Adjust the Charge for Storage Writting

src/neo/SmartContract/ApplicationEngine.cs

@@ -25,6 +25,7 @@ public partial class ApplicationEngine : ExecutionEngine
         public IVerifiable ScriptContainer { get; }
         public StoreView Snapshot { get; }
         public long GasConsumed { get; private set; } = 0;
+
         public UInt160 CurrentScriptHash => CurrentContext?.GetState<ExecutionContextState>().ScriptHash;
         public UInt160 CallingScriptHash => CurrentContext?.GetState<ExecutionContextState>().CallingScriptHash;
         public UInt160 EntryScriptHash => EntryContext?.GetState<ExecutionContextState>().ScriptHash;
@@ -78,7 +79,7 @@ public override void Dispose()
 
         protected override bool OnSysCall(uint method)
         {
-            if (!AddGas(InteropService.GetPrice(method, CurrentContext.EvaluationStack)))
+            if (!AddGas(InteropService.GetPrice(method, CurrentContext.EvaluationStack, Snapshot)))
                 return false;
             return InteropService.Invoke(this, method);
         }

src/neo/SmartContract/InteropDescriptor.cs

@@ -1,3 +1,4 @@
+using Neo.Persistence;
 using Neo.VM;
 using System;
 
@@ -9,7 +10,7 @@ public class InteropDescriptor
         public uint Hash { get; }
         internal Func<ApplicationEngine, bool> Handler { get; }
         public long Price { get; }
-        public Func<EvaluationStack, long> PriceCalculator { get; }
+        public Func<EvaluationStack, StoreView, long> PriceCalculator { get; }
         public TriggerType AllowedTriggers { get; }
         public CallFlags RequiredCallFlags { get; }
 
@@ -19,7 +20,7 @@ internal InteropDescriptor(string method, Func<ApplicationEngine, bool> handler,
             this.Price = price;
         }
 
-        internal InteropDescriptor(string method, Func<ApplicationEngine, bool> handler, Func<EvaluationStack, long> priceCalculator, TriggerType allowedTriggers, CallFlags requiredCallFlags)
+        internal InteropDescriptor(string method, Func<ApplicationEngine, bool> handler, Func<EvaluationStack, StoreView, long> priceCalculator, TriggerType allowedTriggers, CallFlags requiredCallFlags)
             : this(method, handler, allowedTriggers, requiredCallFlags)
         {
             this.PriceCalculator = priceCalculator;
@@ -34,9 +35,9 @@ private InteropDescriptor(string method, Func<ApplicationEngine, bool> handler,
             this.RequiredCallFlags = requiredCallFlags;
         }
 
-        public long GetPrice(EvaluationStack stack)
+        public long GetPrice(EvaluationStack stack, StoreView snapshot)
         {
-            return PriceCalculator is null ? Price : PriceCalculator(stack);
+            return PriceCalculator is null ? Price : PriceCalculator(stack, snapshot);
         }
 
         public static implicit operator uint(InteropDescriptor descriptor)

src/neo/SmartContract/InteropService.Contract.cs

@@ -1,5 +1,6 @@
 using Neo.IO;
 using Neo.Ledger;
+using Neo.Persistence;
 using Neo.SmartContract.Manifest;
 using Neo.VM;
 using Neo.VM.Types;
@@ -19,7 +20,7 @@ public static class Contract
             public static readonly InteropDescriptor CallEx = Register("System.Contract.CallEx", Contract_CallEx, 0_01000000, TriggerType.System | TriggerType.Application, CallFlags.AllowCall);
             public static readonly InteropDescriptor IsStandard = Register("System.Contract.IsStandard", Contract_IsStandard, 0_00030000, TriggerType.All, CallFlags.None);
 
