext::getResourceCachePurgeableBytes() const {
    ASSERT_SINGLE_OWNER
    return fResourceCache->getPurgeableBytes();
}

////////////////////////////////////////////////////////////////////////////////

int GrContext::maxTextureSize() const { return this->caps()->maxTextureSize(); }

int GrContext::maxRenderTargetSize() const { return this->caps()->maxRenderTargetSize(); }

bool GrContext::colorTypeSupportedAsImage(SkColorType colorType) const {
    GrPixelConfig config = SkImageInfo2GrPixelConfig(colorType, nullptr, *this->caps());
    return this->caps()->isConfigTexturable(config);
}

int GrContext::maxSurfaceSampleCountForColorType(SkColorType colorType) const {
    GrPixelConfig config = SkImageInfo2GrPixelConfig(colorType, nullptr, *this->caps());
    return this->caps()->maxRenderTargetSampleCount(config);
}

////////////////////////////////////////////////////////////////////////////////

void GrContext::TextBlobCacheOverBudgetCB(void* data) {
    SkASSERT(data);
    // TextBlobs are drawn at the SkGpuDevice level, therefore they cannot rely on
    // GrRenderTargetContext to perform a necessary flush.  The solution is to move drawText calls
    // to below the GrContext level, but this is not trivial because they call drawPath on
    // SkGpuDevice.
    GrContext* context = reinterpret_cast<GrContext*>(data);
    context->flush();
}

////////////////////////////////////////////////////////////////////////////////

void GrContext::flush() {
    ASSERT_SINGLE_OWNER
    RETURN_IF_ABANDONED

    fDrawingManager->flush(nullptr);
}

GrSemaphoresSubmitted GrContext::flushAndSignalSemaphores(int numSemaphores,
                                                          GrBackendSemaphore signalSemaphores[]) {
    ASSERT_SINGLE_OWNER
    if (fDrawingManager->wasAbandoned()) { return GrSemaphoresSubmitted::kNo; }

    return fDrawingManager->flush(nullptr, numSemaphores, signalSemaphores);
}

void GrContextPriv::flush(GrSurfaceProxy* proxy) {
    ASSERT_SINGLE_OWNER_PRIV
    RETURN_IF_ABANDONED_PRIV
    ASSERT_OWNED_PROXY_PRIV(proxy);

    fContext->fDrawingManager->flush(proxy);
}

bool sw_convert_to_premul(GrColorType srcColorType, int width, int height, size_t inRowBytes,
                          const void* inPixels, size_t outRowBytes, void* outPixels) {
    SkColorType colorType = GrColorTypeToSkColorType(srcColorType);
    if (kUnknown_SkColorType == colorType || 4 != SkColorTypeBytesPerPixel(colorType)) {
        return false;
    }

    for (int y = 0; y < height; y++) {
        SkOpts::RGBA_to_rgbA((uint32_t*) outPixels, inPixels, width);
        outPixels = SkTAddOffset<void>(outPixels, outRowBytes);
        inPixels = SkTAddOffset<const void>(inPixels, inRowBytes);
    }

    return true;
}

// TODO: This will be removed when GrSurfaceContexts are aware of their color types.
// (skbug.com/6718)
static bool valid_premul_config(GrPixelConfig config) {
    switch (config) {
        case kUnknown_GrPixelConfig:            return false;
        case kAlpha_8_GrPixelConfig:            return false;
        case kGray_8_GrPixelConfig:             return false;
        case kRGB_565_GrPixelConfig:            return false;
        case kRGBA_4444_GrPixelConfig:          return true;
        case kRGBA_8888_GrPixelConfig:          return true;
        case kRGB_888_GrPixelConfig:            return false;
        case kBGRA_8888_GrPixelConfig:          return true;
        case kSRGBA_8888_GrPixelConfig:         return true;
        case kSBGRA_8888_GrPixelConfig:         return true;
        case kRGBA_1010102_GrPixelConfig:       return true;
        case kRGBA_float_GrPixelConfig:         return true;
        case kRG_float_GrPixelConfig:           return false;
        case kAlpha_half_GrPixelConfig:         return false;
        case kRGBA_half_GrPixelConfig:          return true;
        case kAlpha_8_as_Alpha_GrPixelConfig:   return false;
        case kAlpha_8_as_Red_GrPixelConfig:     return false;
        case kAlpha_half_as_Red_GrPixelConfig:  return false;
        case kGray_8_as_Lum_GrPixelConfig:      return false;
        case kGray_8_as_Red_GrPixelConfig:      return false;
    }
    SK_ABORT("Invalid GrPixelConfig");
    return false;
}

static bool valid_premul_color_type(GrColorType ct) {
    switch (ct) {
        case GrColorType::kUnknown:      return false;
        case GrColorType::kAlpha_8:      return false;
        case GrColorType::kRGB_565:      return false;
        case GrColorType::kABGR_4444:    return true;
        case GrColorType::kRGBA_8888:    return true;
        case GrColorType::kRGB_888x:     return false;
        case GrColorType::kBGRA_8888:    return true;
        case GrColorType::kRGBA_1010102: return true;
        case GrColorType::kGray_8:       return false;
        case GrColorType::kAlpha_F16:    return false;
        case GrColorType::kRGBA_F16:     return true;
        case GrColorType::kRG_F32:       return false;
        case GrColorType::kRGBA_F32:     return true;
    }
    SK_ABORT("Invalid GrColorType");
    return false;
}

static bool valid_pixel_conversion(GrColorType cpuColorType, GrPixelConfig gpuConfig,
                                   bool premulConversion) {
    // We only allow premul <-> unpremul conversions for some formats
    if (premulConversion &&
        (!valid_premul_color_type(cpuColorType) || !valid_premul_config(gpuConfig))) {
        return false;
    }
    return true;
}

static bool pm_upm_must_round_trip(GrColorType cpuColorType, const SkColorSpace* cpuColorSpace) {
    return !cpuColorSpace &&
           (GrColorType::kRGBA_8888 == cpuColorType || GrColorType::kBGRA_8888 == cpuColorType);
}

// TODO: This will be removed when GrSurfaceContexts are aware of their color types.
// (skbug.com/6718)
static bool pm_upm_must_round_trip(GrPixelConfig surfaceConfig,
                                   const SkColorSpace* surfaceColorSpace) {
    return !surfaceColorSpace &&
           (kRGBA_8888_GrPixelConfig == surfaceConfig || kBGRA_8888_GrPixelConfig == surfaceConfig);
}

static GrSRGBConversion determine_write_pixels_srgb_conversion(GrColorType srcColorType,
                                                               const SkColorSpace* srcColorSpace,
                                                               GrSRGBEncoded dstSRGBEncoded,
                                                               const SkColorSpace* dstColorSpace,
                                                               const GrCaps& caps) {
    // No support for sRGB-encoded alpha.
    if (GrColorTypeIsAlphaOnly(srcColorType)) {
        return GrSRGBConversion::kNone;
    }
    // No conversions without GPU support for sRGB. (Legacy mode)
    if (!caps.srgbSupport()) {
        return GrSRGBConversion::kNone;
    }
    // If the GrSurfaceContext has no color space then it is in legacy mode.
    if (!dstColorSpace) {
        return GrSRGBConversion::kNone;
    }

    bool srcColorSpaceIsSRGB = srcColorSpace && srcColorSpace->gammaCloseToSRGB();
    bool dstColorSpaceIsSRGB = dstColorSpace->gammaCloseToSRGB();

