From eb44a5c44aa43a383ef671c8b82759c14a92900e Mon Sep 17 00:00:00 2001
From: Susko3 <16479013+Susko3@users.noreply.github.com>
Date: Fri, 17 Dec 2021 13:02:42 +0100
Subject: [PATCH] Add code path for handling window messages

Some IME messages didn't get sent trough `SDL_SetWindowsMessageHook`, so this alternative is required.
---
 osu.Framework/Platform/SDL2/SDL2Extensions.cs | 31 +++++++++++++++++++
 osu.Framework/Platform/SDL2DesktopWindow.cs   | 17 ++++++++++
 2 files changed, 48 insertions(+)

diff --git a/osu.Framework/Platform/SDL2/SDL2Extensions.cs b/osu.Framework/Platform/SDL2/SDL2Extensions.cs
index d7aef492b5..e40ec4bdf1 100644
--- a/osu.Framework/Platform/SDL2/SDL2Extensions.cs
+++ b/osu.Framework/Platform/SDL2/SDL2Extensions.cs
@@ -1011,5 +1011,36 @@ public static unsafe bool TryGetStringFromBytePointer(byte* bytePointer, out str
             str = Marshal.PtrToStringUTF8(ptr) ?? string.Empty;
             return true;
         }
+
+        // ReSharper disable InconsistentNaming (mimics SDL and SDL2-CS naming)
+        // ReSharper disable IdentifierTypo
+
+        [StructLayout(LayoutKind.Sequential)]
+        internal struct INTERNAL_windows_wmmsg
+        {
+            public IntPtr hwnd;
+            public uint msg;
+            public ulong wParam;
+            public long lParam;
+        }
+
+        [StructLayout(LayoutKind.Explicit)]
+        internal struct INTERNAL_SysWMmsgUnion
+        {
+            [FieldOffset(0)]
+            public INTERNAL_windows_wmmsg win;
+            // could add more native events here if required
+        }
+
+        [StructLayout(LayoutKind.Sequential)]
+        internal struct SDL_SysWMmsg
+        {
+            public SDL.SDL_version version;
+            public SDL.SDL_SYSWM_TYPE subsystem;
+            public INTERNAL_SysWMmsgUnion msg;
+        }
+
+        // ReSharper restore InconsistentNaming
+        // ReSharper restore IdentifierTypo
     }
 }
diff --git a/osu.Framework/Platform/SDL2DesktopWindow.cs b/osu.Framework/Platform/SDL2DesktopWindow.cs
index cb2cd73585..c9d9857889 100644
--- a/osu.Framework/Platform/SDL2DesktopWindow.cs
+++ b/osu.Framework/Platform/SDL2DesktopWindow.cs
@@ -718,6 +718,10 @@ private void handleSDLEvent(SDL.SDL_Event e)
                 case SDL.SDL_EventType.SDL_DROPCOMPLETE:
                     handleDropEvent(e.drop);
                     break;
+
+                case SDL.SDL_EventType.SDL_SYSWMEVENT:
+                    HandleSysWMEvent(e.syswm);
+                    break;
             }
         }
 
@@ -986,6 +990,19 @@ private void handleWindowEvent(SDL.SDL_WindowEvent evtWindow)
             }
         }
 
+        /// <summary>
+        /// Override if platform requires special handling of native events.
+        /// </summary>
+        /// <remarks>
+        /// Make sure to enable the events with
+        ///   <code>
+        ///     SDL.SDL_EventState(SDL.SDL_EventType.SDL_SYSWMEVENT, SDL.SDL_ENABLE);
+        ///   </code>
+        /// </remarks>
+        protected virtual void HandleSysWMEvent(SDL.SDL_SysWMEvent sysWM)
+        {
+        }
+
         /// <summary>
         /// Should be run on a regular basis to check for external window state changes.
         /// </summary>