1 files changed, 128 insertions, 0 deletions
diff --git a/src/Ryujinx.Graphics.Gpu/Synchronization/Syncpoint.cs b/src/Ryujinx.Graphics.Gpu/Synchronization/Syncpoint.cs
new file mode 100644
index 00000000..39fb83c0
--- /dev/null
+++ b/src/Ryujinx.Graphics.Gpu/Synchronization/Syncpoint.cs
@@ -0,0 +1,128 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+
+namespace Ryujinx.Graphics.Gpu.Synchronization
+{
+    /// <summary>
+    /// Represents GPU hardware syncpoint.
+    /// </summary>
+    class Syncpoint
+    {
+        private int _storedValue;
+
+        public readonly uint Id;
+
+        /// <summary>
+        /// The value of the syncpoint.
+        /// </summary>
+        public uint Value => (uint)_storedValue;
+
+        // TODO: switch to something handling concurrency?
+        private readonly List<SyncpointWaiterHandle> _waiters;
+
+        public Syncpoint(uint id)
+        {
+            Id       = id;
+            _waiters = new List<SyncpointWaiterHandle>();
+        }
+
+        /// <summary>
+        /// Register a new callback for a target threshold.
+        /// The callback will be called once the threshold is reached and will automatically be unregistered.
+        /// </summary>
+        /// <param name="threshold">The target threshold</param>
+        /// <param name="callback">The callback to call when the threshold is reached</param>
+        /// <returns>The created SyncpointWaiterHandle object or null if already past threshold</returns>
+        public SyncpointWaiterHandle RegisterCallback(uint threshold, Action<SyncpointWaiterHandle> callback)
+        {
+            lock (_waiters)
+            {
+                if (Value >= threshold)
+                {
+                    callback(null);
+
+                    return null;
+                }
+                else
+                {
+                    SyncpointWaiterHandle waiterInformation = new SyncpointWaiterHandle
+                    {
+                        Threshold = threshold,
+                        Callback  = callback
+                    };
+
+                    _waiters.Add(waiterInformation);
+
+                    return waiterInformation;
+                }
+            }
+        }
+
+        public void UnregisterCallback(SyncpointWaiterHandle waiterInformation)
+        {
+            lock (_waiters)
+            {
+                _waiters.Remove(waiterInformation);
+            }
+        }
+
+        /// <summary>
+        /// Increment the syncpoint
+        /// </summary>
+        /// <returns>The incremented value of the syncpoint</returns>
+        public uint Increment()
+        {
+            uint currentValue = (uint)Interlocked.Increment(ref _storedValue);
+
+            SyncpointWaiterHandle expired = null;
+            List<SyncpointWaiterHandle> expiredList = null;
+
+            lock (_waiters)
+            {
+                _waiters.RemoveAll(item =>
+                {
+                    bool isPastThreshold = currentValue >= item.Threshold;
+
+                    if (isPastThreshold)
+                    {
+                        if (expired == null)
+                        {
+                            expired = item;
+                        }
+                        else
+                        {
+                            if (expiredList == null)
+                            {
+                                expiredList = new List<SyncpointWaiterHandle>();
+                            }
+
+                            expiredList.Add(item);
+                        }
+                    }
+
+                    return isPastThreshold;
+                });
+            }
+
+            // Call the callbacks as a separate step.
+            // As we don't know what the callback will be doing,
+            // and it could block execution for a indefinite amount of time,
+            // we can't call it inside the lock.
+            if (expired != null)
+            {
+                expired.Callback(expired);
+
+                if (expiredList != null)
+                {
+                    for (int i = 0; i < expiredList.Count; i++)
+                    {
+                        expiredList[i].Callback(expiredList[i]);
+                    }
+                }
+            }
+
+            return currentValue;
+        }
+    }
+}