wikimedia/mediawiki-core

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includes/title/MediaWikiTitleCodec.php

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<?php
/**
 * A codec for MediaWiki page titles.
 *
 * 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
 * @author Daniel Kinzler
 */

namespace MediaWiki\Title;

use InvalidArgumentException;
use Language;
use LogicException;
use MediaWiki\Cache\GenderCache;
use MediaWiki\Interwiki\InterwikiLookup;
use MediaWiki\Linker\LinkTarget;
use MediaWiki\Message\Message;
use MediaWiki\Page\PageReference;
use MediaWiki\Parser\Sanitizer;
use Wikimedia\IPUtils;

/**
 * A codec for MediaWiki page titles.
 *
 * @note Normalization and validation is applied while parsing, not when formatting.
 * It's possible to construct a TitleValue with an invalid title, and use MediaWikiTitleCodec
 * to generate an (invalid) title string from it. TitleValues should be constructed only
 * via parseTitle() or from a (semi)trusted source, such as the database.
 *
 * @see https://www.mediawiki.org/wiki/Requests_for_comment/TitleValue
 * @since 1.23
 */
class MediaWikiTitleCodec implements TitleFormatter, TitleParser {
    /** @var Language */
    protected $language;

    /** @var GenderCache */
    protected $genderCache;

    /** @var string[] */
    protected $localInterwikis;

    /** @var InterwikiLookup */
    protected $interwikiLookup;

    /** @var NamespaceInfo */
    protected $nsInfo;

    /**
     * The code here can throw MalformedTitleException, which cannot be created in
     * unit tests (see T281935). Until that changes, we use this helper callback
     * that can be overridden in unit tests to return a mock instead.
     *
     * @var callable
     */
    private $createMalformedTitleException;

    /**
     * @param Language $language The language object to use for localizing namespace names,
     *   capitalization, etc.
     * @param GenderCache $genderCache The gender cache for generating gendered namespace names
     * @param string[]|string $localInterwikis
     * @param InterwikiLookup $interwikiLookup
     * @param NamespaceInfo $nsInfo
     */
    public function __construct(
        Language $language,
        GenderCache $genderCache,
        $localInterwikis,
        InterwikiLookup $interwikiLookup,
        NamespaceInfo $nsInfo
    ) {
        $this->language = $language;
        $this->genderCache = $genderCache;
        $this->localInterwikis = (array)$localInterwikis;
        $this->interwikiLookup = $interwikiLookup;
        $this->nsInfo = $nsInfo;

        // Default callback is to return a real MalformedTitleException,
        // callback signature matches constructor
        $this->createMalformedTitleException = static function (
            $errorMessage,
            $titleText = null,
            $errorMessageParameters = []
        ): MalformedTitleException {
            return new MalformedTitleException( $errorMessage, $titleText, $errorMessageParameters );
        };
    }

    /**
     * @internal
     * @param callable $callback
     */
    public function overrideCreateMalformedTitleExceptionCallback( callable $callback ) {
        // @codeCoverageIgnoreStart
        if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
            throw new LogicException( __METHOD__ . ' can only be used in tests' );
        }
        // @codeCoverageIgnoreEnd
        $this->createMalformedTitleException = $callback;
    }

    /**
     * @see TitleFormatter::getNamespaceName()
     *
     * @param int $namespace
     * @param string $text
     *
     * @throws InvalidArgumentException If the namespace is invalid
     * @return string Namespace name with underscores (not spaces), e.g. 'User_talk'
     */
    public function getNamespaceName( $namespace, $text ) {
        if ( $this->language->needsGenderDistinction() &&
            $this->nsInfo->hasGenderDistinction( $namespace )
        ) {
            // NOTE: we are assuming here that the title text is a user name!
            $gender = $this->genderCache->getGenderOf( $text, __METHOD__ );
            $name = $this->language->getGenderNsText( $namespace, $gender );
        } else {
            $name = $this->language->getNsText( $namespace );
        }

        if ( $name === false ) {
            throw new InvalidArgumentException( 'Unknown namespace ID: ' . $namespace );
        }

