(bug 18533) Add readonly reason to readonly exception

[mediawiki.git] / includes / filerepo / FileRepo.php

<?php

/**
 * Base class for file repositories
 * Do not instantiate, use a derived class.
 * @ingroup FileRepo
 */
abstract class FileRepo {
        const FILES_ONLY = 1;
        const DELETE_SOURCE = 1;
        const FIND_PRIVATE = 1;
        const FIND_IGNORE_REDIRECT = 2;
        const OVERWRITE = 2;
        const OVERWRITE_SAME = 4;

        var $thumbScriptUrl, $transformVia404;
        var $descBaseUrl, $scriptDirUrl, $articleUrl, $fetchDescription, $initialCapital;
        var $pathDisclosureProtection = 'paranoid';
        var $descriptionCacheExpiry, $apiThumbCacheExpiry, $hashLevels;

        /**
         * Factory functions for creating new files
         * Override these in the base class
         */
        var $fileFactory = false, $oldFileFactory = false;
        var $fileFactoryKey = false, $oldFileFactoryKey = false;

        function __construct( $info ) {
                // Required settings
                $this->name = $info['name'];

                // Optional settings
                $this->initialCapital = true; // by default
                foreach ( array( 'descBaseUrl', 'scriptDirUrl', 'articleUrl', 'fetchDescription',
                        'thumbScriptUrl', 'initialCapital', 'pathDisclosureProtection', 
                        'descriptionCacheExpiry', 'apiThumbCacheExpiry', 'hashLevels' ) as $var )
                {
                        if ( isset( $info[$var] ) ) {
                                $this->$var = $info[$var];
                        }
                }
                $this->transformVia404 = !empty( $info['transformVia404'] );
        }

        /**
         * Determine if a string is an mwrepo:// URL
         */
        static function isVirtualUrl( $url ) {
                return substr( $url, 0, 9 ) == 'mwrepo://';
        }

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

        /**
         * Find an instance of the named file created at the specified time
         * Returns false if the file does not exist. Repositories not supporting
         * version control should return false if the time is specified.
         *
         * @param mixed $title Title object or string
         * @param mixed $time 14-character timestamp, or false for the current version
         */
        function findFile( $title, $time = false, $flags = 0 ) {
                if ( !($title instanceof Title) ) {
                        $title = Title::makeTitleSafe( NS_FILE, $title );
                        if ( !is_object( $title ) ) {
                                return false;
                        }
                }
                # First try the current version of the file to see if it precedes the timestamp
                $img = $this->newFile( $title );
                if ( !$img ) {
                        return false;
                }
                if ( $img->exists() && ( !$time || $img->getTimestamp() == $time ) ) {
                        return $img;
                }
                # Now try an old version of the file
                if ( $time !== false ) {
                        $img = $this->newFile( $title, $time );
                        if ( $img && $img->exists() ) {
                                if ( !$img->isDeleted(File::DELETED_FILE) ) {
                                        return $img;
                                } else if ( ($flags & FileRepo::FIND_PRIVATE) && $img->userCan(File::DELETED_FILE) ) {
                                        return $img;
                                }
                        }
                }
                                
                # Now try redirects
                if ( $flags & FileRepo::FIND_IGNORE_REDIRECT ) {
                        return false;
                }
                $redir = $this->checkRedirect( $title );                
                if( $redir && $redir->getNamespace() == NS_FILE) {
                        $img = $this->newFile( $redir );
                        if( !$img ) {
                                return false;
                        }
                        if( $img->exists() ) {
                                $img->redirectedFrom( $title->getDBkey() );
                                return $img;
                        }
                }
                return false;
        }
        
        /*
         * Find many files at once. 
         * @param array $titles, an array of titles
         * @todo Think of a good way to optionally pass timestamps to this function.
         */
        function findFiles( $titles ) {
                $result = array();
                foreach ( $titles as $index => $title ) {
                        $file = $this->findFile( $title );
                        if ( $file )
                                $result[$file->getTitle()->getDBkey()] = $file;
                }
                return $result;
        }
        
        /**
         * Create a new File object from the local repository
         * @param mixed $sha1 SHA-1 key
         * @param mixed $time Time at which the image was uploaded.
         *                    If this is specified, the returned object will be an
         *                    instance of the repository's old file class instead of
         *                    a current file. Repositories not supporting version
         *                    control should return false if this parameter is set.
         */
        function newFileFromKey( $sha1, $time = false ) {
                if ( $time ) {
                        if ( $this->oldFileFactoryKey ) {
                                return call_user_func( $this->oldFileFactoryKey, $sha1, $this, $time );
                        } else {
                                return false;
                        }
                } else {
                        return call_user_func( $this->fileFactoryKey, $sha1, $this );
                }
        }
        