    // For now we are assuming that if color space of the dst does not have sRGB gamma then the
    // texture format is not sRGB encoded and vice versa. Note that we already checked for "legacy"
    // mode being forced on by caps above. This may change in the future. We will then have to
    // perform shader based conversions.
    SkASSERT(dstColorSpaceIsSRGB == (GrSRGBEncoded::kYes == dstSRGBEncoded));

    if (srcColorSpaceIsSRGB == dstColorSpaceIsSRGB) {
        return GrSRGBConversion::kNone;
    }
    return srcColorSpaceIsSRGB ? GrSRGBConversion::kSRGBToLinear : GrSRGBConversion::kLinearToSRGB;
}

static GrSRGBConversion determine_read_pixels_srgb_conversion(GrSRGBEncoded srcSRGBEncoded,
                                                              const SkColorSpace* srcColorSpace,
                                                              GrColorType dstColorType,
                                                              const SkColorSpace* dstColorSpace,
                                                              const GrCaps& caps) {
    // This is symmetrical with the write version.
    switch (determine_write_pixels_srgb_conversion(dstColorType, dstColorSpace, srcSRGBEncoded,
                                                   srcColorSpace, caps)) {
        case GrSRGBConversion::kNone:         return GrSRGBConversion::kNone;
        case GrSRGBConversion::kLinearToSRGB: return GrSRGBConversion::kSRGBToLinear;
        case GrSRGBConversion::kSRGBToLinear: return GrSRGBConversion::kLinearToSRGB;
    }
    return GrSRGBConversion::kNone;
}

bool GrContextPriv::writeSurfacePixels(GrSurfaceContext* dst, int left, int top, int width,
                                       int height, GrColorType srcColorType,
                                       SkColorSpace* srcColorSpace, const void* buffer,
                                       size_t rowBytes, uint32_t pixelOpsFlags) {
    bool useLegacyPath = false;
#ifdef SK_LEGACY_GPU_PIXEL_OPS
    useLegacyPath = true;
#endif
    // Newly added color types/configs are only supported by the new code path.
    if (srcColorType == GrColorType::kRGB_888x ||
        dst->asSurfaceProxy()->config() == kRGB_888_GrPixelConfig) {
        useLegacyPath = false;
    }

    if (!useLegacyPath) {
        return this->writeSurfacePixels2(dst, left, top, width, height, srcColorType, srcColorSpace,
                                         buffer, rowBytes, pixelOpsFlags);
    }

    // TODO: Color space conversion

    ASSERT_SINGLE_OWNER_PRIV
    RETURN_FALSE_IF_ABANDONED_PRIV
    SkASSERT(dst);
    ASSERT_OWNED_PROXY_PRIV(dst->asSurfaceProxy());
    GR_CREATE_TRACE_MARKER_CONTEXT("GrContextPriv", "writeSurfacePixels", fContext);

    if (!dst->asSurfaceProxy()->instantiate(this->resourceProvider())) {
        return false;
    }

    GrSurfaceProxy* dstProxy = dst->asSurfaceProxy();
    GrSurface* dstSurface = dstProxy->priv().peekSurface();

    // The src is unpremul but the dst is premul -> premul the src before or as part of the write
    const bool premul = SkToBool(kUnpremul_PixelOpsFlag & pixelOpsFlags);

    if (!valid_pixel_conversion(srcColorType, dstProxy->config(), premul)) {
        return false;
    }
    // There is no way to store alpha values in the dst.
    if (GrColorTypeHasAlpha(srcColorType) && GrPixelConfigIsOpaque(dstProxy->config())) {
        return false;
    }
    // The source has no alpha value and the dst is only alpha
    if (!GrColorTypeHasAlpha(srcColorType) && GrPixelConfigIsAlphaOnly(dstProxy->config())) {
        return false;
    }

    // We need to guarantee round-trip conversion if we are reading and writing 8888 non-sRGB data,
    // without any color spaces attached, and the caller wants us to premul.
    bool useConfigConversionEffect =
            premul && pm_upm_must_round_trip(srcColorType, srcColorSpace) &&
            pm_upm_must_round_trip(dstProxy->config(), dst->colorSpaceInfo().colorSpace());

    // Are we going to try to premul as part of a draw? For the non-legacy case, we always allow
    // this. GrConfigConversionEffect fails on some GPUs, so only allow this if it works perfectly.
    bool premulOnGpu = premul &&
                       (!useConfigConversionEffect || fContext->validPMUPMConversionExists());

    // Trim the params here so that if we wind up making a temporary surface it can be as small as
    // necessary and because GrGpu::getWritePixelsInfo requires it.
    if (!GrSurfacePriv::AdjustWritePixelParams(dstSurface->width(), dstSurface->height(),
                                               GrColorTypeBytesPerPixel(srcColorType), &left, &top,
                                               &width, &height, &buffer, &rowBytes)) {
        return false;
    }

    GrGpu::DrawPreference drawPreference = premulOnGpu ? GrGpu::kCallerPrefersDraw_DrawPreference
                                                       : GrGpu::kNoDraw_DrawPreference;
    GrGpu::WritePixelTempDrawInfo tempDrawInfo;
    GrSRGBConversion srgbConversion = determine_write_pixels_srgb_conversion(
            srcColorType, srcColorSpace, GrPixelConfigIsSRGBEncoded(dstProxy->config()),
            dst->colorSpaceInfo().colorSpace(), *fContext->caps());
    if (!fContext->fGpu->getWritePixelsInfo(dstSurface, dstProxy->origin(), width, height,
                                            srcColorType, srgbConversion, &drawPreference,
                                            &tempDrawInfo)) {
        return false;
    }

    if (!(kDontFlush_PixelOpsFlag & pixelOpsFlags) && dstSurface->surfacePriv().hasPendingIO()) {
        this->flush(nullptr); // MDB TODO: tighten this
    }

    sk_sp<GrTextureProxy> tempProxy;
    if (GrGpu::kNoDraw_DrawPreference != drawPreference) {
        tempProxy = this->proxyProvider()->createProxy(tempDrawInfo.fTempSurfaceDesc,
                                                       kTopLeft_GrSurfaceOrigin,
                                                       SkBackingFit::kApprox, SkBudgeted::kYes);
        if (!tempProxy && GrGpu::kRequireDraw_DrawPreference == drawPreference) {
            return false;
        }
    }

