feat: Add CancelTrace method to the GasTracer

Author: s2quake

src/Libplanet.Action/ActionEvaluator.cs

@@ -471,13 +471,14 @@ internal IEnumerable<ActionEvaluation> EvaluateTx(
             IWorld previousState)
         {
             GasTracer.Initialize(tx.GasLimit ?? long.MaxValue);
-            GasTracer.StartTrace();
             var evaluations = ImmutableList<ActionEvaluation>.Empty;
             if (_policyActionsRegistry.BeginTxActions.Length > 0)
             {
+                GasTracer.IsTxAction = true;
                 evaluations = evaluations.AddRange(
                     EvaluatePolicyBeginTxActions(block, tx, previousState));
                 previousState = evaluations.Last().OutputState;
+                GasTracer.IsTxAction = false;
             }
 
             ImmutableList<IAction> actions =
@@ -500,7 +501,7 @@ internal IEnumerable<ActionEvaluation> EvaluateTx(
                     EvaluatePolicyEndTxActions(block, tx, previousState));
             }
 
-            GasTracer.EndTrace();
+            GasTracer.Release();
 
             return evaluations;
         }

src/Libplanet.Action/GasMeter.cs

@@ -2,10 +2,14 @@ namespace Libplanet.Action
 {
     internal class GasMeter : IGasMeter
     {
-        public GasMeter(long gasLimit, long gasUsed = 0)
+        public GasMeter(long gasLimit)
         {
-            SetGasLimit(gasLimit);
-            GasUsed = gasUsed;
+            if (gasLimit < 0)
+            {
+                throw new GasLimitNegativeException();
+            }
+
+            GasLimit = gasLimit;
         }
 
         public long GasAvailable => GasLimit - GasUsed;
@@ -39,15 +43,5 @@ public void UseGas(long gas)
 
             GasUsed = newGasUsed;
         }
-
-        private void SetGasLimit(long gasLimit)
-        {
-            if (gasLimit < 0)
-            {
-                throw new GasLimitNegativeException();
-            }
-
-            GasLimit = gasLimit;
-        }
     }
 }

src/Libplanet.Action/GasTracer.cs

@@ -16,6 +16,8 @@ public static class GasTracer
 
         private static readonly AsyncLocal<bool> IsTrace = new AsyncLocal<bool>();
 
+        private static readonly AsyncLocal<bool> IsTraceCancelled = new AsyncLocal<bool>();
+
         /// <summary>
         /// The amount of gas used so far.
         /// </summary>
@@ -26,6 +28,8 @@ public static class GasTracer
         /// </summary>
         public static long GasAvailable => GasMeterValue.GasAvailable;
 
+        internal static bool IsTxAction { get; set; }
+
         private static GasMeter GasMeterValue
             => GasMeter.Value ?? throw new InvalidOperationException(
                 "GasTracer is not initialized.");
@@ -41,23 +45,39 @@ public static void UseGas(long gas)
             if (IsTrace.Value)
             {
                 GasMeterValue.UseGas(gas);
+                if (IsTraceCancelled.Value)
+                {
+                    throw new InvalidOperationException("GasTracing was canceled.");
+                }
             }
         }
 
-        internal static void Initialize(long gasLimit)
+        public static void CancelTrace()
         {
-            GasMeter.Value = new GasMeter(gasLimit);
-            IsTrace.Value = false;
+            if (!IsTxAction)
+            {
+                throw new InvalidOperationException("CancelTrace can only be called in TxAction.");
+            }
+
+            if (IsTraceCancelled.Value)
+            {
+                throw new InvalidOperationException("GasTracing is already canceled.");
+            }
+
+            IsTraceCancelled.Value = true;
         }
 
-        internal static void StartTrace()
+        internal static void Initialize(long gasLimit)
         {
+            GasMeter.Value = new GasMeter(gasLimit);
             IsTrace.Value = true;
+            IsTraceCancelled.Value = false;
         }
 
-        internal static void EndTrace()
+        internal static void Release()
         {
             IsTrace.Value = false;
+            IsTraceCancelled.Value = false;
         }
     }
 }