Move async collection to core (Azure#7038)

sdk/core/Azure.Core/src/AsyncCollection.cs

@@ -0,0 +1,95 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Threading;
+
+namespace Azure
+{
+    /// <summary>
+    /// A collection of values that may take multiple service requests to
+    /// iterate over.
+    /// </summary>
+    /// <typeparam name="T">The type of the values.</typeparam>
+    public abstract class AsyncCollection<T> : IAsyncEnumerable<Response<T>>
+    {
+        /// <summary>
+        /// Gets a <see cref="CancellationToken"/> used for requests made while
+        /// enumerating asynchronously.
+        /// </summary>
+        protected virtual CancellationToken CancellationToken { get; }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="AsyncCollection{T}"/>
+        /// class for mocking.
+        /// </summary>
+        protected AsyncCollection() =>
+            this.CancellationToken = CancellationToken.None;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="AsyncCollection{T}"/>
+        /// class.
+        /// </summary>
+        /// <param name="cancellationToken">
+        /// The <see cref="CancellationToken"/> used for requests made while
+        /// enumerating asynchronously.
+        /// </param>
+        protected AsyncCollection(CancellationToken cancellationToken) =>
+            this.CancellationToken = cancellationToken;
+
+        /// <summary>
+        /// Enumerate the values a <see cref="Page{T}"/> at a time.  This may
+        /// make mutliple service requests.
+        /// </summary>
+        /// <param name="continuationToken">
+        /// A continuation token indicating where to resume paging or null to
+        /// begin paging from the beginning.
+        /// </param>
+        /// <param name="pageSizeHint">
+        /// The size of <see cref="Page{T}"/>s that should be requested (from
+        /// service operations that support it).
+        /// </param>
+        /// <returns>
+        /// An async sequence of <see cref="Page{T}"/>s.
+        /// </returns>
+        public abstract IAsyncEnumerable<Page<T>> ByPage(
+            string continuationToken = default,
+            int? pageSizeHint = default);
+
+        /// <summary>
+        /// Enumerate the values in the collection asynchronously.  This may
+        /// make mutliple service requests.
+        /// </summary>
+        /// <param name="cancellationToken">
+        /// The <see cref="CancellationToken"/> used for requests made while
+        /// enumerating asynchronously.
+        /// </param>
+        /// <returns>An async sequence of values.</returns>
+        public abstract IAsyncEnumerator<Response<T>> GetAsyncEnumerator(CancellationToken cancellationToken = default);
+
+        /// <summary>
+        /// Creates a string representation of an <see cref="AsyncCollection{T}"/>.
+        /// </summary>
+        /// <returns>
+        /// A string representation of an <see cref="AsyncCollection{T}"/>.
+        /// </returns>
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public override string ToString() => base.ToString();
+
+        /// <summary>
+        /// Check if two <see cref="AsyncCollection{T}"/> instances are equal.
+        /// </summary>
+        /// <param name="obj">The instance to compare to.</param>
+        /// <returns>True if they're equal, false otherwise.</returns>
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public override bool Equals(object obj) => base.Equals(obj);
+
+        /// <summary>
+        /// Get a hash code for the <see cref="AsyncCollection{T}"/>.
+        /// </summary>
+        /// <returns>Hash code for the <see cref="Page{T}"/>.</returns>
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public override int GetHashCode() => base.GetHashCode();
+    }
+}

sdk/core/Azure.Core/src/Page.cs

@@ -0,0 +1,82 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System.Collections.Generic;
+using System.ComponentModel;
+
+namespace Azure
+{
+    /// <summary>
+    /// A single <see cref="Page{T}"/> of values from a request that may return
+    /// zero or more <see cref="Page{T}"/>s of values.
+    /// </summary>
+    /// <typeparam name="T">The type of values.</typeparam>
+    public readonly struct Page<T>
+    {
+        /// <summary>
+        /// Gets the values in this <see cref="Page{T}"/>.
+        /// </summary>
+        public IReadOnlyList<T> Values { get; }
+
+        /// <summary>
+        /// Gets the continuation token used to request the next
+        /// <see cref="Page{T}"/>.  The continuation token may be null or
+        /// empty when there are no more pages.
+        /// </summary>
+        public string ContinuationToken { get; }
+
+        /// <summary>
+        /// The <see cref="Response"/> that provided this <see cref="Page{T}"/>.
+        /// </summary>
+        private readonly Response _response;
+
+        /// <summary>
+        /// Gets the <see cref="Response"/> that provided this
+        /// <see cref="Page{T}"/>.
+        /// </summary>
+        public Response GetRawResponse() => this._response;
+
+        /// <summary>
+        /// Creates a new <see cref="Page{T}"/>.
+        /// </summary>
+        /// <param name="values">
+        /// The values in this <see cref="Page{T}"/>.
+        /// </param>
+        /// <param name="continuationToken">
+        /// The continuation token used to request the next <see cref="Page{T}"/>.
+        /// </param>
+        /// <param name="response">
+        /// The <see cref="Response"/> that provided this <see cref="Page{T}"/>.
+        /// </param>
+        public Page(IReadOnlyList<T> values, string continuationToken, Response response)
+        {
+            this.Values = values;
+            this.ContinuationToken = continuationToken;
+            this._response = response;
+        }
+
+        /// <summary>
+        /// Creates a string representation of an <see cref="Page{T}"/>.
+        /// </summary>
+        /// <returns>
+        /// A string representation of an <see cref="Page{T}"/>.
+        /// </returns>
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public override string ToString() => base.ToString();
+
+        /// <summary>
+        /// Check if two <see cref="Page{T}"/> instances are equal.
+        /// </summary>
+        /// <param name="obj">The instance to compare to.</param>
+        /// <returns>True if they're equal, false otherwise.</returns>
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public override bool Equals(object obj) => base.Equals(obj);
+
+        /// <summary>
+        /// Get a hash code for the <see cref="Page{T}"/>.
+        /// </summary>
+        /// <returns>Hash code for the <see cref="Page{T}"/>.</returns>
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public override int GetHashCode() => base.GetHashCode();
+    }
+}

sdk/storage/Azure.Storage.Blobs/tests/ContainerClientTests.cs

@@ -1161,7 +1161,7 @@ public async Task ListBlobsFlatSegmentAsync_MaxResults()
                 var page = await container.GetBlobsAsync().ByPage(pageSizeHint: 2).FirstAsync();
 
                 // Assert
-                Assert.AreEqual(2, page.Values.Length);
+                Assert.AreEqual(2, page.Values.Count);
             }
         }
 
@@ -1365,7 +1365,7 @@ public async Task ListBlobsHierarchySegmentAsync_MaxResults()
                     .FirstAsync();
 
                 // Assert
-                Assert.AreEqual(2, page.Values.Length);
+                Assert.AreEqual(2, page.Values.Count);
             }
         }
 

sdk/storage/Azure.Storage.Common/src/StorageAsyncCollection.cs

@@ -138,7 +138,7 @@ public override async IAsyncEnumerator<Response<T>> GetAsyncEnumerator(Cancellat
         /// make mutliple service requests.
         /// </summary>
         /// <returns>A sequence of values.</returns>
-        protected override IEnumerator<Response<T>> GetEnumerator()
+        protected IEnumerator<Response<T>> GetEnumerator()
         {
             string continuationToken = null;
             do