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[mediawiki.git] / includes / libs / mime / MimeAnalyzer.php

<?php
/**
 * 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
 */

namespace Wikimedia\Mime;

use Psr\Log\LoggerAwareInterface;
use Psr\Log\LoggerInterface;
use Psr\Log\NullLogger;
use UnexpectedValueException;
use Wikimedia\AtEase\AtEase;
use ZipDirectoryReader;

/**
 * @defgroup Mime Mime
 *
 * @ingroup Media
 */

/**
 * Detect MIME types of a file by mapping file extensions or parsing file contents.
 *
 * @since 1.28
 * @ingroup Mime
 */
class MimeAnalyzer implements LoggerAwareInterface {
        /** @var string */
        protected $typeFile;
        /** @var string */
        protected $infoFile;
        /** @var string */
        protected $xmlTypes;
        /** @var callable */
        protected $initCallback;
        /** @var callable */
        protected $detectCallback;
        /** @var callable */
        protected $guessCallback;
        /** @var callable */
        protected $extCallback;
        /** @var array Mapping of media types to arrays of MIME types */
        protected $mediaTypes = null;
        /** @var array Map of MIME type aliases */
        protected $mimeTypeAliases = null;
        /** @var array<string,string[]> Map of MIME types to file extensions */
        protected $mimeToExts = [];
        /** @var array<string,string[]> Map of file extensions to MIME types */
        protected $extToMimes = [];

        /** @var array Map of file extensions types to MIME types (as a space separated list) */
        public $mExtToMime = []; // legacy name; field accessed by hooks

        /** @var string Extra MIME types, set for example by media handling extensions */
        private $extraTypes = '';
        /** @var string Extra MIME info, set for example by media handling extensions */
        private $extraInfo = '';

        /** @var LoggerInterface */
        private $logger;

        /** @var string Use the full, built-in MIME mapping rather than load from a file */
        public const USE_INTERNAL = 'internal';

        /**
         * @param array $params Configuration map, includes:
         *   - typeFile: path to file with the list of known MIME types
         *   - infoFile: path to file with the MIME type info
         *   - xmlTypes: map of root element names to XML MIME types
         *   - initCallback: initialization callback that is passed this object [optional]
         *   - detectCallback: alternative to finfo that returns the mime type for a file.
         *      For example, the callback can return the output of "file -bi". [optional]
         *   - guessCallback: callback to improve the guessed MIME type using the file data.
         *      This is intended for fixing mistakes in fileinfo or "detectCallback". [optional]
         *   - extCallback: callback to improve the guessed MIME type using the extension. [optional]
         *   - logger: PSR-3 logger [optional]
         * @note Constructing these instances is expensive due to file reads.
         *  A service or singleton pattern should be used to avoid creating instances again and again.
         */
        public function __construct( array $params ) {
                $this->typeFile = $params['typeFile'];
                $this->infoFile = $params['infoFile'];
                $this->xmlTypes = $params['xmlTypes'];
                $this->initCallback = $params['initCallback'] ?? null;
                $this->detectCallback = $params['detectCallback'] ?? null;
                $this->guessCallback = $params['guessCallback'] ?? null;
                $this->extCallback = $params['extCallback'] ?? null;
                $this->logger = $params['logger'] ?? new NullLogger();

                $this->loadFiles();
        }

        protected function loadFiles(): void {
                # Allow media handling extensions adding MIME-types and MIME-info
                if ( $this->initCallback ) {
                        call_user_func( $this->initCallback, $this );
                }

                $rawTypes = $this->extraTypes;
                if ( $this->typeFile === self::USE_INTERNAL ) {
                        $this->mimeToExts = MimeMap::MIME_EXTENSIONS;
                } else {
                        $this->mimeToExts = MimeMapMinimal::MIME_EXTENSIONS;
                        if ( $this->typeFile ) {
                                $rawTypes = file_get_contents( $this->typeFile ) . "\n" . $this->extraTypes;
                        }
                }
                if ( $rawTypes ) {
                        $this->parseMimeTypes( $rawTypes );
                }

                // Build the reverse mapping (extension => MIME type).
                foreach ( $this->mimeToExts as $mime => $exts ) {
                        foreach ( $exts as $ext ) {
                                $this->extToMimes[$ext][] = $mime;
                        }
                }

                // Migrate items from the legacy $this->mExtToMime field.
                // TODO: Remove this when mExtToMime is finally removed.
                foreach ( $this->mExtToMime as $ext => $mimes ) {
                        foreach ( explode( ' ', $mimes ) as $mime ) {
                                $this->extToMimes[$ext][] = $mime;
                        }
                }

