Add simplified CacheStorage implementation

To be able to use PHPStan's caching mechanism for generating
factory & proxy classes, a simplified version of a file cache
storage is added.

Author: shochdoerfer

src/bitExpert/PHPStan/Magento/Autoload/Cache/FileCacheStorage.php

@@ -0,0 +1,116 @@
+<?php
+
+/*
+ * This file is part of the phpstan-magento package.
+ *
+ * (c) bitExpert AG
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+declare(strict_types=1);
+
+namespace bitExpert\PHPStan\Magento\Autoload\Cache;
+
+use PHPStan\Cache\CacheStorage;
+
+class FileCacheStorage implements CacheStorage
+{
+    /**
+     * @var string
+     */
+    private $directory;
+
+    /**
+     * FileCacheStorage constructor.
+     *
+     * @param string $directory
+     */
+    public function __construct(string $directory)
+    {
+        $this->directory = $directory;
+    }
+
+    /**
+     * @param string $key
+     * @param string $variableKey
+     * @return mixed|string|null
+     */
+    public function load(string $key, string $variableKey)
+    {
+        return (function (string $key) {
+            $cacheDir = $this->getCacheDir($key);
+            $cacheFile = $this->getCacheFile($key);
+            if (!is_file($cacheDir . '/' . $cacheFile)) {
+                return null;
+            }
+
+            return $cacheDir . '/' . $cacheFile;
+        })($key);
+    }
+
+    /**
+     * @param string $key
+     * @param string $variableKey
+     * @param mixed $data
+     */
+    public function save(string $key, string $variableKey, $data): void
+    {
+        $cacheDir = $this->getCacheDir($key);
+        $cacheFile = $this->getCacheFile($key);
+        $this->makeDir($cacheDir);
+        $tmpSuccess = @file_put_contents($cacheDir . '/' . $cacheFile, $data);
+        if ($tmpSuccess === false) {
+            throw new \InvalidArgumentException(
+                sprintf('Could not write data to cache file %s.', $cacheDir . '/' . $cacheFile)
+            );
+        }
+    }
+
+    /**
+     * @param string $key
+     * @return string
+     */
+    private function getCacheDir(string $key): string
+    {
+        $keyHash = sha1($key);
+        $firstDirectory = sprintf('%s/%s', $this->directory, substr($keyHash, 0, 2));
+        return sprintf('%s/%s', $firstDirectory, substr($keyHash, 2, 2));
+    }
+
+    /**
+     * @param string $key
+     * @return string
+     */
+    private function getCacheFile(string $key): string
+    {
+        return sprintf('%s.php', sha1($key));
+    }
+
+    /**
+     * @param string $directory
+     */
+    private function makeDir(string $directory): void
+    {
+        if (is_dir($directory)) {
+            return;
+        }
+
+        $result = @mkdir($directory, 0777, true);
+        if ($result === \false) {
+            clearstatcache();
+            if (is_dir($directory)) {
+                return;
+            }
+
+            $error = error_get_last();
+            throw new \InvalidArgumentException(
+                sprintf(
+                    'Failed to create directory "%s" (%s).',
+                    $this->directory,
+                    $error !== null ? $error['message'] : 'unknown cause'
+                )
+            );
+        }
+    }
+}

tests/bitExpert/PHPStan/Magento/Autoload/Cache/FileCacheStorageUnitTest.php

@@ -0,0 +1,86 @@
+<?php
+
+/*
+ * This file is part of the phpstan-magento package.
+ *
+ * (c) bitExpert AG
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+declare(strict_types=1);
+
+namespace bitExpert\PHPStan\Magento\Autoload\Cache;
+
+use InvalidArgumentException;
+use org\bovigo\vfs\vfsStream;
+use org\bovigo\vfs\vfsStreamDirectory;
+use PHPUnit\Framework\TestCase;
+
+class FileCacheStorageUnitTest extends TestCase
+{
+    /**
+     * @var vfsStreamDirectory
+     */
+    private $root;
+    /**
+     * @var FileCacheStorage
+     */
+    private $storage;
+
+    public function setUp(): void
+    {
+        $this->root = vfsStream::setup('tmp');
+        $this->storage = new FileCacheStorage($this->root->url());
+    }
+
+    /**
+     * @test
+     */
+    public function nullReturnedWhenLookingUpNonExistentFileInCache()
+    {
+        $absFilename = $this->storage->load('test.txt', '');
+
+        self::assertNull($absFilename);
+    }
+
+    /**
+     * @test
+     */
+    public function absoluteFilenameReturnedWhenLookingUpExistentFileInCache()
+    {
+        vfsStream::create(
+            ['4b' => ['6f' => ['4b6fcb2d521ef0fd442a5301e7932d16cc9f375a.php' => 'Lorem ipsum']]],
+            $this->root
+        );
+
+        $absFilename = $this->storage->load('test.txt', '');
+
+        self::assertSame($absFilename, vfsStream::url('tmp/4b/6f/4b6fcb2d521ef0fd442a5301e7932d16cc9f375a.php'));
+    }
+
+    /**
+     * @test
+     */
+    public function addingFileToCacheSucceeds()
+    {
+        $this->storage->save('test.txt', '', 'Lorem ipsum');
+        $absFilename = $this->storage->load('test.txt', '');
+
+        self::assertSame($absFilename, vfsStream::url('tmp/4b/6f/4b6fcb2d521ef0fd442a5301e7932d16cc9f375a.php'));
+    }
+
+    /**
+     * @test
+     */
+    public function addingFileToCacheFails()
+    {
+        $this->expectException(InvalidArgumentException::class);
+
+        // simulate full disk
+        vfsStream::setQuota(1);
+
+        $this->storage->save('test.txt', '', 'Lorem ipsum');
+        $this->storage->load('test.txt', '');
+    }
+}