UploadBase.php

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<?php
abstract class UploadBase {
    protected $mTempPath;
    protected $tempFileObj;

    protected $mDesiredDestName, $mDestName, $mRemoveTempFile, $mSourceType;
    protected $mTitle = false, $mTitleError = 0;
    protected $mFilteredName, $mFinalExtension;
    protected $mLocalFile, $mStashFile, $mFileSize, $mFileProps;
    protected $mBlackListedExtensions;
    protected $mJavaDetected, $mSVGNSError;

    protected static $safeXmlEncodings = [
        'UTF-8',
        'ISO-8859-1',
        'ISO-8859-2',
        'UTF-16',
        'UTF-32',
        'WINDOWS-1250',
        'WINDOWS-1251',
        'WINDOWS-1252',
        'WINDOWS-1253',
        'WINDOWS-1254',
        'WINDOWS-1255',
        'WINDOWS-1256',
        'WINDOWS-1257',
        'WINDOWS-1258',
    ];

    const SUCCESS = 0;
    const OK = 0;
    const EMPTY_FILE = 3;
    const MIN_LENGTH_PARTNAME = 4;
    const ILLEGAL_FILENAME = 5;
    const OVERWRITE_EXISTING_FILE = 7; # Not used anymore; handled by verifyTitlePermissions()
    const FILETYPE_MISSING = 8;
    const FILETYPE_BADTYPE = 9;
    const VERIFICATION_ERROR = 10;
    const HOOK_ABORTED = 11;
    const FILE_TOO_LARGE = 12;
    const WINDOWS_NONASCII_FILENAME = 13;
    const FILENAME_TOO_LONG = 14;

    public function getVerificationErrorCode( $error ) {
        $code_to_status = [
            self::EMPTY_FILE => 'empty-file',
            self::FILE_TOO_LARGE => 'file-too-large',
            self::FILETYPE_MISSING => 'filetype-missing',
            self::FILETYPE_BADTYPE => 'filetype-banned',
            self::MIN_LENGTH_PARTNAME => 'filename-tooshort',
            self::ILLEGAL_FILENAME => 'illegal-filename',
            self::OVERWRITE_EXISTING_FILE => 'overwrite',
            self::VERIFICATION_ERROR => 'verification-error',
            self::HOOK_ABORTED => 'hookaborted',
            self::WINDOWS_NONASCII_FILENAME => 'windows-nonascii-filename',
            self::FILENAME_TOO_LONG => 'filename-toolong',
        ];
        if ( isset( $code_to_status[$error] ) ) {
            return $code_to_status[$error];
        }

        return 'unknown-error';
    }

    public static function isEnabled() {
        global $wgEnableUploads;

        if ( !$wgEnableUploads ) {
            return false;
        }

        # Check php's file_uploads setting
        return wfIsHHVM() || wfIniGetBool( 'file_uploads' );
    }

    public static function isAllowed( $user ) {
        foreach ( [ 'upload', 'edit' ] as $permission ) {
            if ( !$user->isAllowed( $permission ) ) {
                return $permission;
            }
        }

        return true;
    }

    public static function isThrottled( $user ) {
        return $user->pingLimiter( 'upload' );
    }

    // Upload handlers. Should probably just be a global.
    private static $uploadHandlers = [ 'Stash', 'File', 'Url' ];

    public static function createFromRequest( &$request, $type = null ) {
        $type = $type ? $type : $request->getVal( 'wpSourceType', 'File' );

        if ( !$type ) {
            return null;
        }

        // Get the upload class
        $type = ucfirst( $type );

        // Give hooks the chance to handle this request
        $className = null;
        Hooks::run( 'UploadCreateFromRequest', [ $type, &$className ] );
        if ( is_null( $className ) ) {
            $className = 'UploadFrom' . $type;
            wfDebug( __METHOD__ . ": class name: $className\n" );
            if ( !in_array( $type, self::$uploadHandlers ) ) {
                return null;
            }
        }

        // Check whether this upload class is enabled
        if ( !call_user_func( [ $className, 'isEnabled' ] ) ) {
            return null;
        }

        // Check whether the request is valid
        if ( !call_user_func( [ $className, 'isValidRequest' ], $request ) ) {
            return null;
        }

        $handler = new $className;

        $handler->initializeFromRequest( $request );

        return $handler;
    }

    public static function isValidRequest( $request ) {
        return false;
    }

    public function __construct() {
    }

    public function getSourceType() {
        return null;
    }

    public function initializePathInfo( $name, $tempPath, $fileSize, $removeTempFile = false ) {
        $this->mDesiredDestName = $name;
        if ( FileBackend::isStoragePath( $tempPath ) ) {
            throw new MWException( __METHOD__ . " given storage path `$tempPath`." );
        }

        $this->setTempFile( $tempPath, $fileSize );
        $this->mRemoveTempFile = $removeTempFile;
    }

    abstract public function initializeFromRequest( &$request );

    protected function setTempFile( $tempPath, $fileSize = null ) {
        $this->mTempPath = $tempPath;
        $this->mFileSize = $fileSize ?: null;
        if ( strlen( $this->mTempPath ) && file_exists( $this->mTempPath ) ) {
            $this->tempFileObj = new TempFSFile( $this->mTempPath );
            if ( !$fileSize ) {
                $this->mFileSize = filesize( $this->mTempPath );
            }
        } else {
            $this->tempFileObj = null;
        }
    }

    public function fetchFile() {
        return Status::newGood();
    }

    public function isEmptyFile() {
        return empty( $this->mFileSize );
    }

    public function getFileSize() {
        return $this->mFileSize;
    }

    public function getTempFileSha1Base36() {
        return FSFile::getSha1Base36FromPath( $this->mTempPath );
    }

    function getRealPath( $srcPath ) {
        $repo = RepoGroup::singleton()->getLocalRepo();
        if ( $repo->isVirtualUrl( $srcPath ) ) {
            $tmpFile = $repo->getLocalCopy( $srcPath );
            if ( $tmpFile ) {
                $tmpFile->bind( $this ); // keep alive with $this
            }
            $path = $tmpFile ? $tmpFile->getPath() : false;
        } else {
            $path = $srcPath;
        }

        return $path;
    }

    public function verifyUpload() {

        if ( $this->isEmptyFile() ) {
            return [ 'status' => self::EMPTY_FILE ];
        }

        $maxSize = self::getMaxUploadSize( $this->getSourceType() );
        if ( $this->mFileSize > $maxSize ) {
            return [
                'status' => self::FILE_TOO_LARGE,
                'max' => $maxSize,
            ];
        }

        $verification = $this->verifyFile();
        if ( $verification !== true ) {
            return [
                'status' => self::VERIFICATION_ERROR,
                'details' => $verification
            ];
        }

        $result = $this->validateName();
        if ( $result !== true ) {
            return $result;
        }

