Merge "Fix positioning of jQuery.tipsy tooltip arrows"

[mediawiki.git] / maintenance / Maintenance.php

<?php
/**
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 * @ingroup Maintenance
 * @defgroup Maintenance Maintenance
 */

// Bail on old versions of PHP, or if composer has not been run yet to install
// dependencies. Using dirname( __FILE__ ) here because __DIR__ is PHP5.3+.
// @codingStandardsIgnoreStart MediaWiki.Usage.DirUsage.FunctionFound
require_once dirname( __FILE__ ) . '/../includes/PHPVersionCheck.php';
// @codingStandardsIgnoreEnd
wfEntryPointCheck( 'cli' );

/**
 * @defgroup MaintenanceArchive Maintenance archives
 * @ingroup Maintenance
 */

// Define this so scripts can easily find doMaintenance.php
define( 'RUN_MAINTENANCE_IF_MAIN', __DIR__ . '/doMaintenance.php' );
define( 'DO_MAINTENANCE', RUN_MAINTENANCE_IF_MAIN ); // original name, harmless

$maintClass = false;

use MediaWiki\Logger\LoggerFactory;

/**
 * Abstract maintenance class for quickly writing and churning out
 * maintenance scripts with minimal effort. All that _must_ be defined
 * is the execute() method. See docs/maintenance.txt for more info
 * and a quick demo of how to use it.
 *
 * @author Chad Horohoe <chad@anyonecanedit.org>
 * @since 1.16
 * @ingroup Maintenance
 */
abstract class Maintenance {
        /**
         * Constants for DB access type
         * @see Maintenance::getDbType()
         */
        const DB_NONE = 0;
        const DB_STD = 1;
        const DB_ADMIN = 2;

        // Const for getStdin()
        const STDIN_ALL = 'all';

        // This is the desired params
        protected $mParams = array();

        // Array of mapping short parameters to long ones
        protected $mShortParamsMap = array();

        // Array of desired args
        protected $mArgList = array();

        // This is the list of options that were actually passed
        protected $mOptions = array();

        // This is the list of arguments that were actually passed
        protected $mArgs = array();

        // Name of the script currently running
        protected $mSelf;

        // Special vars for params that are always used
        protected $mQuiet = false;
        protected $mDbUser, $mDbPass;

        // A description of the script, children should change this
        protected $mDescription = '';

        // Have we already loaded our user input?
        protected $mInputLoaded = false;

        /**
         * Batch size. If a script supports this, they should set
         * a default with setBatchSize()
         *
         * @var int
         */
        protected $mBatchSize = null;

        // Generic options added by addDefaultParams()
        private $mGenericParameters = array();
        // Generic options which might or not be supported by the script
        private $mDependantParameters = array();

        /**
         * Used by getDB() / setDB()
         * @var IDatabase
         */
        private $mDb = null;

        /**
         * Used when creating separate schema files.
         * @var resource
         */
        public $fileHandle;

        /**
         * Accessible via getConfig()
         *
         * @var Config
         */
        private $config;

        /**
         * Used to read the options in the order they were passed.
         * Useful for option chaining (Ex. dumpBackup.php). It will
         * be an empty array if the options are passed in through
         * loadParamsAndArgs( $self, $opts, $args ).
         *
         * This is an array of arrays where
         * 0 => the option and 1 => parameter value.
         *
         * @var array
         */
        public $orderedOptions = array();

        /**
         * Default constructor. Children should call this *first* if implementing
         * their own constructors
         */
        public function __construct() {
                // Setup $IP, using MW_INSTALL_PATH if it exists
                global $IP;
                $IP = strval( getenv( 'MW_INSTALL_PATH' ) ) !== ''
                        ? getenv( 'MW_INSTALL_PATH' )
                        : realpath( __DIR__ . '/..' );

                $this->addDefaultParams();
                register_shutdown_function( array( $this, 'outputChanneled' ), false );
        }

        /**
         * Should we execute the maintenance script, or just allow it to be included
         * as a standalone class? It checks that the call stack only includes this
         * function and "requires" (meaning was called from the file scope)
         *
         * @return bool
         */
        public static function shouldExecute() {
                global $wgCommandLineMode;

                if ( !function_exists( 'debug_backtrace' ) ) {
                        // If someone has a better idea...
                        return $wgCommandLineMode;
                }

                $bt = debug_backtrace();
                $count = count( $bt );
                if ( $count < 2 ) {
                        return false; // sanity
                }
                if ( $bt[0]['class'] !== 'Maintenance' || $bt[0]['function'] !== 'shouldExecute' ) {
                        return false; // last call should be to this function
                }
                $includeFuncs = array( 'require_once', 'require', 'include', 'include_once' );
                for ( $i = 1; $i < $count; $i++ ) {
                        if ( !in_array( $bt[$i]['function'], $includeFuncs ) ) {
                                return false; // previous calls should all be "requires"
                        }
                }

                return true;
        }

        /**
         * Do the actual work. All child classes will need to implement this
         */
        abstract public function execute();

        /**
         * Add a parameter to the script. Will be displayed on --help
         * with the associated description
         *
         * @param string $name The name of the param (help, version, etc)
         * @param string $description The description of the param to show on --help
         * @param bool $required Is the param required?
         * @param bool $withArg Is an argument required with this option?
         * @param string $shortName Character to use as short name
         * @param bool $multiOccurrence Can this option be passed multiple times?
         */
        protected function addOption( $name, $description, $required = false,
                $withArg = false, $shortName = false, $multiOccurrence = false
        ) {
                $this->mParams[$name] = array(
                        'desc' => $description,
                        'require' => $required,
                        'withArg' => $withArg,
                        'shortName' => $shortName,
                        'multiOccurrence' => $multiOccurrence
                );

                if ( $shortName !== false ) {
                        $this->mShortParamsMap[$shortName] = $name;
                }
        }

