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diff --git a/src/mongo/db/pipeline/pipeline_optimizations.h b/src/mongo/db/pipeline/pipeline_optimizations.h
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+/**
+ * Copyright 2013 (c) 10gen Inc.
+ *
+ * This program is free software: you can redistribute it and/or  modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * As a special exception, the copyright holders give permission to link the
+ * code of portions of this program with the OpenSSL library under certain
+ * conditions as described in each individual source file and distribute
+ * linked combinations including the program with the OpenSSL library. You
+ * must comply with the GNU Affero General Public License in all respects for
+ * all of the code used other than as permitted herein. If you modify file(s)
+ * with this exception, you may extend this exception to your version of the
+ * file(s), but you are not obligated to do so. If you do not wish to do so,
+ * delete this exception statement from your version. If you delete this
+ * exception statement from all source files in the program, then also delete
+ * it in the license file.
+ */
+
+/**
+ * This file declares optimizations available on Pipelines. For now they should be considered part
+ * of Pipeline's implementation rather than it's interface.
+ */
+
+#pragma once
+
+#include "mongo/db/pipeline/pipeline.h"
+
+namespace mongo {
+/**
+ * This class holds optimizations applied to a shard Pipeline and a merger Pipeline.
+ *
+ * Each function has the same signature and takes two Pipelines, both as an in/out parameters.
+ */
+class Pipeline::Optimizations::Sharded {
+public:
+    /**
+     * Moves everything before a splittable stage to the shards. If there
+     * are no splittable stages, moves everything to the shards.
+     *
+     * It is not safe to call this optimization multiple times.
+     *
+     * NOTE: looks for SplittableDocumentSources and uses that API
+     */
+    static void findSplitPoint(Pipeline* shardPipe, Pipeline* mergePipe);
+
+    /**
+     * If the final stage on shards is to unwind an array, move that stage to the merger. This
+     * cuts down on network traffic and allows us to take advantage of reduced copying in
+     * unwind.
+     */
+    static void moveFinalUnwindFromShardsToMerger(Pipeline* shardPipe, Pipeline* mergePipe);
+
+    /**
+     * Adds a stage to the end of shardPipe explicitly requesting all fields that mergePipe
+     * needs. This is only done if it heuristically determines that it is needed. This
+     * optimization can reduce the amount of network traffic and can also enable the shards to
+     * convert less source BSON into Documents.
+     */
+    static void limitFieldsSentFromShardsToMerger(Pipeline* shardPipe, Pipeline* mergePipe);
+};
+}  // namespace mongo