        return $name;
    }

    /**
     * @see TitleFormatter::formatTitle()
     *
     * @param int|false $namespace The namespace ID (or false, if the namespace should be ignored)
     * @param string $text The page title. Should be valid. Only minimal normalization is applied.
     *        Underscores will be replaced.
     * @param string $fragment The fragment name (may be empty).
     * @param string $interwiki The interwiki name (may be empty).
     *
     * @throws InvalidArgumentException If the namespace is invalid
     * @return string
     */
    public function formatTitle( $namespace, $text, $fragment = '', $interwiki = '' ) {
        $out = '';
        if ( $interwiki !== '' ) {
            $out = $interwiki . ':';
        }

        if ( $namespace != 0 ) {
            try {
                $nsName = $this->getNamespaceName( $namespace, $text );
            } catch ( InvalidArgumentException $e ) {
                // See T165149. Awkward, but better than erroneously linking to the main namespace.
                $nsName = $this->language->getNsText( NS_SPECIAL ) . ":Badtitle/NS{$namespace}";
            }

            $out .= $nsName . ':';
        }
        $out .= $text;

        if ( $fragment !== '' ) {
            $out .= '#' . $fragment;
        }

        $out = str_replace( '_', ' ', $out );

        return $out;
    }

    /**
     * Parses the given text and constructs a TitleValue.
     *
     * @param string $text The text to parse
     * @param int $defaultNamespace Namespace to assume by default (usually NS_MAIN)
     *
     * @throws MalformedTitleException
     * @return TitleValue
     */
    public function parseTitle( $text, $defaultNamespace = NS_MAIN ) {
        // Convert things like &eacute; &#257; or &#x3017; into normalized (T16952) text
        $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );

        // NOTE: this is an ugly kludge that allows this class to share the
        // code for parsing with the old Title class. The parser code should
        // be refactored to avoid this.
        $parts = $this->splitTitleString( $filteredText, $defaultNamespace );

        return new TitleValue(
            $parts['namespace'],
            $parts['dbkey'],
            $parts['fragment'],
            $parts['interwiki']
        );
    }

    /**
     * Given a namespace and title, return a TitleValue if valid, or null if invalid.
     *
     * @param int $namespace
     * @param string $text
     * @param string $fragment
     * @param string $interwiki
     *
     * @return TitleValue|null
     */
    public function makeTitleValueSafe( $namespace, $text, $fragment = '', $interwiki = '' ) {
        if ( !$this->nsInfo->exists( $namespace ) ) {
            return null;
        }

        $canonicalNs = $this->nsInfo->getCanonicalName( $namespace );
        $fullText = $canonicalNs == '' ? $text : "$canonicalNs:$text";
        if ( strval( $interwiki ) != '' ) {
            $fullText = "$interwiki:$fullText";
        }
        if ( strval( $fragment ) != '' ) {
            $fullText .= '#' . $fragment;
        }

        try {
            $parts = $this->splitTitleString( $fullText );
        } catch ( MalformedTitleException $e ) {
            return null;
        }

        return new TitleValue(
            $parts['namespace'], $parts['dbkey'], $parts['fragment'], $parts['interwiki'] );
    }

    /**
     * @see TitleFormatter::getText()
     *
     * @param LinkTarget|PageReference $title
     *
     * @return string
     */
    public function getText( $title ) {
        if ( $title instanceof LinkTarget ) {
            return $title->getText();
        } elseif ( $title instanceof PageReference ) {
            return strtr( $title->getDBKey(), '_', ' ' );
        } else {
            throw new InvalidArgumentException( '$title has invalid type: ' . get_class( $title ) );
        }
    }

    /**
     * @see TitleFormatter::getText()
     *
     * @param LinkTarget|PageReference $title
     *
     * @return string
     * @suppress PhanUndeclaredProperty
     */
    public function getPrefixedText( $title ) {
        if ( $title instanceof LinkTarget ) {
            if ( !isset( $title->prefixedText ) ) {
                $title->prefixedText = $this->formatTitle(
                    $title->getNamespace(),
                    $title->getText(),
                    '',
                    $title->getInterwiki()
                );
            }
            return $title->prefixedText;
        } elseif ( $title instanceof PageReference ) {
            $title->assertWiki( PageReference::LOCAL );
            return $this->formatTitle(
                $title->getNamespace(),
                $this->getText( $title )
            );
        } else {
            throw new InvalidArgumentException( '$title has invalid type: ' . get_class( $title ) );
        }
    }

