Enable nullable globally and fix issues

Directory.Build.props

@@ -0,0 +1,9 @@
+<Project>
+
+  <PropertyGroup>
+    <Nullable>enable</Nullable>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+    <langversion>10.0</langversion>
+  </PropertyGroup>
+
+</Project>

src/Cid.cs

@@ -1,10 +1,8 @@
-using Google.Protobuf;
-using Newtonsoft.Json;
-using System;
-using System.Collections.Generic;
+using System;
 using System.IO;
-using System.Runtime.Serialization;
 using System.Text;
+using Google.Protobuf;
+using Newtonsoft.Json;
 
 namespace Ipfs
 {
@@ -32,11 +30,11 @@ public class Cid : IEquatable<Cid>
         /// </summary>
         public const string DefaultContentType = "dag-pb";
 
-        string encodedValue;
+        string? encodedValue;
         int version;
         string encoding = MultiBase.DefaultAlgorithmName;
         string contentType = DefaultContentType;
-        MultiHash hash;
+        MultiHash? hash;
 
         /// <summary>
         ///   Throws if a property cannot be set.
@@ -50,7 +48,7 @@ public class Cid : IEquatable<Cid>
         /// </remarks>
         void EnsureMutable()
         {
-            if (encodedValue != null)
+            if (encodedValue is not null)
             {
                 throw new NotSupportedException("CID cannot be changed.");
             }
@@ -170,13 +168,13 @@ public MultiHash Hash
         {
             get
             {
-                return hash;
+                return hash ?? throw new InvalidDataException("Hash has not been set");
             }
             set
             {
                 EnsureMutable();
                 hash = value;
-                if (Version == 0 && Hash.Algorithm.Name != "sha2-256")
+                if (Version == 0 && value.Algorithm.Name != "sha2-256")
                 {
                     Version = 1;
                 }
@@ -243,13 +241,10 @@ public string ToString(string format)
                     sb.Append(Version);
                     sb.Append(' ');
                     sb.Append(ContentType);
-                    if (Hash != null)
-                    {
-                        sb.Append(' ');
-                        sb.Append(Hash.Algorithm.Name);
-                        sb.Append(' ');
-                        sb.Append(MultiBase.Encode(Hash.ToArray(), Encoding).Substring(1));
-                    }
+                    sb.Append(' ');
+                    sb.Append(Hash.Algorithm.Name);
+                    sb.Append(' ');
+                    sb.Append(MultiBase.Encode(Hash.ToArray(), Encoding).Substring(1));
                     return sb.ToString();
 
                 default:
@@ -265,14 +260,14 @@ public string ToString(string format)
         ///   The string representation of the <see cref="Cid"/>.
         /// </returns>
         /// <remarks>
-        ///   For <see cref="Version"/> 0, this is equalivalent to the 
+        ///   For <see cref="Version"/> 0, this is equivalent to the 
         ///   <see cref="MultiHash.ToBase58()">base58btc encoding</see>
         ///   of the <see cref="Hash"/>.
         /// </remarks>
         /// <seealso cref="Decode"/>
         public string Encode()
         {
-            if (encodedValue != null)
+            if (encodedValue is not null)
             {
                 return encodedValue;
             }
@@ -293,22 +288,22 @@ public string Encode()
             return encodedValue;
         }
 
-        /// <summary>
-        ///   Converts the specified <see cref="string"/>
-        ///   to an equivalent <see cref="Cid"/> object.
-        /// </summary>
-        /// <param name="input">
-        ///   The <see cref="Cid.Encode">CID encoded</see> string.
-        /// </param>
-        /// <returns>
-        ///   A new <see cref="Cid"/> that is equivalent to <paramref name="input"/>.
-        /// </returns>
-        /// <exception cref="FormatException">
-        ///   When the <paramref name="input"/> can not be decoded.
-        /// </exception>
-        /// <seealso cref="Encode"/>
-        public static Cid Decode(string input)
-        {
+        /// <summary>
+        ///   Converts the specified <see cref="string"/>
+        ///   to an equivalent <see cref="Cid"/> object.
+        /// </summary>
+        /// <param name="input">
+        ///   The <see cref="Cid.Encode">CID encoded</see> string.
+        /// </param>
+        /// <returns>
+        ///   A new <see cref="Cid"/> that is equivalent to <paramref name="input"/>.
+        /// </returns>
+        /// <exception cref="FormatException">
+        ///   When the <paramref name="input"/> can not be decoded.
+        /// </exception>
+        /// <seealso cref="Encode"/>
+        public static Cid Decode(string input)
+        {
             try
             {
                 // SHA2-256 MultiHash is CID v0.
@@ -332,11 +327,11 @@ public static Cid Decode(string input)
                         Hash = new MultiHash(ms)
                     };
                 }
-            }
+            }
             catch (Exception e)
             {
                 throw new FormatException($"Invalid CID '{input}'.", e);
-            }
+            }
         }
 
