Use IPC via TCP

osu.Desktop/LegacyIpc/LegacyIpcDifficultyCalculationRequest.cs

@@ -0,0 +1,18 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+namespace osu.Desktop.LegacyIpc
+{
+    /// <summary>
+    /// A difficulty calculation request from the legacy client.
+    /// </summary>
+    /// <remarks>
+    /// Synchronise any changes with osu!stable.
+    /// </remarks>
+    public class LegacyIpcDifficultyCalculationRequest
+    {
+        public string BeatmapFile { get; set; }
+        public int RulesetId { get; set; }
+        public int Mods { get; set; }
+    }
+}

osu.Desktop/LegacyIpc/LegacyIpcDifficultyCalculationResponse.cs

@@ -0,0 +1,16 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+namespace osu.Desktop.LegacyIpc
+{
+    /// <summary>
+    /// A difficulty calculation response returned to the legacy client.
+    /// </summary>
+    /// <remarks>
+    /// Synchronise any changes with osu!stable.
+    /// </remarks>
+    public class LegacyIpcDifficultyCalculationResponse
+    {
+        public double StarRating { get; set; }
+    }
+}

osu.Desktop/LegacyIpc/LegacyIpcMessage.cs

@@ -0,0 +1,40 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using osu.Framework.Platform;
+
+namespace osu.Desktop.LegacyIpc
+{
+    /// <summary>
+    /// An <see cref="IpcMessage"/> that can be used to communicate to and from legacy clients.
+    /// </summary>
+    /// <remarks>
+    /// Synchronise any changes with osu-stable.
+    /// </remarks>
+    public class LegacyIpcMessage : IpcMessage
+    {
+        public LegacyIpcMessage()
+        {
+            // Types/assemblies are not inter-compatible, so always serialise/deserialise into objects.
+            base.Type = typeof(object).FullName;
+        }
+
+        public new string Type => base.Type; // Hide setter.
+
+        public new object Value
+        {
+            get => base.Value;
+            set => base.Value = new Data
+            {
+                MessageType = value.GetType().Name,
+                MessageData = value
+            };
+        }
+
+        public class Data
+        {
+            public string MessageType { get; set; }
+            public object MessageData { get; set; }
+        }
+    }
+}

osu.Desktop/LegacyIpc/LegacyTcpIpcProvider.cs

@@ -0,0 +1,65 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using System.Threading.Tasks;
+using Newtonsoft.Json.Linq;
+using osu.Framework.Platform;
+
+namespace osu.Desktop.LegacyIpc
+{
+    public class LegacyTcpIpcProvider : TcpIpcProvider
+    {
+        public new Func<object, object> MessageReceived;
+
+        public LegacyTcpIpcProvider()
+        {
+            base.MessageReceived += msg =>
+            {
+                try
+                {
+                    var legacyData = ((JObject)msg.Value).ToObject<LegacyIpcMessage.Data>();
+                    object value = parseObject((JObject)legacyData.MessageData, legacyData.MessageType);
+
+                    object result = MessageReceived?.Invoke(value);
+                    return result != null ? new LegacyIpcMessage { Value = result } : null;
+                }
+                catch (Exception ex)
+                {
+                    Console.WriteLine(ex);
+                }
+
+                return null;
+            };
+        }
+
+        public Task SendMessageAsync(object message) => base.SendMessageAsync(new LegacyIpcMessage { Value = message });
+
+        public async Task<T> SendMessageWithResponseAsync<T>(object message)
+        {
+            var result = await base.SendMessageWithResponseAsync(new LegacyIpcMessage { Value = message }).ConfigureAwait(false);
+
+            var legacyData = ((JObject)result.Value).ToObject<LegacyIpcMessage.Data>();
+            return (T)parseObject((JObject)legacyData.MessageData, legacyData.MessageType);
+        }
+
+        public new Task SendMessageAsync(IpcMessage message) => throw new InvalidOperationException("Use typed overloads.");
+
+        public new Task<IpcMessage> SendMessageWithResponseAsync(IpcMessage message) => throw new InvalidOperationException("Use typed overloads.");
+
+        private object parseObject(JObject value, string type)
+        {
+            switch (type)
+            {
+                case nameof(LegacyIpcDifficultyCalculationRequest):
+                    return value.ToObject<LegacyIpcDifficultyCalculationRequest>();
+
+                case nameof(LegacyIpcDifficultyCalculationResponse):
+                    return value.ToObject<LegacyIpcDifficultyCalculationResponse>();
+
+                default:
+                    throw new ArgumentException($"Unknown type: {type}");
+            }
+        }
+    }
+}

osu.Desktop/Program.cs

@@ -6,6 +6,7 @@ using System.IO;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
+using osu.Desktop.LegacyIpc;
 using osu.Framework;
 using osu.Framework.Development;
 using osu.Framework.Logging;
@@ -27,6 +28,8 @@ namespace osu.Desktop
     {
         private const string base_game_name = @"osu";
 
