serialize.h

// Copyright 2009-2025 NTESS. Under the terms
// of Contract DE-NA0003525 with NTESS, the U.S.
// Government retains certain rights in this software.
//
// Copyright (c) 2009-2025, NTESS
// All rights reserved.
//
// This file is part of the SST software package. For license
// information, see the LICENSE file in the top level directory of the
// distribution.

#ifndef SST_CORE_SERIALIZATION_SERIALIZE_H
#define SST_CORE_SERIALIZATION_SERIALIZE_H

#include "sst/core/from_string.h"
#include "sst/core/serialization/objectMap.h"
#include "sst/core/serialization/serializer.h"
#include "sst/core/warnmacros.h"

#define SST_INCLUDING_SERIALIZE_H
#include "sst/core/serialization/impl/serialize_utility.h"
#undef SST_INCLUDING_SERIALIZE_H

#include <atomic>
#include <cstdint>
#include <iostream>
#include <type_traits>
#include <typeinfo>

/**
   Macro used in serialize_impl<> template specializations to
   correctly friend the serialize<> template.  The operator() function
   should be private in the serialize_impl<> implementations.

   NOTE: requires a semicolon after the call
 */
#define SST_FRIEND_SERIALIZE() \
    template <class SER>       \
    friend class pvt::serialize

namespace SST {

/**
    Types for options passed to serialization.  Putting in a higher
    namespace to ease use by shortening the fully qualified names
**/

/**
   Type used to pass serialization options
*/
using ser_opt_t = uint32_t;

struct SerOption
{
    /**
       Options use to control how serialization acts for specific
       elements that are serialized
    */
    enum Options : ser_opt_t {
        // No set options
        none          = 0,
        // Used to track the address of a non-pointer object when pointer
        // tracking is on
        as_ptr        = 1u << 1,
        // Used to pass the as_ptr option to the contents of a container
        // when serialized
        as_ptr_elem   = 1u << 2,
        // Used to specify a variable should be read-only in mapping mode
        map_read_only = 1u << 3,
        // Used to specify a variable should not be available in
        // mapping mode
        no_map        = 1u << 4,
        // User defined options are not currently supported
    };

    // Function to test if an options for serialization is
    // set. Function marked constexpr so that it can evaluate at
    // compile time if all values are available. Return type must
    // match SST::Core::Serialization::ser_opt_t
    static constexpr bool is_set(ser_opt_t flags, SerOption::Options option)
    {
        return flags & static_cast<ser_opt_t>(option);
    }
};

namespace Core::Serialization {

template <typename T>
void sst_ser_object(serializer& ser, T&& obj, ser_opt_t options, const char* name);

// get_ptr() returns reference to argument if it's a pointer, else address of argument
template <typename T>
constexpr decltype(auto)
get_ptr(T& t)
{
    if constexpr ( std::is_pointer_v<T> )
        return t;
    else
        return &t;
}


/**
   Base serialize class.

   This class also acts as the default case, which if hit will check
   to see if this is an otherwise unhandled non-polymorphic class. If
   it is, it will just attempt to call the serialize_order() function.
   All other instances are partial specializations of this class and
   do all the real serialization.
 */
template <typename T, typename = void>
class serialize_impl
{
    static_assert(std::is_class_v<std::remove_pointer_t<T>>,
        "Trying to serialize a non-class type (or a pointer to one) with the default serialize_impl.");

    static_assert(std::is_final_v<std::remove_pointer_t<T>> || !std::is_polymorphic_v<std::remove_pointer_t<T>>,
        "The type or the pointed-to-type is polymorphic and non-final, so serialize_impl cannot know the runtime type "
        "of the object being serialized. Polymorphic classes need to inherit from the serializable class and call the "
        "ImplementSerializable() macro. For classes marked final, this is not necessary.");

