Commit inicial con archivos existentes

vendor/react/promise/src/CancellationQueue.php

@@ -0,0 +1,55 @@
+<?php
+
+namespace React\Promise;
+
+class CancellationQueue
+{
+    private $started = false;
+    private $queue = [];
+
+    public function __invoke()
+    {
+        if ($this->started) {
+            return;
+        }
+
+        $this->started = true;
+        $this->drain();
+    }
+
+    public function enqueue($cancellable)
+    {
+        if (!\is_object($cancellable) || !\method_exists($cancellable, 'then') || !\method_exists($cancellable, 'cancel')) {
+            return;
+        }
+
+        $length = \array_push($this->queue, $cancellable);
+
+        if ($this->started && 1 === $length) {
+            $this->drain();
+        }
+    }
+
+    private function drain()
+    {
+        for ($i = key($this->queue); isset($this->queue[$i]); $i++) {
+            $cancellable = $this->queue[$i];
+
+            $exception = null;
+
+            try {
+                $cancellable->cancel();
+            } catch (\Throwable $exception) {
+            } catch (\Exception $exception) {
+            }
+
+            unset($this->queue[$i]);
+
+            if ($exception) {
+                throw $exception;
+            }
+        }
+
+        $this->queue = [];
+    }
+}