Initial Commit

dependencies/amphp/sync/src/LocalKeyedMutex.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace WP_Ultimo\Dependencies\Amp\Sync;
+
+use WP_Ultimo\Dependencies\Amp\Promise;
+use function WP_Ultimo\Dependencies\Amp\call;
+final class LocalKeyedMutex implements KeyedMutex
+{
+    /** @var LocalMutex[] */
+    private $mutex = [];
+    /** @var int[] */
+    private $locks = [];
+    public function acquire(string $key) : Promise
+    {
+        if (!isset($this->mutex[$key])) {
+            $this->mutex[$key] = new LocalMutex();
+            $this->locks[$key] = 0;
+        }
+        return call(function () use($key) {
+            $this->locks[$key]++;
+            /** @var Lock $lock */
+            $lock = (yield $this->mutex[$key]->acquire());
+            return new Lock(0, function () use($lock, $key) {
+                if (--$this->locks[$key] === 0) {
+                    unset($this->mutex[$key], $this->locks[$key]);
+                }
+                $lock->release();
+            });
+        });
+    }
+}