slot: add binding class for sd_bus_slot

Change-Id: Ib092ec3fd22be1d2a9755457235aba81acb606a1
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>

1 files changed, 69 insertions, 0 deletions

diff --git a/sdbusplus/slot.hpp b/sdbusplus/slot.hpp
new file mode 100644
index 0000000..039f520
--- /dev/null
+++ b/sdbusplus/slot.hpp
@@ -0,0 +1,69 @@
+#pragma once
+
+#include <memory>
+#include <systemd/sd-bus.h>
+
+namespace sdbusplus
+{
+
+namespace slot
+{
+
+using slotp_t = sd_bus_slot*;
+class slot;
+
+namespace details
+{
+
+/** @brief unique_ptr functor to release a slot reference. */
+struct SlotDeleter
+{
+    void operator()(slotp_t ptr) const
+    {
+        sd_bus_slot_unref(ptr);
+    }
+};
+
+using slot = std::unique_ptr<sd_bus_slot, SlotDeleter>;
+
+} // namespace details
+
+/** @class slot
+ *  @brief Provides C++ holder for sd_bus_slot instances.
+ */
+struct slot
+{
+        /* Define all of the basic class operations:
+         *     Not allowed:
+         *         - Default constructor to avoid nullptrs.
+         *         - Copy operations due to internal unique_ptr.
+         *     Allowed:
+         *         - Move operations.
+         *         - Destructor.
+         */
+    slot() = delete;
+    slot(const slot&) = delete;
+    slot& operator=(const slot&) = delete;
+    slot(slot&&) = default;
+    slot& operator=(slot&&) = default;
+    ~slot() = default;
+
+    /** @brief Conversion constructor for 'slotp_t'.
+     *
+     *  Takes ownership of the slot-pointer and releases it when done.
+     */
+    explicit slot(slotp_t s) : _slot(s) {}
+
+    /** @brief Release ownership of the stored slot-pointer. */
+    slotp_t release() { return _slot.release(); }
+
+    /** @brief Check if slot contains a real pointer. (non-nullptr). */
+    explicit operator bool() const { return bool(_slot); }
+
+    private:
+        details::slot _slot;
+
+};
+
+} // namespace slot
+} // namespace sdbusplus