                $rawInfo = $this->extraInfo;
                if ( $this->infoFile === self::USE_INTERNAL ) {
                        $this->mimeTypeAliases = MimeMap::MIME_TYPE_ALIASES;
                        $this->mediaTypes = MimeMap::MEDIA_TYPES;
                } else {
                        $this->mimeTypeAliases = MimeMapMinimal::MIME_TYPE_ALIASES;
                        $this->mediaTypes = MimeMapMinimal::MEDIA_TYPES;
                        if ( $this->infoFile ) {
                                $rawInfo = file_get_contents( $this->infoFile ) . "\n" . $this->extraInfo;
                        }
                }
                if ( $rawInfo ) {
                        $this->parseMimeInfo( $rawInfo );
                }
        }

        protected function parseMimeTypes( string $rawMimeTypes ): void {
                $rawMimeTypes = str_replace( [ "\r\n", "\n\r", "\n\n", "\r\r", "\r" ], "\n", $rawMimeTypes );
                $rawMimeTypes = str_replace( "\t", " ", $rawMimeTypes );

                $lines = explode( "\n", $rawMimeTypes );
                foreach ( $lines as $s ) {
                        $s = trim( $s );
                        if ( $s === '' || str_starts_with( $s, '#' ) ) {
                                continue;
                        }

                        $s = strtolower( $s );
                        $i = strpos( $s, ' ' );

                        if ( $i === false ) {
                                continue;
                        }

                        $ext = trim( substr( $s, $i + 1 ) );

                        if ( !$ext ) {
                                continue;
                        }

                        $tokens = preg_split( '/\s+/', $s, -1, PREG_SPLIT_NO_EMPTY );
                        if ( count( $tokens ) > 1 ) {
                                $mime = array_shift( $tokens );
                                $this->mimeToExts[$mime] = array_values( array_unique(
                                        array_merge( $this->mimeToExts[$mime] ?? [], $tokens ) ) );
                        }
                }
        }

        protected function parseMimeInfo( string $rawMimeInfo ): void {
                $rawMimeInfo = str_replace( [ "\r\n", "\n\r", "\n\n", "\r\r", "\r" ], "\n", $rawMimeInfo );
                $rawMimeInfo = str_replace( "\t", " ", $rawMimeInfo );

                $lines = explode( "\n", $rawMimeInfo );
                foreach ( $lines as $s ) {
                        $s = trim( $s );
                        if ( $s === '' || str_starts_with( $s, '#' ) ) {
                                continue;
                        }

                        $s = strtolower( $s );
                        $i = strpos( $s, ' ' );

                        if ( $i === false ) {
                                continue;
                        }

                        # print "processing MIME INFO line $s<br>";

                        $match = [];
                        if ( preg_match( '!\[\s*(\w+)\s*\]!', $s, $match ) ) {
                                $s = preg_replace( '!\[\s*(\w+)\s*\]!', '', $s );
                                $mtype = trim( strtoupper( $match[1] ) );
                        } else {
                                $mtype = MEDIATYPE_UNKNOWN;
                        }

                        $m = preg_split( '/\s+/', $s, -1, PREG_SPLIT_NO_EMPTY );

                        if ( !isset( $this->mediaTypes[$mtype] ) ) {
                                $this->mediaTypes[$mtype] = [];
                        }

                        foreach ( $m as $mime ) {
                                $mime = trim( $mime );
                                if ( !$mime ) {
                                        continue;
                                }

                                $this->mediaTypes[$mtype][] = $mime;
                        }

                        if ( count( $m ) > 1 ) {
                                $main = $m[0];
                                $mCount = count( $m );
                                for ( $i = 1; $i < $mCount; $i += 1 ) {
                                        $mime = $m[$i];
                                        $this->mimeTypeAliases[$mime] = $main;
                                }
                        }
                }
        }

        public function setLogger( LoggerInterface $logger ) {
                $this->logger = $logger;
        }

        /**
         * Adds to the list mapping MIME to file extensions.
         *
         * As an extension author, you are encouraged to submit patches to
         * MediaWiki's core to add new MIME types to MimeMap.php.
         *
         * @param string $types
         */
        public function addExtraTypes( string $types ): void {
                $this->extraTypes .= "\n" . $types;
        }

        /**
         * Adds to the list mapping MIME to media type.
         *
         * As an extension author, you are encouraged to submit patches to
         * MediaWiki's core to add new MIME info to MimeMap.php.
         *
         * @param string $info
         */
        public function addExtraInfo( string $info ): void {
                $this->extraInfo .= "\n" . $info;
        }

        /**
         * Returns a list of file extensions for a given MIME type as a space
         * separated string or null if the MIME type was unrecognized. Resolves
         * MIME type aliases.
         *
         * @deprecated since 1.35 Use getExtensionsFromMimeType() instead.
         * @param string $mime
         * @return string|null
         */
        public function getExtensionsForType( $mime ) {
                $exts = $this->getExtensionsFromMimeType( $mime );
                return $exts ? implode( ' ', $exts ) : null;
        }

        /**
         * Returns an array of file extensions associated with a given MIME type.
         * The returned array is empty if the MIME type was unrecognized. Resolves
         * MIME type aliases.
         *
         * @since 1.35
         * @param string $mime
         * @return string[]
         */
        public function getExtensionsFromMimeType( string $mime ): array {
                $mime = strtolower( $mime );
                if ( !isset( $this->mimeToExts[$mime] ) && isset( $this->mimeTypeAliases[$mime] ) ) {
                        $mime = $this->mimeTypeAliases[$mime];
                }
                return $this->mimeToExts[$mime] ?? [];
        }

