Add Designate contract

src/neo/Network/P2P/Payloads/OracleResponse.cs

@@ -70,7 +70,7 @@ public override bool Verify(StoreView snapshot, Transaction tx)
             OracleRequest request = NativeContract.Oracle.GetRequest(snapshot, Id);
             if (request is null) return false;
             if (tx.NetworkFee + tx.SystemFee != request.GasForResponse) return false;
-            UInt160 oracleAccount = Blockchain.GetConsensusAddress(NativeContract.Oracle.GetOracleNodes(snapshot));
+            UInt160 oracleAccount = Blockchain.GetConsensusAddress(NativeContract.Designate.GetDesignatedByRole(snapshot, Role.Oracle));
             return tx.Signers.Any(p => p.Account.Equals(oracleAccount));
         }
     }

src/neo/SmartContract/Native/DesignateContract.cs

@@ -0,0 +1,70 @@
+using Neo.Cryptography;
+using Neo.Cryptography.ECC;
+using Neo.IO;
+using Neo.Ledger;
+using Neo.Persistence;
+using Neo.SmartContract.Manifest;
+using Neo.VM;
+using Neo.VM.Types;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Neo.SmartContract.Native
+{
+    public enum Role : byte
+    {
+        StateValidator = 4,
+        Oracle = 8
+    }
+
+    public sealed class DesignateContract : NativeContract
+    {
+        public override string Name => "Designation";
+        public override int Id => -5;
+
+        internal DesignateContract()
+        {
+            Manifest.Features = ContractFeatures.HasStorage;
+        }
+
+        internal override void Initialize(ApplicationEngine engine)
+        {
+            foreach (var role in Enum.GetValues(typeof(Role)))
+            {
+                engine.Snapshot.Storages.Add(CreateStorageKey((byte)role), new StorageItem(new NodeList()));
+            }
+        }
+
+        [ContractMethod(0_01000000, CallFlags.AllowStates)]
+        public ECPoint[] GetDesignatedByRole(StoreView snapshot, Role role)
+        {
+            return snapshot.Storages[CreateStorageKey((byte)role)].GetInteroperable<NodeList>().ToArray();
+        }
+
+        [ContractMethod(0, CallFlags.AllowModifyStates)]
+        private void DesignateAsRole(ApplicationEngine engine, ECPoint[] nodes, Role role)
+        {
+            if (nodes.Length == 0) throw new ArgumentException();
+            if (!CheckCommittee(engine)) throw new InvalidOperationException();
+            NodeList list = engine.Snapshot.Storages.GetAndChange(CreateStorageKey((byte)role)).GetInteroperable<NodeList>();
+            list.Clear();
+            list.AddRange(nodes);
+            list.Sort();
+        }
+
+        private class NodeList : List<ECPoint>, IInteroperable
+        {
+            public void FromStackItem(StackItem stackItem)
+            {
+                foreach (StackItem item in (Neo.VM.Types.Array)stackItem)
+                    Add(ECPoint.DecodePoint(item.GetSpan(), ECCurve.Secp256r1));
+            }
+
+            public StackItem ToStackItem(ReferenceCounter referenceCounter)
+            {
+                return new Neo.VM.Types.Array(referenceCounter, this.Select(p => (StackItem)p.ToArray()));
+            }
+        }
+    }
+}

src/neo/SmartContract/Native/NativeContract.cs

@@ -25,6 +25,7 @@ public abstract class NativeContract
         public static GasToken GAS { get; } = new GasToken();
         public static PolicyContract Policy { get; } = new PolicyContract();
         public static OracleContract Oracle { get; } = new OracleContract();
+        public static DesignateContract Designate { get; } = new DesignateContract();
 
