Align total count on connection & collection segment (#4960)

src/HotChocolate/Core/src/Types.CursorPagination/Connection.cs

@@ -5,10 +5,25 @@
 
 namespace HotChocolate.Types.Pagination;
 
+/// <summary>
+/// The connection represents one section of a dataset / collection.
+/// </summary>
 public class Connection : IPage
 {
     private readonly Func<CancellationToken, ValueTask<int>> _getTotalCount;
 
+    /// <summary>
+    /// Initializes <see cref="Connection" />.
+    /// </summary>
+    /// <param name="edges">
+    /// The edges that belong to this connection.
+    /// </param>
+    /// <param name="info">
+    /// Additional information about this connection.
+    /// </param>
+    /// <param name="getTotalCount">
+    /// A delegate to request the the total count.
+    /// </param>
     public Connection(
         IReadOnlyCollection<IEdge> edges,
         ConnectionPageInfo info,
@@ -22,15 +37,59 @@ public class Connection : IPage
             throw new ArgumentNullException(nameof(info));
     }
 
+    /// <summary>
+    /// Initializes <see cref="Connection" />.
+    /// </summary>
+    /// <param name="edges">
+    /// The edges that belong to this connection.
+    /// </param>
+    /// <param name="info">
+    /// Additional information about this connection.
+    /// </param>
+    /// <param name="totalCount">
+    /// The total count of items of this connection
+    /// </param>
+    public Connection(
+        IReadOnlyCollection<IEdge> edges,
+        ConnectionPageInfo info,
+        int totalCount = 0)
+    {
+        _getTotalCount = _ => new(totalCount);
+        Edges = edges ??
+            throw new ArgumentNullException(nameof(edges));
+        Info = info ??
+            throw new ArgumentNullException(nameof(info));
+    }
+
+    /// <summary>
+    /// The edges that belong to this connection.
+    /// </summary>
     public IReadOnlyCollection<IEdge> Edges { get; }
 
+    /// <summary>
+    /// The items that belong to this connection.
+    /// </summary>
     IReadOnlyCollection<object> IPage.Items => Edges;
 
+    /// <summary>
+    /// Information about pagination in a connection.
+    /// </summary>
     public ConnectionPageInfo Info { get; }
 
+    /// <summary>
+    /// Information about pagination in a connection.
+    /// </summary>
     IPageInfo IPage.Info => Info;
 
-    public ValueTask<int> GetTotalCountAsync(
-        CancellationToken cancellationToken) =>
+    /// <summary>
+    /// Requests the total count of the data set / collection that is being paged.
+    /// </summary>
+    /// <param name="cancellationToken">
+    /// The cancellation token.
+    /// </param>
+    /// <returns>
+    /// The total count of the data set / collection.
+    /// </returns>
+    public ValueTask<int> GetTotalCountAsync(CancellationToken cancellationToken) =>
         _getTotalCount(cancellationToken);
 }

src/HotChocolate/Core/src/Types.CursorPagination/ConnectionPageInfo.cs

@@ -1,28 +1,49 @@
 namespace HotChocolate.Types.Pagination;
 
+/// <summary>
+/// Represents the connection paging page info.
+/// This class provides additional information about pagination in a connection.
+/// </summary>
 public class ConnectionPageInfo : IPageInfo
 {
+    /// <summary>
+    /// Initializes <see cref="ConnectionPageInfo" />.
+    /// </summary>
+    /// <param name="hasNextPage"></param>
+    /// <param name="hasPreviousPage"></param>
+    /// <param name="startCursor"></param>
+    /// <param name="endCursor"></param>
     public ConnectionPageInfo(
         bool hasNextPage,
         bool hasPreviousPage,
         string? startCursor,
-        string? endCursor,
-        int? totalCount = null)
+        string? endCursor)
     {
         HasNextPage = hasNextPage;
         HasPreviousPage = hasPreviousPage;
         StartCursor = startCursor;
         EndCursor = endCursor;
-        TotalCount = totalCount;
     }
 
+    /// <summary>
+    /// <c>true</c> if there is another page after the current one.
+    /// <c>false</c> if this page is the last page of the current data set / collection.
+    /// </summary>
     public bool HasNextPage { get; }
 
+    /// <summary>
+    /// <c>true</c> if there is before this page.
+    /// <c>false</c> if this page is the first page in the current data set / collection.
+    /// </summary>
     public bool HasPreviousPage { get; }
 
+    /// <summary>
+    /// When paginating backwards, the cursor to continue.
+    /// </summary>
     public string? StartCursor { get; }
 
+    /// <summary>
+    /// When paginating forwards, the cursor to continue.
+    /// </summary>
     public string? EndCursor { get; }
-
-    public int? TotalCount { get; }
 }

src/HotChocolate/Core/src/Types.CursorPagination/Connection~1.cs

@@ -5,8 +5,23 @@
 
 namespace HotChocolate.Types.Pagination;
 