        /**
         * Returns an array of MIME types associated with a given file extension.
         * The returned array is empty if the file extension is not associated with
         * any MIME types.
         *
         * @since 1.35
         * @param string $ext
         * @return string[]
         */
        public function getMimeTypesFromExtension( string $ext ): array {
                $ext = strtolower( $ext );
                return $this->extToMimes[$ext] ?? [];
        }

        /**
         * Returns a single MIME type for a given file extension or null if unknown.
         * This is always the first type from the list returned by getMimeTypesFromExtension($ext).
         *
         * @since 1.35
         * @param string $ext
         * @return string|null
         */
        public function getMimeTypeFromExtensionOrNull( string $ext ): ?string {
                $types = $this->getMimeTypesFromExtension( $ext );
                return $types[0] ?? null;
        }

        /**
         * Returns a single file extension for a given MIME type or null if unknown.
         * This is always the first type from the list returned by getExtensionsFromMimeType($mime).
         *
         * @deprecated since 1.35 Use getMimeTypeFromExtensionOrNull() instead.
         * @param string $ext
         * @return string|null
         */
        public function guessTypesForExtension( $ext ) {
                return $this->getMimeTypeFromExtensionOrNull( $ext );
        }

        /**
         * Returns a list of MIME types for a given file extension as a space
         * separated string or null if the extension was unrecognized.
         *
         * @deprecated since 1.35 Use getMimeTypesFromExtension() instead.
         * @param string $ext
         * @return string|null
         */
        public function getTypesForExtension( $ext ) {
                $types = $this->getMimeTypesFromExtension( $ext );
                return $types ? implode( ' ', $types ) : null;
        }

        /**
         * Returns a single file extension for a given MIME type or null if unknown.
         * This is always the first type from the list returned by getExtensionsFromMimeType($mime).
         *
         * @since 1.35
         * @param string $mime
         * @return string|null
         */
        public function getExtensionFromMimeTypeOrNull( string $mime ): ?string {
                $exts = $this->getExtensionsFromMimeType( $mime );
                return $exts[0] ?? null;
        }

        /**
         * Tests if the extension matches the given MIME type. Returns true if a
         * match was found, null if the MIME type is unknown, and false if the
         * MIME type is known but no matches where found.
         *
         * @param string $extension
         * @param string $mime
         * @return bool|null
         */
        public function isMatchingExtension( string $extension, string $mime ): ?bool {
                $exts = $this->getExtensionsFromMimeType( $mime );

                if ( !$exts ) {
                        return null; // Unknown MIME type
                }

                return in_array( strtolower( $extension ), $exts );
        }

        /**
         * Returns true if the MIME type is known to represent an image format
         * supported by the PHP GD library.
         *
         * @deprecated since 1.40
         * @param string $mime
         * @return bool
         */
        public function isPHPImageType( string $mime ): bool {
                wfDeprecated( __METHOD__, '1.40' );
                // As defined by imagegetsize and image_type_to_mime
                static $types = [
                        'image/gif', 'image/jpeg', 'image/png',
                        'image/x-bmp', 'image/xbm', 'image/tiff',
                        'image/jp2', 'image/jpeg2000', 'image/iff',
                        'image/xbm', 'image/x-xbitmap',
                        'image/vnd.wap.wbmp', 'image/vnd.xiff',
                        'image/x-photoshop',
                        'application/x-shockwave-flash',
                ];

                return in_array( $mime, $types );
        }

        /**
         * Returns true if the extension represents a type which can
         * be reliably detected from its content. Use this to determine
         * whether strict content checks should be applied to reject
         * invalid uploads; if we can't identify the type we won't
         * be able to say if it's invalid.
         *
         * @todo Be more accurate when using fancy MIME detector plugins;
         *       right now this is the bare minimum getimagesize() list.
         * @param string $extension
         * @return bool
         */
        public function isRecognizableExtension( string $extension ): bool {
                static $types = [
                        // Types recognized by getimagesize()
                        'gif', 'jpeg', 'jpg', 'png', 'swf', 'psd',
                        'bmp', 'tiff', 'tif', 'jpc', 'jp2',
                        'jpx', 'jb2', 'swc', 'iff', 'wbmp',
                        'xbm',

                        // Formats we recognize magic numbers for
                        'djvu', 'ogx', 'ogg', 'ogv', 'oga', 'spx', 'opus',
                        'mid', 'pdf', 'wmf', 'xcf', 'webm', 'mkv', 'mka',
                        'webp', 'mp3',

                        // XML formats we sure hope we recognize reliably
                        'svg',

                        // 3D formats
                        'stl',
                ];
                return in_array( strtolower( $extension ), $types );
        }

