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amp/lib/PrivatePromisor.php

75 lines
2.3 KiB
PHP

<?php
namespace Amp;
/**
* A PrivatePromisor creates read-only Promise instances that can only be
* resolved by holders of the PrivatePromisor instance. This creates an
* additional layer of API protection beyond the PublicPromisor.
*/
trait PrivatePromisor {
private $resolver;
private $updater;
private $promise;
public function __construct() {
// @TODO Replace PrivatePlaceholder with an anonymous class once PHP7 is required
$placeholder = new PrivatePlaceholder;
$resolver = function($error = null, $result = null) {
// bound to private $placeholder::resolve()
$this->resolve($error, $result);
};
$updater = function($progress) {
// bound to private $placeholder::update()
\call_user_func([$this, "update"], $progress);
};
$this->resolver = $resolver->bindTo($placeholder, $placeholder);
$this->updater = $updater->bindTo($placeholder, $placeholder);
$this->promise = $placeholder;
}
/**
* Promise future fulfillment of the returned placeholder value
*
* @return \Amp\Promise
*/
public function promise() {
return $this->promise;
}
/**
* Update watchers of progress resolving the promised value
*
* @param mixed $progress1, $progress2, ... $progressN
* @return void
*/
public function update($progress) {
\call_user_func($this->updater, $progress);
}
/**
* Resolve the associated promise placeholder as a success
*
* @param mixed $result
* @return void
*/
public function succeed($result = null) {
\call_user_func($this->resolver, $error = null, $result);
}
/**
* Resolve the associated promise placeholder as a failure
*
* The error parameter used to fail a promisor must always be an exception
* instance. However, we cannot typehint this parameter in environments
* where PHP5.x compatibility is required because PHP7 Throwable
* instances will break the typehint.
*
* @param mixed $error An Exception or Throwable in PHP7 environments
* @return void
*/
public function fail($error) {
\call_user_func($this->resolver, $error, $result = null);
}
}