-            private static long GetDeploymentPrice(EvaluationStack stack)
+            private static long GetDeploymentPrice(EvaluationStack stack, StoreView snapshot)
             {
                 int size = stack.Peek(0).GetByteLength() + stack.Peek(1).GetByteLength();
                 return Storage.GasPerByte * size;

src/neo/SmartContract/InteropService.Crypto.cs

@@ -1,6 +1,7 @@
 using Neo.Cryptography;
 using Neo.Network.P2P;
 using Neo.Network.P2P.Payloads;
+using Neo.Persistence;
 using Neo.VM;
 using Neo.VM.Types;
 using System;
@@ -16,7 +17,7 @@ public static class Crypto
             public static readonly InteropDescriptor ECDsaVerify = Register("Neo.Crypto.ECDsaVerify", Crypto_ECDsaVerify, 0_01000000, TriggerType.All, CallFlags.None);
             public static readonly InteropDescriptor ECDsaCheckMultiSig = Register("Neo.Crypto.ECDsaCheckMultiSig", Crypto_ECDsaCheckMultiSig, GetECDsaCheckMultiSigPrice, TriggerType.All, CallFlags.None);
 
-            private static long GetECDsaCheckMultiSigPrice(EvaluationStack stack)
+            private static long GetECDsaCheckMultiSigPrice(EvaluationStack stack, StoreView snapshot)
             {
                 if (stack.Count < 2) return 0;
                 var item = stack.Peek(1);

src/neo/SmartContract/InteropService.Storage.cs

@@ -1,4 +1,5 @@
 using Neo.Ledger;
+using Neo.Persistence;
 using Neo.SmartContract.Iterators;
 using Neo.VM;
 using Neo.VM.Types;
@@ -22,11 +23,30 @@ public static class Storage
             public static readonly InteropDescriptor Find = Register("System.Storage.Find", Storage_Find, 0_01000000, TriggerType.Application, CallFlags.None);
             public static readonly InteropDescriptor Put = Register("System.Storage.Put", Storage_Put, GetStoragePrice, TriggerType.Application, CallFlags.AllowModifyStates);
             public static readonly InteropDescriptor PutEx = Register("System.Storage.PutEx", Storage_PutEx, GetStoragePrice, TriggerType.Application, CallFlags.AllowModifyStates);
-            public static readonly InteropDescriptor Delete = Register("System.Storage.Delete", Storage_Delete, 0_01000000, TriggerType.Application, CallFlags.AllowModifyStates);
+            public static readonly InteropDescriptor Delete = Register("System.Storage.Delete", Storage_Delete, 1 * GasPerByte, TriggerType.Application, CallFlags.AllowModifyStates);
 
-            private static long GetStoragePrice(EvaluationStack stack)
+            private static long GetStoragePrice(EvaluationStack stack, StoreView snapshot)
             {
-                return (stack.Peek(1).GetByteLength() + stack.Peek(2).GetByteLength()) * GasPerByte;
+                var key = stack.Peek(1);
+                var value = stack.Peek(2);
+                var newDataSize = value.IsNull ? 0 : value.GetByteLength();
+                if (!(stack.Peek() is InteropInterface _interface))
+                    throw new InvalidOperationException();
+
+                StorageContext context = _interface.GetInterface<StorageContext>();
+                StorageKey skey = new StorageKey
+                {
+                    Id = context.Id,
+                    Key = key.GetSpan().ToArray()
+                };
+                var skeyValue = snapshot.Storages.TryGet(skey);
+                if (skeyValue is null)
+                    newDataSize += key.GetByteLength();
+                else if (newDataSize <= skeyValue.Value.Length)
+                    newDataSize = 1;
+                else
+                    newDataSize -= skeyValue.Value.Length;
+                return newDataSize * GasPerByte;
             }
 
             private static bool PutExInternal(ApplicationEngine engine, StorageContext context, byte[] key, byte[] value, StorageFlags flags)

src/neo/SmartContract/InteropService.cs

@@ -1,3 +1,4 @@
+using Neo.Persistence;
 using Neo.VM;
 using System;
 using System.Collections.Generic;
@@ -15,9 +16,9 @@ static InteropService()
                 t.GetFields()[0].GetValue(null);
         }
 