        $error = '';
        if ( !Hooks::run( 'UploadVerification',
            [ $this->mDestName, $this->mTempPath, &$error ], '1.28' )
        ) {
            return [ 'status' => self::HOOK_ABORTED, 'error' => $error ];
        }

        return [ 'status' => self::OK ];
    }

    public function validateName() {
        $nt = $this->getTitle();
        if ( is_null( $nt ) ) {
            $result = [ 'status' => $this->mTitleError ];
            if ( $this->mTitleError == self::ILLEGAL_FILENAME ) {
                $result['filtered'] = $this->mFilteredName;
            }
            if ( $this->mTitleError == self::FILETYPE_BADTYPE ) {
                $result['finalExt'] = $this->mFinalExtension;
                if ( count( $this->mBlackListedExtensions ) ) {
                    $result['blacklistedExt'] = $this->mBlackListedExtensions;
                }
            }

            return $result;
        }
        $this->mDestName = $this->getLocalFile()->getName();

        return true;
    }

    protected function verifyMimeType( $mime ) {
        global $wgVerifyMimeType;
        if ( $wgVerifyMimeType ) {
            wfDebug( "mime: <$mime> extension: <{$this->mFinalExtension}>\n" );
            global $wgMimeTypeBlacklist;
            if ( $this->checkFileExtension( $mime, $wgMimeTypeBlacklist ) ) {
                return [ 'filetype-badmime', $mime ];
            }

            # Check what Internet Explorer would detect
            $fp = fopen( $this->mTempPath, 'rb' );
            $chunk = fread( $fp, 256 );
            fclose( $fp );

            $magic = MimeMagic::singleton();
            $extMime = $magic->guessTypesForExtension( $this->mFinalExtension );
            $ieTypes = $magic->getIEMimeTypes( $this->mTempPath, $chunk, $extMime );
            foreach ( $ieTypes as $ieType ) {
                if ( $this->checkFileExtension( $ieType, $wgMimeTypeBlacklist ) ) {
                    return [ 'filetype-bad-ie-mime', $ieType ];
                }
            }
        }

        return true;
    }

    protected function verifyFile() {
        global $wgVerifyMimeType, $wgDisableUploadScriptChecks;

        $status = $this->verifyPartialFile();
        if ( $status !== true ) {
            return $status;
        }

        $mwProps = new MWFileProps( MimeMagic::singleton() );
        $this->mFileProps = $mwProps->getPropsFromPath( $this->mTempPath, $this->mFinalExtension );
        $mime = $this->mFileProps['mime'];

        if ( $wgVerifyMimeType ) {
            # XXX: Missing extension will be caught by validateName() via getTitle()
            if ( $this->mFinalExtension != '' && !$this->verifyExtension( $mime, $this->mFinalExtension ) ) {
                return [ 'filetype-mime-mismatch', $this->mFinalExtension, $mime ];
            }
        }

        # check for htmlish code and javascript
        if ( !$wgDisableUploadScriptChecks ) {
            if ( $this->mFinalExtension == 'svg' || $mime == 'image/svg+xml' ) {
                $svgStatus = $this->detectScriptInSvg( $this->mTempPath, false );
                if ( $svgStatus !== false ) {
                    return $svgStatus;
                }
            }
        }

        $handler = MediaHandler::getHandler( $mime );
        if ( $handler ) {
            $handlerStatus = $handler->verifyUpload( $this->mTempPath );
            if ( !$handlerStatus->isOK() ) {
                $errors = $handlerStatus->getErrorsArray();

                return reset( $errors );
            }
        }

        $error = true;
        Hooks::run( 'UploadVerifyFile', [ $this, $mime, &$error ] );
        if ( $error !== true ) {
            if ( !is_array( $error ) ) {
                $error = [ $error ];
            }
            return $error;
        }

        wfDebug( __METHOD__ . ": all clear; passing.\n" );

        return true;
    }

    protected function verifyPartialFile() {
        global $wgAllowJavaUploads, $wgDisableUploadScriptChecks;

        # getTitle() sets some internal parameters like $this->mFinalExtension
        $this->getTitle();

        $mwProps = new MWFileProps( MimeMagic::singleton() );
        $this->mFileProps = $mwProps->getPropsFromPath( $this->mTempPath, $this->mFinalExtension );

        # check MIME type, if desired
        $mime = $this->mFileProps['file-mime'];
        $status = $this->verifyMimeType( $mime );
        if ( $status !== true ) {
            return $status;
        }

        # check for htmlish code and javascript
        if ( !$wgDisableUploadScriptChecks ) {
            if ( self::detectScript( $this->mTempPath, $mime, $this->mFinalExtension ) ) {
                return [ 'uploadscripted' ];
            }
            if ( $this->mFinalExtension == 'svg' || $mime == 'image/svg+xml' ) {
                $svgStatus = $this->detectScriptInSvg( $this->mTempPath, true );
                if ( $svgStatus !== false ) {
                    return $svgStatus;
                }
            }
        }

        # Check for Java applets, which if uploaded can bypass cross-site
        # restrictions.
        if ( !$wgAllowJavaUploads ) {
            $this->mJavaDetected = false;
            $zipStatus = ZipDirectoryReader::read( $this->mTempPath,
                [ $this, 'zipEntryCallback' ] );
            if ( !$zipStatus->isOK() ) {
                $errors = $zipStatus->getErrorsArray();
                $error = reset( $errors );
                if ( $error[0] !== 'zip-wrong-format' ) {
                    return $error;
                }
            }
            if ( $this->mJavaDetected ) {
                return [ 'uploadjava' ];
            }
        }

        # Scan the uploaded file for viruses
        $virus = $this->detectVirus( $this->mTempPath );
        if ( $virus ) {
            return [ 'uploadvirus', $virus ];
        }

        return true;
    }

    function zipEntryCallback( $entry ) {
        $names = [ $entry['name'] ];

        // If there is a null character, cut off the name at it, because JDK's
        // ZIP_GetEntry() uses strcmp() if the name hashes match. If a file name
        // were constructed which had ".class\0" followed by a string chosen to
        // make the hash collide with the truncated name, that file could be
        // returned in response to a request for the .class file.
        $nullPos = strpos( $entry['name'], "\000" );
        if ( $nullPos !== false ) {
            $names[] = substr( $entry['name'], 0, $nullPos );
        }

        // If there is a trailing slash in the file name, we have to strip it,
        // because that's what ZIP_GetEntry() does.
        if ( preg_grep( '!\.class/?$!', $names ) ) {
            $this->mJavaDetected = true;
        }
    }

    public function verifyPermissions( $user ) {
        return $this->verifyTitlePermissions( $user );
    }

    public function verifyTitlePermissions( $user ) {
        $nt = $this->getTitle();
        if ( is_null( $nt ) ) {
            return true;
        }
        $permErrors = $nt->getUserPermissionsErrors( 'edit', $user );
        $permErrorsUpload = $nt->getUserPermissionsErrors( 'upload', $user );
        if ( !$nt->exists() ) {
            $permErrorsCreate = $nt->getUserPermissionsErrors( 'create', $user );
        } else {
            $permErrorsCreate = [];
        }
        if ( $permErrors || $permErrorsUpload || $permErrorsCreate ) {
            $permErrors = array_merge( $permErrors, wfArrayDiff2( $permErrorsUpload, $permErrors ) );
            $permErrors = array_merge( $permErrors, wfArrayDiff2( $permErrorsCreate, $permErrors ) );

            return $permErrors;
        }

        $overwriteError = $this->checkOverwrite( $user );
        if ( $overwriteError !== true ) {
            return [ $overwriteError ];
        }

        return true;
    }

    public function checkWarnings() {
        global $wgLang;

