Remove our own impl of ReadOnlyList and update usages

OpenRA.Game/GameRules/Ruleset.cs

@@ -115,7 +115,7 @@ namespace OpenRA
 			if (filterNode != null)
 				yamlNodes = yamlNodes.Where(k => !filterNode(k));
 
-			return new Dictionary<string, T>(yamlNodes.ToDictionaryWithConflictLog(k => k.Key.ToLowerInvariant(), makeObject, "LoadFromManifest<" + name + ">"));
+			return yamlNodes.ToDictionaryWithConflictLog(k => k.Key.ToLowerInvariant(), makeObject, "LoadFromManifest<" + name + ">");
 		}
 
 		public static Ruleset LoadDefaults(ModData modData)

OpenRA.Game/Graphics/HardwarePalette.cs

@@ -21,14 +21,12 @@ namespace OpenRA.Graphics
 		public int Height { get; private set; }
 		readonly Dictionary<string, ImmutablePalette> palettes = new Dictionary<string, ImmutablePalette>();
 		readonly Dictionary<string, MutablePalette> modifiablePalettes = new Dictionary<string, MutablePalette>();
-		readonly IReadOnlyDictionary<string, MutablePalette> readOnlyModifiablePalettes;
 		readonly Dictionary<string, int> indices = new Dictionary<string, int>();
 		byte[] buffer = new byte[0];
 
 		public HardwarePalette()
 		{
 			Texture = Game.Renderer.Context.CreateTexture();
-			readOnlyModifiablePalettes = modifiablePalettes;
 		}
 
 		public bool Contains(string name)
@@ -109,7 +107,7 @@ namespace OpenRA.Graphics
 		public void ApplyModifiers(IEnumerable<IPaletteModifier> paletteMods)
 		{
 			foreach (var mod in paletteMods)
-				mod.AdjustPalette(readOnlyModifiablePalettes);
+				mod.AdjustPalette(modifiablePalettes);
 
 			// Update our texture with the changes.
 			CopyModifiablePalettesToBuffer();

OpenRA.Game/Manifest.cs

@@ -216,8 +216,7 @@ namespace OpenRA
 			if (!yaml.ContainsKey(key))
 				return new Dictionary<string, string>();
 
-			var inner = yaml[key].ToDictionary(my => my.Value);
+			return yaml[key].ToDictionary(my => my.Value);
-			return inner;
 		}
 
 		public bool Contains<T>() where T : IGlobalModData

OpenRA.Game/Network/OrderManager.cs

@@ -52,7 +52,7 @@ namespace OpenRA.Network
 
 		readonly List<ChatLine> chatCache = new List<ChatLine>();
 
-		public readonly ReadOnlyList<ChatLine> ChatCache;
+		public IReadOnlyList<ChatLine> ChatCache => chatCache;
 
 		bool disposed;
 		bool generateSyncReport = false;
@@ -85,7 +85,6 @@ namespace OpenRA.Network
 			Password = password;
 			Connection = conn;
 			syncReport = new SyncReport(this);
-			ChatCache = new ReadOnlyList<ChatLine>(chatCache);
 			AddChatLine += CacheChatLine;
 		}
 

OpenRA.Game/Primitives/ReadOnlyList.cs

@@ -1,81 +0,0 @@
-#region Copyright & License Information
-/*
- * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
- * This file is part of OpenRA, which is free software. It is made
- * available to you under the terms of the GNU General Public License
- * as published by the Free Software Foundation, either version 3 of
- * the License, or (at your option) any later version. For more
- * information, see COPYING.
- */
-#endregion
-
-using System;
-using System.Collections.Generic;
-
-namespace OpenRA
-{
-	/// <summary>
-	/// A minimal read only list interface for .NET 4
-	/// </summary>
-	/// <remarks>
-	/// .NET 4.5 has an implementation built-in, this code is not meant to
-	/// duplicate it but provide a compatible interface that can be replaced
-	/// when we switch to .NET 4.5 or higher.
-	/// </remarks>
-	public interface IReadOnlyList<out T> : IEnumerable<T>
-	{
-		int Count { get; }
-		T this[int index] { get; }
-	}
-
-	public static class ReadOnlyList
-	{
-		public static IReadOnlyList<T> AsReadOnly<T>(this IList<T> list)
-		{
-			return list as IReadOnlyList<T> ?? new ReadOnlyList<T>(list);
-		}
-	}
-
-	/// <summary>
-	/// A minimal read only list for .NET 4 implemented as a wrapper
-	/// around an IList.
-	/// </summary>
-	public class ReadOnlyList<T> : IReadOnlyList<T>
-	{
-		private readonly IList<T> list;
-
-		public ReadOnlyList()
-			: this(new List<T>())
-		{
-		}
-
-		public ReadOnlyList(IList<T> list)
-		{
-			if (list == null)
-				throw new ArgumentNullException(nameof(list));
-
-			this.list = list;
-		}
-
-		#region IEnumerable implementation
-		public IEnumerator<T> GetEnumerator()
-		{
-			return list.GetEnumerator();
-		}
-		#endregion
-
-		#region IEnumerable implementation
-		System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
-		{
-			return list.GetEnumerator();
-		}
-		#endregion
-
-		#region IReadOnlyList implementation
-		public int Count => list.Count;
-
-		public T this[int index] => list[index];
-
-		#endregion
-	}
-}