        /**
         * Checks to see if a particular param exists.
         * @param string $name The name of the param
         * @return bool
         */
        protected function hasOption( $name ) {
                return isset( $this->mOptions[$name] );
        }

        /**
         * Get an option, or return the default.
         *
         * If the option was added to support multiple occurrences,
         * this will return an array.
         *
         * @param string $name The name of the param
         * @param mixed $default Anything you want, default null
         * @return mixed
         */
        protected function getOption( $name, $default = null ) {
                if ( $this->hasOption( $name ) ) {
                        return $this->mOptions[$name];
                } else {
                        // Set it so we don't have to provide the default again
                        $this->mOptions[$name] = $default;

                        return $this->mOptions[$name];
                }
        }

        /**
         * Add some args that are needed
         * @param string $arg Name of the arg, like 'start'
         * @param string $description Short description of the arg
         * @param bool $required Is this required?
         */
        protected function addArg( $arg, $description, $required = true ) {
                $this->mArgList[] = array(
                        'name' => $arg,
                        'desc' => $description,
                        'require' => $required
                );
        }

        /**
         * Remove an option.  Useful for removing options that won't be used in your script.
         * @param string $name The option to remove.
         */
        protected function deleteOption( $name ) {
                unset( $this->mParams[$name] );
        }

        /**
         * Set the description text.
         * @param string $text The text of the description
         */
        protected function addDescription( $text ) {
                $this->mDescription = $text;
        }

        /**
         * Does a given argument exist?
         * @param int $argId The integer value (from zero) for the arg
         * @return bool
         */
        protected function hasArg( $argId = 0 ) {
                return isset( $this->mArgs[$argId] );
        }

        /**
         * Get an argument.
         * @param int $argId The integer value (from zero) for the arg
         * @param mixed $default The default if it doesn't exist
         * @return mixed
         */
        protected function getArg( $argId = 0, $default = null ) {
                return $this->hasArg( $argId ) ? $this->mArgs[$argId] : $default;
        }

        /**
         * Set the batch size.
         * @param int $s The number of operations to do in a batch
         */
        protected function setBatchSize( $s = 0 ) {
                $this->mBatchSize = $s;

                // If we support $mBatchSize, show the option.
                // Used to be in addDefaultParams, but in order for that to
                // work, subclasses would have to call this function in the constructor
                // before they called parent::__construct which is just weird
                // (and really wasn't done).
                if ( $this->mBatchSize ) {
                        $this->addOption( 'batch-size', 'Run this many operations ' .
                                'per batch, default: ' . $this->mBatchSize, false, true );
                        if ( isset( $this->mParams['batch-size'] ) ) {
                                // This seems a little ugly...
                                $this->mDependantParameters['batch-size'] = $this->mParams['batch-size'];
                        }
                }
        }

        /**
         * Get the script's name
         * @return string
         */
        public function getName() {
                return $this->mSelf;
        }

        /**
         * Return input from stdin.
         * @param int $len The number of bytes to read. If null, just return the handle.
         *   Maintenance::STDIN_ALL returns the full length
         * @return mixed
         */
        protected function getStdin( $len = null ) {
                if ( $len == Maintenance::STDIN_ALL ) {
                        return file_get_contents( 'php://stdin' );
                }
                $f = fopen( 'php://stdin', 'rt' );
                if ( !$len ) {
                        return $f;
                }
                $input = fgets( $f, $len );
                fclose( $f );

                return rtrim( $input );
        }

        /**
         * @return bool
         */
        public function isQuiet() {
                return $this->mQuiet;
        }

        /**
         * Throw some output to the user. Scripts can call this with no fears,
         * as we handle all --quiet stuff here
         * @param string $out The text to show to the user
         * @param mixed $channel Unique identifier for the channel. See function outputChanneled.
         */
        protected function output( $out, $channel = null ) {
                if ( $this->mQuiet ) {
                        return;
                }
                if ( $channel === null ) {
                        $this->cleanupChanneled();
                        print $out;
                } else {
                        $out = preg_replace( '/\n\z/', '', $out );
                        $this->outputChanneled( $out, $channel );
                }
        }

        /**
         * Throw an error to the user. Doesn't respect --quiet, so don't use
         * this for non-error output
         * @param string $err The error to display
         * @param int $die If > 0, go ahead and die out using this int as the code
         */
        protected function error( $err, $die = 0 ) {
                $this->outputChanneled( false );
                if ( PHP_SAPI == 'cli' ) {
                        fwrite( STDERR, $err . "\n" );
                } else {
                        print $err;
                }
                $die = intval( $die );
                if ( $die > 0 ) {
                        die( $die );
                }
        }

        private $atLineStart = true;
        private $lastChannel = null;

        /**
         * Clean up channeled output.  Output a newline if necessary.
         */
        public function cleanupChanneled() {
                if ( !$this->atLineStart ) {
                        print "\n";
                        $this->atLineStart = true;
                }
        }

        /**
         * Message outputter with channeled message support. Messages on the
         * same channel are concatenated, but any intervening messages in another
         * channel start a new line.
         * @param string $msg The message without trailing newline
         * @param string $channel Channel identifier or null for no
         *     channel. Channel comparison uses ===.
         */
        public function outputChanneled( $msg, $channel = null ) {
                if ( $msg === false ) {
                        $this->cleanupChanneled();