    /**
     * @since 1.27
     * @see TitleFormatter::getPrefixedDBkey()
     * @param LinkTarget|PageReference $target
     * @return string
     */
    public function getPrefixedDBkey( $target ) {
        if ( $target instanceof LinkTarget ) {
            return strtr( $this->formatTitle(
                $target->getNamespace(),
                $target->getDBkey(),
                '',
                $target->getInterwiki()
            ), ' ', '_' );
        } elseif ( $target instanceof PageReference ) {
            $target->assertWiki( PageReference::LOCAL );
            return strtr( $this->formatTitle(
                $target->getNamespace(),
                $target->getDBkey()
            ), ' ', '_' );
        } else {
            throw new InvalidArgumentException( '$title has invalid type: ' . get_class( $target ) );
        }
    }

    /**
     * @see TitleFormatter::getText()
     *
     * @param LinkTarget|PageReference $title
     *
     * @return string
     */
    public function getFullText( $title ) {
        if ( $title instanceof LinkTarget ) {
            return $this->formatTitle(
                $title->getNamespace(),
                $title->getText(),
                $title->getFragment(),
                $title->getInterwiki()
            );
        } elseif ( $title instanceof PageReference ) {
            $title->assertWiki( PageReference::LOCAL );
            return $this->formatTitle(
                $title->getNamespace(),
                $this->getText( $title )
            );
        } else {
            throw new InvalidArgumentException( '$title has invalid type: ' . get_class( $title ) );
        }
    }

    /**
     * Validates, normalizes and splits a title string.
     * This is the "source of truth" for title validity.
     *
     * This function removes illegal characters, splits off the interwiki and
     * namespace prefixes, sets the other forms, and canonicalizes
     * everything.
     *
     * @todo this method is only exposed as a temporary measure to ease refactoring.
     * It was copied with minimal changes from Title::secureAndSplit().
     *
     * @todo This method should be split up and an appropriate interface
     * defined for use by the Title class.
     *
     * @param string $text
     * @param int $defaultNamespace
     *
     * @internal
     * @throws MalformedTitleException If $text is not a valid title string.
     * @return array A map with the fields 'interwiki', 'fragment', 'namespace', and 'dbkey'.
     */
    public function splitTitleString( $text, $defaultNamespace = NS_MAIN ) {
        $dbkey = str_replace( ' ', '_', $text );

        # Initialisation
        $parts = [
            'interwiki' => '',
            'local_interwiki' => false,
            'fragment' => '',
            'namespace' => (int)$defaultNamespace,
            'dbkey' => $dbkey,
        ];

        # Strip Unicode bidi override characters.
        # Sometimes they slip into cut-n-pasted page titles, where the
        # override chars get included in list displays.
        $dbkey = preg_replace( '/[\x{200E}\x{200F}\x{202A}-\x{202E}]+/u', '', $dbkey );

        if ( $dbkey === null ) {
            # Regex had an error. Most likely this is caused by invalid UTF-8
            $exception = ( $this->createMalformedTitleException )( 'title-invalid-utf8', $text );
            throw $exception;
        }

        # Clean up whitespace
        $dbkey = preg_replace(
            '/[ _\xA0\x{1680}\x{180E}\x{2000}-\x{200A}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}]+/u',
            '_',
            $dbkey
        );
        $dbkey = trim( $dbkey, '_' );

        if ( strpos( $dbkey, \UtfNormal\Constants::UTF8_REPLACEMENT ) !== false ) {
            # Contained illegal UTF-8 sequences or forbidden Unicode chars.
            $exception = ( $this->createMalformedTitleException )( 'title-invalid-utf8', $text );
            throw $exception;
        }

        $parts['dbkey'] = $dbkey;

        # Initial colon indicates main namespace rather than specified default
        # but should not create invalid {ns,title} pairs such as {0,Project:Foo}
        if ( $dbkey !== '' && $dbkey[0] == ':' ) {
            $parts['namespace'] = NS_MAIN;
            $dbkey = substr( $dbkey, 1 ); # remove the colon but continue processing
            $dbkey = trim( $dbkey, '_' ); # remove any subsequent whitespace
        }

        if ( $dbkey == '' ) {
            $exception = ( $this->createMalformedTitleException )( 'title-invalid-empty', $text );
            throw $exception;
        }

