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diff --git a/src/mongo/db/update/push_node.h b/src/mongo/db/update/push_node.h
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+++ b/src/mongo/db/update/push_node.h
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+/**
+ * Copyright (C) 2017 MongoDB 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.
+ */
+
+#pragma once
+
+#include <boost/optional.hpp>
+#include <limits>
+#include <vector>
+
+#include "mongo/db/update/path_creating_node.h"
+#include "mongo/db/update/push_sorter.h"
+#include "mongo/stdx/memory.h"
+
+namespace mongo {
+
+class PushNode final : public PathCreatingNode {
+public:
+    PushNode()
+        : _slice(std::numeric_limits<long long>::max()),
+          _position(std::numeric_limits<long long>::max()) {}
+    Status init(BSONElement modExpr, const CollatorInterface* collator) final;
+
+    std::unique_ptr<UpdateNode> clone() const final {
+        return stdx::make_unique<PushNode>(*this);
+    }
+
+    void setCollator(const CollatorInterface* collator) final {
+        if (_sort) {
+            invariant(!_sort->collator);
+            _sort->collator = collator;
+        }
+    }
+
+protected:
+    UpdateExistingElementResult updateExistingElement(mutablebson::Element* element,
+                                                      std::shared_ptr<FieldRef> elementPath,
+                                                      LogBuilder* logBuilder) const final;
+    void setValueForNewElement(mutablebson::Element* element) const final;
+
+private:
+    /**
+     * Used to describe the result of the PerformPush operation. Note that appending to any empty
+     * array is always considered kModifyArray. That's because we want $push onto an empty to array
+     * to trigger a log entry with a $set on the entire array.
+     */
+    enum class PushResult {
+        kNoOp,                // The array is left exactly as it was.
+        kAppendToEndOfArray,  // The only change to the array is items appended to the end.
+        kModifyArray          // Any other modification of the array.
+    };
+
+    static PushResult insertElementsWithPosition(mutablebson::Element* array,
+                                                 long long position,
+                                                 const std::vector<BSONElement> valuesToPush);
+    PushResult performPush(mutablebson::Element* element, FieldRef* elementPath) const;
+
+    static const StringData kEachClauseName;
+    static const StringData kSliceClauseName;
+    static const StringData kSortClauseName;
+    static const StringData kPositionClauseName;
+
+    std::vector<BSONElement> _valuesToPush;
+    long long _slice;
+    long long _position;
+    boost::optional<PatternElementCmp> _sort;
+};
+
+}  // namespace mongo