wikimedia/mediawiki-core

View on GitHub
includes/filerepo/FileRepo.php

Summary

Maintainability
F
1 wk
Test Coverage
<?php
/**
 * @defgroup FileRepo File Repository
 *
 * @brief This module handles how MediaWiki interacts with filesystems.
 *
 * @details
 */

use MediaWiki\Context\RequestContext;
use MediaWiki\Linker\LinkTarget;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use MediaWiki\Page\PageIdentity;
use MediaWiki\Permissions\Authority;
use MediaWiki\Status\Status;
use MediaWiki\Title\Title;
use MediaWiki\User\UserIdentity;
use MediaWiki\Utils\MWTimestamp;
use Wikimedia\AtEase\AtEase;

/**
 * Base code for file repositories.
 *
 * 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 FileRepo
 */

/**
 * Base class for file repositories
 *
 * See [the architecture doc](@ref filerepoarch) for more information.
 *
 * @ingroup FileRepo
 */
class FileRepo {
    public const DELETE_SOURCE = 1;
    public const OVERWRITE = 2;
    public const OVERWRITE_SAME = 4;
    public const SKIP_LOCKING = 8;

    public const NAME_AND_TIME_ONLY = 1;

    /** @var bool Whether to fetch commons image description pages and display
     *    them on the local wiki
     */
    public $fetchDescription;

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

    /** @var bool */
    protected $hasSha1Storage = false;

    /** @var bool */
    protected $supportsSha1URLs = false;

    /** @var FileBackend */
    protected $backend;

    /** @var array Map of zones to config */
    protected $zones = [];

    /** @var string URL of thumb.php */
    protected $thumbScriptUrl;

    /** @var bool Whether to skip media file transformation on parse and rely
     *    on a 404 handler instead.
     */
    protected $transformVia404;

    /** @var string URL of image description pages, e.g.
     *    https://en.wikipedia.org/wiki/File:
     */
    protected $descBaseUrl;

    /** @var string URL of the MediaWiki installation, equivalent to
     *    $wgScriptPath, e.g. https://en.wikipedia.org/w
     */
    protected $scriptDirUrl;

    /** @var string Equivalent to $wgArticlePath, e.g. https://en.wikipedia.org/wiki/$1 */
    protected $articleUrl;

    /** @var bool Equivalent to $wgCapitalLinks (or $wgCapitalLinkOverrides[NS_FILE],
     *    determines whether filenames implicitly start with a capital letter.
     *    The current implementation may give incorrect description page links
     *    when the local $wgCapitalLinks and initialCapital are mismatched.
     */
    protected $initialCapital;

    /** @var string May be 'paranoid' to remove all parameters from error
     *    messages, 'none' to leave the paths in unchanged, or 'simple' to
     *    replace paths with placeholders. Default for LocalRepo is
     *    'simple'.
     */
    protected $pathDisclosureProtection = 'simple';

    /** @var string|false Public zone URL. */
    protected $url;

    /** @var string|false The base thumbnail URL. Defaults to "<url>/thumb". */
    protected $thumbUrl;

    /** @var int The number of directory levels for hash-based division of files */
    protected $hashLevels;

    /** @var int The number of directory levels for hash-based division of deleted files */
    protected $deletedHashLevels;

    /** @var int File names over this size will use the short form of thumbnail
     *    names. Short thumbnail names only have the width, parameters, and the
     *    extension.
     */
    protected $abbrvThreshold;

    /** @var null|string The URL to a favicon (optional, may be a server-local path URL). */
    protected $favicon = null;

    /** @var bool Whether all zones should be private (e.g. private wiki repo) */
    protected $isPrivate;

    /** @var callable Override these in the base class */
    protected $fileFactory = [ UnregisteredLocalFile::class, 'newFromTitle' ];
    /** @var callable|false Override these in the base class */
    protected $oldFileFactory = false;
    /** @var callable|false Override these in the base class */
    protected $fileFactoryKey = false;
    /** @var callable|false Override these in the base class */
    protected $oldFileFactoryKey = false;

    /** @var string URL of where to proxy thumb.php requests to.
     *    Example: http://127.0.0.1:8888/wiki/dev/thumb/
     */
    protected $thumbProxyUrl;
    /** @var string Secret key to pass as an X-Swift-Secret header to the proxied thumb service */
    protected $thumbProxySecret;

    /** @var bool Disable local image scaling */
    protected $disableLocalTransform = false;

    /** @var WANObjectCache */
    protected $wanCache;

    /**
     * @var string
     * @note Use $this->getName(). Public for back-compat only
     * @todo make protected
     */
    public $name;

    /**
     * @see Documentation of info options at $wgLocalFileRepo
     * @param array|null $info
     * @phan-assert array $info
     */
    public function __construct( array $info = null ) {
        // Verify required settings presence
        if (
            $info === null
            || !array_key_exists( 'name', $info )
            || !array_key_exists( 'backend', $info )
        ) {
            throw new InvalidArgumentException( __CLASS__ .
                " requires an array of options having both 'name' and 'backend' keys.\n" );
        }

        // Required settings
        $this->name = $info['name'];
        if ( $info['backend'] instanceof FileBackend ) {
            $this->backend = $info['backend']; // useful for testing
        } else {
            $this->backend =
                MediaWikiServices::getInstance()->getFileBackendGroup()->get( $info['backend'] );
        }

        // Optional settings that can have no value
        $optionalSettings = [
            'descBaseUrl', 'scriptDirUrl', 'articleUrl', 'fetchDescription',
            'thumbScriptUrl', 'pathDisclosureProtection', 'descriptionCacheExpiry',
            'favicon', 'thumbProxyUrl', 'thumbProxySecret', 'disableLocalTransform'
        ];
        foreach ( $optionalSettings as $var ) {
            if ( isset( $info[$var] ) ) {
                $this->$var = $info[$var];
            }
        }

        // Optional settings that have a default
        $localCapitalLinks =
            MediaWikiServices::getInstance()->getNamespaceInfo()->isCapitalized( NS_FILE );
        $this->initialCapital = $info['initialCapital'] ?? $localCapitalLinks;
        if ( $localCapitalLinks && !$this->initialCapital ) {
            // If the local wiki's file namespace requires an initial capital, but a foreign file
            // repo doesn't, complications will result. Linker code will want to auto-capitalize the
            // first letter of links to files, but those links might actually point to files on
            // foreign wikis with initial-lowercase names. This combination is not likely to be
            // used by anyone anyway, so we just outlaw it to save ourselves the bugs. If you want
            // to include a foreign file repo with initialCapital false, set your local file
            // namespace to not be capitalized either.
            throw new InvalidArgumentException(
                'File repos with initial capital false are not allowed on wikis where the File ' .
                'namespace has initial capital true' );
        }

        $this->url = $info['url'] ?? false; // a subclass may set the URL (e.g. ForeignAPIRepo)
        $defaultThumbUrl = $this->url ? $this->url . '/thumb' : false;
        $this->thumbUrl = $info['thumbUrl'] ?? $defaultThumbUrl;
        $this->hashLevels = $info['hashLevels'] ?? 2;
        $this->deletedHashLevels = $info['deletedHashLevels'] ?? $this->hashLevels;
        $this->transformVia404 = !empty( $info['transformVia404'] );
        $this->abbrvThreshold = $info['abbrvThreshold'] ?? 255;
        $this->isPrivate = !empty( $info['isPrivate'] );
        // Give defaults for the basic zones...
        $this->zones = $info['zones'] ?? [];
        foreach ( [ 'public', 'thumb', 'transcoded', 'temp', 'deleted' ] as $zone ) {
            if ( !isset( $this->zones[$zone]['container'] ) ) {
                $this->zones[$zone]['container'] = "{$this->name}-{$zone}";
            }
            if ( !isset( $this->zones[$zone]['directory'] ) ) {
                $this->zones[$zone]['directory'] = '';
            }
            if ( !isset( $this->zones[$zone]['urlsByExt'] ) ) {
                $this->zones[$zone]['urlsByExt'] = [];
            }
        }

