/**
* Start crawling.
*
* @param int $chunk
*
* @return \GuzzleHttp\Promise\PromiseInterface
*/
public function start($chunk = 5)
{
$this->dispatchStart();
// We need to use a double loop of generators here, because
// if $chunk is greater than the number of items in the queue,
// the requestWorkerFn exits the generator loop before any new
// requests can be added by processing and cannot be restarted.
// The outer generator ($gen) restarts the processing in that case.
$gen = function () use($chunk) {
while ($this->queue->count() > 0) {
$inner = new EachPromise($this->getRequestWorkerFn(), ['concurrency' => $chunk]);
(yield $inner->promise());
}
};
$outer = new EachPromise($gen(), ['concurrency' => 1]);
$finish = function ($results) {
$this->dispatchFinish();
return $results;
};
return $outer->promise()->then($finish, $finish);
}
/**
* @return \GuzzleHttp\Promise\PromiseInterface
*/
public function promise()
{
return $this->each->promise();
}
public function testDoesNotCallNextOnIteratorUntilNeededWhenAsync()
{
$firstPromise = new Promise();
$pending = [$firstPromise];
$values = [$firstPromise];
$results = [];
$remaining = 9;
$iter = function () use(&$values) {
while ($value = array_pop($values)) {
(yield $value);
}
};
$each = new EachPromise($iter(), ['concurrency' => 1, 'fulfilled' => function ($r) use(&$results, &$values, &$remaining, &$pending) {
$results[] = $r;
if ($remaining-- > 0) {
$pending[] = $values[] = new Promise();
}
}]);
$i = 0;
$each->promise();
while ($promise = array_pop($pending)) {
$promise->resolve($i++);
P\queue()->run();
}
$this->assertEquals(range(0, 9), $results);
}
public function testRejectsAggregateWhenNextThrows()
{
$iter = function () {
(yield 'a');
throw new \Exception('Failure');
};
$each = new EachPromise($iter());
$p = $each->promise();
$e = null;
$received = null;
$p->then(null, function ($reason) use(&$e) {
$e = $reason;
});
P\queue()->run();
$this->assertInstanceOf('Exception', $e);
$this->assertEquals('Failure', $e->getMessage());
}
public function testMutexPreventsGeneratorRecursion()
{
$results = $promises = [];
for ($i = 0; $i < 20; $i++) {
$p = $this->createSelfResolvingPromise($i);
$pending[] = $p;
$promises[] = $p;
}
$iter = function () use(&$promises, &$pending) {
foreach ($promises as $promise) {
// Resolve a promises, which will trigger the then() function,
// which would cause the EachPromise to try to add more
// promises to the queue. Without a lock, this would trigger
// a "Cannot resume an already running generator" fatal error.
if ($p = array_pop($pending)) {
$p->wait();
}
(yield $promise);
}
};
$each = new EachPromise($iter(), ['concurrency' => 5, 'fulfilled' => function ($r) use(&$results, &$pending) {
$results[] = $r;
}]);
$each->promise()->wait();
$this->assertCount(20, $results);
}