LockingMiddleware.php
72 lines
| 1 | <?php |
| 2 | |
| 3 | namespace League\Tactician\Plugins; |
| 4 | |
| 5 | use League\Tactician\Middleware; |
| 6 | |
| 7 | /** |
| 8 | * If another command is already being executed, locks the command bus and |
| 9 | * queues the new incoming commands until the first has completed. |
| 10 | */ |
| 11 | class LockingMiddleware implements Middleware |
| 12 | { |
| 13 | /** |
| 14 | * @var bool |
| 15 | */ |
| 16 | private $isExecuting; |
| 17 | |
| 18 | /** |
| 19 | * @var callable[] |
| 20 | */ |
| 21 | private $queue = []; |
| 22 | |
| 23 | /** |
| 24 | * Execute the given command... after other running commands are complete. |
| 25 | * |
| 26 | * @param object $command |
| 27 | * @param callable $next |
| 28 | * |
| 29 | * @throws \Exception |
| 30 | * |
| 31 | * @return mixed|void |
| 32 | */ |
| 33 | public function execute($command, callable $next) |
| 34 | { |
| 35 | $this->queue[] = function () use ($command, $next) { |
| 36 | return $next($command); |
| 37 | }; |
| 38 | |
| 39 | if ($this->isExecuting) { |
| 40 | return; |
| 41 | } |
| 42 | $this->isExecuting = true; |
| 43 | |
| 44 | try { |
| 45 | $returnValue = $this->executeQueuedJobs(); |
| 46 | } catch (\Exception $e) { |
| 47 | $this->isExecuting = false; |
| 48 | $this->queue = []; |
| 49 | throw $e; |
| 50 | } |
| 51 | |
| 52 | $this->isExecuting = false; |
| 53 | return $returnValue; |
| 54 | } |
| 55 | |
| 56 | /** |
| 57 | * Process any pending commands in the queue. If multiple, jobs are in the |
| 58 | * queue, only the first return value is given back. |
| 59 | * |
| 60 | * @return mixed |
| 61 | */ |
| 62 | protected function executeQueuedJobs() |
| 63 | { |
| 64 | $returnValues = []; |
| 65 | while ($resumeCommand = array_shift($this->queue)) { |
| 66 | $returnValues[] = $resumeCommand(); |
| 67 | } |
| 68 | |
| 69 | return array_shift($returnValues); |
| 70 | } |
| 71 | } |
| 72 |