Support loading mods from arbitrary locations.

OpenRA.Game/Game.cs

@@ -244,6 +244,16 @@ namespace OpenRA
 		{
 			Console.WriteLine("Platform is {0}", Platform.CurrentPlatform);
 
+			// Special case handling of Game.Mod argument: if it matches a real filesystem path
+			// then we use this to override the mod search path, and replace it with the mod id
+			var modArgument = args.GetValue("Game.Mod", null);
+			string customModPath = null;
+			if (modArgument != null && (File.Exists(modArgument) || Directory.Exists(modArgument)))
+			{
+				customModPath = modArgument;
+				args.ReplaceValue("Game.Mod", Path.GetFileNameWithoutExtension(modArgument));
+			}
+
 			InitializeSettings(args);
 
 			Log.AddChannel("perf", "perf.log");
@@ -303,7 +313,7 @@ namespace OpenRA
 
 			GlobalChat = new GlobalChat();
 
-			Mods = new InstalledMods();
+			Mods = new InstalledMods(customModPath);
 			Console.WriteLine("Available mods:");
 			foreach (var mod in Mods)
 				Console.WriteLine("\t{0}: {1} ({2})", mod.Key, mod.Value.Metadata.Title, mod.Value.Metadata.Version);

OpenRA.Game/InstalledMods.cs

@@ -23,9 +23,9 @@ namespace OpenRA
 	{
 		readonly Dictionary<string, Manifest> mods;
 
-		public InstalledMods()
+		public InstalledMods(string customModPath)
 		{
-			mods = GetInstalledMods();
+			mods = GetInstalledMods(customModPath);
 		}
 
 		static IEnumerable<Pair<string, string>> GetCandidateMods()
@@ -89,10 +89,14 @@ namespace OpenRA
 			}
 		}
 
-		static Dictionary<string, Manifest> GetInstalledMods()
+		static Dictionary<string, Manifest> GetInstalledMods(string customModPath)
 		{
 			var ret = new Dictionary<string, Manifest>();
-			foreach (var pair in GetCandidateMods())
+			var candidates = GetCandidateMods();
+			if (customModPath != null)
+				candidates = candidates.Append(Pair.New(Path.GetFileNameWithoutExtension(customModPath), customModPath));
+
+			foreach (var pair in candidates)
 			{
 				var mod = LoadMod(pair.First, pair.Second);
 

OpenRA.Game/Support/Arguments.cs

@@ -35,5 +35,6 @@ namespace OpenRA
 
 		public bool Contains(string key) { return args.ContainsKey(key); }
 		public string GetValue(string key, string defaultValue) { return Contains(key) ? args[key] : defaultValue; }
+		public void ReplaceValue(string key, string value) { args[key] = value; }
 	}
 }