Update Composer, update everything

vendor/symfony/config/Resource/ClassExistenceResource.php

@@ -0,0 +1,169 @@
+<?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\Config\Resource;
+
+/**
+ * ClassExistenceResource represents a class existence.
+ * Freshness is only evaluated against resource existence.
+ *
+ * The resource must be a fully-qualified class name.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class ClassExistenceResource implements SelfCheckingResourceInterface, \Serializable
+{
+    private $resource;
+    private $exists;
+
+    private static $autoloadLevel = 0;
+    private static $autoloadedClass;
+    private static $existsCache = array();
+
+    /**
+     * @param string    $resource The fully-qualified class name
+     * @param bool|null $exists   Boolean when the existency check has already been done
+     */
+    public function __construct($resource, $exists = null)
+    {
+        $this->resource = $resource;
+        if (null !== $exists) {
+            $this->exists = (bool) $exists;
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __toString()
+    {
+        return $this->resource;
+    }
+
+    /**
+     * @return string The file path to the resource
+     */
+    public function getResource()
+    {
+        return $this->resource;
+    }
+
+    /**
+     * {@inheritdoc}
+     *
+     * @throws \ReflectionException when a parent class/interface/trait is not found
+     */
+    public function isFresh($timestamp)
+    {
+        $loaded = class_exists($this->resource, false) || interface_exists($this->resource, false) || trait_exists($this->resource, false);
+
+        if (null !== $exists = &self::$existsCache[(int) (0 >= $timestamp)][$this->resource]) {
+            $exists = $exists || $loaded;
+        } elseif (!$exists = $loaded) {
+            if (!self::$autoloadLevel++) {
+                spl_autoload_register(__CLASS__.'::throwOnRequiredClass');
+            }
+            $autoloadedClass = self::$autoloadedClass;
+            self::$autoloadedClass = $this->resource;
+
+            try {
+                $exists = class_exists($this->resource) || interface_exists($this->resource, false) || trait_exists($this->resource, false);
+            } catch (\ReflectionException $e) {
+                if (0 >= $timestamp) {
+                    unset(self::$existsCache[1][$this->resource]);
+                    throw $e;
+                }
+            } finally {
+                self::$autoloadedClass = $autoloadedClass;
+                if (!--self::$autoloadLevel) {
+                    spl_autoload_unregister(__CLASS__.'::throwOnRequiredClass');
+                }
+            }
+        }
+
+        if (null === $this->exists) {
+            $this->exists = $exists;
+        }
+
+        return $this->exists xor !$exists;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function serialize()
+    {
+        if (null === $this->exists) {
+            $this->isFresh(0);
+        }
+
+        return serialize(array($this->resource, $this->exists));
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function unserialize($serialized)
+    {
+        list($this->resource, $this->exists) = unserialize($serialized);
+    }
+
+    /**
+     * @throws \ReflectionException When $class is not found and is required
+     */
+    private static function throwOnRequiredClass($class)
+    {
+        if (self::$autoloadedClass === $class) {
+            return;
+        }
+        $e = new \ReflectionException("Class $class not found");
+        $trace = $e->getTrace();
+        $autoloadFrame = array(
+            'function' => 'spl_autoload_call',
+            'args' => array($class),
+        );
+        $i = 1 + array_search($autoloadFrame, $trace, true);
+
+        if (isset($trace[$i]['function']) && !isset($trace[$i]['class'])) {
+            switch ($trace[$i]['function']) {
+                case 'get_class_methods':
+                case 'get_class_vars':
+                case 'get_parent_class':
+                case 'is_a':
+                case 'is_subclass_of':
+                case 'class_exists':
+                case 'class_implements':
+                case 'class_parents':
+                case 'trait_exists':
+                case 'defined':
+                case 'interface_exists':
+                case 'method_exists':
+                case 'property_exists':
+                case 'is_callable':
+                    return;
+            }
+
+            $props = array(
+                'file' => $trace[$i]['file'],
+                'line' => $trace[$i]['line'],
+                'trace' => \array_slice($trace, 1 + $i),
+            );
+
+            foreach ($props as $p => $v) {
+                $r = new \ReflectionProperty('Exception', $p);
+                $r->setAccessible(true);
+                $r->setValue($e, $v);
+            }
+        }
+
+        throw $e;
+    }
+}

