/// <summary>
/// Copies all entities from srcEntityManager and replaces all entities in this EntityManager
/// </summary>
/// <remarks>
/// Gurantees that the chunk layout & order of the entities will match exactly, thus this method can be used for deterministic rollback.
/// This feature is not complete and only supports a subset of the EntityManager features at the moment:
/// * Currently it copies all SystemStateComponents (They should not be copied)
/// * Currently does not support class based components
/// </remarks>
public void CopyAndReplaceEntitiesFrom(EntityManager srcEntityManager)
{
#if ENABLE_UNITY_COLLECTIONS_CHECKS
if (srcEntityManager == null || !srcEntityManager.IsCreated)
{
throw new ArgumentNullException(nameof(srcEntityManager));
}
if (!IsCreated)
{
throw new ArgumentException("This EntityManager has been destroyed");
}
#endif
srcEntityManager.CompleteAllJobs();
CompleteAllJobs();
using (var srcChunks = srcEntityManager.m_UniversalQueryWithChunks.CreateArchetypeChunkArray(Allocator.TempJob))
using (var dstChunks = m_UniversalQueryWithChunks.CreateArchetypeChunkArray(Allocator.TempJob))
{
using (var archetypeChunkChanges = ArchetypeChunkChangeUtility.GetArchetypeChunkChanges(srcChunks, dstChunks, Allocator.TempJob))
{
EntityManagerDifferUtility.CopyAndReplaceChunks(srcEntityManager, this, m_UniversalQueryWithChunks, archetypeChunkChanges);
Unity.Entities.EntityComponentStore.AssertSameEntities(srcEntityManager.EntityComponentStore, EntityComponentStore);
}
}
}
/// <summary>
/// Creates a stateful change tracker over the given world.
/// </summary>
/// <param name="srcWorld">The input world to track changes for.</param>
/// <param name="allocator">Allocator used for the cached state.</param>
public EntityManagerDiffer(World srcWorld, Allocator allocator)
{
m_SrcWorld = srcWorld ?? throw new ArgumentNullException(nameof(srcWorld));
m_ShadowWorld = new World(srcWorld.Name + " (Shadow)");
m_SrcWorldEntityQuery = EntityManagerDifferUtility.CreateQuery(srcWorld.EntityManager);
m_ShadowWorldEntityQuery = EntityManagerDifferUtility.CreateQuery(m_ShadowWorld.EntityManager);
m_TypeInfoStream = new TypeInfoStream(allocator);
}
/// <summary>
/// Generates a detailed change set for the world.
/// All entities to be considered for diffing must have the <see cref="EntityGuid"/> component with a unique value.
/// The resulting <see cref="EntityChanges"/> must be disposed when no longer needed.
/// </summary>
/// <param name="options">A set of options which can be toggled.</param>
/// <param name="allocator">The allocator to use for the results object.</param>
/// <returns>A Change set containing the differences between the two worlds.</returns>
public EntityChanges GetChanges(EntityManagerDifferOptions options, Allocator allocator)
{
s_GetChangesMarker.Begin();
var changes = EntityManagerDifferUtility.GetChanges(
m_SrcWorld.EntityManager,
m_SrcWorldEntityQuery,
m_ShadowWorld.EntityManager,
m_ShadowWorldEntityQuery,
m_TypeInfoStream,
options,
allocator);
s_GetChangesMarker.End();
return(changes);
}