rewrite multiplayer sync to use generic callbacks from client/server for better extensibility (#480)

4 files changed, 160 insertions, 31 deletions

diff --git a/src/SMAPI/Framework/Networking/MessageType.cs b/src/SMAPI/Framework/Networking/MessageType.cs
new file mode 100644
index 00000000..bd9acfa9
--- /dev/null
+++ b/src/SMAPI/Framework/Networking/MessageType.cs
@@ -0,0 +1,26 @@
+using StardewValley;
+
+namespace StardewModdingAPI.Framework.Networking
+{
+    /// <summary>Network message types recognised by SMAPI and Stardew Valley.</summary>
+    internal enum MessageType : byte
+    {
+        /*********
+        ** SMAPI
+        *********/
+        /// <summary>A data message intended for mods to consume.</summary>
+        ModMessage = 254,
+
+        /// <summary>Metadata context about a player synced by SMAPI.</summary>
+        ModContext = 255,
+
+        /*********
+        ** Vanilla
+        *********/
+        /// <summary>Metadata about the host server sent to a farmhand.</summary>
+        ServerIntroduction = Multiplayer.serverIntroduction,
+
+        /// <summary>Metadata about a player sent to a farmhand or server.</summary>
+        PlayerIntroduction = Multiplayer.playerIntroduction
+    }
+}
diff --git a/src/SMAPI/Framework/Networking/MultiplayerPeer.cs b/src/SMAPI/Framework/Networking/MultiplayerPeer.cs
index c7f8ffad..e703dbb1 100644
--- a/src/SMAPI/Framework/Networking/MultiplayerPeer.cs
+++ b/src/SMAPI/Framework/Networking/MultiplayerPeer.cs
@@ -2,7 +2,6 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using Lidgren.Network;
-using StardewValley;
 using StardewValley.Network;
 
 namespace StardewModdingAPI.Framework.Networking
@@ -95,7 +94,8 @@ namespace StardewModdingAPI.Framework.Networking
         /// <param name="playerID">The player's unique ID.</param>
         /// <param name="model">The metadata to copy.</param>
         /// <param name="client">The client through which to send messages.</param>
-        public static MultiplayerPeer ForConnectionToHost(long playerID, RemoteContextModel model, SLidgrenClient client)
+        /// <param name="isHost">Whether this connection is for the host player.</param>
+        public static MultiplayerPeer ForConnectionToHost(long playerID, RemoteContextModel model, SLidgrenClient client, bool isHost)
         {
             return new MultiplayerPeer(
                 playerID: playerID,
@@ -103,7 +103,7 @@ namespace StardewModdingAPI.Framework.Networking
                 server: null,
                 serverConnection: null,
                 client: client,
-                isHost: true
+                isHost: isHost
             );
         }
 
diff --git a/src/SMAPI/Framework/Networking/SLidgrenClient.cs b/src/SMAPI/Framework/Networking/SLidgrenClient.cs
index 9dfdba15..c05e6b76 100644
--- a/src/SMAPI/Framework/Networking/SLidgrenClient.cs
+++ b/src/SMAPI/Framework/Networking/SLidgrenClient.cs
@@ -1,44 +1,38 @@
 using System;
-using StardewValley;
 using StardewValley.Network;
 
 namespace StardewModdingAPI.Framework.Networking
 {
-    /// <summary>A multiplayer client used to connect to a hosted server. This is an implementation of <see cref="LidgrenClient"/> that adds support for SMAPI's metadata context exchange.</summary>
+    /// <summary>A multiplayer client used to connect to a hosted server. This is an implementation of <see cref="LidgrenClient"/> with callbacks for SMAPI functionality.</summary>
     internal class SLidgrenClient : LidgrenClient
     {
         /*********
         ** Properties
         *********/
-        /// <summary>Get the metadata to include in a metadata message sent to other players.</summary>
-        private readonly Func<object[]> GetMetadataMessageFields;
-
-        /// <summary>The method to call when receiving a custom SMAPI message from the server, which returns whether the message was processed.</summary>
-        private readonly Func<SLidgrenClient, IncomingMessage, bool> TryProcessMessage;
+        /// <summary>A callback to raise when receiving a message. This receives the client instance, incoming message, and a callback to run the default logic.</summary>
+        private readonly Action<SLidgrenClient, IncomingMessage, Action> OnProcessingMessage;
 