        /**
         * Find an instance of the file with this key, created at the specified time
         * Returns false if the file does not exist. Repositories not supporting
         * version control should return false if the time is specified.
         *
         * @param string $sha1 string
         * @param mixed $time 14-character timestamp, or false for the current version
         */
        function findFileFromKey( $sha1, $time = false, $flags = 0 ) {
                # First try the current version of the file to see if it precedes the timestamp
                $img = $this->newFileFromKey( $sha1 );
                if ( !$img ) {
                        return false;
                }
                if ( $img->exists() && ( !$time || $img->getTimestamp() == $time ) ) {
                        return $img;
                }
                # Now try an old version of the file
                if ( $time !== false ) {
                        $img = $this->newFileFromKey( $sha1, $time );
                        if ( $img->exists() ) {
                                if ( !$img->isDeleted(File::DELETED_FILE) ) {
                                        return $img;
                                } else if ( ($flags & FileRepo::FIND_PRIVATE) && $img->userCan(File::DELETED_FILE) ) {
                                        return $img;
                                }
                        }
                }
                return false;
        }

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

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

        /**
         * Get the name of an image from its title object
         */
        function getNameFromTitle( $title ) {
                global $wgCapitalLinks;
                if ( $this->initialCapital != $wgCapitalLinks ) {
                        global $wgContLang;
                        $name = $title->getUserCaseDBKey();
                        if ( $this->initialCapital ) {
                                $name = $wgContLang->ucfirst( $name );
                        }
                } else {
                        $name = $title->getDBkey();
                }
                return $name;
        }

        static function getHashPathForLevel( $name, $levels ) {
                if ( $levels == 0 ) {
                        return '';
                } else {
                        $hash = md5( $name );
                        $path = '';
                        for ( $i = 1; $i <= $levels; $i++ ) {
                                $path .= substr( $hash, 0, $i ) . '/';
                        }
                        return $path;
                }
        }
        
        /**
         * Get a relative path including trailing slash, e.g. f/fa/
         * If the repo is not hashed, returns an empty string
         */
        function getHashPath( $name ) {
                return self::getHashPathForLevel( $name, $this->hashLevels );
        }

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

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

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

        /**
         * Store a file to a given destination.
         *
         * @param string $srcPath Source path or virtual URL
         * @param string $dstZone Destination zone
         * @param string $dstRel Destination relative path
         * @param integer $flags Bitwise combination of the following flags:
         *     self::DELETE_SOURCE     Delete the source file after upload
         *     self::OVERWRITE         Overwrite an existing destination file instead of failing
         *     self::OVERWRITE_SAME    Overwrite the file if the destination exists and has the
         *                             same contents as the source
         * @return FileRepoStatus
         */
        function store( $srcPath, $dstZone, $dstRel, $flags = 0 ) {
                $status = $this->storeBatch( array( array( $srcPath, $dstZone, $dstRel ) ), $flags );
                if ( $status->successCount == 0 ) {
                        $status->ok = false;
                }
                return $status;
        }

        /**
         * Store a batch of files
         *
         * @param array $triplets (src,zone,dest) triplets as per store()
         * @param integer $flags Flags as per store
         */
        abstract function storeBatch( $triplets, $flags = 0 );

        /**
         * Pick a random name in the temp zone and store a file to it.
         * Returns a FileRepoStatus object with the URL in the value.
         *
         * @param string $originalName The base name of the file as specified
         *     by the user. The file extension will be maintained.
         * @param string $srcPath The current location of the file.
         */
        abstract function storeTemp( $originalName, $srcPath );

        /**
         * Remove a temporary file or mark it for garbage collection
         * @param string $virtualUrl The virtual URL returned by storeTemp
         * @return boolean True on success, false on failure
         * STUB
         */
        function freeTemp( $virtualUrl ) {
                return true;
        }

        /**
         * Copy or move a file either from the local filesystem or from an mwrepo://
         * virtual URL, into this repository at the specified destination location.
         *
         * Returns a FileRepoStatus object. On success, the value contains "new" or
         * "archived", to indicate whether the file was new with that name.
         *
         * @param string $srcPath The source path or URL
         * @param string $dstRel The destination relative path
         * @param string $archiveRel The relative path where the existing file is to
         *        be archived, if there is one. Relative to the public zone root.
         * @param integer $flags Bitfield, may be FileRepo::DELETE_SOURCE to indicate
         *        that the source file should be deleted if possible
         */
        function publish( $srcPath, $dstRel, $archiveRel, $flags = 0 ) {
                $status = $this->publishBatch( array( array( $srcPath, $dstRel, $archiveRel ) ), $flags );
                if ( $status->successCount == 0 ) {
                        $status->ok = false;
                }
                if ( isset( $status->value[0] ) ) {
                        $status->value = $status->value[0];
                } else {
                        $status->value = false;
                }
                return $status;
        }

