192 lines
5 KiB
PHP
192 lines
5 KiB
PHP
<?php
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/**
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* Zend Framework (http://framework.zend.com/)
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*
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* @link http://github.com/zendframework/zf2 for the canonical source repository
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* @copyright Copyright (c) 2005-2015 Zend Technologies USA Inc. (http://www.zend.com)
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* @license http://framework.zend.com/license/new-bsd New BSD License
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*/
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namespace Zend\Stdlib;
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use ReflectionClass;
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/**
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* CallbackHandler
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*
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* A handler for an event, event, filterchain, etc. Abstracts PHP callbacks,
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* primarily to allow for lazy-loading and ensuring availability of default
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* arguments (currying).
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*/
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class CallbackHandler
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{
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/**
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* @var string|array|callable PHP callback to invoke
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*/
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protected $callback;
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/**
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* Callback metadata, if any
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* @var array
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*/
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protected $metadata;
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/**
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* Constructor
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*
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* @param string|array|object|callable $callback PHP callback
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* @param array $metadata Callback metadata
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*/
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public function __construct($callback, array $metadata = [])
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{
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$this->metadata = $metadata;
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$this->registerCallback($callback);
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}
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/**
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* Registers the callback provided in the constructor
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*
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* @param callable $callback
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* @throws Exception\InvalidCallbackException
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* @return void
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*/
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protected function registerCallback($callback)
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{
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if (!is_callable($callback)) {
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throw new Exception\InvalidCallbackException('Invalid callback provided; not callable');
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}
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$this->callback = $callback;
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}
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/**
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* Retrieve registered callback
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*
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* @return callable
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*/
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public function getCallback()
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{
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return $this->callback;
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}
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/**
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* Invoke handler
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*
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* @param array $args Arguments to pass to callback
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* @return mixed
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*/
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public function call(array $args = [])
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{
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$callback = $this->getCallback();
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$argCount = count($args);
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if (is_string($callback)) {
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$result = $this->validateStringCallbackFor54($callback);
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if ($result !== true && $argCount <= 3) {
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$callback = $result;
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// Minor performance tweak, if the callback gets called more
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// than once
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$this->callback = $result;
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}
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}
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// Minor performance tweak; use call_user_func() until > 3 arguments
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// reached
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switch ($argCount) {
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case 0:
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return $callback();
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case 1:
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return $callback(array_shift($args));
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case 2:
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$arg1 = array_shift($args);
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$arg2 = array_shift($args);
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return $callback($arg1, $arg2);
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case 3:
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$arg1 = array_shift($args);
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$arg2 = array_shift($args);
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$arg3 = array_shift($args);
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return $callback($arg1, $arg2, $arg3);
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default:
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return call_user_func_array($callback, $args);
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}
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}
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/**
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* Invoke as functor
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*
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* @return mixed
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*/
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public function __invoke()
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{
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return $this->call(func_get_args());
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}
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/**
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* Get all callback metadata
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*
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* @return array
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*/
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public function getMetadata()
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{
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return $this->metadata;
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}
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/**
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* Retrieve a single metadatum
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*
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* @param string $name
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* @return mixed
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*/
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public function getMetadatum($name)
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{
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if (array_key_exists($name, $this->metadata)) {
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return $this->metadata[$name];
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}
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return;
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}
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/**
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* Validate a static method call
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*
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*
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* @param string $callback
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* @return true|array
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* @throws Exception\InvalidCallbackException if invalid
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*/
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protected function validateStringCallbackFor54($callback)
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{
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if (!strstr($callback, '::')) {
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return true;
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}
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list($class, $method) = explode('::', $callback, 2);
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if (!class_exists($class)) {
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throw new Exception\InvalidCallbackException(sprintf(
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'Static method call "%s" refers to a class that does not exist',
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$callback
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));
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}
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$r = new ReflectionClass($class);
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if (!$r->hasMethod($method)) {
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throw new Exception\InvalidCallbackException(sprintf(
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'Static method call "%s" refers to a method that does not exist',
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$callback
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));
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}
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$m = $r->getMethod($method);
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if (!$m->isStatic()) {
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throw new Exception\InvalidCallbackException(sprintf(
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'Static method call "%s" refers to a method that is not static',
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$callback
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));
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}
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// returning a non boolean value may not be nice for a validate method,
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// but that allows the usage of a static string callback without using
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// the call_user_func function.
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return [$class, $method];
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}
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}
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