+        /// <summary>A callback to raise when sending a message. This receives the client instance, outgoing message, and a callback to run the default logic.</summary>
+        private readonly Action<SLidgrenClient, OutgoingMessage, Action> OnSendingMessage;
 
         /*********
         ** Public methods
         *********/
         /// <summary>Construct an instance.</summary>
         /// <param name="address">The remote address being connected.</param>
-        /// <param name="getMetadataMessageFields">Get the metadata to include in a metadata message sent to other players.</param>
-        /// <param name="tryProcessMessage">The method to call when receiving a custom SMAPI message from the server, which returns whether the message was processed..</param>
-        public SLidgrenClient(string address, Func<object[]> getMetadataMessageFields, Func<SLidgrenClient, IncomingMessage, bool> tryProcessMessage)
+        /// <param name="onProcessingMessage">A callback to raise when receiving a message. This receives the client instance, incoming message, and a callback to run the default logic.</param>
+        /// <param name="onSendingMessage">A callback to raise when sending a message. This receives the client instance, outgoing message, and a callback to run the default logic.</param>
+        public SLidgrenClient(string address, Action<SLidgrenClient, IncomingMessage, Action> onProcessingMessage, Action<SLidgrenClient, OutgoingMessage, Action> onSendingMessage)
             : base(address)
         {
-            this.GetMetadataMessageFields = getMetadataMessageFields;
-            this.TryProcessMessage = tryProcessMessage;
+            this.OnProcessingMessage = onProcessingMessage;
+            this.OnSendingMessage = onSendingMessage;
         }
 
-        /// <summary>Send the metadata needed to connect with a remote server.</summary>
-        public override void sendPlayerIntroduction()
+        /// <summary>Send a message to the connected peer.</summary>
+        public override void sendMessage(OutgoingMessage message)
         {
-            // send custom intro
-            if (this.getUserID() != "")
-                Game1.player.userID.Value = this.getUserID();
-            this.sendMessage(SMultiplayer.ContextSyncMessageID, this.GetMetadataMessageFields());
-            base.sendPlayerIntroduction();
+            this.OnSendingMessage(this, message, () => base.sendMessage(message));
         }
 
 
@@ -49,10 +43,7 @@ namespace StardewModdingAPI.Framework.Networking
         /// <param name="message">The message to process.</param>
         protected override void processIncomingMessage(IncomingMessage message)
         {
-            if (this.TryProcessMessage(this, message))
-                return;
-
-            base.processIncomingMessage(message);
+            this.OnProcessingMessage(this, message, () => base.processIncomingMessage(message));
         }
     }
 }
diff --git a/src/SMAPI/Framework/Networking/SLidgrenServer.cs b/src/SMAPI/Framework/Networking/SLidgrenServer.cs
index 971eb66d..060b433b 100644
--- a/src/SMAPI/Framework/Networking/SLidgrenServer.cs
+++ b/src/SMAPI/Framework/Networking/SLidgrenServer.cs
@@ -1,5 +1,11 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+using System.IO;
 using System.Reflection;
 using Lidgren.Network;
+using StardewModdingAPI.Framework.Reflection;
+using StardewModdingAPI.Patches;
+using StardewValley;
 using StardewValley.Network;
 
