Merge pull request #878 from drewnoakes/nullable-reference-types

Nullable reference types

Author: somdoron

src/NetMQ/Annotations.cs

@@ -0,0 +1,90 @@
+// Licensed to the .NET Foundation under one or more agreements. The .NET Foundation licenses this file to you under the MIT license. See the LICENSE.md file in the project root for more information.
+
+#if !NETSTANDARD2_1
+
+namespace System.Diagnostics.CodeAnalysis
+{
+    /// <summary>Specifies that null is allowed as an input even if the corresponding type disallows it.</summary>
+    [AttributeUsage(AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.Property, Inherited = false)]
+    internal sealed class AllowNullAttribute : Attribute
+    { }
+
+    /// <summary>Specifies that null is disallowed as an input even if the corresponding type allows it.</summary>
+    [AttributeUsage(AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.Property, Inherited = false)]
+    internal sealed class DisallowNullAttribute : Attribute
+    { }
+
+    /// <summary>Specifies that an output may be null even if the corresponding type disallows it.</summary>
+    [AttributeUsage(AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.Property | AttributeTargets.ReturnValue, Inherited = false)]
+    internal sealed class MaybeNullAttribute : Attribute
+    { }
+
+    /// <summary>Specifies that an output will not be null even if the corresponding type allows it.</summary>
+    [AttributeUsage(AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.Property | AttributeTargets.ReturnValue, Inherited = false)]
+    internal sealed class NotNullAttribute : Attribute
+    { }
+
+    /// <summary>Specifies that when a method returns <see cref="ReturnValue"/>, the parameter may be null even if the corresponding type disallows it.</summary>
+    [AttributeUsage(AttributeTargets.Parameter, Inherited = false)]
+    internal sealed class MaybeNullWhenAttribute : Attribute
+    {
+        /// <summary>Initializes the attribute with the specified return value condition.</summary>
+        /// <param name="returnValue">
+        /// The return value condition. If the method returns this value, the associated parameter may be null.
+        /// </param>
+        public MaybeNullWhenAttribute(bool returnValue) => ReturnValue = returnValue;
+
+        /// <summary>Gets the return value condition.</summary>
+        public bool ReturnValue { get; }
+    }
+
+    /// <summary>Specifies that when a method returns <see cref="ReturnValue"/>, the parameter will not be null even if the corresponding type allows it.</summary>
+    [AttributeUsage(AttributeTargets.Parameter, Inherited = false)]
+    internal sealed class NotNullWhenAttribute : Attribute
+    {
+        /// <summary>Initializes the attribute with the specified return value condition.</summary>
+        /// <param name="returnValue">
+        /// The return value condition. If the method returns this value, the associated parameter will not be null.
+        /// </param>
+        public NotNullWhenAttribute(bool returnValue) => ReturnValue = returnValue;
+
+        /// <summary>Gets the return value condition.</summary>
+        public bool ReturnValue { get; }
+    }
+
+    /// <summary>Specifies that the output will be non-null if the named parameter is non-null.</summary>
+    [AttributeUsage(AttributeTargets.Parameter | AttributeTargets.Property | AttributeTargets.ReturnValue, AllowMultiple = true, Inherited = false)]
+    internal sealed class NotNullIfNotNullAttribute : Attribute
+    {
+        /// <summary>Initializes the attribute with the associated parameter name.</summary>
+        /// <param name="parameterName">
+        /// The associated parameter name.  The output will be non-null if the argument to the parameter specified is non-null.
+        /// </param>
+        public NotNullIfNotNullAttribute(string parameterName) => ParameterName = parameterName;
+
+        /// <summary>Gets the associated parameter name.</summary>
+        public string ParameterName { get; }
+    }
+
+    /// <summary>Applied to a method that will never return under any circumstance.</summary>
+    [AttributeUsage(AttributeTargets.Method, Inherited = false)]
+    internal sealed class DoesNotReturnAttribute : Attribute
+    { }
+
+    /// <summary>Specifies that the method will not return if the associated Boolean parameter is passed the specified value.</summary>
+    [AttributeUsage(AttributeTargets.Parameter, Inherited = false)]
+    internal sealed class DoesNotReturnIfAttribute : Attribute
+    {
+        /// <summary>Initializes the attribute with the specified parameter value.</summary>
+        /// <param name="parameterValue">
+        /// The condition parameter value. Code after the method will be considered unreachable by diagnostics if the argument to
+        /// the associated parameter matches this value.
+        /// </param>
+        public DoesNotReturnIfAttribute(bool parameterValue) => ParameterValue = parameterValue;
+
+        /// <summary>Gets the condition parameter value.</summary>
+        public bool ParameterValue { get; }
+    }
+}
+
+#endif

