public override RenderedPipelineStageDefinition <IGrouping <TKey, TInput> > Render(
IBsonSerializer <TInput> inputSerializer,
IBsonSerializerRegistry serializerRegistry,
LinqProvider linqProvider)
{
if (linqProvider != LinqProvider.V3)
{
throw new InvalidOperationException("GroupExpressionStageDefinitions can only be used with LINQ3.");
}
var expression = CreateExpression(inputSerializer);
expression = PartialEvaluator.EvaluatePartially(expression);
var context = TranslationContext.Create(expression, inputSerializer);
var unoptimizedPipeline = ExpressionToPipelineTranslator.Translate(context, expression);
var pipeline = AstPipelineOptimizer.Optimize(unoptimizedPipeline);
var groupStageDocument = pipeline.Stages[0].Render().AsBsonDocument;
var renderedGroupStage = new RenderedPipelineStageDefinition <IGrouping <TKey, TInput> >("$group", groupStageDocument, new DummyIGroupingSerializer());
var projectStageDocument = pipeline.Stages[1].Render().AsBsonDocument;
_renderedProjectStage = new RenderedPipelineStageDefinition <TOutput>("$project", projectStageDocument, (IBsonSerializer <TOutput>)pipeline.OutputSerializer);
return(renderedGroupStage);
}
private ProjectedResult <TResult> Group <TKey, TResult>(Expression <Func <Root, TKey> > idProjector, Expression <Func <IGrouping <TKey, Root>, TResult> > groupProjector, ExpressionTranslationOptions translationOptions)
{
var queryable = __collection.AsQueryable()
.GroupBy(idProjector)
.Select(groupProjector);
var collectionSerializer = (IBsonDocumentSerializer)BsonSerializer.LookupSerializer <Root>();
var context = TranslationContext.Create(queryable.Expression, collectionSerializer);
var pipeline = ExpressionToPipelineTranslator.Translate(context, queryable.Expression);
pipeline = AstPipelineOptimizer.Optimize(pipeline);
var stages = pipeline.Stages.Select(s => s.Render()).Cast <BsonDocument>().ToList();
stages.Insert(1, new BsonDocument("$sort", new BsonDocument("_id", 1))); // force a standard order for testing purposes
var pipelineDefinition = new BsonDocumentStagePipelineDefinition <Root, TResult>(stages, outputSerializer: (IBsonSerializer <TResult>)pipeline.OutputSerializer);
var results = __collection.Aggregate(pipelineDefinition).ToList();
stages.RemoveAt(1); // remove $sort added above for predictable testing
return(new ProjectedResult <TResult>
{
Stages = stages,
Value = results[0]
});
}
public static ExecutableQuery <TDocument, TOutput, TResult> Create <TDocument, TOutput, TResult>(
IMongoCollection <TDocument> collection,
AggregateOptions options,
AstPipeline unoptimizedPipeline,
IExecutableQueryFinalizer <TOutput, TResult> finalizer)
{
var pipeline = AstPipelineOptimizer.Optimize(unoptimizedPipeline);
return(new ExecutableQuery <TDocument, TOutput, TResult>(collection, options, unoptimizedPipeline, pipeline, finalizer));
}