vendor/overblog/graphql-bundle/src/Relay/Connection/Paginator.php line 69

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  1. <?php
  3. declare(strict_types=1);
  5. namespace Overblog\GraphQLBundle\Relay\Connection;
  7. use GraphQL\Executor\Promise\Promise;
  8. use Overblog\GraphQLBundle\Definition\ArgumentInterface;
  9. use Overblog\GraphQLBundle\Relay\Connection\Output\Connection;
  10. use function call_user_func;
  11. use function call_user_func_array;
  12. use function count;
  13. use function is_callable;
  14. use function is_numeric;
  15. use function max;
  17. class Paginator
  18. {
  19.     public const MODE_REGULAR = false;
  20.     public const MODE_PROMISE = true;
  22.     private bool $promise;
  23.     private int $totalCount;
  24.     private ConnectionBuilder $connectionBuilder;
  26.     /** @var callable */
  27.     private $fetcher;
  29.     public function __construct(callable $fetcher, bool $promise = self::MODE_REGULAR, ConnectionBuilder $connectionBuilder = null)
  30.     {
  31.         $this->fetcher = $fetcher;
  32.         $this->promise = $promise;
  33.         $this->connectionBuilder = $connectionBuilder ?? new ConnectionBuilder();
  34.     }
  36.     /**
  37.      * @param int|callable $total
  38.      *
  39.      * @return Connection|Promise A connection or a promise
  40.      */
  41.     public function backward(ArgumentInterface $args, $total, array $callableArgs = [])
  42.     {
  43.         $total = $this->computeTotalCount($total, $callableArgs);
  44.         $limit = $args['last'] ?? null;
  45.         $before = $args['before'] ?? null;
  46.         $offset = max(0, $this->connectionBuilder->getOffsetWithDefault($before, $total) - $limit);
  48.         $entities = call_user_func($this->fetcher, $offset, $limit);
  50.         return $this->handleEntities($entities, function ($entities) use ($args, $offset, $total) {
  51.             return $this->connectionBuilder->connectionFromArraySlice($entities, $args, [
  52.                 'sliceStart' => $offset,
  53.                 'arrayLength' => $total,
  54.             ]);
  55.         });
  56.     }
  58.     /**
  59.      * @return Connection|Promise A connection or a promise
  60.      */
  61.     public function forward(ArgumentInterface $args)
  62.     {
  63.         $limit = $args['first'] ?? null;
  64.         $after = $args['after'] ?? null;
  65.         $offset = $this->connectionBuilder->getOffsetWithDefault($after, 0);
  67.         // If we don't have a cursor or if it's not valid, then we must not use the slice method
  68.         if (!is_numeric($this->connectionBuilder->cursorToOffset($after)) || !$after) {
  69.             $entities = call_user_func($this->fetcher, $offset, $limit ? $limit + 1 : $limit);
  71.             return $this->handleEntities($entities, fn ($entities) => $this->connectionBuilder->connectionFromArray($entities, $args));
  72.         } else {
  73.             $entities = call_user_func($this->fetcher, $offset, $limit ? $limit + 2 : $limit);
  75.             return $this->handleEntities($entities, function ($entities) use ($args, $offset) {
  76.                 return $this->connectionBuilder->connectionFromArraySlice($entities, $args, [
  77.                     'sliceStart' => $offset,
  78.                     'arrayLength' => $offset + count($entities),
  79.                 ]);
  80.             });
  81.         }
  82.     }
  84.     /**
  85.      * @param int|callable $total
  86.      *
  87.      * @return Connection|Promise A connection or a promise
  88.      */
  89.     public function auto(ArgumentInterface $args, $total, array $callableArgs = [])
  90.     {
  91.         if (isset($args['last'])) {
  92.             $connection = $this->backward($args, $total, $callableArgs);
  93.         } else {
  94.             $connection = $this->forward($args);
  95.         }
  97.         if ($this->promise) {
  98.             /** @var Promise $connection */
  99.             return $connection->then(function (ConnectionInterface $connection) use ($total, $callableArgs) {
  100.                 $connection->setTotalCount($this->computeTotalCount($total, $callableArgs));
  102.                 return $connection;
  103.             });
  104.         } else {
  105.             /** @var Connection $connection */
  106.             $connection->setTotalCount($this->computeTotalCount($total, $callableArgs));
  108.             return $connection;
  109.         }
  110.     }
  112.     /**
  113.      * @param array<int, string>|Promise $entities An array of entities to paginate or a promise
  114.      *
  115.      * @return Connection|Promise A connection or a promise
  116.      */
  117.     private function handleEntities($entities, callable $callback)
  118.     {
  119.         if ($this->promise) {
  120.             /** @var Promise $entities */
  121.             return $entities->then($callback);
  122.         }
  124.         return $callback($entities);
  125.     }
  127.     /**
  128.      * @param int|callable $total
  129.      *
  130.      * @return int|mixed
  131.      */
  132.     private function computeTotalCount($total, array $callableArgs = [])
  133.     {
  134.         if (isset($this->totalCount)) {
  135.             return $this->totalCount;
  136.         }
  138.         $this->totalCount = is_callable($total) ? call_user_func_array($total, $callableArgs) : $total;
  140.         return $this->totalCount;
  141.     }
  142. }