        # Namespace or interwiki prefix
        $prefixRegexp = "/^(.+?)_*:_*(.*)$/S";
        do {
            $m = [];
            if ( preg_match( $prefixRegexp, $dbkey, $m ) ) {
                $p = $m[1];
                $ns = $this->language->getNsIndex( $p );
                if ( $ns !== false ) {
                    # Ordinary namespace
                    $dbkey = $m[2];
                    $parts['namespace'] = $ns;
                    # For Talk:X pages, check if X has a "namespace" prefix
                    if ( $ns === NS_TALK && preg_match( $prefixRegexp, $dbkey, $x ) ) {
                        if ( $this->language->getNsIndex( $x[1] ) ) {
                            # Disallow Talk:File:x type titles...
                            $exception = ( $this->createMalformedTitleException )(
                                'title-invalid-talk-namespace',
                                $text
                            );
                            throw $exception;
                        } elseif ( $this->interwikiLookup->isValidInterwiki( $x[1] ) ) {
                            # Disallow Talk:Interwiki:x type titles...
                            $exception = ( $this->createMalformedTitleException )(
                                'title-invalid-talk-namespace',
                                $text
                            );
                            throw $exception;
                        }
                    }
                } elseif ( $this->interwikiLookup->isValidInterwiki( $p ) ) {
                    # Interwiki link
                    $dbkey = $m[2];
                    $parts['interwiki'] = $this->language->lc( $p );

                    # Redundant interwiki prefix to the local wiki
                    foreach ( $this->localInterwikis as $localIW ) {
                        if ( strcasecmp( $parts['interwiki'], $localIW ) == 0 ) {
                            if ( $dbkey == '' ) {
                                # Empty self-links should point to the Main Page, to ensure
                                # compatibility with cross-wiki transclusions and the like.
                                $mainPage = Title::newMainPage();
                                return [
                                    'interwiki' => $mainPage->getInterwiki(),
                                    'local_interwiki' => true,
                                    'fragment' => $mainPage->getFragment(),
                                    'namespace' => $mainPage->getNamespace(),
                                    'dbkey' => $mainPage->getDBkey(),
                                ];
                            }
                            $parts['interwiki'] = '';
                            # local interwikis should behave like initial-colon links
                            $parts['local_interwiki'] = true;

                            # Do another namespace split...
                            continue 2;
                        }
                    }

                    # If there's an initial colon after the interwiki, that also
                    # resets the default namespace
                    if ( $dbkey !== '' && $dbkey[0] == ':' ) {
                        $parts['namespace'] = NS_MAIN;
                        $dbkey = substr( $dbkey, 1 );
                        $dbkey = trim( $dbkey, '_' );
                    }
                }
                # If there's no recognized interwiki or namespace,
                # then let the colon expression be part of the title.
            }
            break;
        } while ( true );

        $fragment = strstr( $dbkey, '#' );
        if ( $fragment !== false ) {
            $parts['fragment'] = str_replace( '_', ' ', substr( $fragment, 1 ) );
            $dbkey = substr( $dbkey, 0, strlen( $dbkey ) - strlen( $fragment ) );
            # remove whitespace again: prevents "Foo_bar_#"
            # becoming "Foo_bar_"
            $dbkey = rtrim( $dbkey, "_" );
        }

        # Reject illegal characters.
        $rxTc = self::getTitleInvalidRegex();
        $matches = [];
        if ( preg_match( $rxTc, $dbkey, $matches ) ) {
            $exception = ( $this->createMalformedTitleException )( 'title-invalid-characters', $text, [ $matches[0] ] );
            throw $exception;
        }

        # Pages with "/./" or "/../" appearing in the URLs will often be un-
        # reachable due to the way web browsers deal with 'relative' URLs.
        # Also, they conflict with subpage syntax.  Forbid them explicitly.
        if (
            str_contains( $dbkey, '.' ) &&
            (
                $dbkey === '.' || $dbkey === '..' ||
                str_starts_with( $dbkey, './' ) ||
                str_starts_with( $dbkey, '../' ) ||
                str_contains( $dbkey, '/./' ) ||
                str_contains( $dbkey, '/../' ) ||
                str_ends_with( $dbkey, '/.' ) ||
                str_ends_with( $dbkey, '/..' )
            )
        ) {
            $exception = ( $this->createMalformedTitleException )( 'title-invalid-relative', $text );
            throw $exception;
        }