src/NetMQ/AsyncReceiveExtensions.cs

@@ -1,11 +1,11 @@
-#if NETSTANDARD2_0 || NETSTANDARD2_1 || NET47
+#nullable enable
+#if NETSTANDARD2_0 || NETSTANDARD2_1 || NET47
 
 using System;
 using System.Collections.Generic;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
-using JetBrains.Annotations;
 
 namespace NetMQ
 {
@@ -33,7 +33,7 @@ public static class AsyncReceiveExtensions
         /// <param name="cancellationToken">The token used to propagate notification that this operation should be canceled.</param>
         /// <returns>The content of the received message.</returns>
         public static async Task<NetMQMessage> ReceiveMultipartMessageAsync(
-            [NotNull] this NetMQSocket socket, 
+            this NetMQSocket socket, 
             int expectedFrameCount = 4,
             CancellationToken cancellationToken = default(CancellationToken))
         {
@@ -63,9 +63,8 @@ public static async Task<NetMQMessage> ReceiveMultipartMessageAsync(
         /// <param name="socket">The socket to receive from.</param>
         /// <param name="cancellationToken">The token used to propagate notification that this operation should be canceled.</param>
         /// <returns>The content of the received message frame and boolean indicate if another frame of the same message follows.</returns>
-        [NotNull]
         public static Task<(byte[], bool)> ReceiveFrameBytesAsync(
-            [NotNull] this NetMQSocket socket, 
+            this NetMQSocket socket, 
             CancellationToken cancellationToken = default(CancellationToken)
         )
         {
@@ -117,9 +116,8 @@ void Listener(object sender, NetMQSocketEventArgs args)
         /// <param name="socket">The socket to receive from.</param>
         /// <param name="cancellationToken">The token used to propagate notification that this operation should be canceled.</param>
         /// <returns>The content of the received message frame as a string and a boolean indicate if another frame of the same message follows.</returns>
-        [NotNull]
         public static Task<(string, bool)> ReceiveFrameStringAsync(
-            [NotNull] this NetMQSocket socket,
+            this NetMQSocket socket,
             CancellationToken cancellationToken = default(CancellationToken)
         )
         {
@@ -134,10 +132,9 @@ void Listener(object sender, NetMQSocketEventArgs args)
         /// <param name="encoding">The encoding used to convert the frame's data to a string.</param>
         /// <param name="cancellationToken">The token used to propagate notification that this operation should be canceled.</param>
         /// <returns>The content of the received message frame as a string and boolean indicate if another frame of the same message follows..</returns>
-        [NotNull]
         public static Task<(string, bool)> ReceiveFrameStringAsync(
-            [NotNull] this NetMQSocket socket, 
-            [NotNull] Encoding encoding,
+            this NetMQSocket socket, 
+            Encoding encoding,
             CancellationToken cancellationToken = default(CancellationToken))
         {
             if (NetMQRuntime.Current == null)
@@ -190,7 +187,7 @@ void Listener(object sender, NetMQSocketEventArgs args)
         /// </summary>
         /// <param name="socket">The socket to receive from.</param>
         /// <returns>Boolean indicate if another frame of the same message follows</returns>
-        public static Task<bool> SkipFrameAsync([NotNull] this NetMQSocket socket)
+        public static Task<bool> SkipFrameAsync(this NetMQSocket socket)
         {
             if (NetMQRuntime.Current == null)
                 throw new InvalidOperationException("NetMQRuntime must be created before calling async functions");
@@ -235,7 +232,7 @@ void Listener(object sender, NetMQSocketEventArgs args)
         /// Receive all frames of the next message from <paramref name="socket"/>, asynchronously, then ignore their contents.
         /// </summary>
         /// <param name="socket">The socket to receive from.</param>
-        public static async Task SkipMultipartMessageAsync([NotNull] this NetMQSocket socket)
+        public static async Task SkipMultipartMessageAsync(this NetMQSocket socket)
         {
             while (true)
             {
@@ -256,7 +253,7 @@ public static async Task SkipMultipartMessageAsync([NotNull] this NetMQSocket so
         /// <param name="socket">The socket to receive from.</param>
         /// <returns>The routing key and a boolean indicate if another frame of the same message follows.</returns>
 