        /**
         * Improves a MIME type using the file extension. Some file formats are very generic,
         * so their MIME type is not very meaningful. A more useful MIME type can be derived
         * by looking at the file extension. Typically, this method would be called on the
         * result of guessMimeType().
         *
         * XXX: Null-returning behavior is probably an accident and definitely confusing (T253483).
         *
         * @param string $mime The MIME type, typically guessed from a file's content.
         * @param string $ext The file extension, as taken from the file name
         * @return string|null The improved MIME type, or null if the MIME type is
         *   unknown/unknown and the extension is not recognized.
         */
        public function improveTypeFromExtension( string $mime, string $ext ): ?string {
                if ( $mime === 'unknown/unknown' ) {
                        if ( $this->isRecognizableExtension( $ext ) ) {
                                $this->logger->info( __METHOD__ . ': refusing to guess mime type for .' .
                                        "$ext file, we should have recognized it" );
                        } else {
                                // Not something we can detect, so simply
                                // trust the file extension
                                $mime = $this->getMimeTypeFromExtensionOrNull( $ext );
                        }
                } elseif ( $mime === 'application/x-opc+zip'
                        || $mime === 'application/vnd.oasis.opendocument'
                ) {
                        if ( $this->isMatchingExtension( $ext, $mime ) ) {
                                // A known file extension for an OPC/ODF file,
                                // find the proper MIME type for that file extension
                                $mime = $this->getMimeTypeFromExtensionOrNull( $ext );
                        } else {
                                $this->logger->info( __METHOD__ .
                                        ": refusing to guess better type for $mime file, " .
                                        ".$ext is not a known OPC/ODF extension." );
                                $mime = 'application/zip';
                        }
                } elseif ( $mime === 'text/plain' && $this->findMediaType( ".$ext" ) === MEDIATYPE_TEXT ) {
                        // Textual types are sometimes not recognized properly.
                        // If detected as text/plain, and has an extension which is textual
                        // improve to the extension's type. For example, csv and json are often
                        // misdetected as text/plain.
                        $mime = $this->getMimeTypeFromExtensionOrNull( $ext );
                }

                # Media handling extensions can improve the MIME detected
                $callback = $this->extCallback;
                if ( $callback ) {
                        $callback( $this, $ext, $mime /* by reference */ );
                }

                if ( $mime !== null && isset( $this->mimeTypeAliases[$mime] ) ) {
                        $mime = $this->mimeTypeAliases[$mime];
                }

                $this->logger->info( __METHOD__ . ": improved mime type for .$ext: $mime" );
                return $mime;
        }

        /**
         * MIME type detection. This uses detectMimeType to detect the MIME type
         * of the file, but applies additional checks to determine some well known
         * file formats that may be missed or misinterpreted by the default MIME
         * detection (namely XML based formats like XHTML or SVG, as well as ZIP
         * based formats like OPC/ODF files).
         *
         * @param string $file The file to check
         * @param string|bool $ext The file extension, or true (default) to extract
         * it from the filename. Set it to false to ignore the extension. DEPRECATED!
         * Set to false, use improveTypeFromExtension($mime, $ext) later to improve MIME type.
         * @return string The MIME type of $file
         */
        public function guessMimeType( string $file, $ext = true ): string {
                if ( $ext ) { // TODO: make $ext default to false. Or better, remove it.
                        $this->logger->info( __METHOD__ .
                                ": WARNING: use of the \$ext parameter is deprecated. " .
                                "Use improveTypeFromExtension(\$mime, \$ext) instead." );
                }

                $mime = $this->doGuessMimeType( $file );

                if ( !$mime ) {
                        $this->logger->info( __METHOD__ .
                                ": internal type detection failed for $file (.$ext)..." );
                        $mime = $this->detectMimeType( $file, $ext );
                }

                if ( isset( $this->mimeTypeAliases[$mime] ) ) {
                        $mime = $this->mimeTypeAliases[$mime];
                }

                $this->logger->info( __METHOD__ . ": guessed mime type of $file: $mime" );
                return $mime;
        }

        /**
         * Guess the MIME type from the file contents.
         *
         * @param string $file
         * @return bool|string
         * @throws UnexpectedValueException
         */
        private function doGuessMimeType( string $file ) {
                // Read a chunk of the file
                AtEase::suppressWarnings();
                $f = fopen( $file, 'rb' );
                AtEase::restoreWarnings();

                if ( !$f ) {
                        return 'unknown/unknown';
                }

                $fsize = filesize( $file );
                if ( $fsize === false ) {
                        return 'unknown/unknown';
                }

                $head = fread( $f, 1024 );
                $head16k = $head . fread( $f, 16384 - 1024 ); // some WebM files have big headers
                $tailLength = min( 65558, $fsize ); // 65558 = maximum size of a zip EOCDR
                if ( fseek( $f, -1 * $tailLength, SEEK_END ) === -1 ) {
                        throw new UnexpectedValueException(
                                "Seeking $tailLength bytes from EOF failed in " . __METHOD__ );
                }
                $tail = $tailLength ? fread( $f, $tailLength ) : '';

                $this->logger->info( __METHOD__ .
                        ": analyzing head and tail of $file for magic numbers." );