    // temp buffer for doing sw premul conversion, if needed.
    SkAutoSTMalloc<128 * 128, uint32_t> tmpPixels(0);
    // We need to do sw premul if we were unable to create a RT for drawing, or if we can't do the
    // premul on the GPU
    if (premul && (!tempProxy || !premulOnGpu)) {
        size_t tmpRowBytes = 4 * width;
        tmpPixels.reset(width * height);
        if (!sw_convert_to_premul(srcColorType, width, height, rowBytes, buffer, tmpRowBytes,
                                  tmpPixels.get())) {
            return false;
        }
        rowBytes = tmpRowBytes;
        buffer = tmpPixels.get();
    }

    if (tempProxy) {
        auto fp = GrSimpleTextureEffect::Make(tempProxy, SkMatrix::I());
        if (premulOnGpu) {
            fp = fContext->createUPMToPMEffect(std::move(fp), useConfigConversionEffect);
        }
        fp = GrFragmentProcessor::SwizzleOutput(std::move(fp), tempDrawInfo.fSwizzle);
        if (!fp) {
            return false;
        }

        if (!tempProxy->instantiate(this->resourceProvider())) {
            return false;
        }
        GrTexture* texture = tempProxy->priv().peekTexture();

        if (tempProxy->priv().hasPendingIO()) {
            this->flush(tempProxy.get());
        }

        if (!fContext->fGpu->writePixels(texture, tempProxy->origin(), 0, 0, width, height,
                                         tempDrawInfo.fWriteColorType, buffer, rowBytes)) {
            return false;
        }
        tempProxy = nullptr;

        SkMatrix matrix;
        matrix.setTranslate(SkIntToScalar(left), SkIntToScalar(top));
        GrRenderTargetContext* renderTargetContext = dst->asRenderTargetContext();
        if (!renderTargetContext) {
            return false;
        }
        GrPaint paint;
        paint.addColorFragmentProcessor(std::move(fp));
        paint.setPorterDuffXPFactory(SkBlendMode::kSrc);
        paint.setAllowSRGBInputs(dst->colorSpaceInfo().isGammaCorrect() ||
                                 GrPixelConfigIsSRGB(dst->colorSpaceInfo().config()));
        SkRect rect = SkRect::MakeWH(SkIntToScalar(width), SkIntToScalar(height));
        renderTargetContext->drawRect(GrNoClip(), std::move(paint), GrAA::kNo, matrix, rect,
                                        nullptr);

        if (kFlushWrites_PixelOp & pixelOpsFlags) {
            this->flushSurfaceWrites(renderTargetContext->asRenderTargetProxy());
        }
    } else {
        return fContext->fGpu->writePixels(dstSurface, dstProxy->origin(), left, top, width, height,
                                           srcColorType, buffer, rowBytes);
    }
    return true;
}

bool GrContextPriv::readSurfacePixels(GrSurfaceContext* src, int left, int top, int width,
                                      int height, GrColorType dstColorType,
                                      SkColorSpace* dstColorSpace, void* buffer, size_t rowBytes,
                                      uint32_t flags) {
    bool useLegacyPath = false;
#ifdef SK_LEGACY_GPU_PIXEL_OPS
    useLegacyPath = true;
#endif
    // Newly added color types/configs are only supported by the new code path.
    if (dstColorType == GrColorType::kRGB_888x ||
        src->asSurfaceProxy()->config() == kRGB_888_GrPixelConfig) {
        useLegacyPath = false;
    }

    if (!useLegacyPath) {
        return this->readSurfacePixels2(src, left, top, width, height, dstColorType, dstColorSpace,
                                        buffer, rowBytes, flags);
    }

    // TODO: Color space conversion

    ASSERT_SINGLE_OWNER_PRIV
    RETURN_FALSE_IF_ABANDONED_PRIV
    SkASSERT(src);
    ASSERT_OWNED_PROXY_PRIV(src->asSurfaceProxy());
    GR_CREATE_TRACE_MARKER_CONTEXT("GrContextPriv", "readSurfacePixels", fContext);
    SkASSERT(!(flags & kDontFlush_PixelOpsFlag));
    if (flags & kDontFlush_PixelOpsFlag) {
        return false;
    }

    // MDB TODO: delay this instantiation until later in the method
    if (!src->asSurfaceProxy()->instantiate(this->resourceProvider())) {
        return false;
    }

    GrSurfaceProxy* srcProxy = src->asSurfaceProxy();
    GrSurface* srcSurface = srcProxy->priv().peekSurface();

    // The src is premul but the dst is unpremul -> unpremul the src after or as part of the read
    bool unpremul = SkToBool(kUnpremul_PixelOpsFlag & flags);

    if (!valid_pixel_conversion(dstColorType, srcProxy->config(), unpremul)) {
        return false;
    }
    // The source is alpha-only but the dst is not. TODO: Make non-alpha channels in the dst be 0?
    if (GrPixelConfigIsAlphaOnly(srcProxy->config()) && !GrColorTypeIsAlphaOnly(dstColorType)) {
        return false;
    }
    // The source has no alpha, the dst is alpha-only. TODO: set all values in dst to 1?
    if (GrPixelConfigIsOpaque(srcProxy->config()) && GrColorTypeIsAlphaOnly(dstColorType)) {
        return false;
    }
    // Not clear if we should unpremul in this case.
    if (!GrPixelConfigIsOpaque(srcProxy->config()) && !GrColorTypeHasAlpha(dstColorType)) {
        return false;
    }

    // We need to guarantee round-trip conversion if we are reading and writing 8888 non-sRGB data,
    // without any color spaces attached, and the caller wants us to unpremul.
    bool useConfigConversionEffect =
            unpremul &&
            pm_upm_must_round_trip(srcProxy->config(), src->colorSpaceInfo().colorSpace()) &&
            pm_upm_must_round_trip(dstColorType, dstColorSpace);

    // Are we going to try to unpremul as part of a draw? For the non-legacy case, we always allow
    // this. GrConfigConversionEffect fails on some GPUs, so only allow this if it works perfectly.
    bool unpremulOnGpu = unpremul &&
                         (!useConfigConversionEffect || fContext->validPMUPMConversionExists());

    // Adjust the params so that if we wind up using an intermediate surface we've already done
    // all the trimming and the temporary can be the min size required.
    if (!GrSurfacePriv::AdjustReadPixelParams(srcSurface->width(), srcSurface->height(),
                                              GrColorTypeBytesPerPixel(dstColorType), &left, &top,
                                              &width, &height, &buffer, &rowBytes)) {
        return false;
    }

