Merge "Skin: Remove deprecated skin methods"

[mediawiki.git] / includes / filerepo / file / File.php

<?php
/**
 * @defgroup FileAbstraction File abstraction
 * @ingroup FileRepo
 *
 * Represents files in a repository.
 */

use MediaWiki\Config\ConfigException;
use MediaWiki\Context\IContextSource;
use MediaWiki\HookContainer\ProtectedHookAccessorTrait;
use MediaWiki\Language\Language;
use MediaWiki\Linker\LinkTarget;
use MediaWiki\Logger\LoggerFactory;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use MediaWiki\Page\PageIdentity;
use MediaWiki\Permissions\Authority;
use MediaWiki\PoolCounter\PoolCounterWorkViaCallback;
use MediaWiki\Status\Status;
use MediaWiki\Title\Title;
use MediaWiki\User\UserIdentity;
use Wikimedia\FileBackend\FileBackend;
use Wikimedia\ObjectCache\WANObjectCache;

/**
 * Base code for files.
 *
 * 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 FileAbstraction
 */

/**
 * Implements some public methods and some protected utility functions which
 * are required by multiple child classes. Contains stub functionality for
 * unimplemented public methods.
 *
 * Stub functions which should be overridden are marked with STUB. Some more
 * concrete functions are also typically overridden by child classes.
 *
 * Note that only the repo object knows what its file class is called. You should
 * never name a file class explicitly outside of the repo class. Instead use the
 * repo's factory functions to generate file objects, for example:
 *
 * RepoGroup::singleton()->getLocalRepo()->newFile( $title );
 *
 * Consider the services container below;
 *
 * $services = MediaWikiServices::getInstance();
 *
 * The convenience services $services->getRepoGroup()->getLocalRepo()->newFile()
 * and $services->getRepoGroup()->findFile() should be sufficient in most cases.
 *
 * @TODO: DI - Instead of using MediaWikiServices::getInstance(), a service should
 * ideally accept a RepoGroup in its constructor and then, use $this->repoGroup->findFile()
 * and $this->repoGroup->getLocalRepo()->newFile().
 *
 * @stable to extend
 * @ingroup FileAbstraction
 */
abstract class File implements MediaHandlerState {
        use ProtectedHookAccessorTrait;

        // Bitfield values akin to the revision deletion constants
        public const DELETED_FILE = 1;
        public const DELETED_COMMENT = 2;
        public const DELETED_USER = 4;
        public const DELETED_RESTRICTED = 8;

        /** Force rendering in the current process */
        public const RENDER_NOW = 1;
        /**
         * Force rendering even if thumbnail already exist and using RENDER_NOW
         * I.e. you have to pass both flags: File::RENDER_NOW | File::RENDER_FORCE
         */
        public const RENDER_FORCE = 2;

        public const DELETE_SOURCE = 1;

        // Audience options for File::getDescription()
        public const FOR_PUBLIC = 1;
        public const FOR_THIS_USER = 2;
        public const RAW = 3;

        // Options for File::thumbName()
        public const THUMB_FULL_NAME = 1;

        /**
         * Some member variables can be lazy-initialised using __get(). The
         * initialisation function for these variables is always a function named
         * like getVar(), where Var is the variable name with upper-case first
         * letter.
         *
         * The following variables are initialised in this way in this base class:
         *    name, extension, handler, path, canRender, isSafeFile,
         *    transformScript, hashPath, pageCount, url
         *
         * Code within this class should generally use the accessor function
         * directly, since __get() isn't re-entrant and therefore causes bugs that
         * depend on initialisation order.
         */

        /**
         * The following member variables are not lazy-initialised
         */

        /** @var FileRepo|LocalRepo|ForeignAPIRepo|false */
        public $repo;

        /** @var Title|string|false */
        protected $title;

        /** @var string Text of last error */
        protected $lastError;

        /** @var ?string The name that was used to access the file, before
         *       resolving redirects. Main part of the title, with underscores
         *       per Title::getDBkey().
         */
        protected $redirected;

        /** @var Title */
        protected $redirectedTitle;

        /** @var FSFile|false False if undefined */
        protected $fsFile;

        /** @var MediaHandler */
        protected $handler;

        /** @var string The URL corresponding to one of the four basic zones */
        protected $url;

        /** @var string File extension */
        protected $extension;

        /** @var string|null The name of a file from its title object */
        protected $name;

        /** @var string The storage path corresponding to one of the zones */
        protected $path;

        /** @var string|null Relative path including trailing slash */
        protected $hashPath;

        /** @var int|false Number of pages of a multipage document, or false for
         *    documents which aren't multipage documents
         */
        protected $pageCount;

        /** @var string|false URL of transformscript (for example thumb.php) */
        protected $transformScript;

        /** @var Title */
        protected $redirectTitle;

        /** @var bool Whether the output of transform() for this file is likely to be valid. */
        protected $canRender;

        /** @var bool Whether this media file is in a format that is unlikely to
         *    contain viruses or malicious content
         */
        protected $isSafeFile;

        /** @var string Required Repository class type */
        protected $repoClass = FileRepo::class;

        /** @var array Cache of tmp filepaths pointing to generated bucket thumbnails, keyed by width */
        protected $tmpBucketedThumbCache = [];

        /** @var array */
        private $handlerState = [];

        /**
         * Call this constructor from child classes.
         *
         * Both $title and $repo are optional, though some functions
         * may return false or throw exceptions if they are not set.
         * Most subclasses will want to call assertRepoDefined() here.
         *
         * @stable to call
         * @param Title|string|false $title
         * @param FileRepo|false $repo
         */
        public function __construct( $title, $repo ) {
                // Some subclasses do not use $title, but set name/title some other way
                if ( $title !== false ) {
                        $title = self::normalizeTitle( $title, 'exception' );
                }
                $this->title = $title;
                $this->repo = $repo;
        }

        /**
         * Given a string or Title object return either a
         * valid Title object with namespace NS_FILE or null
         *
         * @param PageIdentity|LinkTarget|string $title
         * @param string|false $exception Use 'exception' to throw an error on bad titles
         * @return Title|null
         */
        public static function normalizeTitle( $title, $exception = false ) {
                $ret = $title;

                if ( !$ret instanceof Title ) {
                        if ( $ret instanceof PageIdentity ) {
                                $ret = Title::castFromPageIdentity( $ret );
                        } elseif ( $ret instanceof LinkTarget ) {
                                $ret = Title::castFromLinkTarget( $ret );
                        }
                }

                if ( $ret instanceof Title ) {
                        # Normalize NS_MEDIA -> NS_FILE
                        if ( $ret->getNamespace() === NS_MEDIA ) {
                                $ret = Title::makeTitleSafe( NS_FILE, $ret->getDBkey() );
                        # Double check the titles namespace
                        } elseif ( $ret->getNamespace() !== NS_FILE ) {
                                $ret = null;
                        }
                } else {
                        # Convert strings to Title objects
                        $ret = Title::makeTitleSafe( NS_FILE, (string)$ret );
                }
                if ( !$ret && $exception !== false ) {
                        throw new RuntimeException( "`$title` is not a valid file title." );
                }

                return $ret;
        }

        public function __get( $name ) {
                $function = [ $this, 'get' . ucfirst( $name ) ];
                if ( !is_callable( $function ) ) {
                        return null;
                } else {
                        $this->$name = $function();

                        return $this->$name;
                }
        }

        /**
         * Normalize a file extension to the common form, making it lowercase and checking some synonyms,
         * and ensure it's clean. Extensions with non-alphanumeric characters will be discarded.
         * Keep in sync with mw.Title.normalizeExtension() in JS.
         *
         * @param string $extension File extension (without the leading dot)
         * @return string File extension in canonical form
         */
        public static function normalizeExtension( $extension ) {
                $lower = strtolower( $extension );
                $squish = [
                        'htm' => 'html',
                        'jpeg' => 'jpg',
                        'mpeg' => 'mpg',
                        'tiff' => 'tif',
                        'ogv' => 'ogg' ];
                if ( isset( $squish[$lower] ) ) {
                        return $squish[$lower];
                } elseif ( preg_match( '/^[0-9a-z]+$/', $lower ) ) {
                        return $lower;
                } else {
                        return '';
                }
        }

        /**
         * Checks if file extensions are compatible
         *
         * @param File $old Old file
         * @param string $new New name
         *
         * @return bool|null
         */
        public static function checkExtensionCompatibility( File $old, $new ) {
                $oldMime = $old->getMimeType();
                $n = strrpos( $new, '.' );
                $newExt = self::normalizeExtension( $n ? substr( $new, $n + 1 ) : '' );
                $mimeMagic = MediaWikiServices::getInstance()->getMimeAnalyzer();

                return $mimeMagic->isMatchingExtension( $newExt, $oldMime );
        }

        /**
         * Upgrade the database row if there is one
         * Called by ImagePage
         * STUB
         *
         * @stable to override
         */
        public function upgradeRow() {
        }