+/// <summary>
+/// The connection represents one section of a dataset / collection.
+/// </summary>
 public class Connection<T> : Connection
 {
+    /// <summary>
+    /// Initializes <see cref="Connection{T}" />.
+    /// </summary>
+    /// <param name="edges">
+    /// The edges that belong to this connection.
+    /// </param>
+    /// <param name="info">
+    /// Additional information about this connection.
+    /// </param>
+    /// <param name="getTotalCount">
+    /// A delegate to request the the total count.
+    /// </param>
     public Connection(
         IReadOnlyCollection<Edge<T>> edges,
         ConnectionPageInfo info,
@@ -16,5 +31,29 @@ public class Connection<T> : Connection
         Edges = edges;
     }
 
+    /// <summary>
+    /// Initializes <see cref="Connection{T}" />.
+    /// </summary>
+    /// <param name="edges">
+    /// The edges that belong to this connection.
+    /// </param>
+    /// <param name="info">
+    /// Additional information about this connection.
+    /// </param>
+    /// <param name="totalCount">
+    /// The total count of items of this connection
+    /// </param>
+    public Connection(
+        IReadOnlyCollection<Edge<T>> edges,
+        ConnectionPageInfo info,
+        int totalCount = 0)
+        : base(edges, info, totalCount)
+    {
+        Edges = edges;
+    }
+
+    /// <summary>
+    /// The edges that belong to this connection.
+    /// </summary>
     public new IReadOnlyCollection<Edge<T>> Edges { get; }
 }

src/HotChocolate/Core/src/Types.CursorPagination/CursorPaginationAlgorithm.cs

@@ -57,8 +57,8 @@ public abstract class CursorPaginationAlgorithm<TQuery, TEntity> where TQuery :
         }
 
         var maxElementCount = int.MaxValue;
-        Func<CancellationToken, ValueTask<int>> executeCount = totalCount is null ?
-            ct => CountAsync(query, ct)
+        Func<CancellationToken, ValueTask<int>> executeCount = totalCount is null
+            ? ct => CountAsync(query, ct)
             : _ => new ValueTask<int>(totalCount.Value);
 
         // We only need the maximal element count if no `before` counter is set and no `first`
@@ -68,9 +68,9 @@ public abstract class CursorPaginationAlgorithm<TQuery, TEntity> where TQuery :
             var count = await executeCount(cancellationToken);
             maxElementCount = count;
 
-            // in case we already know the total count, we override the countAsync parameter
-            // so that we do not have to fetch the count twice
-            executeCount = _ => new ValueTask<int>(count);
+            // in case we already know the total count, we set the totalCount parameter
+            // so that we do not have have to fetch the count twice
+            executeCount = _ => new(count);
         }
 
         CursorPagingRange range = SliceRange(arguments, maxElementCount);

src/HotChocolate/Core/src/Types.OffsetPagination/CollectionSegment.cs

@@ -37,6 +37,30 @@ public class CollectionSegment : IPage
             throw new ArgumentNullException(nameof(getTotalCount));
     }
 
+    /// <summary>
+    /// Initializes <see cref="CollectionSegment" />.
+    /// </summary>
+    /// <param name="items">
+    /// The items that belong to this page.
+    /// </param>
+    /// <param name="info">
+    /// Additional information about this page.
+    /// </param>
+    /// <param name="totalCount">
+    /// The total count of the data set / collection that is being paged.
+    /// </param>
+    public CollectionSegment(
+        IReadOnlyCollection<object> items,
+        CollectionSegmentInfo info,
+        int totalCount = 0)
+    {
+        _getTotalCount = _ => new(totalCount);
+        Items = items ??
+            throw new ArgumentNullException(nameof(items));
+        Info = info ??
+            throw new ArgumentNullException(nameof(info));
+    }
+
     /// <summary>
     /// The items that belong to this page.
     /// </summary>
@@ -45,7 +69,12 @@ public class CollectionSegment : IPage
     /// <summary>
     /// Gets more information about this page.
     /// </summary>
-    public IPageInfo Info { get; }
+    public CollectionSegmentInfo Info { get; }
+
+    /// <summary>
+    /// Gets more information about this page.
+    /// </summary>
+    IPageInfo IPage.Info => Info;
 
