generator/templates/dawn_native/ChainUtils.h

// Copyright 2021 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.

#ifndef DAWNNATIVE_CHAIN_UTILS_H_
#define DAWNNATIVE_CHAIN_UTILS_H_

#include "dawn_native/dawn_platform.h"
#include "dawn_native/Error.h"

namespace dawn_native {
    {% for value in types["s type"].values %}
        {% if value.valid %}
            void FindInChain(const ChainedStruct* chain, const {{as_cppEnum(value.name)}}** out);
        {% endif %}
    {% endfor %}

    // Verifies that |chain| only contains ChainedStructs of types enumerated in
    // |oneOfConstraints| and contains no duplicate sTypes. Each vector in
    // |oneOfConstraints| defines a set of sTypes that cannot coexist in the same chain.
    // For example:
    //   ValidateSTypes(chain, { { ShaderModuleSPIRVDescriptor, ShaderModuleWGSLDescriptor } }))
    //   ValidateSTypes(chain, { { Extension1 }, { Extension2 } })
    MaybeError ValidateSTypes(const ChainedStruct* chain,
                              std::vector<std::vector<wgpu::SType>> oneOfConstraints);

    template <typename T>
    MaybeError ValidateSingleSTypeInner(const ChainedStruct* chain, T sType) {
        if (chain->sType != sType) {
            return DAWN_VALIDATION_ERROR("Unsupported sType");
        }
        return {};
    }

    template <typename T, typename... Args>
    MaybeError ValidateSingleSTypeInner(const ChainedStruct* chain, T sType, Args... sTypes) {
        if (chain->sType == sType) {
            return {};
        }
        return ValidateSingleSTypeInner(chain, sTypes...);
    }

    // Verifies that |chain| contains a single ChainedStruct of type |sType| or no ChainedStructs
    // at all.
    template <typename T>
    MaybeError ValidateSingleSType(const ChainedStruct* chain, T sType) {
        if (chain == nullptr) {
            return {};
        }
        if (chain->nextInChain != nullptr) {
            return DAWN_VALIDATION_ERROR("Chain can only contain a single chained struct");
        }
        return ValidateSingleSTypeInner(chain, sType);
    }

    // Verifies that |chain| contains a single ChainedStruct with a type enumerated in the
    // parameter pack or no ChainedStructs at all.
    template <typename T, typename... Args>
    MaybeError ValidateSingleSType(const ChainedStruct* chain, T sType, Args... sTypes) {
        if (chain == nullptr) {
            return {};
        }
        if (chain->nextInChain != nullptr) {
            return DAWN_VALIDATION_ERROR("Chain can only contain a single chained struct");
        }
        return ValidateSingleSTypeInner(chain, sType, sTypes...);
    }

}  // namespace dawn_native

#endif  // DAWNNATIVE_CHAIN_UTILS_H_