        /**
         * Publish a batch of files
         * @param array $triplets (source,dest,archive) triplets as per publish()
         * @param integer $flags Bitfield, may be FileRepo::DELETE_SOURCE to indicate
         *        that the source files should be deleted if possible
         */
        abstract function publishBatch( $triplets, $flags = 0 );

        function fileExists( $file, $flags = 0 ) {
                $result = $this->fileExistsBatch( array( $file ), $flags );
                return $result[0];
        }

        /**
         * Checks existence of an array of files.
         *
         * @param array $files URLs (or paths) of files to check
         * @param integer $flags Bitwise combination of the following flags:
         *     self::FILES_ONLY     Mark file as existing only if it is a file (not directory)
         * @return Either array of files and existence flags, or false
         */
        abstract function fileExistsBatch( $files, $flags = 0 );

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

        /**
         * Move a file to the deletion archive.
         * If no valid deletion archive exists, this may either delete the file
         * or throw an exception, depending on the preference of the repository
         * @param mixed $srcRel Relative path for the file to be deleted
         * @param mixed $archiveRel Relative path for the archive location.
         *        Relative to a private archive directory.
         * @return WikiError object (wikitext-formatted), or true for success
         */
        function delete( $srcRel, $archiveRel ) {
                return $this->deleteBatch( array( array( $srcRel, $archiveRel ) ) );
        }

        /**
         * Get properties of a file with a given virtual URL
         * The virtual URL must refer to this repo
         * Properties should ultimately be obtained via File::getPropsFromPath()
         */
        abstract function getFileProps( $virtualUrl );

        /**
         * Call a callback function for every file in the repository
         * May use either the database or the filesystem
         * STUB
         */
        function enumFiles( $callback ) {
                throw new MWException( 'enumFiles is not supported by ' . get_class( $this ) );
        }

        /**
         * Determine if a relative path is valid, i.e. not blank or involving directory traveral
         */
        function validateFilename( $filename ) {
                if ( strval( $filename ) == '' ) {
                        return false;
                }
                if ( wfIsWindows() ) {
                        $filename = strtr( $filename, '\\', '/' );
                }
                /**
                 * Use the same traversal protection as Title::secureAndSplit()
                 */
                if ( strpos( $filename, '.' ) !== false &&
                     ( $filename === '.' || $filename === '..' ||
                       strpos( $filename, './' ) === 0  ||
                       strpos( $filename, '../' ) === 0 ||
                       strpos( $filename, '/./' ) !== false ||
                       strpos( $filename, '/../' ) !== false ) )
                {
                        return false;
                } else {
                        return true;
                }
        }

        /**#@+
         * Path disclosure protection functions
         */
        function paranoidClean( $param ) { return '[hidden]'; }
        function passThrough( $param ) { return $param; }

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

        /**
         * Create a new fatal error
         */
        function newFatal( $message /*, parameters...*/ ) {
                $params = func_get_args();
                array_unshift( $params, $this );
                return call_user_func_array( array( 'FileRepoStatus', 'newFatal' ), $params );
        }

        /**
         * Create a new good result
         */
        function newGood( $value = null ) {
                return FileRepoStatus::newGood( $this, $value );
        }

        /**
         * Delete files in the deleted directory if they are not referenced in the filearchive table
         * STUB
         */
        function cleanupDeletedBatch( $storageKeys ) {}

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

        /**
         * Invalidates image redirect cache related to that image
         * Doesn't do anything for repositories that don't support image redirects.
         * 
         * STUB
         * @param Title $title Title of image
         */     
        function invalidateImageRedirect( $title ) {}
        
        /**
         * Get an array or iterator of file objects for files that have a given 
         * SHA-1 content hash.
         *
         * STUB
         */
        function findBySha1( $hash ) {
                return array();
        }
        
        /**
         * Get the human-readable name of the repo. 
         * @return string
         */
        public function getDisplayName() {
                // We don't name our own repo, return nothing
                if ( $this->name == 'local' ) {
                        return null;
                }
                $repoName = wfMsg( 'shared-repo-name-' . $this->name );
                if ( !wfEmptyMsg( 'shared-repo-name-' . $this->name, $repoName ) ) {
                        return $repoName;
                }
                return wfMsg( 'shared-repo' ); 
        }
        
        /**
         * Get a key on the primary cache for this repository.
         * Returns false if the repository's cache is not accessible at this site. 
         * The parameters are the parts of the key, as for wfMemcKey().
         *
         * STUB
         */
        function getSharedCacheKey( /*...*/ ) {
                return false;
        }

        /**
         * Get a key for this repo in the local cache domain. These cache keys are 
         * not shared with remote instances of the repo.
         * The parameters are the parts of the key, as for wfMemcKey().
         */
        function getLocalCacheKey( /*...*/ ) {
                $args = func_get_args();
                array_unshift( $args, 'filerepo', $this->getName() );
                return call_user_func_array( 'wfMemcKey', $args );
        }
}