Update IStateManager interface to include the load method and drop unnecessary indexer. This drops support for GreenZone version 0 files, but that was 5 years ago and not really properly done anyway.

Author: SuuperW

src/BizHawk.Client.Common/movie/tasproj/IStateManager.cs

@@ -6,14 +6,6 @@ namespace BizHawk.Client.Common
 {
 	public interface IStateManager : IDisposable
 	{
-		/// <summary>
-		/// Retrieves the savestate for the given frame,
-		/// If this frame does not have a state currently, will return an empty array.false
-		/// Try not to use this as it is not fast.
-		/// </summary>
-		/// <returns>A savestate for the given frame or an empty array if there isn't one</returns>
-		byte[] this[int frame] { get; }
-
 		ZwinderStateManagerSettings Settings { get; }
 
 		/// <summary>
@@ -60,6 +52,11 @@ public interface IStateManager : IDisposable
 		/// </summary>
 		void SaveStateHistory(BinaryWriter bw);
 
+		/// <summary>
+		/// Deserializes the state of the instance that was persisted to disk
+		/// </summary>
+		void LoadStateHistory(BinaryReader br);
+
 		/// <summary>
 		/// Enables the instance to be used. An instance of <see cref="IStateManager"/> should not
 		/// be useable until this method is called

src/BizHawk.Client.Common/movie/tasproj/TasMovie.IO.cs

@@ -154,7 +154,8 @@ private void LoadTasprojExtras(ZipStateLoader bl)
 			{
 				try
 				{
-					TasStateManager = ZwinderStateManager.Create(br, settings, IsReserved);
+					TasStateManager = new ZwinderStateManager(settings, IsReserved);
+					TasStateManager.LoadStateHistory(br);
 				}
 				catch
 				{

src/BizHawk.Client.Common/movie/tasproj/ZwinderStateManager.cs

@@ -63,23 +63,6 @@ private ZwinderStateManager(ZwinderBuffer current, ZwinderBuffer recent, Zwinder
 			RebuildReserved();
 		}
 
-		public byte[] this[int frame]
-		{
-			get
-			{
-				var (f, dataStream) = GetStateClosestToFrame(frame);
-				if (f != frame)
-				{
-					dataStream.Dispose();
-					return NonState;
-				}
-
-				var data = dataStream.ReadAllBytes();
-				dataStream.Dispose();
-				return data;
-			}
-		}
-
 		public ZwinderStateManagerSettings Settings { get; private set; }
 
 		public void UpdateSettings(ZwinderStateManagerSettings settings, bool keepOldStates = false)
@@ -523,32 +506,25 @@ public bool InvalidateAfter(int frame)
 			return b1 || b2 || b3;
 		}
 
-		public static ZwinderStateManager Create(BinaryReader br, ZwinderStateManagerSettings settings, Func<int, bool> reserveCallback)
+		public void LoadStateHistory(BinaryReader br)
 		{
-			// Initial format had no version number, but I think it's a safe bet no valid file has buffer size 2^56 or more so this should work.
 			int version = br.ReadByte();
+			if (version == 0) throw new Exception("Unsupported GreenZone version.");
 
-			var current = ZwinderBuffer.Create(br, settings.Current(), version == 0);
-			var recent = ZwinderBuffer.Create(br, settings.Recent());
-			var gaps = ZwinderBuffer.Create(br, settings.GapFiller());
-
-			if (version == 0)
-				settings.AncientStateInterval = br.ReadInt32();
-
-			var ret = new ZwinderStateManager(current, recent, gaps, reserveCallback, settings);
+			_current.Load(br);
+			_recent.Load(br);
+			_gapFiller.Load(br);
 
 			var ancientCount = br.ReadInt32();
 			for (var i = 0; i < ancientCount; i++)
 			{
 				var key = br.ReadInt32();
 				var length = br.ReadInt32();
 				var data = br.ReadBytes(length);
-				ret._reserved.Add(key, data);
+				_reserved.Add(key, data);
 			}
 
-			ret.RebuildStateCache();
-
-			return ret;
+			RebuildStateCache();
 		}
 
 		public void SaveStateHistory(BinaryWriter bw)

src/BizHawk.Client.Common/rewind/ZwinderBuffer.cs

@@ -1,7 +1,6 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using System.Runtime.InteropServices;
 
 using BizHawk.Common;
 