    GrGpu::DrawPreference drawPreference = unpremulOnGpu ? GrGpu::kCallerPrefersDraw_DrawPreference
                                                         : GrGpu::kNoDraw_DrawPreference;
    GrGpu::ReadPixelTempDrawInfo tempDrawInfo;
    GrSRGBConversion srgbConversion = determine_read_pixels_srgb_conversion(
            GrPixelConfigIsSRGBEncoded(srcProxy->config()), src->colorSpaceInfo().colorSpace(),
            dstColorType, dstColorSpace, *fContext->caps());

    if (!fContext->fGpu->getReadPixelsInfo(srcSurface, srcProxy->origin(), width, height, rowBytes,
                                           dstColorType, srgbConversion, &drawPreference,
                                           &tempDrawInfo)) {
        return false;
    }

    if (srcSurface->surfacePriv().hasPendingWrite()) {
        this->flush(nullptr); // MDB TODO: tighten this
    }

    sk_sp<GrSurfaceProxy> proxyToRead = src->asSurfaceProxyRef();
    bool didTempDraw = false;
    if (GrGpu::kNoDraw_DrawPreference != drawPreference) {
        if (SkBackingFit::kExact == tempDrawInfo.fTempSurfaceFit) {
            // We only respect this when the entire src is being read. Otherwise we can trigger too
            // many odd ball texture sizes and trash the cache.
            if (width != srcSurface->width() || height != srcSurface->height()) {
                tempDrawInfo.fTempSurfaceFit= SkBackingFit::kApprox;
            }
        }
        // TODO: Need to decide the semantics of this function for color spaces. Do we support
        // conversion to a passed-in color space? For now, specifying nullptr means that this
        // path will do no conversion, so it will match the behavior of the non-draw path. For
        // now we simply infer an sRGB color space if the config is sRGB in order to avoid an
        // illegal combination.
        sk_sp<SkColorSpace> colorSpace;
        if (GrPixelConfigIsSRGB(tempDrawInfo.fTempSurfaceDesc.fConfig)) {
            colorSpace = SkColorSpace::MakeSRGB();
        }
        sk_sp<GrRenderTargetContext> tempRTC =
                fContext->contextPriv().makeDeferredRenderTargetContext(
                                                          tempDrawInfo.fTempSurfaceFit,
                                                          tempDrawInfo.fTempSurfaceDesc.fWidth,
                                                          tempDrawInfo.fTempSurfaceDesc.fHeight,
                                                          tempDrawInfo.fTempSurfaceDesc.fConfig,
                                                          std::move(colorSpace),
                                                          tempDrawInfo.fTempSurfaceDesc.fSampleCnt,
                                                          GrMipMapped::kNo,
                                                          kTopLeft_GrSurfaceOrigin);
        if (tempRTC) {
            // Adding discard to appease vulkan validation warning about loading uninitialized data
            // on draw
            tempRTC->discard();
            SkMatrix textureMatrix = SkMatrix::MakeTrans(SkIntToScalar(left), SkIntToScalar(top));
            sk_sp<GrTextureProxy> proxy = src->asTextureProxyRef();
            auto fp = GrSimpleTextureEffect::Make(std::move(proxy), textureMatrix);
            if (unpremulOnGpu) {
                fp = fContext->createPMToUPMEffect(std::move(fp), useConfigConversionEffect);
                // We no longer need to do this on CPU after the read back.
                unpremul = false;
            }
            fp = GrFragmentProcessor::SwizzleOutput(std::move(fp), tempDrawInfo.fSwizzle);
            if (!fp) {
                return false;
            }

            GrPaint paint;
            paint.addColorFragmentProcessor(std::move(fp));
            paint.setPorterDuffXPFactory(SkBlendMode::kSrc);
            paint.setAllowSRGBInputs(true);
            SkRect rect = SkRect::MakeWH(SkIntToScalar(width), SkIntToScalar(height));
            tempRTC->drawRect(GrNoClip(), std::move(paint), GrAA::kNo, SkMatrix::I(), rect,
                                nullptr);
            proxyToRead = tempRTC->asTextureProxyRef();
            left = 0;
            top = 0;
            didTempDraw = true;
        }
    }

    if (!proxyToRead) {
        return false;
    }

    if (GrGpu::kRequireDraw_DrawPreference == drawPreference && !didTempDraw) {
        return false;
    }
    GrColorType colorTypeToRead = dstColorType;
    if (didTempDraw) {
        this->flushSurfaceWrites(proxyToRead.get());
        colorTypeToRead = tempDrawInfo.fReadColorType;
    }

    if (!proxyToRead->instantiate(this->resourceProvider())) {
        return false;
    }

    GrSurface* surfaceToRead = proxyToRead->priv().peekSurface();

    if (!fContext->fGpu->readPixels(surfaceToRead, proxyToRead->origin(), left, top, width, height,
                                    colorTypeToRead, buffer, rowBytes)) {
        return false;
    }

    // Perform umpremul conversion if we weren't able to perform it as a draw.
    if (unpremul) {
        SkColorType colorType = GrColorTypeToSkColorType(dstColorType);
        if (kUnknown_SkColorType == colorType || 4 != SkColorTypeBytesPerPixel(colorType)) {
            return false;
        }

        for (int y = 0; y < height; y++) {
            SkUnpremultiplyRow<false>((uint32_t*) buffer, (const uint32_t*) buffer, width);
            buffer = SkTAddOffset<void>(buffer, rowBytes);
        }
    }
    return true;
}

bool GrContextPriv::writeSurfacePixels2(GrSurfaceContext* dst, int left, int top, int width,
                                        int height, GrColorType srcColorType,
                                        SkColorSpace* srcColorSpace, const void* buffer,
                                        size_t rowBytes, uint32_t pixelOpsFlags) {
    ASSERT_SINGLE_OWNER_PRIV
    RETURN_FALSE_IF_ABANDONED_PRIV
    SkASSERT(dst);
    SkASSERT(buffer);
    ASSERT_OWNED_PROXY_PRIV(dst->asSurfaceProxy());
    GR_CREATE_TRACE_MARKER_CONTEXT("GrContextPriv", "writeSurfacePixels2", fContext);

    if (GrColorType::kUnknown == srcColorType) {
        return false;
    }

    if (!dst->asSurfaceProxy()->instantiate(this->resourceProvider())) {
        return false;
    }

    GrSurfaceProxy* dstProxy = dst->asSurfaceProxy();
    GrSurface* dstSurface = dstProxy->priv().peekSurface();

    if (!GrSurfacePriv::AdjustWritePixelParams(dstSurface->width(), dstSurface->height(),
                                               GrColorTypeBytesPerPixel(srcColorType), &left, &top,
                                               &width, &height, &buffer, &rowBytes)) {
        return false;
    }

    // TODO: Make GrSurfaceContext know its alpha type and pass src buffer's alpha type.
    bool premul = SkToBool(kUnpremul_PixelOpsFlag & pixelOpsFlags);

    // For canvas2D putImageData performance we have a special code path for unpremul RGBA_8888 srcs
    // that are premultiplied on the GPU. This is kept as narrow as possible for now.
    bool canvas2DFastPath = premul &&
                            !dst->colorSpaceInfo().isGammaCorrect() &&
                            GrColorType::kRGBA_8888 == srcColorType &&
                            SkToBool(dst->asRenderTargetContext()) &&
                            (dstProxy->config() == kRGBA_8888_GrPixelConfig ||
                             dstProxy->config() == kBGRA_8888_GrPixelConfig) &&
                            !(pixelOpsFlags & kDontFlush_PixelOpsFlag) &&
                            fContext->caps()->isConfigTexturable(kRGBA_8888_GrPixelConfig) &&
                            fContext->validPMUPMConversionExists();

    if (!fContext->caps()->surfaceSupportsWritePixels(dstSurface) || canvas2DFastPath) {
        // We don't expect callers that are skipping flushes to require an intermediate draw.
        SkASSERT(!(pixelOpsFlags & kDontFlush_PixelOpsFlag));
        if (pixelOpsFlags & kDontFlush_PixelOpsFlag) {
            return false;
        }