                        return;
                }

                // End the current line if necessary
                if ( !$this->atLineStart && $channel !== $this->lastChannel ) {
                        print "\n";
                }

                print $msg;

                $this->atLineStart = false;
                if ( $channel === null ) {
                        // For unchanneled messages, output trailing newline immediately
                        print "\n";
                        $this->atLineStart = true;
                }
                $this->lastChannel = $channel;
        }

        /**
         * Does the script need different DB access? By default, we give Maintenance
         * scripts normal rights to the DB. Sometimes, a script needs admin rights
         * access for a reason and sometimes they want no access. Subclasses should
         * override and return one of the following values, as needed:
         *    Maintenance::DB_NONE  -  For no DB access at all
         *    Maintenance::DB_STD   -  For normal DB access, default
         *    Maintenance::DB_ADMIN -  For admin DB access
         * @return int
         */
        public function getDbType() {
                return Maintenance::DB_STD;
        }

        /**
         * Add the default parameters to the scripts
         */
        protected function addDefaultParams() {

                # Generic (non script dependant) options:

                $this->addOption( 'help', 'Display this help message', false, false, 'h' );
                $this->addOption( 'quiet', 'Whether to supress non-error output', false, false, 'q' );
                $this->addOption( 'conf', 'Location of LocalSettings.php, if not default', false, true );
                $this->addOption( 'wiki', 'For specifying the wiki ID', false, true );
                $this->addOption( 'globals', 'Output globals at the end of processing for debugging' );
                $this->addOption(
                        'memory-limit',
                        'Set a specific memory limit for the script, '
                                . '"max" for no limit or "default" to avoid changing it'
                );
                $this->addOption( 'server', "The protocol and server name to use in URLs, e.g. " .
                        "http://en.wikipedia.org. This is sometimes necessary because " .
                        "server name detection may fail in command line scripts.", false, true );
                $this->addOption( 'profiler', 'Profiler output format (usually "text")', false, true );

                # Save generic options to display them separately in help
                $this->mGenericParameters = $this->mParams;

                # Script dependant options:

                // If we support a DB, show the options
                if ( $this->getDbType() > 0 ) {
                        $this->addOption( 'dbuser', 'The DB user to use for this script', false, true );
                        $this->addOption( 'dbpass', 'The password to use for this script', false, true );
                }

                # Save additional script dependant options to display
                #  them separately in help
                $this->mDependantParameters = array_diff_key( $this->mParams, $this->mGenericParameters );
        }

        /**
         * @since 1.24
         * @return Config
         */
        public function getConfig() {
                if ( $this->config === null ) {
                        $this->config = ConfigFactory::getDefaultInstance()->makeConfig( 'main' );
                }

                return $this->config;
        }

        /**
         * @since 1.24
         * @param Config $config
         */
        public function setConfig( Config $config ) {
                $this->config = $config;
        }

        /**
         * Run a child maintenance script. Pass all of the current arguments
         * to it.
         * @param string $maintClass A name of a child maintenance class
         * @param string $classFile Full path of where the child is
         * @return Maintenance
         */
        public function runChild( $maintClass, $classFile = null ) {
                // Make sure the class is loaded first
                if ( !class_exists( $maintClass ) ) {
                        if ( $classFile ) {
                                require_once $classFile;
                        }
                        if ( !class_exists( $maintClass ) ) {
                                $this->error( "Cannot spawn child: $maintClass" );
                        }
                }

                /**
                 * @var $child Maintenance
                 */
                $child = new $maintClass();
                $child->loadParamsAndArgs( $this->mSelf, $this->mOptions, $this->mArgs );
                if ( !is_null( $this->mDb ) ) {
                        $child->setDB( $this->mDb );
                }

                return $child;
        }

        /**
         * Do some sanity checking and basic setup
         */
        public function setup() {
                global $IP, $wgCommandLineMode, $wgRequestTime;

                # Abort if called from a web server
                if ( isset( $_SERVER ) && isset( $_SERVER['REQUEST_METHOD'] ) ) {
                        $this->error( 'This script must be run from the command line', true );
                }

                if ( $IP === null ) {
                        $this->error( "\$IP not set, aborting!\n" .
                                '(Did you forget to call parent::__construct() in your maintenance script?)', 1 );
                }

                # Make sure we can handle script parameters
                if ( !defined( 'HPHP_VERSION' ) && !ini_get( 'register_argc_argv' ) ) {
                        $this->error( 'Cannot get command line arguments, register_argc_argv is set to false', true );
                }

                // Send PHP warnings and errors to stderr instead of stdout.
                // This aids in diagnosing problems, while keeping messages
                // out of redirected output.
                if ( ini_get( 'display_errors' ) ) {
                        ini_set( 'display_errors', 'stderr' );
                }

                $this->loadParamsAndArgs();
                $this->maybeHelp();

                # Set the memory limit
                # Note we need to set it again later in cache LocalSettings changed it
                $this->adjustMemoryLimit();

                # Set max execution time to 0 (no limit). PHP.net says that
                # "When running PHP from the command line the default setting is 0."
                # But sometimes this doesn't seem to be the case.
                ini_set( 'max_execution_time', 0 );

                $wgRequestTime = microtime( true );

                # Define us as being in MediaWiki
                define( 'MEDIAWIKI', true );

                $wgCommandLineMode = true;