vendor/symfony/config/Resource/ComposerResource.php

@@ -0,0 +1,78 @@
+<?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\Config\Resource;
+
+/**
+ * ComposerResource tracks the PHP version and Composer dependencies.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ */
+class ComposerResource implements SelfCheckingResourceInterface, \Serializable
+{
+    private $vendors;
+
+    private static $runtimeVendors;
+
+    public function __construct()
+    {
+        self::refresh();
+        $this->vendors = self::$runtimeVendors;
+    }
+
+    public function getVendors()
+    {
+        return array_keys($this->vendors);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __toString()
+    {
+        return __CLASS__;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isFresh($timestamp)
+    {
+        self::refresh();
+
+        return self::$runtimeVendors === $this->vendors;
+    }
+
+    public function serialize()
+    {
+        return serialize($this->vendors);
+    }
+
+    public function unserialize($serialized)
+    {
+        $this->vendors = unserialize($serialized);
+    }
+
+    private static function refresh()
+    {
+        self::$runtimeVendors = array();
+
+        foreach (get_declared_classes() as $class) {
+            if ('C' === $class[0] && 0 === strpos($class, 'ComposerAutoloaderInit')) {
+                $r = new \ReflectionClass($class);
+                $v = \dirname(\dirname($r->getFileName()));
+                if (file_exists($v.'/composer/installed.json')) {
+                    self::$runtimeVendors[$v] = @filemtime($v.'/composer/installed.json');
+                }
+            }
+        }
+    }
+}

vendor/symfony/config/Resource/DirectoryResource.php

@@ -0,0 +1,116 @@
+<?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\Config\Resource;
+
+/**
+ * DirectoryResource represents a resources stored in a subdirectory tree.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class DirectoryResource implements SelfCheckingResourceInterface, \Serializable
+{
+    private $resource;
+    private $pattern;
+
+    /**
+     * @param string      $resource The file path to the resource
+     * @param string|null $pattern  A pattern to restrict monitored files
+     *
+     * @throws \InvalidArgumentException
+     */
+    public function __construct($resource, $pattern = null)
+    {
+        $this->resource = realpath($resource) ?: (file_exists($resource) ? $resource : false);
+        $this->pattern = $pattern;
+
+        if (false === $this->resource || !is_dir($this->resource)) {
+            throw new \InvalidArgumentException(sprintf('The directory "%s" does not exist.', $resource));
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __toString()
+    {
+        return md5(serialize(array($this->resource, $this->pattern)));
+    }
+
+    /**
+     * @return string The file path to the resource
+     */
+    public function getResource()
+    {
+        return $this->resource;
+    }
+
+    /**
+     * Returns the pattern to restrict monitored files.
+     *
+     * @return string|null
+     */
+    public function getPattern()
+    {
+        return $this->pattern;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isFresh($timestamp)
+    {
+        if (!is_dir($this->resource)) {
+            return false;
+        }
+
+        if ($timestamp < filemtime($this->resource)) {
+            return false;
+        }
+
+        foreach (new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($this->resource), \RecursiveIteratorIterator::SELF_FIRST) as $file) {
+            // if regex filtering is enabled only check matching files
+            if ($this->pattern && $file->isFile() && !preg_match($this->pattern, $file->getBasename())) {
+                continue;
+            }
+
+            // always monitor directories for changes, except the .. entries
+            // (otherwise deleted files wouldn't get detected)
+            if ($file->isDir() && '/..' === substr($file, -3)) {
+                continue;
+            }
+
+            // for broken links
+            try {
+                $fileMTime = $file->getMTime();
+            } catch (\RuntimeException $e) {
+                continue;
+            }
+
+            // early return if a file's mtime exceeds the passed timestamp
+            if ($timestamp < $fileMTime) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    public function serialize()
+    {
+        return serialize(array($this->resource, $this->pattern));
+    }
+
+    public function unserialize($serialized)
+    {
+        list($this->resource, $this->pattern) = unserialize($serialized);
+    }
+}