OpenRA.Mods.Cnc/SpriteLoaders/ShpRemasteredLoader.cs

@@ -10,6 +10,7 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Text.RegularExpressions;
@@ -111,7 +112,7 @@ namespace OpenRA.Mods.Cnc.SpriteLoaders
 				}
 			}
 
-			Frames = frames.AsReadOnly();
+			Frames = frames;
 		}
 	}
 }

OpenRA.Mods.Cnc/SpriteLoaders/ShpTDLoader.cs

@@ -134,7 +134,6 @@ namespace OpenRA.Mods.Cnc.SpriteLoaders
 
 			stream.Position += 4;
 			var headers = new ImageHeader[imageCount];
-			Frames = headers.AsReadOnly();
 			for (var i = 0; i < headers.Length; i++)
 				headers[i] = new ImageHeader(stream, this);
 
@@ -156,6 +155,8 @@ namespace OpenRA.Mods.Cnc.SpriteLoaders
 
 			foreach (var h in headers)
 				Decompress(h);
+
+			Frames = headers;
 		}
 
 		void Decompress(ImageHeader h)

OpenRA.Mods.Cnc/Traits/TDGunboat.cs

@@ -42,8 +42,7 @@ namespace OpenRA.Mods.Cnc.Traits
 
 		public IReadOnlyDictionary<CPos, SubCell> OccupiedCells(ActorInfo info, CPos location, SubCell subCell = SubCell.Any)
 		{
-			var occupied = new Dictionary<CPos, SubCell>() { { location, SubCell.FullCell } };
+			return new Dictionary<CPos, SubCell>() { { location, SubCell.FullCell } };
-			return occupied;
 		}
 
 		bool IOccupySpaceInfo.SharesCell => false;

OpenRA.Mods.Common/SpriteLoaders/DdsLoader.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using OpenRA.Graphics;
@@ -74,7 +75,7 @@ namespace OpenRA.Mods.Common.SpriteLoaders
 
 		public DdsSprite(Stream stream)
 		{
-			Frames = new ISpriteFrame[] { new DdsFrame(stream) }.AsReadOnly();
+			Frames = new ISpriteFrame[] { new DdsFrame(stream) };
 		}
 	}
 }

OpenRA.Mods.Common/SpriteLoaders/TgaLoader.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using OpenRA.Graphics;
@@ -108,7 +109,7 @@ namespace OpenRA.Mods.Common.SpriteLoaders
 
 		public TgaSprite(Stream stream)
 		{
-			Frames = new ISpriteFrame[] { new TgaFrame(stream) }.AsReadOnly();
+			Frames = new ISpriteFrame[] { new TgaFrame(stream) };
 		}
 	}
 }

OpenRA.Mods.Common/Traits/Buildings/Building.cs

@@ -239,10 +239,8 @@ namespace OpenRA.Mods.Common.Traits
 
 		public IReadOnlyDictionary<CPos, SubCell> OccupiedCells(ActorInfo info, CPos topLeft, SubCell subCell = SubCell.Any)
 		{
-			var occupied = OccupiedTiles(topLeft)
+			return OccupiedTiles(topLeft)
 				.ToDictionary(c => c, c => SubCell.FullCell);
-
-			return occupied;
 		}
 
 		bool IOccupySpaceInfo.SharesCell => false;

