/// compact.cpp

/**
*    Copyright (C) 2013 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,b
*    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.
*/

#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kCommand

#include <string>
#include <vector>

#include "mongo/db/auth/action_set.h"
#include "mongo/db/auth/action_type.h"
#include "mongo/db/auth/privilege.h"
#include "mongo/db/background.h"
#include "mongo/db/catalog/collection.h"
#include "mongo/db/catalog/database.h"
#include "mongo/db/commands.h"
#include "mongo/db/concurrency/d_concurrency.h"
#include "mongo/db/curop.h"
#include "mongo/db/db_raii.h"
#include "mongo/db/index_builder.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/operation_context_impl.h"
#include "mongo/db/repl/replication_coordinator_global.h"
#include "mongo/util/log.h"

namespace mongo {

using std::string;
using std::stringstream;

class CompactCmd : public Command {
public:
    virtual bool isWriteCommandForConfigServer() const {
        return false;
    }
    virtual bool adminOnly() const {
        return false;
    }
    virtual bool slaveOk() const {
        return true;
    }
    virtual bool maintenanceMode() const {
        return true;
    }
    virtual void addRequiredPrivileges(const std::string& dbname,
                                       const BSONObj& cmdObj,
                                       std::vector<Privilege>* out) {
        ActionSet actions;
        actions.addAction(ActionType::compact);
        out->push_back(Privilege(parseResourcePattern(dbname, cmdObj), actions));
    }
    virtual void help(stringstream& help) const {
        help << "compact collection\n"
                "warning: this operation locks the database and is slow. you can cancel with "
                "killOp()\n"
                "{ compact : <collection_name>, [force:<bool>], [validate:<bool>],\n"
                "  [paddingFactor:<num>], [paddingBytes:<num>] }\n"
                "  force - allows to run on a replica set primary\n"
                "  validate - check records are noncorrupt before adding to newly compacting "
                "extents. slower but safer (defaults to true in this version)\n";
    }
    CompactCmd() : Command("compact") {}

    virtual bool run(OperationContext* txn,
                     const string& db,
                     BSONObj& cmdObj,
                     int,
                     string& errmsg,
                     BSONObjBuilder& result) {
        const std::string nsToCompact = parseNsCollectionRequired(db, cmdObj);

        repl::ReplicationCoordinator* replCoord = repl::getGlobalReplicationCoordinator();
        if (replCoord->getMemberState().primary() && !cmdObj["force"].trueValue()) {
            errmsg =
                "will not run compact on an active replica set primary as this is a slow blocking "
                "operation. use force:true to force";
            return false;
        }

        NamespaceString ns(nsToCompact);
        if (!ns.isNormal()) {
            errmsg = "bad namespace name";
            return false;
        }

        if (ns.isSystem()) {
            // items in system.* cannot be moved as there might be pointers to them
            // i.e. system.indexes entries are pointed to from NamespaceDetails
            errmsg = "can't compact a system namespace";
            return false;
        }

        CompactOptions compactOptions;

        if (cmdObj["preservePadding"].trueValue()) {
            compactOptions.paddingMode = CompactOptions::PRESERVE;
            if (cmdObj.hasElement("paddingFactor") || cmdObj.hasElement("paddingBytes")) {
                errmsg = "cannot mix preservePadding and paddingFactor|paddingBytes";
                return false;
            }
        } else if (cmdObj.hasElement("paddingFactor") || cmdObj.hasElement("paddingBytes")) {
            compactOptions.paddingMode = CompactOptions::MANUAL;
            if (cmdObj.hasElement("paddingFactor")) {
                compactOptions.paddingFactor = cmdObj["paddingFactor"].Number();
                if (compactOptions.paddingFactor < 1 || compactOptions.paddingFactor > 4) {
                    errmsg = "invalid padding factor";
                    return false;
                }
            }
            if (cmdObj.hasElement("paddingBytes")) {
                compactOptions.paddingBytes = cmdObj["paddingBytes"].numberInt();
                if (compactOptions.paddingBytes < 0 ||
                    compactOptions.paddingBytes > (1024 * 1024)) {
                    errmsg = "invalid padding bytes";
                    return false;
                }
            }
        }

        if (cmdObj.hasElement("validate"))
            compactOptions.validateDocuments = cmdObj["validate"].trueValue();


        ScopedTransaction transaction(txn, MODE_IX);
        AutoGetDb autoDb(txn, db, MODE_X);
        Database* const collDB = autoDb.getDb();
        Collection* collection = collDB ? collDB->getCollection(ns) : NULL;

        // If db/collection does not exist, short circuit and return.
        if (!collDB || !collection) {
            errmsg = "namespace does not exist";
            return false;
        }

        OldClientContext ctx(txn, ns);
        BackgroundOperation::assertNoBgOpInProgForNs(ns.ns());

        if (collection->isCapped()) {
            errmsg = "cannot compact a capped collection";
            return false;
        }

        log() << "compact " << ns << " begin, options: " << compactOptions.toString();

        StatusWith<CompactStats> status = collection->compact(txn, &compactOptions);
        if (!status.isOK())
            return appendCommandStatus(result, status.getStatus());

        if (status.getValue().corruptDocuments > 0)
            result.append("invalidObjects", status.getValue().corruptDocuments);

        log() << "compact " << ns << " end";

        return true;
    }
};
static CompactCmd compactCmd;
}