        /**
         * Split an internet media type into its two components; if not
         * a two-part name, set the minor type to 'unknown'.
         *
         * @param ?string $mime "text/html" etc
         * @return string[] ("text", "html") etc
         */
        public static function splitMime( ?string $mime ) {
                if ( $mime === null ) {
                        return [ 'unknown', 'unknown' ];
                } elseif ( str_contains( $mime, '/' ) ) {
                        return explode( '/', $mime, 2 );
                } else {
                        return [ $mime, 'unknown' ];
                }
        }

        /**
         * Callback for usort() to do file sorts by name
         *
         * @param File $a
         * @param File $b
         * @return int Result of name comparison
         */
        public static function compare( File $a, File $b ) {
                return strcmp( $a->getName(), $b->getName() );
        }

        /**
         * Return the name of this file
         *
         * @stable to override
         * @return string
         */
        public function getName() {
                if ( $this->name === null ) {
                        $this->assertRepoDefined();
                        $this->name = $this->repo->getNameFromTitle( $this->title );
                }

                return $this->name;
        }

        /**
         * Get the file extension, e.g. "svg"
         *
         * @stable to override
         * @return string
         */
        public function getExtension() {
                if ( !isset( $this->extension ) ) {
                        $n = strrpos( $this->getName(), '.' );
                        $this->extension = self::normalizeExtension(
                                $n ? substr( $this->getName(), $n + 1 ) : '' );
                }

                return $this->extension;
        }

        /**
         * Return the associated title object
         *
         * @return Title
         */
        public function getTitle() {
                return $this->title;
        }

        /**
         * Return the title used to find this file
         *
         * @return Title
         */
        public function getOriginalTitle() {
                if ( $this->redirected !== null ) {
                        return $this->getRedirectedTitle();
                }

                return $this->title;
        }

        /**
         * Return the URL of the file
         * @stable to override
         *
         * @return string
         */
        public function getUrl() {
                if ( !isset( $this->url ) ) {
                        $this->assertRepoDefined();
                        $ext = $this->getExtension();
                        $this->url = $this->repo->getZoneUrl( 'public', $ext ) . '/' . $this->getUrlRel();
                }

                return $this->url;
        }

        /**
         * Get short description URL for a files based on the page ID
         * @stable to override
         *
         * @return string|null
         * @since 1.27
         */
        public function getDescriptionShortUrl() {
                return null;
        }

        /**
         * Return a fully-qualified URL to the file.
         * Upload URL paths _may or may not_ be fully qualified, so
         * we check. Local paths are assumed to belong on $wgServer.
         * @stable to override
         *
         * @return string
         */
        public function getFullUrl() {
                return (string)MediaWikiServices::getInstance()->getUrlUtils()
                        ->expand( $this->getUrl(), PROTO_RELATIVE );
        }

        /**
         * @stable to override
         * @return string
         */
        public function getCanonicalUrl() {
                return (string)MediaWikiServices::getInstance()->getUrlUtils()
                        ->expand( $this->getUrl(), PROTO_CANONICAL );
        }

        /**
         * @return string
         */
        public function getViewURL() {
                if ( $this->mustRender() ) {
                        if ( $this->canRender() ) {
                                return $this->createThumb( $this->getWidth() );
                        } else {
                                wfDebug( __METHOD__ . ': supposed to render ' . $this->getName() .
                                        ' (' . $this->getMimeType() . "), but can't!" );

                                return $this->getUrl(); # hm... return NULL?
                        }
                } else {
                        return $this->getUrl();
                }
        }

        /**
         * Return the storage path to the file. Note that this does
         * not mean that a file actually exists under that location.
         *
         * This path depends on whether directory hashing is active or not,
         * i.e. whether the files are all found in the same directory,
         * or in hashed paths like /images/3/3c.
         *
         * Most callers don't check the return value, but ForeignAPIFile::getPath
         * returns false.
         *
         * @stable to override
         * @return string|false ForeignAPIFile::getPath can return false
         */
        public function getPath() {
                if ( !isset( $this->path ) ) {
                        $this->assertRepoDefined();
                        $this->path = $this->repo->getZonePath( 'public' ) . '/' . $this->getRel();
                }

                return $this->path;
        }

        /**
         * Get an FS copy or original of this file and return the path.
         * Returns false on failure. Callers must not alter the file.
         * Temporary files are cleared automatically.
         *
         * @return string|false False on failure
         */
        public function getLocalRefPath() {
                $this->assertRepoDefined();
                if ( !isset( $this->fsFile ) ) {
                        $timer = MediaWikiServices::getInstance()->getStatsFactory()
                                ->getTiming( 'media_thumbnail_generate_fetchoriginal_seconds' )
                                ->copyToStatsdAt( 'media.thumbnail.generate.fetchoriginal' );
                        $timer->start();

                        $this->fsFile = $this->repo->getLocalReference( $this->getPath() );

                        $timer->stop();

                        if ( !$this->fsFile ) {
                                $this->fsFile = false; // null => false; cache negative hits
                        }
                }

                return ( $this->fsFile )
                        ? $this->fsFile->getPath()
                        : false;
        }

        /**
         * Return the width of the image. Returns false if the width is unknown
         * or undefined.
         *
         * STUB
         * Overridden by LocalFile, UnregisteredLocalFile
         *
         * @stable to override
         * @param int $page
         * @return int|false
         */
        public function getWidth( $page = 1 ) {
                return false;
        }

        /**
         * Return the height of the image. Returns false if the height is unknown
         * or undefined
         *
         * STUB
         * Overridden by LocalFile, UnregisteredLocalFile
         *
         * @stable to override
         * @param int $page
         * @return int|false False on failure
         */
        public function getHeight( $page = 1 ) {
                return false;
        }

        /**
         * Return the smallest bucket from $wgThumbnailBuckets which is at least
         * $wgThumbnailMinimumBucketDistance larger than $desiredWidth. The returned bucket, if any,
         * will always be bigger than $desiredWidth.
         *
         * @param int $desiredWidth
         * @param int $page
         * @return int|false
         */
        public function getThumbnailBucket( $desiredWidth, $page = 1 ) {
                $thumbnailBuckets = MediaWikiServices::getInstance()
                        ->getMainConfig()->get( MainConfigNames::ThumbnailBuckets );
                $thumbnailMinimumBucketDistance = MediaWikiServices::getInstance()
                        ->getMainConfig()->get( MainConfigNames::ThumbnailMinimumBucketDistance );
                $imageWidth = $this->getWidth( $page );

                if ( $imageWidth === false ) {
                        return false;
                }

                if ( $desiredWidth > $imageWidth ) {
                        return false;
                }

                if ( !$thumbnailBuckets ) {
                        return false;
                }

                $sortedBuckets = $thumbnailBuckets;

                sort( $sortedBuckets );

                foreach ( $sortedBuckets as $bucket ) {
                        if ( $bucket >= $imageWidth ) {
                                return false;
                        }

                        if ( $bucket - $thumbnailMinimumBucketDistance > $desiredWidth ) {
                                return $bucket;
                        }
                }

                // Image is bigger than any available bucket
                return false;
        }

        /**
         * Get the width and height to display image at.
         *
         * @param int $maxWidth Max width to display at
         * @param int $maxHeight Max height to display at
         * @param int $page
         * @return array Array (width, height)
         * @since 1.35
         */
        public function getDisplayWidthHeight( $maxWidth, $maxHeight, $page = 1 ) {
                if ( !$maxWidth || !$maxHeight ) {
                        // should never happen
                        throw new ConfigException( 'Using a choice from $wgImageLimits that is 0x0' );
                }

                $width = $this->getWidth( $page );
                $height = $this->getHeight( $page );
                if ( !$width || !$height ) {
                        return [ 0, 0 ];
                }

                // Calculate the thumbnail size.
                if ( $width <= $maxWidth && $height <= $maxHeight ) {
                        // Vectorized image, do nothing.
                } elseif ( $width / $height >= $maxWidth / $maxHeight ) {
                        # The limiting factor is the width, not the height.
                        $height = round( $height * $maxWidth / $width );
                        $width = $maxWidth;
                        // Note that $height <= $maxHeight now.
                } else {
                        $newwidth = floor( $width * $maxHeight / $height );
                        $height = round( $height * $newwidth / $width );
                        $width = $newwidth;
                        // Note that $height <= $maxHeight now, but might not be identical
                        // because of rounding.
                }
                return [ $width, $height ];
        }

        /**
         * Get the duration of a media file in seconds
         *
         * @stable to override
         * @return float|int
         */
        public function getLength() {
                $handler = $this->getHandler();
                if ( $handler ) {
                        return $handler->getLength( $this );
                } else {
                        return 0;
                }
        }

