fix pre-action crash (ryubing/ryujinx!236)

See merge request ryubing/ryujinx!236

src/Ryujinx.Graphics.Gpu/GpuContext.cs

@@ -404,9 +404,12 @@ namespace Ryujinx.Graphics.Gpu
 
             if (force || _pendingSync || (syncPoint && SyncpointActions.Count > 0))
             {
-                foreach (ISyncActionHandler action in SyncActions)
+                for (int i = 0; i < SyncActions.Count; i++)
                 {
-                    action.SyncPreAction(syncPoint);
+                    if (SyncActions[i].SyncPreAction(syncPoint))
+                    {
+                        SyncActions.RemoveAt(i--);
+                    }
                 }
 
                 foreach (ISyncActionHandler action in SyncpointActions)

src/Ryujinx.Graphics.Gpu/Image/TextureGroupHandle.cs

@@ -411,7 +411,7 @@ namespace Ryujinx.Graphics.Gpu.Image
         /// flushes often enough, which is determined by the flush balance.
         /// </summary>
         /// <inheritdoc/>
-        public void SyncPreAction(bool syncpoint)
+        public bool SyncPreAction(bool syncpoint)
         {
             if (syncpoint || NextSyncCopies())
             {
@@ -421,6 +421,8 @@ namespace Ryujinx.Graphics.Gpu.Image
                     _registeredBufferSync = _modifiedSync;
                 }
             }
+
+            return true;
         }
 
         /// <summary>

src/Ryujinx.Graphics.Gpu/Memory/Buffer.cs

@@ -393,11 +393,16 @@ namespace Ryujinx.Graphics.Gpu.Memory
         /// This will copy any buffer ranges designated for pre-flushing.
         /// </summary>
         /// <param name="syncpoint">True if the action is a guest syncpoint</param>
-        public void SyncPreAction(bool syncpoint)
+        public bool SyncPreAction(bool syncpoint)
         {
+            if (_bufferInherited)
+            {
+                return true;
+            }
+            
             if (_referenceCount == 0)
             {
-                return;
+                return false;
             }
 
             if (BackingState.ShouldChangeBacking())
@@ -414,6 +419,8 @@ namespace Ryujinx.Graphics.Gpu.Memory
                     _modifiedRanges?.GetRangesAtSync(Address, Size, _context.SyncNumber, _syncPreRangeAction);
                 }
             }
+
+            return false;
         }
         
         void SyncPreRangeAction(ulong address, ulong size)

src/Ryujinx.Graphics.Gpu/Synchronization/ISyncActionHandler.cs

@@ -17,6 +17,6 @@ namespace Ryujinx.Graphics.Gpu.Synchronization
         /// Action to be performed immediately before sync is created.
         /// </summary>
         /// <param name="syncpoint">True if the action is a guest syncpoint</param>
-        void SyncPreAction(bool syncpoint) { }
+        bool SyncPreAction(bool syncpoint) { return true; }
     }
 }