        $warnings = [];

        $localFile = $this->getLocalFile();
        $localFile->load( File::READ_LATEST );
        $filename = $localFile->getName();

        $comparableName = str_replace( ' ', '_', $this->mDesiredDestName );
        $comparableName = Title::capitalize( $comparableName, NS_FILE );

        if ( $this->mDesiredDestName != $filename && $comparableName != $filename ) {
            $warnings['badfilename'] = $filename;
        }

        // Check whether the file extension is on the unwanted list
        global $wgCheckFileExtensions, $wgFileExtensions;
        if ( $wgCheckFileExtensions ) {
            $extensions = array_unique( $wgFileExtensions );
            if ( !$this->checkFileExtension( $this->mFinalExtension, $extensions ) ) {
                $warnings['filetype-unwanted-type'] = [ $this->mFinalExtension,
                    $wgLang->commaList( $extensions ), count( $extensions ) ];
            }
        }

        global $wgUploadSizeWarning;
        if ( $wgUploadSizeWarning && ( $this->mFileSize > $wgUploadSizeWarning ) ) {
            $warnings['large-file'] = [ $wgUploadSizeWarning, $this->mFileSize ];
        }

        if ( $this->mFileSize == 0 ) {
            $warnings['empty-file'] = true;
        }

        $hash = $this->getTempFileSha1Base36();
        $exists = self::getExistsWarning( $localFile );
        if ( $exists !== false ) {
            $warnings['exists'] = $exists;

            // check if file is an exact duplicate of current file version
            if ( $hash === $localFile->getSha1() ) {
                $warnings['no-change'] = $localFile;
            }

            // check if file is an exact duplicate of older versions of this file
            $history = $localFile->getHistory();
            foreach ( $history as $oldFile ) {
                if ( $hash === $oldFile->getSha1() ) {
                    $warnings['duplicate-version'][] = $oldFile;
                }
            }
        }

        if ( $localFile->wasDeleted() && !$localFile->exists() ) {
            $warnings['was-deleted'] = $filename;
        }

        // Check dupes against existing files
        $dupes = RepoGroup::singleton()->findBySha1( $hash );
        $title = $this->getTitle();
        // Remove all matches against self
        foreach ( $dupes as $key => $dupe ) {
            if ( $title->equals( $dupe->getTitle() ) ) {
                unset( $dupes[$key] );
            }
        }
        if ( $dupes ) {
            $warnings['duplicate'] = $dupes;
        }

        // Check dupes against archives
        $archivedFile = new ArchivedFile( null, 0, '', $hash );
        if ( $archivedFile->getID() > 0 ) {
            if ( $archivedFile->userCan( File::DELETED_FILE ) ) {
                $warnings['duplicate-archive'] = $archivedFile->getName();
            } else {
                $warnings['duplicate-archive'] = '';
            }
        }

        return $warnings;
    }

    public function performUpload( $comment, $pageText, $watch, $user, $tags = [] ) {
        $this->getLocalFile()->load( File::READ_LATEST );
        $props = $this->mFileProps;

        $error = null;
        Hooks::run( 'UploadVerifyUpload', [ $this, $user, $props, $comment, $pageText, &$error ] );
        if ( $error ) {
            if ( !is_array( $error ) ) {
                $error = [ $error ];
            }
            return call_user_func_array( 'Status::newFatal', $error );
        }

        $status = $this->getLocalFile()->upload(
            $this->mTempPath,
            $comment,
            $pageText,
            File::DELETE_SOURCE,
            $props,
            false,
            $user,
            $tags
        );

        if ( $status->isGood() ) {
            if ( $watch ) {
                WatchAction::doWatch(
                    $this->getLocalFile()->getTitle(),
                    $user,
                    User::IGNORE_USER_RIGHTS
                );
            }
            Hooks::run( 'UploadComplete', [ &$this ] );

            $this->postProcessUpload();
        }

        return $status;
    }

    public function postProcessUpload() {
    }

    public function getTitle() {
        if ( $this->mTitle !== false ) {
            return $this->mTitle;
        }
        if ( !is_string( $this->mDesiredDestName ) ) {
            $this->mTitleError = self::ILLEGAL_FILENAME;
            $this->mTitle = null;

            return $this->mTitle;
        }
        /* Assume that if a user specified File:Something.jpg, this is an error
         * and that the namespace prefix needs to be stripped of.
         */
        $title = Title::newFromText( $this->mDesiredDestName );
        if ( $title && $title->getNamespace() == NS_FILE ) {
            $this->mFilteredName = $title->getDBkey();
        } else {
            $this->mFilteredName = $this->mDesiredDestName;
        }

        # oi_archive_name is max 255 bytes, which include a timestamp and an
        # exclamation mark, so restrict file name to 240 bytes.
        if ( strlen( $this->mFilteredName ) > 240 ) {
            $this->mTitleError = self::FILENAME_TOO_LONG;
            $this->mTitle = null;

            return $this->mTitle;
        }

        $this->mFilteredName = wfStripIllegalFilenameChars( $this->mFilteredName );
        /* Normalize to title form before we do any further processing */
        $nt = Title::makeTitleSafe( NS_FILE, $this->mFilteredName );
        if ( is_null( $nt ) ) {
            $this->mTitleError = self::ILLEGAL_FILENAME;
            $this->mTitle = null;

            return $this->mTitle;
        }
        $this->mFilteredName = $nt->getDBkey();

        list( $partname, $ext ) = $this->splitExtensions( $this->mFilteredName );

        if ( count( $ext ) ) {
            $this->mFinalExtension = trim( $ext[count( $ext ) - 1] );
        } else {
            $this->mFinalExtension = '';

            # No extension, try guessing one
            $magic = MimeMagic::singleton();
            $mime = $magic->guessMimeType( $this->mTempPath );
            if ( $mime !== 'unknown/unknown' ) {
                # Get a space separated list of extensions
                $extList = $magic->getExtensionsForType( $mime );
                if ( $extList ) {
                    # Set the extension to the canonical extension
                    $this->mFinalExtension = strtok( $extList, ' ' );

                    # Fix up the other variables
                    $this->mFilteredName .= ".{$this->mFinalExtension}";
                    $nt = Title::makeTitleSafe( NS_FILE, $this->mFilteredName );
                    $ext = [ $this->mFinalExtension ];
                }
            }
        }

        /* Don't allow users to override the blacklist (check file extension) */
        global $wgCheckFileExtensions, $wgStrictFileExtensions;
        global $wgFileExtensions, $wgFileBlacklist;

