FileCacheStorage.php

<?php

declare(strict_types=1);

namespace Rector\Caching\ValueObject\Storage;

use FilesystemIterator;
use Nette\Utils\FileSystem;
use Rector\Caching\Contract\ValueObject\Storage\CacheStorageInterface;
use Rector\Caching\ValueObject\CacheFilePaths;
use Rector\Caching\ValueObject\CacheItem;
use Rector\Exception\Cache\CachingException;

/**
 * Inspired by https://github.com/phpstan/phpstan-src/blob/1e7ceae933f07e5a250b61ed94799e6c2ea8daa2/src/Cache/FileCacheStorage.php
 * @see \Rector\Tests\Caching\ValueObject\Storage\FileCacheStorageTest
 */
final readonly class FileCacheStorage implements CacheStorageInterface
{
    public function __construct(
        private string $directory,
        private \Symfony\Component\Filesystem\Filesystem $filesystem
    ) {
    }

    public function load(string $key, string $variableKey): mixed
    {
        return (function (string $key, string $variableKey) {
            $cacheFilePaths = $this->getCacheFilePaths($key);

            $filePath = $cacheFilePaths->getFilePath();
            if (! \is_file($filePath)) {
                return null;
            }

            $cacheItem = (require $filePath);
            if (! $cacheItem instanceof CacheItem) {
                return null;
            }

            if (! $cacheItem->isVariableKeyValid($variableKey)) {
                return null;
            }

            return $cacheItem->getData();
        })($key, $variableKey);
    }

    public function save(string $key, string $variableKey, mixed $data): void
    {
        $cacheFilePaths = $this->getCacheFilePaths($key);
        $this->filesystem->mkdir($cacheFilePaths->getFirstDirectory());
        $this->filesystem->mkdir($cacheFilePaths->getSecondDirectory());

        $filePath = $cacheFilePaths->getFilePath();

        $errorBefore = \error_get_last();
        $exported = @\var_export(new CacheItem($variableKey, $data), true);
        $errorAfter = \error_get_last();
        if ($errorAfter !== null && $errorBefore !== $errorAfter) {
            throw new CachingException(\sprintf(
                'Error occurred while saving item %s (%s) to cache: %s',
                $key,
                $variableKey,
                $errorAfter['message']
            ));
        }

        // atomic write via temp file + rename(), so a parallel reader never sees a partially written cache file
        // handles the Windows rename() edge case too, see https://github.com/rectorphp/rector/issues/9876
        FileSystem::writeAtomic($filePath, \sprintf("<?php declare(strict_types = 1);\n\nreturn %s;", $exported), null);
    }

    public function clean(string $key): void
    {
        $cacheFilePaths = $this->getCacheFilePaths($key);
        $this->processRemoveCacheFilePath($cacheFilePaths);
        $this->processRemoveEmptyDirectory($cacheFilePaths->getSecondDirectory());
        $this->processRemoveEmptyDirectory($cacheFilePaths->getFirstDirectory());
    }

    public function clear(): void
    {
        FileSystem::delete($this->directory);
    }

    private function processRemoveCacheFilePath(CacheFilePaths $cacheFilePaths): void
    {
        $filePath = $cacheFilePaths->getFilePath();
        if (! $this->filesystem->exists($filePath)) {
            return;
        }

        FileSystem::delete($filePath);
    }

    private function processRemoveEmptyDirectory(string $directory): void
    {
        if (! $this->filesystem->exists($directory)) {
            return;
        }

        if ($this->isNotEmptyDirectory($directory)) {
            return;
        }

        FileSystem::delete($directory);
    }

    private function isNotEmptyDirectory(string $directory): bool
    {
        // FilesystemIterator will initially point to the first file in the folder - if there are no files in the folder, valid() will return false
        $filesystemIterator = new FilesystemIterator($directory);
        return $filesystemIterator->valid();
    }

    private function getCacheFilePaths(string $key): CacheFilePaths
    {
        $keyHash = sha1($key);
        $firstDirectory = sprintf('%s/%s', $this->directory, substr($keyHash, 0, 2));
        $secondDirectory = sprintf('%s/%s', $firstDirectory, substr($keyHash, 2, 2));
        $filePath = sprintf('%s/%s.php', $secondDirectory, $keyHash);

        return new CacheFilePaths($firstDirectory, $secondDirectory, $filePath);
    }
}