FileBackendGroup.php

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<?php
use MediaWiki\Logger\LoggerFactory;
use MediaWiki\MediaWikiServices;
 
class FileBackendGroup {
    protected static $instance = null;
 
    protected $backends = [];
 
    protected function __construct() {
    }
 
    public static function singleton() {
        if ( self::$instance == null ) {
            self::$instance = new self();
            self::$instance->initFromGlobals();
        }
 
        return self::$instance;
    }
 
    public static function destroySingleton() {
        self::$instance = null;
    }
 
    protected function initFromGlobals() {
        global $wgLocalFileRepo, $wgForeignFileRepos, $wgFileBackends, $wgDirectoryMode;
 
        // Register explicitly defined backends
        $this->register( $wgFileBackends, wfConfiguredReadOnlyReason() );
 
        $autoBackends = [];
        // Automatically create b/c backends for file repos...
        $repos = array_merge( $wgForeignFileRepos, [ $wgLocalFileRepo ] );
        foreach ( $repos as $info ) {
            $backendName = $info['backend'];
            if ( is_object( $backendName ) || isset( $this->backends[$backendName] ) ) {
                continue; // already defined (or set to the object for some reason)
            }
            $repoName = $info['name'];
            // Local vars that used to be FSRepo members...
            $directory = $info['directory'];
            $deletedDir = $info['deletedDir'] ?? false; // deletion disabled
            $thumbDir = $info['thumbDir'] ?? "{$directory}/thumb";
            $transcodedDir = $info['transcodedDir'] ?? "{$directory}/transcoded";
            // Get the FS backend configuration
            $autoBackends[] = [
                'name' => $backendName,
                'class' => FSFileBackend::class,
                'lockManager' => 'fsLockManager',
                'containerPaths' => [
                    "{$repoName}-public" => "{$directory}",
                    "{$repoName}-thumb" => $thumbDir,
                    "{$repoName}-transcoded" => $transcodedDir,
                    "{$repoName}-deleted" => $deletedDir,
                    "{$repoName}-temp" => "{$directory}/temp"
                ],
                'fileMode' => $info['fileMode'] ?? 0644,
                'directoryMode' => $wgDirectoryMode,
            ];
        }
 
        // Register implicitly defined backends
        $this->register( $autoBackends, wfConfiguredReadOnlyReason() );
    }
 
    protected function register( array $configs, $readOnlyReason = null ) {
        foreach ( $configs as $config ) {
            if ( !isset( $config['name'] ) ) {
                throw new InvalidArgumentException( "Cannot register a backend with no name." );
            }
            $name = $config['name'];
            if ( isset( $this->backends[$name] ) ) {
                throw new LogicException( "Backend with name '$name' already registered." );
            } elseif ( !isset( $config['class'] ) ) {
                throw new InvalidArgumentException( "Backend with name '$name' has no class." );
            }
            $class = $config['class'];
 
            if ( isset( $config['domainId'] ) ) {
                $domainId = $config['domainId'];
            } elseif ( isset( $config['wikiId'] ) ) {
                $domainId = $config['wikiId']; // b/c
            } else {
                // Only use the raw database/prefix for backwards compatibility
                $ld = WikiMap::getCurrentWikiDbDomain();
                $domainId = strlen( $ld->getTablePrefix() )
                    ? "{$ld->getDatabase()}-{$ld->getTablePrefix()}"
                    : $ld->getDatabase();
                // If the local wiki ID and local domain ID do not match, probably due to a
                // non-default schema, issue a warning. A non-default schema indicates that
                // it might be used to disambiguate different wikis.
                $wikiId = WikiMap::getWikiIdFromDbDomain( $ld );
                if ( $ld->getSchema() !== null && $domainId !== $wikiId ) {
                    wfWarn(
                        "\$wgFileBackend entry '$name' should have 'domainId' set.\n" .
                        "Legacy default 'domainId' is '$domainId' but wiki ID is '$wikiId'."
                    );
                }
            }
            $config['domainId'] = $domainId;
            $config['readOnly'] = $config['readOnly'] ?? $readOnlyReason;
 
            unset( $config['class'] ); // backend won't need this
            $this->backends[$name] = [
                'class' => $class,
                'config' => $config,
                'instance' => null
            ];
        }
    }
 
    public function get( $name ) {
        // Lazy-load the actual backend instance
        if ( !isset( $this->backends[$name]['instance'] ) ) {
            $config = $this->config( $name );
 