-        public static async Task<(RoutingKey, bool)> ReceiveRoutingKeyAsync([NotNull] this NetMQSocket socket)
+        public static async Task<(RoutingKey, bool)> ReceiveRoutingKeyAsync(this NetMQSocket socket)
         {
             var (bytes, more) = await socket.ReceiveFrameBytesAsync();
 

src/NetMQ/AtomicCounterPool.cs

@@ -1,4 +1,5 @@
-using JetBrains.Annotations;
+#nullable enable
+
 using NetMQ.Core.Utils;
 using System;
 using System.Threading;
@@ -15,14 +16,13 @@ public interface IAtomicCounterPool : IDisposable
         /// Take an AtomicCounter from the pool.
         /// </summary>
         /// <returns>an atomic counter</returns>
-        [NotNull]
         AtomicCounter Take();
 
         /// <summary>
         /// Return the given atomic counter to the common pool.
         /// </summary>
         /// <param name="counter">the atomic counter to return to the buffer-pool</param>
-        void Return([NotNull] AtomicCounter counter);
+        void Return(AtomicCounter counter);
     }
 
     /// <summary>
@@ -99,7 +99,7 @@ public static void SetGCCounterPool()
         /// Set BufferPool to use the specified IAtomicCounterPool implementation to manage the pool.
         /// </summary>
         /// <param name="counterPool">the implementation of <see cref="IAtomicCounterPool"/> to use</param>
-        public static void SetCustomCounterPool([NotNull] IAtomicCounterPool counterPool)
+        public static void SetCustomCounterPool(IAtomicCounterPool counterPool)
         {
             var prior = Interlocked.Exchange(ref s_counterPool, counterPool);
 
@@ -110,7 +110,6 @@ public static void SetCustomCounterPool([NotNull] IAtomicCounterPool counterPool
         /// Allocate an atomic counter from the current <see cref="IAtomicCounterPool"/>.
         /// </summary>
         /// <returns>an atomic counter</returns>
-        [NotNull]
         public static AtomicCounter Take()
         {
             return s_counterPool.Take();
@@ -120,7 +119,7 @@ public static AtomicCounter Take()
         /// Returns <paramref name="counter"/> to the <see cref="IAtomicCounterPool"/>.
         /// </summary>
         /// <param name="counter">The atomic counter to be returned to the pool.</param>
-        public static void Return([NotNull] AtomicCounter counter)
+        public static void Return(AtomicCounter counter)
         {
             s_counterPool.Return(counter);
         }

src/NetMQ/BufferPool.cs

@@ -1,7 +1,8 @@
+#nullable enable
+
 using System;
 using System.ServiceModel.Channels;
 using System.Threading;
-using JetBrains.Annotations;
 
 namespace NetMQ
 {    
@@ -16,14 +17,13 @@ public interface IBufferPool : IDisposable
         /// </summary>
         /// <param name="size">the number of bytes to take</param>
         /// <returns>a byte-array that comes from the buffer-pool</returns>
-        [NotNull]
         byte[] Take(int size);
 