         /// <summary>
@@ -532,10 +527,10 @@ public override int GetHashCode()
         }
 
         /// <inheritdoc />
-        public override bool Equals(object obj)
+        public override bool Equals(object? obj)
         {
             var that = obj as Cid;
-            return (that == null)
+            return (that is null)
                 ? false
                 : this.Encode() == that.Encode();
         }
@@ -549,17 +544,17 @@ public bool Equals(Cid that)
         /// <summary>
         ///   Value equality.
         /// </summary>
-        public static bool operator ==(Cid a, Cid b)
+        public static bool operator ==(Cid? a, Cid? b)
         {
             if (object.ReferenceEquals(a, b))
             {
                 return true;
             }
-            if (object.ReferenceEquals(a, null))
+            if (a is null)
             {
                 return false;
             }
-            if (object.ReferenceEquals(b, null))
+            if (b is null)
             {
                 return false;
             }
@@ -569,21 +564,9 @@ public bool Equals(Cid that)
         /// <summary>
         ///   Value inequality.
         /// </summary>
-        public static bool operator !=(Cid a, Cid b)
+        public static bool operator !=(Cid? a, Cid? b)
         {
-            if (object.ReferenceEquals(a, b))
-            {
-                return false;
-            }
-            if (object.ReferenceEquals(a, null))
-            {
-                return true;
-            }
-            if (object.ReferenceEquals(b, null))
-            {
-                return true;
-            }
-            return !a.Equals(b);
+            return !(a == b);
         }
 
         /// <summary>
@@ -641,19 +624,17 @@ public override bool CanConvert(Type objectType)
             public override bool CanWrite => true;
 
             /// <inheritdoc />
-            public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+            public override void WriteJson(JsonWriter writer, object? value, JsonSerializer serializer)
             {
                 var cid = value as Cid;
                 writer.WriteValue(cid?.Encode());
             }
 
             /// <inheritdoc />
-            public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+            public override object? ReadJson(JsonReader reader, Type objectType, object? existingValue, JsonSerializer serializer)
             {
-                var s = reader.Value as string;
-                return s == null ? null : Cid.Decode(s);
+                return reader.Value is string s ? Cid.Decode(s) : null;
             }
         }
-
     }
 }

src/CoreApi/AddFileOptions.cs

@@ -1,6 +1,4 @@
 using System;
-using System.Collections.Generic;
-using System.Text;
 
 namespace Ipfs.CoreApi
 {
@@ -14,8 +12,8 @@ public class AddFileOptions
         ///   Determines if the data is pinned to local storage.
         /// </summary>
         /// <value>
-        ///   If <b>true</b> the data is pinned to local storage and will not be
-        ///   garbage collected.  The default is <b>true</b>.
+        ///   If <b>true</b> the data is pinned to local storage and will not be
+        ///   garbage collected.  The default is <b>true</b>.
         /// </value>
         public bool Pin { get; set; } = true;
 
@@ -58,7 +56,7 @@ public class AddFileOptions
         ///   The hashing algorithm name to use.
         /// </summary>
         /// <value>
-        ///   The <see cref="MultiHash"/> algorithm name used to produce the <see cref="Cid"/>.
+        ///   The <see cref="MultiHash"/> algorithm name used to produce the <see cref="Cid"/>.
         ///   Defaults to <see cref="MultiHash.DefaultAlgorithmName"/>.
         /// </value>
         /// <seealso cref="MultiHash"/>
@@ -68,7 +66,7 @@ public class AddFileOptions
         ///   The encoding algorithm name to use.
         /// </summary>
         /// <value>
-        ///   The <see cref="MultiBase"/> algorithm name used to produce the <see cref="Cid"/>.
+        ///   The <see cref="MultiBase"/> algorithm name used to produce the <see cref="Cid"/>.
         ///   Defaults to <see cref="MultiBase.DefaultAlgorithmName"/>.
         /// </value>
         /// <seealso cref="MultiBase"/>
@@ -92,11 +90,11 @@ public class AddFileOptions
         ///   <b>ProtectionKey</b> and <see cref="RawLeaves"/> are mutually exclusive.
         /// </remarks>
         /// <seealso cref="IKeyApi"/>
-        public string ProtectionKey { get; set; }
+        public string? ProtectionKey { get; set; }
 
         /// <summary>
         ///   Used to report the progress of a file transfer.
         /// </summary>
-        public IProgress<TransferProgress> Progress { get; set; }
+        public IProgress<TransferProgress>? Progress { get; set; }
     }
 }

src/CoreApi/BitswapData.cs

@@ -1,6 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Text;
+using System.Collections.Generic;
 
 namespace Ipfs.CoreApi
 {
@@ -17,12 +15,12 @@ public class BitswapData
         /// <summary>
         ///   The content that is wanted.
         /// </summary>
-        public IEnumerable<Cid> Wantlist;
+        public IEnumerable<Cid>? Wantlist;
 
         /// <summary>
         ///   The known peers.
         /// </summary>
-        public IEnumerable<MultiHash> Peers;
+        public IEnumerable<MultiHash>? Peers;
 
         /// <summary>
         ///   The number of blocks sent by other peers.

src/CoreApi/BitswapLedger.cs

@@ -1,8 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Text;
-
-namespace Ipfs.CoreApi
+namespace Ipfs.CoreApi
 {
     /// <summary>
     ///   Statistics on the <see cref="IBitswapApi">bitswap</see> blocks exchanged with another <see cref="Peer"/>.
@@ -16,7 +12,7 @@ public class BitswapLedger
         /// <value>
         ///   The peer that is being monitored.
         /// </value>
-        public Peer Peer { get; set; }
+        public Peer? Peer { get; set; }
 
         /// <summary>
         ///   The number of blocks exchanged with the <see cref="Peer"/>.

src/CoreApi/FileStat.cs

@@ -1,6 +1,4 @@
 using System;
-using System.Collections.Generic;
-using System.Text;
 
 namespace Ipfs.CoreApi
 {
@@ -13,7 +11,7 @@ public class FileStatResult
         /// <summary>
         /// The <see cref="Cid"/> of the file or directory.
         /// </summary>
-        public Cid Hash { get; set; }
+        public Cid? Hash { get; set; }
 
         /// <summary>
         ///   The serialised size (in bytes) of the linked node.