vendor/symfony/config/Resource/FileExistenceResource.php

@@ -0,0 +1,76 @@
+<?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\Config\Resource;
+
+/**
+ * FileExistenceResource represents a resource stored on the filesystem.
+ * Freshness is only evaluated against resource creation or deletion.
+ *
+ * The resource can be a file or a directory.
+ *
+ * @author Charles-Henri Bruyand <charleshenri.bruyand@gmail.com>
+ */
+class FileExistenceResource implements SelfCheckingResourceInterface, \Serializable
+{
+    private $resource;
+
+    private $exists;
+
+    /**
+     * @param string $resource The file path to the resource
+     */
+    public function __construct($resource)
+    {
+        $this->resource = (string) $resource;
+        $this->exists = file_exists($resource);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __toString()
+    {
+        return $this->resource;
+    }
+
+    /**
+     * @return string The file path to the resource
+     */
+    public function getResource()
+    {
+        return $this->resource;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isFresh($timestamp)
+    {
+        return file_exists($this->resource) === $this->exists;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function serialize()
+    {
+        return serialize(array($this->resource, $this->exists));
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function unserialize($serialized)
+    {
+        list($this->resource, $this->exists) = unserialize($serialized);
+    }
+}

vendor/symfony/config/Resource/FileResource.php

@@ -0,0 +1,75 @@
+<?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\Config\Resource;
+
+/**
+ * FileResource represents a resource stored on the filesystem.
+ *
+ * The resource can be a file or a directory.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class FileResource implements SelfCheckingResourceInterface, \Serializable
+{
+    /**
+     * @var string|false
+     */
+    private $resource;
+
+    /**
+     * @param string $resource The file path to the resource
+     *
+     * @throws \InvalidArgumentException
+     */
+    public function __construct($resource)
+    {
+        $this->resource = realpath($resource) ?: (file_exists($resource) ? $resource : false);
+
+        if (false === $this->resource) {
+            throw new \InvalidArgumentException(sprintf('The file "%s" does not exist.', $resource));
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __toString()
+    {
+        return $this->resource;
+    }
+
+    /**
+     * @return string The canonicalized, absolute path to the resource
+     */
+    public function getResource()
+    {
+        return $this->resource;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isFresh($timestamp)
+    {
+        return false !== ($filemtime = @filemtime($this->resource)) && $filemtime <= $timestamp;
+    }
+
+    public function serialize()
+    {
+        return serialize($this->resource);
+    }
+
+    public function unserialize($serialized)
+    {
+        $this->resource = unserialize($serialized);
+    }
+}

