DynamicDefaultValues.php

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<?php
 
namespace MediaWiki\Settings;
 
use LogicException;
use MediaWiki\Settings\Config\ConfigBuilder;
use MediaWiki\Settings\Config\ConfigSchema;
 
class DynamicDefaultValues {
 
    private $configSchema;
 
    private $declarations;
 
    public function __construct( ConfigSchema $configSchema ) {
        $this->configSchema = $configSchema;
        $this->declarations = $this->configSchema->getDynamicDefaults();
    }
 
    public function applyDynamicDefaults( ConfigBuilder $configBuilder ): void {
        $alreadyComputed = [];
 
        foreach ( $this->declarations as $key => $unused ) {
            $this->computeDefaultFor( $key, $configBuilder, $alreadyComputed );
        }
    }
 
    private function computeDefaultFor(
        string $key,
        ConfigBuilder $configBuilder,
        array &$alreadyComputed = [],
        array $currentlyComputing = []
    ): void {
        if ( !isset( $this->declarations[ $key ] ) || isset( $alreadyComputed[ $key ] ) ) {
            return;
        }
        if ( isset( $currentlyComputing[ $key ] ) ) {
            throw new LogicException(
                'Cyclic dependency when computing dynamic default: ' .
                implode( ' -> ', array_keys( $currentlyComputing ) ) . " -> $key"
            );
        }
        if (
            $configBuilder->get( $key ) !==
            $this->configSchema->getDefaultFor( $key )
        ) {
            // Default was already overridden, nothing more to do
            $alreadyComputed[ $key ] = true;
 
            return;
        }
 
        $currentlyComputing[ $key ] = true;
 
        $callback = $this->declarations[ $key ]['callback'];
        $argNames = $this->declarations[ $key ]['use'] ?? [];
        $args = [];
 
        foreach ( $argNames as $argName ) {
            $this->computeDefaultFor(
                $argName,
                $configBuilder,
                $alreadyComputed,
                $currentlyComputing
            );
            $args[] = $configBuilder->get( $argName );
        }
 
        $configBuilder->set( $key, $callback( ...$args ) );
 
        $alreadyComputed[ $key ] = true;
    }
}