wip

2026-08-20 04:42:57 +00:00 · 2019-10-20 13:36:38 +02:00
parent 8ec902951d
commit b2b5b0fef0
28 changed files with 819 additions and 237 deletions
@@ -0,0 +1,210 @@
+#if !NETSTANDARD2_1
+namespace System.Diagnostics.CodeAnalysis
+{
+    using global::System;
+
+    /// <summary>
+    ///     Specifies that <see langword="null"/> is allowed as an input even if the
+    ///     corresponding type disallows it.
+    /// </summary>
+    [AttributeUsage(
+        AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.Property,
+        Inherited = false
+    )]
+    [ExcludeFromCodeCoverage]
+    internal sealed class AllowNullAttribute : Attribute
+    {
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="AllowNullAttribute"/> class.
+        /// </summary>
+        public AllowNullAttribute() { }
+    }
+
+    /// <summary>
+    ///     Specifies that <see langword="null"/> is disallowed as an input even if the
+    ///     corresponding type allows it.
+    /// </summary>
+    [AttributeUsage(
+        AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.Property,
+        Inherited = false
+    )]
+
+    [ExcludeFromCodeCoverage]
+    internal sealed class DisallowNullAttribute : Attribute
+    {
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="DisallowNullAttribute"/> class.
+        /// </summary>
+        public DisallowNullAttribute() { }
+    }
+
+    /// <summary>
+    ///     Specifies that a method that will never return under any circumstance.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Method, Inherited = false)]
+    [ExcludeFromCodeCoverage]
+    internal sealed class DoesNotReturnAttribute : Attribute
+    {
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="DoesNotReturnAttribute"/> class.
+        /// </summary>
+        public DoesNotReturnAttribute() { }
+    }
+
+    /// <summary>
+    ///     Specifies that the method will not return if the associated <see cref="Boolean"/>
+    ///     parameter is passed the specified value.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Parameter, Inherited = false)]
+    [ExcludeFromCodeCoverage]
+    internal sealed class DoesNotReturnIfAttribute : Attribute
+    {
+        /// <summary>
+        ///     Gets the condition parameter value.
+        ///     Code after the method is considered unreachable by diagnostics if the argument
+        ///     to the associated parameter matches this value.
+        /// </summary>
+        public bool ParameterValue { get; }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="DoesNotReturnIfAttribute"/>
+        ///     class with the specified parameter value.
+        /// </summary>
+        /// <param name="parameterValue">
+        ///     The condition parameter value.
+        ///     Code after the method is considered unreachable by diagnostics if the argument
+        ///     to the associated parameter matches this value.
+        /// </param>
+        public DoesNotReturnIfAttribute(bool parameterValue)
+        {
+            ParameterValue = parameterValue;
+        }
+    }
+
+    /// <summary>
+    ///     Specifies that an output may be <see langword="null"/> even if the
+    ///     corresponding type disallows it.
+    /// </summary>
+    [AttributeUsage(
+        AttributeTargets.Field | AttributeTargets.Parameter |
+        AttributeTargets.Property | AttributeTargets.ReturnValue,
+        Inherited = false
+    )]
+    [ExcludeFromCodeCoverage]
+    internal sealed class MaybeNullAttribute : Attribute
+    {
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="MaybeNullAttribute"/> class.
+        /// </summary>
+        public MaybeNullAttribute() { }
+    }
+
+    /// <summary>
+    ///     Specifies that when a method returns <see cref="ReturnValue"/>, 
+    ///     the parameter may be <see langword="null"/> even if the corresponding type disallows it.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Parameter, Inherited = false)]
+    [ExcludeFromCodeCoverage]
+    internal sealed class MaybeNullWhenAttribute : Attribute
+    {
+        /// <summary>
+        ///     Gets the return value condition.
+        ///     If the method returns this value, the associated parameter may be <see langword="null"/>.
+        /// </summary>
+        public bool ReturnValue { get; }
+
+        /// <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 <see langword="null"/>.
+        /// </param>
+        public MaybeNullWhenAttribute(bool returnValue)
+        {
+            ReturnValue = returnValue;
+        }
+    }
+
+    /// <summary>
+    ///     Specifies that an output is not <see langword="null"/> even if the
+    ///     corresponding type allows it.
+    /// </summary>
+    [AttributeUsage(
+        AttributeTargets.Field | AttributeTargets.Parameter |
+        AttributeTargets.Property | AttributeTargets.ReturnValue,
+        Inherited = false
+    )]
+    [ExcludeFromCodeCoverage]
+    internal sealed class NotNullAttribute : Attribute
+    {
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="NotNullAttribute"/> class.
+        /// </summary>
+        public NotNullAttribute() { }
+    }
+
+    /// <summary>
+    ///     Specifies that the output will be non-<see langword="null"/> if the
+    ///     named parameter is non-<see langword="null"/>.
+    /// </summary>
+    [AttributeUsage(
+        AttributeTargets.Parameter | AttributeTargets.Property | AttributeTargets.ReturnValue,
+        AllowMultiple = true,
+        Inherited = false
+    )]
+    [ExcludeFromCodeCoverage]
+    internal sealed class NotNullIfNotNullAttribute : Attribute
+    {
+        /// <summary>
+        ///     Gets the associated parameter name.
+        ///     The output will be non-<see langword="null"/> if the argument to the
+        ///     parameter specified is non-<see langword="null"/>.
+        /// </summary>
+        public string ParameterName { get; }
+
+        /// <summary>
+        ///     Initializes the attribute with the associated parameter name.
+        /// </summary>
+        /// <param name="parameterName">
+        ///     The associated parameter name.
+        ///     The output will be non-<see langword="null"/> if the argument to the
+        ///     parameter specified is non-<see langword="null"/>.
+        /// </param>
+        public NotNullIfNotNullAttribute(string parameterName)
+        {
+            // .NET Core 3.0 doesn't throw an ArgumentNullException, even though this is
+            // tagged as non-null.
+            // Follow this behavior here.
+            ParameterName = parameterName;
+        }
+    }
+
+    /// <summary>
+    ///     Specifies that when a method returns <see cref="ReturnValue"/>,
+    ///     the parameter will not be <see langword="null"/> even if the corresponding type allows it.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Parameter, Inherited = false)]
+    [ExcludeFromCodeCoverage]
+    internal sealed class NotNullWhenAttribute : Attribute
+    {
+        /// <summary>
+        ///     Gets the return value condition.
+        ///     If the method returns this value, the associated parameter will not be <see langword="null"/>.
+        /// </summary>
+        public bool ReturnValue { get; }
+
+        /// <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 <see langword="null"/>.
+        /// </param>
+        public NotNullWhenAttribute(bool returnValue)
+        {
+            ReturnValue = returnValue;
+        }
+    }
+}
+#endif