        $this->supportsSha1URLs = !empty( $info['supportsSha1URLs'] );

        $this->wanCache = $info['wanCache'] ?? WANObjectCache::newEmpty();
    }

    /**
     * Get the file backend instance. Use this function wisely.
     *
     * @return FileBackend
     */
    public function getBackend() {
        return $this->backend;
    }

    /**
     * Get an explanatory message if this repo is read-only.
     * This checks if an administrator disabled writes to the backend.
     *
     * @return string|false Returns false if the repo is not read-only
     */
    public function getReadOnlyReason() {
        return $this->backend->getReadOnlyReason();
    }

    /**
     * Ensure that a single zone or list of zones is defined for usage
     *
     * @param string[]|string $doZones Only do a particular zones
     */
    protected function initZones( $doZones = [] ): void {
        foreach ( (array)$doZones as $zone ) {
            $root = $this->getZonePath( $zone );
            if ( $root === null ) {
                throw new RuntimeException( "No '$zone' zone defined in the {$this->name} repo." );
            }
        }
    }

    /**
     * Determine if a string is an mwrepo:// URL
     *
     * @param string $url
     * @return bool
     */
    public static function isVirtualUrl( $url ) {
        return str_starts_with( $url, 'mwrepo://' );
    }

    /**
     * Get a URL referring to this repository, with the private mwrepo protocol.
     * The suffix, if supplied, is considered to be unencoded, and will be
     * URL-encoded before being returned.
     *
     * @param string|false $suffix
     * @return string
     */
    public function getVirtualUrl( $suffix = false ) {
        $path = 'mwrepo://' . $this->name;
        if ( $suffix !== false ) {
            $path .= '/' . rawurlencode( $suffix );
        }

        return $path;
    }

    /**
     * Get the URL corresponding to one of the four basic zones
     *
     * @param string $zone One of: public, deleted, temp, thumb
     * @param string|null $ext Optional file extension
     * @return string|false
     */
    public function getZoneUrl( $zone, $ext = null ) {
        if ( in_array( $zone, [ 'public', 'thumb', 'transcoded' ] ) ) {
            // standard public zones
            if ( $ext !== null && isset( $this->zones[$zone]['urlsByExt'][$ext] ) ) {
                // custom URL for extension/zone
                // @phan-suppress-next-line PhanTypeArraySuspiciousNullable
                return $this->zones[$zone]['urlsByExt'][$ext];
            } elseif ( isset( $this->zones[$zone]['url'] ) ) {
                // custom URL for zone
                return $this->zones[$zone]['url'];
            }
        }
        switch ( $zone ) {
            case 'public':
                return $this->url;
            case 'temp':
            case 'deleted':
                return false; // no public URL
            case 'thumb':
                return $this->thumbUrl;
            case 'transcoded':
                return "{$this->url}/transcoded";
            default:
                return false;
        }
    }

    /**
     * @return bool Whether non-ASCII path characters are allowed
     */
    public function backendSupportsUnicodePaths() {
        return (bool)( $this->getBackend()->getFeatures() & FileBackend::ATTR_UNICODE_PATHS );
    }

    /**
     * Get the backend storage path corresponding to a virtual URL. Callers are responsible of
     * verifying that $url is a valid virtual URL.
     * Use this function wisely.
     *
     * @param string $url
     * @return string
     */
    public function resolveVirtualUrl( $url ) {
        if ( !str_starts_with( $url, 'mwrepo://' ) ) {
            throw new InvalidArgumentException( __METHOD__ . ': unknown protocol' );
        }
        $bits = explode( '/', substr( $url, 9 ), 3 );
        if ( count( $bits ) != 3 ) {
            throw new InvalidArgumentException( __METHOD__ . ": invalid mwrepo URL: $url" );
        }
        [ $repo, $zone, $rel ] = $bits;
        if ( $repo !== $this->name ) {
            throw new InvalidArgumentException( __METHOD__ . ": fetching from a foreign repo is not supported" );
        }
        $base = $this->getZonePath( $zone );
        if ( !$base ) {
            throw new InvalidArgumentException( __METHOD__ . ": invalid zone: $zone" );
        }

        return $base . '/' . rawurldecode( $rel );
    }

    /**
     * The storage container and base path of a zone
     *
     * @param string $zone
     * @return array (container, base path) or (null, null)
     */
    protected function getZoneLocation( $zone ) {
        if ( !isset( $this->zones[$zone] ) ) {
            return [ null, null ]; // bogus
        }

        return [ $this->zones[$zone]['container'], $this->zones[$zone]['directory'] ];
    }

    /**
     * Get the storage path corresponding to one of the zones
     *
     * @param string $zone
     * @return string|null Returns null if the zone is not defined
     */
    public function getZonePath( $zone ) {
        [ $container, $base ] = $this->getZoneLocation( $zone );
        if ( $container === null || $base === null ) {
            return null;
        }
        $backendName = $this->backend->getName();
        if ( $base != '' ) { // may not be set
            $base = "/{$base}";
        }

        return "mwstore://$backendName/{$container}{$base}";
    }

    /**
     * Create a new File object from the local repository
     *
     * @param PageIdentity|LinkTarget|string $title
     * @param string|false $time Time at which the image was uploaded. If this
     *   is specified, the returned object will be an instance of the
     *   repository's old file class instead of a current file. Repositories
     *   not supporting version control should return false if this parameter
     *   is set.
     * @return File|null A File, or null if passed an invalid Title
     */
    public function newFile( $title, $time = false ) {
        $title = File::normalizeTitle( $title );
        if ( !$title ) {
            return null;
        }
        if ( $time ) {
            if ( $this->oldFileFactory ) {
                return call_user_func( $this->oldFileFactory, $title, $this, $time );
            } else {
                return null;
            }
        } else {
            return call_user_func( $this->fileFactory, $title, $this );
        }
    }

    /**
     * Find an instance of the named file created at the specified time
     * Returns false if the file does not exist. Repositories not supporting
     * version control should return false if the time is specified.
     *
     * @param PageIdentity|LinkTarget|string $title
     * @param array $options Associative array of options:
     *   time:           requested time for a specific file version, or false for the
     *                   current version. An image object will be returned which was
     *                   created at the specified time (which may be archived or current).
     *   ignoreRedirect: If true, do not follow file redirects
     *   private:        If an Authority object, return restricted (deleted) files if the
     *                   performer is allowed to view them. Otherwise, such files will not
     *                   be found. If set and not an Authority object, throws an exception.
     *                   Authority is only accepted since 1.37, User was required before.
     *   latest:         If true, load from the latest available data into File objects
     * @return File|false False on failure
     * @throws InvalidArgumentException
     */
    public function findFile( $title, $options = [] ) {
        if ( !empty( $options['private'] ) && !( $options['private'] instanceof Authority ) ) {
            throw new InvalidArgumentException(
                __METHOD__ . ' called with the `private` option set to something ' .
                'other than an Authority object'
            );
        }

        $title = File::normalizeTitle( $title );
        if ( !$title ) {
            return false;
        }
        if ( isset( $options['bypassCache'] ) ) {
            $options['latest'] = $options['bypassCache']; // b/c
        }
        $time = $options['time'] ?? false;
        $flags = !empty( $options['latest'] ) ? IDBAccessObject::READ_LATEST : 0;
        # First try the current version of the file to see if it precedes the timestamp
        $img = $this->newFile( $title );
        if ( !$img ) {
            return false;
        }
        $img->load( $flags );
        if ( $img->exists() && ( !$time || $img->getTimestamp() == $time ) ) {
            return $img;
        }
        # Now try an old version of the file
        if ( $time !== false ) {
            $img = $this->newFile( $title, $time );
            if ( $img ) {
                $img->load( $flags );
                if ( $img->exists() ) {
                    if ( !$img->isDeleted( File::DELETED_FILE ) ) {
                        return $img; // always OK
                    } elseif (
                        // If its not empty, its an Authority object
                        !empty( $options['private'] ) &&
                        $img->userCan( File::DELETED_FILE, $options['private'] )
                    ) {
                        return $img;
                    }
                }
            }
        }