        $blackListedExtensions = $this->checkFileExtensionList( $ext, $wgFileBlacklist );

        if ( $this->mFinalExtension == '' ) {
            $this->mTitleError = self::FILETYPE_MISSING;
            $this->mTitle = null;

            return $this->mTitle;
        } elseif ( $blackListedExtensions ||
            ( $wgCheckFileExtensions && $wgStrictFileExtensions &&
                !$this->checkFileExtension( $this->mFinalExtension, $wgFileExtensions ) )
        ) {
            $this->mBlackListedExtensions = $blackListedExtensions;
            $this->mTitleError = self::FILETYPE_BADTYPE;
            $this->mTitle = null;

            return $this->mTitle;
        }

        // Windows may be broken with special characters, see bug 1780
        if ( !preg_match( '/^[\x0-\x7f]*$/', $nt->getText() )
            && !RepoGroup::singleton()->getLocalRepo()->backendSupportsUnicodePaths()
        ) {
            $this->mTitleError = self::WINDOWS_NONASCII_FILENAME;
            $this->mTitle = null;

            return $this->mTitle;
        }

        # If there was more than one "extension", reassemble the base
        # filename to prevent bogus complaints about length
        if ( count( $ext ) > 1 ) {
            $iterations = count( $ext ) - 1;
            for ( $i = 0; $i < $iterations; $i++ ) {
                $partname .= '.' . $ext[$i];
            }
        }

        if ( strlen( $partname ) < 1 ) {
            $this->mTitleError = self::MIN_LENGTH_PARTNAME;
            $this->mTitle = null;

            return $this->mTitle;
        }

        $this->mTitle = $nt;

        return $this->mTitle;
    }

    public function getLocalFile() {
        if ( is_null( $this->mLocalFile ) ) {
            $nt = $this->getTitle();
            $this->mLocalFile = is_null( $nt ) ? null : wfLocalFile( $nt );
        }

        return $this->mLocalFile;
    }

    public function getStashFile() {
        return $this->mStashFile;
    }

    public function tryStashFile( User $user, $isPartial = false ) {
        if ( !$isPartial ) {
            $error = $this->runUploadStashFileHook( $user );
            if ( $error ) {
                return call_user_func_array( 'Status::newFatal', $error );
            }
        }
        try {
            $file = $this->doStashFile( $user );
            return Status::newGood( $file );
        } catch ( UploadStashException $e ) {
            return Status::newFatal( 'uploadstash-exception', get_class( $e ), $e->getMessage() );
        }
    }

    protected function runUploadStashFileHook( User $user ) {
        $props = $this->mFileProps;
        $error = null;
        Hooks::run( 'UploadStashFile', [ $this, $user, $props, &$error ] );
        if ( $error ) {
            if ( !is_array( $error ) ) {
                $error = [ $error ];
            }
        }
        return $error;
    }

    public function stashFile( User $user = null ) {
        return $this->doStashFile( $user );
    }

    protected function doStashFile( User $user = null ) {
        $stash = RepoGroup::singleton()->getLocalRepo()->getUploadStash( $user );
        $file = $stash->stashFile( $this->mTempPath, $this->getSourceType() );
        $this->mStashFile = $file;

        return $file;
    }

    public function stashFileGetKey() {
        wfDeprecated( __METHOD__, '1.28' );
        return $this->doStashFile()->getFileKey();
    }

    public function stashSession() {
        wfDeprecated( __METHOD__, '1.28' );
        return $this->doStashFile()->getFileKey();
    }

    public function cleanupTempFile() {
        if ( $this->mRemoveTempFile && $this->tempFileObj ) {
            // Delete when all relevant TempFSFile handles go out of scope
            wfDebug( __METHOD__ . ": Marked temporary file '{$this->mTempPath}' for removal\n" );
            $this->tempFileObj->autocollect();
        }
    }

    public function getTempPath() {
        return $this->mTempPath;
    }

    public static function splitExtensions( $filename ) {
        $bits = explode( '.', $filename );
        $basename = array_shift( $bits );

        return [ $basename, $bits ];
    }

    public static function checkFileExtension( $ext, $list ) {
        return in_array( strtolower( $ext ), $list );
    }

    public static function checkFileExtensionList( $ext, $list ) {
        return array_intersect( array_map( 'strtolower', $ext ), $list );
    }

    public static function verifyExtension( $mime, $extension ) {
        $magic = MimeMagic::singleton();

        if ( !$mime || $mime == 'unknown' || $mime == 'unknown/unknown' ) {
            if ( !$magic->isRecognizableExtension( $extension ) ) {
                wfDebug( __METHOD__ . ": passing file with unknown detected mime type; " .
                    "unrecognized extension '$extension', can't verify\n" );

                return true;
            } else {
                wfDebug( __METHOD__ . ": rejecting file with unknown detected mime type; " .
                    "recognized extension '$extension', so probably invalid file\n" );

                return false;
            }
        }

        $match = $magic->isMatchingExtension( $extension, $mime );

        if ( $match === null ) {
            if ( $magic->getTypesForExtension( $extension ) !== null ) {
                wfDebug( __METHOD__ . ": No extension known for $mime, but we know a mime for $extension\n" );

                return false;
            } else {
                wfDebug( __METHOD__ . ": no file extension known for mime type $mime, passing file\n" );

                return true;
            }
        } elseif ( $match === true ) {
            wfDebug( __METHOD__ . ": mime type $mime matches extension $extension, passing file\n" );

            return true;
        } else {
            wfDebug( __METHOD__
                . ": mime type $mime mismatches file extension $extension, rejecting file\n" );

            return false;
        }
    }

    public static function detectScript( $file, $mime, $extension ) {
        global $wgAllowTitlesInSVG;

        # ugly hack: for text files, always look at the entire file.
        # For binary field, just check the first K.

        if ( strpos( $mime, 'text/' ) === 0 ) {
            $chunk = file_get_contents( $file );
        } else {
            $fp = fopen( $file, 'rb' );
            $chunk = fread( $fp, 1024 );
            fclose( $fp );
        }

        $chunk = strtolower( $chunk );

        if ( !$chunk ) {
            return false;
        }

        # decode from UTF-16 if needed (could be used for obfuscation).
        if ( substr( $chunk, 0, 2 ) == "\xfe\xff" ) {
            $enc = 'UTF-16BE';
        } elseif ( substr( $chunk, 0, 2 ) == "\xff\xfe" ) {
            $enc = 'UTF-16LE';
        } else {
            $enc = null;
        }

        if ( $enc ) {
            $chunk = iconv( $enc, "ASCII//IGNORE", $chunk );
        }

        $chunk = trim( $chunk );

        wfDebug( __METHOD__ . ": checking for embedded scripts and HTML stuff\n" );

        # check for HTML doctype
        if ( preg_match( "/<!DOCTYPE *X?HTML/i", $chunk ) ) {
            return true;
        }

        // Some browsers will interpret obscure xml encodings as UTF-8, while
        // PHP/expat will interpret the given encoding in the xml declaration (bug 47304)
        if ( $extension == 'svg' || strpos( $mime, 'image/svg' ) === 0 ) {
            if ( self::checkXMLEncodingMissmatch( $file ) ) {
                return true;
            }
        }

        $tags = [
            '<a href',
            '<body',
            '<head',
            '<html', # also in safari
            '<img',
            '<pre',
            '<script', # also in safari
            '<table'
        ];

        if ( !$wgAllowTitlesInSVG && $extension !== 'svg' && $mime !== 'image/svg' ) {
            $tags[] = '<title';
        }

        foreach ( $tags as $tag ) {
            if ( false !== strpos( $chunk, $tag ) ) {
                wfDebug( __METHOD__ . ": found something that may make it be mistaken for html: $tag\n" );

                return true;
            }
        }

        /*
         * look for JavaScript
         */

        # resolve entity-refs to look at attributes. may be harsh on big files... cache result?
        $chunk = Sanitizer::decodeCharReferences( $chunk );