         /// <summary>
         /// Return the given byte-array buffer to the common buffer-pool.
         /// </summary>
         /// <param name="buffer">the byte-array to return to the buffer-pool</param>
-        void Return([NotNull] byte[] buffer);
+        void Return(byte[] buffer);
     }
 
     /// <summary>
@@ -180,7 +180,7 @@ public static void SetBufferManagerBufferPool(long maxBufferPoolSize, int maxBuf
         /// Set BufferPool to use the specified IBufferPool implementation to manage the buffer-pool.
         /// </summary>
         /// <param name="bufferPool">the implementation of <see cref="IBufferPool"/> to use</param>
-        public static void SetCustomBufferPool([NotNull] IBufferPool bufferPool)
+        public static void SetCustomBufferPool(IBufferPool bufferPool)
         {
             var prior = Interlocked.Exchange(ref s_bufferPool, bufferPool);
 
@@ -192,7 +192,6 @@ public static void SetCustomBufferPool([NotNull] IBufferPool bufferPool)
         /// </summary>
         /// <param name="size">The minimum size required, in bytes.</param>
         /// <returns>A byte array having at least <paramref name="size"/> bytes.</returns>
-        [NotNull]
         public static byte[] Take(int size)
         {
             return s_bufferPool.Take(size);
@@ -202,7 +201,7 @@ public static byte[] Take(int size)
         /// Returns <paramref name="buffer"/> to the <see cref="IBufferPool"/>.
         /// </summary>
         /// <param name="buffer">The byte array to be returned to the pool.</param>
-        public static void Return([NotNull] byte[] buffer)
+        public static void Return(byte[] buffer)
         {
             s_bufferPool.Return(buffer);
         }

src/NetMQ/EmptyArray.cs

@@ -1,3 +1,5 @@
+#nullable enable
+
 namespace NetMQ
 {
     internal static class EmptyArray<T>

src/NetMQ/Endianness.cs

@@ -1,4 +1,6 @@
-namespace NetMQ
+#nullable enable
+
+namespace NetMQ
 {
     /// <summary>
     /// This enum-type specifies either big-endian (Big) or little-endian (Little),

src/NetMQ/ErrorCode.cs

@@ -1,3 +1,5 @@
+#nullable enable
+
 namespace NetMQ
 {
     /// <summary>

src/NetMQ/EventDelegator.cs

@@ -1,6 +1,7 @@
-using System;
+#nullable enable
+
+using System;
 using System.Threading;
-using JetBrains.Annotations;
 
 namespace NetMQ
 {
@@ -16,15 +17,15 @@ internal class EventDelegator<T> : IDisposable where T : EventArgs
     {
         private readonly Action m_registerToEvent;
         private readonly Action m_unregisterFromEvent;
-        private EventHandler<T> m_event;
+        private EventHandler<T>? m_event;
         private int m_counter;
 
         /// <summary>
         /// Initialises a new instance.
         /// </summary>
         /// <param name="registerToEvent">an Action to perform when the first handler is registered for the event</param>
         /// <param name="unregisterFromEvent">an Action to perform when the last handler is unregistered from the event</param>
-        public EventDelegator([NotNull] Action registerToEvent, [NotNull] Action unregisterFromEvent)
+        public EventDelegator(Action registerToEvent, Action unregisterFromEvent)
         {
             m_registerToEvent = registerToEvent;
             m_unregisterFromEvent = unregisterFromEvent;
@@ -53,7 +54,7 @@ public event EventHandler<T> Event
         /// </summary>
         /// <param name="sender">the sender that the event-handler that gets notified of this event will receive</param>
         /// <param name="args">the subclass of EventArgs that the event-handler will receive</param>
-        public void Fire([NotNull] object sender, [NotNull] T args)
+        public void Fire(object sender, T args)
         {
             m_event?.Invoke(sender, args);
         }

src/NetMQ/INetMQPoller.cs

@@ -1,3 +1,5 @@
+#nullable enable
+
 using System;
 
 namespace NetMQ