RefObject.h

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/*
* SPDX-FileCopyrightText: Copyright (c) 2020-2021 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
* SPDX-License-Identifier: MIT
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
 
 
#ifndef NVNEURAL_REFOBJ_H
#define NVNEURAL_REFOBJ_H
 
#if __has_include(<typeinfo>)
#include <typeinfo>
#endif
#include <atomic>
#include <utility>
 
#define NVNEURAL_REFOBJ_REFERENCE_CALLBACKS 0
 
namespace nvneural {
 
ILogger* DefaultLogger(); // forward declaration from CoreHelpers.h
 
namespace refobj {
 
 
struct DisableLifecycleLogging final
{
    struct BaseType {};
 
    template<typename TObject>
    static void* querySingleInterface(IRefObject::TypeId, TObject*)
    {
        return nullptr;
    }
 
    template<typename TObject>
    static const void* querySingleInterface(IRefObject::TypeId, const TObject*)
    {
        return nullptr;
    }
 
    static const bool EnableLogging = false;
};
 
template<typename TBaseType>
struct PublicBase final
{
    using BaseType = TBaseType;
 
 
    template<typename TObject>
    static void* querySingleInterface(IRefObject::TypeId, TObject*)
    {
        return nullptr;
    }
 
    template<typename TObject>
    static const void* querySingleInterface(IRefObject::TypeId, const TObject*)
    {
        return nullptr;
    }
 
 
    static const bool EnableLogging = true;
};
 
template<typename TInterface>
struct Implements final
{
    using BaseType = TInterface;
 
 
    template<typename TObject>
    static void* querySingleInterface(IRefObject::TypeId interfaceId, TObject* me)
    {
        if (interfaceId == InterfaceOf<TInterface>::value)
        {
            return static_cast<TInterface*>(me);
        }
        return nullptr;
    }
 
    template<typename TObject>
    static const void* querySingleInterface(IRefObject::TypeId interfaceId, const TObject* me)
    {
        if (interfaceId == InterfaceOf<TInterface>::value)
        {
            return static_cast<const TInterface*>(me);
        }
        return nullptr;
    }
 
 
    static const bool EnableLogging = true;
};
 
template<typename TInterface, typename TIntermediateType>
struct IndirectlyImplements final
{
    // Sanity-check that TInterface is an indirect base class of TIntermediateType.
    static_assert(std::is_base_of<TInterface, TIntermediateType>::value, "Interface is not a base of the intermediate type");
 
    struct BaseType {};
 
 
    template<typename TObject>
    static void* querySingleInterface(IRefObject::TypeId interfaceId, TObject* me)
    {
        if (interfaceId == InterfaceOf<TInterface>::value)
        {
            return static_cast<TInterface*>(static_cast<TIntermediateType*>(me));
        }
        return nullptr;
    }
 
    template<typename TObject>
    static const void* querySingleInterface(IRefObject::TypeId interfaceId, const TObject* me)
    {
        if (interfaceId == InterfaceOf<TInterface>::value)
        {
            return static_cast<const TInterface*>(static_cast<const TIntermediateType*>(me));
        }
        return nullptr;
    }
 
    static const bool EnableLogging = true;
};
 
 
template<typename... ParameterList>
struct RefObjectBase : public ParameterList::BaseType...
{
    RefObjectBase()
    {
        if (LoggingEnabled)
        {
            logLifetimeChange("%p: Creating", this);
        }
    }
 
    IRefObject::RefCount addRef() const noexcept override
    {
        const auto newRefCount = ++m_refCount;
 
        if (LoggingEnabled)
        {
            logLifetimeChange("%p: %s: Increment ref count to %d", this, thisTypeName(), newRefCount);
        }
 
#if NVNEURAL_REFOBJ_REFERENCE_CALLBACKS
        addRefCallback();
#endif
 
        return newRefCount;
    }
 
    IRefObject::RefCount release() const noexcept override
    {
        const auto newRefCount = --m_refCount;
 
        if (LoggingEnabled)
        {
            logLifetimeChange("%p: %s: Decrement ref count to %d", this, thisTypeName(), newRefCount);
        }
 
#if NVNEURAL_REFOBJ_REFERENCE_CALLBACKS
        releaseCallback();
#endif
        if (!newRefCount)
        {
            if (LoggingEnabled)
            {
                logLifetimeChange("%p: %s: Destroying", this, thisTypeName());
            }
            delete this;
        }
        return newRefCount;
    }
 
    void* queryInterface(IRefObject::TypeId interfaceId) noexcept override
    {
        // Special handling for IRefObject, because we know we support that one
        if (interfaceId == IRefObject::typeID)
        {
            addRef();
            return this;
        }
 
