CSHARP-5321: Minor refactoring.

mongodb · Jan 22, 2025 · 782ad86 · 782ad86
1 parent cc78201
commit 782ad86
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Showing 5 changed files with 19 additions and 21 deletions.
diff --git a/src/MongoDB.Driver/ClientSideProjectionSnippetsDeserializer.cs b/src/MongoDB.Driver/ClientSideProjectionSnippetsDeserializer.cs
@@ -14,7 +14,6 @@
 */
 
 using System;
-using System.Linq;
 using MongoDB.Bson;
 using MongoDB.Bson.IO;
 using MongoDB.Bson.Serialization;

diff --git a/...ClientSideProjectionExpressionRewriter.cs → ...anslators/ClientSideProjectionRewriter.cs b/...ClientSideProjectionExpressionRewriter.cs → ...anslators/ClientSideProjectionRewriter.cs
@@ -23,29 +23,29 @@
 
 namespace MongoDB.Driver.Linq.Linq3Implementation.Translators.ExpressionToAggregationExpressionTranslators
 {
-    internal static class ClientSideProjectionExpressionRewriter
+    internal static class ClientSideProjectionRewriter
     {
-        public static (AstProjectStage, IBsonSerializer) CreateClientSideProjection(
+        public static (AstProjectStage, IBsonSerializer) CreateProjectSnippetsStage(
             TranslationContext context,
             LambdaExpression projectionLambda,
             IBsonSerializer sourceSerializer)
         {
-            var (snippetsExpression, snippetsProjectionDeserializer) = ClientSideProjectionExpressionRewriter.TranslateLambdaBodyUsingSnippets(context, sourceSerializer, projectionLambda);
-            if (snippetsExpression == null)
+            var (snippetsAst, snippetsProjectionDeserializer) = RewriteProjectionUsingSnippets(context, projectionLambda, sourceSerializer);
+            if (snippetsAst == null)
             {
                 return (null, snippetsProjectionDeserializer);
             }
             else
             {
-                var snippetsTranslation = new AggregationExpression(projectionLambda, snippetsExpression, snippetsProjectionDeserializer);
+                var snippetsTranslation = new AggregationExpression(projectionLambda, snippetsAst, snippetsProjectionDeserializer);
                 return ProjectionHelper.CreateProjectStage(snippetsTranslation);
             }
         }
 
-        private static (AstComputedDocumentExpression, IBsonSerializer) TranslateLambdaBodyUsingSnippets(
+        private static (AstComputedDocumentExpression, IBsonSerializer) RewriteProjectionUsingSnippets(
             TranslationContext context,
-            IBsonSerializer sourceSerializer,
-            LambdaExpression projectionLambda)
+            LambdaExpression projectionLambda,
+            IBsonSerializer sourceSerializer)
         {
             var wireVersion = context.TranslationOptions.CompatibilityLevel.ToWireVersion();
             if (!Feature.FindProjectionExpressions.IsSupported(wireVersion))
@@ -65,9 +65,9 @@ private static (AstComputedDocumentExpression, IBsonSerializer) TranslateLambdaB
             {
                 var snippetsComputedDocument = CreateSnippetsComputedDocument(snippets);
                 var snippetDeserializers = snippets.Select(s => s.Serializer).ToArray();
-                var rewrittenSelectorLamdba = RewriteSelector(projectionLambda, snippets);
-                var rewrittenSelectorDelegate = rewrittenSelectorLamdba.Compile();
-                var clientSideProjectionSnippetsDeserializer = ClientSideProjectionSnippetsDeserializer.Create(projectionLambda.ReturnType, snippetDeserializers, rewrittenSelectorDelegate);
+                var rewrittenProjectionLamdba = RewriteProjection(projectionLambda, snippets);
+                var rewrittenProjectionDelegate = rewrittenProjectionLamdba.Compile();
+                var clientSideProjectionSnippetsDeserializer = ClientSideProjectionSnippetsDeserializer.Create(projectionLambda.ReturnType, snippetDeserializers, rewrittenProjectionDelegate);
                 return (snippetsComputedDocument, clientSideProjectionSnippetsDeserializer);
             }
 
