Allow to verify import blocks (#1415)

* Verify Import

* Default true

src/neo/Ledger/Blockchain.cs

@@ -23,7 +23,7 @@ public sealed partial class Blockchain : UntypedActor
     {
         public partial class ApplicationExecuted { }
         public class PersistCompleted { public Block Block; }
-        public class Import { public IEnumerable<Block> Blocks; }
+        public class Import { public IEnumerable<Block> Blocks; public bool Verify = true; }
         public class ImportCompleted { }
         public class FillMemoryPool { public IEnumerable<Transaction> Transactions; }
         public class FillCompleted { }
@@ -239,13 +239,15 @@ public Transaction GetTransaction(UInt256 hash)
             return View.GetTransaction(hash);
         }
 
-        private void OnImport(IEnumerable<Block> blocks)
+        private void OnImport(IEnumerable<Block> blocks, bool verify)
         {
             foreach (Block block in blocks)
             {
                 if (block.Index <= Height) continue;
                 if (block.Index != Height + 1)
                     throw new InvalidOperationException();
+                if (verify && !block.Verify(currentSnapshot))
+                    throw new InvalidOperationException();
                 Persist(block);
                 SaveHeaderHashList();
             }
@@ -453,7 +455,7 @@ protected override void OnReceive(object message)
             switch (message)
             {
                 case Import import:
-                    OnImport(import.Blocks);
+                    OnImport(import.Blocks, import.Verify);
                     break;
                 case FillMemoryPool fill:
                     OnFillMemoryPool(fill.Transactions);