vendor/symfony/config/Resource/GlobResource.php

@@ -0,0 +1,151 @@
+<?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\Config\Resource;
+
+use Symfony\Component\Finder\Finder;
+use Symfony\Component\Finder\Glob;
+
+/**
+ * GlobResource represents a set of resources stored on the filesystem.
+ *
+ * Only existence/removal is tracked (not mtimes.)
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ */
+class GlobResource implements \IteratorAggregate, SelfCheckingResourceInterface, \Serializable
+{
+    private $prefix;
+    private $pattern;
+    private $recursive;
+    private $hash;
+
+    /**
+     * @param string $prefix    A directory prefix
+     * @param string $pattern   A glob pattern
+     * @param bool   $recursive Whether directories should be scanned recursively or not
+     *
+     * @throws \InvalidArgumentException
+     */
+    public function __construct($prefix, $pattern, $recursive)
+    {
+        $this->prefix = realpath($prefix) ?: (file_exists($prefix) ? $prefix : false);
+        $this->pattern = $pattern;
+        $this->recursive = $recursive;
+
+        if (false === $this->prefix) {
+            throw new \InvalidArgumentException(sprintf('The path "%s" does not exist.', $prefix));
+        }
+    }
+
+    public function getPrefix()
+    {
+        return $this->prefix;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __toString()
+    {
+        return 'glob.'.$this->prefix.$this->pattern.(int) $this->recursive;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isFresh($timestamp)
+    {
+        $hash = $this->computeHash();
+
+        if (null === $this->hash) {
+            $this->hash = $hash;
+        }
+
+        return $this->hash === $hash;
+    }
+
+    public function serialize()
+    {
+        if (null === $this->hash) {
+            $this->hash = $this->computeHash();
+        }
+
+        return serialize(array($this->prefix, $this->pattern, $this->recursive, $this->hash));
+    }
+
+    public function unserialize($serialized)
+    {
+        list($this->prefix, $this->pattern, $this->recursive, $this->hash) = unserialize($serialized);
+    }
+
+    public function getIterator()
+    {
+        if (!file_exists($this->prefix) || (!$this->recursive && '' === $this->pattern)) {
+            return;
+        }
+
+        if (0 !== strpos($this->prefix, 'phar://') && false === strpos($this->pattern, '/**/') && (\defined('GLOB_BRACE') || false === strpos($this->pattern, '{'))) {
+            foreach (glob($this->prefix.$this->pattern, \defined('GLOB_BRACE') ? GLOB_BRACE : 0) as $path) {
+                if ($this->recursive && is_dir($path)) {
+                    $files = iterator_to_array(new \RecursiveIteratorIterator(
+                        new \RecursiveCallbackFilterIterator(
+                            new \RecursiveDirectoryIterator($path, \FilesystemIterator::SKIP_DOTS | \FilesystemIterator::FOLLOW_SYMLINKS),
+                            function (\SplFileInfo $file) { return '.' !== $file->getBasename()[0]; }
+                        ),
+                        \RecursiveIteratorIterator::LEAVES_ONLY
+                    ));
+                    uasort($files, function (\SplFileInfo $a, \SplFileInfo $b) {
+                        return (string) $a > (string) $b ? 1 : -1;
+                    });
+
+                    foreach ($files as $path => $info) {
+                        if ($info->isFile()) {
+                            yield $path => $info;
+                        }
+                    }
+                } elseif (is_file($path)) {
+                    yield $path => new \SplFileInfo($path);
+                }
+            }
+
+            return;
+        }
+
+        if (!class_exists(Finder::class)) {
+            throw new \LogicException(sprintf('Extended glob pattern "%s" cannot be used as the Finder component is not installed.', $this->pattern));
+        }
+
+        $finder = new Finder();
+        $regex = Glob::toRegex($this->pattern);
+        if ($this->recursive) {
+            $regex = substr_replace($regex, '(/|$)', -2, 1);
+        }
+
+        $prefixLen = \strlen($this->prefix);
+        foreach ($finder->followLinks()->sortByName()->in($this->prefix) as $path => $info) {
+            if (preg_match($regex, substr('\\' === \DIRECTORY_SEPARATOR ? str_replace('\\', '/', $path) : $path, $prefixLen)) && $info->isFile()) {
+                yield $path => $info;
+            }
+        }
+    }
+
+    private function computeHash()
+    {
+        $hash = hash_init('md5');
+
+        foreach ($this->getIterator() as $path => $info) {
+            hash_update($hash, $path."\n");
+        }
+
+        return hash_final($hash);
+    }
+}

