dawn-cmake/generator/templates/dawn_wire/WireCmd.h

//* 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.

#ifndef DAWNWIRE_WIRECMD_AUTOGEN_H_
#define DAWNWIRE_WIRECMD_AUTOGEN_H_

#include <dawn/webgpu.h>

#include "dawn_wire/ObjectType_autogen.h"

namespace dawn_wire {

    using ObjectId = uint32_t;
    using ObjectGeneration = uint32_t;
    struct ObjectHandle {
      ObjectId id;
      ObjectGeneration generation;

      ObjectHandle();
      ObjectHandle(ObjectId id, ObjectGeneration generation);

      ObjectHandle(const volatile ObjectHandle& rhs);
      ObjectHandle& operator=(const volatile ObjectHandle& rhs);

      // MSVC has a bug where it thinks the volatile copy assignment is a duplicate.
      // Workaround this by forwarding to a different function AssignFrom.
      template <typename T>
      ObjectHandle& operator=(const T& rhs) {
          return AssignFrom(rhs);
      }
      ObjectHandle& AssignFrom(const ObjectHandle& rhs);
      ObjectHandle& AssignFrom(const volatile ObjectHandle& rhs);
    };

    enum class DeserializeResult {
        Success,
        FatalError,
    };

    template <typename BufferT>
    class BufferConsumer {
      public:
        BufferConsumer(BufferT* buffer, size_t size) : mBuffer(buffer), mSize(size) {}

        BufferT* Buffer() const { return mBuffer; }
        size_t AvailableSize() const { return mSize; }

      protected:
        template <typename T, typename N>
        DAWN_NO_DISCARD bool NextN(N count, T** data);

        template <typename T>
        DAWN_NO_DISCARD bool Next(T** data);

        template <typename T>
        DAWN_NO_DISCARD bool Peek(T** data);

      private:
        BufferT* mBuffer;
        size_t mSize;
    };

    class SerializeBuffer : public BufferConsumer<char> {
      public:
        using BufferConsumer::BufferConsumer;
        using BufferConsumer::NextN;
        using BufferConsumer::Next;
    };

    class DeserializeBuffer : public BufferConsumer<const volatile char> {
      public:
        using BufferConsumer::BufferConsumer;

        template <typename T, typename N>
        DAWN_NO_DISCARD DeserializeResult ReadN(N count, const volatile T** data) {
            return NextN(count, data)
                ? DeserializeResult::Success
                : DeserializeResult::FatalError;
        }

        template <typename T>
        DAWN_NO_DISCARD DeserializeResult Read(const volatile T** data) {
            return Next(data)
                ? DeserializeResult::Success
                : DeserializeResult::FatalError;
        }

        template <typename T>
        DAWN_NO_DISCARD DeserializeResult Peek(const volatile T** data) {
            return BufferConsumer::Peek(data)
                ? DeserializeResult::Success
                : DeserializeResult::FatalError;
        }
    };

    // Interface to allocate more space to deserialize pointed-to data.
    // nullptr is treated as an error.
    class DeserializeAllocator {
        public:
            virtual void* GetSpace(size_t size) = 0;
    };

    // Interface to convert an ID to a server object, if possible.
    // Methods return FatalError if the ID is for a non-existent object and Success otherwise.
    class ObjectIdResolver {
        public:
            {% for type in by_category["object"] %}
                virtual DeserializeResult GetFromId(ObjectId id, {{as_cType(type.name)}}* out) const = 0;
                virtual DeserializeResult GetOptionalFromId(ObjectId id, {{as_cType(type.name)}}* out) const = 0;
            {% endfor %}
    };

    // Interface to convert a client object to its ID for the wiring.
    class ObjectIdProvider {
        public:
            {% for type in by_category["object"] %}
                virtual ObjectId GetId({{as_cType(type.name)}} object) const = 0;
                virtual ObjectId GetOptionalId({{as_cType(type.name)}} object) const = 0;
            {% endfor %}
    };

    //* Enum used as a prefix to each command on the wire format.
    enum class WireCmd : uint32_t {
        {% for command in cmd_records["command"] %}
            {{command.name.CamelCase()}},
        {% endfor %}
    };

    //* Enum used as a prefix to each command on the return wire format.
    enum class ReturnWireCmd : uint32_t {
        {% for command in cmd_records["return command"] %}
            {{command.name.CamelCase()}},
        {% endfor %}
    };

    struct CmdHeader {
        uint64_t commandSize;
    };

{% macro write_command_struct(command, is_return_command) %}
    {% set Return = "Return" if is_return_command else "" %}
    {% set Cmd = command.name.CamelCase() + "Cmd" %}
    struct {{Return}}{{Cmd}} {
        //* From a filled structure, compute how much size will be used in the serialization buffer.
        size_t GetRequiredSize() const;

        //* Serialize the structure and everything it points to into serializeBuffer which must be
        //* big enough to contain all the data (as queried from GetRequiredSize).
        DAWN_NO_DISCARD bool Serialize(size_t commandSize, SerializeBuffer* serializeBuffer
            {%- if not is_return_command -%}
                , const ObjectIdProvider& objectIdProvider
            {%- endif -%}
        ) const;

        //* Deserializes the structure from a buffer, consuming a maximum of *size bytes. When this
        //* function returns, buffer and size will be updated by the number of bytes consumed to
        //* deserialize the structure. Structures containing pointers will use allocator to get
        //* scratch space to deserialize the pointed-to data.
        //* Deserialize returns:
        //*  - Success if everything went well (yay!)
        //*  - FatalError is something bad happened (buffer too small for example)
        DeserializeResult Deserialize(DeserializeBuffer* deserializeBuffer, DeserializeAllocator* allocator
            {%- if command.may_have_dawn_object -%}
                , const ObjectIdResolver& resolver
            {%- endif -%}
        );

        {% if command.derived_method %}
            //* Command handlers want to know the object ID in addition to the backing object.
            //* Doesn't need to be filled before Serialize, or GetRequiredSize.
            ObjectId selfId;
        {% endif %}

        {% for member in command.members %}
            {{as_annotated_cType(member)}};
        {% endfor %}
    };
{% endmacro %}

    {% for command in cmd_records["command"] %}
        {{write_command_struct(command, False)}}
    {% endfor %}

    {% for command in cmd_records["return command"] %}
        {{write_command_struct(command, True)}}
    {% endfor %}

}  // namespace dawn_wire

#endif // DAWNWIRE_WIRECMD_AUTOGEN_H_