Method SetupScriptObjectVTable

Source/Engine/Scripting/BinaryModule.cpp:452–544

}

NO_SANITIZE_ADDRESS
void ScriptingType::SetupScriptObjectVTable(void* object, ScriptingTypeHandle baseTypeHandle, int32 wrapperIndex)
{
    // Analyze vtable size
    void** vtable = *(void***)object;
    const int32 prefixSize = GetVTablePrefix();
    int32 entriesCount = 0;
    while (vtable[entriesCount] && entriesCount < 200)
        entriesCount++;

    // Calculate total vtable size by adding all implemented interfaces that use virtual methods
    const int32 size = entriesCount * sizeof(void*);
    int32 totalSize = prefixSize + size;
    int32 interfacesCount = 0;
    for (ScriptingTypeHandle e = baseTypeHandle; e;)
    {
        const ScriptingType& eType = e.GetType();
        auto interfaces = eType.Interfaces;
        if (interfaces)
        {
            while (interfaces->InterfaceType)
            {
                auto& interfaceType = interfaces->InterfaceType->GetType();
                if (interfaceType.Interface.SetupScriptObjectVTable)
                {
                    void** vtableInterface = *(void***)((byte*)object + interfaces->VTableOffset);
                    int32 interfaceCount = 0;
                    while (vtableInterface[interfaceCount] && interfaceCount < 200)
                        interfaceCount++;
                    totalSize += prefixSize + interfaceCount * sizeof(void*);
                    interfacesCount++;
                }
                interfaces++;
            }
        }
        e = eType.GetBaseType();
    }

    // Duplicate vtable
    void** scriptVTable = (void**)((byte*)Platform::Allocate(totalSize, 16) + prefixSize);
    Utilities::UnsafeMemoryCopy((byte*)scriptVTable - prefixSize, (byte*)vtable - prefixSize, prefixSize + size);

    // Override vtable entries
    if (interfacesCount)
        Script.InterfacesOffsets = (uint16*)Platform::Allocate(interfacesCount * sizeof(uint16*), 16);
    int32 interfaceOffset = size;
    interfacesCount = 0;
    for (ScriptingTypeHandle e = baseTypeHandle; e;)
    {
        const ScriptingType& eType = e.GetType();

        if (eType.Script.SetupScriptObjectVTable)
        {
            // Override vtable entries for this class
            eType.Script.SetupScriptObjectVTable(Script.ScriptVTable, Script.ScriptVTableBase, scriptVTable, entriesCount, wrapperIndex);
        }

        auto interfaces = eType.Interfaces;