            $class = $config['class'];
            if ( $class === FileBackendMultiWrite::class ) {
                // @todo How can we test this? What's the intended use-case?
                foreach ( $config['backends'] as $index => $beConfig ) {
                    if ( isset( $beConfig['template'] ) ) {
                        // Config is just a modified version of a registered backend's.
                        // This should only be used when that config is used only by this backend.
                        $config['backends'][$index] += $this->config( $beConfig['template'] );
                    }
                }
            }
 
            $this->backends[$name]['instance'] = new $class( $config );
        }
 
        return $this->backends[$name]['instance'];
    }
 
    public function config( $name ) {
        if ( !isset( $this->backends[$name] ) ) {
            throw new InvalidArgumentException( "No backend defined with the name '$name'." );
        }
 
        $config = $this->backends[$name]['config'];
        $services = MediaWikiServices::getInstance();
 
        return array_merge(
            // Default backend parameters
            [
                'mimeCallback' => [ $this, 'guessMimeInternal' ],
                'obResetFunc' => 'wfResetOutputBuffers',
                'streamMimeFunc' => [ StreamFile::class, 'contentTypeFromPath' ],
                'tmpFileFactory' => $services->getTempFSFileFactory(),
                'statusWrapper' => [ Status::class, 'wrap' ],
                'wanCache' => $services->getMainWANObjectCache(),
                'srvCache' => ObjectCache::getLocalServerInstance( 'hash' ),
                'logger' => LoggerFactory::getInstance( 'FileOperation' ),
                'profiler' => function ( $section ) {
                    return Profiler::instance()->scopedProfileIn( $section );
                }
            ],
            // Configured backend parameters
            $config,
            // Resolved backend parameters
            [
                'class' => $this->backends[$name]['class'],
                'lockManager' =>
                    LockManagerGroup::singleton( $config['domainId'] )
                        ->get( $config['lockManager'] ),
                'fileJournal' => isset( $config['fileJournal'] )
                    ? FileJournal::factory( $config['fileJournal'], $name )
                    : FileJournal::factory( [ 'class' => NullFileJournal::class ], $name )
            ]
        );
    }
 
    public function backendFromPath( $storagePath ) {
        list( $backend, , ) = FileBackend::splitStoragePath( $storagePath );
        if ( $backend !== null && isset( $this->backends[$backend] ) ) {
            return $this->get( $backend );
        }
 
        return null;
    }
 
    public function guessMimeInternal( $storagePath, $content, $fsPath ) {
        $magic = MediaWiki\MediaWikiServices::getInstance()->getMimeAnalyzer();
        // Trust the extension of the storage path (caller must validate)
        $ext = FileBackend::extensionFromPath( $storagePath );
        $type = $magic->guessTypesForExtension( $ext );
        // For files without a valid extension (or one at all), inspect the contents
        if ( !$type && $fsPath ) {
            $type = $magic->guessMimeType( $fsPath, false );
        } elseif ( !$type && strlen( $content ) ) {
            $tmpFile = MediaWikiServices::getInstance()->getTempFSFileFactory()
                ->newTempFSFile( 'mime_', '' );
            file_put_contents( $tmpFile->getPath(), $content );
            $type = $magic->guessMimeType( $tmpFile->getPath(), false );
        }
        return $type ?: 'unknown/unknown';
    }
}