[Neo Core] Nullable

src/Neo/Cryptography/Crypto.cs

@@ -80,8 +80,8 @@ public static bool VerifySignature(ReadOnlySpan<byte> message, ReadOnlySpan<byte
                 var curve = Org.BouncyCastle.Asn1.Sec.SecNamedCurves.GetByName("secp256k1");
                 var domain = new Org.BouncyCastle.Crypto.Parameters.ECDomainParameters(curve.Curve, curve.G, curve.N, curve.H);
                 var point = curve.Curve.CreatePoint(
-                    new Org.BouncyCastle.Math.BigInteger(pubkey.X.Value.ToString()),
-                    new Org.BouncyCastle.Math.BigInteger(pubkey.Y.Value.ToString()));
+                    new Org.BouncyCastle.Math.BigInteger(pubkey.X!.Value.ToString()),
+                    new Org.BouncyCastle.Math.BigInteger(pubkey.Y!.Value.ToString()));
                 var pubKey = new Org.BouncyCastle.Crypto.Parameters.ECPublicKeyParameters("ECDSA", point, domain);
                 var signer = new Org.BouncyCastle.Crypto.Signers.ECDsaSigner();
                 signer.Init(false, pubKey);

src/Neo/Cryptography/ECC/ECFieldElement.cs

@@ -29,14 +29,14 @@ public ECFieldElement(BigInteger value, ECCurve curve)
             this.curve = curve;
         }
 
-        public int CompareTo(ECFieldElement other)
+        public int CompareTo(ECFieldElement? other)
         {
             if (ReferenceEquals(this, other)) return 0;
-            if (!curve.Equals(other.curve)) throw new InvalidOperationException("Invalid comparision for points with different curves");
+            if (!curve.Equals(other?.curve)) throw new InvalidOperationException("Invalid comparision for points with different curves");
             return Value.CompareTo(other.Value);
         }
 
-        public override bool Equals(object obj)
+        public override bool Equals(object? obj)
         {
             if (obj == this)
                 return true;
@@ -47,9 +47,9 @@ public override bool Equals(object obj)
             return Equals(other);
         }
 
-        public bool Equals(ECFieldElement other)
+        public bool Equals(ECFieldElement? other)
         {
-            return Value.Equals(other.Value) && curve.Equals(other.curve);
+            return Value.Equals(other?.Value) && curve.Equals(other.curve);
         }
 
         private static BigInteger[] FastLucasSequence(BigInteger p, BigInteger P, BigInteger Q, BigInteger k)
@@ -104,7 +104,7 @@ public override int GetHashCode()
             return Value.GetHashCode();
         }
 
-        public ECFieldElement Sqrt()
+        public ECFieldElement? Sqrt()
         {
             if (curve.Q.TestBit(1))
             {

src/Neo/Cryptography/ECC/ECPoint.cs

@@ -23,9 +23,9 @@ namespace Neo.Cryptography.ECC
     /// </summary>
     public class ECPoint : IComparable<ECPoint>, IEquatable<ECPoint>, ISerializable
     {
-        internal ECFieldElement X, Y;
+        internal ECFieldElement? X, Y;
         internal readonly ECCurve Curve;
-        private byte[] _compressedPoint, _uncompressedPoint;
+        private byte[]? _compressedPoint, _uncompressedPoint;
 
         /// <summary>
         /// Indicates whether it is a point at infinity.
@@ -37,15 +37,15 @@ public bool IsInfinity
 
         public int Size => IsInfinity ? 1 : 33;
 
-        private static IO.Caching.ECPointCache pointCacheK1 { get; } = new(1000);
-        private static IO.Caching.ECPointCache pointCacheR1 { get; } = new(1000);
+        private static ECPointCache pointCacheK1 { get; } = new(1000);
+        private static ECPointCache pointCacheR1 { get; } = new(1000);
 
         /// <summary>
         /// Initializes a new instance of the <see cref="ECPoint"/> class with the secp256r1 curve.
         /// </summary>
         public ECPoint() : this(null, null, ECCurve.Secp256r1) { }
 
-        internal ECPoint(ECFieldElement x, ECFieldElement y, ECCurve curve)
+        internal ECPoint(ECFieldElement? x, ECFieldElement? y, ECCurve curve)
         {
             if ((x is null ^ y is null) || (curve is null))
                 throw new ArgumentException("Exactly one of the field elements is null");
@@ -54,13 +54,13 @@ internal ECPoint(ECFieldElement x, ECFieldElement y, ECCurve curve)
             this.Curve = curve;
         }
 
