1 files changed, 45 insertions, 0 deletions
diff --git a/vespalib/src/vespa/vespalib/util/retain_guard.h b/vespalib/src/vespa/vespalib/util/retain_guard.h
new file mode 100644
index 00000000000..090f3ce75cf
--- /dev/null
+++ b/vespalib/src/vespa/vespalib/util/retain_guard.h
@@ -0,0 +1,45 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#pragma once
+
+#include "monitored_refcount.h"
+
+namespace vespalib {
+
+/*
+ * Class containing a reference to a monitored reference count,
+ * intended to block teardown of the class owning the monitored
+ * reference count.
+ */
+class RetainGuard {
+public:
+    RetainGuard(MonitoredRefCount & refCount) noexcept
+        : _refCount(&refCount)
+    {
+        _refCount->retain();
+    }
+    RetainGuard(const RetainGuard & rhs) = delete;
+    RetainGuard & operator=(const RetainGuard & rhs) = delete;
+    RetainGuard(RetainGuard && rhs) noexcept
+        : _refCount(rhs._refCount)
+    {
+        rhs._refCount = nullptr;
+    }
+    RetainGuard & operator=(RetainGuard && rhs) noexcept {
+        release();
+        _refCount = rhs._refCount;
+        rhs._refCount = nullptr;
+        return *this;
+    }
+    ~RetainGuard() { release(); }
+private:
+    void release() noexcept{
+        if (_refCount != nullptr) {
+            _refCount->release();
+            _refCount = nullptr;
+        }
+    }
+    MonitoredRefCount * _refCount;
+};
+
+}