1 files changed, 166 insertions, 0 deletions

diff --git a/vendor/symfony/cache/LockRegistry.php b/vendor/symfony/cache/LockRegistry.php
new file mode 100644
index 0000000..c5c5fde
--- /dev/null
+++ b/vendor/symfony/cache/LockRegistry.php
@@ -0,0 +1,166 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Cache;
+
+use Psr\Log\LoggerInterface;
+use Symfony\Contracts\Cache\CacheInterface;
+use Symfony\Contracts\Cache\ItemInterface;
+
+/**
+ * LockRegistry is used internally by existing adapters to protect against cache stampede.
+ *
+ * It does so by wrapping the computation of items in a pool of locks.
+ * Foreach each apps, there can be at most 20 concurrent processes that
+ * compute items at the same time and only one per cache-key.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ */
+final class LockRegistry
+{
+    private static array $openedFiles = [];
+    private static ?array $lockedFiles = null;
+    private static \Exception $signalingException;
+    private static \Closure $signalingCallback;
+
+    /**
+     * The number of items in this list controls the max number of concurrent processes.
+     */
+    private static array $files = [
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'AbstractAdapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'AbstractTagAwareAdapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'AdapterInterface.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'ApcuAdapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'ArrayAdapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'ChainAdapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'CouchbaseBucketAdapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'CouchbaseCollectionAdapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'DoctrineDbalAdapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'FilesystemAdapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'FilesystemTagAwareAdapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'MemcachedAdapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'NullAdapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'ParameterNormalizer.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'PdoAdapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'PhpArrayAdapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'PhpFilesAdapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'ProxyAdapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'Psr16Adapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'RedisAdapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'RedisTagAwareAdapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'TagAwareAdapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'TagAwareAdapterInterface.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'TraceableAdapter.php',
+        __DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'TraceableTagAwareAdapter.php',
+    ];
+
+    /**
+     * Defines a set of existing files that will be used as keys to acquire locks.
+     *
+     * @return array The previously defined set of files
+     */
+    public static function setFiles(array $files): array
+    {
+        $previousFiles = self::$files;
+        self::$files = $files;
+
+        foreach (self::$openedFiles as $file) {
+            if ($file) {
+                flock($file, \LOCK_UN);
+                fclose($file);
+            }
+        }
+        self::$openedFiles = self::$lockedFiles = [];
+
+        return $previousFiles;
+    }
+
+    public static function compute(callable $callback, ItemInterface $item, bool &$save, CacheInterface $pool, ?\Closure $setMetadata = null, ?LoggerInterface $logger = null): mixed
+    {
+        if ('\\' === \DIRECTORY_SEPARATOR && null === self::$lockedFiles) {
+            // disable locking on Windows by default
+            self::$files = self::$lockedFiles = [];
+        }
+
+        $key = self::$files ? abs(crc32($item->getKey())) % \count(self::$files) : -1;
+
+        if ($key < 0 || self::$lockedFiles || !$lock = self::open($key)) {
+            return $callback($item, $save);
+        }
+
+        self::$signalingException ??= unserialize("O:9:\"Exception\":1:{s:16:\"\0Exception\0trace\";a:0:{}}");
+        self::$signalingCallback ??= fn () => throw self::$signalingException;
+
+        while (true) {
+            try {
+                // race to get the lock in non-blocking mode
+                $locked = flock($lock, \LOCK_EX | \LOCK_NB, $wouldBlock);
+
+                if ($locked || !$wouldBlock) {
+                    $logger?->info(sprintf('Lock %s, now computing item "{key}"', $locked ? 'acquired' : 'not supported'), ['key' => $item->getKey()]);
+                    self::$lockedFiles[$key] = true;
+
+                    $value = $callback($item, $save);
+
+                    if ($save) {
+                        if ($setMetadata) {
+                            $setMetadata($item);
+                        }
+
+                        $pool->save($item->set($value));
+                        $save = false;
+                    }
+
+                    return $value;
+                }
+                // if we failed the race, retry locking in blocking mode to wait for the winner
+                $logger?->info('Item "{key}" is locked, waiting for it to be released', ['key' => $item->getKey()]);
+                flock($lock, \LOCK_SH);
+            } finally {
+                flock($lock, \LOCK_UN);
+                unset(self::$lockedFiles[$key]);
+            }
+
+            try {
+                $value = $pool->get($item->getKey(), self::$signalingCallback, 0);
+                $logger?->info('Item "{key}" retrieved after lock was released', ['key' => $item->getKey()]);
+                $save = false;
+
+                return $value;
+            } catch (\Exception $e) {
+                if (self::$signalingException !== $e) {
+                    throw $e;
+                }
+                $logger?->info('Item "{key}" not found while lock was released, now retrying', ['key' => $item->getKey()]);
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * @return resource|false
+     */
+    private static function open(int $key)
+    {
+        if (null !== $h = self::$openedFiles[$key] ?? null) {
+            return $h;
+        }
+        set_error_handler(static fn () => null);
+        try {
+            $h = fopen(self::$files[$key], 'r+');
+        } finally {
+            restore_error_handler();
+        }
+
+        return self::$openedFiles[$key] = $h ?: @fopen(self::$files[$key], 'r');
+    }
+}