Initial Commit

dependencies/amphp/sync/src/LocalMutex.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace WP_Ultimo\Dependencies\Amp\Sync;
+
+use WP_Ultimo\Dependencies\Amp\CallableMaker;
+use WP_Ultimo\Dependencies\Amp\Deferred;
+use WP_Ultimo\Dependencies\Amp\Promise;
+use WP_Ultimo\Dependencies\Amp\Success;
+class LocalMutex implements Mutex
+{
+    use CallableMaker;
+    // kept for BC only
+    /** @var bool */
+    private $locked = \false;
+    /** @var Deferred[] */
+    private $queue = [];
+    /** {@inheritdoc} */
+    public function acquire() : Promise
+    {
+        if (!$this->locked) {
+            $this->locked = \true;
+            return new Success(new Lock(0, \Closure::fromCallable([$this, 'release'])));
+        }
+        $this->queue[] = $deferred = new Deferred();
+        return $deferred->promise();
+    }
+    private function release() : void
+    {
+        if (!empty($this->queue)) {
+            $deferred = \array_shift($this->queue);
+            $deferred->resolve(new Lock(0, \Closure::fromCallable([$this, 'release'])));
+            return;
+        }
+        $this->locked = \false;
+    }
+}