        # look for script-types
        if ( preg_match( '!type\s*=\s*[\'"]?\s*(?:\w*/)?(?:ecma|java)!sim', $chunk ) ) {
            wfDebug( __METHOD__ . ": found script types\n" );

            return true;
        }

        # look for html-style script-urls
        if ( preg_match( '!(?:href|src|data)\s*=\s*[\'"]?\s*(?:ecma|java)script:!sim', $chunk ) ) {
            wfDebug( __METHOD__ . ": found html-style script urls\n" );

            return true;
        }

        # look for css-style script-urls
        if ( preg_match( '!url\s*\(\s*[\'"]?\s*(?:ecma|java)script:!sim', $chunk ) ) {
            wfDebug( __METHOD__ . ": found css-style script urls\n" );

            return true;
        }

        wfDebug( __METHOD__ . ": no scripts found\n" );

        return false;
    }

    public static function checkXMLEncodingMissmatch( $file ) {
        global $wgSVGMetadataCutoff;
        $contents = file_get_contents( $file, false, null, -1, $wgSVGMetadataCutoff );
        $encodingRegex = '!encoding[ \t\n\r]*=[ \t\n\r]*[\'"](.*?)[\'"]!si';

        if ( preg_match( "!<\?xml\b(.*?)\?>!si", $contents, $matches ) ) {
            if ( preg_match( $encodingRegex, $matches[1], $encMatch )
                && !in_array( strtoupper( $encMatch[1] ), self::$safeXmlEncodings )
            ) {
                wfDebug( __METHOD__ . ": Found unsafe XML encoding '{$encMatch[1]}'\n" );

                return true;
            }
        } elseif ( preg_match( "!<\?xml\b!si", $contents ) ) {
            // Start of XML declaration without an end in the first $wgSVGMetadataCutoff
            // bytes. There shouldn't be a legitimate reason for this to happen.
            wfDebug( __METHOD__ . ": Unmatched XML declaration start\n" );

            return true;
        } elseif ( substr( $contents, 0, 4 ) == "\x4C\x6F\xA7\x94" ) {
            // EBCDIC encoded XML
            wfDebug( __METHOD__ . ": EBCDIC Encoded XML\n" );

            return true;
        }

        // It's possible the file is encoded with multi-byte encoding, so re-encode attempt to
        // detect the encoding in case is specifies an encoding not whitelisted in self::$safeXmlEncodings
        $attemptEncodings = [ 'UTF-16', 'UTF-16BE', 'UTF-32', 'UTF-32BE' ];
        foreach ( $attemptEncodings as $encoding ) {
            MediaWiki\suppressWarnings();
            $str = iconv( $encoding, 'UTF-8', $contents );
            MediaWiki\restoreWarnings();
            if ( $str != '' && preg_match( "!<\?xml\b(.*?)\?>!si", $str, $matches ) ) {
                if ( preg_match( $encodingRegex, $matches[1], $encMatch )
                    && !in_array( strtoupper( $encMatch[1] ), self::$safeXmlEncodings )
                ) {
                    wfDebug( __METHOD__ . ": Found unsafe XML encoding '{$encMatch[1]}'\n" );

                    return true;
                }
            } elseif ( $str != '' && preg_match( "!<\?xml\b!si", $str ) ) {
                // Start of XML declaration without an end in the first $wgSVGMetadataCutoff
                // bytes. There shouldn't be a legitimate reason for this to happen.
                wfDebug( __METHOD__ . ": Unmatched XML declaration start\n" );

                return true;
            }
        }

        return false;
    }

    protected function detectScriptInSvg( $filename, $partial ) {
        $this->mSVGNSError = false;
        $check = new XmlTypeCheck(
            $filename,
            [ $this, 'checkSvgScriptCallback' ],
            true,
            [
                'processing_instruction_handler' => 'UploadBase::checkSvgPICallback',
                'external_dtd_handler' => 'UploadBase::checkSvgExternalDTD',
            ]
        );
        if ( $check->wellFormed !== true ) {
            // Invalid xml (bug 58553)
            // But only when non-partial (bug 65724)
            return $partial ? false : [ 'uploadinvalidxml' ];
        } elseif ( $check->filterMatch ) {
            if ( $this->mSVGNSError ) {
                return [ 'uploadscriptednamespace', $this->mSVGNSError ];
            }

            return $check->filterMatchType;
        }

        return false;
    }

    public static function checkSvgPICallback( $target, $data ) {
        // Don't allow external stylesheets (bug 57550)
        if ( preg_match( '/xml-stylesheet/i', $target ) ) {
            return [ 'upload-scripted-pi-callback' ];
        }

        return false;
    }

    public static function checkSvgExternalDTD( $type, $publicId, $systemId ) {
        // This doesn't include the XHTML+MathML+SVG doctype since we don't
        // allow XHTML anyways.
        $allowedDTDs = [
            'http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd',
            'http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd',
            'http://www.w3.org/Graphics/SVG/1.1/DTD/svg11-basic.dtd',
            'http://www.w3.org/Graphics/SVG/1.1/DTD/svg11-tiny.dtd',
            // https://phabricator.wikimedia.org/T168856
            'http://www.w3.org/TR/2001/PR-SVG-20010719/DTD/svg10.dtd',
        ];
        if ( $type !== 'PUBLIC'
            || !in_array( $systemId, $allowedDTDs )
            || strpos( $publicId, "-//W3C//" ) !== 0
        ) {
            return [ 'upload-scripted-dtd' ];
        }
        return false;
    }

    public function checkSvgScriptCallback( $element, $attribs, $data = null ) {

        list( $namespace, $strippedElement ) = $this->splitXmlNamespace( $element );

        // We specifically don't include:
        // http://www.w3.org/1999/xhtml (bug 60771)
        static $validNamespaces = [
            '',
            'adobe:ns:meta/',
            'http://creativecommons.org/ns#',
            'http://inkscape.sourceforge.net/dtd/sodipodi-0.dtd',
            'http://ns.adobe.com/adobeillustrator/10.0/',
            'http://ns.adobe.com/adobesvgviewerextensions/3.0/',
            'http://ns.adobe.com/extensibility/1.0/',
            'http://ns.adobe.com/flows/1.0/',
            'http://ns.adobe.com/illustrator/1.0/',
            'http://ns.adobe.com/imagereplacement/1.0/',
            'http://ns.adobe.com/pdf/1.3/',
            'http://ns.adobe.com/photoshop/1.0/',
            'http://ns.adobe.com/saveforweb/1.0/',
            'http://ns.adobe.com/variables/1.0/',
            'http://ns.adobe.com/xap/1.0/',
            'http://ns.adobe.com/xap/1.0/g/',
            'http://ns.adobe.com/xap/1.0/g/img/',
            'http://ns.adobe.com/xap/1.0/mm/',
            'http://ns.adobe.com/xap/1.0/rights/',
            'http://ns.adobe.com/xap/1.0/stype/dimensions#',
            'http://ns.adobe.com/xap/1.0/stype/font#',
            'http://ns.adobe.com/xap/1.0/stype/manifestitem#',
            'http://ns.adobe.com/xap/1.0/stype/resourceevent#',
            'http://ns.adobe.com/xap/1.0/stype/resourceref#',
            'http://ns.adobe.com/xap/1.0/t/pg/',
            'http://purl.org/dc/elements/1.1/',
            'http://purl.org/dc/elements/1.1',
            'http://schemas.microsoft.com/visio/2003/svgextensions/',
            'http://sodipodi.sourceforge.net/dtd/sodipodi-0.dtd',
            'http://taptrix.com/inkpad/svg_extensions',
            'http://web.resource.org/cc/',
            'http://www.freesoftware.fsf.org/bkchem/cdml',
            'http://www.inkscape.org/namespaces/inkscape',
            'http://www.opengis.net/gml',
            'http://www.w3.org/1999/02/22-rdf-syntax-ns#',
            'http://www.w3.org/2000/svg',
            'http://www.w3.org/tr/rec-rdf-syntax/',
        ];

