ExtensionRegistry.php

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<?php

use Composer\Semver\Semver;
use Wikimedia\ScopedCallback;
use MediaWiki\Shell\Shell;
use MediaWiki\ShellDisabledError;

class ExtensionRegistry {

    const MEDIAWIKI_CORE = 'MediaWiki';

    const MANIFEST_VERSION = 2;

    const MANIFEST_VERSION_MW_VERSION = '>= 1.29.0';

    const OLDEST_MANIFEST_VERSION = 1;

    const CACHE_VERSION = 7;

    const MERGE_STRATEGY = '_merge_strategy';

    private $loaded = [];

    protected $queued = [];

    private $finished = false;

    protected $attributes = [];

    protected $testAttributes = [];

    private static $instance;

    public static function getInstance() {
        if ( self::$instance === null ) {
            self::$instance = new self();
        }

        return self::$instance;
    }

    public function queue( $path ) {
        global $wgExtensionInfoMTime;

        $mtime = $wgExtensionInfoMTime;
        if ( $mtime === false ) {
            if ( file_exists( $path ) ) {
                $mtime = filemtime( $path );
            } else {
                throw new Exception( "$path does not exist!" );
            }
            // @codeCoverageIgnoreStart
            if ( $mtime === false ) {
                $err = error_get_last();
                throw new Exception( "Couldn't stat $path: {$err['message']}" );
                // @codeCoverageIgnoreEnd
            }
        }
        $this->queued[$path] = $mtime;
    }

    public function loadFromQueue() {
        global $wgVersion, $wgDevelopmentWarnings;
        if ( !$this->queued ) {
            return;
        }

        if ( $this->finished ) {
            throw new MWException(
                "The following paths tried to load late: "
                . implode( ', ', array_keys( $this->queued ) )
            );
        }

        // A few more things to vary the cache on
        $versions = [
            'registration' => self::CACHE_VERSION,
            'mediawiki' => $wgVersion,
            'abilities' => $this->getAbilities(),
        ];

        // We use a try/catch because we don't want to fail here
        // if $wgObjectCaches is not configured properly for APC setup
        try {
            // Don't use MediaWikiServices here to prevent instantiating it before extensions have
            // been loaded
            $cacheId = ObjectCache::detectLocalServerCache();
            $cache = ObjectCache::newFromId( $cacheId );
        } catch ( InvalidArgumentException $e ) {
            $cache = new EmptyBagOStuff();
        }
        // See if this queue is in APC
        $key = $cache->makeKey(
            'registration',
            md5( json_encode( $this->queued + $versions ) )
        );
        $data = $cache->get( $key );
        if ( $data ) {
            $this->exportExtractedData( $data );
        } else {
            $data = $this->readFromQueue( $this->queued );
            $this->exportExtractedData( $data );
            // Do this late since we don't want to extract it since we already
            // did that, but it should be cached
            $data['globals']['wgAutoloadClasses'] += $data['autoload'];
            unset( $data['autoload'] );
            if ( !( $data['warnings'] && $wgDevelopmentWarnings ) ) {
                // If there were no warnings that were shown, cache it
                $cache->set( $key, $data, 60 * 60 * 24 );
            }
        }
        $this->queued = [];
    }

    public function getQueue() {
        return $this->queued;
    }

    public function clearQueue() {
        $this->queued = [];
    }

    public function finish() {
        $this->finished = true;
    }

    private function getAbilities() {
        return [
            'shell' => !Shell::isDisabled(),
        ];
    }

    private function buildVersionChecker() {
        global $wgVersion;
        // array to optionally specify more verbose error messages for
        // missing abilities
        $abilityErrors = [
            'shell' => ( new ShellDisabledError() )->getMessage(),
        ];

        return new VersionChecker(
            $wgVersion,
            PHP_MAJOR_VERSION . '.' . PHP_MINOR_VERSION . '.' . PHP_RELEASE_VERSION,
            get_loaded_extensions(),
            $this->getAbilities(),
            $abilityErrors
        );
    }

