Move ILoadBalancer to Rdbms namespace

[mediawiki.git] / includes / MagicWord.php

<?php
/**
 * See docs/magicword.txt.
 *
 * 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 Parser
 */

/**
 * This class encapsulates "magic words" such as "#redirect", __NOTOC__, etc.
 *
 * @par Usage:
 * @code
 *     if (MagicWord::get( 'redirect' )->match( $text ) ) {
 *       // some code
 *     }
 * @endcode
 *
 * Possible future improvements:
 *   * Simultaneous searching for a number of magic words
 *   * MagicWord::$mObjects in shared memory
 *
 * Please avoid reading the data out of one of these objects and then writing
 * special case code. If possible, add another match()-like function here.
 *
 * To add magic words in an extension, use $magicWords in a file listed in
 * $wgExtensionMessagesFiles[].
 *
 * @par Example:
 * @code
 * $magicWords = [];
 *
 * $magicWords['en'] = [
 *      'magicwordkey' => [ 0, 'case_insensitive_magic_word' ],
 *      'magicwordkey2' => [ 1, 'CASE_sensitive_magic_word2' ],
 * ];
 * @endcode
 *
 * For magic words which are also Parser variables, add a MagicWordwgVariableIDs
 * hook. Use string keys.
 *
 * @ingroup Parser
 */
class MagicWord {
        /**#@-*/

        /** @var int */
        public $mId;

        /** @var array */
        public $mSynonyms;

        /** @var bool */
        public $mCaseSensitive;

        /** @var string */
        private $mRegex = '';

        /** @var string */
        private $mRegexStart = '';

        /** @var string */
        private $mRegexStartToEnd = '';

        /** @var string */
        private $mBaseRegex = '';

        /** @var string */
        private $mVariableRegex = '';

        /** @var string */
        private $mVariableStartToEndRegex = '';

        /** @var bool */
        private $mModified = false;

        /** @var bool */
        private $mFound = false;

        public static $mVariableIDsInitialised = false;
        public static $mVariableIDs = [
                '!',
                'currentmonth',
                'currentmonth1',
                'currentmonthname',
                'currentmonthnamegen',
                'currentmonthabbrev',
                'currentday',
                'currentday2',
                'currentdayname',
                'currentyear',
                'currenttime',
                'currenthour',
                'localmonth',
                'localmonth1',
                'localmonthname',
                'localmonthnamegen',
                'localmonthabbrev',
                'localday',
                'localday2',
                'localdayname',
                'localyear',
                'localtime',
                'localhour',
                'numberofarticles',
                'numberoffiles',
                'numberofedits',
                'articlepath',
                'pageid',
                'sitename',
                'server',
                'servername',
                'scriptpath',
                'stylepath',
                'pagename',
                'pagenamee',
                'fullpagename',
                'fullpagenamee',
                'namespace',
                'namespacee',
                'namespacenumber',
                'currentweek',
                'currentdow',
                'localweek',
                'localdow',
                'revisionid',
                'revisionday',
                'revisionday2',
                'revisionmonth',
                'revisionmonth1',
                'revisionyear',
                'revisiontimestamp',
                'revisionuser',
                'revisionsize',
                'subpagename',
                'subpagenamee',
                'talkspace',
                'talkspacee',
                'subjectspace',
                'subjectspacee',
                'talkpagename',
                'talkpagenamee',
                'subjectpagename',
                'subjectpagenamee',
                'numberofusers',
                'numberofactiveusers',
                'numberofpages',
                'currentversion',
                'rootpagename',
                'rootpagenamee',
                'basepagename',
                'basepagenamee',
                'currenttimestamp',
                'localtimestamp',
                'directionmark',
                'contentlanguage',
                'pagelanguage',
                'numberofadmins',
                'cascadingsources',
        ];

