From 3fc4283183374050ef157e8f88fa472d3e712ee8 Mon Sep 17 00:00:00 2001
From: Cyberboss <Cyberboss@users.noreply.github.com>
Date: Sat, 21 Oct 2017 17:08:38 -0400
Subject: [PATCH] Guards the interface DLL copy operation

---
 TGServerService/DreamDaemon.cs   | 31 +++++++++++++++++++++++++++++--
 TGServerService/ServerService.cs |  2 ++
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/TGServerService/DreamDaemon.cs b/TGServerService/DreamDaemon.cs
index ff6fac5c66..c56993a803 100644
--- a/TGServerService/DreamDaemon.cs
+++ b/TGServerService/DreamDaemon.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Diagnostics;
 using System.IO;
+using System.Linq;
 using System.Reflection;
 using System.Threading;
 using System.Timers;
@@ -438,11 +439,37 @@ namespace TGServerService
 
 		void UpdateInterfaceDll(bool overwrite)
 		{
-			if (File.Exists(InterfaceDLLName) && !overwrite)
+			var FileExists = File.Exists(InterfaceDLLName);
+			if (FileExists && !overwrite)
 				return;
 			//Copy the interface dll to the static dir
 			var InterfacePath = Assembly.GetAssembly(typeof(DDInteropCallHolder)).Location;
-			File.Copy(InterfacePath, InterfaceDLLName, overwrite);
+			try
+			{
+				if (FileExists)
+				{
+					var Old = File.ReadAllBytes(InterfaceDLLName);
+					var New = File.ReadAllBytes(InterfacePath);
+					if (Old.SequenceEqual(New))
+						return; //no need
+				}
+				File.Copy(InterfacePath, InterfaceDLLName, overwrite);
+				TGServerService.WriteInfo("Updated interface DLL", TGServerService.EventID.InterfaceDLLUpdated);
+			}
+			catch
+			{
+				try
+				{
+					//ok the things being stupid and hasn't released the dll yet, try ONCE more
+					Thread.Sleep(1000);
+					File.Copy(InterfacePath, InterfaceDLLName, overwrite);
+				}
+				catch (Exception e)
+				{
+					//intentionally using the fi
+					TGServerService.WriteError("Failed to update interface DLL! Error: " + e.ToString(), TGServerService.EventID.InterfaceDLLUpdateFail);
+				}
+			}
 		}
 
 		//used by Start and Watchdog to start a DD instance
diff --git a/TGServerService/ServerService.cs b/TGServerService/ServerService.cs
index f277dfd2f9..426024138f 100644
--- a/TGServerService/ServerService.cs
+++ b/TGServerService/ServerService.cs
@@ -70,6 +70,8 @@ namespace TGServerService
 			RepoPushFail = 5500,
 			RepoChangelog = 5600,
 			RepoChangelogFail = 5700,
+			InterfaceDLLUpdated = 5800,
+			InterfaceDLLUpdateFail = 5900,
 			ServiceShutdownFail = 6100,
 			WorldReboot = 6200,
 			ServerUpdateApplied = 6300,