    static_assert(has_serialize_order_v<std::remove_pointer_t<T>>,
        "The type or the pointed-to-type does not have a serialize_impl specialization, nor a public "
        "serialize_order() method. This means that there is not a serialize_impl class specialization for "
        "the type or a pointer to the type, and so the default serialize_impl is used which requires a "
        "public serialize_order() method to be defined inside of the class type.");

public:
    void operator()(T& t, serializer& ser, ser_opt_t UNUSED(options))
    {
        const auto& tPtr = get_ptr(t);
        const auto  mode = ser.mode();
        if ( mode == serializer::MAP ) {
            if ( !tPtr ) return; // No need to map a nullptr
            ObjectMap* map = new ObjectMapClass(tPtr, typeid(T).name());
            ser.mapper().report_object_map(map);
            ser.mapper().map_hierarchy_start(ser.getMapName(), map);
        }
        else if constexpr ( std::is_pointer_v<T> ) {
            if ( mode == serializer::UNPACK ) {
                t = new std::remove_pointer_t<T>();
                ser.unpacker().report_new_pointer(reinterpret_cast<uintptr_t>(t));
            }
        }

        // class needs to define a serialize_order() method
        tPtr->serialize_order(ser);

        if ( mode == serializer::MAP ) ser.mapper().map_hierarchy_end();
    }
};

namespace pvt {

/**
   Serialization "gateway" object called by sst_ser_object().  All
   serializations must come through these template instances in order
   for pointer tracking to be controlled at one point. The actual
   serialization will happen in serialize_impl classes.
 */
template <class T>
class serialize
{
    template <class U>
    friend void SST::Core::Serialization::sst_ser_object(serializer& ser, U&& obj, ser_opt_t options, const char* name);

    void operator()(T& t, serializer& ser, ser_opt_t options) { return serialize_impl<T>()(t, ser, options); }

    /**
       This will track the pointer to the object if pointer tracking
       is turned on. Otherwise, it will just serialize normally.  This
       is only useful if you have a non-pointer struct/class where
       other pieces of code will have pointers to it (e.g. a set/map
       contains the actual struct and other places point to the data's
       location)
     */
    void serialize_and_track_pointer(T& t, serializer& ser, ser_opt_t options)
    {
        if ( !ser.is_pointer_tracking_enabled() ) return serialize_impl<T>()(t, ser, options);

        // Get the pointer to the data that will be uesd for tracking.
        uintptr_t ptr = reinterpret_cast<uintptr_t>(&t);

        switch ( ser.mode() ) {
        case serializer::SIZER:
            // Check to see if the pointer has already been seen.  If
            // so, then we error since the non-pointer version of this
            // data needs to be serialized before any of the pointers
            // that point to it.
            if ( ser.sizer().check_pointer_sizer(ptr) ) {
                // TODO Error
            }

            // Always put the pointer in
            ser.size(ptr);
            // Count the data for the object
            serialize_impl<T>()(t, ser, options);
            break;
        case serializer::PACK:
            // Already checked serialization order during sizing, so
            // don't need to do it here
            ser.packer().check_pointer_pack(ptr);
            // Always put the pointer in
            ser.pack(ptr);
            // Serialize the data for the object
            serialize_impl<T>()(t, ser, options);
            break;
        case serializer::UNPACK:
            // Checked order on serialization, so don't need to do it
            // here

            // Get the stored pointer to use as a tag for future
            // references to the data
            uintptr_t ptr_stored;
            ser.unpack(ptr_stored);

