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- using System;
- using System.Linq.Expressions;
- using Svelto.DataStructures;
- using Svelto.ECS;
- using Svelto.ECS.Internal;
- using TechbloxModdingAPI.Blocks;
-
- namespace TechbloxModdingAPI
- {
- public abstract class EcsObjectBase
- {
- public abstract EGID Id { get; } //Abstract to support the 'place' Block constructor
-
- protected internal EcsInitData InitData;
-
- /// <summary>
- /// Holds information needed to construct a component initializer
- /// </summary>
- protected internal struct EcsInitData
- {
- private FasterDictionary<RefWrapperType, ITypeSafeDictionary> group;
- private EntityReference reference;
-
- public static implicit operator EcsInitData(EntityInitializer initializer) => new EcsInitData
- {group = GetInitGroup(initializer), reference = initializer.reference};
-
- public EntityInitializer Initializer(EGID id) => new EntityInitializer(id, group, reference);
- public bool Valid => group != null;
- }
-
- private delegate FasterDictionary<RefWrapperType, ITypeSafeDictionary> GetInitGroupFunc(
- EntityInitializer initializer);
-
- /// <summary>
- /// Accesses the group field of the initializer
- /// </summary>
- private static GetInitGroupFunc GetInitGroup = CreateAccessor<GetInitGroupFunc>("_group");
-
- //https://stackoverflow.com/questions/55878525/unit-testing-ref-structs-with-private-fields-via-reflection
- private static TDelegate CreateAccessor<TDelegate>(string memberName) where TDelegate : Delegate
- {
- var invokeMethod = typeof(TDelegate).GetMethod("Invoke");
- if (invokeMethod == null)
- throw new InvalidOperationException($"{typeof(TDelegate)} signature could not be determined.");
-
- var delegateParameters = invokeMethod.GetParameters();
- if (delegateParameters.Length != 1)
- throw new InvalidOperationException("Delegate must have a single parameter.");
-
- var paramType = delegateParameters[0].ParameterType;
-
- var objParam = Expression.Parameter(paramType, "obj");
- var memberExpr = Expression.PropertyOrField(objParam, memberName);
- Expression returnExpr = memberExpr;
- if (invokeMethod.ReturnType != memberExpr.Type)
- returnExpr = Expression.ConvertChecked(memberExpr, invokeMethod.ReturnType);
-
- var lambda =
- Expression.Lambda<TDelegate>(returnExpr, $"Access{paramType.Name}_{memberName}", new[] {objParam});
- return lambda.Compile();
- }
- }
- }
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