src/dawn/wire/client/LimitsAndFeatures.cpp

// Copyright 2021 The Dawn & Tint Authors
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#include "dawn/wire/client/LimitsAndFeatures.h"

#include "dawn/common/Assert.h"
#include "dawn/wire/SupportedFeatures.h"

namespace dawn::wire::client {

LimitsAndFeatures::LimitsAndFeatures() = default;

LimitsAndFeatures::~LimitsAndFeatures() = default;

bool LimitsAndFeatures::GetLimits(WGPUSupportedLimits* limits) const {
    DAWN_ASSERT(limits != nullptr);
    auto* originalNextInChain = limits->nextInChain;
    *limits = mLimits;
    limits->nextInChain = originalNextInChain;
    // Handle other requiring limits that chained after WGPUSupportedLimits
    for (auto* chain = limits->nextInChain; chain; chain = chain->next) {
        // Store the WGPUChainedStructOut to restore the chain after assignment.
        WGPUChainedStructOut originalChainedStructOut = *chain;
        switch (chain->sType) {
            case (WGPUSType_DawnExperimentalSubgroupLimits): {
                auto* experimentalSubgroupLimits =
                    reinterpret_cast<WGPUDawnExperimentalSubgroupLimits*>(chain);
                // This assignment break the next field of WGPUChainedStructOut head.
                *experimentalSubgroupLimits = mExperimentalSubgroupLimits;
                break;
            }
            default:
                // Fail if unknown sType found.
                return false;
        }
        // Restore the chain.
        *chain = originalChainedStructOut;
    }
    return true;
}

bool LimitsAndFeatures::HasFeature(WGPUFeatureName feature) const {
    return mFeatures.contains(feature);
}

size_t LimitsAndFeatures::EnumerateFeatures(WGPUFeatureName* features) const {
    if (features != nullptr) {
        for (WGPUFeatureName f : mFeatures) {
            *features = f;
            ++features;
        }
    }
    return mFeatures.size();
}

void LimitsAndFeatures::SetLimits(const WGPUSupportedLimits* limits) {
    DAWN_ASSERT(limits != nullptr);
    mLimits = *limits;
    mLimits.nextInChain = nullptr;
    // Handle other limits that chained after WGPUSupportedLimits
    for (auto* chain = limits->nextInChain; chain; chain = chain->next) {
        switch (chain->sType) {
            case (WGPUSType_DawnExperimentalSubgroupLimits): {
                auto* experimentalSubgroupLimits =
                    reinterpret_cast<WGPUDawnExperimentalSubgroupLimits*>(chain);
                mExperimentalSubgroupLimits = *experimentalSubgroupLimits;
                mExperimentalSubgroupLimits.chain.next = nullptr;
                break;
            }
            default:
                DAWN_UNREACHABLE();
        }
    }
}

void LimitsAndFeatures::SetFeatures(const WGPUFeatureName* features, uint32_t featuresCount) {
    DAWN_ASSERT(features != nullptr || featuresCount == 0);
    for (uint32_t i = 0; i < featuresCount; ++i) {
        // Filter out features that the server supports, but the client does not.
        // (Could be different versions)
        if (!IsFeatureSupported(features[i])) {
            continue;
        }
        mFeatures.insert(features[i]);
    }
}

}  // namespace dawn::wire::client