    public function readFromQueue( array $queue ) {
        $autoloadClasses = [];
        $autoloadNamespaces = [];
        $autoloaderPaths = [];
        $processor = new ExtensionProcessor();
        $versionChecker = $this->buildVersionChecker();
        $extDependencies = [];
        $incompatible = [];
        $warnings = false;
        foreach ( $queue as $path => $mtime ) {
            $json = file_get_contents( $path );
            if ( $json === false ) {
                throw new Exception( "Unable to read $path, does it exist?" );
            }
            $info = json_decode( $json, /* $assoc = */ true );
            if ( !is_array( $info ) ) {
                throw new Exception( "$path is not a valid JSON file." );
            }

            if ( !isset( $info['manifest_version'] ) ) {
                wfDeprecated(
                    "{$info['name']}'s extension.json or skin.json does not have manifest_version",
                    '1.29'
                );
                $warnings = true;
                // For backwards-compatability, assume a version of 1
                $info['manifest_version'] = 1;
            }
            $version = $info['manifest_version'];
            if ( $version < self::OLDEST_MANIFEST_VERSION || $version > self::MANIFEST_VERSION ) {
                $incompatible[] = "$path: unsupported manifest_version: {$version}";
            }

            $dir = dirname( $path );
            if ( isset( $info['AutoloadClasses'] ) ) {
                $autoload = $this->processAutoLoader( $dir, $info['AutoloadClasses'] );
                $GLOBALS['wgAutoloadClasses'] += $autoload;
                $autoloadClasses += $autoload;
            }
            if ( isset( $info['AutoloadNamespaces'] ) ) {
                $autoloadNamespaces += $this->processAutoLoader( $dir, $info['AutoloadNamespaces'] );
                AutoLoader::$psr4Namespaces += $autoloadNamespaces;
            }

            // get all requirements/dependencies for this extension
            $requires = $processor->getRequirements( $info );

            // validate the information needed and add the requirements
            if ( is_array( $requires ) && $requires && isset( $info['name'] ) ) {
                $extDependencies[$info['name']] = $requires;
            }

            // Get extra paths for later inclusion
            $autoloaderPaths = array_merge( $autoloaderPaths,
                $processor->getExtraAutoloaderPaths( $dir, $info ) );
            // Compatible, read and extract info
            $processor->extractInfo( $path, $info, $version );
        }
        $data = $processor->getExtractedInfo();
        $data['warnings'] = $warnings;

        // check for incompatible extensions
        $incompatible = array_merge(
            $incompatible,
            $versionChecker
                ->setLoadedExtensionsAndSkins( $data['credits'] )
                ->checkArray( $extDependencies )
        );

        if ( $incompatible ) {
            throw new ExtensionDependencyError( $incompatible );
        }

        // Need to set this so we can += to it later
        $data['globals']['wgAutoloadClasses'] = [];
        $data['autoload'] = $autoloadClasses;
        $data['autoloaderPaths'] = $autoloaderPaths;
        $data['autoloaderNS'] = $autoloadNamespaces;
        return $data;
    }

    protected function exportExtractedData( array $info ) {
        foreach ( $info['globals'] as $key => $val ) {
            // If a merge strategy is set, read it and remove it from the value
            // so it doesn't accidentally end up getting set.
            if ( is_array( $val ) && isset( $val[self::MERGE_STRATEGY] ) ) {
                $mergeStrategy = $val[self::MERGE_STRATEGY];
                unset( $val[self::MERGE_STRATEGY] );
            } else {
                $mergeStrategy = 'array_merge';
            }