-        public static long GetPrice(uint hash, EvaluationStack stack)
+        public static long GetPrice(uint hash, EvaluationStack stack, StoreView snapshot)
         {
-            return methods[hash].GetPrice(stack);
+            return methods[hash].GetPrice(stack, snapshot);
         }
 
         public static IEnumerable<InteropDescriptor> SupportedMethods()
@@ -44,7 +45,7 @@ private static InteropDescriptor Register(string method, Func<ApplicationEngine,
             return descriptor;
         }
 
-        private static InteropDescriptor Register(string method, Func<ApplicationEngine, bool> handler, Func<EvaluationStack, long> priceCalculator, TriggerType allowedTriggers, CallFlags requiredCallFlags)
+        private static InteropDescriptor Register(string method, Func<ApplicationEngine, bool> handler, Func<EvaluationStack, StoreView, long> priceCalculator, TriggerType allowedTriggers, CallFlags requiredCallFlags)
         {
             InteropDescriptor descriptor = new InteropDescriptor(method, handler, priceCalculator, allowedTriggers, requiredCallFlags);
             methods.Add(descriptor.Hash, descriptor);

src/neo/SmartContract/Native/NativeContract.cs

@@ -2,6 +2,7 @@
 
 using Neo.IO;
 using Neo.Ledger;
+using Neo.Persistence;
 using Neo.SmartContract.Manifest;
 using Neo.SmartContract.Native.Tokens;
 using Neo.VM;
@@ -101,7 +102,7 @@ internal bool Invoke(ApplicationEngine engine)
             return true;
         }
 
-        internal long GetPrice(EvaluationStack stack)
+        internal long GetPrice(EvaluationStack stack, StoreView snapshot)
         {
             return methods.TryGetValue(stack.Peek().GetString(), out ContractMethodMetadata method) ? method.Price : 0;
         }

src/neo/Wallets/Wallet.cs

@@ -354,7 +354,7 @@ public static long CalculateNetworkFee(byte[] witness_script, ref int size)
             if (witness_script.IsSignatureContract())
             {
                 size += 67 + witness_script.GetVarSize();
-                networkFee += ApplicationEngine.OpCodePrices[OpCode.PUSHDATA1] + ApplicationEngine.OpCodePrices[OpCode.PUSHDATA1] + ApplicationEngine.OpCodePrices[OpCode.PUSHNULL] + InteropService.GetPrice(InteropService.Crypto.ECDsaVerify, null);
+                networkFee += ApplicationEngine.OpCodePrices[OpCode.PUSHDATA1] + ApplicationEngine.OpCodePrices[OpCode.PUSHDATA1] + ApplicationEngine.OpCodePrices[OpCode.PUSHNULL] + InteropService.GetPrice(InteropService.Crypto.ECDsaVerify, null, null);
             }
             else if (witness_script.IsMultiSigContract(out int m, out int n))
             {
@@ -366,7 +366,7 @@ public static long CalculateNetworkFee(byte[] witness_script, ref int size)
                 networkFee += ApplicationEngine.OpCodePrices[OpCode.PUSHDATA1] * n;
                 using (ScriptBuilder sb = new ScriptBuilder())
                     networkFee += ApplicationEngine.OpCodePrices[(OpCode)sb.EmitPush(n).ToArray()[0]];
-                networkFee += ApplicationEngine.OpCodePrices[OpCode.PUSHNULL] + InteropService.GetPrice(InteropService.Crypto.ECDsaVerify, null) * n;
+                networkFee += ApplicationEngine.OpCodePrices[OpCode.PUSHNULL] + InteropService.GetPrice(InteropService.Crypto.ECDsaVerify, null, null) * n;
             }
             else
             {