sync SMAPI context between players in multiplayer (#480)

1 files changed, 103 insertions, 0 deletions

diff --git a/src/SMAPI/Patches/NetworkingPatch.cs b/src/SMAPI/Patches/NetworkingPatch.cs
new file mode 100644
index 00000000..12ccf84c
--- /dev/null
+++ b/src/SMAPI/Patches/NetworkingPatch.cs
@@ -0,0 +1,103 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+using System.IO;
+using System.Reflection;
+using Harmony;
+using Lidgren.Network;
+using StardewModdingAPI.Framework;
+using StardewModdingAPI.Framework.Networking;
+using StardewModdingAPI.Framework.Patching;
+using StardewValley;
+using StardewValley.Network;
+
+namespace StardewModdingAPI.Patches
+{
+    /// <summary>A Harmony patch to enable the SMAPI multiplayer metadata handshake.</summary>
+    internal class NetworkingPatch : IHarmonyPatch
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>The constructor for the internal <c>NetBufferReadStream</c> type.</summary>
+        private static readonly ConstructorInfo NetBufferReadStreamConstructor = NetworkingPatch.GetNetBufferReadStreamConstructor();
+
+
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>A unique name for this patch.</summary>
+        public string Name => $"{nameof(NetworkingPatch)}";
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Apply the Harmony patch.</summary>
+        /// <param name="harmony">The Harmony instance.</param>
+        public void Apply(HarmonyInstance harmony)
+        {
+            MethodInfo method = AccessTools.Method(typeof(LidgrenServer), "parseDataMessageFromClient");
+            MethodInfo prefix = AccessTools.Method(this.GetType(), nameof(NetworkingPatch.Prefix_LidgrenServer_ParseDataMessageFromClient));
+            harmony.Patch(method, new HarmonyMethod(prefix), null);
+        }
+
+
+        /*********
+        ** Private methods
+        *********/
+        /// <summary>The method to call instead of the <see cref="LidgrenServer.parseDataMessageFromClient"/> method.</summary>
+        /// <param name="__instance">The instance being patched.</param>
+        /// <param name="dataMsg">The raw network message to parse.</param>
+        /// <param name="___peers">The private <c>peers</c> field on the <paramref name="__instance"/> instance.</param>
+        /// <param name="___gameServer">The private <c>gameServer</c> field on the <paramref name="__instance"/> instance.</param>
+        /// <returns>Returns whether to execute the original method.</returns>
+        /// <remarks>This method must be static for Harmony to work correctly. See the Harmony documentation before renaming arguments.</remarks>
+        [SuppressMessage("ReSharper", "InconsistentNaming", Justification = "Argument names are defined by Harmony.")]
+        private static bool Prefix_LidgrenServer_ParseDataMessageFromClient(LidgrenServer __instance, NetIncomingMessage dataMsg, Bimap<long, NetConnection> ___peers, IGameServer ___gameServer)
+        {
+            // get SMAPI overrides
+            SMultiplayer multiplayer = ((SGame)Game1.game1).Multiplayer;
+            SLidgrenServer server = (SLidgrenServer)__instance;
+
+            // add hook to call multiplayer core
+            NetConnection peer = dataMsg.SenderConnection;
+            using (IncomingMessage message = new IncomingMessage())
+            using (Stream readStream = (Stream)NetworkingPatch.NetBufferReadStreamConstructor.Invoke(new object[] { dataMsg }))
+            using (BinaryReader reader = new BinaryReader(readStream))
+            {
+                while (dataMsg.LengthBits - dataMsg.Position >= 8)
+                {
+                    message.Read(reader);
+                    if (___peers.ContainsLeft(message.FarmerID) && ___peers[message.FarmerID] == peer)
+                        ___gameServer.processIncomingMessage(message);
+                    else if (message.MessageType == Multiplayer.playerIntroduction)
+                    {
+                        NetFarmerRoot farmer = multiplayer.readFarmer(message.Reader);
+                        ___gameServer.checkFarmhandRequest("", farmer, msg => server.SendMessage(peer, msg), () => ___peers[farmer.Value.UniqueMultiplayerID] = peer);
+                    }
+                    else
+                        multiplayer.ProcessMessageFromUnknownFarmhand(__instance, dataMsg, message); // added hook
+                }
+            }
+
+            return false;
+        }
+
+        /// <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;
+        }
+    }
+}