* use \React\Promise\Deferred; * * $exec = new pq\Query\AsyncExecutor(new pq\Connection); * $exec->setCallbacks( * # init context * function() { * return new Deferred; * }, * # done * function(Deferred $context, $result) { * $context->resolver()->resolve($result); * }, * # then * function(Deferred $context, callable $cb) { * return $context->then($cb); * }); * $exec->execute($queryWriter, function($result){}); * * * Example with amphp: *


	 * use amp\Future;
	 * use function amp\reactor;
	 * 
	 * $exec = new pq\Query\AsyncExecutor(new pq\Connection);
	 * $exec->setCallbacks(
	 * # init context
	 * function() {
	 *		return new Future(reactor());
	 * },
	 * # done
	 * function(Future $context, $result) {
	 *		$context->succeed($result);
	 * },
	 * # then
	 * function(Future $context, callable $cb) {
	 *		return $context->when(function ($error, $result) {
	 *			$cb($result);
	 *		});
	 * });
	 * $exec->execute($queryWriter, function($result){});
	 *

* * @param callable $init context initializer as function() * @param callable $done result receiver as function($context, $result) * @param callable $then callback queue as function($context, $callback) */ function setCallbacks(callable $init, callable $done, callable $then) { $this->init = $init; $this->done = $done; $this->then = $then; } /** * Get (promise) callbacks previously set * @return array(callable) */ function getCallbacks() { return array($this->init, $this->done, $this->then); } /** * Prepare (promise) callbacks * @param callable $callback * @return array($context, $resolver) */ protected function prepareCallback(callable $callback/*, ... */) { list($init, $done, $then) = $this->getCallbacks(); $context = $init(); foreach (func_get_args() as $cb) { $then($context, $cb); } $then($context, $callback); return array($context, function($result) use ($context, $done) { $done($context, $result); }); } /** * Result callback * @param \pq\Result $result */ protected function receiveResult(\pq\Result $result) { $this->result = $result; $this->notify(); } /** * Execute the query asynchronously through \pq\Connection::execParamsAsync() * @param \pq\Query\WriterInterface $query * @param callable $callback result callback * @return mixed context created by the init callback */ function execute(WriterInterface $query, callable $callback) { $this->result = null; $this->query = $query; $this->notify(); list($context, $resolver) = $this->prepareCallback( array($this, "receiveResult"), $callback); $this->getConnection()->execParamsAsync($query, $query->getParams(), $query->getTypes(), $resolver); return $context; } }