// Copyright 2018 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_PASSRESOURCEUSAGE_H
#define DAWNNATIVE_PASSRESOURCEUSAGE_H

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

#include <set>
#include <vector>

namespace dawn_native {

    // This file declares various "ResourceUsage" structures. They are produced by the frontend
    // while recording commands to be used for later validation and also some operations in the
    // backends. The are produced by the "Encoder" objects that finalize them on "EndPass" or
    // "Finish". Internally the "Encoder" may use the "StateTracker" to create them.

    class BufferBase;
    class QuerySetBase;
    class TextureBase;

    // The texture usage inside passes must be tracked per-subresource.
    using TextureSubresourceUsage = SubresourceStorage<wgpu::TextureUsage>;

    // Which resources are used by a synchronization scope and how they are used. The command
    // buffer validation pre-computes this information so that backends with explicit barriers
    // don't have to re-compute it.
    struct SyncScopeResourceUsage {
        std::vector<BufferBase*> buffers;
        std::vector<wgpu::BufferUsage> bufferUsages;

        std::vector<TextureBase*> textures;
        std::vector<TextureSubresourceUsage> textureUsages;

        std::vector<ExternalTextureBase*> externalTextures;
    };

    // Contains all the resource usage data for a compute pass.
    //
    // Essentially a list of SyncScopeResourceUsage, one per Dispatch as required by the WebGPU
    // specification. ComputePassResourceUsage also stores nline the set of all buffers and
    // textures used, because some unused BindGroups may not be used at all in synchronization
    // scope but their resources still need to be validated on Queue::Submit.
    struct ComputePassResourceUsage {
        // Somehow without this defaulted constructor, MSVC or its STDlib have an issue where they
        // use the copy constructor (that's deleted) when doing operations on a
        // vector<ComputePassResourceUsage>
        ComputePassResourceUsage(ComputePassResourceUsage&&) = default;
        ComputePassResourceUsage() = default;

        std::vector<SyncScopeResourceUsage> dispatchUsages;

        // All the resources referenced by this compute pass for validation in Queue::Submit.
        std::set<BufferBase*> referencedBuffers;
        std::set<TextureBase*> referencedTextures;
        std::set<ExternalTextureBase*> referencedExternalTextures;
    };

    // Contains all the resource usage data for a render pass.
    //
    // In the WebGPU specification render passes are synchronization scopes but we also need to
    // track additional data. It is stored for render passes used by a CommandBuffer, but also in
    // RenderBundle so they can be merged into the render passes' usage on ExecuteBundles().
    struct RenderPassResourceUsage : public SyncScopeResourceUsage {
        // Storage to track the occlusion queries used during the pass.
        std::vector<QuerySetBase*> querySets;
        std::vector<std::vector<bool>> queryAvailabilities;
    };

    using RenderPassUsages = std::vector<RenderPassResourceUsage>;
    using ComputePassUsages = std::vector<ComputePassResourceUsage>;

    // Contains a hierarchy of "ResourceUsage" that mirrors the hierarchy of the CommandBuffer and
    // is used for validation and to produce barriers and lazy clears in the backends.
    struct CommandBufferResourceUsage {
        RenderPassUsages renderPasses;
        ComputePassUsages computePasses;

        // Resources used in commands that aren't in a pass.
        std::set<BufferBase*> topLevelBuffers;
        std::set<TextureBase*> topLevelTextures;
        std::set<QuerySetBase*> usedQuerySets;
    };

}  // namespace dawn_native

#endif  // DAWNNATIVE_PASSRESOURCEUSAGE_H