SERVER-48050 FCV should be initialized before attempting to restart in-progress index builds

* Refactored repairDatabaseAndCheckVersion by moving FCV logic into
  the FeatureCompatibilityVersion class
* Refactored repairDatabaseAndCheckVersion by separating procedures of
  regular recovery, read-only mode, and repair
* Renamed repairDatabaseAndCheckVersion to repairAndRecoverDatabases
* Moved startup recovery/repair free function into a 'startup_recovery' namespace
* Moved repair free functions into a 'repair' namespace.

renamed:    src/mongo/db/repair_database_and_check_version.cpp -> src/mongo/db/startup_recovery.cpp
renamed:    src/mongo/db/repair_database_and_check_version.h -> src/mongo/db/startup_recovery.h
renamed:    src/mongo/db/repair_database.cpp -> src/mongo/db/repair.cpp
renamed:    src/mongo/db/repair_database.h -> src/mongo/db/repair.h

1 files changed, 63 insertions, 0 deletions

diff --git a/src/mongo/db/repair.h b/src/mongo/db/repair.h
new file mode 100644
index 00000000000..719b11c57a3
--- /dev/null
+++ b/src/mongo/db/repair.h
@@ -0,0 +1,63 @@
+/**
+ *    Copyright (C) 2020-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 <functional>
+#include <string>
+
+#include "mongo/bson/bsonobj.h"
+#include "mongo/db/record_id.h"
+
+namespace mongo {
+class StorageEngine;
+class NamespaceString;
+class OperationContext;
+class Status;
+
+namespace repair {
+
+/**
+ * Repairs a database using a storage engine-specific, best-effort process. Some data may be lost or
+ * modified in the process but the result will be readable collections consistent with their indexes
+ * on a successful return.
+ *
+ * It is expected that the local database will be repaired first when running in repair mode.
+ */
+Status repairDatabase(OperationContext* opCtx, StorageEngine* engine, const std::string& dbName);
+
+/**
+ * Repairs a collection using a storage engine-specific, best-effort process.
+ * Some data may be lost or modified in the process but the result will be a readable collection
+ * consistent with its indexes on a successful return.
+ */
+Status repairCollection(OperationContext* opCtx, StorageEngine* engine, const NamespaceString& nss);
+
+}  // namespace repair
+}  // namespace mongo