 namespace StardewModdingAPI.Framework.Networking
@@ -10,8 +16,27 @@ namespace StardewModdingAPI.Framework.Networking
         /*********
         ** Properties
         *********/
-        /// <summary>A method which sends a message through a specific connection.</summary>
-        private readonly MethodInfo SendMessageToConnectionMethod;
+
+        /// <summary>The constructor for the internal <c>NetBufferReadStream</c> type.</summary>
+        private readonly ConstructorInfo NetBufferReadStreamConstructor = SLidgrenServer.GetNetBufferReadStreamConstructor();
+
+        /// <summary>The constructor for the internal <c>NetBufferWriteStream</c> type.</summary>
+        private readonly ConstructorInfo NetBufferWriteStreamConstructor = SLidgrenServer.GetNetBufferWriteStreamConstructor();
+
+        /// <summary>A method which reads farmer data from the given binary reader.</summary>
+        private readonly Func<BinaryReader, NetFarmerRoot> ReadFarmer;
+
+        /// <summary>A callback to raise when receiving a message. This receives the server instance, raw/parsed incoming message, and a callback to run the default logic.</summary>
+        private readonly Action<SLidgrenServer, NetIncomingMessage, IncomingMessage, Action> OnProcessingMessage;
+
+        /// <summary>A callback to raise when sending a message. This receives the server instance, outgoing connection, outgoing message, target player ID, and a callback to run the default logic.</summary>
+        private readonly Action<SLidgrenServer, NetConnection, OutgoingMessage, Action> OnSendingMessage;
+
+        /// <summary>The peer connections.</summary>
+        private readonly Bimap<long, NetConnection> Peers;
+
+        /// <summary>The underlying net server.</summary>
+        private readonly IReflectedField<NetServer> Server;
 
 
         /*********
@@ -19,18 +44,105 @@ namespace StardewModdingAPI.Framework.Networking
         *********/
         /// <summary>Construct an instance.</summary>
         /// <param name="gameServer">The underlying game server.</param>
-        public SLidgrenServer(IGameServer gameServer)
+        /// <param name="reflection">Simplifies access to private code.</param>
+        /// <param name="readFarmer">A method which reads farmer data from the given binary reader.</param>
+        /// <param name="onProcessingMessage">A callback to raise when receiving a message. This receives the server instance, raw/parsed incoming message, and a callback to run the default logic.</param>
+        /// <param name="onSendingMessage">A callback to raise when sending a message. This receives the server instance, outgoing connection, outgoing message, and a callback to run the default logic.</param>
+        public SLidgrenServer(IGameServer gameServer, Reflector reflection, Func<BinaryReader, NetFarmerRoot> readFarmer, Action<SLidgrenServer, NetIncomingMessage, IncomingMessage, Action> onProcessingMessage, Action<SLidgrenServer, NetConnection, OutgoingMessage, Action> onSendingMessage)
             : base(gameServer)
         {
-            this.SendMessageToConnectionMethod = typeof(LidgrenServer).GetMethod(nameof(LidgrenServer.sendMessage), BindingFlags.NonPublic | BindingFlags.Instance, null, new[] { typeof(NetConnection), typeof(OutgoingMessage) }, null);
+            this.ReadFarmer = readFarmer;
+            this.OnProcessingMessage = onProcessingMessage;
+            this.OnSendingMessage = onSendingMessage;
+            this.Peers = reflection.GetField<Bimap<long, NetConnection>>(this, "peers").GetValue();
+            this.Server = reflection.GetField<NetServer>(this, "server");
         }
 
