Merge pull request #13 from rameel/cleanup

Cleanup and formatting

Author: rameel

Ramstack.Structures.Tests/Collections/ReadOnlyArrayTests.cs

@@ -583,6 +583,19 @@ public void Operator_Conversions(string? value)
         }
     }
 
+    [TestCase(0)]
+    [TestCase(1)]
+    [TestCase(9)]
+    public void Linq_ToList(int count)
+    {
+        var array = CreateArray(count).ToReadOnlyArray();
+        var list = array.ToList();
+
+        Assert.That(list.Count, Is.EqualTo(count));
+        Assert.That(list.Capacity, Is.EqualTo(count));
+        Assert.That(list, Is.EqualTo(array));
+    }
+
     private static int[] CreateArray(int length) =>
         Enumerable.Range(0, length).ToArray();
 }

Ramstack.Structures/Collections/ArrayViewExtensions.cs

@@ -148,7 +148,7 @@ public static ArrayView<T> AsView<T>(this List<T>? list)
     {
         if (list is not null)
         {
-            var array = ListAccessor<T>.GetBuffer(list);
+            var array = ListAccessor<T>.GetArray(list);
             var count = Math.Min(list.Count, array.Length);
 
             return new ArrayView<T>(array, 0, count);
@@ -157,26 +157,5 @@ public static ArrayView<T> AsView<T>(this List<T>? list)
         return ArrayView<T>.Empty;
     }
 
-    #region Inner type: ListAccessor<T>
-
-    /// <summary>
-    /// Provides low-level access to the internal array buffer of a <see cref="List{T}"/>.
-    /// </summary>
-    /// <typeparam name="T">The type of the elements in the list.</typeparam>
-    private static class ListAccessor<T>
-    {
-        /// <summary>
-        /// Retrieves a reference to the internal array buffer of the specified <see cref="List{T}"/>.
-        /// </summary>
-        /// <param name="list">The list whose internal buffer is to be accessed.</param>
-        /// <returns>
-        /// A reference to the internal array used by the list.
-        /// </returns>
-        [UnsafeAccessor(UnsafeAccessorKind.Field, Name = "_items")]
-        public static extern ref T[] GetBuffer(List<T> list);
-    }
-
-    #endregion
-
     #endif
 }

Ramstack.Structures/Collections/ArrayView`1.cs

@@ -1,8 +1,3 @@
-using System.Collections;
-using System.Collections.Immutable;
-
-using Ramstack.Internal;
-
 namespace Ramstack.Collections;
 
 /// <summary>
@@ -201,7 +196,28 @@ public ReadOnlyMemory<T> AsMemory() =>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public ref readonly T GetPinnableReference()
     {
-        // To match the behavior of ReadOnlySpan<T>
+        //
+        // Normalize the returned reference.
+        // We must not return a reference to an element outside the bounds of our view
+        // when the view is empty (_count = 0), even if it points to a valid element
+        // in the underlying array. In this case, we return a null reference.
+        //
+        // Examples:
+        //
+        // Full array (_array):
+        // [0][1][2][3][4][5][6][7][8][9]
+        //  |--------------------------|
+        //
+        // Case 1: Non-empty view (_index = 3, _count = 4)
+        //          [3][4][5][6]
+        //           ^        ^
+        //           |--------| <- valid range for this view
+        //
+        // Case 2: Empty view (_index = 3, _count = 0)
+        //          [3][4][5][6]
+        //           ^
+        //           | <- no valid reference for this view
+        //
 
         ref var p = ref Unsafe.NullRef<T>();
 
@@ -219,8 +235,9 @@ public void CopyTo(Span<T> destination) =>
         AsSpan().CopyTo(destination);
 
     /// <summary>
-    /// Attempts to copy the contents of this <see cref="ArrayView{T}"/> into a destination <see cref="Span{T}"/>
-    /// and returns a value to indicate whether the operation succeeded.
+    /// Attempts to copy the contents of this <see cref="ArrayView{T}"/>
+    /// into a destination <see cref="Span{T}"/> and returns a value to indicate
+    /// whether the operation succeeded.
     /// </summary>
     /// <param name="destination">The span to copy items into.</param>
     /// <returns>
@@ -302,7 +319,8 @@ public static implicit operator ArrayView<T>(ArraySegment<T> segment) =>
         new(segment.Array!, segment.Offset, segment.Count, dummy: 0);
 
