psalm/src/Psalm/Provider/FileProvider.php

<?php
namespace Psalm\Provider;

class FileProvider
{
    /**
     * @param  string  $file_path
     *
     * @return string
     */
    public function getContents($file_path)
    {
        return (string)file_get_contents($file_path);
    }

    /**
     * @param  string  $file_path
     * @param  string  $file_contents
     *
     * @return void
     */
    public function setContents($file_path, $file_contents)
    {
        file_put_contents($file_path, $file_contents);
    }

    /**
     * @param  string $file_path
     *
     * @return int
     */
    public function getModifiedTime($file_path)
    {
        return (int)filemtime($file_path);
    }

    /**
     * @param  string $file_path
     *
     * @return bool
     */
    public function fileExists($file_path)
    {
        return file_exists($file_path);
    }

    /**
     * @param string $dir_path
     * @param array<string> $file_extensions
     *
     * @return array<int, string>
     */
    public function getFilesInDir($dir_path, array $file_extensions)
    {
        $file_paths = [];

        /** @var \RecursiveDirectoryIterator */
        $iterator = new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($dir_path));
        $iterator->rewind();

        while ($iterator->valid()) {
            if (!$iterator->isDot()) {
                $extension = $iterator->getExtension();
                if (in_array($extension, $file_extensions, true)) {
                    $file_paths[] = (string)$iterator->getRealPath();
                }
            }

            $iterator->next();
        }

        return $file_paths;
    }
}