vendor/symfony/config/Resource/ReflectionClassResource.php

@@ -0,0 +1,200 @@
+<?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\Config\Resource;
+
+use Symfony\Component\DependencyInjection\ServiceSubscriberInterface;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+/**
+ * @author Nicolas Grekas <p@tchwork.com>
+ */
+class ReflectionClassResource implements SelfCheckingResourceInterface, \Serializable
+{
+    private $files = array();
+    private $className;
+    private $classReflector;
+    private $excludedVendors = array();
+    private $hash;
+
+    public function __construct(\ReflectionClass $classReflector, $excludedVendors = array())
+    {
+        $this->className = $classReflector->name;
+        $this->classReflector = $classReflector;
+        $this->excludedVendors = $excludedVendors;
+    }
+
+    public function isFresh($timestamp)
+    {
+        if (null === $this->hash) {
+            $this->hash = $this->computeHash();
+            $this->loadFiles($this->classReflector);
+        }
+
+        foreach ($this->files as $file => $v) {
+            if (false === $filemtime = @filemtime($file)) {
+                return false;
+            }
+
+            if ($filemtime > $timestamp) {
+                return $this->hash === $this->computeHash();
+            }
+        }
+
+        return true;
+    }
+
+    public function __toString()
+    {
+        return 'reflection.'.$this->className;
+    }
+
+    public function serialize()
+    {
+        if (null === $this->hash) {
+            $this->hash = $this->computeHash();
+            $this->loadFiles($this->classReflector);
+        }
+
+        return serialize(array($this->files, $this->className, $this->hash));
+    }
+
+    public function unserialize($serialized)
+    {
+        list($this->files, $this->className, $this->hash) = unserialize($serialized);
+    }
+
+    private function loadFiles(\ReflectionClass $class)
+    {
+        foreach ($class->getInterfaces() as $v) {
+            $this->loadFiles($v);
+        }
+        do {
+            $file = $class->getFileName();
+            if (false !== $file && file_exists($file)) {
+                foreach ($this->excludedVendors as $vendor) {
+                    if (0 === strpos($file, $vendor) && false !== strpbrk(substr($file, \strlen($vendor), 1), '/'.\DIRECTORY_SEPARATOR)) {
+                        $file = false;
+                        break;
+                    }
+                }
+                if ($file) {
+                    $this->files[$file] = null;
+                }
+            }
+            foreach ($class->getTraits() as $v) {
+                $this->loadFiles($v);
+            }
+        } while ($class = $class->getParentClass());
+    }
+
+    private function computeHash()
+    {
+        if (null === $this->classReflector) {
+            try {
+                $this->classReflector = new \ReflectionClass($this->className);
+            } catch (\ReflectionException $e) {
+                // the class does not exist anymore
+                return false;
+            }
+        }
+        $hash = hash_init('md5');
+
+        foreach ($this->generateSignature($this->classReflector) as $info) {
+            hash_update($hash, $info);
+        }
+
+        return hash_final($hash);
+    }
+
+    private function generateSignature(\ReflectionClass $class)
+    {
+        yield $class->getDocComment();
+        yield (int) $class->isFinal();
+        yield (int) $class->isAbstract();
+
+        if ($class->isTrait()) {
+            yield print_r(class_uses($class->name), true);
+        } else {
+            yield print_r(class_parents($class->name), true);
+            yield print_r(class_implements($class->name), true);
+            yield print_r($class->getConstants(), true);
+        }
+
+        if (!$class->isInterface()) {
+            $defaults = $class->getDefaultProperties();
+
+            foreach ($class->getProperties(\ReflectionProperty::IS_PUBLIC | \ReflectionProperty::IS_PROTECTED) as $p) {
+                yield $p->getDocComment().$p;
+                yield print_r($defaults[$p->name], true);
+            }
+        }
+
+        if (\defined('HHVM_VERSION')) {
+            foreach ($class->getMethods(\ReflectionMethod::IS_PUBLIC | \ReflectionMethod::IS_PROTECTED) as $m) {
+                // workaround HHVM bug with variadics, see https://github.com/facebook/hhvm/issues/5762
+                yield preg_replace('/^  @@.*/m', '', new ReflectionMethodHhvmWrapper($m->class, $m->name));
+            }
+        } else {
+            foreach ($class->getMethods(\ReflectionMethod::IS_PUBLIC | \ReflectionMethod::IS_PROTECTED) as $m) {
+                yield preg_replace('/^  @@.*/m', '', $m);
+
+                $defaults = array();
+                foreach ($m->getParameters() as $p) {
+                    $defaults[$p->name] = $p->isDefaultValueAvailable() ? $p->getDefaultValue() : null;
+                }
+                yield print_r($defaults, true);
+            }
+        }
+
+        if ($class->isAbstract() || $class->isInterface() || $class->isTrait()) {
+            return;
+        }
+
+        if (interface_exists(EventSubscriberInterface::class, false) && $class->isSubclassOf(EventSubscriberInterface::class)) {
+            yield EventSubscriberInterface::class;
+            yield print_r(\call_user_func(array($class->name, 'getSubscribedEvents')), true);
+        }
+
+        if (interface_exists(ServiceSubscriberInterface::class, false) && $class->isSubclassOf(ServiceSubscriberInterface::class)) {
+            yield ServiceSubscriberInterface::class;
+            yield print_r(\call_user_func(array($class->name, 'getSubscribedServices')), true);
+        }
+    }
+}
+
+/**
+ * @internal
+ */
+class ReflectionMethodHhvmWrapper extends \ReflectionMethod
+{
+    public function getParameters()
+    {
+        $params = array();
+
+        foreach (parent::getParameters() as $i => $p) {
+            $params[] = new ReflectionParameterHhvmWrapper(array($this->class, $this->name), $i);
+        }
+
+        return $params;
+    }
+}
+
+/**
+ * @internal
+ */
+class ReflectionParameterHhvmWrapper extends \ReflectionParameter
+{
+    public function getDefaultValue()
+    {
+        return array($this->isVariadic(), $this->isDefaultValueAvailable() ? parent::getDefaultValue() : null);
+    }
+}