        if ( !in_array( $namespace, $validNamespaces ) ) {
            wfDebug( __METHOD__ . ": Non-svg namespace '$namespace' in uploaded file.\n" );
            $this->mSVGNSError = $namespace;

            return true;
        }

        /*
         * check for elements that can contain javascript
         */
        if ( $strippedElement == 'script' ) {
            wfDebug( __METHOD__ . ": Found script element '$element' in uploaded file.\n" );

            return [ 'uploaded-script-svg', $strippedElement ];
        }

        # e.g., <svg xmlns="http://www.w3.org/2000/svg">
        #  <handler xmlns:ev="http://www.w3.org/2001/xml-events" ev:event="load">alert(1)</handler> </svg>
        if ( $strippedElement == 'handler' ) {
            wfDebug( __METHOD__ . ": Found scriptable element '$element' in uploaded file.\n" );

            return [ 'uploaded-script-svg', $strippedElement ];
        }

        # SVG reported in Feb '12 that used xml:stylesheet to generate javascript block
        if ( $strippedElement == 'stylesheet' ) {
            wfDebug( __METHOD__ . ": Found scriptable element '$element' in uploaded file.\n" );

            return [ 'uploaded-script-svg', $strippedElement ];
        }

        # Block iframes, in case they pass the namespace check
        if ( $strippedElement == 'iframe' ) {
            wfDebug( __METHOD__ . ": iframe in uploaded file.\n" );

            return [ 'uploaded-script-svg', $strippedElement ];
        }

        # Check <style> css
        if ( $strippedElement == 'style'
            && self::checkCssFragment( Sanitizer::normalizeCss( $data ) )
        ) {
            wfDebug( __METHOD__ . ": hostile css in style element.\n" );
            return [ 'uploaded-hostile-svg' ];
        }

        foreach ( $attribs as $attrib => $value ) {
            $stripped = $this->stripXmlNamespace( $attrib );
            $value = strtolower( $value );

            if ( substr( $stripped, 0, 2 ) == 'on' ) {
                wfDebug( __METHOD__
                    . ": Found event-handler attribute '$attrib'='$value' in uploaded file.\n" );

                return [ 'uploaded-event-handler-on-svg', $attrib, $value ];
            }

            # Do not allow relative links, or unsafe url schemas.
            # For <a> tags, only data:, http: and https: and same-document
            # fragment links are allowed. For all other tags, only data:
            # and fragment are allowed.
            if ( $stripped == 'href'
                && strpos( $value, 'data:' ) !== 0
                && strpos( $value, '#' ) !== 0
            ) {
                if ( !( $strippedElement === 'a'
                    && preg_match( '!^https?://!i', $value ) )
                ) {
                    wfDebug( __METHOD__ . ": Found href attribute <$strippedElement "
                        . "'$attrib'='$value' in uploaded file.\n" );

                    return [ 'uploaded-href-attribute-svg', $strippedElement, $attrib, $value ];
                }
            }

            # only allow data: targets that should be safe. This prevents vectors like,
            # image/svg, text/xml, application/xml, and text/html, which can contain scripts
            if ( $stripped == 'href' && strncasecmp( 'data:', $value, 5 ) === 0 ) {
                // rfc2397 parameters. This is only slightly slower than (;[\w;]+)*.
                // @codingStandardsIgnoreStart Generic.Files.LineLength
                $parameters = '(?>;[a-zA-Z0-9\!#$&\'*+.^_`{|}~-]+=(?>[a-zA-Z0-9\!#$&\'*+.^_`{|}~-]+|"(?>[\0-\x0c\x0e-\x21\x23-\x5b\x5d-\x7f]+|\\\\[\0-\x7f])*"))*(?:;base64)?';
                // @codingStandardsIgnoreEnd

                if ( !preg_match( "!^data:\s*image/(gif|jpeg|jpg|png)$parameters,!i", $value ) ) {
                    wfDebug( __METHOD__ . ": Found href to unwhitelisted data: uri "
                        . "\"<$strippedElement '$attrib'='$value'...\" in uploaded file.\n" );
                    return [ 'uploaded-href-unsafe-target-svg', $strippedElement, $attrib, $value ];
                }
            }

            # Change href with animate from (http://html5sec.org/#137).
            if ( $stripped === 'attributename'
                && $strippedElement === 'animate'
                && $this->stripXmlNamespace( $value ) == 'href'
            ) {
                wfDebug( __METHOD__ . ": Found animate that might be changing href using from "
                    . "\"<$strippedElement '$attrib'='$value'...\" in uploaded file.\n" );

                return [ 'uploaded-animate-svg', $strippedElement, $attrib, $value ];
            }

            # use set/animate to add event-handler attribute to parent
            if ( ( $strippedElement == 'set' || $strippedElement == 'animate' )
                && $stripped == 'attributename'
                && substr( $value, 0, 2 ) == 'on'
            ) {
                wfDebug( __METHOD__ . ": Found svg setting event-handler attribute with "
                    . "\"<$strippedElement $stripped='$value'...\" in uploaded file.\n" );

                return [ 'uploaded-setting-event-handler-svg', $strippedElement, $stripped, $value ];
            }

            # use set to add href attribute to parent element
            if ( $strippedElement == 'set'
                && $stripped == 'attributename'
                && strpos( $value, 'href' ) !== false
            ) {
                wfDebug( __METHOD__ . ": Found svg setting href attribute '$value' in uploaded file.\n" );

                return [ 'uploaded-setting-href-svg' ];
            }

            # use set to add a remote / data / script target to an element
            if ( $strippedElement == 'set'
                && $stripped == 'to'
                && preg_match( '!(http|https|data|script):!sim', $value )
            ) {
                wfDebug( __METHOD__ . ": Found svg setting attribute to '$value' in uploaded file.\n" );

                return [ 'uploaded-wrong-setting-svg', $value ];
            }

            # use handler attribute with remote / data / script
            if ( $stripped == 'handler' && preg_match( '!(http|https|data|script):!sim', $value ) ) {
                wfDebug( __METHOD__ . ": Found svg setting handler with remote/data/script "
                    . "'$attrib'='$value' in uploaded file.\n" );

                return [ 'uploaded-setting-handler-svg', $attrib, $value ];
            }

            # use CSS styles to bring in remote code
            if ( $stripped == 'style'
                && self::checkCssFragment( Sanitizer::normalizeCss( $value ) )
            ) {
                wfDebug( __METHOD__ . ": Found svg setting a style with "
                    . "remote url '$attrib'='$value' in uploaded file.\n" );
                return [ 'uploaded-remote-url-svg', $attrib, $value ];
            }