        /**
         * Return true if the file is vectorized
         *
         * @return bool
         */
        public function isVectorized() {
                $handler = $this->getHandler();
                if ( $handler ) {
                        return $handler->isVectorized( $this );
                } else {
                        return false;
                }
        }

        /**
         * Gives a (possibly empty) list of IETF languages to render
         * the file in.
         *
         * If the file doesn't have translations, or if the file
         * format does not support that sort of thing, returns
         * an empty array.
         *
         * @return string[]
         * @since 1.23
         */
        public function getAvailableLanguages() {
                $handler = $this->getHandler();
                if ( $handler ) {
                        return $handler->getAvailableLanguages( $this );
                } else {
                        return [];
                }
        }

        /**
         * Get the IETF language code from the available languages for this file that matches the language
         * requested by the user
         *
         * @param string $userPreferredLanguage
         * @return string|null
         */
        public function getMatchedLanguage( $userPreferredLanguage ) {
                $handler = $this->getHandler();
                if ( $handler ) {
                        return $handler->getMatchedLanguage(
                                $userPreferredLanguage,
                                $handler->getAvailableLanguages( $this )
                        );
                }

                return null;
        }

        /**
         * In files that support multiple language, what is the default language
         * to use if none specified.
         *
         * @return string|null IETF Lang code, or null if filetype doesn't support multiple languages.
         * @since 1.23
         */
        public function getDefaultRenderLanguage() {
                $handler = $this->getHandler();
                if ( $handler ) {
                        return $handler->getDefaultRenderLanguage( $this );
                } else {
                        return null;
                }
        }

        /**
         * Will the thumbnail be animated if one would expect it to be.
         *
         * Currently used to add a warning to the image description page
         *
         * @return bool False if the main image is both animated
         *   and the thumbnail is not. In all other cases must return
         *   true. If image is not renderable whatsoever, should
         *   return true.
         */
        public function canAnimateThumbIfAppropriate() {
                $handler = $this->getHandler();
                if ( !$handler ) {
                        // We cannot handle image whatsoever, thus
                        // one would not expect it to be animated
                        // so true.
                        return true;
                }

                return !$this->allowInlineDisplay()
                        // Image is not animated, so one would
                        // not expect thumb to be
                        || !$handler->isAnimatedImage( $this )
                        // Image is animated, but thumbnail isn't.
                        // This is unexpected to the user.
                        || $handler->canAnimateThumbnail( $this );
        }

        /**
         * Get handler-specific metadata
         * Overridden by LocalFile, UnregisteredLocalFile
         * STUB
         * @deprecated since 1.37 use getMetadataArray() or getMetadataItem()
         * @return string|false
         */
        public function getMetadata() {
                return false;
        }

        public function getHandlerState( string $key ) {
                return $this->handlerState[$key] ?? null;
        }

        public function setHandlerState( string $key, $value ) {
                $this->handlerState[$key] = $value;
        }

        /**
         * Get the unserialized handler-specific metadata
         * STUB
         * @since 1.37
         * @return array
         */
        public function getMetadataArray(): array {
                return [];
        }

        /**
         * Get a specific element of the unserialized handler-specific metadata.
         *
         * @since 1.37
         * @param string $itemName
         * @return mixed
         */
        public function getMetadataItem( string $itemName ) {
                $items = $this->getMetadataItems( [ $itemName ] );
                return $items[$itemName] ?? null;
        }

        /**
         * Get multiple elements of the unserialized handler-specific metadata.
         *
         * @since 1.37
         * @param string[] $itemNames
         * @return array
         */
        public function getMetadataItems( array $itemNames ): array {
                return array_intersect_key(
                        $this->getMetadataArray(),
                        array_fill_keys( $itemNames, true ) );
        }

        /**
         * Like getMetadata but returns a handler independent array of common values.
         * @see MediaHandler::getCommonMetaArray()
         * @return array|false Array or false if not supported
         * @since 1.23
         */
        public function getCommonMetaArray() {
                $handler = $this->getHandler();
                return $handler ? $handler->getCommonMetaArray( $this ) : false;
        }

        /**
         * get versioned metadata
         *
         * @param array $metadata Array of unserialized metadata
         * @param int|string $version Version number.
         * @return array Array containing metadata, or what was passed to it on fail
         */
        public function convertMetadataVersion( $metadata, $version ) {
                $handler = $this->getHandler();
                if ( $handler ) {
                        return $handler->convertMetadataVersion( $metadata, $version );
                } else {
                        return $metadata;
                }
        }

        /**
         * Return the bit depth of the file
         * Overridden by LocalFile
         * STUB
         * @stable to override
         * @return int
         */
        public function getBitDepth() {
                return 0;
        }

        /**
         * Return the size of the image file, in bytes
         * Overridden by LocalFile, UnregisteredLocalFile
         * STUB
         * @stable to override
         * @return int|false
         */
        public function getSize() {
                return false;
        }

        /**
         * Returns the MIME type of the file.
         * Overridden by LocalFile, UnregisteredLocalFile
         * STUB
         *
         * @stable to override
         * @return string
         */
        public function getMimeType() {
                return 'unknown/unknown';
        }

        /**
         * Return the type of the media in the file.
         * Use the value returned by this function with the MEDIATYPE_xxx constants.
         * Overridden by LocalFile,
         * STUB
         * @stable to override
         * @return string
         */
        public function getMediaType() {
                return MEDIATYPE_UNKNOWN;
        }

        /**
         * Checks if the output of transform() for this file is likely to be valid.
         *
         * In other words, this will return true if a thumbnail can be provided for this
         * image (e.g. if [[File:...|thumb]] produces a result on a wikitext page).
         *
         * If this is false, various user elements will display a placeholder instead.
         *
         * @return bool
         */
        public function canRender() {
                if ( !isset( $this->canRender ) ) {
                        $this->canRender = $this->getHandler() && $this->handler->canRender( $this ) && $this->exists();
                }

                return $this->canRender;
        }

        /**
         * Accessor for __get()
         * @return bool
         */
        protected function getCanRender() {
                return $this->canRender();
        }

        /**
         * Return true if the file is of a type that can't be directly
         * rendered by typical browsers and needs to be re-rasterized.
         *
         * This returns true for everything but the bitmap types
         * supported by all browsers, i.e. JPEG; GIF and PNG. It will
         * also return true for any non-image formats.
         *
         * @stable to override
         * @return bool
         */
        public function mustRender() {
                return $this->getHandler() && $this->handler->mustRender( $this );
        }

        /**
         * Alias for canRender()
         *
         * @return bool
         */
        public function allowInlineDisplay() {
                return $this->canRender();
        }

        /**
         * Determines if this media file is in a format that is unlikely to
         * contain viruses or malicious content. It uses the global
         * $wgTrustedMediaFormats list to determine if the file is safe.
         *
         * This is used to show a warning on the description page of non-safe files.
         * It may also be used to disallow direct [[media:...]] links to such files.
         *
         * Note that this function will always return true if allowInlineDisplay()
         * or isTrustedFile() is true for this file.
         *
         * @return bool
         */
        public function isSafeFile() {
                if ( !isset( $this->isSafeFile ) ) {
                        $this->isSafeFile = $this->getIsSafeFileUncached();
                }

                return $this->isSafeFile;
        }

        /**
         * Accessor for __get()
         *
         * @return bool
         */
        protected function getIsSafeFile() {
                return $this->isSafeFile();
        }

        /**
         * Uncached accessor
         *
         * @return bool
         */
        protected function getIsSafeFileUncached() {
                $trustedMediaFormats = MediaWikiServices::getInstance()->getMainConfig()
                        ->get( MainConfigNames::TrustedMediaFormats );

                if ( $this->allowInlineDisplay() ) {
                        return true;
                }
                if ( $this->isTrustedFile() ) {
                        return true;
                }

                $type = $this->getMediaType();
                $mime = $this->getMimeType();

                if ( !$type || $type === MEDIATYPE_UNKNOWN ) {
                        return false; # unknown type, not trusted
                }
                if ( in_array( $type, $trustedMediaFormats ) ) {
                        return true;
                }

                if ( $mime === "unknown/unknown" ) {
                        return false; # unknown type, not trusted
                }
                if ( in_array( $mime, $trustedMediaFormats ) ) {
                        return true;
                }

                return false;
        }

        /**
         * Returns true if the file is flagged as trusted. Files flagged that way
         * can be linked to directly, even if that is not allowed for this type of
         * file normally.
         *
         * This is a dummy function right now and always returns false. It could be
         * implemented to extract a flag from the database. The trusted flag could be
         * set on upload, if the user has sufficient privileges, to bypass script-
         * and html-filters. It may even be coupled with cryptographic signatures
         * or such.
         *
         * @return bool
         */
        protected function isTrustedFile() {
                # this could be implemented to check a flag in the database,
                # look for signatures, etc
                return false;
        }

