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File: application/modules/extensions/aws/GuzzleHttp/Promise/Promise.php

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File: application/modules/extensions/aws/GuzzleHttp/Promise/Promise.php
Role: Application script
Content type: text/plain
Description: Application script
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<?php
namespace GuzzleHttp\Promise;

/**
 * Promises/A+ implementation that avoids recursion when possible.
 *
 * @link https://promisesaplus.com/
 */
class Promise implements PromiseInterface
{
    private
$state = self::PENDING;
    private
$result;
    private
$cancelFn;
    private
$waitFn;
    private
$waitList;
    private
$handlers = [];

   
/**
     * @param callable $waitFn Fn that when invoked resolves the promise.
     * @param callable $cancelFn Fn that when invoked cancels the promise.
     */
   
public function __construct(
        callable
$waitFn = null,
        callable
$cancelFn = null
   
) {
       
$this->waitFn = $waitFn;
       
$this->cancelFn = $cancelFn;
    }

    public function
then(
        callable
$onFulfilled = null,
        callable
$onRejected = null
   
) {
        if (
$this->state === self::PENDING) {
           
$p = new Promise(null, [$this, 'cancel']);
           
$this->handlers[] = [$p, $onFulfilled, $onRejected];
           
$p->waitList = $this->waitList;
           
$p->waitList[] = $this;
            return
$p;
        }

       
// Return a fulfilled promise and immediately invoke any callbacks.
       
if ($this->state === self::FULFILLED) {
            return
$onFulfilled
               
? promise_for($this->result)->then($onFulfilled)
                :
promise_for($this->result);
        }

       
// It's either cancelled or rejected, so return a rejected promise
        // and immediately invoke any callbacks.
       
$rejection = rejection_for($this->result);
        return
$onRejected ? $rejection->then(null, $onRejected) : $rejection;
    }

    public function
otherwise(callable $onRejected)
    {
        return
$this->then(null, $onRejected);
    }

    public function
wait($unwrap = true)
    {
       
$this->waitIfPending();

        if (!
$unwrap) {
            return
null;
        }

        if (
$this->result instanceof PromiseInterface) {
            return
$this->result->wait($unwrap);
        } elseif (
$this->state === self::FULFILLED) {
            return
$this->result;
        } else {
           
// It's rejected so "unwrap" and throw an exception.
           
throw exception_for($this->result);
        }
    }

    public function
getState()
    {
        return
$this->state;
    }

    public function
cancel()
    {
        if (
$this->state !== self::PENDING) {
            return;
        }

       
$this->waitFn = $this->waitList = null;

        if (
$this->cancelFn) {
           
$fn = $this->cancelFn;
           
$this->cancelFn = null;
            try {
               
$fn();
            } catch (\
Exception $e) {
               
$this->reject($e);
            }
        }

       
// Reject the promise only if it wasn't rejected in a then callback.
       
if ($this->state === self::PENDING) {
           
$this->reject(new CancellationException('Promise has been cancelled'));
        }
    }

    public function
resolve($value)
    {
       
$this->settle(self::FULFILLED, $value);
    }

    public function
reject($reason)
    {
       
$this->settle(self::REJECTED, $reason);
    }

    private function
settle($state, $value)
    {
        if (
$this->state !== self::PENDING) {
           
// Ignore calls with the same resolution.
           
if ($state === $this->state && $value === $this->result) {
                return;
            }
            throw
$this->state === $state
               
? new \LogicException("The promise is already {$state}.")
                : new \
LogicException("Cannot change a {$this->state} promise to {$state}");
        }

        if (
$value === $this) {
            throw new \
LogicException('Cannot fulfill or reject a promise with itself');
        }

       
// Clear out the state of the promise but stash the handlers.
       
$this->state = $state;
       
$this->result = $value;
       
$handlers = $this->handlers;
       
$this->handlers = null;
       
$this->waitList = $this->waitFn = null;
       
$this->cancelFn = null;

        if (!
$handlers) {
            return;
        }

       
// If the value was not a settled promise or a thenable, then resolve
        // it in the task queue using the correct ID.
       
if (!method_exists($value, 'then')) {
           
$id = $state === self::FULFILLED ? 1 : 2;
           
// It's a success, so resolve the handlers in the queue.
           
queue()->add(static function () use ($id, $value, $handlers) {
                foreach (
$handlers as $handler) {
                   
self::callHandler($id, $value, $handler);
                }
            });
        } elseif (
$value instanceof Promise
           
&& $value->getState() === self::PENDING
       
) {
           
// We can just merge our handlers onto the next promise.
           
$value->handlers = array_merge($value->handlers, $handlers);
        } else {
           
// Resolve the handlers when the forwarded promise is resolved.
           
$value->then(
                static function (
$value) use ($handlers) {
                    foreach (
$handlers as $handler) {
                       
self::callHandler(1, $value, $handler);
                    }
                },
                static function (
$reason) use ($handlers) {
                    foreach (
$handlers as $handler) {
                       
self::callHandler(2, $reason, $handler);
                    }
                }
            );
        }
    }

   
/**
     * Call a stack of handlers using a specific callback index and value.
     *
     * @param int $index 1 (resolve) or 2 (reject).
     * @param mixed $value Value to pass to the callback.
     * @param array $handler Array of handler data (promise and callbacks).
     *
     * @return array Returns the next group to resolve.
     */
   
private static function callHandler($index, $value, array $handler)
    {
       
/** @var PromiseInterface $promise */
       
$promise = $handler[0];

       
// The promise may have been cancelled or resolved before placing
        // this thunk in the queue.
       
if ($promise->getState() !== self::PENDING) {
            return;
        }

        try {
            if (isset(
$handler[$index])) {
               
$promise->resolve($handler[$index]($value));
            } elseif (
$index === 1) {
               
// Forward resolution values as-is.
               
$promise->resolve($value);
            } else {
               
// Forward rejections down the chain.
               
$promise->reject($value);
            }
        } catch (\
Exception $reason) {
           
$promise->reject($reason);
        }
    }

    private function
waitIfPending()
    {
        if (
$this->state !== self::PENDING) {
            return;
        } elseif (
$this->waitFn) {
           
$this->invokeWaitFn();
        } elseif (
$this->waitList) {
           
$this->invokeWaitList();
        } else {
           
// If there's not wait function, then reject the promise.
           
$this->reject('Cannot wait on a promise that has '
               
. 'no internal wait function. You must provide a wait '
               
. 'function when constructing the promise to be able to '
               
. 'wait on a promise.');
        }

       
queue()->run();

        if (
$this->state === self::PENDING) {
           
$this->reject('Invoking the wait callback did not resolve the promise');
        }
    }

    private function
invokeWaitFn()
    {
        try {
           
$wfn = $this->waitFn;
           
$this->waitFn = null;
           
$wfn(true);
        } catch (\
Exception $reason) {
            if (
$this->state === self::PENDING) {
               
// The promise has not been resolved yet, so reject the promise
                // with the exception.
               
$this->reject($reason);
            } else {
               
// The promise was already resolved, so there's a problem in
                // the application.
               
throw $reason;
            }
        }
    }

    private function
invokeWaitList()
    {
       
$waitList = $this->waitList;
       
$this->waitList = null;

        foreach (
$waitList as $result) {
           
descend:
           
$result->waitIfPending();
            if (
$result->result instanceof Promise) {
               
$result = $result->result;
                goto
descend;
            }
        }
    }
}