        GrSurfaceDesc desc;
        desc.fConfig = canvas2DFastPath ? kRGBA_8888_GrPixelConfig : dstProxy->config();
        desc.fWidth = width;
        desc.fHeight = height;
        desc.fSampleCnt = 1;
        auto tempProxy = this->proxyProvider()->createProxy(
                desc, kTopLeft_GrSurfaceOrigin, SkBackingFit::kApprox, SkBudgeted::kYes);
        if (!tempProxy) {
            return false;
        }
        auto tempCtx = this->drawingManager()->makeTextureContext(
                tempProxy, dst->colorSpaceInfo().refColorSpace());
        if (!tempCtx) {
            return false;
        }
        uint32_t flags = canvas2DFastPath ? 0 : pixelOpsFlags;
        if (!this->writeSurfacePixels2(tempCtx.get(), 0, 0, width, height, srcColorType,
                                       srcColorSpace, buffer, rowBytes, flags)) {
            return false;
        }
        if (canvas2DFastPath) {
            GrPaint paint;
            paint.setPorterDuffXPFactory(SkBlendMode::kSrc);
            paint.addColorFragmentProcessor(fContext->createUPMToPMEffect(
                    GrSimpleTextureEffect::Make(std::move(tempProxy), SkMatrix::I()), true));
            dst->asRenderTargetContext()->fillRectToRect(
                    GrNoClip(), std::move(paint), GrAA::kNo, SkMatrix::I(),
                    SkRect::MakeXYWH(left, top, width, height), SkRect::MakeWH(width, height));
            return true;
        } else {
            return dst->copy(tempProxy.get(), SkIRect::MakeWH(width, height), {left, top});
        }
    }

    bool convert = premul;

    if (!valid_pixel_conversion(srcColorType, dstProxy->config(), premul)) {
        return false;
    }

    GrColorType allowedColorType =
            fContext->caps()->supportedWritePixelsColorType(dstProxy->config(), srcColorType);
    convert = convert || (srcColorType != allowedColorType);

    if (!dst->colorSpaceInfo().colorSpace()) {
        // "Legacy" mode - no color space conversions.
        srcColorSpace = nullptr;
    }
    convert = convert || !SkColorSpace::Equals(srcColorSpace, dst->colorSpaceInfo().colorSpace());

    std::unique_ptr<char[]> tempBuffer;
    if (convert) {
        auto srcSkColorType = GrColorTypeToSkColorType(srcColorType);
        auto dstSkColorType = GrColorTypeToSkColorType(allowedColorType);
        if (kUnknown_SkColorType == srcSkColorType || kUnknown_SkColorType == dstSkColorType) {
            return false;
        }
        auto srcAlphaType = premul ? kUnpremul_SkAlphaType : kPremul_SkAlphaType;
        SkPixmap src(SkImageInfo::Make(width, height, srcSkColorType, srcAlphaType,
                                       sk_ref_sp(srcColorSpace)),
                     buffer, rowBytes);
        auto tempSrcII = SkImageInfo::Make(width, height, dstSkColorType, kPremul_SkAlphaType,
                                           dst->colorSpaceInfo().refColorSpace());
        auto size = tempSrcII.computeMinByteSize();
        if (!size) {
            return false;
        }
        tempBuffer.reset(new char[size]);
        SkPixmap tempSrc(tempSrcII, tempBuffer.get(), tempSrcII.minRowBytes());
        if (!src.readPixels(tempSrc)) {
            return false;
        }
        srcColorType = allowedColorType;
        buffer = tempSrc.addr();
        rowBytes = tempSrc.rowBytes();
        if (dstProxy->origin() == kBottomLeft_GrSurfaceOrigin) {
            std::unique_ptr<char[]> row(new char[rowBytes]);
            for (int y = 0; y < height / 2; ++y) {
                memcpy(row.get(), tempSrc.addr(0, y), rowBytes);
                memcpy(tempSrc.writable_addr(0, y), tempSrc.addr(0, height - 1 - y), rowBytes);
                memcpy(tempSrc.writable_addr(0, height - 1 - y), row.get(), rowBytes);
            }
            top = dstSurface->height() - top - height;
        }
    } else if (dstProxy->origin() == kBottomLeft_GrSurfaceOrigin) {
        size_t trimRowBytes = GrColorTypeBytesPerPixel(srcColorType) * width;
        tempBuffer.reset(new char[trimRowBytes * height]);
        char* dst = reinterpret_cast<char*>(tempBuffer.get()) + trimRowBytes * (height - 1);
        const char* src = reinterpret_cast<const char*>(buffer);
        for (int i = 0; i < height; ++i, src += rowBytes, dst -= trimRowBytes) {
            memcpy(dst, src, trimRowBytes);
        }
        buffer = tempBuffer.get();
        rowBytes = trimRowBytes;
        top = dstSurface->height() - top - height;
    }

    if (!(kDontFlush_PixelOpsFlag & pixelOpsFlags) && dstSurface->surfacePriv().hasPendingIO()) {
        this->flush(nullptr);  // MDB TODO: tighten this
    }

    return this->getGpu()->writePixels(dstSurface, left, top, width, height, srcColorType, buffer,
                                       rowBytes);
}

bool GrContextPriv::readSurfacePixels2(GrSurfaceContext* src, int left, int top, int width,
                                       int height, GrColorType dstColorType,
                                       SkColorSpace* dstColorSpace, void* buffer, size_t rowBytes,
                                       uint32_t pixelOpsFlags) {
    ASSERT_SINGLE_OWNER_PRIV
    RETURN_FALSE_IF_ABANDONED_PRIV
    SkASSERT(src);
    SkASSERT(buffer);
    ASSERT_OWNED_PROXY_PRIV(src->asSurfaceProxy());
    GR_CREATE_TRACE_MARKER_CONTEXT("GrContextPriv", "readSurfacePixels2", fContext);

    SkASSERT(!(pixelOpsFlags & kDontFlush_PixelOpsFlag));
    if (pixelOpsFlags & kDontFlush_PixelOpsFlag) {
        return false;
    }

    // MDB TODO: delay this instantiation until later in the method
    if (!src->asSurfaceProxy()->instantiate(this->resourceProvider())) {
        return false;
    }

    GrSurfaceProxy* srcProxy = src->asSurfaceProxy();
    GrSurface* srcSurface = srcProxy->priv().peekSurface();

    if (!GrSurfacePriv::AdjustReadPixelParams(srcSurface->width(), srcSurface->height(),
                                              GrColorTypeBytesPerPixel(dstColorType), &left, &top,
                                              &width, &height, &buffer, &rowBytes)) {
        return false;
    }

    // TODO: Make GrSurfaceContext know its alpha type and pass dst buffer's alpha type.
    bool unpremul = SkToBool(kUnpremul_PixelOpsFlag & pixelOpsFlags);

    if (!valid_pixel_conversion(dstColorType, srcProxy->config(), unpremul)) {
        return false;
    }