                // Hardcode a few magic number checks...
                $headers = [
                        // Multimedia...
                        'MThd'             => 'audio/midi',
                        'OggS'             => 'application/ogg',
                        'ID3'              => 'audio/mpeg',
                        "\xff\xfb"         => 'audio/mpeg', // MPEG-1 layer 3
                        "\xff\xf3"         => 'audio/mpeg', // MPEG-2 layer 3 (lower sample rates)
                        "\xff\xe3"         => 'audio/mpeg', // MPEG-2.5 layer 3 (very low sample rates)

                        // Image formats...
                        // Note that WMF may have a bare header, no magic number.
                        "\x01\x00\x09\x00" => 'application/x-msmetafile', // Possibly prone to false positives?
                        "\xd7\xcd\xc6\x9a" => 'application/x-msmetafile',
                        '%PDF'             => 'application/pdf',
                        'gimp xcf'         => 'image/x-xcf',

                        // Some forbidden fruit...
                        'MZ'               => 'application/octet-stream', // DOS/Windows executable
                        "\xca\xfe\xba\xbe" => 'application/octet-stream', // Mach-O binary
                        "\x7fELF"          => 'application/octet-stream', // ELF binary
                ];

                foreach ( $headers as $magic => $candidate ) {
                        if ( str_starts_with( $head, $magic ) ) {
                                $this->logger->info( __METHOD__ .
                                        ": magic header in $file recognized as $candidate" );
                                return $candidate;
                        }
                }

                /* Look for WebM and Matroska files */
                if ( str_starts_with( $head16k, pack( "C4", 0x1a, 0x45, 0xdf, 0xa3 ) ) ) {
                        $doctype = strpos( $head16k, "\x42\x82" );
                        if ( $doctype ) {
                                // Next byte is datasize, then data (sizes larger than 1 byte are stupid muxers)
                                $data = substr( $head16k, $doctype + 3, 8 );
                                if ( str_starts_with( $data, "matroska" ) ) {
                                        $this->logger->info( __METHOD__ . ": recognized file as video/x-matroska" );
                                        return "video/x-matroska";
                                }

                                if ( str_starts_with( $data, "webm" ) ) {
                                        // XXX HACK look for a video track, if we don't find it, this is an audio file
                                        // This detection is very naive and doesn't parse the actual fields
                                        // 0x86 byte indicates start of codecname field
                                        // next byte is a variable length integer (vint) for the size of the value following it
                                        // 8 (first bit is 1) indicates the smallest size vint, a single byte
                                        // (unlikely we see larger vints here)
                                        // 5 indicates a length of 5 ( V_VP8 or V_VP9 or V_AV1 )
                                        // Sometimes we see 0x86 instead of 0x85 because a
                                        // non-conforming muxer wrote a null terminated string
                                        $videotrack = str_contains( $head16k, "\x86\x85V_VP8" ) ||
                                                str_contains( $head16k, "\x86\x85V_VP9" ) ||
                                                str_contains( $head16k, "\x86\x85V_AV1" ) ||
                                                str_contains( $head16k, "\x86\x86V_VP8\x0" ) ||
                                                str_contains( $head16k, "\x86\x86V_VP9\x0" ) ||
                                                str_contains( $head16k, "\x86\x86V_AV1\x0" );

                                        if ( $videotrack ) {
                                                // There is a video track, so this is a video file.
                                                $this->logger->info( __METHOD__ . ": recognized file as video/webm" );
                                                return "video/webm";
                                        }

                                        $this->logger->info( __METHOD__ . ": recognized file as audio/webm" );
                                        return "audio/webm";
                                }
                        }
                        $this->logger->info( __METHOD__ . ": unknown EBML file" );
                        return "unknown/unknown";
                }

                /* Look for WebP */
                if ( str_starts_with( $head, "RIFF" ) && substr( $head, 8, 7 ) === "WEBPVP8" ) {
                        $this->logger->info( __METHOD__ . ": recognized file as image/webp" );
                        return "image/webp";
                }

                /* Look for JPEG2000 */
                if ( str_starts_with( $head, "\x00\x00\x00\x0cjP\x20\x20\x0d\x0a\x87\x0a" ) ) {
                        $this->logger->info( __METHOD__ . ": recognized as JPEG2000" );
                        // we skip 4 bytes
                        if ( substr( $head, 16, 8 ) === "ftypjp2 " ) {
                                $this->logger->info( __METHOD__ . ": recognized file as image/jp2" );
                                return 'image/jp2';
                        } elseif ( substr( $head, 16, 8 ) === "ftypjpx " ) {
                                $this->logger->info( __METHOD__ . ": recognized file as image/jpx" );
                                return 'image/jpx';
                        }
                }

                /* Look for MS Compound Binary (OLE) files */
                if ( str_starts_with( $head, "\xd0\xcf\x11\xe0\xa1\xb1\x1a\xe1" ) ) {
                        $this->logger->info( __METHOD__ . ': recognized MS CFB (OLE) file' );
                        return $this->detectMicrosoftBinaryType( $f );
                }