                # Turn off output buffering if it's on
                while ( ob_get_level() > 0 ) {
                        ob_end_flush();
                }

                $this->validateParamsAndArgs();
        }

        /**
         * Normally we disable the memory_limit when running admin scripts.
         * Some scripts may wish to actually set a limit, however, to avoid
         * blowing up unexpectedly. We also support a --memory-limit option,
         * to allow sysadmins to explicitly set one if they'd prefer to override
         * defaults (or for people using Suhosin which yells at you for trying
         * to disable the limits)
         * @return string
         */
        public function memoryLimit() {
                $limit = $this->getOption( 'memory-limit', 'max' );
                $limit = trim( $limit, "\" '" ); // trim quotes in case someone misunderstood
                return $limit;
        }

        /**
         * Adjusts PHP's memory limit to better suit our needs, if needed.
         */
        protected function adjustMemoryLimit() {
                $limit = $this->memoryLimit();
                if ( $limit == 'max' ) {
                        $limit = -1; // no memory limit
                }
                if ( $limit != 'default' ) {
                        ini_set( 'memory_limit', $limit );
                }
        }

        /**
         * Activate the profiler (assuming $wgProfiler is set)
         */
        protected function activateProfiler() {
                global $wgProfiler, $wgProfileLimit, $wgTrxProfilerLimits;

                $output = $this->getOption( 'profiler' );
                if ( !$output ) {
                        return;
                }

                if ( is_array( $wgProfiler ) && isset( $wgProfiler['class'] ) ) {
                        $class = $wgProfiler['class'];
                        $profiler = new $class(
                                array( 'sampling' => 1, 'output' => array( $output ) )
                                        + $wgProfiler
                                        + array( 'threshold' => $wgProfileLimit )
                        );
                        $profiler->setTemplated( true );
                        Profiler::replaceStubInstance( $profiler );
                }

                $trxProfiler = Profiler::instance()->getTransactionProfiler();
                $trxProfiler->setLogger( LoggerFactory::getInstance( 'DBPerformance' ) );
                $trxProfiler->setExpectations( $wgTrxProfilerLimits['Maintenance'], __METHOD__ );
        }

        /**
         * Clear all params and arguments.
         */
        public function clearParamsAndArgs() {
                $this->mOptions = array();
                $this->mArgs = array();
                $this->mInputLoaded = false;
        }

        /**
         * Load params and arguments from a given array
         * of command-line arguments
         *
         * @since 1.27
         * @param array $argv
         */
        public function loadWithArgv( $argv ) {
                $options = array();
                $args = array();
                $this->orderedOptions = array();

                # Parse arguments
                for ( $arg = reset( $argv ); $arg !== false; $arg = next( $argv ) ) {
                        if ( $arg == '--' ) {
                                # End of options, remainder should be considered arguments
                                $arg = next( $argv );
                                while ( $arg !== false ) {
                                        $args[] = $arg;
                                        $arg = next( $argv );
                                }
                                break;
                        } elseif ( substr( $arg, 0, 2 ) == '--' ) {
                                # Long options
                                $option = substr( $arg, 2 );
                                if ( isset( $this->mParams[$option] ) && $this->mParams[$option]['withArg'] ) {
                                        $param = next( $argv );
                                        if ( $param === false ) {
                                                $this->error( "\nERROR: $option parameter needs a value after it\n" );
                                                $this->maybeHelp( true );
                                        }

                                        $this->setParam( $options, $option, $param );
                                } else {
                                        $bits = explode( '=', $option, 2 );
                                        if ( count( $bits ) > 1 ) {
                                                $option = $bits[0];
                                                $param = $bits[1];
                                        } else {
                                                $param = 1;
                                        }

                                        $this->setParam( $options, $option, $param );
                                }
                        } elseif ( $arg == '-' ) {
                                # Lonely "-", often used to indicate stdin or stdout.
                                $args[] = $arg;
                        } elseif ( substr( $arg, 0, 1 ) == '-' ) {
                                # Short options
                                $argLength = strlen( $arg );
                                for ( $p = 1; $p < $argLength; $p++ ) {
                                        $option = $arg[$p];
                                        if ( !isset( $this->mParams[$option] ) && isset( $this->mShortParamsMap[$option] ) ) {
                                                $option = $this->mShortParamsMap[$option];
                                        }

                                        if ( isset( $this->mParams[$option]['withArg'] ) && $this->mParams[$option]['withArg'] ) {
                                                $param = next( $argv );
                                                if ( $param === false ) {
                                                        $this->error( "\nERROR: $option parameter needs a value after it\n" );
                                                        $this->maybeHelp( true );
                                                }
                                                $this->setParam( $options, $option, $param );
                                        } else {
                                                $this->setParam( $options, $option, 1 );
                                        }
                                }
                        } else {
                                $args[] = $arg;
                        }
                }

                $this->mOptions = $options;
                $this->mArgs = $args;
                $this->loadSpecialVars();
                $this->mInputLoaded = true;
        }

        /**
         * Helper function used solely by loadParamsAndArgs
         * to prevent code duplication
         *
         * This sets the param in the options array based on
         * whether or not it can be specified multiple times.
         *
         * @since 1.27
         * @param array $options
         * @param string $option
         * @param mixed $value
         */
        private function setParam( &$options, $option, $value ) {
                $this->orderedOptions[] = array( $option, $value );

                if ( isset( $this->mParams[$option] ) ) {
                        $multi = $this->mParams[$option]['multiOccurrence'];
                        $exists = array_key_exists( $option, $options );
                        if ( $multi && $exists ) {
                                $options[$option][] = $value;
                        } elseif ( $multi ) {
                                $options[$option] = array( $value );
                        } elseif ( !$exists ) {
                                $options[$option] = $value;
                        } else {
                                $this->error( "\nERROR: $option parameter given twice\n" );
                                $this->maybeHelp( true );
                        }
                }
        }