        /* Array of caching hints for ParserCache */
        public static $mCacheTTLs = [
                'currentmonth' => 86400,
                'currentmonth1' => 86400,
                'currentmonthname' => 86400,
                'currentmonthnamegen' => 86400,
                'currentmonthabbrev' => 86400,
                'currentday' => 3600,
                'currentday2' => 3600,
                'currentdayname' => 3600,
                'currentyear' => 86400,
                'currenttime' => 3600,
                'currenthour' => 3600,
                'localmonth' => 86400,
                'localmonth1' => 86400,
                'localmonthname' => 86400,
                'localmonthnamegen' => 86400,
                'localmonthabbrev' => 86400,
                'localday' => 3600,
                'localday2' => 3600,
                'localdayname' => 3600,
                'localyear' => 86400,
                'localtime' => 3600,
                'localhour' => 3600,
                'numberofarticles' => 3600,
                'numberoffiles' => 3600,
                'numberofedits' => 3600,
                'currentweek' => 3600,
                'currentdow' => 3600,
                'localweek' => 3600,
                'localdow' => 3600,
                'numberofusers' => 3600,
                'numberofactiveusers' => 3600,
                'numberofpages' => 3600,
                'currentversion' => 86400,
                'currenttimestamp' => 3600,
                'localtimestamp' => 3600,
                'pagesinnamespace' => 3600,
                'numberofadmins' => 3600,
                'numberingroup' => 3600,
        ];

        public static $mDoubleUnderscoreIDs = [
                'notoc',
                'nogallery',
                'forcetoc',
                'toc',
                'noeditsection',
                'newsectionlink',
                'nonewsectionlink',
                'hiddencat',
                'index',
                'noindex',
                'staticredirect',
                'notitleconvert',
                'nocontentconvert',
        ];

        public static $mSubstIDs = [
                'subst',
                'safesubst',
        ];

        public static $mObjects = [];
        public static $mDoubleUnderscoreArray = null;

        /**#@-*/

        public function __construct( $id = 0, $syn = [], $cs = false ) {
                $this->mId = $id;
                $this->mSynonyms = (array)$syn;
                $this->mCaseSensitive = $cs;
        }

        /**
         * Factory: creates an object representing an ID
         *
         * @param int $id
         *
         * @return MagicWord
         */
        public static function &get( $id ) {
                if ( !isset( self::$mObjects[$id] ) ) {
                        $mw = new MagicWord();
                        $mw->load( $id );
                        self::$mObjects[$id] = $mw;
                }
                return self::$mObjects[$id];
        }

        /**
         * Get an array of parser variable IDs
         *
         * @return array
         */
        public static function getVariableIDs() {
                if ( !self::$mVariableIDsInitialised ) {
                        # Get variable IDs
                        Hooks::run( 'MagicWordwgVariableIDs', [ &self::$mVariableIDs ] );
                        self::$mVariableIDsInitialised = true;
                }
                return self::$mVariableIDs;
        }

        /**
         * Get an array of parser substitution modifier IDs
         * @return array
         */
        public static function getSubstIDs() {
                return self::$mSubstIDs;
        }

        /**
         * Allow external reads of TTL array
         *
         * @param int $id
         * @return int
         */
        public static function getCacheTTL( $id ) {
                if ( array_key_exists( $id, self::$mCacheTTLs ) ) {
                        return self::$mCacheTTLs[$id];
                } else {
                        return -1;
                }
        }

        /**
         * Get a MagicWordArray of double-underscore entities
         *
         * @return MagicWordArray
         */
        public static function getDoubleUnderscoreArray() {
                if ( is_null( self::$mDoubleUnderscoreArray ) ) {
                        Hooks::run( 'GetDoubleUnderscoreIDs', [ &self::$mDoubleUnderscoreIDs ] );
                        self::$mDoubleUnderscoreArray = new MagicWordArray( self::$mDoubleUnderscoreIDs );
                }
                return self::$mDoubleUnderscoreArray;
        }

        /**
         * Clear the self::$mObjects variable
         * For use in parser tests
         */
        public static function clearCache() {
                self::$mObjects = [];
        }

        /**
         * Initialises this object with an ID
         *
         * @param int $id
         * @throws MWException
         */
        public function load( $id ) {
                global $wgContLang;
                $this->mId = $id;
                $wgContLang->getMagic( $this );
                if ( !$this->mSynonyms ) {
                        $this->mSynonyms = [ 'brionmademeputthishere' ];
                        throw new MWException( "Error: invalid magic word '$id'" );
                }
        }

        /**
         * Preliminary initialisation
         * @private
         */
        public function initRegex() {
                // Sort the synonyms by length, descending, so that the longest synonym
                // matches in precedence to the shortest
                $synonyms = $this->mSynonyms;
                usort( $synonyms, [ $this, 'compareStringLength' ] );