        # Now try redirects
        if ( !empty( $options['ignoreRedirect'] ) ) {
            return false;
        }
        $redir = $this->checkRedirect( $title );
        if ( $redir && $title->getNamespace() === NS_FILE ) {
            $img = $this->newFile( $redir );
            if ( !$img ) {
                return false;
            }
            $img->load( $flags );
            if ( $img->exists() ) {
                $img->redirectedFrom( $title->getDBkey() );

                return $img;
            }
        }

        return false;
    }

    /**
     * Find many files at once.
     *
     * @param array $items An array of titles, or an array of findFile() options with
     *    the "title" option giving the title. Example:
     *
     *     $findItem = [ 'title' => $title, 'private' => true ];
     *     $findBatch = [ $findItem ];
     *     $repo->findFiles( $findBatch );
     *
     *    No title should appear in $items twice, as the result use titles as keys
     * @param int $flags Supports:
     *     - FileRepo::NAME_AND_TIME_ONLY : return a (search title => (title,timestamp)) map.
     *       The search title uses the input titles; the other is the final post-redirect title.
     *       All titles are returned as string DB keys and the inner array is associative.
     * @return array Map of (file name => File objects) for matches or (search title => (title,timestamp))
     */
    public function findFiles( array $items, $flags = 0 ) {
        $result = [];
        foreach ( $items as $item ) {
            if ( is_array( $item ) ) {
                $title = $item['title'];
                $options = $item;
                unset( $options['title'] );

                if (
                    !empty( $options['private'] ) &&
                    !( $options['private'] instanceof Authority )
                ) {
                    $options['private'] = RequestContext::getMain()->getAuthority();
                }
            } else {
                $title = $item;
                $options = [];
            }
            $file = $this->findFile( $title, $options );
            if ( $file ) {
                $searchName = File::normalizeTitle( $title )->getDBkey(); // must be valid
                if ( $flags & self::NAME_AND_TIME_ONLY ) {
                    $result[$searchName] = [
                        'title' => $file->getTitle()->getDBkey(),
                        'timestamp' => $file->getTimestamp()
                    ];
                } else {
                    $result[$searchName] = $file;
                }
            }
        }

        return $result;
    }

    /**
     * Find an instance of the file with this key, created at the specified time
     * Returns false if the file does not exist. Repositories not supporting
     * version control should return false if the time is specified.
     *
     * @param string $sha1 Base 36 SHA-1 hash
     * @param array $options Option array, same as findFile().
     * @return File|false False on failure
     * @throws InvalidArgumentException if the `private` option is set and not an Authority object
     */
    public function findFileFromKey( $sha1, $options = [] ) {
        if ( !empty( $options['private'] ) && !( $options['private'] instanceof Authority ) ) {
            throw new InvalidArgumentException(
                __METHOD__ . ' called with the `private` option set to something ' .
                'other than an Authority object'
            );
        }

        $time = $options['time'] ?? false;
        # First try to find a matching current version of a file...
        if ( !$this->fileFactoryKey ) {
            return false; // find-by-sha1 not supported
        }
        $img = call_user_func( $this->fileFactoryKey, $sha1, $this, $time );
        if ( $img && $img->exists() ) {
            return $img;
        }
        # Now try to find a matching old version of a file...
        if ( $time !== false && $this->oldFileFactoryKey ) { // find-by-sha1 supported?
            $img = call_user_func( $this->oldFileFactoryKey, $sha1, $this, $time );
            if ( $img && $img->exists() ) {
                if ( !$img->isDeleted( File::DELETED_FILE ) ) {
                    return $img; // always OK
                } elseif (
                    // If its not empty, its an Authority object
                    !empty( $options['private'] ) &&
                    $img->userCan( File::DELETED_FILE, $options['private'] )
                ) {
                    return $img;
                }
            }
        }

        return false;
    }

    /**
     * Get an array or iterator of file objects for files that have a given
     * SHA-1 content hash.
     *
     * STUB
     * @param string $hash SHA-1 hash
     * @return File[]
     */
    public function findBySha1( $hash ) {
        return [];
    }

    /**
     * Get an array of arrays or iterators of file objects for files that
     * have the given SHA-1 content hashes.
     *
     * @param string[] $hashes An array of hashes
     * @return File[][] An Array of arrays or iterators of file objects and the hash as key
     */
    public function findBySha1s( array $hashes ) {
        $result = [];
        foreach ( $hashes as $hash ) {
            $files = $this->findBySha1( $hash );
            if ( count( $files ) ) {
                $result[$hash] = $files;
            }
        }

        return $result;
    }

    /**
     * Return an array of files where the name starts with $prefix.
     *
     * STUB
     * @param string $prefix The prefix to search for
     * @param int $limit The maximum amount of files to return
     * @return LocalFile[]
     */
    public function findFilesByPrefix( $prefix, $limit ) {
        return [];
    }

    /**
     * Get the URL of thumb.php
     *
     * @return string
     */
    public function getThumbScriptUrl() {
        return $this->thumbScriptUrl;
    }

    /**
     * Get the URL thumb.php requests are being proxied to
     *
     * @return string
     */
    public function getThumbProxyUrl() {
        return $this->thumbProxyUrl;
    }

    /**
     * Get the secret key for the proxied thumb service
     *
     * @return string
     */
    public function getThumbProxySecret() {
        return $this->thumbProxySecret;
    }

    /**
     * Returns true if the repository can transform files via a 404 handler
     *
     * @return bool
     */
    public function canTransformVia404() {
        return $this->transformVia404;
    }

    /**
     * Returns true if the repository can transform files locally.
     *
     * @since 1.36
     * @return bool
     */
    public function canTransformLocally() {
        return !$this->disableLocalTransform;
    }

    /**
     * Get the name of a file from its title
     *
     * @param PageIdentity|LinkTarget $title
     * @return string
     */
    public function getNameFromTitle( $title ) {
        if (
            $this->initialCapital !=
            MediaWikiServices::getInstance()->getNamespaceInfo()->isCapitalized( NS_FILE )
        ) {
            $name = $title->getDBkey();
            if ( $this->initialCapital ) {
                $name = MediaWikiServices::getInstance()->getContentLanguage()->ucfirst( $name );
            }
        } else {
            $name = $title->getDBkey();
        }

        return $name;
    }

    /**
     * Get the public zone root storage directory of the repository
     *
     * @return string
     */
    public function getRootDirectory() {
        return $this->getZonePath( 'public' );
    }

    /**
     * Get a relative path including trailing slash, e.g. f/fa/
     * If the repo is not hashed, returns an empty string
     *
     * @param string $name Name of file
     * @return string
     */
    public function getHashPath( $name ) {
        return self::getHashPathForLevel( $name, $this->hashLevels );
    }

    /**
     * Get a relative path including trailing slash, e.g. f/fa/
     * If the repo is not hashed, returns an empty string
     *
     * @param string $suffix Basename of file from FileRepo::storeTemp()
     * @return string
     */
    public function getTempHashPath( $suffix ) {
        $parts = explode( '!', $suffix, 2 ); // format is <timestamp>!<name> or just <name>
        $name = $parts[1] ?? $suffix; // hash path is not based on timestamp
        return self::getHashPathForLevel( $name, $this->hashLevels );
    }

    /**
     * @param string $name
     * @param int $levels
     * @return string
     */
    protected static function getHashPathForLevel( $name, $levels ) {
        if ( $levels == 0 ) {
            return '';
        } else {
            $hash = md5( $name );
            $path = '';
            for ( $i = 1; $i <= $levels; $i++ ) {
                $path .= substr( $hash, 0, $i ) . '/';
            }

            return $path;
        }
    }

    /**
     * Get the number of hash directory levels
     *
     * @return int
     */
    public function getHashLevels() {
        return $this->hashLevels;
    }