        /**
         * Process command line arguments
         * $mOptions becomes an array with keys set to the option names
         * $mArgs becomes a zero-based array containing the non-option arguments
         *
         * @param string $self The name of the script, if any
         * @param array $opts An array of options, in form of key=>value
         * @param array $args An array of command line arguments
         */
        public function loadParamsAndArgs( $self = null, $opts = null, $args = null ) {
                # If we were given opts or args, set those and return early
                if ( $self ) {
                        $this->mSelf = $self;
                        $this->mInputLoaded = true;
                }
                if ( $opts ) {
                        $this->mOptions = $opts;
                        $this->mInputLoaded = true;
                }
                if ( $args ) {
                        $this->mArgs = $args;
                        $this->mInputLoaded = true;
                }

                # If we've already loaded input (either by user values or from $argv)
                # skip on loading it again. The array_shift() will corrupt values if
                # it's run again and again
                if ( $this->mInputLoaded ) {
                        $this->loadSpecialVars();

                        return;
                }

                global $argv;
                $this->mSelf = $argv[0];
                $this->loadWithArgv( array_slice( $argv, 1 ) );
        }

        /**
         * Run some validation checks on the params, etc
         */
        protected function validateParamsAndArgs() {
                $die = false;
                # Check to make sure we've got all the required options
                foreach ( $this->mParams as $opt => $info ) {
                        if ( $info['require'] && !$this->hasOption( $opt ) ) {
                                $this->error( "Param $opt required!" );
                                $die = true;
                        }
                }
                # Check arg list too
                foreach ( $this->mArgList as $k => $info ) {
                        if ( $info['require'] && !$this->hasArg( $k ) ) {
                                $this->error( 'Argument <' . $info['name'] . '> required!' );
                                $die = true;
                        }
                }

                if ( $die ) {
                        $this->maybeHelp( true );
                }
        }

        /**
         * Handle the special variables that are global to all scripts
         */
        protected function loadSpecialVars() {
                if ( $this->hasOption( 'dbuser' ) ) {
                        $this->mDbUser = $this->getOption( 'dbuser' );
                }
                if ( $this->hasOption( 'dbpass' ) ) {
                        $this->mDbPass = $this->getOption( 'dbpass' );
                }
                if ( $this->hasOption( 'quiet' ) ) {
                        $this->mQuiet = true;
                }
                if ( $this->hasOption( 'batch-size' ) ) {
                        $this->mBatchSize = intval( $this->getOption( 'batch-size' ) );
                }
        }

        /**
         * Maybe show the help.
         * @param bool $force Whether to force the help to show, default false
         */
        protected function maybeHelp( $force = false ) {
                if ( !$force && !$this->hasOption( 'help' ) ) {
                        return;
                }

                $screenWidth = 80; // TODO: Calculate this!
                $tab = "    ";
                $descWidth = $screenWidth - ( 2 * strlen( $tab ) );

                ksort( $this->mParams );
                $this->mQuiet = false;

                // Description ...
                if ( $this->mDescription ) {
                        $this->output( "\n" . $this->mDescription . "\n" );
                }
                $output = "\nUsage: php " . basename( $this->mSelf );

                // ... append parameters ...
                if ( $this->mParams ) {
                        $output .= " [--" . implode( array_keys( $this->mParams ), "|--" ) . "]";
                }

                // ... and append arguments.
                if ( $this->mArgList ) {
                        $output .= ' ';
                        foreach ( $this->mArgList as $k => $arg ) {
                                if ( $arg['require'] ) {
                                        $output .= '<' . $arg['name'] . '>';
                                } else {
                                        $output .= '[' . $arg['name'] . ']';
                                }
                                if ( $k < count( $this->mArgList ) - 1 ) {
                                        $output .= ' ';
                                }
                        }
                }
                $this->output( "$output\n\n" );

                # TODO abstract some repetitive code below

                // Generic parameters
                $this->output( "Generic maintenance parameters:\n" );
                foreach ( $this->mGenericParameters as $par => $info ) {
                        if ( $info['shortName'] !== false ) {
                                $par .= " (-{$info['shortName']})";
                        }
                        $this->output(
                                wordwrap( "$tab--$par: " . $info['desc'], $descWidth,
                                        "\n$tab$tab" ) . "\n"
                        );
                }
                $this->output( "\n" );

                $scriptDependantParams = $this->mDependantParameters;
                if ( count( $scriptDependantParams ) > 0 ) {
                        $this->output( "Script dependant parameters:\n" );
                        // Parameters description
                        foreach ( $scriptDependantParams as $par => $info ) {
                                if ( $info['shortName'] !== false ) {
                                        $par .= " (-{$info['shortName']})";
                                }
                                $this->output(
                                        wordwrap( "$tab--$par: " . $info['desc'], $descWidth,
                                                "\n$tab$tab" ) . "\n"
                                );
                        }
                        $this->output( "\n" );
                }

