private PipelineDefinition <TDocument, TResult> CreateFilteredPipeline <TResult>(PipelineDefinition <TDocument, TResult> pipeline)
{
const string matchOperatorName = "$match";
var filterStage = new DelegatedPipelineStageDefinition <TDocument, TDocument>(
matchOperatorName,
(s, sr) =>
{
var renderedFilter = _filter.Render(s, sr);
return(new RenderedPipelineStageDefinition <TDocument>(matchOperatorName, new BsonDocument(matchOperatorName, renderedFilter), s));
});
var filterPipeline = new PipelineStagePipelineDefinition <TDocument, TDocument>(new[] { filterStage });
var combinedPipeline = new CombinedPipelineDefinition <TDocument, TDocument, TResult>(
filterPipeline,
pipeline);
return(new OptimizingPipelineDefinition <TDocument, TResult>(combinedPipeline));
}
// public methods
public override Task <IAsyncCursor <TResult> > AggregateAsync <TResult>(PipelineDefinition <TDocument, TResult> pipeline, AggregateOptions options = null, CancellationToken cancellationToken = default(CancellationToken))
{
const string matchOperatorName = "$match";
var filterStage = new DelegatedPipelineStageDefinition <TDocument, TDocument>(
matchOperatorName,
(s, sr) =>
{
var renderedFilter = _filter.Render(s, sr);
return(new RenderedPipelineStageDefinition <TDocument>(matchOperatorName, new BsonDocument(matchOperatorName, renderedFilter), s));
});
var filterPipeline = new PipelineStagePipelineDefinition <TDocument, TDocument>(new[] { filterStage });
var combinedPipeline = new CombinedPipelineDefinition <TDocument, TDocument, TResult>(
filterPipeline,
pipeline);
var optimizedPipeline = new OptimizingPipelineDefinition <TDocument, TResult>(combinedPipeline);
return(_wrappedCollection.AggregateAsync(optimizedPipeline, options, cancellationToken));
}
