New Denovo feature: verify any transaction

Src/Autarkysoft.Bitcoin/Blockchain/TransactionVerifier.cs

@@ -22,6 +22,20 @@ namespace Autarkysoft.Bitcoin.Blockchain
     /// </summary>
     public class TransactionVerifier : ITransactionVerifier, IDisposable
     {
+        /// <summary>
+        /// A simplified constructor used for testing. Skips setting <see cref="UtxoDb"/> and <see cref="mempool"/>.
+        /// </summary>
+        /// <param name="consensus">Consensus rules to use</param>
+        public TransactionVerifier(IConsensus consensus)
+        {
+            this.consensus = consensus;
+
+            calc = new EllipticCurveCalculator();
+            scrSer = new ScriptSerializer();
+            hash160 = new Ripemd160Sha256();
+            sha256 = new Sha256();
+        }
+
         /// <summary>
         /// Initializes a new instance of <see cref="TransactionVerifier"/> using given parameters.
         /// </summary>
@@ -159,7 +173,7 @@ public bool VerifyCoinbaseOutput(ITransaction coinbase, out string error)
         private bool VerifyP2pkh(ITransaction tx, int index, PushDataOp sigPush, PushDataOp pubPush,
                                  ReadOnlySpan<byte> pubScrData, out string error)
         {
-            var actualHash = hash160.ComputeHash(pubPush.data);
+            byte[] actualHash = hash160.ComputeHash(pubPush.data);
             if (!pubScrData.Slice(3, 20).SequenceEqual(actualHash))
             {
                 error = "Invalid hash.";
@@ -496,7 +510,7 @@ public bool Verify(ITransaction tx, out string error)
         /// <inheritdoc/>
         public bool Verify(ITransaction tx, IUtxo[] utxos, out string error)
         {
-            if (utxos is null ||  tx.TxInList.Length != utxos.Length)
+            if (utxos is null || tx.TxInList.Length != utxos.Length)
             {
                 error = "Invalid number of UTXOs.";
                 return false;

Src/Denovo/Models/UtxoModel.cs

@@ -0,0 +1,68 @@
+// Denovo
+// Copyright (c) 2020 Autarkysoft
+// Distributed under the MIT software license, see the accompanying
+// file LICENCE or http://www.opensource.org/licenses/mit-license.php.
+
+using Autarkysoft.Bitcoin.Blockchain;
+using Autarkysoft.Bitcoin.Blockchain.Scripts;
+using Autarkysoft.Bitcoin.Encoders;
+using Denovo.MVVM;
+
+namespace Denovo.Models
+{
+    public class UtxoModel : InpcBase
+    {
+        public UtxoModel() { }
+
+        public UtxoModel(byte[] txHash, uint index)
+        {
+            TxId = Base16.EncodeReverse(txHash);
+            Index = index;
+        }
+
+
+        private string _txId;
+        public string TxId
+        {
+            get => _txId;
+            set => SetField(ref _txId, value);
+        }
+
+        private uint _index;
+        public uint Index
+        {
+            get => _index;
+            set => SetField(ref _index, value);
+        }
+
+        private ulong _amaount;
+        public ulong Amount
+        {
+            get => _amaount;
+            set => SetField(ref _amaount, value);
+        }
+
+        private string _scr = string.Empty;
+        public string Script
+        {
+            get => _scr;
+            set => SetField(ref _scr, value);
+        }
+
+
+        public bool TryConvertToUtxo(out Utxo result, out string error)
+        {
+            if (!Base16.TryDecode(Script, out byte[] scrBa))
+            {
+                error = "Invalid pubkey script hex.";
+                result = null;
+                return false;
+            }
+
+            var scr = new PubkeyScript(scrBa);
+            result = new Utxo(Index, Amount, scr);
+            error = null;
+            return true;
+        }
+    }
+}

Src/Denovo/ViewModels/MainWindowViewModel.cs

@@ -147,6 +147,12 @@ public async void OpenEcies()
             await WinMan.ShowDialog(vm);
         }
 