                $escSyn = [];
                foreach ( $synonyms as $synonym ) {
                        // In case a magic word contains /, like that's going to happen;)
                        $escSyn[] = preg_quote( $synonym, '/' );
                }
                $this->mBaseRegex = implode( '|', $escSyn );

                $case = $this->mCaseSensitive ? '' : 'iu';
                $this->mRegex = "/{$this->mBaseRegex}/{$case}";
                $this->mRegexStart = "/^(?:{$this->mBaseRegex})/{$case}";
                $this->mRegexStartToEnd = "/^(?:{$this->mBaseRegex})$/{$case}";
                $this->mVariableRegex = str_replace( "\\$1", "(.*?)", $this->mRegex );
                $this->mVariableStartToEndRegex = str_replace( "\\$1", "(.*?)",
                        "/^(?:{$this->mBaseRegex})$/{$case}" );
        }

        /**
         * A comparison function that returns -1, 0 or 1 depending on whether the
         * first string is longer, the same length or shorter than the second
         * string.
         *
         * @param string $s1
         * @param string $s2
         *
         * @return int
         */
        public function compareStringLength( $s1, $s2 ) {
                $l1 = strlen( $s1 );
                $l2 = strlen( $s2 );
                if ( $l1 < $l2 ) {
                        return 1;
                } elseif ( $l1 > $l2 ) {
                        return -1;
                } else {
                        return 0;
                }
        }

        /**
         * Gets a regex representing matching the word
         *
         * @return string
         */
        public function getRegex() {
                if ( $this->mRegex == '' ) {
                        $this->initRegex();
                }
                return $this->mRegex;
        }

        /**
         * Gets the regexp case modifier to use, i.e. i or nothing, to be used if
         * one is using MagicWord::getBaseRegex(), otherwise it'll be included in
         * the complete expression
         *
         * @return string
         */
        public function getRegexCase() {
                if ( $this->mRegex === '' ) {
                        $this->initRegex();
                }

                return $this->mCaseSensitive ? '' : 'iu';
        }

        /**
         * Gets a regex matching the word, if it is at the string start
         *
         * @return string
         */
        public function getRegexStart() {
                if ( $this->mRegex == '' ) {
                        $this->initRegex();
                }
                return $this->mRegexStart;
        }

        /**
         * Gets a regex matching the word from start to end of a string
         *
         * @return string
         * @since 1.23
         */
        public function getRegexStartToEnd() {
                if ( $this->mRegexStartToEnd == '' ) {
                        $this->initRegex();
                }
                return $this->mRegexStartToEnd;
        }

        /**
         * regex without the slashes and what not
         *
         * @return string
         */
        public function getBaseRegex() {
                if ( $this->mRegex == '' ) {
                        $this->initRegex();
                }
                return $this->mBaseRegex;
        }

        /**
         * Returns true if the text contains the word
         *
         * @param string $text
         *
         * @return bool
         */
        public function match( $text ) {
                return (bool)preg_match( $this->getRegex(), $text );
        }

        /**
         * Returns true if the text starts with the word
         *
         * @param string $text
         *
         * @return bool
         */
        public function matchStart( $text ) {
                return (bool)preg_match( $this->getRegexStart(), $text );
        }

        /**
         * Returns true if the text matched the word
         *
         * @param string $text
         *
         * @return bool
         * @since 1.23
         */
        public function matchStartToEnd( $text ) {
                return (bool)preg_match( $this->getRegexStartToEnd(), $text );
        }

        /**
         * Returns NULL if there's no match, the value of $1 otherwise
         * The return code is the matched string, if there's no variable
         * part in the regex and the matched variable part ($1) if there
         * is one.
         *
         * @param string $text
         *
         * @return string
         */
        public function matchVariableStartToEnd( $text ) {
                $matches = [];
                $matchcount = preg_match( $this->getVariableStartToEndRegex(), $text, $matches );
                if ( $matchcount == 0 ) {
                        return null;
                } else {
                        # multiple matched parts (variable match); some will be empty because of
                        # synonyms. The variable will be the second non-empty one so remove any
                        # blank elements and re-sort the indices.
                        # See also bug 6526

                        $matches = array_values( array_filter( $matches ) );