    // This is the getImageData equivalent to the canvas2D putImageData fast path. We probably don't
    // care so much about getImageData performance. However, in order to ensure putImageData/
    // getImageData in "legacy" mode are round-trippable we use the GPU to do the complementary
    // unpremul step to writeSurfacePixels2's premul step (which is determined empirically in
    // fContext->vaildaPMUPMConversionExists()).
    bool canvas2DFastPath = unpremul &&
                            !src->colorSpaceInfo().isGammaCorrect() &&
                            GrColorType::kRGBA_8888 == dstColorType &&
                            SkToBool(srcProxy->asTextureProxy()) &&
                            (srcProxy->config() == kRGBA_8888_GrPixelConfig ||
                             srcProxy->config() == kBGRA_8888_GrPixelConfig) &&
                            fContext->caps()->isConfigRenderable(kRGBA_8888_GrPixelConfig) &&
                            fContext->validPMUPMConversionExists();

    if (!fContext->caps()->surfaceSupportsReadPixels(srcSurface) || canvas2DFastPath) {
        GrSurfaceDesc desc;
        desc.fFlags = canvas2DFastPath ? kRenderTarget_GrSurfaceFlag : kNone_GrSurfaceFlags;
        desc.fConfig = canvas2DFastPath ? kRGBA_8888_GrPixelConfig : srcProxy->config();
        desc.fWidth = width;
        desc.fHeight = height;
        desc.fSampleCnt = 1;
        auto tempProxy = this->proxyProvider()->createProxy(
                desc, kTopLeft_GrSurfaceOrigin, SkBackingFit::kApprox, SkBudgeted::kYes);
        if (!tempProxy) {
            return false;
        }
        sk_sp<GrSurfaceContext> tempCtx;
        if (canvas2DFastPath) {
            tempCtx = this->drawingManager()->makeRenderTargetContext(std::move(tempProxy), nullptr,
                                                                      nullptr);
        } else {
            tempCtx = this->drawingManager()->makeTextureContext(
                    std::move(tempProxy), src->colorSpaceInfo().refColorSpace());
        }
        if (!tempCtx) {
            return false;
        }
        if (canvas2DFastPath) {
            GrPaint paint;
            paint.setPorterDuffXPFactory(SkBlendMode::kSrc);
            paint.addColorFragmentProcessor(fContext->createPMToUPMEffect(
                    GrSimpleTextureEffect::Make(sk_ref_sp(srcProxy->asTextureProxy()),
                                                SkMatrix::I()),
                    true));
            tempCtx->asRenderTargetContext()->fillRectToRect(
                    GrNoClip(), std::move(paint), GrAA::kNo, SkMatrix::I(),
                    SkRect::MakeWH(width, height), SkRect::MakeXYWH(left, top, width, height));
        } else if (!tempCtx->copy(srcProxy, SkIRect::MakeXYWH(left, top, width, height), {0, 0})) {
            return false;
        }
        uint32_t flags = canvas2DFastPath ? 0 : pixelOpsFlags;
        return this->readSurfacePixels2(tempCtx.get(), 0, 0, width, height, dstColorType,
                                        dstColorSpace, buffer, rowBytes, flags);
    }

    bool convert = unpremul;

    bool flip = srcProxy->origin() == kBottomLeft_GrSurfaceOrigin;
    if (flip) {
        top = srcSurface->height() - top - height;
    }

    GrColorType allowedColorType =
            fContext->caps()->supportedReadPixelsColorType(srcProxy->config(), dstColorType);
    convert = convert || (dstColorType != allowedColorType);

    if (!src->colorSpaceInfo().colorSpace()) {
        // "Legacy" mode - no color space conversions.
        dstColorSpace = nullptr;
    }
    convert = convert || !SkColorSpace::Equals(dstColorSpace, src->colorSpaceInfo().colorSpace());

    SkAutoPixmapStorage tempPixmap;
    SkPixmap finalPixmap;
    if (convert) {
        SkColorType srcSkColorType = GrColorTypeToSkColorType(allowedColorType);
        SkColorType dstSkColorType = GrColorTypeToSkColorType(dstColorType);
        if (kUnknown_SkColorType == srcSkColorType || kUnknown_SkColorType == dstSkColorType) {
            return false;
        }
        auto tempAT = SkColorTypeIsAlwaysOpaque(srcSkColorType) ? kOpaque_SkAlphaType
                                                                : kPremul_SkAlphaType;
        auto tempII = SkImageInfo::Make(width, height, srcSkColorType, tempAT,
                                        src->colorSpaceInfo().refColorSpace());
        SkASSERT(!unpremul || !SkColorTypeIsAlwaysOpaque(dstSkColorType));
        auto finalAT = SkColorTypeIsAlwaysOpaque(srcSkColorType)
                               ? kOpaque_SkAlphaType
                               : unpremul ? kUnpremul_SkAlphaType : kPremul_SkAlphaType;
        auto finalII =
                SkImageInfo::Make(width, height, dstSkColorType, finalAT, sk_ref_sp(dstColorSpace));
        if (!SkImageInfoValidConversion(finalII, tempII)) {
            return false;
        }
        tempPixmap.alloc(tempII);
        finalPixmap.reset(finalII, buffer, rowBytes);
        buffer = tempPixmap.writable_addr();
        rowBytes = tempPixmap.rowBytes();
    }

    if (srcSurface->surfacePriv().hasPendingWrite()) {
        this->flush(nullptr);  // MDB TODO: tighten this
    }

    if (!fContext->fGpu->readPixels(srcSurface, left, top, width, height, allowedColorType, buffer,
                                    rowBytes)) {
        return false;
    }

    if (flip) {
        size_t trimRowBytes = GrColorTypeBytesPerPixel(allowedColorType) * width;
        std::unique_ptr<char[]> row(new char[trimRowBytes]);
        char* upper = reinterpret_cast<char*>(buffer);
        char* lower = reinterpret_cast<char*>(buffer) + (height - 1) * rowBytes;
        for (int y = 0; y < height / 2; ++y, upper += rowBytes, lower -= rowBytes) {
            memcpy(row.get(), upper, trimRowBytes);
            memcpy(upper, lower, trimRowBytes);
            memcpy(lower, row.get(), trimRowBytes);
        }
    }
    if (convert) {
        if (!tempPixmap.readPixels(finalPixmap)) {
            return false;
        }
    }
    return true;
}

void GrContextPriv::prepareSurfaceForExternalIO(GrSurfaceProxy* proxy) {
    ASSERT_SINGLE_OWNER_PRIV
    RETURN_IF_ABANDONED_PRIV
    SkASSERT(proxy);
    ASSERT_OWNED_PROXY_PRIV(proxy);
    fContext->fDrawingManager->prepareSurfaceForExternalIO(proxy, 0, nullptr);
}

void GrContextPriv::flushSurfaceWrites(GrSurfaceProxy* proxy) {
    ASSERT_SINGLE_OWNER_PRIV
    RETURN_IF_ABANDONED_PRIV
    SkASSERT(proxy);
    ASSERT_OWNED_PROXY_PRIV(proxy);
    if (proxy->priv().hasPendingWrite()) {
        this->flush(proxy);
    }
}

void GrContextPriv::flushSurfaceIO(GrSurfaceProxy* proxy) {
    ASSERT_SINGLE_OWNER_PRIV
    RETURN_IF_ABANDONED_PRIV
    SkASSERT(proxy);
    ASSERT_OWNED_PROXY_PRIV(proxy);
    if (proxy->priv().hasPendingIO()) {
        this->flush(proxy);
    }
}