                // Script specific parameters not defined on construction by
                // Maintenance::addDefaultParams()
                $scriptSpecificParams = array_diff_key(
                        # all script parameters:
                        $this->mParams,
                        # remove the Maintenance default parameters:
                        $this->mGenericParameters,
                        $this->mDependantParameters
                );
                if ( count( $scriptSpecificParams ) > 0 ) {
                        $this->output( "Script specific parameters:\n" );
                        // Parameters description
                        foreach ( $scriptSpecificParams as $par => $info ) {
                                if ( $info['shortName'] !== false ) {
                                        $par .= " (-{$info['shortName']})";
                                }
                                $this->output(
                                        wordwrap( "$tab--$par: " . $info['desc'], $descWidth,
                                                "\n$tab$tab" ) . "\n"
                                );
                        }
                        $this->output( "\n" );
                }

                // Print arguments
                if ( count( $this->mArgList ) > 0 ) {
                        $this->output( "Arguments:\n" );
                        // Arguments description
                        foreach ( $this->mArgList as $info ) {
                                $openChar = $info['require'] ? '<' : '[';
                                $closeChar = $info['require'] ? '>' : ']';
                                $this->output(
                                        wordwrap( "$tab$openChar" . $info['name'] . "$closeChar: " .
                                                $info['desc'], $descWidth, "\n$tab$tab" ) . "\n"
                                );
                        }
                        $this->output( "\n" );
                }

                die( 1 );
        }

        /**
         * Handle some last-minute setup here.
         */
        public function finalSetup() {
                global $wgCommandLineMode, $wgShowSQLErrors, $wgServer;
                global $wgDBadminuser, $wgDBadminpassword;
                global $wgDBuser, $wgDBpassword, $wgDBservers, $wgLBFactoryConf;

                # Turn off output buffering again, it might have been turned on in the settings files
                if ( ob_get_level() ) {
                        ob_end_flush();
                }
                # Same with these
                $wgCommandLineMode = true;

                # Override $wgServer
                if ( $this->hasOption( 'server' ) ) {
                        $wgServer = $this->getOption( 'server', $wgServer );
                }

                # If these were passed, use them
                if ( $this->mDbUser ) {
                        $wgDBadminuser = $this->mDbUser;
                }
                if ( $this->mDbPass ) {
                        $wgDBadminpassword = $this->mDbPass;
                }

                if ( $this->getDbType() == self::DB_ADMIN && isset( $wgDBadminuser ) ) {
                        $wgDBuser = $wgDBadminuser;
                        $wgDBpassword = $wgDBadminpassword;

                        if ( $wgDBservers ) {
                                /**
                                 * @var $wgDBservers array
                                 */
                                foreach ( $wgDBservers as $i => $server ) {
                                        $wgDBservers[$i]['user'] = $wgDBuser;
                                        $wgDBservers[$i]['password'] = $wgDBpassword;
                                }
                        }
                        if ( isset( $wgLBFactoryConf['serverTemplate'] ) ) {
                                $wgLBFactoryConf['serverTemplate']['user'] = $wgDBuser;
                                $wgLBFactoryConf['serverTemplate']['password'] = $wgDBpassword;
                        }
                        LBFactory::destroyInstance();
                }

                // Per-script profiling; useful for debugging
                $this->activateProfiler();

                $this->afterFinalSetup();

                $wgShowSQLErrors = true;

                MediaWiki\suppressWarnings();
                set_time_limit( 0 );
                MediaWiki\restoreWarnings();

                $this->adjustMemoryLimit();
        }

        /**
         * Execute a callback function at the end of initialisation
         */
        protected function afterFinalSetup() {
                if ( defined( 'MW_CMDLINE_CALLBACK' ) ) {
                        call_user_func( MW_CMDLINE_CALLBACK );
                }
        }

        /**
         * Potentially debug globals. Originally a feature only
         * for refreshLinks
         */
        public function globals() {
                if ( $this->hasOption( 'globals' ) ) {
                        print_r( $GLOBALS );
                }
        }

        /**
         * Generic setup for most installs. Returns the location of LocalSettings
         * @return string
         */
        public function loadSettings() {
                global $wgCommandLineMode, $IP;

                if ( isset( $this->mOptions['conf'] ) ) {
                        $settingsFile = $this->mOptions['conf'];
                } elseif ( defined( "MW_CONFIG_FILE" ) ) {
                        $settingsFile = MW_CONFIG_FILE;
                } else {
                        $settingsFile = "$IP/LocalSettings.php";
                }
                if ( isset( $this->mOptions['wiki'] ) ) {
                        $bits = explode( '-', $this->mOptions['wiki'] );
                        if ( count( $bits ) == 1 ) {
                                $bits[] = '';
                        }
                        define( 'MW_DB', $bits[0] );
                        define( 'MW_PREFIX', $bits[1] );
                }

                if ( !is_readable( $settingsFile ) ) {
                        $this->error( "A copy of your installation's LocalSettings.php\n" .
                                "must exist and be readable in the source directory.\n" .
                                "Use --conf to specify it.", true );
                }
                $wgCommandLineMode = true;

                return $settingsFile;
        }

        /**
         * Support function for cleaning up redundant text records
         * @param bool $delete Whether or not to actually delete the records
         * @author Rob Church <robchur@gmail.com>
         */
        public function purgeRedundantText( $delete = true ) {
                # Data should come off the master, wrapped in a transaction
                $dbw = $this->getDB( DB_MASTER );
                $this->beginTransaction( $dbw, __METHOD__ );

                # Get "active" text records from the revisions table
                $this->output( 'Searching for active text records in revisions table...' );
                $res = $dbw->select( 'revision', 'rev_text_id', array(), __METHOD__, array( 'DISTINCT' ) );
                foreach ( $res as $row ) {
                        $cur[] = $row->rev_text_id;
                }
                $this->output( "done.\n" );