     /// <summary>
-    /// Returns a string representation of the current instance's state, intended for debugging purposes.
+    /// Returns a string representation of the current instance's state,
+    /// intended for debugging purposes.
     /// </summary>
     /// <returns>
     /// A string containing information about the current instance.
@@ -363,9 +381,9 @@ public readonly ref readonly T Current
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         internal Enumerator(ArrayView<T> view)
         {
-            _array = view._array;
             _index = view._index - 1;
             _final = view._index + view._count;
+            _array = view._array;
         }
 
         /// <inheritdoc cref="IEnumerator.MoveNext" />
@@ -408,9 +426,9 @@ public T Current
         /// <param name="view">The <see cref="ArrayView{T}"/> to iterate through its elements.</param>
         public ArrayViewEnumerator(ArrayView<T> view)
         {
-            _array = view._array;
             _index = view._index - 1;
             _final = view._index + view._count;
+            _array = view._array;
         }
 
         /// <inheritdoc />

Ramstack.Structures/Collections/ImmutableArrayExtensions.cs

@@ -1,5 +1,3 @@
-using System.Collections.Immutable;
-
 namespace Ramstack.Collections;
 
 /// <summary>

Ramstack.Structures/Collections/ReadOnlyArrayExtensions.Linq.cs

@@ -392,15 +392,22 @@ public static T[] ToArray<T>(this ReadOnlyArray<T> source)
     /// <inheritdoc cref="Enumerable.ToList{TSource}"/>
     public static List<T> ToList<T>(this ReadOnlyArray<T> source)
     {
-        #if NET8_0_OR_GREATER
+        #if NET9_0_OR_GREATER
+        var list = new List<T>();
+
+        ListAccessor<T>.GetArray(list) = source.ToArray();
+        ListAccessor<T>.GetCount(list) = source.Length;
+
+        return list;
+        #elif NET8_0_OR_GREATER
         var list = new List<T>(source.Length);
 
         System.Runtime.InteropServices.CollectionsMarshal.SetCount(list, source.Length);
-        source.CopyTo(System.Runtime.InteropServices.CollectionsMarshal.AsSpan(list));
+        source.TryCopyTo(System.Runtime.InteropServices.CollectionsMarshal.AsSpan(list));
 
         return list;
         #else
-        return source.Inner!.ToList();
+        return [..source.Inner!];
         #endif
     }
 

Ramstack.Structures/Collections/ReadOnlyArrayExtensions.cs

@@ -1,5 +1,3 @@
-using System.Collections.Immutable;
-
 namespace Ramstack.Collections;
 
 /// <summary>
@@ -70,19 +68,22 @@ public static ReadOnlyArray<T> ToReadOnlyArray<T>([InstantHandle] this IEnumerab
     /// <param name="array">The <see cref="ReadOnlyArray{T}"/> instance.</param>
     /// <param name="value">The object to locate in array.</param>
     /// <returns>
-    /// The zero-based index of the first occurrence of <paramref name="value"/> in the <paramref name="array"/>, if found; otherwise, <c>-1</c>.
+    /// The zero-based index of the first occurrence of <paramref name="value"/>
+    /// in the <paramref name="array"/>, if found; otherwise, <c>-1</c>.
     /// </returns>
     public static int IndexOf<T>(this ReadOnlyArray<T> array, T value) =>
         Array.IndexOf(array.Inner!, value);
 
     /// <summary>
-    /// Searches for the specified object and returns the index of the last occurrence within the entire <see cref="ReadOnlyArray{T}"/>.
+    /// Searches for the specified object and returns the index
+    /// of the last occurrence within the entire <see cref="ReadOnlyArray{T}"/>.
     /// </summary>
     /// <typeparam name="T">The type of element in the array.</typeparam>
     /// <param name="array">The <see cref="ReadOnlyArray{T}"/> instance.</param>
     /// <param name="value">The object to locate in array.</param>
     /// <returns>
-    /// The zero-based index of the last occurrence of <paramref name="value"/> in the <paramref name="array"/>, if found; otherwise, <c>-1</c>.
+    /// The zero-based index of the last occurrence of <paramref name="value"/>
+    /// in the <paramref name="array"/>, if found; otherwise, <c>-1</c>.
     /// </returns>
     public static int LastIndexOf<T>(this ReadOnlyArray<T> array, T value) =>
         Array.LastIndexOf(array.Inner!, value);

