src/dawn/wire/client/ObjectBase.h

// Copyright 2019 The Dawn & Tint Authors
//
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// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
//    list of conditions and the following disclaimer.
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// 2. Redistributions in binary form must reproduce the above copyright notice,
//    this list of conditions and the following disclaimer in the documentation
//    and/or other materials provided with the distribution.
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#ifndef SRC_DAWN_WIRE_CLIENT_OBJECTBASE_H_
#define SRC_DAWN_WIRE_CLIENT_OBJECTBASE_H_

#include "dawn/webgpu.h"
#include "partition_alloc/pointers/raw_ptr.h"

#include "dawn/common/LinkedList.h"
#include "dawn/common/Ref.h"
#include "dawn/common/RefCounted.h"
#include "dawn/wire/ObjectHandle.h"
#include "dawn/wire/ObjectType_autogen.h"
#include "dawn/wire/client/EventManager.h"

namespace dawn::wire::client {

class Client;

struct ObjectBaseParams {
    raw_ptr<Client> client;
    ObjectHandle handle;
};

// All objects on the client side have:
//  - A pointer to the Client to get where to serialize commands
//  - The external reference count, starting at 1.
//  - An ID that is used to refer to this object when talking with the server side
//  - A next/prev pointer. They are part of a linked list of objects of the same type.
class ObjectBase : public RefCounted, public LinkNode<ObjectBase> {
  public:
    explicit ObjectBase(const ObjectBaseParams& params);

    virtual void CancelCallbacksForDisconnect() {}
    virtual ObjectType GetObjectType() const = 0;

    // Objects are assumed to be registered with the wire on creation but can be unregistered
    // with Unregister(). After that is done, other ObjectBase getters are invalid to use.
    bool IsRegistered() const;
    void Unregister();

    const ObjectHandle& GetWireHandle() const;
    ObjectId GetWireId() const;
    ObjectGeneration GetWireGeneration() const;
    Client* GetClient() const;

  protected:
    void DeleteThis() override;

  private:
    raw_ptr<Client> mClient;
    const ObjectHandle mHandle;
};

// Compositable functionality for objects on the client side that need to have access to the event
// manager.
class ObjectWithEventsBase : public ObjectBase {
  public:
    // Note that the ObjectHandle associated with an EventManager is the same handle associated to
    // the Instance that "owns" the EventManager.
    ObjectWithEventsBase(const ObjectBaseParams& params, const ObjectHandle& eventManager);

    const ObjectHandle& GetEventManagerHandle() const;
    EventManager& GetEventManager() const;

  private:
    // The EventManager is owned by the client and long-lived. When the client is destroyed all
    // objects are also freed.
    ObjectHandle mEventManagerHandle;
};

template <class T>
auto ReturnToAPI(Ref<T>&& object) {
    if constexpr (T::HasExternalRefCount) {
        // For an object which has external ref count, just need to increase the external ref count,
        // and keep the total ref count unchanged.
        object->IncrementExternalRefCount();
    }
    return ToAPI(object.Detach());
}

}  // namespace dawn::wire::client

#endif  // SRC_DAWN_WIRE_CLIENT_OBJECTBASE_H_