        /**
         * Load any lazy-loaded file object fields from source
         *
         * This is only useful when setting $flags
         *
         * Overridden by LocalFile to actually query the DB
         *
         * @stable to override
         * @param int $flags Bitfield of IDBAccessObject::READ_* constants
         */
        public function load( $flags = 0 ) {
        }

        /**
         * Returns true if file exists in the repository.
         *
         * Overridden by LocalFile to avoid unnecessary stat calls.
         *
         * @stable to override
         * @return bool Whether file exists in the repository.
         */
        public function exists() {
                return $this->getPath() && $this->repo->fileExists( $this->path );
        }

        /**
         * Returns true if file exists in the repository and can be included in a page.
         * It would be unsafe to include private images, making public thumbnails inadvertently
         *
         * @stable to override
         * @return bool Whether file exists in the repository and is includable.
         */
        public function isVisible() {
                return $this->exists();
        }

        /**
         * @return string|false
         */
        private function getTransformScript() {
                if ( !isset( $this->transformScript ) ) {
                        $this->transformScript = false;
                        if ( $this->repo ) {
                                $script = $this->repo->getThumbScriptUrl();
                                if ( $script ) {
                                        $this->transformScript = wfAppendQuery( $script, [ 'f' => $this->getName() ] );
                                }
                        }
                }

                return $this->transformScript;
        }

        /**
         * Get a ThumbnailImage which is the same size as the source
         *
         * @param array $handlerParams
         *
         * @return ThumbnailImage|MediaTransformOutput|false False on failure
         */
        public function getUnscaledThumb( $handlerParams = [] ) {
                $hp =& $handlerParams;
                $page = $hp['page'] ?? false;
                $width = $this->getWidth( $page );
                if ( !$width ) {
                        return $this->iconThumb();
                }
                $hp['width'] = $width;
                // be sure to ignore any height specification as well (T64258)
                unset( $hp['height'] );

                return $this->transform( $hp );
        }

        /**
         * Return the file name of a thumbnail with the specified parameters.
         * Use File::THUMB_FULL_NAME to always get a name like "<params>-<source>".
         * Otherwise, the format may be "<params>-<source>" or "<params>-thumbnail.<ext>".
         * @stable to override
         *
         * @param array $params Handler-specific parameters
         * @param int $flags Bitfield that supports THUMB_* constants
         * @return string|null
         */
        public function thumbName( $params, $flags = 0 ) {
                $name = ( $this->repo && !( $flags & self::THUMB_FULL_NAME ) )
                        ? $this->repo->nameForThumb( $this->getName() )
                        : $this->getName();

                return $this->generateThumbName( $name, $params );
        }

        /**
         * Generate a thumbnail file name from a name and specified parameters
         * @stable to override
         *
         * @param string $name
         * @param array $params Parameters which will be passed to MediaHandler::makeParamString
         * @return string|null
         */
        public function generateThumbName( $name, $params ) {
                if ( !$this->getHandler() ) {
                        return null;
                }
                $extension = $this->getExtension();
                [ $thumbExt, ] = $this->getHandler()->getThumbType(
                        $extension, $this->getMimeType(), $params );
                $thumbName = $this->getHandler()->makeParamString( $params );

                if ( $this->repo->supportsSha1URLs() ) {
                        $thumbName .= '-' . $this->getSha1() . '.' . $thumbExt;
                } else {
                        $thumbName .= '-' . $name;

                        if ( $thumbExt != $extension ) {
                                $thumbName .= ".$thumbExt";
                        }
                }

                return $thumbName;
        }

        /**
         * Create a thumbnail of the image having the specified width/height.
         * The thumbnail will not be created if the width is larger than the
         * image's width. Let the browser do the scaling in this case.
         * The thumbnail is stored on disk and is only computed if the thumbnail
         * file does not exist OR if it is older than the image.
         * Returns the URL.
         *
         * Keeps aspect ratio of original image. If both width and height are
         * specified, the generated image will be no bigger than width x height,
         * and will also have correct aspect ratio.
         *
         * @param int $width Maximum width of the generated thumbnail
         * @param int $height Maximum height of the image (optional)
         *
         * @return string
         */
        public function createThumb( $width, $height = -1 ) {
                $params = [ 'width' => $width ];
                if ( $height != -1 ) {
                        $params['height'] = $height;
                }
                $thumb = $this->transform( $params );
                if ( !$thumb || $thumb->isError() ) {
                        return '';
                }

                return $thumb->getUrl();
        }

        /**
         * Return either a MediaTransformError or placeholder thumbnail (if $wgIgnoreImageErrors)
         *
         * @param string $thumbPath Thumbnail storage path
         * @param string $thumbUrl Thumbnail URL
         * @param array $params
         * @param int $flags
         * @return MediaTransformOutput
         */
        protected function transformErrorOutput( $thumbPath, $thumbUrl, $params, $flags ) {
                $ignoreImageErrors = MediaWikiServices::getInstance()->getMainConfig()
                        ->get( MainConfigNames::IgnoreImageErrors );

                $handler = $this->getHandler();
                if ( $handler && $ignoreImageErrors && !( $flags & self::RENDER_NOW ) ) {
                        return $handler->getTransform( $this, $thumbPath, $thumbUrl, $params );
                } else {
                        return new MediaTransformError( 'thumbnail_error',
                                $params['width'], 0, wfMessage( 'thumbnail-dest-create' ) );
                }
        }

        /**
         * Transform a media file
         * @stable to override
         *
         * @param array $params An associative array of handler-specific parameters.
         *   Typical keys are width, height and page.
         * @param int $flags A bitfield, may contain self::RENDER_NOW to force rendering
         * @return ThumbnailImage|MediaTransformOutput|false False on failure
         */
        public function transform( $params, $flags = 0 ) {
                $thumbnailEpoch = MediaWikiServices::getInstance()->getMainConfig()
                        ->get( MainConfigNames::ThumbnailEpoch );

                do {
                        if ( !$this->canRender() ) {
                                $thumb = $this->iconThumb();
                                break; // not a bitmap or renderable image, don't try
                        }

                        // Get the descriptionUrl to embed it as comment into the thumbnail. T21791.
                        $descriptionUrl = $this->getDescriptionUrl();
                        if ( $descriptionUrl ) {
                                $params['descriptionUrl'] = MediaWikiServices::getInstance()->getUrlUtils()
                                        ->expand( $descriptionUrl, PROTO_CANONICAL );
                        }

                        $handler = $this->getHandler();
                        $script = $this->getTransformScript();
                        if ( $script && !( $flags & self::RENDER_NOW ) ) {
                                // Use a script to transform on client request, if possible
                                $thumb = $handler->getScriptedTransform( $this, $script, $params );
                                if ( $thumb ) {
                                        break;
                                }
                        }

                        $normalisedParams = $params;
                        $handler->normaliseParams( $this, $normalisedParams );

                        $thumbName = $this->thumbName( $normalisedParams );
                        $thumbUrl = $this->getThumbUrl( $thumbName );
                        $thumbPath = $this->getThumbPath( $thumbName ); // final thumb path
                        if ( isset( $normalisedParams['isFilePageThumb'] ) && $normalisedParams['isFilePageThumb'] ) {
                                // Use a versioned URL on file description pages
                                $thumbUrl = $this->getFilePageThumbUrl( $thumbUrl );
                        }

                        if ( $this->repo ) {
                                // Defer rendering if a 404 handler is set up...
                                if ( $this->repo->canTransformVia404() && !( $flags & self::RENDER_NOW ) ) {
                                        // XXX: Pass in the storage path even though we are not rendering anything
                                        // and the path is supposed to be an FS path. This is due to getScalerType()
                                        // getting called on the path and clobbering $thumb->getUrl() if it's false.
                                        $thumb = $handler->getTransform( $this, $thumbPath, $thumbUrl, $params );
                                        break;
                                }
                                // Check if an up-to-date thumbnail already exists...
                                wfDebug( __METHOD__ . ": Doing stat for $thumbPath" );
                                if ( !( $flags & self::RENDER_FORCE ) && $this->repo->fileExists( $thumbPath ) ) {
                                        $timestamp = $this->repo->getFileTimestamp( $thumbPath );
                                        if ( $timestamp !== false && $timestamp >= $thumbnailEpoch ) {
                                                // XXX: Pass in the storage path even though we are not rendering anything
                                                // and the path is supposed to be an FS path. This is due to getScalerType()
                                                // getting called on the path and clobbering $thumb->getUrl() if it's false.
                                                $thumb = $handler->getTransform( $this, $thumbPath, $thumbUrl, $params );
                                                $thumb->setStoragePath( $thumbPath );
                                                break;
                                        }
                                } elseif ( $flags & self::RENDER_FORCE ) {
                                        wfDebug( __METHOD__ . " forcing rendering per flag File::RENDER_FORCE" );
                                }