                # Get "active" text records from the archive table
                $this->output( 'Searching for active text records in archive table...' );
                $res = $dbw->select( 'archive', 'ar_text_id', array(), __METHOD__, array( 'DISTINCT' ) );
                foreach ( $res as $row ) {
                        # old pre-MW 1.5 records can have null ar_text_id's.
                        if ( $row->ar_text_id !== null ) {
                                $cur[] = $row->ar_text_id;
                        }
                }
                $this->output( "done.\n" );

                # Get the IDs of all text records not in these sets
                $this->output( 'Searching for inactive text records...' );
                $cond = 'old_id NOT IN ( ' . $dbw->makeList( $cur ) . ' )';
                $res = $dbw->select( 'text', 'old_id', array( $cond ), __METHOD__, array( 'DISTINCT' ) );
                $old = array();
                foreach ( $res as $row ) {
                        $old[] = $row->old_id;
                }
                $this->output( "done.\n" );

                # Inform the user of what we're going to do
                $count = count( $old );
                $this->output( "$count inactive items found.\n" );

                # Delete as appropriate
                if ( $delete && $count ) {
                        $this->output( 'Deleting...' );
                        $dbw->delete( 'text', array( 'old_id' => $old ), __METHOD__ );
                        $this->output( "done.\n" );
                }

                # Done
                $this->commitTransaction( $dbw, __METHOD__ );
        }

        /**
         * Get the maintenance directory.
         * @return string
         */
        protected function getDir() {
                return __DIR__;
        }

        /**
         * Returns a database to be used by current maintenance script. It can be set by setDB().
         * If not set, wfGetDB() will be used.
         * This function has the same parameters as wfGetDB()
         *
         * @param integer $db DB index (DB_SLAVE/DB_MASTER)
         * @param array $groups; default: empty array
         * @param string|bool $wiki; default: current wiki
         * @return IDatabase
         */
        protected function getDB( $db, $groups = array(), $wiki = false ) {
                if ( is_null( $this->mDb ) ) {
                        return wfGetDB( $db, $groups, $wiki );
                } else {
                        return $this->mDb;
                }
        }

        /**
         * Sets database object to be returned by getDB().
         *
         * @param IDatabase $db Database object to be used
         */
        public function setDB( IDatabase $db ) {
                $this->mDb = $db;
        }

        /**
         * Begin a transcation on a DB
         *
         * This method makes it clear that begin() is called from a maintenance script,
         * which has outermost scope. This is safe, unlike $dbw->begin() called in other places.
         *
         * @param IDatabase $dbw
         * @param string $fname Caller name
         * @since 1.27
         */
        protected function beginTransaction( IDatabase $dbw, $fname ) {
                $dbw->begin( $fname );
        }

        /**
         * Commit a transcation on a DB
         *
         * This method makes it clear that commit() is called from a maintenance script,
         * which has outermost scope. This is safe, unlike $dbw->commit() called in other places.
         *
         * @param IDatabase $dbw
         * @param string $fname Caller name
         * @since 1.27
         */
        protected function commitTransaction( IDatabase $dbw, $fname ) {
                $dbw->commit( $fname );
        }

        /**
         * Rollback a transcation on a DB
         *
         * This method makes it clear that rollback() is called from a maintenance script,
         * which has outermost scope. This is safe, unlike $dbw->rollback() called in other places.
         *
         * @param IDatabase $dbw
         * @param string $fname Caller name
         * @since 1.27
         */
        protected function rollbackTransaction( IDatabase $dbw, $fname ) {
                $dbw->rollback( $fname );
        }

        /**
         * Lock the search index
         * @param DatabaseBase &$db
         */
        private function lockSearchindex( $db ) {
                $write = array( 'searchindex' );
                $read = array(
                        'page',
                        'revision',
                        'text',
                        'interwiki',
                        'l10n_cache',
                        'user',
                        'page_restrictions'
                );
                $db->lockTables( $read, $write, __CLASS__ . '::' . __METHOD__ );
        }

        /**
         * Unlock the tables
         * @param DatabaseBase &$db
         */
        private function unlockSearchindex( $db ) {
                $db->unlockTables( __CLASS__ . '::' . __METHOD__ );
        }

        /**
         * Unlock and lock again
         * Since the lock is low-priority, queued reads will be able to complete
         * @param DatabaseBase &$db
         */
        private function relockSearchindex( $db ) {
                $this->unlockSearchindex( $db );
                $this->lockSearchindex( $db );
        }

        /**
         * Perform a search index update with locking
         * @param int $maxLockTime The maximum time to keep the search index locked.
         * @param string $callback The function that will update the function.
         * @param DatabaseBase $dbw
         * @param array $results
         */
        public function updateSearchIndex( $maxLockTime, $callback, $dbw, $results ) {
                $lockTime = time();

                # Lock searchindex
                if ( $maxLockTime ) {
                        $this->output( "   --- Waiting for lock ---" );
                        $this->lockSearchindex( $dbw );
                        $lockTime = time();
                        $this->output( "\n" );
                }

                # Loop through the results and do a search update
                foreach ( $results as $row ) {
                        # Allow reads to be processed
                        if ( $maxLockTime && time() > $lockTime + $maxLockTime ) {
                                $this->output( "    --- Relocking ---" );
                                $this->relockSearchindex( $dbw );
                                $lockTime = time();
                                $this->output( "\n" );
                        }
                        call_user_func( $callback, $dbw, $row );
                }

