EntityExistsFromEntity.cs

using Unity.Collections.LowLevel.Unsafe;

namespace Unity.Entities
{
    [NativeContainer]
    public unsafe struct EntityExistsFromEntity 
    {
#if ENABLE_UNITY_COLLECTIONS_CHECKS
        readonly AtomicSafetyHandle      m_Safety;
#endif
    
        [NativeDisableUnsafePtrRestriction]
        readonly EntityComponentStore*   m_EntityComponentStore;

#if ENABLE_UNITY_COLLECTIONS_CHECKS
        internal EntityExistsFromEntity( EntityComponentStore* store, AtomicSafetyHandle safety )
        {
            m_EntityComponentStore = store;
            m_Safety = safety;
        }    
#else
    internal EntityExistsFromEntity( EntityComponentStore* store )
    {
        m_EntityComponentStore = store;
    }
#endif
    
        public bool Exists(Entity entity)
        {
#if ENABLE_UNITY_COLLECTIONS_CHECKS
            AtomicSafetyHandle.CheckReadAndThrow(m_Safety);
#endif
            return m_EntityComponentStore->Exists(entity);
        }
    }

    public static class EntityExistsExtension
    {
        public static EntityExistsFromEntity GetEntityExistsFromEntity( this ComponentSystemBase system )
        {
            unsafe
            {
                var ecs = system.EntityManager.GetCheckedEntityDataAccess();

#if ENABLE_UNITY_COLLECTIONS_CHECKS
                var safetyHandles = &ecs->DependencyManager->Safety;
                return new EntityExistsFromEntity( ecs->EntityComponentStore, safetyHandles->GetSafetyHandleForEntityTypeHandle( ) );
#else
                return new EntityExistsFromEntity(ecs->EntityComponentStore);
#endif
            }
        }
        
        public static EntityExistsFromEntity GetEntityExistsFromEntity( this EntityManager entityManager )
        {
            unsafe
            {
                var ecs = entityManager.GetCheckedEntityDataAccess();

#if ENABLE_UNITY_COLLECTIONS_CHECKS
                var safetyHandles = &ecs->DependencyManager->Safety;
                return new EntityExistsFromEntity( ecs->EntityComponentStore, safetyHandles->GetSafetyHandleForEntityTypeHandle( ) );
#else
               return new EntityExistsFromEntity(ecs->EntityComponentStore);
#endif
            }
        }
    }
}