    /**
     * Get the name of this repository, as specified by $info['name]' to the constructor
     *
     * @return string
     */
    public function getName() {
        return $this->name;
    }

    /**
     * Make an url to this repo
     *
     * @param string|array $query Query string to append
     * @param string $entry Entry point; defaults to index
     * @return string|false False on failure
     */
    public function makeUrl( $query = '', $entry = 'index' ) {
        if ( isset( $this->scriptDirUrl ) ) {
            return wfAppendQuery( "{$this->scriptDirUrl}/{$entry}.php", $query );
        }

        return false;
    }

    /**
     * Get the URL of an image description page. May return false if it is
     * unknown or not applicable. In general this should only be called by the
     * File class, since it may return invalid results for certain kinds of
     * repositories. Use File::getDescriptionUrl() in user code.
     *
     * In particular, it uses the article paths as specified to the repository
     * constructor, whereas local repositories use the local Title functions.
     *
     * @param string $name
     * @return string|false
     */
    public function getDescriptionUrl( $name ) {
        $encName = wfUrlencode( $name );
        if ( $this->descBaseUrl !== null ) {
            # "http://example.com/wiki/File:"
            return $this->descBaseUrl . $encName;
        }
        if ( $this->articleUrl !== null ) {
            # "http://example.com/wiki/$1"
            # We use "Image:" as the canonical namespace for
            # compatibility across all MediaWiki versions.
            return str_replace( '$1',
                "Image:$encName", $this->articleUrl );
        }
        if ( $this->scriptDirUrl !== null ) {
            # "http://example.com/w"
            # We use "Image:" as the canonical namespace for
            # compatibility across all MediaWiki versions,
            # and just sort of hope index.php is right. ;)
            return $this->makeUrl( "title=Image:$encName" );
        }

        return false;
    }

    /**
     * Get the URL of the content-only fragment of the description page. For
     * MediaWiki this means action=render. This should only be called by the
     * repository's file class, since it may return invalid results. User code
     * should use File::getDescriptionText().
     *
     * @param string $name Name of image to fetch
     * @param string|null $lang Language to fetch it in, if any.
     * @return string|false
     */
    public function getDescriptionRenderUrl( $name, $lang = null ) {
        $query = 'action=render';
        if ( $lang !== null ) {
            $query .= '&uselang=' . urlencode( $lang );
        }
        if ( isset( $this->scriptDirUrl ) ) {
            return $this->makeUrl(
                'title=' .
                wfUrlencode( 'Image:' . $name ) .
                "&$query" );
        } else {
            $descUrl = $this->getDescriptionUrl( $name );
            if ( $descUrl ) {
                return wfAppendQuery( $descUrl, $query );
            } else {
                return false;
            }
        }
    }

    /**
     * Get the URL of the stylesheet to apply to description pages
     *
     * @return string|false False on failure
     */
    public function getDescriptionStylesheetUrl() {
        if ( isset( $this->scriptDirUrl ) ) {
            // Must match canonical query parameter order for optimum caching
            // See HTMLCacheUpdater::getUrls
            return $this->makeUrl( 'title=MediaWiki:Filepage.css&action=raw&ctype=text/css' );
        }

        return false;
    }

    /**
     * Store a file to a given destination.
     *
     * Using FSFile/TempFSFile can improve performance via caching.
     * Using TempFSFile can further improve performance by signalling that it is safe
     * to touch the source file or write extended attribute metadata to it directly.
     *
     * @param string|FSFile $srcPath Source file system path, storage path, or virtual URL
     * @param string $dstZone Destination zone
     * @param string $dstRel Destination relative path
     * @param int $flags Bitwise combination of the following flags:
     *   self::OVERWRITE         Overwrite an existing destination file instead of failing
     *   self::OVERWRITE_SAME    Overwrite the file if the destination exists and has the
     *                           same contents as the source
     *   self::SKIP_LOCKING      Skip any file locking when doing the store
     * @return Status
     */
    public function store( $srcPath, $dstZone, $dstRel, $flags = 0 ) {
        $this->assertWritableRepo(); // fail out if read-only

        $status = $this->storeBatch( [ [ $srcPath, $dstZone, $dstRel ] ], $flags );
        if ( $status->successCount == 0 ) {
            $status->setOK( false );
        }

        return $status;
    }

    /**
     * Store a batch of files
     *
     * @see FileRepo::store()
     *
     * @param array $triplets (src, dest zone, dest rel) triplets as per store()
     * @param int $flags Bitwise combination of the following flags:
     *   self::OVERWRITE         Overwrite an existing destination file instead of failing
     *   self::OVERWRITE_SAME    Overwrite the file if the destination exists and has the
     *                           same contents as the source
     *   self::SKIP_LOCKING      Skip any file locking when doing the store
     * @return Status
     */
    public function storeBatch( array $triplets, $flags = 0 ) {
        $this->assertWritableRepo(); // fail out if read-only

        if ( $flags & self::DELETE_SOURCE ) {
            throw new InvalidArgumentException( "DELETE_SOURCE not supported in " . __METHOD__ );
        }

        $status = $this->newGood();
        $backend = $this->backend; // convenience

        $operations = [];
        // Validate each triplet and get the store operation...
        foreach ( $triplets as [ $src, $dstZone, $dstRel ] ) {
            $srcPath = ( $src instanceof FSFile ) ? $src->getPath() : $src;
            wfDebug( __METHOD__
                . "( \$src='$srcPath', \$dstZone='$dstZone', \$dstRel='$dstRel' )"
            );
            // Resolve source path
            if ( $src instanceof FSFile ) {
                $op = 'store';
            } else {
                $src = $this->resolveToStoragePathIfVirtual( $src );
                $op = FileBackend::isStoragePath( $src ) ? 'copy' : 'store';
            }
            // Resolve destination path
            $root = $this->getZonePath( $dstZone );
            if ( !$root ) {
                throw new RuntimeException( "Invalid zone: $dstZone" );
            }
            if ( !$this->validateFilename( $dstRel ) ) {
                throw new RuntimeException( 'Validation error in $dstRel' );
            }
            $dstPath = "$root/$dstRel";
            $dstDir = dirname( $dstPath );
            // Create destination directories for this triplet
            if ( !$this->initDirectory( $dstDir )->isOK() ) {
                return $this->newFatal( 'directorycreateerror', $dstDir );
            }

            // Copy the source file to the destination
            $operations[] = [
                'op' => $op,
                'src' => $src, // storage path (copy) or local file path (store)
                'dst' => $dstPath,
                'overwrite' => (bool)( $flags & self::OVERWRITE ),
                'overwriteSame' => (bool)( $flags & self::OVERWRITE_SAME ),
            ];
        }

        // Execute the store operation for each triplet
        $opts = [ 'force' => true ];
        if ( $flags & self::SKIP_LOCKING ) {
            $opts['nonLocking'] = true;
        }

        return $status->merge( $backend->doOperations( $operations, $opts ) );
    }

    /**
     * Deletes a batch of files.
     * Each file can be a (zone, rel) pair, virtual url, storage path.
     * It will try to delete each file, but ignores any errors that may occur.
     *
     * @param string[] $files List of files to delete
     * @param int $flags Bitwise combination of the following flags:
     *   self::SKIP_LOCKING      Skip any file locking when doing the deletions
     * @return Status
     */
    public function cleanupBatch( array $files, $flags = 0 ) {
        $this->assertWritableRepo(); // fail out if read-only

        $status = $this->newGood();