                # Unlock searchindex
                if ( $maxLockTime ) {
                        $this->output( "    --- Unlocking --" );
                        $this->unlockSearchindex( $dbw );
                        $this->output( "\n" );
                }
        }

        /**
         * Update the searchindex table for a given pageid
         * @param DatabaseBase $dbw A database write handle
         * @param int $pageId The page ID to update.
         * @return null|string
         */
        public function updateSearchIndexForPage( $dbw, $pageId ) {
                // Get current revision
                $rev = Revision::loadFromPageId( $dbw, $pageId );
                $title = null;
                if ( $rev ) {
                        $titleObj = $rev->getTitle();
                        $title = $titleObj->getPrefixedDBkey();
                        $this->output( "$title..." );
                        # Update searchindex
                        $u = new SearchUpdate( $pageId, $titleObj->getText(), $rev->getContent() );
                        $u->doUpdate();
                        $this->output( "\n" );
                }

                return $title;
        }

        /**
         * Wrapper for posix_isatty()
         * We default as considering stdin a tty (for nice readline methods)
         * but treating stout as not a tty to avoid color codes
         *
         * @param mixed $fd File descriptor
         * @return bool
         */
        public static function posix_isatty( $fd ) {
                if ( !function_exists( 'posix_isatty' ) ) {
                        return !$fd;
                } else {
                        return posix_isatty( $fd );
                }
        }

        /**
         * Prompt the console for input
         * @param string $prompt What to begin the line with, like '> '
         * @return string Response
         */
        public static function readconsole( $prompt = '> ' ) {
                static $isatty = null;
                if ( is_null( $isatty ) ) {
                        $isatty = self::posix_isatty( 0 /*STDIN*/ );
                }

                if ( $isatty && function_exists( 'readline' ) ) {
                        $resp = readline( $prompt );
                        if ( $resp === null ) {
                                // Workaround for https://github.com/facebook/hhvm/issues/4776
                                return false;
                        } else {
                                return $resp;
                        }
                } else {
                        if ( $isatty ) {
                                $st = self::readlineEmulation( $prompt );
                        } else {
                                if ( feof( STDIN ) ) {
                                        $st = false;
                                } else {
                                        $st = fgets( STDIN, 1024 );
                                }
                        }
                        if ( $st === false ) {
                                return false;
                        }
                        $resp = trim( $st );

                        return $resp;
                }
        }

        /**
         * Emulate readline()
         * @param string $prompt What to begin the line with, like '> '
         * @return string
         */
        private static function readlineEmulation( $prompt ) {
                $bash = Installer::locateExecutableInDefaultPaths( array( 'bash' ) );
                if ( !wfIsWindows() && $bash ) {
                        $retval = false;
                        $encPrompt = wfEscapeShellArg( $prompt );
                        $command = "read -er -p $encPrompt && echo \"\$REPLY\"";
                        $encCommand = wfEscapeShellArg( $command );
                        $line = wfShellExec( "$bash -c $encCommand", $retval, array(), array( 'walltime' => 0 ) );

                        if ( $retval == 0 ) {
                                return $line;
                        } elseif ( $retval == 127 ) {
                                // Couldn't execute bash even though we thought we saw it.
                                // Shell probably spit out an error message, sorry :(
                                // Fall through to fgets()...
                        } else {
                                // EOF/ctrl+D
                                return false;
                        }
                }

                // Fallback... we'll have no editing controls, EWWW
                if ( feof( STDIN ) ) {
                        return false;
                }
                print $prompt;

                return fgets( STDIN, 1024 );
        }
}

/**
 * Fake maintenance wrapper, mostly used for the web installer/updater
 */
class FakeMaintenance extends Maintenance {
        protected $mSelf = "FakeMaintenanceScript";

        public function execute() {
                return;
        }
}

/**
 * Class for scripts that perform database maintenance and want to log the
 * update in `updatelog` so we can later skip it
 */
abstract class LoggedUpdateMaintenance extends Maintenance {
        public function __construct() {
                parent::__construct();
                $this->addOption( 'force', 'Run the update even if it was completed already' );
                $this->setBatchSize( 200 );
        }

        public function execute() {
                $db = $this->getDB( DB_MASTER );
                $key = $this->getUpdateKey();

                if ( !$this->hasOption( 'force' )
                        && $db->selectRow( 'updatelog', '1', array( 'ul_key' => $key ), __METHOD__ )
                ) {
                        $this->output( "..." . $this->updateSkippedMessage() . "\n" );

                        return true;
                }

                if ( !$this->doDBUpdates() ) {
                        return false;
                }

                if ( $db->insert( 'updatelog', array( 'ul_key' => $key ), __METHOD__, 'IGNORE' ) ) {
                        return true;
                } else {
                        $this->output( $this->updatelogFailedMessage() . "\n" );

                        return false;
                }
        }

        /**
         * Message to show that the update was done already and was just skipped
         * @return string
         */
        protected function updateSkippedMessage() {
                $key = $this->getUpdateKey();

                return "Update '{$key}' already logged as completed.";
        }

        /**
         * Message to show that the update log was unable to log the completion of this update
         * @return string
         */
        protected function updatelogFailedMessage() {
                $key = $this->getUpdateKey();

                return "Unable to log update '{$key}' as completed.";
        }

        /**
         * Do the actual work. All child classes will need to implement this.
         * Return true to log the update as done or false (usually on failure).
         * @return bool
         */
        abstract protected function doDBUpdates();

        /**
         * Get the update key name to go in the update log table
         * @return string
         */
        abstract protected function getUpdateKey();
}