feature #18823 [Cache] Add PhpArrayAdapter to use shared memory on PH…

…P 7.0 (tgalopin)

This PR was merged into the 3.2-dev branch.

Discussion
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[Cache] Add PhpArrayAdapter to use shared memory on PHP 7.0

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | WIP
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Depends on #18825

This PR aims to implement a Symfony Cache adapter able to build files optimized for OPCache memory storage. Any kind of static data that can be warmed up is a candidate for OPcache storage.

This PR is limited to the implementation of the Adapter. It's usage in the annotations caching system is implemented in the PR #18533. The aim is also to use this adapter in other contexts (validator, serializer, ...).

Commits
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28a40d2 [Cache] Add PhpArrayAdapter to use shared memory on PHP 7.0+

src/Symfony/Component/Cache/Adapter/PhpArrayAdapter.php

@@ -0,0 +1,358 @@
+<?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\Adapter;
+
+use Psr\Cache\CacheItemInterface;
+use Psr\Cache\CacheItemPoolInterface;
+use Symfony\Component\Cache\CacheItem;
+use Symfony\Component\Cache\Exception\InvalidArgumentException;
+
+/**
+ * Caches items at warm up time using a PHP array that is stored in shared memory by OPCache since PHP 7.0.
+ * Warmed up items are read-only and run-time discovered items are cached using a fallback adapter.
+ *
+ * @author Titouan Galopin <galopintitouan@gmail.com>
+ * @author Nicolas Grekas <p@tchwork.com>
+ */
+class PhpArrayAdapter implements AdapterInterface
+{
+    private $file;
+    private $values;
+    private $createCacheItem;
+    private $fallbackPool;
+
+    /**
+     * @param string           $file         The PHP file were values are cached
+     * @param AdapterInterface $fallbackPool A pool to fallback on when an item is not hit
+     */
+    public function __construct($file, AdapterInterface $fallbackPool)
+    {
+        $this->file = $file;
+        $this->fallbackPool = $fallbackPool;
+        $this->createCacheItem = \Closure::bind(
+            function ($key, $value) {
+                $item = new CacheItem();
+                $item->key = $key;
+                $item->value = $value;
+                $item->isHit = true;
+
+                return $item;
+            },
+            null,
+            CacheItem::class
+        );
+    }
+
+    /**
+     * This adapter should only be used on PHP 7.0+ to take advantage of how PHP
+     * stores arrays in its latest versions. This factory method decorates the given
+     * fallback pool with this adapter only if the current PHP version is supported.
+     *
+     * @param string $file The PHP file were values are cached
+     *
+     * @return CacheItemPoolInterface
+     */
+    public static function create($file, CacheItemPoolInterface $fallbackPool)
+    {
+        // Shared memory is available in PHP 7.0+ with OPCache enabled and in HHVM
+        if ((PHP_VERSION_ID >= 70000 && ini_get('opcache.enable')) || defined('HHVM_VERSION')) {
+            if (!$fallbackPool instanceof AdapterInterface) {
+                $fallbackPool = new ProxyAdapter($fallbackPool);
+            }
+
+            return new static($file, $fallbackPool);
+        }
+
+        return $fallbackPool;
+    }
+
+    /**
+     * Store an array of cached values.
+     *
+     * @param array $values The cached values
+     */
+    public function warmUp(array $values)
+    {
+        if (file_exists($this->file)) {
+            if (!is_file($this->file)) {
+                throw new InvalidArgumentException(sprintf('Cache path exists and is not a file: %s.', $this->file));
+            }
+
+            if (!is_writable($this->file)) {
+                throw new InvalidArgumentException(sprintf('Cache file is not writable: %s.', $this->file));
+            }
+        } else {
+            $directory = dirname($this->file);
+
+            if (!is_dir($directory) && !@mkdir($directory, 0777, true)) {
+                throw new InvalidArgumentException(sprintf('Cache directory does not exist and cannot be created: %s.', $directory));
+            }
+
+            if (!is_writable($directory)) {
+                throw new InvalidArgumentException(sprintf('Cache directory is not writable: %s.', $directory));
+            }
+        }
+
+        $dump = <<<'EOF'
+<?php
+
+// This file has been auto-generated by the Symfony Cache Component.
+
+return array(
+
+
+EOF;
+
+        foreach ($values as $key => $value) {
+            CacheItem::validateKey(is_int($key) ? (string) $key : $key);
+
+            if (null === $value || is_object($value)) {
+                try {
+                    $value = serialize($value);
+                } catch (\Exception $e) {
+                    throw new InvalidArgumentException(sprintf('Cache key "%s" has non-serializable %s value.', $key, get_class($value)), 0, $e);
+                }
+            } elseif (is_array($value)) {
+                try {
+                    $serialized = serialize($value);
+                    $unserialized = unserialize($serialized);
+                } catch (\Exception $e) {
+                    throw new InvalidArgumentException(sprintf('Cache key "%s" has non-serializable array value.', $key), 0, $e);
+                }
+                // Store arrays serialized if they contain any objects or references
+                if ($unserialized !== $value || (false !== strpos($serialized, ';R:') && preg_match('/;R:[1-9]/', $serialized))) {
+                    $value = $serialized;
+                }
+            } elseif (is_string($value)) {
+                // Serialize strings if they could be confused with serialized objects or arrays