@@ -77,14 +77,13 @@ private static (AstComputedDocumentExpression, IBsonSerializer) TranslateLambdaB
         private static AstComputedDocumentExpression CreateSnippetsComputedDocument(AggregationExpression[] snippets)
         {
             var snippetsArray = AstExpression.ComputedArray(snippets.Select(s => s.Ast));
-            var snippetsdField = AstExpression.ComputedField("_snippets", snippetsArray);
-            return (AstComputedDocumentExpression)AstExpression.ComputedDocument([snippetsdField]);
-
+            var snippetsField = AstExpression.ComputedField("_snippets", snippetsArray);
+            return (AstComputedDocumentExpression)AstExpression.ComputedDocument([snippetsField]);
         }
 
-        private static LambdaExpression RewriteSelector(LambdaExpression selectorLambda, AggregationExpression[] snippets)
+        private static LambdaExpression RewriteProjection(LambdaExpression projectionLambda, AggregationExpression[] snippets)
         {
-            var rewrittenBody = selectorLambda.Body;
+            var rewrittenBody = projectionLambda.Body;
             var snippetsParameter = Expression.Parameter(typeof(object[]), "snippets");
 
             for (var i = 0; i < snippets.Length; i++)

diff --git a/...rs/ExpressionToAggregationExpressionTranslators/ClientSideProjectionSnippetsTranslator.cs b/...rs/ExpressionToAggregationExpressionTranslators/ClientSideProjectionSnippetsTranslator.cs
@@ -79,7 +79,7 @@ public override Expression Visit(Expression node)
                 {
                     var snippet = ExpressionToAggregationExpressionTranslator.Translate(_context, node);
                     _snippets.Add(snippet);
-                    return node;
+                    return node; // suppress any further visiting below this node
                 }
                 catch
                 {

diff --git a/...mentation/Translators/ExpressionToPipelineTranslators/SelectMethodToPipelineTranslator.cs b/...mentation/Translators/ExpressionToPipelineTranslators/SelectMethodToPipelineTranslator.cs
@@ -56,7 +56,7 @@ public static TranslatedPipeline Translate(TranslationContext context, MethodCal
                 }
                 catch (ExpressionNotSupportedException) when (context.TranslationOptions?.EnableClientSideProjections ?? false)
                 {
-                    (projectStage, projectionSerializer) = ClientSideProjectionExpressionRewriter.CreateClientSideProjection(context, selectorLambda, sourceSerializer);
+                    (projectStage, projectionSerializer) = ClientSideProjectionRewriter.CreateProjectSnippetsStage(context, selectorLambda, sourceSerializer);
                 }
 
                 return projectStage == null ?

diff --git a/src/MongoDB.Driver/Linq/LinqProviderAdapter.cs b/src/MongoDB.Driver/Linq/LinqProviderAdapter.cs
@@ -188,8 +188,8 @@ private static RenderedProjectionDefinition<TOutput> TranslateExpressionToProjec
             }
             catch (ExpressionNotSupportedException) when (translationOptions?.EnableClientSideProjections ?? false)
             {
-                var (projectStage, projectionSerializer) = ClientSideProjectionExpressionRewriter.CreateClientSideProjection(context, expression, inputSerializer);
-                var projectionDocument = projectStage == null ? null : AstSimplifier.SimplifyAndConvert(projectStage).Render()["$project"].AsBsonDocument;
+                var (projectStage, projectionSerializer) = ClientSideProjectionRewriter.CreateProjectSnippetsStage(context, expression, inputSerializer);
+                var projectionDocument = projectStage == null ? null : simplifier.VisitAndConvert(projectStage).Render()["$project"].AsBsonDocument;
                 return new RenderedProjectionDefinition<TOutput>(projectionDocument, (IBsonSerializer<TOutput>)projectionSerializer);
             }
         }