+        public async void OpenVerifyTx()
+        {
+            var vm = new VerifyTxViewModel();
+            await WinMan.ShowDialog(vm);
+        }
+
         private Node _selNode;
         public Node SelectedNode
         {

Src/Denovo/ViewModels/VerifyTxViewModel.cs

@@ -0,0 +1,124 @@
+// Denovo
+// Copyright (c) 2020 Autarkysoft
+// Distributed under the MIT software license, see the accompanying
+// file LICENCE or http://www.opensource.org/licenses/mit-license.php.
+
+using Autarkysoft.Bitcoin;
+using Autarkysoft.Bitcoin.Blockchain;
+using Autarkysoft.Bitcoin.Blockchain.Transactions;
+using Autarkysoft.Bitcoin.Encoders;
+using Denovo.Models;
+using Denovo.MVVM;
+using System;
+using System.Linq;
+
+namespace Denovo.ViewModels
+{
+    public class VerifyTxViewModel : VmWithSizeBase
+    {
+        public VerifyTxViewModel() : base(800, 750)
+        {
+            VerifyCommand = new BindableCommand(Verify, () => IsVerifyEnable);
+        }
+
+
+
+        private readonly Transaction tx = new();
+        // TODO: add block height and network type
+        private readonly TransactionVerifier verifier = new(new Consensus(int.MaxValue, NetworkType.MainNet));
+
+
+        private string _txHex;
+        public string TxHex
+        {
+            get => _txHex;
+            set
+            {
+                if (SetField(ref _txHex, value))
+                {
+                    if (string.IsNullOrWhiteSpace(value))
+                    {
+                        Result = "Enter a valid transaction hex.";
+                    }
+                    else if (!Base16.TryDecode(value, out byte[] ba))
+                    {
+                        UtxoList = Array.Empty<UtxoModel>();
+                        IsVerifyEnable = false;
+                        Result = "Invalid hexadecimal transaction.";
+                    }
+                    else if (!tx.TryDeserialize(new FastStreamReader(ba), out string error))
+                    {
+                        UtxoList = Array.Empty<UtxoModel>();
+                        IsVerifyEnable = false;
+                        Result = $"Error deserializing transaction: {error}";
+                    }
+                    else
+                    {
+                        // Has to recompute hashes when more than one tx is verified
+                        tx.ComputeTransactionHashes();
+
+                        Result = string.Empty;
+                        UtxoList = tx.TxInList.Select(x => new UtxoModel(x.TxHash, x.Index)).ToArray();
+                        IsVerifyEnable = true;
+                    }
+                }
+            }
+        }
+
+        private UtxoModel[] _utxos;
+        public UtxoModel[] UtxoList
+        {
+            get => _utxos;
+            private set => SetField(ref _utxos, value);
+        }
+
+        private string _res;
+        public string Result
+        {
+            get => _res;
+            private set => SetField(ref _res, value);
+        }
+
+        private bool _isEnable;
+        public bool IsVerifyEnable
+        {
+            get => _isEnable;
+            private set
+            {
+                if (SetField(ref _isEnable, value))
+                {
+                    VerifyCommand.RaiseCanExecuteChanged();
+                }
+            }
+        }
+
+
+        public BindableCommand VerifyCommand { get; private set; }
+        private void Verify()
+        {
+            var temp = new Utxo[UtxoList.Length];
+            for (int i = 0; i < UtxoList.Length; i++)
+            {
+                if (!UtxoList[i].TryConvertToUtxo(out Utxo u, out string error))
+                {
+                    Result = $"Failed to set UTXO at index = {i}.{Environment.NewLine}{error}";
+                    return;
+                }
+
+                temp[i] = u;
+            }
+
+            verifier.Init();
+            if (verifier.Verify(tx, temp, out string err))
+            {
+                Result = $"Transaction is valid (assuming all given UTXOs existed and were unspent at the time)." +
+                         $"{Environment.NewLine}Transaction fee: {verifier.TotalFee} satoshi" +
+                         $"{Environment.NewLine}Transaction SigOp count: {verifier.TotalSigOpCount}";
+            }
+            else
+            {
+                Result = $"Failed to verify the given transaction. Error: {err}";
+            }
+        }
+    }
+}