                /**
                 * Look for PHP.  Check for this before HTML/XML...  Warning: this is a
                 * heuristic, and won't match a file with a lot of non-PHP before.  It
                 * will also match text files which could be PHP. :)
                 *
                 * @todo FIXME: For this reason, the check is probably useless -- an attacker
                 * could almost certainly just pad the file with a lot of nonsense to
                 * circumvent the check in any case where it would be a security
                 * problem.  On the other hand, it causes harmful false positives (bug
                 * 16583).  The heuristic has been cut down to exclude three-character
                 * strings like "<? ", but should it be axed completely?
                 */
                if ( ( strpos( $head, '<?php' ) !== false ) ||
                        ( strpos( $head, "<\x00?\x00p\x00h\x00p" ) !== false ) ||
                        ( strpos( $head, "<\x00?\x00 " ) !== false ) ||
                        ( strpos( $head, "<\x00?\x00\n" ) !== false ) ||
                        ( strpos( $head, "<\x00?\x00\t" ) !== false ) ||
                        ( strpos( $head, "<\x00?\x00=" ) !== false )
                ) {
                        $this->logger->info( __METHOD__ . ": recognized $file as application/x-php" );
                        return 'application/x-php';
                }

                /**
                 * look for XML formats (XHTML and SVG)
                 */
                AtEase::suppressWarnings();
                $xml = new XmlTypeCheck( $file );
                AtEase::restoreWarnings();
                if ( $xml->wellFormed ) {
                        $xmlTypes = $this->xmlTypes;
                        // @phan-suppress-next-line PhanTypeMismatchDimFetch False positive
                        return $xmlTypes[$xml->getRootElement()] ?? 'application/xml';
                }

                /**
                 * look for shell scripts
                 */
                $script_type = null;

                # detect by shebang
                if ( str_starts_with( $head, "#!" ) ) {
                        $script_type = "ASCII";
                } elseif ( str_starts_with( $head, "\xef\xbb\xbf#!" ) ) {
                        $script_type = "UTF-8";
                } elseif ( str_starts_with( $head, "\xfe\xff\x00#\x00!" ) ) {
                        $script_type = "UTF-16BE";
                } elseif ( str_starts_with( $head, "\xff\xfe#\x00!" ) ) {
                        $script_type = "UTF-16LE";
                }

                if ( $script_type ) {
                        if ( $script_type !== "UTF-8" && $script_type !== "ASCII" ) {
                                // Quick and dirty fold down to ASCII!
                                $pack = [ 'UTF-16BE' => 'n*', 'UTF-16LE' => 'v*' ];
                                $chars = unpack( $pack[$script_type], substr( $head, 2 ) );
                                $head = '';
                                foreach ( $chars as $codepoint ) {
                                        if ( $codepoint < 128 ) {
                                                $head .= chr( $codepoint );
                                        } else {
                                                $head .= '?';
                                        }
                                }
                        }

                        $match = [];

                        if ( preg_match( '%/?([^\s]+/)(\w+)%', $head, $match ) ) {
                                $mime = "application/x-{$match[2]}";
                                $this->logger->info( __METHOD__ . ": shell script recognized as $mime" );
                                return $mime;
                        }
                }

                // Check for ZIP variants (before getimagesize)
                $eocdrPos = strpos( $tail, "PK\x05\x06" );
                if ( $eocdrPos !== false && $eocdrPos <= strlen( $tail ) - 22 ) {
                        $this->logger->info( __METHOD__ . ": ZIP signature present in $file" );
                        // Check if it really is a ZIP file, make sure the EOCDR is at the end (T40432)
                        $commentLength = unpack( "n", substr( $tail, $eocdrPos + 20 ) )[1];
                        if ( $eocdrPos + 22 + $commentLength !== strlen( $tail ) ) {
                                $this->logger->info( __METHOD__ . ": ZIP EOCDR not at end. Not a ZIP file." );
                        } else {
                                return $this->detectZipTypeFromFile( $f );
                        }
                }

                // Check for STL (3D) files
                // @see https://en.wikipedia.org/wiki/STL_(file_format)
                if ( $fsize >= 15 &&
                        stripos( $head, 'SOLID ' ) === 0 &&
                        preg_match( '/\RENDSOLID .*$/i', $tail ) ) {
                        // ASCII STL file
                        return 'application/sla';
                } elseif ( $fsize > 84 ) {
                        // binary STL file
                        $triangles = substr( $head, 80, 4 );
                        $triangles = unpack( 'V', $triangles );
                        $triangles = reset( $triangles );
                        if ( $triangles !== false && $fsize === 84 + ( $triangles * 50 ) ) {
                                return 'application/sla';
                        }
                }

                AtEase::suppressWarnings();
                $gis = getimagesize( $file );
                AtEase::restoreWarnings();

                if ( $gis && isset( $gis['mime'] ) ) {
                        $mime = $gis['mime'];
                        $this->logger->info( __METHOD__ . ": getimagesize detected $file as $mime" );
                        return $mime;
                }

