SERVER-24508 DocumentComparator and ValueComparator

 - Changes the Document/Value library to require comparisons
   to be made in the context of a comparator object. This is
   prep work for full collation support in the aggregation
   system.
 - Adds injectExpressionContext() to propagate the
   ExpressionContext containing the comparator object to all
   DocumentSource, Accumulator, and Expression instances
   involved in the Pipeline.

1 files changed, 6 insertions, 9 deletions

diff --git a/src/mongo/db/pipeline/pipeline.h b/src/mongo/db/pipeline/pipeline.h
index d577b5fc151..531411fae60 100644
--- a/src/mongo/db/pipeline/pipeline.h
+++ b/src/mongo/db/pipeline/pipeline.h
@@ -107,15 +107,6 @@ public:
     void reattachToOperationContext(OperationContext* opCtx);
 
     /**
-     * Sets the collator on this Pipeline. parseCommand() will return a Pipeline with its collator
-     * already set from the parsed request (if applicable), but this setter method can be used to
-     * later override the Pipeline's original collator.
-     *
-     * The Pipeline's collator can be retrieved with getContext()->collator.
-     */
-    void setCollator(std::unique_ptr<CollatorInterface> collator);
-
-    /**
       Split the current Pipeline into a Pipeline for each shard, and
       a Pipeline that combines the results within mongos.
 
@@ -142,6 +133,12 @@ public:
     void optimizePipeline();
 
     /**
+     * Propagates a reference to the ExpressionContext to all of the pipeline's contained stages and
+     * expressions.
+     */
+    void injectExpressionContext(const boost::intrusive_ptr<ExpressionContext>& expCtx);
+
+    /**
      * Returns any other collections involved in the pipeline in addition to the collection the
      * aggregation is run on.
      */