////////////////////////////////////////////////////////////////////////////////

sk_sp<GrSurfaceContext> GrContextPriv::makeWrappedSurfaceContext(sk_sp<GrSurfaceProxy> proxy,
                                                                 sk_sp<SkColorSpace> colorSpace,
                                                                 const SkSurfaceProps* props) {
    ASSERT_SINGLE_OWNER_PRIV

    // sRGB pixel configs may only be used with near-sRGB gamma color spaces.
    if (GrPixelConfigIsSRGB(proxy->config())) {
        if (!colorSpace || !colorSpace->gammaCloseToSRGB()) {
            return nullptr;
        }
    }
    if (proxy->asRenderTargetProxy()) {
        return this->drawingManager()->makeRenderTargetContext(std::move(proxy),
                                                               std::move(colorSpace), props);
    } else {
        SkASSERT(proxy->asTextureProxy());
        SkASSERT(!props);
        return this->drawingManager()->makeTextureContext(std::move(proxy), std::move(colorSpace));
    }
}

sk_sp<GrSurfaceContext> GrContextPriv::makeDeferredSurfaceContext(const GrSurfaceDesc& dstDesc,
                                                                  GrSurfaceOrigin origin,
                                                                  GrMipMapped mipMapped,
                                                                  SkBackingFit fit,
                                                                  SkBudgeted isDstBudgeted,
                                                                  sk_sp<SkColorSpace> colorSpace,
                                                                  const SkSurfaceProps* props) {
    sk_sp<GrTextureProxy> proxy;
    if (GrMipMapped::kNo == mipMapped) {
        proxy = this->proxyProvider()->createProxy(dstDesc, origin, fit, isDstBudgeted);
    } else {
        SkASSERT(SkBackingFit::kExact == fit);
        proxy = this->proxyProvider()->createMipMapProxy(dstDesc, origin, isDstBudgeted);
    }
    if (!proxy) {
        return nullptr;
    }

    sk_sp<GrSurfaceContext> sContext = this->makeWrappedSurfaceContext(std::move(proxy),
                                                                       std::move(colorSpace),
                                                                       props);
    if (sContext && sContext->asRenderTargetContext()) {
        sContext->asRenderTargetContext()->discard();
    }

    return sContext;
}

sk_sp<GrTextureContext> GrContextPriv::makeBackendTextureContext(const GrBackendTexture& tex,
                                                                 GrSurfaceOrigin origin,
                                                                 sk_sp<SkColorSpace> colorSpace) {
    ASSERT_SINGLE_OWNER_PRIV

    sk_sp<GrSurfaceProxy> proxy = this->proxyProvider()->wrapBackendTexture(tex, origin);
    if (!proxy) {
        return nullptr;
    }

    return this->drawingManager()->makeTextureContext(std::move(proxy), std::move(colorSpace));
}

sk_sp<GrRenderTargetContext> GrContextPriv::makeBackendTextureRenderTargetContext(
                                                                   const GrBackendTexture& tex,
                                                                   GrSurfaceOrigin origin,
                                                                   int sampleCnt,
                                                                   sk_sp<SkColorSpace> colorSpace,
                                                                   const SkSurfaceProps* props) {
    ASSERT_SINGLE_OWNER_PRIV
    SkASSERT(sampleCnt > 0);

    sk_sp<GrTextureProxy> proxy(
            this->proxyProvider()->wrapRenderableBackendTexture(tex, origin, sampleCnt));
    if (!proxy) {
        return nullptr;
    }

    return this->drawingManager()->makeRenderTargetContext(std::move(proxy),
                                                           std::move(colorSpace), props);
}

sk_sp<GrRenderTargetContext> GrContextPriv::makeBackendRenderTargetRenderTargetContext(
                                                const GrBackendRenderTarget& backendRT,
                                                GrSurfaceOrigin origin,
                                                sk_sp<SkColorSpace> colorSpace,
                                                const SkSurfaceProps* surfaceProps) {
    ASSERT_SINGLE_OWNER_PRIV

    sk_sp<GrSurfaceProxy> proxy = this->proxyProvider()->wrapBackendRenderTarget(backendRT, origin);
    if (!proxy) {
        return nullptr;
    }

    return this->drawingManager()->makeRenderTargetContext(std::move(proxy),
                                                           std::move(colorSpace),
                                                           surfaceProps);
}

sk_sp<GrRenderTargetContext> GrContextPriv::makeBackendTextureAsRenderTargetRenderTargetContext(
                                                     const GrBackendTexture& tex,
                                                     GrSurfaceOrigin origin,
                                                     int sampleCnt,
                                                     sk_sp<SkColorSpace> colorSpace,
                                                     const SkSurfaceProps* props) {
    ASSERT_SINGLE_OWNER_PRIV
    SkASSERT(sampleCnt > 0);
    sk_sp<GrSurfaceProxy> proxy(
            this->proxyProvider()->wrapBackendTextureAsRenderTarget(tex, origin, sampleCnt));
    if (!proxy) {
        return nullptr;
    }

    return this->drawingManager()->makeRenderTargetContext(std::move(proxy),
                                                           std::move(colorSpace),
                                                           props);
}

void GrContextPriv::addOnFlushCallbackObject(GrOnFlushCallbackObject* onFlushCBObject) {
    fContext->fDrawingManager->addOnFlushCallbackObject(onFlushCBObject);
}

void GrContextPriv::moveOpListsToDDL(SkDeferredDisplayList* ddl) {
    fContext->fDrawingManager->moveOpListsToDDL(ddl);
}

void GrContextPriv::copyOpListsFromDDL(const SkDeferredDisplayList* ddl,
                                       GrRenderTargetProxy* newDest) {
    fContext->fDrawingManager->copyOpListsFromDDL(ddl, newDest);
}

static inline GrPixelConfig GrPixelConfigFallback(GrPixelConfig config) {
    switch (config) {
        case kAlpha_8_GrPixelConfig:
        case kRGB_565_GrPixelConfig:
        case kRGBA_4444_GrPixelConfig:
        case kBGRA_8888_GrPixelConfig:
        case kRGBA_1010102_GrPixelConfig:
            return kRGBA_8888_GrPixelConfig;
        case kSBGRA_8888_GrPixelConfig:
            return kSRGBA_8888_GrPixelConfig;
        case kAlpha_half_GrPixelConfig:
            return kRGBA_half_GrPixelConfig;
        default:
            return kUnknown_GrPixelConfig;
    }
}