            // Optimistic: If the global is not set, or is an empty array, replace it entirely.
            // Will be O(1) performance.
            if ( !array_key_exists( $key, $GLOBALS ) || ( is_array( $GLOBALS[$key] ) && !$GLOBALS[$key] ) ) {
                $GLOBALS[$key] = $val;
                continue;
            }

            if ( !is_array( $GLOBALS[$key] ) || !is_array( $val ) ) {
                // config setting that has already been overridden, don't set it
                continue;
            }

            switch ( $mergeStrategy ) {
                case 'array_merge_recursive':
                    $GLOBALS[$key] = array_merge_recursive( $GLOBALS[$key], $val );
                    break;
                case 'array_replace_recursive':
                    $GLOBALS[$key] = array_replace_recursive( $GLOBALS[$key], $val );
                    break;
                case 'array_plus_2d':
                    $GLOBALS[$key] = wfArrayPlus2d( $GLOBALS[$key], $val );
                    break;
                case 'array_plus':
                    $GLOBALS[$key] += $val;
                    break;
                case 'array_merge':
                    $GLOBALS[$key] = array_merge( $val, $GLOBALS[$key] );
                    break;
                default:
                    throw new UnexpectedValueException( "Unknown merge strategy '$mergeStrategy'" );
            }
        }

        if ( isset( $info['autoloaderNS'] ) ) {
            AutoLoader::$psr4Namespaces += $info['autoloaderNS'];
        }

        foreach ( $info['defines'] as $name => $val ) {
            define( $name, $val );
        }
        foreach ( $info['autoloaderPaths'] as $path ) {
            if ( file_exists( $path ) ) {
                require_once $path;
            }
        }

        $this->loaded += $info['credits'];
        if ( $info['attributes'] ) {
            if ( !$this->attributes ) {
                $this->attributes = $info['attributes'];
            } else {
                $this->attributes = array_merge_recursive( $this->attributes, $info['attributes'] );
            }
        }

        foreach ( $info['callbacks'] as $name => $cb ) {
            if ( !is_callable( $cb ) ) {
                if ( is_array( $cb ) ) {
                    $cb = '[ ' . implode( ', ', $cb ) . ' ]';
                }
                throw new UnexpectedValueException( "callback '$cb' is not callable" );
            }
            $cb( $info['credits'][$name] );
        }
    }

    public function load( $path ) {
        wfDeprecated( __METHOD__, '1.34' );
        $this->loadFromQueue(); // First clear the queue
        $this->queue( $path );
        $this->loadFromQueue();
    }

    public function isLoaded( $name, $constraint = '*' ) {
        $isLoaded = isset( $this->loaded[$name] );
        if ( $constraint === '*' || !$isLoaded ) {
            return $isLoaded;
        }
        // if a specific constraint is requested, but no version is set, throw an exception
        if ( !isset( $this->loaded[$name]['version'] ) ) {
            $msg = "{$name} does not expose its version, but an extension or a skin"
                    . " requires: {$constraint}.";
            throw new LogicException( $msg );
        }

        return SemVer::satisfies( $this->loaded[$name]['version'], $constraint );
    }

    public function getAttribute( $name ) {
        return $this->testAttributes[$name] ??
            $this->attributes[$name] ?? [];
    }

    public function setAttributeForTest( $name, array $value ) {
        // @codeCoverageIgnoreStart
        if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
            throw new RuntimeException( __METHOD__ . ' can only be used in tests' );
        }
        // @codeCoverageIgnoreEnd
        if ( isset( $this->testAttributes[$name] ) ) {
            throw new Exception( "The attribute '$name' has already been overridden" );
        }
        $this->testAttributes[$name] = $value;
        return new ScopedCallback( function () use ( $name ) {
            unset( $this->testAttributes[$name] );
        } );
    }

    public function getAllThings() {
        return $this->loaded;
    }

    protected function processAutoLoader( $dir, array $files ) {
        // Make paths absolute, relative to the JSON file
        foreach ( $files as &$file ) {
            $file = "$dir/$file";
        }
        return $files;
    }
}