        # Magic tilde sequences? Nu-uh!
        if ( strpos( $dbkey, '~~~' ) !== false ) {
            $exception = ( $this->createMalformedTitleException )( 'title-invalid-magic-tilde', $text );
            throw $exception;
        }

        # Limit the size of titles to 255 bytes. This is typically the size of the
        # underlying database field. We make an exception for special pages, which
        # don't need to be stored in the database, and may edge over 255 bytes due
        # to subpage syntax for long titles, e.g. [[Special:Block/Long name]]
        $maxLength = ( $parts['namespace'] !== NS_SPECIAL ) ? 255 : 512;
        if ( strlen( $dbkey ) > $maxLength ) {
            $exception = ( $this->createMalformedTitleException )(
                'title-invalid-too-long',
                $text,
                [ Message::numParam( $maxLength ) ]
            );
            throw $exception;
        }

        # Normally, all wiki links are forced to have an initial capital letter so [[foo]]
        # and [[Foo]] point to the same place.  Don't force it for interwikis, since the
        # other site might be case-sensitive.
        if ( $parts['interwiki'] === '' && $this->nsInfo->isCapitalized( $parts['namespace'] ) ) {
            $dbkey = $this->language->ucfirst( $dbkey );
        }

        # Can't make a link to a namespace alone... "empty" local links can only be
        # self-links with a fragment identifier.
        if ( $dbkey == '' && $parts['interwiki'] === '' && $parts['namespace'] !== NS_MAIN ) {
            $exception = ( $this->createMalformedTitleException )( 'title-invalid-empty', $text );
            throw $exception;
        }

        // Allow IPv6 usernames to start with '::' by canonicalizing IPv6 titles.
        // IP names are not allowed for accounts, and can only be referring to
        // edits from the IP. Given '::' abbreviations and caps/lowercaps,
        // there are numerous ways to present the same IP. Having sp:contribs scan
        // them all is silly and having some show the edits and others not is
        // inconsistent. Same for talk/userpages. Keep them normalized instead.
        if ( $dbkey !== '' && ( $parts['namespace'] === NS_USER || $parts['namespace'] === NS_USER_TALK ) ) {
            $dbkey = IPUtils::sanitizeIP( $dbkey );
            // IPUtils::sanitizeIP return null only for bad input
            '@phan-var string $dbkey';
        }

        // Any remaining initial :s are illegal.
        if ( $dbkey !== '' && $dbkey[0] == ':' ) {
            $exception = ( $this->createMalformedTitleException )( 'title-invalid-leading-colon', $text );
            throw $exception;
        }

        // Fill fields
        $parts['dbkey'] = $dbkey;

        // Check to ensure that the return value can be used to construct a TitleValue.
        // All issues should in theory be caught above, this is here to enforce consistency.
        try {
            TitleValue::assertValidSpec(
                $parts['namespace'],
                $parts['dbkey'],
                $parts['fragment'],
                $parts['interwiki']
            );
        } catch ( InvalidArgumentException $ex ) {
            $exception = ( $this->createMalformedTitleException )( 'title-invalid', $text, [ $ex->getMessage() ] );
            throw $exception;
        }

        return $parts;
    }

    /**
     * Returns a simple regex that will match on characters and sequences invalid in titles.
     * Note that this doesn't pick up many things that could be wrong with titles, but that
     * replacing this regex with something valid will make many titles valid.
     * Previously Title::getTitleInvalidRegex()
     *
     * @return string Regex string
     * @since 1.25
     */
    public static function getTitleInvalidRegex() {
        static $rxTc = false;
        if ( !$rxTc ) {
            # Matching titles will be held as illegal.
            $rxTc = '/' .
                # Any character not allowed is forbidden...
                '[^' . Title::legalChars() . ']' .
                # URL percent encoding sequences interfere with the ability
                # to round-trip titles -- you can't link to them consistently.
                '|%[0-9A-Fa-f]{2}' .
                # XML/HTML character references produce similar issues.
                '|&[A-Za-z0-9\x80-\xff]+;' .
                '/S';
        }

        return $rxTc;
    }
}

/** @deprecated class alias since 1.41 */
class_alias( MediaWikiTitleCodec::class, 'MediaWikiTitleCodec' );