:$strategies;
    }
    /**
     * Append a strategy at the end of the strategy queue.
     *
     * @param string $strategy Fully qualified class name of a DiscoveryStrategy
     */
    public static function appendStrategy($strategy)
    {
        self::$strategies[] = $strategy;
        self::clearCache();
    }
    /**
     * Prepend a strategy at the beginning of the strategy queue.
     *
     * @param string $strategy Fully qualified class name to a DiscoveryStrategy
     */
    public static function prependStrategy($strategy)
    {
        array_unshift(self::$strategies, $strategy);
        self::clearCache();
    }
    public static function clearCache()
    {
        self::$cache = [];
    }
    /**
     * Evaluates conditions to boolean.
     *
     * @return bool
     */
    protected static function evaluateCondition($condition)
    {
        if (is_string($condition)) {
            // Should be extended for functions, extensions???
            return self::safeClassExists($condition);
        }
        if (is_callable($condition)) {
            return (bool) $condition();
        }
        if (is_bool($condition)) {
            return $condition;
        }
        if (is_array($condition)) {
            foreach ($condition as $c) {
                if (\false === static::evaluateCondition($c)) {
                    // Immediately stop execution if the condition is false
                    return \false;
                }
            }
            return \true;
        }
        return \false;
    }
    /**
     * Get an instance of the $class.
     *
     * @param string|\Closure $class a FQCN of a class or a closure that instantiate the class
     *
     * @return object
     *
     * @throws ClassInstantiationFailedException
     */
    protected static function instantiateClass($class)
    {
        try {
            if (is_string($class)) {
                return new $class();
            }
            if (is_callable($class)) {
                return $class();
            }
        } catch (\Exception $e) {
            throw new ClassInstantiationFailedException('Unexpected exception when instantiating class.', 0, $e);
        }
        throw new ClassInstantiationFailedException('Could not instantiate class because parameter is neither a callable nor a string');
    }
    /**
     * We need a "safe" version of PHP's "class_exists" because Magento has a bug
     * (or they call it a "feature"). Magento is throwing an exception if you do class_exists()
     * on a class that ends with "Factory" and if that file does not exits.
     *
     * This function catches all potential exceptions and makes sure to always return a boolean.
     *
     * @param string $class
     *
     * @return bool
     */
    public static function safeClassExists($class)
    {
        try {
            return class_exists($class) || interface_exists($class);
        } catch (\Exception $e) {
            return \false;
        }
    }
}