1 files changed, 71 insertions, 0 deletions
diff --git a/vendor/open-telemetry/sdk/Metrics/StalenessHandler/DelayedStalenessHandler.php b/vendor/open-telemetry/sdk/Metrics/StalenessHandler/DelayedStalenessHandler.php
new file mode 100644
index 000000000..66b271018
--- /dev/null
+++ b/vendor/open-telemetry/sdk/Metrics/StalenessHandler/DelayedStalenessHandler.php
@@ -0,0 +1,71 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\SDK\Metrics\StalenessHandler;
+
+use function assert;
+use Closure;
+use OpenTelemetry\SDK\Metrics\ReferenceCounterInterface;
+use OpenTelemetry\SDK\Metrics\StalenessHandlerInterface;
+
+/**
+ * @internal
+ */
+final class DelayedStalenessHandler implements StalenessHandlerInterface, ReferenceCounterInterface
+{
+    private Closure $stale;
+    private Closure $freshen;
+
+    /** @var Closure[]|null */
+    private ?array $onStale = [];
+    private int $count = 0;
+
+    public function __construct(Closure $stale, Closure $freshen)
+    {
+        $this->stale = $stale;
+        $this->freshen = $freshen;
+    }
+
+    public function acquire(bool $persistent = false): void
+    {
+        if ($this->count === 0) {
+            ($this->freshen)($this);
+        }
+
+        $this->count++;
+
+        if ($persistent) {
+            $this->onStale = null;
+        }
+    }
+
+    public function release(): void
+    {
+        if (--$this->count || $this->onStale === null) {
+            return;
+        }
+
+        ($this->stale)($this);
+    }
+
+    public function onStale(Closure $callback): void
+    {
+        if ($this->onStale === null) {
+            return;
+        }
+
+        $this->onStale[] = $callback;
+    }
+
+    public function triggerStale(): void
+    {
+        assert($this->onStale !== null);
+
+        $callbacks = $this->onStale;
+        $this->onStale = [];
+        foreach ($callbacks as $callback) {
+            $callback();
+        }
+    }
+}