Allow contracts to load script at runtime dynamically (#2756)

* Allow contracts to load script at runtime dynamically

* Improve

* Prevent notifications in dynamic scripts

* Fix UT

* Fix CalledByEntryCondition

* rename

* readonly

src/Neo/SmartContract/ApplicationEngine.Runtime.cs

@@ -12,6 +12,7 @@
 using Neo.IO;
 using Neo.Network.P2P.Payloads;
 using Neo.SmartContract.Native;
+using Neo.VM;
 using Neo.VM.Types;
 using System;
 using System.Collections.Generic;
@@ -90,6 +91,12 @@ partial class ApplicationEngine
         /// </summary>
         public static readonly InteropDescriptor System_Runtime_GetEntryScriptHash = Register("System.Runtime.GetEntryScriptHash", nameof(EntryScriptHash), 1 << 4, CallFlags.None);
 
+        /// <summary>
+        /// The <see cref="InteropDescriptor"/> of System.Runtime.LoadScript.
+        /// Loads a script at rumtime.
+        /// </summary>
+        public static readonly InteropDescriptor System_Runtime_LoadScript = Register("System.Runtime.LoadScript", nameof(RuntimeLoadScript), 1 << 15, CallFlags.AllowCall);
+
         /// <summary>
         /// The <see cref="InteropDescriptor"/> of System.Runtime.CheckWitness.
         /// Determines whether the specified account has witnessed the current transaction.
@@ -189,6 +196,27 @@ protected internal StackItem GetScriptContainer()
             return interop.ToStackItem(ReferenceCounter);
         }
 
+        /// <summary>
+        /// The implementation of System.Runtime.LoadScript.
+        /// Loads a script at rumtime.
+        /// </summary>
+        protected internal void RuntimeLoadScript(byte[] script, CallFlags callFlags, Array args)
+        {
+            if ((callFlags & ~CallFlags.All) != 0)
+                throw new ArgumentOutOfRangeException(nameof(callFlags));
+
+            ExecutionContextState state = CurrentContext.GetState<ExecutionContextState>();
+            ExecutionContext context = LoadScript(script, configureState: p =>
+            {
+                p.CallingContext = CurrentContext;
+                p.CallFlags = callFlags & state.CallFlags & CallFlags.ReadOnly;
+                p.IsDynamicCall = true;
+            });
+
+            for (int i = args.Count - 1; i >= 0; i--)
+                context.EvaluationStack.Push(args[i]);
+        }
+
         /// <summary>
         /// The implementation of System.Runtime.CheckWitness.
         /// Determines whether the specified account has witnessed the current transaction.