                                // If the backend is ready-only, don't keep generating thumbnails
                                // only to return transformation errors, just return the error now.
                                if ( $this->repo->getReadOnlyReason() !== false ) {
                                        $thumb = $this->transformErrorOutput( $thumbPath, $thumbUrl, $params, $flags );
                                        break;
                                }

                                // Check to see if local transformation is disabled.
                                if ( !$this->repo->canTransformLocally() ) {
                                        LoggerFactory::getInstance( 'thumbnail' )
                                                ->error( 'Local transform denied by configuration' );
                                        $thumb = new MediaTransformError(
                                                wfMessage(
                                                        'thumbnail_error',
                                                        'MediaWiki is configured to disallow local image scaling'
                                                ),
                                                $params['width'],
                                                0
                                        );
                                        break;
                                }
                        }

                        $tmpFile = $this->makeTransformTmpFile( $thumbPath );

                        if ( !$tmpFile ) {
                                $thumb = $this->transformErrorOutput( $thumbPath, $thumbUrl, $params, $flags );
                        } else {
                                $thumb = $this->generateAndSaveThumb( $tmpFile, $params, $flags );
                        }
                } while ( false );

                return is_object( $thumb ) ? $thumb : false;
        }

        /**
         * Generates a thumbnail according to the given parameters and saves it to storage
         * @param TempFSFile $tmpFile Temporary file where the rendered thumbnail will be saved
         * @param array $transformParams
         * @param int $flags
         * @return MediaTransformOutput|false
         */
        public function generateAndSaveThumb( $tmpFile, $transformParams, $flags ) {
                $ignoreImageErrors = MediaWikiServices::getInstance()->getMainConfig()
                        ->get( MainConfigNames::IgnoreImageErrors );

                if ( !$this->repo->canTransformLocally() ) {
                        LoggerFactory::getInstance( 'thumbnail' )
                                ->error( 'Local transform denied by configuration' );
                        return new MediaTransformError(
                                wfMessage(
                                        'thumbnail_error',
                                        'MediaWiki is configured to disallow local image scaling'
                                ),
                                $transformParams['width'],
                                0
                        );
                }

                $statsFactory = MediaWikiServices::getInstance()->getStatsFactory();

                $handler = $this->getHandler();

                $normalisedParams = $transformParams;
                $handler->normaliseParams( $this, $normalisedParams );

                $thumbName = $this->thumbName( $normalisedParams );
                $thumbUrl = $this->getThumbUrl( $thumbName );
                $thumbPath = $this->getThumbPath( $thumbName ); // final thumb path
                if ( isset( $normalisedParams['isFilePageThumb'] ) && $normalisedParams['isFilePageThumb'] ) {
                        // Use a versioned URL on file description pages
                        $thumbUrl = $this->getFilePageThumbUrl( $thumbUrl );
                }

                $tmpThumbPath = $tmpFile->getPath();

                if ( $handler->supportsBucketing() ) {
                        $this->generateBucketsIfNeeded( $normalisedParams, $flags );
                }

                # T367110
                # Calls to doTransform() can recur back on $this->transform()
                # depending on implementation. One such example is PagedTiffHandler.
                # TimingMetric->start() and stop() cannot be used in this situation
                # so we will track the time manually.
                $starttime = microtime( true );

                // Actually render the thumbnail...
                $thumb = $handler->doTransform( $this, $tmpThumbPath, $thumbUrl, $transformParams );
                $tmpFile->bind( $thumb ); // keep alive with $thumb

                $statsFactory->getTiming( 'media_thumbnail_generate_transform_seconds' )
                        ->copyToStatsdAt( 'media.thumbnail.generate.transform' )
                        ->observe( ( microtime( true ) - $starttime ) * 1000 );

                if ( !$thumb ) { // bad params?
                        $thumb = false;
                } elseif ( $thumb->isError() ) { // transform error
                        /** @var MediaTransformError $thumb */
                        '@phan-var MediaTransformError $thumb';
                        $this->lastError = $thumb->toText();
                        // Ignore errors if requested
                        if ( $ignoreImageErrors && !( $flags & self::RENDER_NOW ) ) {
                                $thumb = $handler->getTransform( $this, $tmpThumbPath, $thumbUrl, $transformParams );
                        }
                } elseif ( $this->repo && $thumb->hasFile() && !$thumb->fileIsSource() ) {
                        // Copy the thumbnail from the file system into storage...

                        $timer = $statsFactory->getTiming( 'media_thumbnail_generate_store_seconds' )
                                ->copyToStatsdAt( 'media.thumbnail.generate.store' );
                        $timer->start();

                        $disposition = $this->getThumbDisposition( $thumbName );
                        $status = $this->repo->quickImport( $tmpThumbPath, $thumbPath, $disposition );
                        if ( $status->isOK() ) {
                                $thumb->setStoragePath( $thumbPath );
                        } else {
                                $thumb = $this->transformErrorOutput( $thumbPath, $thumbUrl, $transformParams, $flags );
                        }

                        $timer->stop();

                        // Give extensions a chance to do something with this thumbnail...
                        $this->getHookRunner()->onFileTransformed( $this, $thumb, $tmpThumbPath, $thumbPath );
                }

                return $thumb;
        }

        /**
         * Generates chained bucketed thumbnails if needed
         * @param array $params
         * @param int $flags
         * @return bool Whether at least one bucket was generated
         */
        protected function generateBucketsIfNeeded( $params, $flags = 0 ) {
                if ( !$this->repo
                        || !isset( $params['physicalWidth'] )
                        || !isset( $params['physicalHeight'] )
                ) {
                        return false;
                }

                $bucket = $this->getThumbnailBucket( $params['physicalWidth'] );

                if ( !$bucket || $bucket == $params['physicalWidth'] ) {
                        return false;
                }

                $bucketPath = $this->getBucketThumbPath( $bucket );

                if ( $this->repo->fileExists( $bucketPath ) ) {
                        return false;
                }

                $timer = MediaWikiServices::getInstance()->getStatsFactory()
                        ->getTiming( 'media_thumbnail_generate_bucket_seconds' )
                        ->copyToStatsdAt( 'media.thumbnail.generate.bucket' );
                $timer->start();

                $params['physicalWidth'] = $bucket;
                $params['width'] = $bucket;

                $params = $this->getHandler()->sanitizeParamsForBucketing( $params );

                $tmpFile = $this->makeTransformTmpFile( $bucketPath );

                if ( !$tmpFile ) {
                        return false;
                }

                $thumb = $this->generateAndSaveThumb( $tmpFile, $params, $flags );

                if ( !$thumb || $thumb->isError() ) {
                        return false;
                }

                $timer->stop();

                $this->tmpBucketedThumbCache[$bucket] = $tmpFile->getPath();
                // For the caching to work, we need to make the tmp file survive as long as
                // this object exists
                $tmpFile->bind( $this );

                return true;
        }

        /**
         * Returns the most appropriate source image for the thumbnail, given a target thumbnail size
         * @param array $params
         * @return array Source path and width/height of the source
         */
        public function getThumbnailSource( $params ) {
                if ( $this->repo
                        && $this->getHandler()->supportsBucketing()
                        && isset( $params['physicalWidth'] )
                ) {
                        $bucket = $this->getThumbnailBucket( $params['physicalWidth'] );
                        if ( $bucket ) {
                                if ( $this->getWidth() != 0 ) {
                                        $bucketHeight = round( $this->getHeight() * ( $bucket / $this->getWidth() ) );
                                } else {
                                        $bucketHeight = 0;
                                }

                                // Try to avoid reading from storage if the file was generated by this script
                                if ( isset( $this->tmpBucketedThumbCache[$bucket] ) ) {
                                        $tmpPath = $this->tmpBucketedThumbCache[$bucket];

                                        if ( file_exists( $tmpPath ) ) {
                                                return [
                                                        'path' => $tmpPath,
                                                        'width' => $bucket,
                                                        'height' => $bucketHeight
                                                ];
                                        }
                                }

                                $bucketPath = $this->getBucketThumbPath( $bucket );

                                if ( $this->repo->fileExists( $bucketPath ) ) {
                                        $fsFile = $this->repo->getLocalReference( $bucketPath );

                                        if ( $fsFile ) {
                                                return [
                                                        'path' => $fsFile->getPath(),
                                                        'width' => $bucket,
                                                        'height' => $bucketHeight
                                                ];
                                        }
                                }
                        }
                }

                // Thumbnailing a very large file could result in network saturation if
                // everyone does it at once.
                if ( $this->getSize() >= 1e7 ) { // 10 MB
                        $work = new PoolCounterWorkViaCallback( 'GetLocalFileCopy', sha1( $this->getName() ),
                                [
                                        'doWork' => function () {
                                                return $this->getLocalRefPath();
                                        }
                                ]
                        );
                        $srcPath = $work->execute();
                } else {
                        $srcPath = $this->getLocalRefPath();
                }