OpenRA.Mods.Common/Traits/Crates/Crate.cs

@@ -34,8 +34,7 @@ namespace OpenRA.Mods.Common.Traits
 
 		public IReadOnlyDictionary<CPos, SubCell> OccupiedCells(ActorInfo info, CPos location, SubCell subCell = SubCell.Any)
 		{
-			var occupied = new Dictionary<CPos, SubCell>() { { location, SubCell.FullCell } };
+			return new Dictionary<CPos, SubCell>() { { location, SubCell.FullCell } };
-			return occupied;
 		}
 
 		bool IOccupySpaceInfo.SharesCell => false;

OpenRA.Mods.Common/Traits/Husk.cs

@@ -37,8 +37,7 @@ namespace OpenRA.Mods.Common.Traits
 
 		public IReadOnlyDictionary<CPos, SubCell> OccupiedCells(ActorInfo info, CPos location, SubCell subCell = SubCell.Any)
 		{
-			var occupied = new Dictionary<CPos, SubCell>() { { location, SubCell.FullCell } };
+			return new Dictionary<CPos, SubCell>() { { location, SubCell.FullCell } };
-			return occupied;
 		}
 
 		bool IOccupySpaceInfo.SharesCell => false;

OpenRA.Mods.Common/Traits/Immobile.cs

@@ -21,10 +21,8 @@ namespace OpenRA.Mods.Common.Traits
 
 		public IReadOnlyDictionary<CPos, SubCell> OccupiedCells(ActorInfo info, CPos location, SubCell subCell = SubCell.Any)
 		{
-			var occupied = OccupiesSpace ? new Dictionary<CPos, SubCell>() { { location, SubCell.FullCell } } :
+			return OccupiesSpace ? new Dictionary<CPos, SubCell>() { { location, SubCell.FullCell } } :
 				new Dictionary<CPos, SubCell>();
-
-			return occupied;
 		}
 
 		bool IOccupySpaceInfo.SharesCell => false;

OpenRA.Mods.Common/Traits/Player/MissionObjectives.cs

@@ -67,7 +67,7 @@ namespace OpenRA.Mods.Common.Traits
 		public readonly MissionObjectivesInfo Info;
 		readonly List<MissionObjective> objectives = new List<MissionObjective>();
 		readonly Player player;
-		public ReadOnlyList<MissionObjective> Objectives;
+		public IReadOnlyList<MissionObjective> Objectives => objectives;
 
 		Player[] enemies;
 		Player[] allies;
@@ -92,7 +92,6 @@ namespace OpenRA.Mods.Common.Traits
 		{
 			Info = info;
 			this.player = player;
-			Objectives = new ReadOnlyList<MissionObjective>(objectives);
 		}
 
 		void IWorldLoaded.WorldLoaded(World w, WorldRenderer wr)

OpenRA.Mods.Common/Traits/World/EditorActorPreview.cs

@@ -77,12 +77,7 @@ namespace OpenRA.Mods.Common.Traits
 			var radarColorInfo = Info.TraitInfoOrDefault<RadarColorFromTerrainInfo>();
 			RadarColor = radarColorInfo == null ? owner.Color : radarColorInfo.GetColorFromTerrain(world);
 
-			if (ios != null)
+			Footprint = ios?.OccupiedCells(Info, location, subCell) ?? new Dictionary<CPos, SubCell>() { { location, SubCell.FullCell } };
-				Footprint = ios.OccupiedCells(Info, location, subCell);
-			else
-			{
-				Footprint = new Dictionary<CPos, SubCell>() { { location, SubCell.FullCell } };
-			}
 
 			tooltip = Info.TraitInfos<EditorOnlyTooltipInfo>().FirstOrDefault(info => info.EnabledByDefault) as TooltipInfoBase
 				?? Info.TraitInfos<TooltipInfo>().FirstOrDefault(info => info.EnabledByDefault);

OpenRA.Mods.Common/Traits/World/MapOptions.cs

@@ -82,7 +82,7 @@ namespace OpenRA.Mods.Common.Traits
 
 			if (techLevels.Any())
 				yield return new LobbyOption("techlevel", TechLevelDropdownLabel, TechLevelDropdownDescription,	TechLevelDropdownVisible, TechLevelDropdownDisplayOrder,
-					techLevels,	TechLevel, TechLevelDropdownLocked);
+					techLevels, TechLevel, TechLevelDropdownLocked);
 
 			var gameSpeeds = Game.ModData.Manifest.Get<GameSpeeds>().Speeds
 				.ToDictionary(s => s.Key, s => s.Value.Name);