Unity il2cpp support (discord#249)

* Initial il2cpp support attempts

* Fix crashes

* Different variable name

* Fix indenting

* Change back unneeded stuff
- callbackCalls didnt seem to do anything

Author: msciotti

examples/button-clicker/Assets/DiscordController.cs

@@ -14,7 +14,6 @@ public class DiscordController : MonoBehaviour
     public DiscordRpc.RichPresence presence = new DiscordRpc.RichPresence();
     public string applicationId;
     public string optionalSteamId;
-    public int callbackCalls;
     public int clickCounter;
     public DiscordRpc.DiscordUser joinRequest;
     public UnityEngine.Events.UnityEvent onConnect;
@@ -52,41 +51,35 @@ public void RequestRespondNo()
 
     public void ReadyCallback(ref DiscordRpc.DiscordUser connectedUser)
     {
-        ++callbackCalls;
         Debug.Log(string.Format("Discord: connected to {0}#{1}: {2}", connectedUser.username, connectedUser.discriminator, connectedUser.userId));
         onConnect.Invoke();
     }
 
     public void DisconnectedCallback(int errorCode, string message)
     {
-        ++callbackCalls;
         Debug.Log(string.Format("Discord: disconnect {0}: {1}", errorCode, message));
         onDisconnect.Invoke();
     }
 
     public void ErrorCallback(int errorCode, string message)
     {
-        ++callbackCalls;
         Debug.Log(string.Format("Discord: error {0}: {1}", errorCode, message));
     }
 
     public void JoinCallback(string secret)
     {
-        ++callbackCalls;
         Debug.Log(string.Format("Discord: join ({0})", secret));
         onJoin.Invoke(secret);
     }
 
     public void SpectateCallback(string secret)
     {
-        ++callbackCalls;
         Debug.Log(string.Format("Discord: spectate ({0})", secret));
         onSpectate.Invoke(secret);
     }
 
     public void RequestCallback(ref DiscordRpc.DiscordUser request)
     {
-        ++callbackCalls;
         Debug.Log(string.Format("Discord: join request {0}#{1}: {2}", request.username, request.discriminator, request.userId));
         joinRequest = request;
         onJoinRequest.Invoke(request);
@@ -104,10 +97,8 @@ void Update()
     void OnEnable()
     {
         Debug.Log("Discord: init");
-        callbackCalls = 0;
-
         handlers = new DiscordRpc.EventHandlers();
-        handlers.readyCallback = ReadyCallback;
+        handlers.readyCallback += ReadyCallback;
         handlers.disconnectedCallback += DisconnectedCallback;
         handlers.errorCallback += ErrorCallback;
         handlers.joinCallback += JoinCallback;

examples/button-clicker/Assets/DiscordRpc.cs

@@ -2,35 +2,42 @@
 using System.Collections.Generic;
 using System.Runtime.InteropServices;
 using System.Text;
+using AOT;
 
 public class DiscordRpc
 {
-    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
-    public delegate void ReadyCallback(ref DiscordUser connectedUser);
+    [MonoPInvokeCallback(typeof(OnReadyInfo))]
+    public static void ReadyCallback(ref DiscordUser connectedUser) { }
+    public delegate void OnReadyInfo(ref DiscordUser connectedUser);
 
-    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
-    public delegate void DisconnectedCallback(int errorCode, string message);
+    [MonoPInvokeCallback(typeof(OnDisconnectedInfo))]
+    public static void DisconnectedCallback(int errorCode, string message) { }
+    public delegate void OnDisconnectedInfo(int errorCode, string message);
 
-    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
-    public delegate void ErrorCallback(int errorCode, string message);
+    [MonoPInvokeCallback(typeof(OnErrorInfo))]
+    public static void ErrorCallback(int errorCode, string message) { }
+    public delegate void OnErrorInfo(int errorCode, string message);
 
-    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
-    public delegate void JoinCallback(string secret);
+    [MonoPInvokeCallback(typeof(OnJoinInfo))]
+    public static void JoinCallback(string secret) { }
+    public delegate void OnJoinInfo(string secret);
 
-    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
-    public delegate void SpectateCallback(string secret);
+    [MonoPInvokeCallback(typeof(OnSpectateInfo))]
+    public static void SpectateCallback(string secret) { }
+    public delegate void OnSpectateInfo(string secret);
 
-    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
-    public delegate void RequestCallback(ref DiscordUser request);
+    [MonoPInvokeCallback(typeof(OnRequestInfo))]
+    public static void RequestCallback(ref DiscordUser request) { }
+    public delegate void OnRequestInfo(ref DiscordUser request);
 
     public struct EventHandlers
     {
-        public ReadyCallback readyCallback;
-        public DisconnectedCallback disconnectedCallback;
-        public ErrorCallback errorCallback;
-        public JoinCallback joinCallback;
-        public SpectateCallback spectateCallback;
-        public RequestCallback requestCallback;
+        public OnReadyInfo readyCallback;
+        public OnDisconnectedInfo disconnectedCallback;
+        public OnErrorInfo errorCallback;
+        public OnJoinInfo joinCallback;
+        public OnSpectateInfo spectateCallback;
+        public OnRequestInfo requestCallback;
     }
 
     [Serializable, StructLayout(LayoutKind.Sequential)]
@@ -160,7 +167,7 @@ private IntPtr StrToPtr(string input)
             var buffer = Marshal.AllocHGlobal(convbytecnt + 1);
             for (int i = 0; i < convbytecnt + 1; i++)
             {
-                Marshal.WriteByte(buffer, i , 0);
+                Marshal.WriteByte(buffer, i, 0);
             }
             _buffers.Add(buffer);
             Marshal.Copy(Encoding.UTF8.GetBytes(input), 0, buffer, convbytecnt);