                # Media handling extensions can guess the MIME by content
                # It's intentionally here so that if core is wrong about a type (false positive),
                # people will hopefully nag and submit patches :)
                $mime = false;
                # Some strings by reference for performance - assuming well-behaved hooks
                $callback = $this->guessCallback;
                if ( $callback ) {
                        $callback( $this, $head, $tail, $file, $mime /* by reference */ );
                }

                return $mime;
        }

        /**
         * Detect application-specific file type of a given ZIP file.
         * If it can't tell, return 'application/zip'.
         *
         * @internal
         * @param resource $handle
         * @return string
         */
        public function detectZipTypeFromFile( $handle ) {
                $types = [];
                $status = ZipDirectoryReader::readHandle(
                        $handle,
                        static function ( $entry ) use ( &$types ) {
                                $name = $entry['name'];
                                $names = [ $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 ) ) {
                                        $types[] = 'application/java';
                                }

                                if ( $name === '[Content_Types].xml' ) {
                                        $types[] = 'application/x-opc+zip';
                                } elseif ( $name === 'mimetype' ) {
                                        $types[] = 'application/vnd.oasis.opendocument';
                                }
                        }
                );
                if ( !$status->isOK() ) {
                        $this->logger->info( "Error reading zip file: " . (string)$status );
                        // This could be unknown/unknown but we have some weird phpunit test cases
                        return 'application/zip';
                }
                if ( in_array( 'application/java', $types ) ) {
                        // For security, java detection takes precedence
                        return 'application/java';
                } elseif ( count( $types ) ) {
                        return $types[0];
                } else {
                        return 'application/zip';
                }
        }

        /**
         * Detect the type of a Microsoft Compound Binary a.k.a. OLE file.
         * These are old style pre-ODF files such as .doc and .xls
         *
         * @param resource $handle An opened seekable file handle
         * @return string The detected MIME type
         */
        private function detectMicrosoftBinaryType( $handle ): string {
                $info = MSCompoundFileReader::readHandle( $handle );
                if ( !$info['valid'] ) {
                        $this->logger->info( __METHOD__ . ': invalid file format' );
                        return 'unknown/unknown';
                }
                if ( !$info['mime'] ) {
                        $this->logger->info( __METHOD__ . ": unrecognised document subtype" );
                        return 'unknown/unknown';
                }
                return $info['mime'];
        }

        /**
         * Internal MIME type detection. Detection is done using the fileinfo
         * extension if it is available. It can be overridden by callback, which could
         * use an external program, for example. If detection fails and $ext is not false,
         * the MIME type is guessed from the file extension, using getMimeTypeFromExtensionOrNull.
         *
         * If the MIME type is still unknown, getimagesize is used to detect the
         * MIME type if the file is an image. If no MIME type can be determined,
         * this function returns 'unknown/unknown'.
         *
         * @param string $file The file to check
         * @param string|bool $ext The file extension, or true (default) to extract it from the filename.
         * Set it to false to ignore the extension. DEPRECATED! Set to false, use
         * improveTypeFromExtension($mime, $ext) later to improve MIME type.
         * @return string The MIME type of $file
         */
        private function detectMimeType( string $file, $ext = true ): string {
                /** @todo Make $ext default to false. Or better, remove it. */
                if ( $ext ) {
                        $this->logger->info( __METHOD__ .
                                ": WARNING: use of the \$ext parameter is deprecated. "
                                . "Use improveTypeFromExtension(\$mime, \$ext) instead." );
                }

                $callback = $this->detectCallback;
                if ( $callback ) {
                        $m = $callback( $file );
                } else {
                        $m = mime_content_type( $file );
                }

                if ( $m ) {
                        # normalize
                        $m = preg_replace( '![;, ].*$!', '', $m ); # strip charset, etc
                        $m = trim( $m );
                        $m = strtolower( $m );

                        if ( !str_contains( $m, 'unknown' ) ) {
                                $this->logger->info( __METHOD__ . ": magic mime type of $file: $m" );
                                return $m;
                        }
                }

                // If desired, look at extension as a fallback.
                if ( $ext === true ) {
                        $i = strrpos( $file, '.' );
                        $ext = strtolower( $i ? substr( $file, $i + 1 ) : '' );
                }
                if ( $ext ) {
                        if ( $this->isRecognizableExtension( $ext ) ) {
                                $this->logger->info( __METHOD__ . ": refusing to guess mime type for .$ext file, "
                                        . "we should have recognized it" );
                        } else {
                                $m = $this->getMimeTypeFromExtensionOrNull( $ext );
                                if ( $m ) {
                                        $this->logger->info( __METHOD__ . ": extension mime type of $file: $m" );
                                        return $m;
                                }
                        }
                }

                // Unknown type
                $this->logger->info( __METHOD__ . ": failed to guess mime type for $file!" );
                return 'unknown/unknown';
        }