                // Original file
                return [
                        'path' => $srcPath,
                        'width' => $this->getWidth(),
                        'height' => $this->getHeight()
                ];
        }

        /**
         * Returns the repo path of the thumb for a given bucket
         * @param int $bucket
         * @return string
         */
        protected function getBucketThumbPath( $bucket ) {
                $thumbName = $this->getBucketThumbName( $bucket );
                return $this->getThumbPath( $thumbName );
        }

        /**
         * Returns the name of the thumb for a given bucket
         * @param int $bucket
         * @return string
         */
        protected function getBucketThumbName( $bucket ) {
                return $this->thumbName( [ 'physicalWidth' => $bucket ] );
        }

        /**
         * Creates a temp FS file with the same extension and the thumbnail
         * @param string $thumbPath Thumbnail path
         * @return TempFSFile|null
         */
        protected function makeTransformTmpFile( $thumbPath ) {
                $thumbExt = FileBackend::extensionFromPath( $thumbPath );
                return MediaWikiServices::getInstance()->getTempFSFileFactory()
                        ->newTempFSFile( 'transform_', $thumbExt );
        }

        /**
         * @param string $thumbName Thumbnail name
         * @param string $dispositionType Type of disposition (either "attachment" or "inline")
         * @return string Content-Disposition header value
         */
        public function getThumbDisposition( $thumbName, $dispositionType = 'inline' ) {
                $fileName = $this->getName(); // file name to suggest
                $thumbExt = FileBackend::extensionFromPath( $thumbName );
                if ( $thumbExt != '' && $thumbExt !== $this->getExtension() ) {
                        $fileName .= ".$thumbExt";
                }

                return FileBackend::makeContentDisposition( $dispositionType, $fileName );
        }

        /**
         * Get a MediaHandler instance for this file
         *
         * @return MediaHandler|false Registered MediaHandler for file's MIME type
         *   or false if none found
         */
        public function getHandler() {
                if ( !isset( $this->handler ) ) {
                        $this->handler = MediaHandler::getHandler( $this->getMimeType() );
                }

                return $this->handler;
        }

        /**
         * Get a ThumbnailImage representing a file type icon
         *
         * @return ThumbnailImage|null
         */
        public function iconThumb() {
                global $IP;
                $resourceBasePath = MediaWikiServices::getInstance()->getMainConfig()
                        ->get( MainConfigNames::ResourceBasePath );
                $assetsPath = "{$resourceBasePath}/resources/assets/file-type-icons/";
                $assetsDirectory = "$IP/resources/assets/file-type-icons/";

                $try = [ 'fileicon-' . $this->getExtension() . '.png', 'fileicon.png' ];
                foreach ( $try as $icon ) {
                        if ( file_exists( $assetsDirectory . $icon ) ) { // always FS
                                $params = [ 'width' => 120, 'height' => 120 ];

                                return new ThumbnailImage( $this, $assetsPath . $icon, false, $params );
                        }
                }

                return null;
        }

        /**
         * Get last thumbnailing error.
         * Largely obsolete.
         * @return string
         */
        public function getLastError() {
                return $this->lastError;
        }

        /**
         * Get all thumbnail names previously generated for this file
         * STUB
         * Overridden by LocalFile
         * @stable to override
         * @return string[]
         */
        protected function getThumbnails() {
                return [];
        }

        /**
         * Purge shared caches such as thumbnails and DB data caching
         * STUB
         * Overridden by LocalFile
         * @stable to override
         * @param array $options Options, which include:
         *   'forThumbRefresh' : The purging is only to refresh thumbnails
         */
        public function purgeCache( $options = [] ) {
        }

        /**
         * Purge the file description page, but don't go after
         * pages using the file. Use when modifying file history
         * but not the current data.
         */
        public function purgeDescription() {
                $title = $this->getTitle();
                if ( $title ) {
                        $title->invalidateCache();
                        $hcu = MediaWikiServices::getInstance()->getHtmlCacheUpdater();
                        $hcu->purgeTitleUrls( $title, $hcu::PURGE_INTENT_TXROUND_REFLECTED );
                }
        }

        /**
         * Purge metadata and all affected pages when the file is created,
         * deleted, or majorly updated.
         */
        public function purgeEverything() {
                // Delete thumbnails and refresh file metadata cache
                $this->purgeCache();
                $this->purgeDescription();
                // Purge cache of all pages using this file
                $title = $this->getTitle();
                if ( $title ) {
                        $job = HTMLCacheUpdateJob::newForBacklinks(
                                $title,
                                'imagelinks',
                                [ 'causeAction' => 'file-purge' ]
                        );
                        MediaWikiServices::getInstance()->getJobQueueGroup()->lazyPush( $job );
                }
        }

        /**
         * Return a fragment of the history of file.
         *
         * STUB
         * @stable to override
         * @param int|null $limit Limit of rows to return
         * @param string|int|null $start Only revisions older than $start will be returned
         * @param string|int|null $end Only revisions newer than $end will be returned
         * @param bool $inc Include the endpoints of the time range
         *
         * @return File[] Guaranteed to be in descending order
         */
        public function getHistory( $limit = null, $start = null, $end = null, $inc = true ) {
                return [];
        }

        /**
         * Return the history of this file, line by line. Starts with current version,
         * then old versions. Should return an object similar to an image/oldimage
         * database row.
         *
         * STUB
         * @stable to override
         * Overridden in LocalFile
         * @return bool
         */
        public function nextHistoryLine() {
                return false;
        }

        /**
         * Reset the history pointer to the first element of the history.
         * Always call this function after using nextHistoryLine() to free db resources
         * STUB
         * Overridden in LocalFile.
         * @stable to override
         */
        public function resetHistory() {
        }

        /**
         * Get the filename hash component of the directory including trailing slash,
         * e.g. f/fa/
         * If the repository is not hashed, returns an empty string.
         *
         * @return string
         */
        public function getHashPath() {
                if ( $this->hashPath === null ) {
                        $this->assertRepoDefined();
                        $this->hashPath = $this->repo->getHashPath( $this->getName() );
                }

                return $this->hashPath;
        }

        /**
         * Get the path of the file relative to the public zone root.
         * This function is overridden in OldLocalFile to be like getArchiveRel().
         *
         * @stable to override
         * @return string
         */
        public function getRel() {
                return $this->getHashPath() . $this->getName();
        }

        /**
         * Get the path of an archived file relative to the public zone root
         * @stable to override
         *
         * @param string|false $suffix If not false, the name of an archived thumbnail file
         *
         * @return string
         */
        public function getArchiveRel( $suffix = false ) {
                $path = 'archive/' . $this->getHashPath();
                if ( $suffix === false ) {
                        $path = rtrim( $path, '/' );
                } else {
                        $path .= $suffix;
                }

                return $path;
        }

        /**
         * Get the path, relative to the thumbnail zone root, of the
         * thumbnail directory or a particular file if $suffix is specified
         * @stable to override
         *
         * @param string|false $suffix If not false, the name of a thumbnail file
         * @return string
         */
        public function getThumbRel( $suffix = false ) {
                $path = $this->getRel();
                if ( $suffix !== false ) {
                        $path .= '/' . $suffix;
                }

                return $path;
        }

        /**
         * Get urlencoded path of the file relative to the public zone root.
         * This function is overridden in OldLocalFile to be like getArchiveUrl().
         * @stable to override
         *
         * @return string
         */
        public function getUrlRel() {
                return $this->getHashPath() . rawurlencode( $this->getName() );
        }

        /**
         * Get the path, relative to the thumbnail zone root, for an archived file's thumbs directory
         * or a specific thumb if the $suffix is given.
         *
         * @param string $archiveName The timestamped name of an archived image
         * @param string|false $suffix If not false, the name of a thumbnail file
         * @return string
         */
        private function getArchiveThumbRel( $archiveName, $suffix = false ) {
                $path = $this->getArchiveRel( $archiveName );
                if ( $suffix !== false ) {
                        $path .= '/' . $suffix;
                }

                return $path;
        }

        /**
         * Get the path of the archived file.
         *
         * @param string|false $suffix If not false, the name of an archived file.
         * @return string
         */
        public function getArchivePath( $suffix = false ) {
                $this->assertRepoDefined();

                return $this->repo->getZonePath( 'public' ) . '/' . $this->getArchiveRel( $suffix );
        }

        /**
         * Get the path of an archived file's thumbs, or a particular thumb if $suffix is specified
         *
         * @param string $archiveName The timestamped name of an archived image
         * @param string|false $suffix If not false, the name of a thumbnail file
         * @return string
         */
        public function getArchiveThumbPath( $archiveName, $suffix = false ) {
                $this->assertRepoDefined();

                return $this->repo->getZonePath( 'thumb' ) . '/' .
                $this->getArchiveThumbRel( $archiveName, $suffix );
        }