        $operations = [];
        foreach ( $files as $path ) {
            if ( is_array( $path ) ) {
                // This is a pair, extract it
                [ $zone, $rel ] = $path;
                $path = $this->getZonePath( $zone ) . "/$rel";
            } else {
                // Resolve source to a storage path if virtual
                $path = $this->resolveToStoragePathIfVirtual( $path );
            }
            $operations[] = [ 'op' => 'delete', 'src' => $path ];
        }
        // Actually delete files from storage...
        $opts = [ 'force' => true ];
        if ( $flags & self::SKIP_LOCKING ) {
            $opts['nonLocking'] = true;
        }

        return $status->merge( $this->backend->doOperations( $operations, $opts ) );
    }

    /**
     * Import a file from the local file system into the repo.
     * This does no locking and overrides existing files.
     * This function can be used to write to otherwise read-only foreign repos.
     * This is intended for copying generated thumbnails into the repo.
     *
     * Using FSFile/TempFSFile can improve performance via caching.
     * Using TempFSFile can further improve performance by signalling that it is safe
     * to touch the source file or write extended attribute metadata to it directly.
     *
     * @param string|FSFile $src Source file system path, storage path, or virtual URL
     * @param string $dst Virtual URL or storage path
     * @param array|string|null $options An array consisting of a key named headers
     *   listing extra headers. If a string, taken as content-disposition header.
     *   (Support for array of options new in 1.23)
     * @return Status
     */
    final public function quickImport( $src, $dst, $options = null ) {
        return $this->quickImportBatch( [ [ $src, $dst, $options ] ] );
    }

    /**
     * Import a batch of files from the local file system into the repo.
     * This does no locking and overrides existing files.
     * This function can be used to write to otherwise read-only foreign repos.
     * This is intended for copying generated thumbnails into the repo.
     *
     * @see FileRepo::quickImport()
     *
     * All path parameters may be a file system path, storage path, or virtual URL.
     * When "headers" are given they are used as HTTP headers if supported.
     *
     * @param array $triples List of (source path or FSFile, destination path, disposition)
     * @return Status
     */
    public function quickImportBatch( array $triples ) {
        $status = $this->newGood();
        $operations = [];
        foreach ( $triples as $triple ) {
            [ $src, $dst ] = $triple;
            if ( $src instanceof FSFile ) {
                $op = 'store';
            } else {
                $src = $this->resolveToStoragePathIfVirtual( $src );
                $op = FileBackend::isStoragePath( $src ) ? 'copy' : 'store';
            }
            $dst = $this->resolveToStoragePathIfVirtual( $dst );

            if ( !isset( $triple[2] ) ) {
                $headers = [];
            } elseif ( is_string( $triple[2] ) ) {
                // back-compat
                $headers = [ 'Content-Disposition' => $triple[2] ];
            } elseif ( is_array( $triple[2] ) && isset( $triple[2]['headers'] ) ) {
                $headers = $triple[2]['headers'];
            } else {
                $headers = [];
            }

            $operations[] = [
                'op' => $op,
                'src' => $src, // storage path (copy) or local path/FSFile (store)
                'dst' => $dst,
                'headers' => $headers
            ];
            $status->merge( $this->initDirectory( dirname( $dst ) ) );
        }

        return $status->merge( $this->backend->doQuickOperations( $operations ) );
    }

    /**
     * Purge a file from the repo. This does no locking.
     * This function can be used to write to otherwise read-only foreign repos.
     * This is intended for purging thumbnails.
     *
     * @param string $path Virtual URL or storage path
     * @return Status
     */
    final public function quickPurge( $path ) {
        return $this->quickPurgeBatch( [ $path ] );
    }

    /**
     * Deletes a directory if empty.
     * This function can be used to write to otherwise read-only foreign repos.
     *
     * @param string $dir Virtual URL (or storage path) of directory to clean
     * @return Status
     */
    public function quickCleanDir( $dir ) {
        return $this->newGood()->merge(
            $this->backend->clean(
                [ 'dir' => $this->resolveToStoragePathIfVirtual( $dir ) ]
            )
        );
    }

    /**
     * Purge a batch of files from the repo.
     * This function can be used to write to otherwise read-only foreign repos.
     * This does no locking and is intended for purging thumbnails.
     *
     * @param string[] $paths List of virtual URLs or storage paths
     * @return Status
     */
    public function quickPurgeBatch( array $paths ) {
        $status = $this->newGood();
        $operations = [];
        foreach ( $paths as $path ) {
            $operations[] = [
                'op' => 'delete',
                'src' => $this->resolveToStoragePathIfVirtual( $path ),
                'ignoreMissingSource' => true
            ];
        }
        $status->merge( $this->backend->doQuickOperations( $operations ) );

        return $status;
    }

    /**
     * Pick a random name in the temp zone and store a file to it.
     * Returns a Status object with the file Virtual URL in the value,
     * file can later be disposed using FileRepo::freeTemp().
     *
     * @param string $originalName The base name of the file as specified
     *   by the user. The file extension will be maintained.
     * @param string $srcPath The current location of the file.
     * @return Status Object with the URL in the value.
     */
    public function storeTemp( $originalName, $srcPath ) {
        $this->assertWritableRepo(); // fail out if read-only

        $date = MWTimestamp::getInstance()->format( 'YmdHis' );
        $hashPath = $this->getHashPath( $originalName );
        $dstUrlRel = $hashPath . $date . '!' . rawurlencode( $originalName );
        $virtualUrl = $this->getVirtualUrl( 'temp' ) . '/' . $dstUrlRel;

        $result = $this->quickImport( $srcPath, $virtualUrl );
        $result->value = $virtualUrl;

        return $result;
    }

    /**
     * Remove a temporary file or mark it for garbage collection
     *
     * @param string $virtualUrl The virtual URL returned by FileRepo::storeTemp()
     * @return bool True on success, false on failure
     */
    public function freeTemp( $virtualUrl ) {
        $this->assertWritableRepo(); // fail out if read-only

        $temp = $this->getVirtualUrl( 'temp' );
        if ( !str_starts_with( $virtualUrl, $temp ) ) {
            wfDebug( __METHOD__ . ": Invalid temp virtual URL" );

            return false;
        }

        return $this->quickPurge( $virtualUrl )->isOK();
    }

    /**
     * Concatenate a list of temporary files into a target file location.
     *
     * @param string[] $srcPaths Ordered list of source virtual URLs/storage paths
     * @param string $dstPath Target file system path
     * @param int $flags Bitwise combination of the following flags:
     *   self::DELETE_SOURCE     Delete the source files on success
     * @return Status
     */
    public function concatenate( array $srcPaths, $dstPath, $flags = 0 ) {
        $this->assertWritableRepo(); // fail out if read-only

        $status = $this->newGood();

        $sources = [];
        foreach ( $srcPaths as $srcPath ) {
            // Resolve source to a storage path if virtual
            $source = $this->resolveToStoragePathIfVirtual( $srcPath );
            $sources[] = $source; // chunk to merge
        }

        // Concatenate the chunks into one FS file
        $params = [ 'srcs' => $sources, 'dst' => $dstPath ];
        $status->merge( $this->backend->concatenate( $params ) );
        if ( !$status->isOK() ) {
            return $status;
        }

        // Delete the sources if required
        if ( $flags & self::DELETE_SOURCE ) {
            $status->merge( $this->quickPurgeBatch( $srcPaths ) );
        }

        // Make sure status is OK, despite any quickPurgeBatch() fatals
        $status->setResult( true );

        return $status;
    }

    /**
     * Copy or move a file either from a storage path, virtual URL,
     * or file system path, into this repository at the specified destination location.
     *
     * Returns a Status object. On success, the value contains "new" or
     * "archived", to indicate whether the file was new with that name.
     *
     * Using FSFile/TempFSFile can improve performance via caching.
     * Using TempFSFile can further improve performance by signalling that it is safe
     * to touch the source file or write extended attribute metadata to it directly.
     *
     * Options to $options include:
     *   - headers : name/value map of HTTP headers to use in response to GET/HEAD requests
     *
     * @param string|FSFile $src The source file system path, storage path, or URL
     * @param string $dstRel The destination relative path
     * @param string $archiveRel The relative path where the existing file is to
     *   be archived, if there is one. Relative to the public zone root.
     * @param int $flags Bitfield, may be FileRepo::DELETE_SOURCE to indicate
     *   that the source file should be deleted if possible
     * @param array $options Optional additional parameters
     * @return Status
     */
    public function publish(
        $src, $dstRel, $archiveRel, $flags = 0, array $options = []
    ) {
        $this->assertWritableRepo(); // fail out if read-only