+                if ('N;' === $value || (isset($value[2]) && ':' === $value[1])) {
+                    $value = serialize($value);
+                }
+            } elseif (!is_scalar($value)) {
+                throw new InvalidArgumentException(sprintf('Cache key "%s" has non-serializable %s value.', $key, gettype($value)));
+            }
+
+            $dump .= var_export($key, true).' => '.var_export($value, true).",\n";
+        }
+
+        $dump .= "\n);\n";
+        $dump = str_replace("' . \"\\0\" . '", "\0", $dump);
+
+        $tmpFile = uniqid($this->file);
+
+        file_put_contents($tmpFile, $dump);
+        @chmod($tmpFile, 0666);
+        unset($serialized, $unserialized, $value, $dump);
+
+        @rename($tmpFile, $this->file);
+
+        $this->values = (include $this->file) ?: array();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getItem($key)
+    {
+        if (null === $this->values) {
+            $this->initialize();
+        }
+
+        if (!is_string($key)) {
+            throw new InvalidArgumentException(sprintf('Cache key must be string, "%s" given.', is_object($key) ? get_class($key) : gettype($key)));
+        }
+
+        if (!isset($this->values[$key])) {
+            return $this->fallbackPool->getItem($key);
+        }
+
+        $value = $this->values[$key];
+
+        if ('N;' === $value) {
+            $value = null;
+        } elseif (is_string($value) && isset($value[2]) && ':' === $value[1]) {
+            $value = unserialize($value);
+        }
+
+        $f = $this->createCacheItem;
+
+        return $f($key, $value);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getItems(array $keys = array())
+    {
+        if (null === $this->values) {
+            $this->initialize();
+        }
+
+        foreach ($keys as $key) {
+            if (!is_string($key)) {
+                throw new InvalidArgumentException(sprintf('Cache key must be string, "%s" given.', is_object($key) ? get_class($key) : gettype($key)));
+            }
+        }
+
+        return $this->generateItems($keys);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function hasItem($key)
+    {
+        if (null === $this->values) {
+            $this->initialize();
+        }
+
+        if (!is_string($key)) {
+            throw new InvalidArgumentException(sprintf('Cache key must be string, "%s" given.', is_object($key) ? get_class($key) : gettype($key)));
+        }
+
+        return isset($this->values[$key]) || $this->fallbackPool->hasItem($key);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function clear()
+    {
+        $this->values = array();
+
+        $cleared = @unlink($this->file) || !file_exists($this->file);
+
+        return $this->fallbackPool->clear() && $cleared;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function deleteItem($key)
+    {
+        if (null === $this->values) {
+            $this->initialize();
+        }
+
+        if (!is_string($key)) {
+            throw new InvalidArgumentException(sprintf('Cache key must be string, "%s" given.', is_object($key) ? get_class($key) : gettype($key)));
+        }
+
+        return !isset($this->values[$key]) && $this->fallbackPool->deleteItem($key);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function deleteItems(array $keys)
+    {
+        if (null === $this->values) {
+            $this->initialize();
+        }
+
+        $deleted = true;
+        $fallbackKeys = array();
+
+        foreach ($keys as $key) {
+            if (!is_string($key)) {
+                throw new InvalidArgumentException(sprintf('Cache key must be string, "%s" given.', is_object($key) ? get_class($key) : gettype($key)));
+            }
+
+            if (isset($this->values[$key])) {
+                $deleted = false;
+            } else {
+                $fallbackKeys[] = $key;
+            }
+        }
+
+        if ($fallbackKeys) {
+            $deleted = $this->fallbackPool->deleteItems($fallbackKeys) && $deleted;
+        }
+
+        return $deleted;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function save(CacheItemInterface $item)
+    {
+        if (null === $this->values) {
+            $this->initialize();
+        }
+
+        return !isset($this->values[$item->getKey()]) && $this->fallbackPool->save($item);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function saveDeferred(CacheItemInterface $item)
+    {
+        if (null === $this->values) {
+            $this->initialize();
+        }
+
+        return !isset($this->values[$item->getKey()]) && $this->fallbackPool->saveDeferred($item);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function commit()
+    {
+        return $this->fallbackPool->commit();
+    }
+
+    /**
+     * Load the cache file.
+     */
+    private function initialize()
+    {
+        $this->values = @(include $this->file) ?: array();
+    }
+
+    /**
+     * Generator for items.
+     *
+     * @param array $keys
+     *
+     * @return \Generator
+     */
+    private function generateItems(array $keys)
+    {
+        $f = $this->createCacheItem;
+        $fallbackKeys = array();
+
+        foreach ($keys as $key) {
+            if (isset($this->values[$key])) {
+                $value = $this->values[$key];
+
+                if ('N;' === $value) {
+                    $value = null;
+                } elseif (is_string($value) && isset($value[2]) && ':' === $value[1]) {
+                    $value = unserialize($value);
+                }
+
+                yield $key => $f($key, $value);
+            } else {
+                $fallbackKeys[] = $key;
+            }
+        }
+
+        if ($fallbackKeys) {
+            foreach ($this->fallbackPool->getItems($fallbackKeys) as $key => $item) {
+                yield $key => $item;
+            }
+        }
+    }
+}