// repair_cursor.cpp


/**
 *    Copyright (C) 2018-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.
 */

#include "mongo/platform/basic.h"

#include <memory>

#include "mongo/db/auth/authorization_session.h"
#include "mongo/db/catalog/collection.h"
#include "mongo/db/client.h"
#include "mongo/db/commands.h"
#include "mongo/db/cursor_manager.h"
#include "mongo/db/db_raii.h"
#include "mongo/db/exec/multi_iterator.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/query/cursor_response.h"

namespace mongo {

using std::string;

class RepairCursorCmd : public BasicCommand {
public:
    RepairCursorCmd() : BasicCommand("repairCursor") {}

    virtual bool supportsWriteConcern(const BSONObj& cmd) const override {
        return false;
    }
    AllowedOnSecondary secondaryAllowed(ServiceContext*) const override {
        return AllowedOnSecondary::kAlways;
    }

    virtual Status checkAuthForCommand(Client* client,
                                       const std::string& dbname,
                                       const BSONObj& cmdObj) const {
        ActionSet actions;
        actions.addAction(ActionType::find);
        Privilege p(parseResourcePattern(dbname, cmdObj), actions);
        if (AuthorizationSession::get(client)->isAuthorizedForPrivilege(p))
            return Status::OK();
        return Status(ErrorCodes::Unauthorized, "Unauthorized");
    }

    virtual bool run(OperationContext* opCtx,
                     const string& dbname,
                     const BSONObj& cmdObj,
                     BSONObjBuilder& result) {
        NamespaceString ns(parseNs(dbname, cmdObj));

        AutoGetCollectionForReadCommand ctx(opCtx, ns);

        Collection* collection = ctx.getCollection();
        if (!collection) {
            uasserted(ErrorCodes::NamespaceNotFound, "ns does not exist: " + ns.ns());
        }

        auto cursor = collection->getRecordStore()->getCursorForRepair(opCtx);
        if (!cursor) {
            uasserted(ErrorCodes::CommandNotSupported, "repair iterator not supported");
        }

        std::unique_ptr<WorkingSet> ws(new WorkingSet());
        std::unique_ptr<MultiIteratorStage> stage(
            new MultiIteratorStage(opCtx, ws.get(), collection));
        stage->addIterator(std::move(cursor));

        auto statusWithPlanExecutor = PlanExecutor::make(
            opCtx, std::move(ws), std::move(stage), collection, PlanExecutor::YIELD_AUTO);
        invariant(statusWithPlanExecutor.isOK());
        auto exec = std::move(statusWithPlanExecutor.getValue());

        exec->saveState();
        exec->detachFromOperationContext();

        auto pinnedCursor = CursorManager::get(opCtx)->registerCursor(
            opCtx,
            {std::move(exec),
             ns,
             AuthorizationSession::get(opCtx->getClient())->getAuthenticatedUserNames(),
             repl::ReadConcernArgs::get(opCtx),
             cmdObj,
             ClientCursorParams::LockPolicy::kLockExternally,
             {Privilege(parseResourcePattern(dbname, cmdObj), ActionType::find)}});

        appendCursorResponseObject(
            pinnedCursor.getCursor()->cursorid(), ns.ns(), BSONArray(), &result);

        return true;
    }
} repairCursorCmd;
}