-        public int CompareTo(ECPoint other)
+        public int CompareTo(ECPoint? other)
         {
-            if (!Curve.Equals(other.Curve)) throw new InvalidOperationException("Invalid comparision for points with different curves");
+            if (!Curve.Equals(other?.Curve)) throw new InvalidOperationException("Invalid comparision for points with different curves");
             if (ReferenceEquals(this, other)) return 0;
-            int result = X.CompareTo(other.X);
+            int result = X!.CompareTo(other.X);
             if (result != 0) return result;
-            return Y.CompareTo(other.Y);
+            return Y!.CompareTo(other.Y);
         }
 
         /// <summary>
@@ -71,7 +71,7 @@ public int CompareTo(ECPoint other)
         /// <returns>The decoded point.</returns>
         public static ECPoint DecodePoint(ReadOnlySpan<byte> encoded, ECCurve curve)
         {
-            ECPoint p = null;
+            ECPoint? p = null;
             switch (encoded[0])
             {
                 case 0x02: // compressed
@@ -102,7 +102,7 @@ public static ECPoint DecodePoint(ReadOnlySpan<byte> encoded, ECCurve curve)
 
         private static ECPoint DecompressPoint(ReadOnlySpan<byte> encoded, ECCurve curve)
         {
-            ECPointCache pointCache = null;
+            ECPointCache? pointCache;
             if (curve == ECCurve.Secp256k1) pointCache = pointCacheK1;
             else if (curve == ECCurve.Secp256r1) pointCache = pointCacheR1;
             else throw new FormatException("Invalid curve " + curve);
@@ -123,7 +123,7 @@ private static ECPoint DecompressPoint(int yTilde, BigInteger X1, ECCurve curve)
         {
             ECFieldElement x = new(X1, curve);
             ECFieldElement alpha = x * (x.Square() + curve.A) + curve.B;
-            ECFieldElement beta = alpha.Sqrt();
+            ECFieldElement? beta = alpha.Sqrt();
 
             //
             // if we can't find a sqrt we haven't got a point on the
@@ -187,27 +187,27 @@ public byte[] EncodePoint(bool commpressed)
             {
                 if (_uncompressedPoint != null) return _uncompressedPoint;
                 data = new byte[65];
-                byte[] yBytes = Y.Value.ToByteArray(isUnsigned: true, isBigEndian: true);
+                byte[] yBytes = Y!.Value.ToByteArray(isUnsigned: true, isBigEndian: true);
                 Buffer.BlockCopy(yBytes, 0, data, 65 - yBytes.Length, yBytes.Length);
             }
-            byte[] xBytes = X.Value.ToByteArray(isUnsigned: true, isBigEndian: true);
+            byte[] xBytes = X!.Value.ToByteArray(isUnsigned: true, isBigEndian: true);
             Buffer.BlockCopy(xBytes, 0, data, 33 - xBytes.Length, xBytes.Length);
-            data[0] = commpressed ? Y.Value.IsEven ? (byte)0x02 : (byte)0x03 : (byte)0x04;
+            data[0] = commpressed ? Y!.Value.IsEven ? (byte)0x02 : (byte)0x03 : (byte)0x04;
             if (commpressed) _compressedPoint = data;
             else _uncompressedPoint = data;
             return data;
         }
 
-        public bool Equals(ECPoint other)
+        public bool Equals(ECPoint? other)
         {
             if (ReferenceEquals(this, other)) return true;
             if (other is null) return false;
             if (IsInfinity && other.IsInfinity) return true;
             if (IsInfinity || other.IsInfinity) return false;
-            return X.Equals(other.X) && Y.Equals(other.Y);
+            return X!.Equals(other.X) && Y!.Equals(other.Y);
         }
 
-        public override bool Equals(object obj)
+        public override bool Equals(object? obj)
         {
             return Equals(obj as ECPoint);
         }
@@ -231,7 +231,7 @@ public static ECPoint FromBytes(byte[] bytes, ECCurve curve)
 
         public override int GetHashCode()
         {
-            return X.GetHashCode() + Y.GetHashCode();
+            return X!.GetHashCode() + Y!.GetHashCode();
         }
 
         internal static ECPoint Multiply(ECPoint p, BigInteger k)
@@ -361,7 +361,7 @@ public override string ToString()
         /// <param name="curve">The <see cref="ECCurve"/> object used to construct the <see cref="ECPoint"/>.</param>
         /// <param name="point">The parsed point.</param>
         /// <returns><see langword="true"/> if <paramref name="value"/> was converted successfully; otherwise, <see langword="false"/>.</returns>
-        public static bool TryParse(string value, ECCurve curve, out ECPoint point)
+        public static bool TryParse(string value, ECCurve curve, out ECPoint? point)
         {
             try
             {
@@ -379,13 +379,13 @@ internal ECPoint Twice()
         {
             if (this.IsInfinity)
                 return this;
-            if (this.Y.Value.Sign == 0)
+            if (this.Y?.Value.Sign == 0)
                 return Curve.Infinity;
             ECFieldElement TWO = new(2, Curve);
             ECFieldElement THREE = new(3, Curve);
-            ECFieldElement gamma = (this.X.Square() * THREE + Curve.A) / (Y * TWO);
+            ECFieldElement gamma = (this.X!.Square() * THREE + Curve.A) / (Y! * TWO);
             ECFieldElement x3 = gamma.Square() - this.X * TWO;
-            ECFieldElement y3 = gamma * (this.X - x3) - this.Y;
+            ECFieldElement y3 = gamma * (this.X - x3) - this.Y!;
             return new ECPoint(x3, y3, Curve);
         }
 