Ramstack.Structures/Collections/ReadOnlyArray`1.cs

@@ -1,6 +1,3 @@
-using System.Collections;
-using System.Collections.Immutable;
-
 namespace Ramstack.Collections;
 
 /// <summary>
@@ -102,7 +99,8 @@ public ReadOnlyArray(T item1, T item2, T item3, T item4) =>
     public ReadOnlyArray(ReadOnlySpan<T> items)
     {
         //
-        // Avoid address exposure in cases where the destination local does not actually end up escaping in any way.
+        // Avoid address exposure in cases where the destination local
+        // does not actually end up escaping in any way.
         // https://github.com/dotnet/runtime/pull/102808
         //
 
@@ -133,7 +131,8 @@ public Enumerator GetEnumerator()
     /// </summary>
     /// <param name="start">The index at which to begin the slice.</param>
     /// <returns>
-    /// A readonly span that consists of all elements of the current array from <paramref name="start"/> to the end.
+    /// A readonly span that consists of all elements of the current array
+    /// from <paramref name="start"/> to the end.
     /// </returns>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public ReadOnlyArray<T> Slice(int start)
@@ -152,7 +151,8 @@ public ReadOnlyArray<T> Slice(int start)
     /// <param name="start">The index at which to begin the slice.</param>
     /// <param name="length">The desired length for the slice.</param>
     /// <returns>
-    /// A readonly span that consists of <paramref name="length"/> elements from the current array starting at <paramref name="start"/>.
+    /// A readonly span that consists of <paramref name="length"/> elements
+    /// from the current array starting at <paramref name="start"/>.
     /// </returns>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public ReadOnlyArray<T> Slice(int start, int length)
@@ -188,7 +188,8 @@ public ReadOnlySpan<T> AsSpan() =>
         new(Inner ?? []);
 
     /// <summary>
-    /// Creates a new read-only span over a portion of the current array starting at a specified position to the end of the array.
+    /// Creates a new read-only span over a portion of the current array
+    /// starting at a specified position to the end of the array.
     /// </summary>
     /// <param name="start">The index at which to begin the span.</param>
     /// <returns>
@@ -199,7 +200,8 @@ public ReadOnlySpan<T> AsSpan(int start) =>
         AsSpan().Slice(start);
 
     /// <summary>
-    /// Creates a new read-only span over a portion of the current array starting at a specified position for a specified length.
+    /// Creates a new read-only span over a portion of the current array
+    /// starting at a specified position for a specified length.
     /// </summary>
     /// <param name="start">The index at which to begin the span.</param>
     /// <param name="length">The number of items in the span.</param>
@@ -219,7 +221,8 @@ public ArrayView<T> AsView() =>
         new(Inner ?? []);
 
     /// <summary>
-    /// Creates an <see cref="ArrayView{T}"/> over the current array starting at a specified position to the end of the array.
+    /// Creates an <see cref="ArrayView{T}"/> over the current array
+    /// starting at a specified position to the end of the array.
     /// </summary>
     /// <param name="index">The index at which to begin the array view.</param>
     /// <returns>
@@ -230,7 +233,8 @@ public ArrayView<T> AsView(int index) =>
         AsView().Slice(index);
 
     /// <summary>
-    /// Creates an <see cref="ArrayView{T}"/> over the current array starting at a specified position for a specified length.
+    /// Creates an <see cref="ArrayView{T}"/> over the current array
+    /// starting at a specified position for a specified length.
     /// </summary>
     /// <param name="index">The index at which to begin the array view.</param>
     /// <param name="count">The number of items in the array view.</param>
@@ -253,7 +257,8 @@ public ReadOnlyMemory<T> AsMemory() =>
     /// Returns a reference to the element of the <see cref="ReadOnlyArray{T}"/> at index zero.
     /// </summary>
     /// <returns>
-    /// A reference to the element of the <see cref="ReadOnlyArray{T}"/> at index zero, or <see langword="null"/> if <see cref="IsDefault"/> is true.
+    /// A reference to the element of the <see cref="ReadOnlyArray{T}"/> at index zero,
+    /// or <see langword="null"/> if <see cref="IsDefault"/> is true.
     /// </returns>
     public ref readonly T GetPinnableReference() =>
         ref MemoryMarshal.GetArrayDataReference(Inner!);
@@ -492,15 +497,16 @@ public readonly ref readonly T Current
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         internal Enumerator(T[] array)
         {
-            _array = array;
             _index = -1;
+            _array = array;
         }
 
