FileBackendGroup.php

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<?php
use MediaWiki\Config\ServiceOptions;
use MediaWiki\FileBackend\FSFile\TempFSFileFactory;
use MediaWiki\FileBackend\LockManager\LockManagerGroupFactory;
use MediaWiki\Logger\LoggerFactory;
use MediaWiki\MainConfigNames;
use MediaWiki\Output\StreamFile;
use MediaWiki\Status\Status;
use Wikimedia\ObjectFactory\ObjectFactory;
use Wikimedia\Rdbms\ReadOnlyMode;
 
class FileBackendGroup {
    protected $backends = [];
 
    private $options;
 
    private $srvCache;
 
    private $wanCache;
 
    private $mimeAnalyzer;
 
    private $lmgFactory;
 
    private $tmpFileFactory;
 
    private $objectFactory;
 
    public const CONSTRUCTOR_OPTIONS = [
        MainConfigNames::DirectoryMode,
        MainConfigNames::FileBackends,
        MainConfigNames::ForeignFileRepos,
        MainConfigNames::LocalFileRepo,
        'fallbackWikiId',
    ];
 
    public function __construct(
        ServiceOptions $options,
        ReadOnlyMode $readOnlyMode,
        BagOStuff $srvCache,
        WANObjectCache $wanCache,
        MimeAnalyzer $mimeAnalyzer,
        LockManagerGroupFactory $lmgFactory,
        TempFSFileFactory $tmpFileFactory,
        ObjectFactory $objectFactory
    ) {
        $this->options = $options;
        $this->srvCache = $srvCache;
        $this->wanCache = $wanCache;
        $this->mimeAnalyzer = $mimeAnalyzer;
        $this->lmgFactory = $lmgFactory;
        $this->tmpFileFactory = $tmpFileFactory;
        $this->objectFactory = $objectFactory;
 
        // Register explicitly defined backends
        $this->register( $options->get( MainConfigNames::FileBackends ), $readOnlyMode->getConfiguredReason() );
 
        $autoBackends = [];
        // Automatically create b/c backends for file repos...
        $repos = array_merge(
            $options->get( MainConfigNames::ForeignFileRepos ), [ $options->get( MainConfigNames::LocalFileRepo ) ] );
        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";
            $lockManager = $info['lockManager'] ?? 'fsLockManager';
            // Get the FS backend configuration
            $autoBackends[] = [
                'name' => $backendName,
                'class' => FSFileBackend::class,
                'lockManager' => $lockManager,
                'containerPaths' => [
                    "{$repoName}-public" => "{$directory}",
                    "{$repoName}-thumb" => $thumbDir,
                    "{$repoName}-transcoded" => $transcodedDir,
                    "{$repoName}-deleted" => $deletedDir,
                    "{$repoName}-temp" => "{$directory}/temp"
                ],
                'fileMode' => $info['fileMode'] ?? 0644,
                'directoryMode' => $options->get( MainConfigNames::DirectoryMode ),
            ];
        }
 
        // Register implicitly defined backends
        $this->register( $autoBackends, $readOnlyMode->getConfiguredReason() );
    }
 
    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'];
 
            $config['domainId'] ??= $config['wikiId'] ?? $this->options->get( 'fallbackWikiId' );
            $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'];
 
        return array_merge(
            // Default backend parameters
            [
                'mimeCallback' => [ $this, 'guessMimeInternal' ],
                'obResetFunc' => 'wfResetOutputBuffers',
                'streamMimeFunc' => [ StreamFile::class, 'contentTypeFromPath' ],
                'tmpFileFactory' => $this->tmpFileFactory,
                'statusWrapper' => [ Status::class, 'wrap' ],
                'wanCache' => $this->wanCache,
                'srvCache' => $this->srvCache,
                'logger' => LoggerFactory::getInstance( 'FileOperation' ),
                'profiler' => static function ( $section ) {
                    return Profiler::instance()->scopedProfileIn( $section );
                }
            ],
            // Configured backend parameters
            $config,
            // Resolved backend parameters
            [
                'class' => $this->backends[$name]['class'],
                'lockManager' =>
                    $this->lmgFactory->getLockManagerGroup( $config['domainId'] )
                        ->get( $config['lockManager'] ),
            ]
        );
    }
 
    public function backendFromPath( $storagePath ) {
        [ $backend, , ] = FileBackend::splitStoragePath( $storagePath );
        if ( $backend !== null && isset( $this->backends[$backend] ) ) {
            return $this->get( $backend );
        }
 
        return null;
    }
 
    public function guessMimeInternal( $storagePath, $content, $fsPath ) {
        // Trust the extension of the storage path (caller must validate)
        $ext = FileBackend::extensionFromPath( $storagePath );
        $type = $this->mimeAnalyzer->getMimeTypeFromExtensionOrNull( $ext );
        // For files without a valid extension (or one at all), inspect the contents
        if ( !$type && $fsPath ) {
            $type = $this->mimeAnalyzer->guessMimeType( $fsPath, false );
        } elseif ( !$type && $content !== null && $content !== '' ) {
            $tmpFile = $this->tmpFileFactory->newTempFSFile( 'mime_', '' );
            file_put_contents( $tmpFile->getPath(), $content );
            $type = $this->mimeAnalyzer->guessMimeType( $tmpFile->getPath(), false );
        }
        return $type ?: 'unknown/unknown';
    }
}