        $status = $this->publishBatch(
            [ [ $src, $dstRel, $archiveRel, $options ] ], $flags );
        if ( $status->successCount == 0 ) {
            $status->setOK( false );
        }
        $status->value = $status->value[0] ?? false;

        return $status;
    }

    /**
     * Publish a batch of files
     *
     * @see FileRepo::publish()
     *
     * @param array $ntuples (source, dest, archive) triplets or
     *   (source, dest, archive, options) 4-tuples as per publish().
     * @param int $flags Bitfield, may be FileRepo::DELETE_SOURCE to indicate
     *   that the source files should be deleted if possible
     * @return Status
     */
    public function publishBatch( array $ntuples, $flags = 0 ) {
        $this->assertWritableRepo(); // fail out if read-only

        $backend = $this->backend; // convenience
        // Try creating directories
        $this->initZones( 'public' );

        $status = $this->newGood( [] );

        $operations = [];
        $sourceFSFilesToDelete = []; // cleanup for disk source files
        // Validate each triplet and get the store operation...
        foreach ( $ntuples as $ntuple ) {
            [ $src, $dstRel, $archiveRel ] = $ntuple;
            $srcPath = ( $src instanceof FSFile ) ? $src->getPath() : $src;

            $options = $ntuple[3] ?? [];
            // Resolve source to a storage path if virtual
            $srcPath = $this->resolveToStoragePathIfVirtual( $srcPath );
            if ( !$this->validateFilename( $dstRel ) ) {
                throw new RuntimeException( 'Validation error in $dstRel' );
            }
            if ( !$this->validateFilename( $archiveRel ) ) {
                throw new RuntimeException( 'Validation error in $archiveRel' );
            }

            $publicRoot = $this->getZonePath( 'public' );
            $dstPath = "$publicRoot/$dstRel";
            $archivePath = "$publicRoot/$archiveRel";

            $dstDir = dirname( $dstPath );
            $archiveDir = dirname( $archivePath );
            // Abort immediately on directory creation errors since they're likely to be repetitive
            if ( !$this->initDirectory( $dstDir )->isOK() ) {
                return $this->newFatal( 'directorycreateerror', $dstDir );
            }
            if ( !$this->initDirectory( $archiveDir )->isOK() ) {
                return $this->newFatal( 'directorycreateerror', $archiveDir );
            }

            // Set any desired headers to be use in GET/HEAD responses
            $headers = $options['headers'] ?? [];

            // Archive destination file if it exists.
            // This will check if the archive file also exists and fail if does.
            // This is a check to avoid data loss. On Windows and Linux,
            // copy() will overwrite, so the existence check is vulnerable to
            // race conditions unless a functioning LockManager is used.
            // LocalFile also uses SELECT FOR UPDATE for synchronization.
            $operations[] = [
                'op' => 'copy',
                'src' => $dstPath,
                'dst' => $archivePath,
                'ignoreMissingSource' => true
            ];

            // Copy (or move) the source file to the destination
            if ( FileBackend::isStoragePath( $srcPath ) ) {
                $operations[] = [
                    'op' => ( $flags & self::DELETE_SOURCE ) ? 'move' : 'copy',
                    'src' => $srcPath,
                    'dst' => $dstPath,
                    'overwrite' => true, // replace current
                    'headers' => $headers
                ];
            } else {
                $operations[] = [
                    'op' => 'store',
                    'src' => $src, // storage path (copy) or local path/FSFile (store)
                    'dst' => $dstPath,
                    'overwrite' => true, // replace current
                    'headers' => $headers
                ];
                if ( $flags & self::DELETE_SOURCE ) {
                    $sourceFSFilesToDelete[] = $srcPath;
                }
            }
        }

        // Execute the operations for each triplet
        $status->merge( $backend->doOperations( $operations ) );
        // Find out which files were archived...
        foreach ( $ntuples as $i => $ntuple ) {
            [ , , $archiveRel ] = $ntuple;
            $archivePath = $this->getZonePath( 'public' ) . "/$archiveRel";
            if ( $this->fileExists( $archivePath ) ) {
                $status->value[$i] = 'archived';
            } else {
                $status->value[$i] = 'new';
            }
        }
        // Cleanup for disk source files...
        foreach ( $sourceFSFilesToDelete as $file ) {
            AtEase::suppressWarnings();
            unlink( $file ); // FS cleanup
            AtEase::restoreWarnings();
        }

        return $status;
    }

    /**
     * Creates a directory with the appropriate zone permissions.
     * Callers are responsible for doing read-only and "writable repo" checks.
     *
     * @param string $dir Virtual URL (or storage path) of directory to clean
     * @return Status Good status without value for success, fatal otherwise.
     */
    protected function initDirectory( $dir ) {
        $path = $this->resolveToStoragePathIfVirtual( $dir );
        [ , $container, ] = FileBackend::splitStoragePath( $path );

        $params = [ 'dir' => $path ];
        if ( $this->isPrivate
            || $container === $this->zones['deleted']['container']
            || $container === $this->zones['temp']['container']
        ) {
            # Take all available measures to prevent web accessibility of new deleted
            # directories, in case the user has not configured offline storage
            $params = [ 'noAccess' => true, 'noListing' => true ] + $params;
        }

        return $this->newGood()->merge( $this->backend->prepare( $params ) );
    }

    /**
     * Deletes a directory if empty.
     *
     * @param string $dir Virtual URL (or storage path) of directory to clean
     * @return Status
     */
    public function cleanDir( $dir ) {
        $this->assertWritableRepo(); // fail out if read-only

        return $this->newGood()->merge(
            $this->backend->clean(
                [ 'dir' => $this->resolveToStoragePathIfVirtual( $dir ) ]
            )
        );
    }

    /**
     * Checks existence of a file
     *
     * @param string $file Virtual URL (or storage path) of file to check
     * @return bool|null Whether the file exists, or null in case of I/O errors
     */
    public function fileExists( $file ) {
        $result = $this->fileExistsBatch( [ $file ] );

        return $result[0];
    }

    /**
     * Checks existence of an array of files.
     *
     * @param string[] $files Virtual URLs (or storage paths) of files to check
     * @return array<string|int,bool|null> Map of files and either bool indicating whether the files exist,
     *   or null in case of I/O errors
     */
    public function fileExistsBatch( array $files ) {
        $paths = array_map( [ $this, 'resolveToStoragePathIfVirtual' ], $files );
        $this->backend->preloadFileStat( [ 'srcs' => $paths ] );

        $result = [];
        foreach ( $paths as $key => $path ) {
            $result[$key] = $this->backend->fileExists( [ 'src' => $path ] );
        }

        return $result;
    }

    /**
     * Move a file to the deletion archive.
     * If no valid deletion archive exists, this may either delete the file
     * or throw an exception, depending on the preference of the repository
     *
     * @param mixed $srcRel Relative path for the file to be deleted
     * @param mixed $archiveRel Relative path for the archive location.
     *   Relative to a private archive directory.
     * @return Status
     */
    public function delete( $srcRel, $archiveRel ) {
        $this->assertWritableRepo(); // fail out if read-only

        return $this->deleteBatch( [ [ $srcRel, $archiveRel ] ] );
    }

    /**
     * Move a group of files to the deletion archive.
     *
     * If no valid deletion archive is configured, this may either delete the
     * file or throw an exception, depending on the preference of the repository.
     *
     * The overwrite policy is determined by the repository -- currently LocalRepo
     * assumes a naming scheme in the deleted zone based on content hash, as
     * opposed to the public zone which is assumed to be unique.
     *
     * @param array $sourceDestPairs Array of source/destination pairs. Each element
     *   is a two-element array containing the source file path relative to the
     *   public root in the first element, and the archive file path relative
     *   to the deleted zone root in the second element.
     * @return Status
     */
    public function deleteBatch( array $sourceDestPairs ) {
        $this->assertWritableRepo(); // fail out if read-only