@@ -426,7 +426,7 @@ private static sbyte[] WindowNaf(sbyte width, BigInteger k)
 
         public static ECPoint operator -(ECPoint x)
         {
-            return new ECPoint(x.X, -x.Y, x.Curve);
+            return new ECPoint(x.X, -x.Y!, x.Curve);
         }
 
         public static ECPoint operator *(ECPoint p, byte[] n)
@@ -449,15 +449,15 @@ private static sbyte[] WindowNaf(sbyte width, BigInteger k)
                 return y;
             if (y.IsInfinity)
                 return x;
-            if (x.X.Equals(y.X))
+            if (x.X!.Equals(y.X))
             {
-                if (x.Y.Equals(y.Y))
+                if (x.Y!.Equals(y.Y))
                     return x.Twice();
                 return x.Curve.Infinity;
             }
-            ECFieldElement gamma = (y.Y - x.Y) / (y.X - x.X);
-            ECFieldElement x3 = gamma.Square() - x.X - y.X;
-            ECFieldElement y3 = gamma * (x.X - x3) - x.Y;
+            ECFieldElement gamma = (y.Y! - x.Y!) / (y.X! - x.X);
+            ECFieldElement x3 = gamma.Square() - x.X - y.X!;
+            ECFieldElement y3 = gamma * (x.X - x3) - x.Y!;
             return new ECPoint(x3, y3, x.Curve);
         }
 

src/Neo/Cryptography/Helper.cs

@@ -153,7 +153,7 @@ public static byte[] Sha256(this Span<byte> value)
             return Sha256((ReadOnlySpan<byte>)value);
         }
 
-        public static byte[] AES256Encrypt(this byte[] plainData, byte[] key, byte[] nonce, byte[] associatedData = null)
+        public static byte[] AES256Encrypt(this byte[] plainData, byte[] key, byte[] nonce, byte[]? associatedData = null)
         {
             if (nonce.Length != 12) throw new ArgumentOutOfRangeException(nameof(nonce));
             var tag = new byte[16];
@@ -179,7 +179,7 @@ public static byte[] AES256Encrypt(this byte[] plainData, byte[] key, byte[] non
             return Concat(nonce, cipherBytes, tag);
         }
 
-        public static byte[] AES256Decrypt(this byte[] encryptedData, byte[] key, byte[] associatedData = null)
+        public static byte[] AES256Decrypt(this byte[] encryptedData, byte[] key, byte[]? associatedData = null)
         {
             ReadOnlySpan<byte> encrypted = encryptedData;
             var nonce = encrypted[..12];

src/Neo/Cryptography/MerkleTree.cs

@@ -23,7 +23,7 @@ namespace Neo.Cryptography
     /// </summary>
     public class MerkleTree
     {
-        private readonly MerkleTreeNode root;
+        private readonly MerkleTreeNode? root;
 
         /// <summary>
         /// The depth of the tree.
@@ -40,7 +40,7 @@ internal MerkleTree(UInt256[] hashes)
             this.Depth = depth;
         }
 
-        private static MerkleTreeNode Build(MerkleTreeNode[] leaves)
+        private static MerkleTreeNode? Build(MerkleTreeNode[] leaves)
         {
             if (leaves.Length == 0) return null;
             if (leaves.Length == 1) return leaves[0];
@@ -63,7 +63,7 @@ private static MerkleTreeNode Build(MerkleTreeNode[] leaves)
                     parents[i].RightChild = leaves[i * 2 + 1];
                     leaves[i * 2 + 1].Parent = parents[i];
                 }
-                parents[i].Hash = Concat(buffer, parents[i].LeftChild.Hash, parents[i].RightChild.Hash);
+                parents[i].Hash = Concat(buffer, parents[i].LeftChild!.Hash, parents[i].RightChild!.Hash);
             }
             return Build(parents); //TailCall
         }
@@ -87,7 +87,7 @@ public static UInt256 ComputeRoot(UInt256[] hashes)
             if (hashes.Length == 0) return UInt256.Zero;
             if (hashes.Length == 1) return hashes[0];
             MerkleTree tree = new(hashes);
-            return tree.root.Hash;
+            return tree.root!.Hash;
         }
 
         private static void DepthFirstSearch(MerkleTreeNode node, IList<UInt256> hashes)
@@ -100,7 +100,7 @@ private static void DepthFirstSearch(MerkleTreeNode node, IList<UInt256> hashes)
             else
             {
                 DepthFirstSearch(node.LeftChild, hashes);
-                DepthFirstSearch(node.RightChild, hashes);
+                DepthFirstSearch(node.RightChild!, hashes);
             }
         }
 