         [ContractMethod(0, CallFlags.None)]
         public abstract string Name { get; }

src/neo/SmartContract/Native/Oracle/OracleContract.Lists.cs

@@ -1,5 +1,3 @@
-using Neo.Cryptography.ECC;
-using Neo.IO;
 using Neo.VM;
 using Neo.VM.Types;
 using System.Collections.Generic;
@@ -22,19 +20,5 @@ public StackItem ToStackItem(ReferenceCounter referenceCounter)
                 return new Array(referenceCounter, this.Select(p => (Integer)p));
             }
         }
-
-        private class NodeList : List<ECPoint>, IInteroperable
-        {
-            public void FromStackItem(StackItem stackItem)
-            {
-                foreach (StackItem item in (Array)stackItem)
-                    Add(ECPoint.DecodePoint(item.GetSpan(), ECCurve.Secp256r1));
-            }
-
-            public StackItem ToStackItem(ReferenceCounter referenceCounter)
-            {
-                return new Array(referenceCounter, this.Select(p => (StackItem)p.ToArray()));
-            }
-        }
     }
 }

src/neo/SmartContract/Native/Oracle/OracleContract.cs

@@ -1,7 +1,6 @@
 #pragma warning disable IDE0051
 
 using Neo.Cryptography;
-using Neo.Cryptography.ECC;
 using Neo.Ledger;
 using Neo.Network.P2P.Payloads;
 using Neo.Persistence;
@@ -21,7 +20,6 @@ public sealed partial class OracleContract : NativeContract
         private const int MaxCallbackLength = 32;
         private const int MaxUserDataLength = 512;
 
-        private const byte Prefix_NodeList = 8;
         private const byte Prefix_RequestId = 9;
         private const byte Prefix_Request = 7;
         private const byte Prefix_IdList = 6;
@@ -48,12 +46,6 @@ private void Finish(ApplicationEngine engine)
             engine.CallFromNativeContract(null, request.CallbackContract, request.CallbackMethod, request.Url, userData, (int)response.Code, response.Result);
         }
 
-        [ContractMethod(0_01000000, CallFlags.AllowStates)]
-        public ECPoint[] GetOracleNodes(StoreView snapshot)
-        {
-            return snapshot.Storages[CreateStorageKey(Prefix_NodeList)].GetInteroperable<NodeList>().ToArray();
-        }
-
         private UInt256 GetOriginalTxid(ApplicationEngine engine)
         {
             Transaction tx = (Transaction)engine.ScriptContainer;
@@ -88,7 +80,6 @@ private static byte[] GetUrlHash(string url)
 
         internal override void Initialize(ApplicationEngine engine)
         {
-            engine.Snapshot.Storages.Add(CreateStorageKey(Prefix_NodeList), new StorageItem(new NodeList()));
             engine.Snapshot.Storages.Add(CreateStorageKey(Prefix_RequestId), new StorageItem(BitConverter.GetBytes(0ul)));
         }
 
@@ -114,7 +105,7 @@ protected override void PostPersist(ApplicationEngine engine)
                 if (list.Count == 0) engine.Snapshot.Storages.Delete(key);
 
                 //Mint GAS for oracle nodes
-                nodes ??= GetOracleNodes(engine.Snapshot).Select(p => (Contract.CreateSignatureRedeemScript(p).ToScriptHash(), BigInteger.Zero)).ToArray();
+                nodes ??= NativeContract.Designate.GetDesignatedByRole(engine.Snapshot, Native.Role.Oracle).Select(p => (Contract.CreateSignatureRedeemScript(p).ToScriptHash(), BigInteger.Zero)).ToArray();
                 if (nodes.Length > 0)
                 {
                     int index = (int)(response.Id % (ulong)nodes.Length);
@@ -167,17 +158,6 @@ private void Request(ApplicationEngine engine, string url, string filter, string
             engine.Snapshot.Storages.GetAndChange(CreateStorageKey(Prefix_IdList).Add(GetUrlHash(url)), () => new StorageItem(new IdList())).GetInteroperable<IdList>().Add(id);
         }
 
-        [ContractMethod(0, CallFlags.AllowModifyStates)]
-        private void SetOracleNodes(ApplicationEngine engine, ECPoint[] nodes)
-        {
-            if (nodes.Length == 0) throw new ArgumentException();
-            if (!CheckCommittee(engine)) throw new InvalidOperationException();
-            NodeList list = engine.Snapshot.Storages.GetAndChange(CreateStorageKey(Prefix_NodeList)).GetInteroperable<NodeList>();
-            list.Clear();
-            list.AddRange(nodes);
-            list.Sort();
-        }
-
         [ContractMethod(0_01000000, CallFlags.None)]
         private bool Verify(ApplicationEngine engine)
         {