     /// <summary>
     /// Requests the total count of the data set / collection that is being paged.
@@ -56,7 +85,6 @@ public class CollectionSegment : IPage
     /// <returns>
     /// The total count of the data set / collection.
     /// </returns>
-    public ValueTask<int> GetTotalCountAsync(
-        CancellationToken cancellationToken) =>
+    public ValueTask<int> GetTotalCountAsync(CancellationToken cancellationToken) =>
         _getTotalCount(cancellationToken);
 }

src/HotChocolate/Core/src/Types.OffsetPagination/CollectionSegmentInfo.cs

@@ -9,8 +9,6 @@ public class CollectionSegmentInfo : IPageInfo
     /// <summary>
     /// Initializes <see cref="CollectionSegmentInfo" />.
     /// </summary>
-    /// <param name="hasNextPage"></param>
-    /// <param name="hasPreviousPage"></param>
     public CollectionSegmentInfo(
         bool hasNextPage,
         bool hasPreviousPage)

src/HotChocolate/Core/src/Types.OffsetPagination/CollectionSegment~1.cs

@@ -32,6 +32,27 @@ public class CollectionSegment<T> : CollectionSegment
         Items = items;
     }
 
+    /// <summary>
+    /// Initializes <see cref="CollectionSegment" />.
+    /// </summary>
+    /// <param name="items">
+    /// The items that belong to this page.
+    /// </param>
+    /// <param name="info">
+    /// Additional information about this page.
+    /// </param>
+    /// <param name="totalCount">
+    /// The total count of the data set / collection that is being paged.
+    /// </param>
+    public CollectionSegment(
+        IReadOnlyCollection<T> items,
+        CollectionSegmentInfo info,
+        int totalCount = 0)
+        : base(new CollectionWrapper(items), info, totalCount)
+    {
+        Items = items;
+    }
+
     /// <summary>
     /// The items that belong to this page.
     /// </summary>

src/HotChocolate/Core/src/Types.OffsetPagination/OffsetPaginationAlgorithm.cs

@@ -71,10 +71,7 @@ public abstract class OffsetPaginationAlgorithm<TQuery, TEntity>
 
         items = new SkipLastCollection<TEntity>(items, skipLast: hasNextPage);
 
-        return new CollectionSegment<TEntity>(
-            items,
-            pageInfo,
-            getTotalCount);
+        return new CollectionSegment<TEntity>( items, pageInfo, getTotalCount);
     }
 
     /// <summary>

src/HotChocolate/Core/test/Types.CursorPagination.Tests/ConnectionPageInfoTests.cs

@@ -1,38 +1,29 @@
 using Xunit;
 
-namespace HotChocolate.Types.Pagination
+namespace HotChocolate.Types.Pagination;
+
+public class ConnectionPageInfoTests
 {
-    public class ConnectionPageInfoTests
+    [InlineData(true, true, "a", "b")]
+    [InlineData(true, false, "a", "b")]
+    [InlineData(false, true, "a", "b")]
+    [InlineData(true, true, null, "b")]
+    [InlineData(true, true, "a", null)]
+    [Theory]
+    public void CreatePageInfo_ArgumentsArePassedCorrectly(
+        bool hasNextPage,
+        bool hasPreviousPage,
+        string startCursor,
+        string endCursor)
     {
-        [InlineData(true, true, "a", "b", null)]
-        [InlineData(true, false, "a", "b", null)]
-        [InlineData(false, true, "a", "b", null)]
-        [InlineData(true, true, null, "b", null)]
-        [InlineData(true, true, "a", null, null)]
-        [InlineData(true, true, "a", "b", 1)]
-        [InlineData(true, false, "a", "b", 2)]
-        [InlineData(false, true, "a", "b", 3)]
-        [InlineData(true, true, null, "b", 4)]
-        [InlineData(true, true, "a", null, 5)]
-        [Theory]
-        public void CreatePageInfo_ArgumentsArePassedCorrectly(
-            bool hasNextPage, bool hasPreviousPage,
-            string startCursor, string endCursor,
-            int? totalCount)
-        {
-            // arrange
-            // act
-            var pageInfo = new ConnectionPageInfo(
-                hasNextPage, hasPreviousPage,
-                startCursor, endCursor,
-                totalCount);
+        // arrange
+        // act
+        var pageInfo = new ConnectionPageInfo(hasNextPage, hasPreviousPage, startCursor, endCursor);
 
-            // assert
-            Assert.Equal(hasNextPage, pageInfo.HasNextPage);
-            Assert.Equal(hasPreviousPage, pageInfo.HasPreviousPage);
-            Assert.Equal(startCursor, pageInfo.StartCursor);
-            Assert.Equal(endCursor, pageInfo.EndCursor);
-            Assert.Equal(totalCount, pageInfo.TotalCount);
-        }
+        // assert
+        Assert.Equal(hasNextPage, pageInfo.HasNextPage);
+        Assert.Equal(hasPreviousPage, pageInfo.HasPreviousPage);
+        Assert.Equal(startCursor, pageInfo.StartCursor);
+        Assert.Equal(endCursor, pageInfo.EndCursor);
     }
 }