psalm/src/Psalm/Checker/InterfaceChecker.php

<?php

namespace Psalm\Checker;

use PhpParser;
use Psalm\StatementsSource;
use Psalm\Context;

class InterfaceChecker extends ClassLikeChecker
{
    protected $parent_interfaces = [];

    protected static $existing_interfaces = [];
    protected static $existing_interfaces_ci = [];

    public function __construct(PhpParser\Node\Stmt\Interface_ $interface, StatementsSource $source, $interface_name)
    {
        parent::__construct($interface, $source, $interface_name);

        self::$existing_interfaces[$interface_name] = true;
        self::$existing_interfaces_ci[strtolower($interface_name)] = true;

        foreach ($interface->extends as $extended_interface) {
            $this->parent_interfaces[] = self::getAbsoluteClassFromName($extended_interface, $this->namespace, $this->aliased_classes);
        }
    }

    public static function interfaceExists($interface)
    {
        if (isset(self::$existing_interfaces_ci[strtolower($interface)])) {
            return self::$existing_interfaces_ci[strtolower($interface)];
        }

        if (in_array($interface, self::$SPECIAL_TYPES)) {
            return false;
        }

        if (interface_exists($interface, true)) {
            $reflected_interface = new \ReflectionClass($interface);

            self::$existing_interfaces_ci[strtolower($interface)] = true;
            self::$existing_interfaces[$reflected_interface->getName()] = true;
            return true;
        }

        self::$existing_interfaces_ci[strtolower($interface)] = false;
        self::$existing_interfaces_ci[$interface] = false;

        return false;
    }

    public static function hasCorrectCasing($interface)
    {
        if (!self::interfaceExists(strtolower($interface))) {
            throw new \InvalidArgumentException('Cannot check casing on nonexistent class ' . $interface);
        }

        return isset(self::$existing_interfaces[$interface]);
    }

    public static function clearCache()
    {
        self::$existing_interfaces = [];
        self::$existing_interfaces_ci = [];
    }
}