CSHARP-4186: Refactor AstSetWindowFieldsWindowExpression.

Author: rstam

src/MongoDB.Driver/Linq/Linq3Implementation/Ast/AstNodeType.cs

@@ -24,6 +24,7 @@ internal enum AstNodeType
         AndExpression,
         AndFilter,
         BinaryExpression,
+        BinaryWindowExpression,
         BitsAllClearFilterOperation,
         BitsAllSetFilterOperation,
         BitsAnyClearFilterOperation,
@@ -52,8 +53,10 @@ internal enum AstNodeType
         DateToStringExpression,
         DateTruncExpression,
         DensifyStage,
+        DerivativeOrIntegralWindowExpression,
         ElemMatchFilterOperation,
         ExistsFilterOperation,
+        ExponentialMovingAverageWindowExpression,
         ExprFilter,
         FacetStage,
         FacetStageFacet,
@@ -98,6 +101,7 @@ internal enum AstNodeType
         NinFilterOperation,
         NorFilter,
         NotFilterOperation,
+        NullaryWindowExpression,
         OrExpression,
         OrFilter,
         OutStage,
@@ -120,7 +124,8 @@ internal enum AstNodeType
         RTrimExpression,
         SampleStage,
         SetStage,
-        SetWindowFieldsWindowExpression,
+        SetWindowFieldsStage,
+        ShiftWindowExpression,
         SizeFilterOperation,
         SkipStage,
         SliceExpression,
@@ -133,12 +138,14 @@ internal enum AstNodeType
         TrimExpression,
         TypeFilterOperation,
         UnaryExpression,
+        UnaryWindowExpression,
         UnionWithStage,
         UnsetStage,
         UnwindStage,
         VarBinding,
         VarExpression,
         WhereFilter,
+        WindowField,
         ZipExpression
     }
 }

src/MongoDB.Driver/Linq/Linq3Implementation/Ast/AstSortField.cs

@@ -0,0 +1,80 @@
+/* Copyright 2010-present MongoDB Inc.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+using MongoDB.Bson;
+using MongoDB.Driver.Core.Misc;
+
+namespace MongoDB.Driver.Linq.Linq3Implementation.Ast
+{
+    internal static class AstSort
+    {
+        public static AstSortField Field(string path, AstSortOrder order)
+        {
+            return new AstSortField(path, order);
+        }
+    }
+
+    internal sealed class AstSortField
+    {
+        private readonly string _path;
+        private readonly AstSortOrder _order;
+
+        public AstSortField(string path, AstSortOrder order)
+        {
+            _path = Ensure.IsNotNull(path, nameof(path));
+            _order = Ensure.IsNotNull(order, nameof(order));
+        }
+
+        public AstSortOrder Order => _order;
+        public string Path => _path;
+
+        public BsonElement RenderAsElement()
+        {
+            return new BsonElement(_path, _order.Render());
+        }
+
+        public override string ToString() => RenderAsElement().ToJson();
+    }
+
+    internal abstract class AstSortOrder
+    {
+        private readonly static AstSortOrder __ascending = new AstAscendingSortOrder();
+        private readonly static AstSortOrder __descending = new AstDescendingSortOrder();
+        private readonly static AstSortOrder __metaTextScore = new AstMetaTextScoreSortOrder();
+
+        public static AstSortOrder Ascending => __ascending;
+        public static AstSortOrder Descending => __descending;
+        public static AstSortOrder MetaTextScore => __metaTextScore;
+
+        public abstract BsonValue Render();
+
+        public override string ToString() => Render().ToJson();
+    }
+
+    internal sealed class AstAscendingSortOrder : AstSortOrder
+    {
+        public override BsonValue Render() => 1;
+    }
+
+    internal sealed class AstDescendingSortOrder : AstSortOrder
+    {
+        public override BsonValue Render() => -1;
+    }
+
+    internal sealed class AstMetaTextScoreSortOrder : AstSortOrder
+    {
+        public override BsonValue Render() => new BsonDocument("$meta", "textScore");
+    }
+}

src/MongoDB.Driver/Linq/Linq3Implementation/Ast/AstSortFields.cs

@@ -0,0 +1,52 @@
+/* Copyright 2010-present MongoDB Inc.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using MongoDB.Bson;
+using MongoDB.Driver.Core.Misc;
+using MongoDB.Driver.Linq.Linq3Implementation.Misc;
+
+namespace MongoDB.Driver.Linq.Linq3Implementation.Ast
+{
+    internal sealed class AstSortFields : IEnumerable<AstSortField>
+    {
+        private readonly IReadOnlyList<AstSortField> _fields;
+
+        public AstSortFields(IEnumerable<AstSortField> fields)
+        {
+            _fields = Ensure.IsNotNull(fields, nameof(fields)).AsReadOnlyList();
+        }
+
+        public IReadOnlyList<AstSortField> Fields => _fields;
+
+        public IEnumerator<AstSortField> GetEnumerator() => _fields.GetEnumerator();
+        IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
+
+        public AstSortFields AddSortField(AstSortField field)
+        {
+            Ensure.IsNotNull(field, nameof(field));
+            return new AstSortFields(_fields.Concat(new[] { field }));
+        }
+
+        public BsonDocument Render()
+        {
+            return new BsonDocument(_fields.Select(f => f.RenderAsElement()));
+        }
+
+        public override string ToString() => Render().ToJson();
+    }
+}