            // Now add this to the tracking data
            ser.unpacker().report_real_pointer(ptr_stored, ptr);

            serialize_impl<T>()(t, ser, options);
            break;
        case serializer::MAP:
            serialize_impl<T>()(t, ser, options);
            break;
        }
    }
};

template <class T>
class serialize<T*>
{
    template <class U>
    friend void SST::Core::Serialization::sst_ser_object(serializer& ser, U&& obj, ser_opt_t options, const char* name);
    void        operator()(T*& t, serializer& ser, ser_opt_t options)
    {
        // We are a pointer, need to see if tracking is turned on
        if ( !ser.is_pointer_tracking_enabled() ) {
            switch ( ser.mode() ) {
            case serializer::UNPACK:
                t = nullptr; // Nullify the pointer in case it was null
                [[fallthrough]];
            default:
            {
                // We will always get/put a bool to tell whether or not this is nullptr.
                bool nonnull = t != nullptr;
                ser.primitive(nonnull);

                // If not nullptr, serialize the object
                if ( nonnull ) serialize_impl<T*>()(t, ser, options);
                break;
            }
            case serializer::MAP:
                break; // If this version of serialize gets called in mapping mode, there is nothing to do
            }
            return;
        }

        uintptr_t ptr = reinterpret_cast<uintptr_t>(t);
        if ( nullptr == t ) ptr = 0;

        switch ( ser.mode() ) {
        case serializer::SIZER:
            // Always put the pointer in
            ser.size(ptr);

            // If this is a nullptr, then we are done
            if ( 0 == ptr ) return;

            // If we haven't seen this yet, also need to serialize the
            // object
            if ( !ser.sizer().check_pointer_sizer(ptr) ) {
                serialize_impl<T*>()(t, ser, options);
            }
            break;
        case serializer::PACK:
            // Always put the pointer in
            ser.pack(ptr);

            // Nothing else to do if this is nullptr
            if ( 0 == ptr ) return;

            if ( !ser.packer().check_pointer_pack(ptr) ) {
                serialize_impl<T*>()(t, ser, options);
            }
            break;
        case serializer::UNPACK:
        {
            // Get the ptr and check to see if we've already deserialized
            uintptr_t ptr_stored;
            ser.unpack(ptr_stored);

            // Check to see if this was a nullptr
            if ( 0 == ptr_stored ) {
                t = nullptr;
                return;
            }

            uintptr_t real_ptr = ser.unpacker().check_pointer_unpack(ptr_stored);
            if ( real_ptr ) {
                // Already deserialized, so just return pointer
                t = reinterpret_cast<T*>(real_ptr);
            }
            else {
                serialize_impl<T*>()(t, ser, options);
                ser.unpacker().report_real_pointer(ptr_stored, reinterpret_cast<uintptr_t>(t));
            }
            break;
        }
        case serializer::MAP:
        {
            ObjectMap* map = ser.mapper().check_pointer_map(reinterpret_cast<uintptr_t>(t));
            if ( map != nullptr ) {
                // If we've already seen this object, just add the
                // existing ObjectMap to the parent.
                ser.mapper().map_existing_object(ser.getMapName(), map);
            }
            else {
                serialize_impl<T*>()(t, ser, options);
            }
            break;
        }
        }
    }
};

} // namespace pvt

// All serialization must go through this function to ensure
// everything works correctly
//
// A universal/forwarding reference is used for obj so that it can match rvalue wrappers like
// SST::Core::Serialization::array(ary, size) but then it is used as an lvalue so that it
// matches serialization functions which only take lvalue references.
template <class TREF>
void
sst_ser_object(serializer& ser, TREF&& obj, ser_opt_t options, const char* name)
{
    // TREF is an lvalue reference when obj argument is an lvalue reference, so we remove the reference
    using T = std::remove_reference_t<TREF>;

    // We will check for the "fast" path (i.e. event serialization for synchronizations).  We can detect this by
    // seeing if pointer tracking is turned off, because it is turned on for both checkpointing and mapping mode.
    if ( !ser.is_pointer_tracking_enabled() ) {
        // Options are wiped out since none apply in this case
        return pvt::serialize<T>()(obj, ser, SerOption::none);
    }