vendor/symfony/config/Resource/ResourceInterface.php

@@ -0,0 +1,33 @@
+<?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\Config\Resource;
+
+/**
+ * ResourceInterface is the interface that must be implemented by all Resource classes.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+interface ResourceInterface
+{
+    /**
+     * Returns a string representation of the Resource.
+     *
+     * This method is necessary to allow for resource de-duplication, for example by means
+     * of array_unique(). The string returned need not have a particular meaning, but has
+     * to be identical for different ResourceInterface instances referring to the same
+     * resource; and it should be unlikely to collide with that of other, unrelated
+     * resource instances.
+     *
+     * @return string A string representation unique to the underlying Resource
+     */
+    public function __toString();
+}

vendor/symfony/config/Resource/SelfCheckingResourceChecker.php

@@ -0,0 +1,36 @@
+<?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\Config\Resource;
+
+use Symfony\Component\Config\ResourceCheckerInterface;
+
+/**
+ * Resource checker for instances of SelfCheckingResourceInterface.
+ *
+ * As these resources perform the actual check themselves, we can provide
+ * this class as a standard way of validating them.
+ *
+ * @author Matthias Pigulla <mp@webfactory.de>
+ */
+class SelfCheckingResourceChecker implements ResourceCheckerInterface
+{
+    public function supports(ResourceInterface $metadata)
+    {
+        return $metadata instanceof SelfCheckingResourceInterface;
+    }
+
+    public function isFresh(ResourceInterface $resource, $timestamp)
+    {
+        /* @var SelfCheckingResourceInterface $resource */
+        return $resource->isFresh($timestamp);
+    }
+}

vendor/symfony/config/Resource/SelfCheckingResourceInterface.php

@@ -0,0 +1,30 @@
+<?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\Config\Resource;
+
+/**
+ * Interface for Resources that can check for freshness autonomously,
+ * without special support from external services.
+ *
+ * @author Matthias Pigulla <mp@webfactory.de>
+ */
+interface SelfCheckingResourceInterface extends ResourceInterface
+{
+    /**
+     * Returns true if the resource has not been updated since the given timestamp.
+     *
+     * @param int $timestamp The last time the resource was loaded
+     *
+     * @return bool True if the resource has not been updated, false otherwise
+     */
+    public function isFresh($timestamp);
+}