         /// <summary>Send a message to a remote server.</summary>
         /// <param name="connection">The network connection.</param>
         /// <param name="message">The message to send.</param>
+        /// <remarks>This is an implementation of <see cref="LidgrenServer.sendMessage(NetConnection, OutgoingMessage)"/> which calls <see cref="OnSendingMessage"/>. This method is invoked via <see cref="LidgrenServerPatch.Prefix_LidgrenServer_SendMessage"/>.</remarks>
         public void SendMessage(NetConnection connection, OutgoingMessage message)
         {
-            this.SendMessageToConnectionMethod.Invoke(this, new object[] { connection, message });
+            this.OnSendingMessage(this, connection, message, () =>
+            {
+                NetServer server = this.Server.GetValue();
+                NetOutgoingMessage netMessage = server.CreateMessage();
+                using (Stream bufferWriteStream = (Stream)this.NetBufferWriteStreamConstructor.Invoke(new object[] { netMessage }))
+                using (BinaryWriter writer = new BinaryWriter(bufferWriteStream))
+                    message.Write(writer);
+
+                server.SendMessage(netMessage, connection, NetDeliveryMethod.ReliableOrdered);
+            });
+        }
+
+        /// <summary>Parse a data message from a client.</summary>
+        /// <param name="rawMessage">The raw network message to parse.</param>
+        /// <remarks>This is an implementation of <see cref="LidgrenServer.parseDataMessageFromClient"/> which calls <see cref="OnProcessingMessage"/>. This method is invoked via <see cref="LidgrenServerPatch.Prefix_LidgrenServer_ParseDataMessageFromClient"/>.</remarks>
+        [SuppressMessage("ReSharper", "AccessToDisposedClosure", Justification = "The callback is invoked synchronously.")]
+        public bool ParseDataMessageFromClient(NetIncomingMessage rawMessage)
+        {
+            // add hook to call multiplayer core
+            NetConnection peer = rawMessage.SenderConnection;
+            using (IncomingMessage message = new IncomingMessage())
+            using (Stream readStream = (Stream)this.NetBufferReadStreamConstructor.Invoke(new object[] { rawMessage }))
+            using (BinaryReader reader = new BinaryReader(readStream))
+            {
+                while (rawMessage.LengthBits - rawMessage.Position >= 8)
+                {
+                    message.Read(reader);
+                    this.OnProcessingMessage(this, rawMessage, message, () =>
+                    {
+                        if (this.Peers.ContainsLeft(message.FarmerID) && this.Peers[message.FarmerID] == peer)
+                            this.gameServer.processIncomingMessage(message);
+                        else if (message.MessageType == Multiplayer.playerIntroduction)
+                        {
+                            NetFarmerRoot farmer = this.ReadFarmer(message.Reader);
+                            this.gameServer.checkFarmhandRequest("", farmer, msg => this.SendMessage(peer, msg), () => this.Peers[farmer.Value.UniqueMultiplayerID] = peer);
+                        }
+                    });
+                }
+            }
+
+            return false;
+        }
+
+
+        /*********
+        ** Private methods
+        *********/
+        /// <summary>Get the constructor for the internal <c>NetBufferReadStream</c> type.</summary>
+        private static ConstructorInfo GetNetBufferReadStreamConstructor()
+        {
+            // get type
+            string typeName = $"StardewValley.Network.NetBufferReadStream, {Constants.GameAssemblyName}";
+            Type type = Type.GetType(typeName);
+            if (type == null)
+                throw new InvalidOperationException($"Can't find type: {typeName}");
+
+            // get constructor
+            ConstructorInfo constructor = type.GetConstructor(new[] { typeof(NetBuffer) });
+            if (constructor == null)
+                throw new InvalidOperationException($"Can't find constructor for type: {typeName}");
+
+            return constructor;
+        }
+
+        /// <summary>Get the constructor for the internal <c>NetBufferWriteStream</c> type.</summary>
+        private static ConstructorInfo GetNetBufferWriteStreamConstructor()
+        {
+            // get type
+            string typeName = $"StardewValley.Network.NetBufferWriteStream, {Constants.GameAssemblyName}";
+            Type type = Type.GetType(typeName);
+            if (type == null)
+                throw new InvalidOperationException($"Can't find type: {typeName}");
+
+            // get constructor
+            ConstructorInfo constructor = type.GetConstructor(new[] { typeof(NetBuffer) });
+            if (constructor == null)
+                throw new InvalidOperationException($"Can't find constructor for type: {typeName}");
+
+            return constructor;
         }
     }
 }