Lua - implement event.onexit() - fires when the calling script stops execution, supports multiple callbacks per script

BizHawk.Client.Common/lua/EmuLuaLibrary.Events.cs

@@ -21,6 +21,15 @@ namespace BizHawk.Client.Common
 
 		#region Events Library Helpers
 
+		public void CallExitEvent(Lua thread)
+		{
+			var exitCallbacks = _luaFunctions.Where(x => x.Lua == thread && x.Event == "OnExit");
+			foreach (var exitCallback in exitCallbacks)
+			{
+				exitCallback.Call();
+			}
+		}
+
 		public LuaFunctionList RegisteredFunctions { get { return _luaFunctions; } }
 
 		public void CallSaveStateEvent(string name)
@@ -204,6 +213,17 @@ namespace BizHawk.Client.Common
 			return nlf.Guid.ToString();
 		}
 
+		[LuaMethodAttributes(
+			"onexit",
+			"Fires after the calling script has stopped"
+		)]
+		public string OnExit(LuaFunction luaf, string name = null)
+		{
+			var nlf = new NamedLuaFunction(luaf, "OnExit", LogOutputCallback, CurrentThread, name);
+			_luaFunctions.Add(nlf);
+			return nlf.Guid.ToString();
+		}
+
 		[LuaMethodAttributes(
 			"unregisterbyid",
 			"Removes the registered function that matches the guid. If a function is found and remove the function will return true. If unable to find a match, the function will return false."

BizHawk.Client.EmuHawk/tools/Lua/Libraries/EmuLuaLibrary.cs

@@ -111,6 +111,11 @@ namespace BizHawk.Client.EmuHawk
 			_eventLibrary.CallFrameAfterEvent();
 		}
 
+		public void CallExitEvent(Lua thread)
+		{
+			_eventLibrary.CallExitEvent(thread);
+		}
+
 		public void Close()
 		{
 			_lua = new Lua();

BizHawk.Client.EmuHawk/tools/Lua/LuaConsole.cs

@@ -389,6 +389,7 @@ namespace BizHawk.Client.EmuHawk
 								var result = LuaImp.ResumeScript(lf.Thread);
 								if (result.Terminated)
 								{
+									LuaImp.CallExitEvent(lf.Thread);
 									lf.Stop();
 								}
 
@@ -717,6 +718,8 @@ namespace BizHawk.Client.EmuHawk
 				}
 				else if (!item.Enabled && item.Thread != null)
 				{
+					LuaImp.CallExitEvent(item.Thread);
+
 					var items = SelectedItems.ToList();
 					foreach (var sitem in items)
 					{
@@ -730,6 +733,7 @@ namespace BizHawk.Client.EmuHawk
 						UpdateRegisteredFunctionsDialog();
 					}
 
+					LuaImp.CallExitEvent(item.Thread);
 					item.Stop();
 				}
 			}