Src/Denovo/Views/MainWindow.xaml

@@ -26,6 +26,7 @@
           <Button Content="Config" Command="{Binding OpenConfig}" Width="100" HorizontalAlignment="Left"/>
           <Button Content="Miner" Command="{Binding OpenMiner}" Width="100" HorizontalAlignment="Left"/>
           <Button Content="Encrypt/Decrypt" Command="{Binding OpenEcies}" HorizontalAlignment="Left"/>
+          <Button Content="Transaction verifier" Command="{Binding OpenVerifyTx}" HorizontalAlignment="Left"/>
         </StackPanel>
         <StackPanel Orientation="Horizontal" Spacing="5">
           <TextBlock Text="IP:"/>

Src/Denovo/Views/VerifyTxView.axaml

@@ -0,0 +1,68 @@
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             xmlns:vm="clr-namespace:Denovo.ViewModels;assembly=Denovo"
+             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="550"
+             x:Class="Denovo.Views.VerifyTxView"
+             FontSize="14">
+
+  <Design.DataContext>
+    <vm:VerifyTxViewModel/>
+  </Design.DataContext>
+
+  <Grid RowDefinitions="100,*,auto,70">
+    <TextBox Text="{Binding TxHex}"
+             Watermark="Transaction hex"
+             ScrollViewer.VerticalScrollBarVisibility="Visible"
+             Grid.Row="0"/>
+
+    <ItemsControl Items="{Binding UtxoList}" Grid.Row="1" ScrollViewer.VerticalScrollBarVisibility="Visible">
+      <ItemsControl.ItemsPanel>
+        <ItemsPanelTemplate>
+          <StackPanel Orientation="Vertical"/>
+        </ItemsPanelTemplate>
+      </ItemsControl.ItemsPanel>
+      <ItemsControl.ItemTemplate>
+        <DataTemplate>
+          <StackPanel Orientation="Horizontal">
+            <TextBox Text="{Binding TxId}"
+                     TextWrapping="NoWrap"
+                     ToolTip.Tip="Transaction ID"
+                     Watermark="Transaction ID"
+                     UseFloatingWatermark="False"
+                     Width="150"/>
+
+            <TextBox Text="{Binding Index}"
+                     ToolTip.Tip="Index"
+                     Watermark="Index"
+                     UseFloatingWatermark="False"
+                     Width="50"/>
+
+            <TextBox Text="{Binding Amount}"
+                     ToolTip.Tip="Amount (satoshi)"
+                     Watermark="Amount (satoshi)"
+                     UseFloatingWatermark="False"
+                     Width="150"/>
+
+            <TextBox Text="{Binding Script}"
+                     TextWrapping="NoWrap"
+                     ToolTip.Tip="Script (hex)"
+                     Watermark="Script (hex)"
+                     UseFloatingWatermark="False"
+                     Width="370"/>
+          </StackPanel>
+        </DataTemplate>
+      </ItemsControl.ItemTemplate>
+    </ItemsControl>
+
+    <Button Content="Verify"
+            Command="{Binding VerifyCommand}"
+            Margin="5"
+            Grid.Row="2"/>
+
+    <TextBox Text="{Binding Result, Mode=OneWay}"
+             IsReadOnly="True"
+             Grid.Row="3"/>
+  </Grid>
+</UserControl>

Src/Denovo/Views/VerifyTxView.axaml.cs

@@ -0,0 +1,16 @@
+// Denovo
+// Copyright (c) 2020 Autarkysoft
+// Distributed under the MIT software license, see the accompanying
+// file LICENCE or http://www.opensource.org/licenses/mit-license.php.
+
+using Avalonia.Controls;
+using Avalonia.Markup.Xaml;
+
+namespace Denovo.Views
+{
+    public partial class VerifyTxView : UserControl
+    {
+        public VerifyTxView() => InitializeComponent();
+        private void InitializeComponent() => AvaloniaXamlLoader.Load(this);
+    }
+}