            # Several attributes can include css, css character escaping isn't allowed
            $cssAttrs = [ 'font', 'clip-path', 'fill', 'filter', 'marker',
                'marker-end', 'marker-mid', 'marker-start', 'mask', 'stroke' ];
            if ( in_array( $stripped, $cssAttrs )
                && self::checkCssFragment( $value )
            ) {
                wfDebug( __METHOD__ . ": Found svg setting a style with "
                    . "remote url '$attrib'='$value' in uploaded file.\n" );
                return [ 'uploaded-remote-url-svg', $attrib, $value ];
            }

            # image filters can pull in url, which could be svg that executes scripts
            if ( $strippedElement == 'image'
                && $stripped == 'filter'
                && preg_match( '!url\s*\(!sim', $value )
            ) {
                wfDebug( __METHOD__ . ": Found image filter with url: "
                    . "\"<$strippedElement $stripped='$value'...\" in uploaded file.\n" );

                return [ 'uploaded-image-filter-svg', $strippedElement, $stripped, $value ];
            }
        }

        return false; // No scripts detected
    }

    private static function checkCssFragment( $value ) {

        # Forbid external stylesheets, for both reliability and to protect viewer's privacy
        if ( stripos( $value, '@import' ) !== false ) {
            return true;
        }

        # We allow @font-face to embed fonts with data: urls, so we snip the string
        # 'url' out so this case won't match when we check for urls below
        $pattern = '!(@font-face\s*{[^}]*src:)url(\("data:;base64,)!im';
        $value = preg_replace( $pattern, '$1$2', $value );

        # Check for remote and executable CSS. Unlike in Sanitizer::checkCss, the CSS
        # properties filter and accelerator don't seem to be useful for xss in SVG files.
        # Expression and -o-link don't seem to work either, but filtering them here in case.
        # Additionally, we catch remote urls like url("http:..., url('http:..., url(http:...,
        # but not local ones such as url("#..., url('#..., url(#....
        if ( preg_match( '!expression
                | -o-link\s*:
                | -o-link-source\s*:
                | -o-replace\s*:!imx', $value ) ) {
            return true;
        }

        if ( preg_match_all(
                "!(\s*(url|image|image-set)\s*\(\s*[\"']?\s*[^#]+.*?\))!sim",
                $value,
                $matches
            ) !== 0
        ) {
            # TODO: redo this in one regex. Until then, url("#whatever") matches the first
            foreach ( $matches[1] as $match ) {
                if ( !preg_match( "!\s*(url|image|image-set)\s*\(\s*(#|'#|\"#)!im", $match ) ) {
                    return true;
                }
            }
        }

        if ( preg_match( '/[\000-\010\013\016-\037\177]/', $value ) ) {
            return true;
        }

        return false;
    }

    private static function splitXmlNamespace( $element ) {
        // 'http://www.w3.org/2000/svg:script' -> [ 'http://www.w3.org/2000/svg', 'script' ]
        $parts = explode( ':', strtolower( $element ) );
        $name = array_pop( $parts );
        $ns = implode( ':', $parts );

        return [ $ns, $name ];
    }

    private function stripXmlNamespace( $name ) {
        // 'http://www.w3.org/2000/svg:script' -> 'script'
        $parts = explode( ':', strtolower( $name ) );

        return array_pop( $parts );
    }

    public static function detectVirus( $file ) {
        global $wgAntivirus, $wgAntivirusSetup, $wgAntivirusRequired, $wgOut;

        if ( !$wgAntivirus ) {
            wfDebug( __METHOD__ . ": virus scanner disabled\n" );

            return null;
        }

        if ( !$wgAntivirusSetup[$wgAntivirus] ) {
            wfDebug( __METHOD__ . ": unknown virus scanner: $wgAntivirus\n" );
            $wgOut->wrapWikiMsg( "<div class=\"error\">\n$1\n</div>",
                [ 'virus-badscanner', $wgAntivirus ] );

            return wfMessage( 'virus-unknownscanner' )->text() . " $wgAntivirus";
        }

        # look up scanner configuration
        $command = $wgAntivirusSetup[$wgAntivirus]['command'];
        $exitCodeMap = $wgAntivirusSetup[$wgAntivirus]['codemap'];
        $msgPattern = isset( $wgAntivirusSetup[$wgAntivirus]['messagepattern'] ) ?
            $wgAntivirusSetup[$wgAntivirus]['messagepattern'] : null;

        if ( strpos( $command, "%f" ) === false ) {
            # simple pattern: append file to scan
            $command .= " " . wfEscapeShellArg( $file );
        } else {
            # complex pattern: replace "%f" with file to scan
            $command = str_replace( "%f", wfEscapeShellArg( $file ), $command );
        }

        wfDebug( __METHOD__ . ": running virus scan: $command \n" );

        # execute virus scanner
        $exitCode = false;

        # NOTE: there's a 50 line workaround to make stderr redirection work on windows, too.
        #      that does not seem to be worth the pain.
        #      Ask me (Duesentrieb) about it if it's ever needed.
        $output = wfShellExecWithStderr( $command, $exitCode );

        # map exit code to AV_xxx constants.
        $mappedCode = $exitCode;
        if ( $exitCodeMap ) {
            if ( isset( $exitCodeMap[$exitCode] ) ) {
                $mappedCode = $exitCodeMap[$exitCode];
            } elseif ( isset( $exitCodeMap["*"] ) ) {
                $mappedCode = $exitCodeMap["*"];
            }
        }

        /* NB: AV_NO_VIRUS is 0 but AV_SCAN_FAILED is false,
         * so we need the strict equalities === and thus can't use a switch here
         */
        if ( $mappedCode === AV_SCAN_FAILED ) {
            # scan failed (code was mapped to false by $exitCodeMap)
            wfDebug( __METHOD__ . ": failed to scan $file (code $exitCode).\n" );

            $output = $wgAntivirusRequired
                ? wfMessage( 'virus-scanfailed', [ $exitCode ] )->text()
                : null;
        } elseif ( $mappedCode === AV_SCAN_ABORTED ) {
            # scan failed because filetype is unknown (probably imune)
            wfDebug( __METHOD__ . ": unsupported file type $file (code $exitCode).\n" );
            $output = null;
        } elseif ( $mappedCode === AV_NO_VIRUS ) {
            # no virus found
            wfDebug( __METHOD__ . ": file passed virus scan.\n" );
            $output = false;
        } else {
            $output = trim( $output );

            if ( !$output ) {
                $output = true; # if there's no output, return true
            } elseif ( $msgPattern ) {
                $groups = [];
                if ( preg_match( $msgPattern, $output, $groups ) ) {
                    if ( $groups[1] ) {
                        $output = $groups[1];
                    }
                }
            }

            wfDebug( __METHOD__ . ": FOUND VIRUS! scanner feedback: $output \n" );
        }

        return $output;
    }

    private function checkOverwrite( $user ) {
        // First check whether the local file can be overwritten
        $file = $this->getLocalFile();
        $file->load( File::READ_LATEST );
        if ( $file->exists() ) {
            if ( !self::userCanReUpload( $user, $file ) ) {
                return [ 'fileexists-forbidden', $file->getName() ];
            } else {
                return true;
            }
        }

