wikimedia/mediawiki-extensions-Translate

<?php
declare( strict_types = 1 );

namespace MediaWiki\Extension\Translate\MessageLoading;

use Cdb\Reader;
use Cdb\Writer;
use MediaWiki\Extension\Translate\Utilities\Utilities;

/**
 * Storage on CDB files.
 *
 * This is improved version of SerializedMessageIndex. It uses CDB files
 * for storage, which means it provides random access. The CDB files are
 * about double the size of serialized files (~7M for 50000 keys).
 *
 * Loading the whole index is slower than serialized, but about the same
 * as for database. Suitable for single-server setups where
 * SerializedMessageIndex is too slow for loading the whole index.
 */
class CDBMessageIndex extends MessageIndexStore {
    private ?array $index = null;
    private ?Reader $reader = null;
    private const FILENAME = 'translate_messageindex.cdb';

    public function retrieve( bool $readLatest = false ): array {
        $reader = $this->getReader();
        if ( $this->index !== null ) {
            return $this->index;
        }

        $this->index = [];
        foreach ( $this->getKeys() as $key ) {
            $this->index[$key] = $this->unserialize( $reader->get( $key ) );
        }

        return $this->index;
    }

    public function getKeys(): array {
        $reader = $this->getReader();
        $keys = [];
        $key = $reader->firstkey();
        while ( $key !== false ) {
            $keys[] = $key;
            $key = $reader->nextkey();
        }

        return $keys;
    }

    /** @inheritDoc */
    public function get( string $key ) {
        $reader = $this->getReader();
        // We might have the full cache loaded
        if ( $this->index !== null ) {
            return $this->index[$key] ?? null;
        }

        $value = $reader->get( $key );
        return is_string( $value ) ? $this->unserialize( $value ) : null;
    }

    /** @inheritDoc */
    public function store( array $array, array $diff ): void {
        $this->reader = null;

        $file = Utilities::cacheFile( self::FILENAME );
        $cache = Writer::open( $file );

        foreach ( $array as $key => $value ) {
            $value = $this->serialize( $value );
            $cache->set( $key, $value );
        }

        $cache->close();

        $this->index = $array;
    }

    private function getReader() {
        if ( $this->reader ) {
            return $this->reader;
        }

        $file = Utilities::cacheFile( self::FILENAME );
        if ( !file_exists( $file ) ) {
            // Create an empty index
            $this->store( [], [] );
        }

        $this->reader = Reader::open( $file );
        return $this->reader;
    }
}