@@ -343,8 +342,12 @@ private void SaveStateBodyBinary(BinaryWriter writer)
 			}
 		}
 
-		private void LoadStateBodyBinary(BinaryReader reader)
+		public void Load(BinaryReader reader)
 		{
+			int version = reader.ReadByte();
+			if (version != 1)
+				throw new InvalidOperationException("Bad format");
+
 			_firstStateIndex = 0;
 			_nextStateIndex = reader.ReadInt32();
 			long nextByte = 0;
@@ -359,43 +362,6 @@ private void LoadStateBodyBinary(BinaryReader reader)
 			MemoryBlockUtils.CopySome(reader.BaseStream, _backingStore, nextByte);
 		}
 
-		public static ZwinderBuffer Create(BinaryReader reader, RewindConfig rewindConfig, bool hackyV0 = false)
-		{
-			ZwinderBuffer ret;
-
-			// Initial format had no version number, but I think it's a safe bet no valid file has buffer size 2^56 or more so this should work.
-			int version = hackyV0 ? 0 : reader.ReadByte();
-			if (version == 0)
-			{
-				byte[] sizeArr = new byte[8];
-				reader.Read(sizeArr, 1, 7);
-				var size = MemoryMarshal.Read<long>(sizeArr);
-				var sizeMask = reader.ReadInt64();
-				var targetFrameLength = reader.ReadInt32();
-				var useCompression = reader.ReadBoolean();
-				ret = new ZwinderBuffer(new RewindConfig
-				{
-					BufferSize = (int)(size >> 20),
-					UseFixedRewindInterval = false,
-					TargetFrameLength = targetFrameLength,
-					TargetRewindInterval = 5,
-					AllowOutOfOrderStates = false,
-					UseCompression = useCompression,
-				});
-				if (ret.Size != size || ret._sizeMask != sizeMask)
-				{
-					throw new InvalidOperationException("Bad format");
-				}
-			}
-			else if (version == 1)
-				ret = new ZwinderBuffer(rewindConfig);
-			else
-				throw new InvalidOperationException("Bad format");
-
-			ret.LoadStateBodyBinary(reader);
-			return ret;
-		}
-
 		private sealed class SaveStateStream : Stream, ISpanStream
 		{
 			/// <summary>

src/BizHawk.Client.EmuHawk/tools/TAStudio/TAStudio.MenuItems.cs

@@ -661,9 +661,11 @@ private void StateHistoryIntegrityCheckMenuItem_Click(object sender, EventArgs e
 			{
 				MainForm.FrameAdvance();
 
-				byte[] greenZone = CurrentTasMovie.TasStateManager[Emulator.Frame];
-				if (greenZone.Length > 0)
+				if (CurrentTasMovie.TasStateManager.HasState(Emulator.Frame))
 				{
+					Stream greenStream = CurrentTasMovie.TasStateManager.GetStateClosestToFrame(Emulator.Frame).Value;
+					byte[] greenZone = new byte[greenStream.Length];
+					greenStream.Read(greenZone);
 					byte[] state = StatableEmulator.CloneSavestate();
 
 					if (!state.SequenceEqual(greenZone))

src/BizHawk.Tests/Client.Common/Movie/ZwinderStateManagerTests.cs

@@ -71,7 +71,8 @@ public void SaveCreateRoundTrip()
 			var buff = ms.ToArray();
 			var rms = new MemoryStream(buff, false);
 
-			var zw2 = ZwinderStateManager.Create(new BinaryReader(rms), zw.Settings, f => false);
+			var zw2 = new ZwinderStateManager(zw.Settings, f => false);
+			zw2.LoadStateHistory(new BinaryReader(rms));
 
 			// TODO: we could assert more things here to be thorough
 			Assert.IsNotNull(zw2);
@@ -131,7 +132,8 @@ public void SaveCreateBufferRoundTrip()
 			var ms = new MemoryStream();
 			buff.SaveStateBinary(new BinaryWriter(ms));
 			ms.Position = 0;
-			var buff2 = ZwinderBuffer.Create(new BinaryReader(ms), config);
+			var buff2 = new ZwinderBuffer(config);
+			buff2.Load(new BinaryReader(ms));
 
 			Assert.AreEqual(buff.Size, buff2.Size);
 			Assert.AreEqual(buff.Used, buff2.Used);