+        private static LegacyTcpIpcProvider legacyIpcProvider;
+
         [STAThread]
         public static void Main(string[] args)
         {
@@ -59,33 +62,26 @@ namespace osu.Desktop
                         gameName = $"{base_game_name}-{clientID}";
                         break;
 
-                    case "--osu-stable-difficulty-stream":
-                        while (true)
+                    case "--legacy-ipc-server":
+                        using (legacyIpcProvider = new LegacyTcpIpcProvider())
                         {
-                            try
-                            {
-                                string beatmapFile = Console.ReadLine() ?? string.Empty;
-                                int rulesetId = int.Parse(Console.ReadLine() ?? string.Empty);
-                                LegacyMods legacyMods = (LegacyMods)int.Parse(Console.ReadLine() ?? string.Empty);
-
-                                Ruleset ruleset = rulesetId switch
-                                {
-                                    0 => new OsuRuleset(),
-                                    1 => new TaikoRuleset(),
-                                    2 => new CatchRuleset(),
-                                    3 => new ManiaRuleset(),
-                                    _ => throw new ArgumentException("Invalid ruleset id")
-                                };
-
-                                Mod[] mods = ruleset.ConvertFromLegacyMods(legacyMods).ToArray();
-                                WorkingBeatmap beatmap = new FlatFileWorkingBeatmap(beatmapFile, _ => ruleset);
-                                Console.WriteLine(ruleset.CreateDifficultyCalculator(beatmap).Calculate(mods).StarRating);
-                            }
-                            catch
-                            {
-                                Console.WriteLine(0);
-                            }
+                            legacyIpcProvider.MessageReceived += onLegacyIpcMessageReceived;
+                            legacyIpcProvider.Bind();
+                            legacyIpcProvider.StartAsync().Wait();
                         }
+
+                        return;
+
+                    case "--legacy-ipc-client":
+                        using (legacyIpcProvider = new LegacyTcpIpcProvider())
+                        {
+                            Console.WriteLine(legacyIpcProvider.SendMessageWithResponseAsync<LegacyIpcDifficultyCalculationResponse>(new LegacyIpcDifficultyCalculationRequest
+                            {
+                                BeatmapFile = "/home/smgi/Downloads/osu_files/129891.osu",
+                            }).Result.StarRating);
+                        }
+
+                        return;
                 }
             }
 
@@ -141,13 +137,39 @@ namespace osu.Desktop
 
             return continueExecution;
         }
-    }
 
-    // Note: Keep in osu.Desktop namespace, or update osu!stable also.
-    public class DifficultyCalculationMessage
-    {
-        public string BeatmapFile { get; set; }
-        public int RulesetId { get; set; }
-        public int Mods { get; set; }
+        private static object onLegacyIpcMessageReceived(object message)
+        {
+            switch (message)
+            {
+                case LegacyIpcDifficultyCalculationRequest req:
+                    try
+                    {
+                        Ruleset ruleset = req.RulesetId switch
+                        {
+                            0 => new OsuRuleset(),
+                            1 => new TaikoRuleset(),
+                            2 => new CatchRuleset(),
+                            3 => new ManiaRuleset(),
+                            _ => throw new ArgumentException("Invalid ruleset id")
+                        };
+
+                        Mod[] mods = ruleset.ConvertFromLegacyMods((LegacyMods)req.Mods).ToArray();
+                        WorkingBeatmap beatmap = new FlatFileWorkingBeatmap(req.BeatmapFile, _ => ruleset);
+
+                        return new LegacyIpcDifficultyCalculationResponse
+                        {
+                            StarRating = ruleset.CreateDifficultyCalculator(beatmap).Calculate(mods).StarRating
+                        };
+                    }
+                    catch
+                    {
+                        return new LegacyIpcDifficultyCalculationResponse();
+                    }
+            }
+
+            Console.WriteLine("Type not matched.");
+            return null;
+        }
     }
 }