sk_sp<GrRenderTargetContext> GrContextPriv::makeDeferredRenderTargetContextWithFallback(
                                                                 SkBackingFit fit,
                                                                 int width, int height,
                                                                 GrPixelConfig config,
                                                                 sk_sp<SkColorSpace> colorSpace,
                                                                 int sampleCnt,
                                                                 GrMipMapped mipMapped,
                                                                 GrSurfaceOrigin origin,
                                                                 const SkSurfaceProps* surfaceProps,
                                                                 SkBudgeted budgeted) {
    SkASSERT(sampleCnt > 0);
    if (0 == fContext->caps()->getRenderTargetSampleCount(sampleCnt, config)) {
        config = GrPixelConfigFallback(config);
    }

    return this->makeDeferredRenderTargetContext(fit, width, height, config, std::move(colorSpace),
                                                 sampleCnt, mipMapped, origin, surfaceProps,
                                                 budgeted);
}

sk_sp<GrRenderTargetContext> GrContextPriv::makeDeferredRenderTargetContext(
                                                        SkBackingFit fit,
                                                        int width, int height,
                                                        GrPixelConfig config,
                                                        sk_sp<SkColorSpace> colorSpace,
                                                        int sampleCnt,
                                                        GrMipMapped mipMapped,
                                                        GrSurfaceOrigin origin,
                                                        const SkSurfaceProps* surfaceProps,
                                                        SkBudgeted budgeted) {
    SkASSERT(sampleCnt > 0);
    if (this->abandoned()) {
        return nullptr;
    }

    GrSurfaceDesc desc;
    desc.fFlags = kRenderTarget_GrSurfaceFlag;
    desc.fWidth = width;
    desc.fHeight = height;
    desc.fConfig = config;
    desc.fSampleCnt = sampleCnt;

    sk_sp<GrTextureProxy> rtp;
    if (GrMipMapped::kNo == mipMapped) {
        rtp = fContext->fProxyProvider->createProxy(desc, origin, fit, budgeted);
    } else {
        rtp = fContext->fProxyProvider->createMipMapProxy(desc, origin, budgeted);
    }
    if (!rtp) {
        return nullptr;
    }

    sk_sp<GrRenderTargetContext> renderTargetContext(
        fContext->fDrawingManager->makeRenderTargetContext(std::move(rtp),
                                                           std::move(colorSpace),
                                                           surfaceProps));
    if (!renderTargetContext) {
        return nullptr;
    }

    renderTargetContext->discard();

    return renderTargetContext;
}

bool GrContextPriv::abandoned() const {
    ASSERT_SINGLE_OWNER_PRIV
    return fContext->fDrawingManager->wasAbandoned();
}

std::unique_ptr<GrFragmentProcessor> GrContext::createPMToUPMEffect(
        std::unique_ptr<GrFragmentProcessor> fp, bool useConfigConversionEffect) {
    ASSERT_SINGLE_OWNER
    // We have specialized effects that guarantee round-trip conversion for some formats
    if (useConfigConversionEffect) {
        // We should have already called this->validPMUPMConversionExists() in this case
        SkASSERT(fDidTestPMConversions);
        // ...and it should have succeeded
        SkASSERT(this->validPMUPMConversionExists());

        return GrConfigConversionEffect::Make(std::move(fp), PMConversion::kToUnpremul);
    } else {
        // For everything else (sRGB, half-float, etc...), it doesn't make sense to try and
        // explicitly round the results. Just do the obvious, naive thing in the shader.
        return GrFragmentProcessor::UnpremulOutput(std::move(fp));
    }
}

std::unique_ptr<GrFragmentProcessor> GrContext::createUPMToPMEffect(
        std::unique_ptr<GrFragmentProcessor> fp, bool useConfigConversionEffect) {
    ASSERT_SINGLE_OWNER
    // We have specialized effects that guarantee round-trip conversion for these formats
    if (useConfigConversionEffect) {
        // We should have already called this->validPMUPMConversionExists() in this case
        SkASSERT(fDidTestPMConversions);
        // ...and it should have succeeded
        SkASSERT(this->validPMUPMConversionExists());

        return GrConfigConversionEffect::Make(std::move(fp), PMConversion::kToPremul);
    } else {
        // For everything else (sRGB, half-float, etc...), it doesn't make sense to try and
        // explicitly round the results. Just do the obvious, naive thing in the shader.
        return GrFragmentProcessor::PremulOutput(std::move(fp));
    }
}

bool GrContext::validPMUPMConversionExists() {
    ASSERT_SINGLE_OWNER
    if (!fDidTestPMConversions) {
        fPMUPMConversionsRoundTrip = GrConfigConversionEffect::TestForPreservingPMConversions(this);
        fDidTestPMConversions = true;
    }

    // The PM<->UPM tests fail or succeed together so we only need to check one.
    return fPMUPMConversionsRoundTrip;
}

//////////////////////////////////////////////////////////////////////////////

// DDL TODO: remove 'maxResources'
void GrContext::getResourceCacheLimits(int* maxResources, size_t* maxResourceBytes) const {
    ASSERT_SINGLE_OWNER
    if (maxResources) {
        *maxResources = fResourceCache->getMaxResourceCount();
    }
    if (maxResourceBytes) {
        *maxResourceBytes = fResourceCache->getMaxResourceBytes();
    }
}

void GrContext::setResourceCacheLimits(int maxResources, size_t maxResourceBytes) {
    ASSERT_SINGLE_OWNER
    fResourceCache->setLimits(maxResources, maxResourceBytes);
}

//////////////////////////////////////////////////////////////////////////////
void GrContext::dumpMemoryStatistics(SkTraceMemoryDump* traceMemoryDump) const {
    ASSERT_SINGLE_OWNER
    fResourceCache->dumpMemoryStatistics(traceMemoryDump);
}

//////////////////////////////////////////////////////////////////////////////

SkString GrContextPriv::dump() const {
    SkDynamicMemoryWStream stream;
    SkJSONWriter writer(&stream, SkJSONWriter::Mode::kPretty);
    writer.beginObject();

    static const char* kBackendStr[] = {
        "Metal",
        "OpenGL",
        "Vulkan",
        "Mock",
    };
    GR_STATIC_ASSERT(0 == kMetal_GrBackend);
    GR_STATIC_ASSERT(1 == kOpenGL_GrBackend);
    GR_STATIC_ASSERT(2 == kVulkan_GrBackend);
    GR_STATIC_ASSERT(3 == kMock_GrBackend);
    writer.appendString("backend", kBackendStr[fContext->fBackend]);

    writer.appendName("caps");
    fContext->fCaps->dumpJSON(&writer);

    writer.appendName("gpu");
    fContext->fGpu->dumpJSON(&writer);

    // Flush JSON to the memory stream
    writer.endObject();
    writer.flush();

    // Null terminate the JSON data in the memory stream
    stream.write8(0);

    // Allocate a string big enough to hold all the data, then copy out of the stream
    SkString result(stream.bytesWritten());
    stream.copyToAndReset(result.writable_str());
    return result;
}