        // Try creating directories
        $this->initZones( [ 'public', 'deleted' ] );

        $status = $this->newGood();

        $backend = $this->backend; // convenience
        $operations = [];
        // Validate filenames and create archive directories
        foreach ( $sourceDestPairs as [ $srcRel, $archiveRel ] ) {
            if ( !$this->validateFilename( $srcRel ) ) {
                throw new RuntimeException( __METHOD__ . ':Validation error in $srcRel' );
            } elseif ( !$this->validateFilename( $archiveRel ) ) {
                throw new RuntimeException( __METHOD__ . ':Validation error in $archiveRel' );
            }

            $publicRoot = $this->getZonePath( 'public' );
            $srcPath = "{$publicRoot}/$srcRel";

            $deletedRoot = $this->getZonePath( 'deleted' );
            $archivePath = "{$deletedRoot}/{$archiveRel}";
            $archiveDir = dirname( $archivePath ); // does not touch FS

            // Create destination directories
            if ( !$this->initDirectory( $archiveDir )->isGood() ) {
                return $this->newFatal( 'directorycreateerror', $archiveDir );
            }

            $operations[] = [
                'op' => 'move',
                'src' => $srcPath,
                'dst' => $archivePath,
                // We may have 2+ identical files being deleted,
                // all of which will map to the same destination file
                'overwriteSame' => true // also see T33792
            ];
        }

        // Move the files by execute the operations for each pair.
        // We're now committed to returning an OK result, which will
        // lead to the files being moved in the DB also.
        $opts = [ 'force' => true ];
        return $status->merge( $backend->doOperations( $operations, $opts ) );
    }

    /**
     * Delete files in the deleted directory if they are not referenced in the filearchive table
     *
     * STUB
     * @param string[] $storageKeys
     */
    public function cleanupDeletedBatch( array $storageKeys ) {
        $this->assertWritableRepo();
    }

    /**
     * Get a relative path for a deletion archive key,
     * e.g. s/z/a/ for sza251lrxrc1jad41h5mgilp8nysje52.jpg
     *
     * @param string $key
     * @return string
     */
    public function getDeletedHashPath( $key ) {
        if ( strlen( $key ) < 31 ) {
            throw new InvalidArgumentException( "Invalid storage key '$key'." );
        }
        $path = '';
        for ( $i = 0; $i < $this->deletedHashLevels; $i++ ) {
            $path .= $key[$i] . '/';
        }

        return $path;
    }

    /**
     * If a path is a virtual URL, resolve it to a storage path.
     * Otherwise, just return the path as it is.
     *
     * @param string $path
     * @return string
     */
    protected function resolveToStoragePathIfVirtual( $path ) {
        if ( self::isVirtualUrl( $path ) ) {
            return $this->resolveVirtualUrl( $path );
        }

        return $path;
    }

    /**
     * Get a local FS copy of a file with a given virtual URL/storage path.
     * Temporary files may be purged when the file object falls out of scope.
     *
     * @param string $virtualUrl
     * @return TempFSFile|null|false Returns false for missing file, null on failure
     */
    public function getLocalCopy( $virtualUrl ) {
        $path = $this->resolveToStoragePathIfVirtual( $virtualUrl );

        return $this->backend->getLocalCopy( [ 'src' => $path ] );
    }

    /**
     * Get a local FS file with a given virtual URL/storage path.
     * The file is either an original or a copy. It should not be changed.
     * Temporary files may be purged when the file object falls out of scope.
     *
     * @param string $virtualUrl
     * @return FSFile|null|false Returns false for missing file, null on failure.
     */
    public function getLocalReference( $virtualUrl ) {
        $path = $this->resolveToStoragePathIfVirtual( $virtualUrl );

        return $this->backend->getLocalReference( [ 'src' => $path ] );
    }

    /**
     * Get properties of a file with a given virtual URL/storage path.
     * Properties should ultimately be obtained via FSFile::getProps().
     *
     * @param string $virtualUrl
     * @return array
     */
    public function getFileProps( $virtualUrl ) {
        $fsFile = $this->getLocalReference( $virtualUrl );
        $mwProps = new MWFileProps( MediaWikiServices::getInstance()->getMimeAnalyzer() );
        if ( $fsFile ) {
            $props = $mwProps->getPropsFromPath( $fsFile->getPath(), true );
        } else {
            $props = $mwProps->newPlaceholderProps();
        }

        return $props;
    }

    /**
     * Get the timestamp of a file with a given virtual URL/storage path
     *
     * @param string $virtualUrl
     * @return string|false False on failure
     */
    public function getFileTimestamp( $virtualUrl ) {
        $path = $this->resolveToStoragePathIfVirtual( $virtualUrl );

        return $this->backend->getFileTimestamp( [ 'src' => $path ] );
    }

    /**
     * Get the size of a file with a given virtual URL/storage path
     *
     * @param string $virtualUrl
     * @return int|false
     */
    public function getFileSize( $virtualUrl ) {
        $path = $this->resolveToStoragePathIfVirtual( $virtualUrl );

        return $this->backend->getFileSize( [ 'src' => $path ] );
    }

    /**
     * Get the sha1 (base 36) of a file with a given virtual URL/storage path
     *
     * @param string $virtualUrl
     * @return string|false
     */
    public function getFileSha1( $virtualUrl ) {
        $path = $this->resolveToStoragePathIfVirtual( $virtualUrl );

        return $this->backend->getFileSha1Base36( [ 'src' => $path ] );
    }

    /**
     * Attempt to stream a file with the given virtual URL/storage path
     *
     * @param string $virtualUrl
     * @param array $headers Additional HTTP headers to send on success
     * @param array $optHeaders HTTP request headers (if-modified-since, range, ...)
     * @return Status
     * @since 1.27
     */
    public function streamFileWithStatus( $virtualUrl, $headers = [], $optHeaders = [] ) {
        $path = $this->resolveToStoragePathIfVirtual( $virtualUrl );
        $params = [ 'src' => $path, 'headers' => $headers, 'options' => $optHeaders ];

        // T172851: HHVM does not flush the output properly, causing OOM
        ob_start( null, 1_048_576 );
        ob_implicit_flush( true );

        $status = $this->newGood()->merge( $this->backend->streamFile( $params ) );

        // T186565: Close the buffer, unless it has already been closed
        // in HTTPFileStreamer::resetOutputBuffers().
        if ( ob_get_status() ) {
            ob_end_flush();
        }

        return $status;
    }

    /**
     * Call a callback function for every public regular file in the repository.
     * This only acts on the current version of files, not any old versions.
     * May use either the database or the filesystem.
     *
     * @param callable $callback
     * @return void
     */
    public function enumFiles( $callback ) {
        $this->enumFilesInStorage( $callback );
    }

    /**
     * Call a callback function for every public file in the repository.
     * May use either the database or the filesystem.
     *
     * @param callable $callback
     * @return void
     */
    protected function enumFilesInStorage( $callback ) {
        $publicRoot = $this->getZonePath( 'public' );
        $numDirs = 1 << ( $this->hashLevels * 4 );
        // Use a priori assumptions about directory structure
        // to reduce the tree height of the scanning process.
        for ( $flatIndex = 0; $flatIndex < $numDirs; $flatIndex++ ) {
            $hexString = sprintf( "%0{$this->hashLevels}x", $flatIndex );
            $path = $publicRoot;
            for ( $hexPos = 0; $hexPos < $this->hashLevels; $hexPos++ ) {
                $path .= '/' . substr( $hexString, 0, $hexPos + 1 );
            }
            $iterator = $this->backend->getFileList( [ 'dir' => $path ] );
            if ( $iterator === null ) {
                throw new RuntimeException( __METHOD__ . ': could not get file listing for ' . $path );
            }
            foreach ( $iterator as $name ) {
                // Each item returned is a public file
                call_user_func( $callback, "{$path}/{$name}" );
            }
        }
    }