        /**
         * Determine the media type code for a file, using its MIME type, name and
         * possibly its contents.
         *
         * This function relies on the findMediaType(), mapping extensions and MIME
         * types to media types.
         *
         * @todo analyse file if need be
         * @todo look at multiple extension, separately and together.
         *
         * @param string|null $path Full path to the image file, in case we have to look at the contents
         * (if null, only the MIME type is used to determine the media type code).
         * @param string|null $mime MIME type. If null it will be guessed using guessMimeType.
         * @return string A value to be used with the MEDIATYPE_xxx constants.
         */
        public function getMediaType( ?string $path = null, ?string $mime = null ): string {
                if ( !$mime && !$path ) {
                        return MEDIATYPE_UNKNOWN;
                }

                // If MIME type is unknown, guess it
                if ( !$mime ) {
                        // @phan-suppress-next-line PhanTypeMismatchArgumentNullable False positive
                        $mime = $this->guessMimeType( $path, false );
                }

                // Special code for ogg - detect if it's video (theora),
                // else label it as sound.
                if ( $mime == 'application/ogg' && is_string( $path ) && file_exists( $path ) ) {
                        // Read a chunk of the file
                        $f = fopen( $path, "rt" );
                        if ( !$f ) {
                                return MEDIATYPE_UNKNOWN;
                        }
                        $head = fread( $f, 256 );
                        fclose( $f );

                        $head = str_replace( 'ffmpeg2theora', '', strtolower( $head ) );

                        // This is an UGLY HACK, file should be parsed correctly
                        if ( strpos( $head, 'theora' ) !== false ) {
                                return MEDIATYPE_VIDEO;
                        } elseif ( strpos( $head, 'vorbis' ) !== false ) {
                                return MEDIATYPE_AUDIO;
                        } elseif ( strpos( $head, 'flac' ) !== false ) {
                                return MEDIATYPE_AUDIO;
                        } elseif ( strpos( $head, 'speex' ) !== false ) {
                                return MEDIATYPE_AUDIO;
                        } elseif ( strpos( $head, 'opus' ) !== false ) {
                                return MEDIATYPE_AUDIO;
                        } else {
                                return MEDIATYPE_MULTIMEDIA;
                        }
                }

                $type = null;
                // Check for entry for full MIME type
                if ( $mime ) {
                        $type = $this->findMediaType( $mime );
                        if ( $type !== MEDIATYPE_UNKNOWN ) {
                                return $type;
                        }
                }

                // Check for entry for file extension
                if ( $path ) {
                        $i = strrpos( $path, '.' );
                        $e = strtolower( $i ? substr( $path, $i + 1 ) : '' );

                        // TODO: look at multi-extension if this fails, parse from full path
                        $type = $this->findMediaType( '.' . $e );
                        if ( $type !== MEDIATYPE_UNKNOWN ) {
                                return $type;
                        }
                }

                // Check major MIME type
                if ( $mime ) {
                        $i = strpos( $mime, '/' );
                        if ( $i !== false ) {
                                $major = substr( $mime, 0, $i );
                                $type = $this->findMediaType( $major );
                                if ( $type !== MEDIATYPE_UNKNOWN ) {
                                        return $type;
                                }
                        }
                }

                if ( !$type ) {
                        $type = MEDIATYPE_UNKNOWN;
                }

                return $type;
        }

        /**
         * Returns a media code matching the given MIME type or file extension.
         *
         * File extensions are represented by a string starting with a dot (.) to
         * distinguish them from MIME types.
         *
         * @param string $extMime
         * @return int|string
         */
        private function findMediaType( string $extMime ) {
                if ( strpos( $extMime, '.' ) === 0 ) {
                        // If it's an extension, look up the MIME types
                        $m = $this->getMimeTypesFromExtension( substr( $extMime, 1 ) );
                        if ( !$m ) {
                                return MEDIATYPE_UNKNOWN;
                        }
                } else {
                        // Normalize MIME type
                        if ( isset( $this->mimeTypeAliases[$extMime] ) ) {
                                $extMime = $this->mimeTypeAliases[$extMime];
                        }

                        $m = [ $extMime ];
                }

                foreach ( $m as $mime ) {
                        foreach ( $this->mediaTypes as $type => $codes ) {
                                if ( in_array( $mime, $codes, true ) ) {
                                        return $type;
                                }
                        }
                }

                return MEDIATYPE_UNKNOWN;
        }

        /**
         * Returns an array of media types (MEDIATYPE_xxx constants)
         *
         * @return string[]
         */
        public function getMediaTypes(): array {
                return array_keys( $this->mediaTypes );
        }

        /**
         * Check if major_mime has a value accepted by enum in a database schema.
         *
         * @since 1.42.0 (also backported to 1.39.7, 1.40.3 and 1.41.1)
         *
         * @param string $type
         * @return bool
         */
        public function isValidMajorMimeType( string $type ): bool {
                // See the definition of the `img_major_mime` enum in tables-generated.sql
                $types = [
                        'unknown',
                        'application',
                        'audio',
                        'image',
                        'text',
                        'video',
                        'message',
                        'model',
                        'multipart',
                        'chemical',
                ];

                return in_array( $type, $types );
        }
}

/** @deprecated class alias since 1.43 */
class_alias( MimeAnalyzer::class, 'MimeAnalyzer' );