         /// <summary>
         /// Advances the enumerator to the next element of the collection.
         /// </summary>
         /// <returns>
-        /// <see langword="true"/> if the enumerator was successfully advanced to the next element; otherwise, <see langword="false"/>.
+        /// <see langword="true"/> if the enumerator was successfully advanced to the next element;
+        /// otherwise, <see langword="false"/>.
         /// </returns>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public bool MoveNext() =>

Ramstack.Structures/Internal/Jetbrains.Assertions.cs

@@ -46,6 +46,7 @@ namespace JetBrains.Annotations;
 /// If <see cref="RequireAwait"/> is true, the attribute will only take effect if the method invocation is located under the 'await' expression.
 /// </summary>
 [AttributeUsage(AttributeTargets.Parameter)]
+[Conditional("JETBRAINS_ANNOTATIONS")]
 internal sealed class InstantHandleAttribute : Attribute
 {
     /// <summary>
@@ -61,4 +62,5 @@ internal sealed class InstantHandleAttribute : Attribute
 /// of delegate type by analyzing LINQ method chains.
 /// </summary>
 [AttributeUsage(AttributeTargets.Method)]
+[Conditional("JETBRAINS_ANNOTATIONS")]
 internal sealed class LinqTunnelAttribute : Attribute { }

Ramstack.Structures/Internal/ListAccessor.cs

@@ -0,0 +1,33 @@
+namespace Ramstack.Internal;
+
+#if NET9_0_OR_GREATER
+
+/// <summary>
+/// Provides low-level access to the internal array buffer of a <see cref="List{T}"/>.
+/// </summary>
+/// <typeparam name="T">The type of the elements in the list.</typeparam>
+internal static class ListAccessor<T>
+{
+    /// <summary>
+    /// Returns a reference to the internal array buffer of the specified <see cref="List{T}"/>.
+    /// </summary>
+    /// <param name="list">The list whose internal buffer is to be accessed.</param>
+    /// <returns>
+    /// A reference to the internal array used by the list.
+    /// </returns>
+    [UnsafeAccessor(UnsafeAccessorKind.Field, Name = "_items")]
+    public static extern ref T[] GetArray(List<T> list);
+
+    /// <summary>
+    /// Returns a reference to the internal "_size" field of the specified <see cref="List{T}"/>
+    /// representing the number of elements in the list.
+    /// </summary>
+    /// <param name="list">The list whose internal "_size" field is to be accessed.</param>
+    /// <returns>
+    /// A reference to the internal "_size" field representing the number of elements in the list.
+    /// </returns>
+    [UnsafeAccessor(UnsafeAccessorKind.Field, Name = "_size")]
+    public static extern ref int GetCount(List<T> list);
+}
+
+#endif

Ramstack.Structures/Ramstack.Structures.csproj

@@ -40,13 +40,17 @@ Ramstack.Collections.ReadOnlyArray&lt;T&gt;</Description>
   </PropertyGroup>
 
   <ItemGroup>
+    <Using Include="JetBrains.Annotations" />
+    <Using Include="Ramstack.Internal" />
+    <Using Include="System.Collections" />
+    <Using Include="System.Collections.Generic" />
+    <Using Include="System.Collections.Immutable" />
     <Using Include="System.ComponentModel" />
     <Using Include="System.Diagnostics" />
     <Using Include="System.Diagnostics.CodeAnalysis" />
     <Using Include="System.Globalization" />
     <Using Include="System.Runtime.CompilerServices" />
     <Using Include="System.Runtime.InteropServices" />
-    <Using Include="JetBrains.Annotations" />
   </ItemGroup>
 
   <ItemGroup>