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diff --git a/src/mongo/db/s/shard_key_index_util.h b/src/mongo/db/s/shard_key_index_util.h
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+/**
+ *    Copyright (C) 2022-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    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
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    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 Server Side 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 "mongo/bson/bsonobj.h"
+#include "mongo/db/catalog/clustered_collection_options_gen.h"
+#include "mongo/db/catalog/index_catalog.h"
+
+namespace mongo {
+
+class Collection;
+class CollectionPtr;
+
+class IndexDescriptor;
+
+class ShardKeyIndex {
+public:
+    /**
+     * Wraps information pertaining to the 'index' used as the shard key.
+     *
+     * A clustered index is not tied to an IndexDescriptor whereas all other types of indexes
+     * are. Either the 'index' is a clustered index and '_clusteredIndexKeyPattern' is
+     * non-empty, or '_indexDescriptor' is non-null and a standard index exists.
+     */
+    ShardKeyIndex(const IndexDescriptor* indexDescriptor);
+    ShardKeyIndex(const ClusteredIndexSpec& clusteredIndexSpec);
+
+    const BSONObj& keyPattern() const;
+    const IndexDescriptor* descriptor() const {
+        return _indexDescriptor;
+    }
+
+private:
+    const IndexDescriptor* _indexDescriptor;
+
+    // Stores the keyPattern when the index is a clustered index and there is no
+    // IndexDescriptor. Empty otherwise.
+    BSONObj _clusteredIndexKeyPattern;
+};
+
+/**
+ * Returns true if the given index is compatible with the shard key pattern.
+ *
+ * If return value is false and errMsg is non-null, the reasons that the existing index is
+ * incompatible will be appended to errMsg.
+ */
+bool isCompatibleWithShardKey(OperationContext* opCtx,
+                              const CollectionPtr& collection,
+                              const IndexCatalogEntry* indexEntry,
+                              const BSONObj& shardKey,
+                              bool requireSingleKey,
+                              std::string* errMsg = nullptr);
+
+/**
+ * Returns an index suitable for shard key range scans if it exists.
+ *
+ * This index:
+ * - must be prefixed by 'shardKey', and
+ * - must not be a partial index.
+ * - must have the simple collation.
+ *
+ * If the parameter 'requireSingleKey' is true, then this index additionally must not be
+ * multi-key.
+ */
+boost::optional<ShardKeyIndex> findShardKeyPrefixedIndex(OperationContext* opCtx,
+                                                         const CollectionPtr& collection,
+                                                         const IndexCatalog* indexCatalog,
+                                                         const BSONObj& shardKey,
+                                                         bool requireSingleKey,
+                                                         std::string* errMsg = nullptr);
+
+/**
+ * Returns true if the given index name is the last remaining index that is compatible with the
+ * shard key index.
+ */
+bool isLastShardKeyIndex(OperationContext* opCtx,
+                         const CollectionPtr& collection,
+                         const IndexCatalog* indexCatalog,
+                         const std::string& indexName,
+                         const BSONObj& shardKey);
+
+}  // namespace mongo