CSHARP-1893: New DistinctMany method which is like Distinct but for array fields.

Author: prchaoz

src/MongoDB.Driver/FilteredMongoCollectionBase.cs

@@ -201,6 +201,15 @@ protected IMongoCollection<TDocument> WrappedCollection
         {
             return _wrappedCollection.Distinct(session, field, CombineFilters(filter), options, cancellationToken);
         }
+        public override IAsyncCursor<TItem> Distinct<TField, TItem>(FieldDefinition<TDocument, TField> field, FilterDefinition<TDocument> filter, DistinctOptions options = null, CancellationToken cancellationToken = default)
+        {
+            return _wrappedCollection.Distinct<TField, TItem>(field, CombineFilters(filter), options, cancellationToken);
+        }
+
+        public override IAsyncCursor<TItem> Distinct<TField, TItem>(IClientSessionHandle session, FieldDefinition<TDocument, TField> field, FilterDefinition<TDocument> filter, DistinctOptions options = null, CancellationToken cancellationToken = default)
+        {
+            return _wrappedCollection.Distinct<TField, TItem>(session, field, CombineFilters(filter), options, cancellationToken);
+        }
 
         public override Task<IAsyncCursor<TField>> DistinctAsync<TField>(FieldDefinition<TDocument, TField> field, FilterDefinition<TDocument> filter, DistinctOptions options = null, CancellationToken cancellationToken = default(CancellationToken))
         {
@@ -212,6 +221,16 @@ protected IMongoCollection<TDocument> WrappedCollection
             return _wrappedCollection.DistinctAsync(session, field, CombineFilters(filter), options, cancellationToken);
         }
 
+        public override Task<IAsyncCursor<TItem>> DistinctAsync<TField, TItem>(FieldDefinition<TDocument, TField> field, FilterDefinition<TDocument> filter, DistinctOptions options = null, CancellationToken cancellationToken = default)
+        {
+            return _wrappedCollection.DistinctAsync<TField, TItem>(field, CombineFilters(filter), options, cancellationToken);
+        }
+
+        public override Task<IAsyncCursor<TItem>> DistinctAsync<TField, TItem>(IClientSessionHandle session, FieldDefinition<TDocument, TField> field, FilterDefinition<TDocument> filter, DistinctOptions options = null, CancellationToken cancellationToken = default)
+        {
+            return _wrappedCollection.DistinctAsync<TField, TItem>(session, field, CombineFilters(filter), options, cancellationToken);
+        }
+
         public override long EstimatedDocumentCount(EstimatedDocumentCountOptions options = null, CancellationToken cancellationToken = default(CancellationToken))
         {
             throw new NotSupportedException("EstimatedDocumentCount is not supported for filtered collections.");

src/MongoDB.Driver/IMongoCollection.cs

@@ -508,6 +508,33 @@ public interface IMongoCollection<TDocument>
         /// </returns>
         IAsyncCursor<TField> Distinct<TField>(IClientSessionHandle session, FieldDefinition<TDocument, TField> field, FilterDefinition<TDocument> filter, DistinctOptions options = null, CancellationToken cancellationToken = default(CancellationToken));
 
+        /// <summary>
+        /// Gets the distinct values for a specified array field.
+        /// </summary>
+        /// <typeparam name="TField">The type of the field.</typeparam>
+        /// <typeparam name="TItem">The type of the result.</typeparam>
+        /// <param name="field">The field.</param>
+        /// <param name="filter">The filter.</param>
+        /// <param name="options">The options.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <returns>A cursor.</returns>
+        IAsyncCursor<TItem> Distinct<TField, TItem>(FieldDefinition<TDocument, TField> field, FilterDefinition<TDocument> filter, DistinctOptions options = null, CancellationToken cancellationToken = default(CancellationToken))
+            where TField : IEnumerable<TItem>;
+
+        /// <summary>
+        /// Gets the distinct values for a specified array field.
+        /// </summary>
+        /// <typeparam name="TField">The type of the field.</typeparam>
+        /// <typeparam name="TItem">The type of the result.</typeparam>
+        /// <param name="session">The session.</param>
+        /// <param name="field">The field.</param>
+        /// <param name="filter">The filter.</param>
+        /// <param name="options">The options.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <returns>A cursor.</returns>
+        IAsyncCursor<TItem> Distinct<TField, TItem>(IClientSessionHandle session, FieldDefinition<TDocument, TField> field, FilterDefinition<TDocument> filter, DistinctOptions options = null, CancellationToken cancellationToken = default(CancellationToken))
+            where TField : IEnumerable<TItem>;
+
         /// <summary>
         /// Gets the distinct values for a specified field.
         /// </summary>
@@ -533,6 +560,33 @@ public interface IMongoCollection<TDocument>
         /// </returns>
         Task<IAsyncCursor<TField>> DistinctAsync<TField>(IClientSessionHandle session, FieldDefinition<TDocument, TField> field, FilterDefinition<TDocument> filter, DistinctOptions options = null, CancellationToken cancellationToken = default(CancellationToken));
 
+        /// <summary>
+        /// Gets the distinct values for a specified array field.
+        /// </summary>
+        /// <typeparam name="TField">The type of the field.</typeparam>
+        /// <typeparam name="TItem">The type of the result.</typeparam>
+        /// <param name="field">The field.</param>
+        /// <param name="filter">The filter.</param>
+        /// <param name="options">The options.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <returns>A cursor.</returns>
+        Task<IAsyncCursor<TItem>> DistinctAsync<TField, TItem>(FieldDefinition<TDocument, TField> field, FilterDefinition<TDocument> filter, DistinctOptions options = null, CancellationToken cancellationToken = default(CancellationToken))
+            where TField : IEnumerable<TItem>;
+
+        /// <summary>
+        /// Gets the distinct values for a specified array field.
+        /// </summary>
+        /// <typeparam name="TField">The type of the field.</typeparam>
+        /// <typeparam name="TItem">The type of the result.</typeparam>
+        /// <param name="session">The session.</param>
+        /// <param name="field">The field.</param>
+        /// <param name="filter">The filter.</param>
+        /// <param name="options">The options.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <returns>A cursor.</returns>
+        Task<IAsyncCursor<TItem>> DistinctAsync<TField, TItem>(IClientSessionHandle session, FieldDefinition<TDocument, TField> field, FilterDefinition<TDocument> filter, DistinctOptions options = null, CancellationToken cancellationToken = default(CancellationToken))
+            where TField : IEnumerable<TItem>;
+
         /// <summary>
         /// Returns an estimate of the number of documents in the collection.
         /// </summary>