        /**
         * Get the path of the thumbnail directory, or a particular file if $suffix is specified
         * @stable to override
         *
         * @param string|false $suffix If not false, the name of a thumbnail file
         * @return string
         */
        public function getThumbPath( $suffix = false ) {
                $this->assertRepoDefined();

                return $this->repo->getZonePath( 'thumb' ) . '/' . $this->getThumbRel( $suffix );
        }

        /**
         * Get the path of the transcoded directory, or a particular file if $suffix is specified
         *
         * @param string|false $suffix If not false, the name of a media file
         * @return string
         */
        public function getTranscodedPath( $suffix = false ) {
                $this->assertRepoDefined();

                return $this->repo->getZonePath( 'transcoded' ) . '/' . $this->getThumbRel( $suffix );
        }

        /**
         * Get the URL of the archive directory, or a particular file if $suffix is specified
         * @stable to override
         *
         * @param string|false $suffix If not false, the name of an archived file
         * @return string
         */
        public function getArchiveUrl( $suffix = false ) {
                $this->assertRepoDefined();
                $ext = $this->getExtension();
                $path = $this->repo->getZoneUrl( 'public', $ext ) . '/archive/' . $this->getHashPath();
                if ( $suffix === false ) {
                        $path = rtrim( $path, '/' );
                } else {
                        $path .= rawurlencode( $suffix );
                }

                return $path;
        }

        /**
         * Get the URL of the archived file's thumbs, or a particular thumb if $suffix is specified
         * @stable to override
         *
         * @param string $archiveName The timestamped name of an archived image
         * @param string|false $suffix If not false, the name of a thumbnail file
         * @return string
         */
        public function getArchiveThumbUrl( $archiveName, $suffix = false ) {
                $this->assertRepoDefined();
                $ext = $this->getExtension();
                $path = $this->repo->getZoneUrl( 'thumb', $ext ) . '/archive/' .
                        $this->getHashPath() . rawurlencode( $archiveName );
                if ( $suffix !== false ) {
                        $path .= '/' . rawurlencode( $suffix );
                }

                return $path;
        }

        /**
         * Get the URL of the zone directory, or a particular file if $suffix is specified
         *
         * @param string $zone Name of requested zone
         * @param string|false $suffix If not false, the name of a file in zone
         * @return string Path
         */
        private function getZoneUrl( $zone, $suffix = false ) {
                $this->assertRepoDefined();
                $ext = $this->getExtension();
                $path = $this->repo->getZoneUrl( $zone, $ext ) . '/' . $this->getUrlRel();
                if ( $suffix !== false ) {
                        $path .= '/' . rawurlencode( $suffix );
                }

                return $path;
        }

        /**
         * Get the URL of the thumbnail directory, or a particular file if $suffix is specified
         * @stable to override
         *
         * @param string|false $suffix If not false, the name of a thumbnail file
         * @return string Path
         */
        public function getThumbUrl( $suffix = false ) {
                return $this->getZoneUrl( 'thumb', $suffix );
        }

        /**
         * Append a version parameter to the end of a file URL
         * Only to be used on File pages.
         * @internal
         *
         * @param string $url Unversioned URL
         * @return string
         */
        public function getFilePageThumbUrl( $url ) {
                if ( $this->repo->isLocal() ) {
                        return wfAppendQuery( $url, urlencode( $this->getTimestamp() ) );
                } else {
                        return $url;
                }
        }

        /**
         * Get the URL of the transcoded directory, or a particular file if $suffix is specified
         *
         * @param string|false $suffix If not false, the name of a media file
         * @return string Path
         */
        public function getTranscodedUrl( $suffix = false ) {
                return $this->getZoneUrl( 'transcoded', $suffix );
        }

        /**
         * Get the public zone virtual URL for a current version source file
         * @stable to override
         *
         * @param string|false $suffix If not false, the name of a thumbnail file
         * @return string
         */
        public function getVirtualUrl( $suffix = false ) {
                $this->assertRepoDefined();
                $path = $this->repo->getVirtualUrl() . '/public/' . $this->getUrlRel();
                if ( $suffix !== false ) {
                        $path .= '/' . rawurlencode( $suffix );
                }

                return $path;
        }

        /**
         * Get the public zone virtual URL for an archived version source file
         * @stable to override
         *
         * @param string|false $suffix If not false, the name of a thumbnail file
         * @return string
         */
        public function getArchiveVirtualUrl( $suffix = false ) {
                $this->assertRepoDefined();
                $path = $this->repo->getVirtualUrl() . '/public/archive/' . $this->getHashPath();
                if ( $suffix === false ) {
                        $path = rtrim( $path, '/' );
                } else {
                        $path .= rawurlencode( $suffix );
                }

                return $path;
        }

        /**
         * Get the virtual URL for a thumbnail file or directory
         * @stable to override
         *
         * @param string|false $suffix If not false, the name of a thumbnail file
         * @return string
         */
        public function getThumbVirtualUrl( $suffix = false ) {
                $this->assertRepoDefined();
                $path = $this->repo->getVirtualUrl() . '/thumb/' . $this->getUrlRel();
                if ( $suffix !== false ) {
                        $path .= '/' . rawurlencode( $suffix );
                }

                return $path;
        }

        /**
         * @return bool
         */
        protected function isHashed() {
                $this->assertRepoDefined();

                return (bool)$this->repo->getHashLevels();
        }

        /**
         * @return never
         */
        protected function readOnlyError() {
                throw new LogicException( static::class . ': write operations are not supported' );
        }

        /**
         * Move or copy a file to its public location. If a file exists at the
         * destination, move it to an archive. Returns a Status object with
         * the archive name in the "value" member on success.
         *
         * The archive name should be passed through to recordUpload3 for database
         * registration.
         *
         * Options to $options include:
         *   - headers : name/value map of HTTP headers to use in response to GET/HEAD requests
         *
         * @param string|FSFile $src Local filesystem path to the source image
         * @param int $flags A bitwise combination of:
         *   File::DELETE_SOURCE    Delete the source file, i.e. move rather than copy
         * @param array $options Optional additional parameters
         * @return Status On success, the value member contains the
         *   archive name, or an empty string if it was a new file.
         *
         * STUB
         * Overridden by LocalFile
         * @stable to override
         */
        public function publish( $src, $flags = 0, array $options = [] ) {
                $this->readOnlyError();
        }

        /**
         * @param IContextSource|false $context
         * @return array[]|false
         */
        public function formatMetadata( $context = false ) {
                $handler = $this->getHandler();
                return $handler ? $handler->formatMetadata( $this, $context ) : false;
        }

        /**
         * Returns true if the file comes from the local file repository.
         *
         * @return bool
         */
        public function isLocal() {
                return $this->repo && $this->repo->isLocal();
        }

        /**
         * Returns the name of the repository.
         *
         * @return string
         */
        public function getRepoName() {
                return $this->repo ? $this->repo->getName() : 'unknown';
        }

        /**
         * Returns the repository
         * @stable to override
         *
         * @return FileRepo|false
         */
        public function getRepo() {
                return $this->repo;
        }

        /**
         * Returns true if the image is an old version
         * STUB
         *
         * @stable to override
         * @return bool
         */
        public function isOld() {
                return false;
        }

        /**
         * Is this file a "deleted" file in a private archive?
         * STUB
         *
         * @stable to override
         * @param int $field One of DELETED_* bitfield constants
         * @return bool
         */
        public function isDeleted( $field ) {
                return false;
        }

        /**
         * Return the deletion bitfield
         * STUB
         * @stable to override
         * @return int
         */
        public function getVisibility() {
                return 0;
        }

        /**
         * Was this file ever deleted from the wiki?
         *
         * @return bool
         */
        public function wasDeleted() {
                $title = $this->getTitle();

                return $title && $title->hasDeletedEdits();
        }

        /**
         * Move file to the new title
         *
         * Move current, old version and all thumbnails
         * to the new filename. Old file is deleted.
         *
         * Cache purging is done; checks for validity
         * and logging are caller's responsibility
         *
         * @stable to override
         * @param Title $target New file name
         * @return Status
         */
        public function move( $target ) {
                $this->readOnlyError();
        }

        /**
         * Delete all versions of the file.
         *
         * @since 1.35
         *
         * Moves the files into an archive directory (or deletes them)
         * and removes the database rows.
         *
         * Cache purging is done; logging is caller's responsibility.
         *
         * @param string $reason
         * @param UserIdentity $user
         * @param bool $suppress Hide content from sysops?
         * @return Status
         * STUB
         * Overridden by LocalFile
         * @stable to override
         */
        public function deleteFile( $reason, UserIdentity $user, $suppress = false ) {
                $this->readOnlyError();
        }