src/MongoDB.Driver/Linq/Linq3Implementation/Ast/AstWindowField.cs

@@ -0,0 +1,68 @@
+/* Copyright 2010-present MongoDB Inc.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+using MongoDB.Bson;
+using MongoDB.Driver.Core.Misc;
+using MongoDB.Driver.Linq.Linq3Implementation.Ast.Expressions;
+using MongoDB.Driver.Linq.Linq3Implementation.Ast.Visitors;
+
+namespace MongoDB.Driver.Linq.Linq3Implementation.Ast
+{
+    internal sealed class AstWindowField : AstNode
+    {
+        private readonly string _path;
+        private readonly AstWindowExpression _value;
+
+        public AstWindowField(string path, AstWindowExpression value)
+        {
+            _path = Ensure.IsNotNull(path, nameof(path));
+            _value = Ensure.IsNotNull(value, nameof(value));
+        }
+
+        public override AstNodeType NodeType => AstNodeType.WindowField;
+        public string Path => _path;
+        public AstWindowExpression Value => _value;
+
+        public override AstNode Accept(AstNodeVisitor visitor)
+        {
+            return visitor.VisitWindowField(this);
+        }
+
+        public override BsonValue Render()
+        {
+            return new BsonDocument(RenderAsElement());
+        }
+
+        public BsonElement RenderAsElement()
+        {
+            return new BsonElement(_path, _value.Render());
+        }
+
+        public override string ToString()
+        {
+            return $"\"{_path}\" : {_value.Render().ToJson()}";
+        }
+
+        public AstWindowField Update(string path, AstWindowExpression value)
+        {
+            if (path == _path && value == _value)
+            {
+                return this;
+            }
+
+            return new AstWindowField(path, value);
+        }
+    }
+}

src/MongoDB.Driver/Linq/Linq3Implementation/Ast/Expressions/AstBinaryWindowExpression.cs

@@ -0,0 +1,67 @@
+/* Copyright 2010-present MongoDB Inc.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+using MongoDB.Bson;
+using MongoDB.Driver.Core.Misc;
+using MongoDB.Driver.Linq.Linq3Implementation.Ast.Visitors;
+
+namespace MongoDB.Driver.Linq.Linq3Implementation.Ast.Expressions
+{
+    internal sealed class AstBinaryWindowExpression : AstWindowExpression
+    {
+        private readonly AstExpression _arg1;
+        private readonly AstExpression _arg2;
+        private readonly AstBinaryWindowOperator _operator;
+        private readonly AstWindow _window;
+
+        public AstBinaryWindowExpression(AstBinaryWindowOperator @operator, AstExpression arg1, AstExpression arg2, AstWindow window)
+        {
+            _operator = @operator;
+            _arg1 = Ensure.IsNotNull(arg1, nameof(arg1));
+            _arg2 = Ensure.IsNotNull(arg2, nameof(arg2));
+            _window = window;
+        }
+
+        public AstExpression Arg1 => _arg1;
+        public AstExpression Arg2 => _arg2;
+        public override AstNodeType NodeType => AstNodeType.BinaryWindowExpression;
+        public AstBinaryWindowOperator Operator => _operator;
+        public AstWindow Window => _window;
+
+        public override AstNode Accept(AstNodeVisitor visitor)
+        {
+            return visitor.VisitBinaryWindowExpression(this);
+        }
+
+        public override BsonValue Render()
+        {
+            return new BsonDocument
+            {
+                { _operator.Render(), new BsonArray { _arg1.Render(), _arg2.Render() } },
+                { "window", _window?.Render(), _window != null }
+            };
+        }
+
+        public AstBinaryWindowExpression Update(AstBinaryWindowOperator @operator, AstExpression arg1, AstExpression arg2, AstWindow window)
+        {
+            if (@operator == _operator && arg1 == _arg1 && arg2 == _arg2 && window == _window)
+            {
+                return this;
+            }
+
+            return new AstBinaryWindowExpression(@operator, arg1, arg2, window);
+        }
+    }
+}

src/MongoDB.Driver/Linq/Linq3Implementation/Ast/Expressions/AstBinaryWindowOperator.cs

@@ -0,0 +1,38 @@
+/* Copyright 2010-present MongoDB Inc.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+using System;
+
+namespace MongoDB.Driver.Linq.Linq3Implementation.Ast.Expressions
+{
+    internal enum AstBinaryWindowOperator
+    {
+        CovariancePopulation,
+        CovarianceSample
+    }
+
+    internal static class AstBinaryWindowOperatorExtensions
+    {
+        public static string Render(this AstBinaryWindowOperator @operator)
+        {
+            return @operator switch
+            {
+                AstBinaryWindowOperator.CovariancePopulation => "$covariancePop",
+                AstBinaryWindowOperator.CovarianceSample => "$covarianceSamp",
+                _ => throw new InvalidOperationException($"Unexpected binary window operator: {@operator}.")
+            };
+        }
+    }
+}