    /**
     * Determine if a relative path is valid, i.e. not blank or involving directory traversal
     *
     * @param string $filename
     * @return bool
     */
    public function validateFilename( $filename ) {
        if ( strval( $filename ) == '' ) {
            return false;
        }

        return FileBackend::isPathTraversalFree( $filename );
    }

    /**
     * Get a callback function to use for cleaning error message parameters
     *
     * @return callable
     */
    private function getErrorCleanupFunction() {
        switch ( $this->pathDisclosureProtection ) {
            case 'none':
            case 'simple': // b/c
                $callback = [ $this, 'passThrough' ];
                break;
            default: // 'paranoid'
                $callback = [ $this, 'paranoidClean' ];
        }
        return $callback;
    }

    /**
     * Path disclosure protection function
     *
     * @param string $param
     * @return string
     */
    public function paranoidClean( $param ) {
        return '[hidden]';
    }

    /**
     * Path disclosure protection function
     *
     * @param string $param
     * @return string
     */
    public function passThrough( $param ) {
        return $param;
    }

    /**
     * Create a new fatal error
     *
     * @param string $message
     * @param mixed ...$parameters
     * @return Status
     */
    public function newFatal( $message, ...$parameters ) {
        $status = Status::newFatal( $message, ...$parameters );
        $status->cleanCallback = $this->getErrorCleanupFunction();

        return $status;
    }

    /**
     * Create a new good result
     *
     * @param null|mixed $value
     * @return Status
     */
    public function newGood( $value = null ) {
        $status = Status::newGood( $value );
        $status->cleanCallback = $this->getErrorCleanupFunction();

        return $status;
    }

    /**
     * Checks if there is a redirect named as $title. If there is, return the
     * title object. If not, return false.
     * STUB
     *
     * @param PageIdentity|LinkTarget $title Title of image
     * @return Title|false
     */
    public function checkRedirect( $title ) {
        return false;
    }

    /**
     * Invalidates image redirect cache related to that image
     * Doesn't do anything for repositories that don't support image redirects.
     *
     * STUB
     * @param PageIdentity|LinkTarget $title Title of image
     */
    public function invalidateImageRedirect( $title ) {
    }

    /**
     * Get the human-readable name of the repo
     *
     * @return string
     */
    public function getDisplayName() {
        $sitename = MediaWikiServices::getInstance()->getMainConfig()->get( MainConfigNames::Sitename );

        if ( $this->isLocal() ) {
            return $sitename;
        }

        // 'shared-repo-name-wikimediacommons' is used when $wgUseInstantCommons = true
        return wfMessageFallback( 'shared-repo-name-' . $this->name, 'shared-repo' )->text();
    }

    /**
     * Get the portion of the file that contains the origin file name.
     * If that name is too long, then the name "thumbnail.<ext>" will be given.
     *
     * @param string $name
     * @return string
     */
    public function nameForThumb( $name ) {
        if ( strlen( $name ) > $this->abbrvThreshold ) {
            $ext = FileBackend::extensionFromPath( $name );
            $name = ( $ext == '' ) ? 'thumbnail' : "thumbnail.$ext";
        }

        return $name;
    }

    /**
     * Returns true if this the local file repository.
     *
     * @return bool
     */
    public function isLocal() {
        return $this->getName() == 'local';
    }

    /**
     * Get a global, repository-qualified, WAN cache key
     *
     * This might be called from either the site context of the wiki that owns the repo or
     * the site context of another wiki that simply has access to the repo. This returns
     * false if the repository's cache is not accessible from the current site context.
     *
     * @param string $kClassSuffix Key collection name suffix (added to this repo class)
     * @param mixed ...$components Additional key components
     * @return string|false
     */
    public function getSharedCacheKey( $kClassSuffix, ...$components ) {
        return false;
    }

    /**
     * Get a site-local, repository-qualified, WAN cache key
     *
     * These cache keys are not shared among different site context and thus cannot be
     * directly invalidated when repo objects are modified. These are useful when there
     * is no accessible global cache or the values depend on the current site context.
     *
     * @param string $kClassSuffix Key collection name suffix (added to this repo class)
     * @param mixed ...$components Additional key components
     * @return string
     */
    public function getLocalCacheKey( $kClassSuffix, ...$components ) {
        return $this->wanCache->makeKey(
            'filerepo-' . $kClassSuffix,
            $this->getName(),
            ...$components
        );
    }

    /**
     * Get a temporary private FileRepo associated with this repo.
     *
     * Files will be created in the temp zone of this repo.
     * It will have the same backend as this repo.
     *
     * @return TempFileRepo
     */
    public function getTempRepo() {
        return new TempFileRepo( [
            'name' => "{$this->name}-temp",
            'backend' => $this->backend,
            'zones' => [
                'public' => [
                    // Same place storeTemp() uses in the base repo, though
                    // the path hashing is mismatched, which is annoying.
                    'container' => $this->zones['temp']['container'],
                    'directory' => $this->zones['temp']['directory']
                ],
                'thumb' => [
                    'container' => $this->zones['temp']['container'],
                    'directory' => $this->zones['temp']['directory'] == ''
                        ? 'thumb'
                        : $this->zones['temp']['directory'] . '/thumb'
                ],
                'transcoded' => [
                    'container' => $this->zones['temp']['container'],
                    'directory' => $this->zones['temp']['directory'] == ''
                        ? 'transcoded'
                        : $this->zones['temp']['directory'] . '/transcoded'
                ]
            ],
            'hashLevels' => $this->hashLevels, // performance
            'isPrivate' => true // all in temp zone
        ] );
    }

    /**
     * Get an UploadStash associated with this repo.
     *
     * @param UserIdentity|null $user
     * @return UploadStash
     */
    public function getUploadStash( UserIdentity $user = null ) {
        return new UploadStash( $this, $user );
    }

    /**
     * Throw an exception if this repo is read-only by design.
     * This does not and should not check getReadOnlyReason().
     *
     * @throws LogicException
     */
    protected function assertWritableRepo() {
    }

    /**
     * Return information about the repository.
     *
     * @return array
     * @since 1.22
     */
    public function getInfo() {
        $ret = [
            'name' => $this->getName(),
            'displayname' => $this->getDisplayName(),
            'rootUrl' => $this->getZoneUrl( 'public' ),
            'local' => $this->isLocal(),
        ];

        $optionalSettings = [
            'url',
            'thumbUrl',
            'initialCapital',
            'descBaseUrl',
            'scriptDirUrl',
            'articleUrl',
            'fetchDescription',
            'descriptionCacheExpiry',
        ];
        foreach ( $optionalSettings as $k ) {
            if ( isset( $this->$k ) ) {
                $ret[$k] = $this->$k;
            }
        }
        if ( isset( $this->favicon ) ) {
            // Expand any local path to full URL to improve API usability (T77093).
            $ret['favicon'] = MediaWikiServices::getInstance()->getUrlUtils()
                ->expand( $this->favicon );
        }

        return $ret;
    }

    /**
     * Returns whether or not storage is SHA-1 based
     * @return bool
     */
    public function hasSha1Storage() {
        return $this->hasSha1Storage;
    }

    /**
     * Returns whether or not repo supports having originals SHA-1s in the thumb URLs
     * @return bool
     */
    public function supportsSha1URLs() {
        return $this->supportsSha1URLs;
    }
}