        /**
         * Restore all or specified deleted revisions to the given file.
         * Permissions and logging are left to the caller.
         *
         * May throw database exceptions on error.
         *
         * @param int[] $versions Set of record ids of deleted items to restore,
         *   or empty to restore all revisions.
         * @param bool $unsuppress Remove restrictions on content upon restoration?
         * @return Status
         * STUB
         * Overridden by LocalFile
         * @stable to override
         */
        public function restore( $versions = [], $unsuppress = false ) {
                $this->readOnlyError();
        }

        /**
         * Returns 'true' if this file is a type which supports multiple pages,
         * e.g. DJVU or PDF. Note that this may be true even if the file in
         * question only has a single page.
         *
         * @stable to override
         * @return bool
         */
        public function isMultipage() {
                return $this->getHandler() && $this->handler->isMultiPage( $this );
        }

        /**
         * Returns the number of pages of a multipage document, or false for
         * documents which aren't multipage documents
         *
         * @stable to override
         * @return int|false
         */
        public function pageCount() {
                if ( !isset( $this->pageCount ) ) {
                        if ( $this->getHandler() && $this->handler->isMultiPage( $this ) ) {
                                $this->pageCount = $this->handler->pageCount( $this );
                        } else {
                                $this->pageCount = false;
                        }
                }

                return $this->pageCount;
        }

        /**
         * Calculate the height of a thumbnail using the source and destination width
         *
         * @param int $srcWidth
         * @param int $srcHeight
         * @param int $dstWidth
         *
         * @return int
         */
        public static function scaleHeight( $srcWidth, $srcHeight, $dstWidth ) {
                // Exact integer multiply followed by division
                if ( $srcWidth == 0 ) {
                        return 0;
                } else {
                        return (int)round( $srcHeight * $dstWidth / $srcWidth );
                }
        }

        /**
         * Get the URL of the image description page. May return false if it is
         * unknown or not applicable.
         *
         * @stable to override
         * @return string|false
         */
        public function getDescriptionUrl() {
                if ( $this->repo ) {
                        return $this->repo->getDescriptionUrl( $this->getName() );
                } else {
                        return false;
                }
        }

        /**
         * Get the HTML text of the description page, if available
         * @stable to override
         *
         * @param Language|null $lang Optional language to fetch description in
         * @return string|false HTML
         * @return-taint escaped
         */
        public function getDescriptionText( ?Language $lang = null ) {
                global $wgLang;

                if ( !$this->repo || !$this->repo->fetchDescription ) {
                        return false;
                }

                $lang ??= $wgLang;

                $renderUrl = $this->repo->getDescriptionRenderUrl( $this->getName(), $lang->getCode() );
                if ( $renderUrl ) {
                        $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
                        $key = $this->repo->getLocalCacheKey(
                                'file-remote-description',
                                $lang->getCode(),
                                md5( $this->getName() )
                        );
                        $fname = __METHOD__;

                        return $cache->getWithSetCallback(
                                $key,
                                $this->repo->descriptionCacheExpiry ?: $cache::TTL_UNCACHEABLE,
                                static function ( $oldValue, &$ttl, array &$setOpts ) use ( $renderUrl, $fname ) {
                                        wfDebug( "Fetching shared description from $renderUrl" );
                                        $res = MediaWikiServices::getInstance()->getHttpRequestFactory()->
                                                get( $renderUrl, [], $fname );
                                        if ( !$res ) {
                                                $ttl = WANObjectCache::TTL_UNCACHEABLE;
                                        }

                                        return $res;
                                }
                        );
                }

                return false;
        }

        /**
         * Get the identity of the file uploader.
         *
         * @note if the file does not exist, this will return null regardless of the permissions.
         *
         * @stable to override
         * @since 1.37
         * @param int $audience One of:
         *   File::FOR_PUBLIC       to be displayed to all users
         *   File::FOR_THIS_USER    to be displayed to the given user
         *   File::RAW              get the description regardless of permissions
         * @param Authority|null $performer to check for, only if FOR_THIS_USER is
         *   passed to the $audience parameter
         * @return UserIdentity|null
         */
        public function getUploader( int $audience = self::FOR_PUBLIC, ?Authority $performer = null ): ?UserIdentity {
                return null;
        }

        /**
         * Get description of file revision
         * STUB
         *
         * @stable to override
         * @param int $audience One of:
         *   File::FOR_PUBLIC       to be displayed to all users
         *   File::FOR_THIS_USER    to be displayed to the given user
         *   File::RAW              get the description regardless of permissions
         * @param Authority|null $performer to check for, only if FOR_THIS_USER is
         *   passed to the $audience parameter
         * @return null|string
         */
        public function getDescription( $audience = self::FOR_PUBLIC, ?Authority $performer = null ) {
                return null;
        }

        /**
         * Get the 14-character timestamp of the file upload
         *
         * @stable to override
         * @return string|false TS_MW timestamp or false on failure
         */
        public function getTimestamp() {
                $this->assertRepoDefined();

                return $this->repo->getFileTimestamp( $this->getPath() );
        }

        /**
         * Returns the timestamp (in TS_MW format) of the last change of the description page.
         * Returns false if the file does not have a description page, or retrieving the timestamp
         * would be expensive.
         * @since 1.25
         * @stable to override
         * @return string|false
         */
        public function getDescriptionTouched() {
                return false;
        }

        /**
         * Get the SHA-1 base 36 hash of the file
         *
         * @stable to override
         * @return string|false
         */
        public function getSha1() {
                $this->assertRepoDefined();

                return $this->repo->getFileSha1( $this->getPath() );
        }

        /**
         * Get the deletion archive key, "<sha1>.<ext>"
         *
         * @return string|false
         */
        public function getStorageKey() {
                $hash = $this->getSha1();
                if ( !$hash ) {
                        return false;
                }
                $ext = $this->getExtension();
                $dotExt = $ext === '' ? '' : ".$ext";

                return $hash . $dotExt;
        }

        /**
         * Determine if the current user is allowed to view a particular
         * field of this file, if it's marked as deleted.
         * STUB
         * @stable to override
         * @param int $field
         * @param Authority $performer user object to check
         * @return bool
         */
        public function userCan( $field, Authority $performer ) {
                return true;
        }

        /**
         * @return string[] HTTP header name/value map to use for HEAD/GET request responses
         * @since 1.30
         */
        public function getContentHeaders() {
                $handler = $this->getHandler();
                if ( $handler ) {
                        return $handler->getContentHeaders( $this->getMetadataArray() );
                }

                return [];
        }

        /**
         * @return string
         */
        public function getLongDesc() {
                $handler = $this->getHandler();
                if ( $handler ) {
                        return $handler->getLongDesc( $this );
                } else {
                        return MediaHandler::getGeneralLongDesc( $this );
                }
        }

        /**
         * @return string
         */
        public function getShortDesc() {
                $handler = $this->getHandler();
                if ( $handler ) {
                        return $handler->getShortDesc( $this );
                } else {
                        return MediaHandler::getGeneralShortDesc( $this );
                }
        }

        /**
         * @return string
         */
        public function getDimensionsString() {
                $handler = $this->getHandler();
                if ( $handler ) {
                        return $handler->getDimensionsString( $this );
                } else {
                        return '';
                }
        }

        /**
         * @return ?string The name that was used to access the file, before
         *         resolving redirects.
         */
        public function getRedirected(): ?string {
                return $this->redirected;
        }

        /**
         * @return Title|null
         */
        protected function getRedirectedTitle() {
                if ( $this->redirected !== null ) {
                        if ( !$this->redirectTitle ) {
                                $this->redirectTitle = Title::makeTitle( NS_FILE, $this->redirected );
                        }

                        return $this->redirectTitle;
                }

                return null;
        }

        /**
         * @param string $from The name that was used to access the file, before
         *        resolving redirects.
         */
        public function redirectedFrom( string $from ) {
                $this->redirected = $from;
        }

        /**
         * @stable to override
         * @return bool
         */
        public function isMissing() {
                return false;
        }

        /**
         * Check if this file object is small and can be cached
         * @stable to override
         * @return bool
         */
        public function isCacheable() {
                return true;
        }

        /**
         * Assert that $this->repo is set to a valid FileRepo instance
         */
        protected function assertRepoDefined() {
                if ( !( $this->repo instanceof $this->repoClass ) ) {
                        throw new LogicException( "A {$this->repoClass} object is not set for this File.\n" );
                }
        }

        /**
         * Assert that $this->title is set to a Title
         */
        protected function assertTitleDefined() {
                if ( !( $this->title instanceof Title ) ) {
                        throw new LogicException( "A Title object is not set for this File.\n" );
                }
        }

        /**
         * True if creating thumbnails from the file is large or otherwise resource-intensive.
         * @return bool
         */
        public function isExpensiveToThumbnail() {
                $handler = $this->getHandler();
                return $handler && $handler->isExpensiveToThumbnail( $this );
        }

        /**
         * Whether the thumbnails created on the same server as this code is running.
         * @since 1.25
         * @stable to override
         * @return bool
         */
        public function isTransformedLocally() {
                return true;
        }
}