                        if ( count( $matches ) == 1 ) {
                                return $matches[0];
                        } else {
                                return $matches[1];
                        }
                }
        }

        /**
         * Returns true if the text matches the word, and alters the
         * input string, removing all instances of the word
         *
         * @param string $text
         *
         * @return bool
         */
        public function matchAndRemove( &$text ) {
                $this->mFound = false;
                $text = preg_replace_callback(
                        $this->getRegex(),
                        [ $this, 'pregRemoveAndRecord' ],
                        $text
                );

                return $this->mFound;
        }

        /**
         * @param string $text
         * @return bool
         */
        public function matchStartAndRemove( &$text ) {
                $this->mFound = false;
                $text = preg_replace_callback(
                        $this->getRegexStart(),
                        [ $this, 'pregRemoveAndRecord' ],
                        $text
                );

                return $this->mFound;
        }

        /**
         * Used in matchAndRemove()
         *
         * @return string
         */
        public function pregRemoveAndRecord() {
                $this->mFound = true;
                return '';
        }

        /**
         * Replaces the word with something else
         *
         * @param string $replacement
         * @param string $subject
         * @param int $limit
         *
         * @return string
         */
        public function replace( $replacement, $subject, $limit = -1 ) {
                $res = preg_replace(
                        $this->getRegex(),
                        StringUtils::escapeRegexReplacement( $replacement ),
                        $subject,
                        $limit
                );
                $this->mModified = $res !== $subject;
                return $res;
        }

        /**
         * Variable handling: {{SUBST:xxx}} style words
         * Calls back a function to determine what to replace xxx with
         * Input word must contain $1
         *
         * @param string $text
         * @param callable $callback
         *
         * @return string
         */
        public function substituteCallback( $text, $callback ) {
                $res = preg_replace_callback( $this->getVariableRegex(), $callback, $text );
                $this->mModified = $res !== $text;
                return $res;
        }

        /**
         * Matches the word, where $1 is a wildcard
         *
         * @return string
         */
        public function getVariableRegex() {
                if ( $this->mVariableRegex == '' ) {
                        $this->initRegex();
                }
                return $this->mVariableRegex;
        }

        /**
         * Matches the entire string, where $1 is a wildcard
         *
         * @return string
         */
        public function getVariableStartToEndRegex() {
                if ( $this->mVariableStartToEndRegex == '' ) {
                        $this->initRegex();
                }
                return $this->mVariableStartToEndRegex;
        }

        /**
         * Accesses the synonym list directly
         *
         * @param int $i
         *
         * @return string
         */
        public function getSynonym( $i ) {
                return $this->mSynonyms[$i];
        }

        /**
         * @return array
         */
        public function getSynonyms() {
                return $this->mSynonyms;
        }

        /**
         * Returns true if the last call to replace() or substituteCallback()
         * returned a modified text, otherwise false.
         *
         * @return bool
         */
        public function getWasModified() {
                return $this->mModified;
        }

        /**
         * $magicarr is an associative array of (magic word ID => replacement)
         * This method uses the php feature to do several replacements at the same time,
         * thereby gaining some efficiency. The result is placed in the out variable
         * $result. The return value is true if something was replaced.
         * @deprecated since 1.25, unused
         *
         * @param array $magicarr
         * @param string $subject
         * @param string $result
         *
         * @return bool
         */
        public function replaceMultiple( $magicarr, $subject, &$result ) {
                wfDeprecated( __METHOD__, '1.25' );
                $search = [];
                $replace = [];
                foreach ( $magicarr as $id => $replacement ) {
                        $mw = MagicWord::get( $id );
                        $search[] = $mw->getRegex();
                        $replace[] = $replacement;
                }

                $result = preg_replace( $search, $replace, $subject );
                return $result !== $subject;
        }

        /**
         * Adds all the synonyms of this MagicWord to an array, to allow quick
         * lookup in a list of magic words
         *
         * @param array $array
         * @param string $value
         */
        public function addToArray( &$array, $value ) {
                global $wgContLang;
                foreach ( $this->mSynonyms as $syn ) {
                        $array[$wgContLang->lc( $syn )] = $value;
                }
        }

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

        /**
         * @return int
         */
        public function getId() {
                return $this->mId;
        }
}