        /* Check shared conflicts: if the local file does not exist, but
         * wfFindFile finds a file, it exists in a shared repository.
         */
        $file = wfFindFile( $this->getTitle(), [ 'latest' => true ] );
        if ( $file && !$user->isAllowed( 'reupload-shared' ) ) {
            return [ 'fileexists-shared-forbidden', $file->getName() ];
        }

        return true;
    }

    public static function userCanReUpload( User $user, File $img ) {
        if ( $user->isAllowed( 'reupload' ) ) {
            return true; // non-conditional
        } elseif ( !$user->isAllowed( 'reupload-own' ) ) {
            return false;
        }

        if ( !( $img instanceof LocalFile ) ) {
            return false;
        }

        $img->load();

        return $user->getId() == $img->getUser( 'id' );
    }

    public static function getExistsWarning( $file ) {
        if ( $file->exists() ) {
            return [ 'warning' => 'exists', 'file' => $file ];
        }

        if ( $file->getTitle()->getArticleID() ) {
            return [ 'warning' => 'page-exists', 'file' => $file ];
        }

        if ( strpos( $file->getName(), '.' ) == false ) {
            $partname = $file->getName();
            $extension = '';
        } else {
            $n = strrpos( $file->getName(), '.' );
            $extension = substr( $file->getName(), $n + 1 );
            $partname = substr( $file->getName(), 0, $n );
        }
        $normalizedExtension = File::normalizeExtension( $extension );

        if ( $normalizedExtension != $extension ) {
            // We're not using the normalized form of the extension.
            // Normal form is lowercase, using most common of alternate
            // extensions (eg 'jpg' rather than 'JPEG').

            // Check for another file using the normalized form...
            $nt_lc = Title::makeTitle( NS_FILE, "{$partname}.{$normalizedExtension}" );
            $file_lc = wfLocalFile( $nt_lc );

            if ( $file_lc->exists() ) {
                return [
                    'warning' => 'exists-normalized',
                    'file' => $file,
                    'normalizedFile' => $file_lc
                ];
            }
        }

        // Check for files with the same name but a different extension
        $similarFiles = RepoGroup::singleton()->getLocalRepo()->findFilesByPrefix(
            "{$partname}.", 1 );
        if ( count( $similarFiles ) ) {
            return [
                'warning' => 'exists-normalized',
                'file' => $file,
                'normalizedFile' => $similarFiles[0],
            ];
        }

        if ( self::isThumbName( $file->getName() ) ) {
            # Check for filenames like 50px- or 180px-, these are mostly thumbnails
            $nt_thb = Title::newFromText(
                substr( $partname, strpos( $partname, '-' ) + 1 ) . '.' . $extension,
                NS_FILE
            );
            $file_thb = wfLocalFile( $nt_thb );
            if ( $file_thb->exists() ) {
                return [
                    'warning' => 'thumb',
                    'file' => $file,
                    'thumbFile' => $file_thb
                ];
            } else {
                // File does not exist, but we just don't like the name
                return [
                    'warning' => 'thumb-name',
                    'file' => $file,
                    'thumbFile' => $file_thb
                ];
            }
        }

        foreach ( self::getFilenamePrefixBlacklist() as $prefix ) {
            if ( substr( $partname, 0, strlen( $prefix ) ) == $prefix ) {
                return [
                    'warning' => 'bad-prefix',
                    'file' => $file,
                    'prefix' => $prefix
                ];
            }
        }

        return false;
    }

    public static function isThumbName( $filename ) {
        $n = strrpos( $filename, '.' );
        $partname = $n ? substr( $filename, 0, $n ) : $filename;

        return (
            substr( $partname, 3, 3 ) == 'px-' ||
            substr( $partname, 2, 3 ) == 'px-'
        ) &&
        preg_match( "/[0-9]{2}/", substr( $partname, 0, 2 ) );
    }

    public static function getFilenamePrefixBlacklist() {
        $blacklist = [];
        $message = wfMessage( 'filename-prefix-blacklist' )->inContentLanguage();
        if ( !$message->isDisabled() ) {
            $lines = explode( "\n", $message->plain() );
            foreach ( $lines as $line ) {
                // Remove comment lines
                $comment = substr( trim( $line ), 0, 1 );
                if ( $comment == '#' || $comment == '' ) {
                    continue;
                }
                // Remove additional comments after a prefix
                $comment = strpos( $line, '#' );
                if ( $comment > 0 ) {
                    $line = substr( $line, 0, $comment - 1 );
                }
                $blacklist[] = trim( $line );
            }
        }

        return $blacklist;
    }

    public function getImageInfo( $result ) {
        $localFile = $this->getLocalFile();
        $stashFile = $this->getStashFile();
        // Calling a different API module depending on whether the file was stashed is less than optimal.
        // In fact, calling API modules here at all is less than optimal. Maybe it should be refactored.
        if ( $stashFile ) {
            $imParam = ApiQueryStashImageInfo::getPropertyNames();
            $info = ApiQueryStashImageInfo::getInfo( $stashFile, array_flip( $imParam ), $result );
        } else {
            $imParam = ApiQueryImageInfo::getPropertyNames();
            $info = ApiQueryImageInfo::getInfo( $localFile, array_flip( $imParam ), $result );
        }

        return $info;
    }

    public function convertVerifyErrorToStatus( $error ) {
        $code = $error['status'];
        unset( $code['status'] );

        return Status::newFatal( $this->getVerificationErrorCode( $code ), $error );
    }

    public static function getMaxUploadSize( $forType = null ) {
        global $wgMaxUploadSize;

        if ( is_array( $wgMaxUploadSize ) ) {
            if ( !is_null( $forType ) && isset( $wgMaxUploadSize[$forType] ) ) {
                return $wgMaxUploadSize[$forType];
            } else {
                return $wgMaxUploadSize['*'];
            }
        } else {
            return intval( $wgMaxUploadSize );
        }
    }

    public static function getMaxPhpUploadSize() {
        $phpMaxFileSize = wfShorthandToInteger(
            ini_get( 'upload_max_filesize' ) ?: ini_get( 'hhvm.server.upload.upload_max_file_size' ),
            PHP_INT_MAX
        );
        $phpMaxPostSize = wfShorthandToInteger(
            ini_get( 'post_max_size' ) ?: ini_get( 'hhvm.server.max_post_size' ),
            PHP_INT_MAX
        ) ?: PHP_INT_MAX;
        return min( $phpMaxFileSize, $phpMaxPostSize );
    }

    public static function getSessionStatus( User $user, $statusKey ) {
        $key = wfMemcKey( 'uploadstatus', $user->getId() ?: md5( $user->getName() ), $statusKey );

        return ObjectCache::getMainStashInstance()->get( $key );
    }

    public static function setSessionStatus( User $user, $statusKey, $value ) {
        $key = wfMemcKey( 'uploadstatus', $user->getId() ?: md5( $user->getName() ), $statusKey );

        $cache = ObjectCache::getMainStashInstance();
        if ( $value === false ) {
            $cache->delete( $key );
        } else {
            $cache->set( $key, $value, $cache::TTL_DAY );
        }
    }
}