Added 2 block events and removed BDNEException

Added an event for placing and removing blocks
Added a class to wrap event calls in a try-catch
Removed BlockDoesNotExistException
Made Block.GetSimBody() return null if block doesn't exist

GamecraftModdingAPI/Block.cs

@@ -25,6 +25,7 @@ namespace GamecraftModdingAPI
 		protected static readonly RotationEngine RotationEngine = new RotationEngine();
 		protected static readonly RemovalEngine RemovalEngine = new RemovalEngine();
 		protected static readonly SignalEngine SignalEngine = new SignalEngine();
+		protected static readonly BlockEventsEngine BlockEventsEngine = new BlockEventsEngine();
 		
 		protected internal static readonly BlockEngine BlockEngine = new BlockEngine();
 
@@ -109,17 +110,27 @@ namespace GamecraftModdingAPI
 			return new Block(BlockIdentifiers.LatestBlockID);
 		}
 
+		/// <summary>
+		/// An event that fires each time a block is placed.
+		/// </summary>
+		public static event EventHandler<BlockPlacedRemovedEventArgs> Placed
+		{
+			add => BlockEventsEngine.Placed += value;
+			remove => BlockEventsEngine.Placed -= value;
+		}
+
+		/// <summary>
+		/// An event that fires each time a block is removed.
+		/// </summary>
+		public static event EventHandler<BlockPlacedRemovedEventArgs> Removed
+		{
+			add => BlockEventsEngine.Removed += value;
+			remove => BlockEventsEngine.Removed -= value;
+		}
+
 		public Block(EGID id)
 		{
 			Id = id;
-			if (!BlockEngine.BlockExists(Id))
-            {
-                /*Sync();
-                if (!BlockEngine.BlockExists(Id))
-                {
-					throw new BlockDoesNotExistException($"Block {Id.entityID} must be placed using PlaceNew(...) since it does not exist yet");
-                }*/
-            }
 		}
 
 		public Block(uint id) : this(new EGID(id, CommonExclusiveGroups.OWNED_BLOCKS_GROUP))
@@ -264,11 +275,11 @@ namespace GamecraftModdingAPI
 		/// Returns the rigid body of the cluster of blocks this one belongs to during simulation.
 		/// Can be used to apply forces or move the block around while the simulation is running.
 		/// </summary>
-		/// <returns>The SimBody of the cluster</returns>
+		/// <returns>The SimBody of the cluster or null if the block doesn't exist.</returns>
 		public SimBody GetSimBody()
 		{
-			uint id = BlockEngine.GetBlockInfo<GridConnectionsEntityStruct>(Id).machineRigidBodyId;
-			return new SimBody(id);
+			uint id = BlockEngine.GetBlockInfo<GridConnectionsEntityStruct>(Id, out var exists).machineRigidBodyId;
+			return exists ? new SimBody(id) : null;
 		}
 
 		public override string ToString()
@@ -283,6 +294,7 @@ namespace GamecraftModdingAPI
 			GameEngineManager.AddGameEngine(RotationEngine);
 			GameEngineManager.AddGameEngine(RemovalEngine);
 			GameEngineManager.AddGameEngine(BlockEngine);
+			GameEngineManager.AddGameEngine(BlockEventsEngine);
 		}
 
         /// <summary>

GamecraftModdingAPI/Blocks/BlockEventsEngine.cs

@@ -0,0 +1,42 @@
+using System;
+using GamecraftModdingAPI.Engines;
+using GamecraftModdingAPI.Utility;
+using RobocraftX.Common;
+using Svelto.ECS;
+
+namespace GamecraftModdingAPI.Blocks
+{
+    public class BlockEventsEngine : IReactionaryEngine<DBEntityStruct>
+    {
+        public event EventHandler<BlockPlacedRemovedEventArgs> Placed;
+        public event EventHandler<BlockPlacedRemovedEventArgs> Removed;
+
+        public void Ready()
+        {
+        }
+
+        public EntitiesDB entitiesDB { get; set; }
+        public void Dispose()
+        {
+        }
+
+        public string Name { get; } = "GamecraftModdingAPIBlockEventsEngine";
+        public bool isRemovable { get; } = false;
+
+        public void Add(ref DBEntityStruct entityComponent, EGID egid)
+        {
+            ExceptionUtil.InvokeEvent(Placed, this, new BlockPlacedRemovedEventArgs {ID = egid, Type = (BlockIDs) entityComponent.DBID});
+        }
+
+        public void Remove(ref DBEntityStruct entityComponent, EGID egid)
+        {
+            ExceptionUtil.InvokeEvent(Removed, this, new BlockPlacedRemovedEventArgs {ID = egid, Type = (BlockIDs) entityComponent.DBID});
+        }
+    }
+
+    public struct BlockPlacedRemovedEventArgs
+    {
+        public EGID ID;
+        public BlockIDs Type;
+    }
+}

GamecraftModdingAPI/Blocks/BlockExceptions.cs

@@ -40,15 +40,4 @@ namespace GamecraftModdingAPI.Blocks
 		{
 		}
 	}
-
-	public class BlockDoesNotExistException : BlockException
-	{
-		public BlockDoesNotExistException()
-		{
-		}
-
-		public BlockDoesNotExistException(string message) : base(message)
-		{
-		}
-	}
 }

GamecraftModdingAPI/Tests/GamecraftModdingAPIPluginTest.cs

@@ -226,6 +226,10 @@ namespace GamecraftModdingAPI.Tests
 
 				GameClient.SetDebugInfo("lookedAt", LookedAt);
 				GameClient.SetDebugInfo("InstalledMods", InstalledMods);
+				Block.Placed += (sender, args) =>
+					Logging.MetaDebugLog("Placed block " + args.Type + " with ID " + args.ID);
+				Block.Removed += (sender, args) =>
+					Logging.MetaDebugLog("Removed block " + args.Type + " with ID " + args.ID);
 
                 /*
                 CommandManager.AddCommand(new SimpleCustomCommandEngine<float>((float d) => { UnityEngine.Camera.main.fieldOfView = d; },

GamecraftModdingAPI/Utility/ExceptionUtil.cs

@@ -0,0 +1,29 @@
+using System;
+using GamecraftModdingAPI.Events;
+
+namespace GamecraftModdingAPI.Utility
+{
+    public static class ExceptionUtil
+    {
+        /// <summary>
+        /// Invokes an event in a try-catch block to avoid propagating exceptions.
+        /// </summary>
+        /// <param name="handler">The event to emit, can be null</param>
+        /// <param name="sender">Event sender</param>
+        /// <param name="args">Event arguments</param>
+        /// <typeparam name="T">Type of the event arguments</typeparam>
+        public static void InvokeEvent<T>(EventHandler<T> handler, object sender, T args)
+        {
+            try
+            {
+                handler?.Invoke(sender, args);
+            }
+            catch (Exception e)
+            {
+                EventRuntimeException wrappedException =
+                    new EventRuntimeException($"EventHandler with arg type {typeof(T).Name} threw an exception", e);
+                Logging.LogWarning(wrappedException.ToString());
+            }
+        }
+    }
+}