@@ -145,8 +145,8 @@ private static void Trim(MerkleTreeNode node, int index, int depth, BitArray fla
             else
             {
                 Trim(node.LeftChild, index * 2, depth - 1, flags);
-                Trim(node.RightChild, index * 2 + 1, depth - 1, flags);
-                if (node.LeftChild.LeftChild == null && node.RightChild.RightChild == null)
+                Trim(node.RightChild!, index * 2 + 1, depth - 1, flags);
+                if (node.LeftChild.LeftChild == null && node.RightChild!.RightChild == null)
                 {
                     node.LeftChild = null;
                     node.RightChild = null;

src/Neo/Cryptography/MerkleTreeNode.cs

@@ -13,10 +13,10 @@ namespace Neo.Cryptography
 {
     internal class MerkleTreeNode
     {
-        public UInt256 Hash;
-        public MerkleTreeNode Parent;
-        public MerkleTreeNode LeftChild;
-        public MerkleTreeNode RightChild;
+        public UInt256 Hash = null!;
+        public MerkleTreeNode? Parent;
+        public MerkleTreeNode? LeftChild;
+        public MerkleTreeNode? RightChild;
 
         public bool IsLeaf => LeftChild == null && RightChild == null;
 

src/Neo/Helper.cs

@@ -135,19 +135,19 @@ internal static void Remove<T, V>(this HashSet<T> set, IReadOnlyDictionary<T, V>
 
         internal static string GetVersion(this Assembly assembly)
         {
-            CustomAttributeData attribute = assembly.CustomAttributes.FirstOrDefault(p => p.AttributeType == typeof(AssemblyInformationalVersionAttribute));
-            if (attribute == null) return assembly.GetName().Version.ToString(3);
-            return (string)attribute.ConstructorArguments[0].Value;
+            CustomAttributeData? attribute = assembly.CustomAttributes.FirstOrDefault(p => p.AttributeType == typeof(AssemblyInformationalVersionAttribute));
+            if (attribute == null) return assembly.GetName().Version!.ToString(3);
+            return (string)attribute.ConstructorArguments[0].Value!;
         }
 
         /// <summary>
         /// Converts a hex <see cref="string"/> to byte array.
         /// </summary>
         /// <param name="value">The hex <see cref="string"/> to convert.</param>
         /// <returns>The converted byte array.</returns>
-        public static byte[] HexToBytes(this string value)
+        public static byte[] HexToBytes(this string? value)
         {
-            if (value == null || value.Length == 0)
+            if (string.IsNullOrEmpty(value))
                 return Array.Empty<byte>();
             if (value.Length % 2 == 1)
                 throw new FormatException();
@@ -309,5 +309,25 @@ internal static IPEndPoint Unmap(this IPEndPoint endPoint)
                 return endPoint;
             return new IPEndPoint(endPoint.Address.Unmap(), endPoint.Port);
         }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        internal static T NullExceptionOr<T>(this object? obj) where T : class
+        {
+            if (obj == null) throw new NullReferenceException($"Object {nameof(obj)} is null.");
+            return (T)obj;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        internal static T NotNull<T>(this T? obj) where T : class
+        {
+            return obj.NotNull($"Object {nameof(obj)} is null.");
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        internal static T NotNull<T>(this T? obj, string msg) where T : class
+        {
+            if (obj == null) throw new NullReferenceException(msg);
+            return obj;
+        }
     }
 }

src/Neo/IO/ByteArrayComparer.cs

@@ -27,8 +27,14 @@ private ByteArrayComparer(int direction)
             this.direction = direction;
         }
 
-        public int Compare(byte[] x, byte[] y)
+        public int Compare(byte[]? x, byte[]? y)
         {
+            if (x == null || y == null)
+            {
+                if (x == null && y == null) return 0;
+                return x == null ? -1 : 1;
+            }
+
             return direction > 0
                 ? CompareInternal(x, y)
                 : -CompareInternal(x, y);

src/Neo/IO/ByteArrayEqualityComparer.cs

@@ -17,7 +17,7 @@ internal class ByteArrayEqualityComparer : IEqualityComparer<byte[]>
     {
         public static readonly ByteArrayEqualityComparer Default = new();
 
-        public unsafe bool Equals(byte[] x, byte[] y)
+        public unsafe bool Equals(byte[]? x, byte[]? y)
         {
             if (ReferenceEquals(x, y)) return true;
             if (x is null || y is null) return false;