    // Mapping mode
    if ( ser.mode() == serializer::MAP ) {
        ObjectMapContext context(ser, name);
        // Check to see if we are NOMAP
        if ( SerOption::is_set(options, SerOption::no_map) ) return;

        pvt::serialize<T>()(obj, ser, options);
        return;
    }

    if constexpr ( !std::is_pointer_v<T> ) {
        // as_ptr is only valid for non-pointers
        if ( SerOption::is_set(options, SerOption::as_ptr) ) {
            pvt::serialize<T>().serialize_and_track_pointer(obj, ser, options);
        }
        else {
            pvt::serialize<T>()(obj, ser, options);
        }
    }
    else {
        // For pointer types, just call serialize
        pvt::serialize<T>()(obj, ser, options);
    }
}

// A universal/forwarding reference is used for obj so that it can match rvalue wrappers like
// SST::Core::Serialization::array(ary, size) but then it is used as an lvalue so that it
// matches serialization functions which only take lvalue references.
template <class T>
[[deprecated("The ser& syntax for serialization has been deprecated and will be removed in SST 16.  Please use the "
             "SST_SER macro for serializing data. The macro supports additional options to control the details of "
             "serialization.  See the SerOption enum for details.")]]
void
operator&(serializer& ser, T&& obj)
{
    SST::Core::Serialization::sst_ser_object(ser, obj, SerOption::no_map, "");
}

template <class T>
[[deprecated("The ser| syntax for serialization has been deprecated and will be removed in SST 16.  Please use the "
             "SST_SER macro with the SerOption::as_ptr flag for serializing data. The macro supports additional "
             "options to control the details of serialization.  See the SerOption enum for details.")]]
void
operator|(serializer& ser, T&& obj)
{
    SST::Core::Serialization::sst_ser_object(ser, obj, SerOption::no_map | SerOption::as_ptr, "");
}


// Serialization macros for checkpoint/debug serialization
#define SST_SER(obj, ...)                     \
    SST::Core::Serialization::sst_ser_object( \
        ser, (obj), SST::Core::Serialization::pvt::sst_ser_or_helper(__VA_ARGS__), #obj)

#define SST_SER_NAME(obj, name, ...)          \
    SST::Core::Serialization::sst_ser_object( \
        ser, (obj), SST::Core::Serialization::pvt::sst_ser_or_helper(__VA_ARGS__), name)


// #define SST_SER_AS_PTR(obj) (ser | (obj));

namespace pvt {
template <typename... Args>
constexpr ser_opt_t
sst_ser_or_helper(Args... args)
{
    return (SerOption::none | ... | args); // Fold expression to perform logical OR
}

} // namespace pvt
} // namespace Core::Serialization
} // namespace SST

// These includes have guards to print warnings if they are included independent of this file.
// Set the #define that will disable the warnings.
#define SST_INCLUDING_SERIALIZE_H
#include "sst/core/serialization/impl/serialize_adapter.h"
#include "sst/core/serialization/impl/serialize_aggregate.h"
#include "sst/core/serialization/impl/serialize_array.h"
#include "sst/core/serialization/impl/serialize_atomic.h"
#include "sst/core/serialization/impl/serialize_bitset.h"
#include "sst/core/serialization/impl/serialize_insertable.h"
#include "sst/core/serialization/impl/serialize_optional.h"
// Disable until more stable across platforms
// #include "sst/core/serialization/impl/serialize_shared_ptr.h"
#include "sst/core/serialization/impl/serialize_string.h"
#include "sst/core/serialization/impl/serialize_trivial.h"
#include "sst/core/serialization/impl/serialize_tuple.h"
#include "sst/core/serialization/impl/serialize_unique_ptr.h"
#include "sst/core/serialization/impl/serialize_valarray.h"
#include "sst/core/serialization/impl/serialize_variant.h"

// Reenble warnings for including the above file independent of this file.
#undef SST_INCLUDING_SERIALIZE_H

#endif // SST_CORE_SERIALIZATION_SERIALIZE_H