        // Expanding ParameterList into a series of (ParameterList1*) nullptr, (ParameterList2*) nullptr, ...
        // arguments allows us to use a classically recursive queryInterfaceImpl helper function and terminate
        // normally when we get down to zero remaining arguments; parameterizing as qii<PL...>(iid) doesn't
        // allow us to define a termination case; qii<PL...>(iid) and qii(iid) both handle the zero-argument
        // overload scenario and result in ambiguous overload errors.
        const auto pResult = queryInterfaceImpl(interfaceId, static_cast<ParameterList*>(nullptr)...);
        return pResult;
    }
 
    const void* queryInterface(IRefObject::TypeId interfaceId) const noexcept override
    {
        // Special handling for IRefObject, because we know we support that one
        if (interfaceId == IRefObject::typeID)
        {
            addRef();
            return this;
        }
 
        // Expanding ParameterList into a series of (ParameterList1*) nullptr, (ParameterList2*) nullptr, ...
        // arguments allows us to use a classically recursive queryInterfaceImpl helper function and terminate
        // normally when we get down to zero remaining arguments; parameterizing as qii<PL...>(iid) doesn't
        // allow us to define a termination case; qii<PL...>(iid) and qii(iid) both handle the zero-argument
        // overload scenario and result in ambiguous overload errors.
        const auto pResult = queryInterfaceImpl(interfaceId, static_cast<ParameterList*>(nullptr)...);
        return pResult;
    }
 
private:
    template<typename ImplementsHelper, typename... OtherHelpers>
    constexpr static bool enableLoggingImpl(ImplementsHelper* /*thisInterface*/, OtherHelpers... others)
    {
        if (!ImplementsHelper::EnableLogging)
        {
            return false;
        }
        return enableLoggingImpl(others...);
    }
    constexpr static bool enableLoggingImpl()
    {
        return true;
    }
    constexpr static const bool LoggingEnabled = enableLoggingImpl(static_cast<ParameterList*>(nullptr)...);
 
    template<typename ImplementsHelper, typename... OtherHelpers>
    void* queryInterfaceImpl(IRefObject::TypeId interfaceId, ImplementsHelper* /*thisInterface*/, OtherHelpers... others)
    {
        void* const pResult = ImplementsHelper::querySingleInterface(interfaceId, this);
        if (pResult)
        {
            addRef();
            return pResult;
        }
        return queryInterfaceImpl(interfaceId, others...);
    }
 
    template<typename ImplementsHelper, typename... OtherHelpers>
    const void* queryInterfaceImpl(IRefObject::TypeId interfaceId, ImplementsHelper* /*thisInterface*/, OtherHelpers... others) const
    {
        const void* const pResult = ImplementsHelper::querySingleInterface(interfaceId, this);
        if (pResult)
        {
            addRef();
            return pResult;
        }
        return queryInterfaceImpl(interfaceId, others...);
    }
 
    void* queryInterfaceImpl(IRefObject::TypeId)
    {
        return nullptr;
    }
 
    const void* queryInterfaceImpl(IRefObject::TypeId) const
    {
        return nullptr;
    }
 
    template<typename... TFormatArgs>
    static void logLifetimeChange(const char* pFormatString, TFormatArgs... formatArgs)
    {
        const ILogger::VerbosityLevel logVerbosity = 3;
 
        // Even the null DefaultLogger may not have constructed fully yet; it too
        // might be implemented using RefObjectBase.
        if (const auto pLogger = DefaultLogger())
        {
            pLogger->log(logVerbosity, pFormatString, formatArgs...);
        }
    }
 
    const char* thisTypeName() const
    {
#if __cpp_rtti
        // abi::__cxa_demangle in <cxxabi.h> would be interesting here, but
        // involves a round-trip through the dynamic allocator.
        // (There's no way to prevent realloc() from happening on small buffers.)
        // For now, just use obfuscated names in GCC builds. Most top-level (i.e.,
        // not RefObjectBase<X<T>,X<T2>,Y<T3,T4>,...> variant) class names have
        // been fairly easy to recognize in obfuscated form so far.
        return typeid(*this).name();
#else
        // Degrade predictably if RTTI is disabled
        return "<>";
#endif
    }
 
#if NVNEURAL_REFOBJ_REFERENCE_CALLBACKS
    virtual void addRefCallback() const { }
    virtual void releaseCallback() const { }
#endif
 
    mutable std::atomic<IRefObject::RefCount> m_refCount{1u};
};
 
}} // namespace nvneural::refobj
 
#endif // NVNEURAL_REFOBJ_H