Create initial BMC Item Updater

This is the initial BMC Item Updater.

Change-Id: I1c4f8ec94d7d35a0e03a363007b79414b20058ac
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/item_updater.hpp b/item_updater.hpp
new file mode 100644
index 0000000..1a36226
--- /dev/null
+++ b/item_updater.hpp
@@ -0,0 +1,69 @@
+#pragma once
+
+#include <sdbusplus/server.hpp>
+#include "activation.hpp"
+
+namespace phosphor
+{
+namespace software
+{
+namespace updater
+{
+
+/** @class ItemUpdater
+ *  @brief Manages the activation of the BMC version items.
+ */
+class ItemUpdater
+{
+    public:
+        ItemUpdater() = delete;
+        ~ItemUpdater() = default;
+        ItemUpdater(const ItemUpdater&) = delete;
+        ItemUpdater& operator=(const ItemUpdater&) = delete;
+        ItemUpdater(ItemUpdater&&) = delete;
+        ItemUpdater& operator=(ItemUpdater&&) = delete;
+
+        /** @brief Constructs ItemUpdater
+         *
+         * @param[in] bus    - The Dbus bus object
+         */
+        ItemUpdater(sdbusplus::bus::bus& bus) :
+                    bus(bus),
+                    versionMatch(
+                            bus,
+                           "type='signal',"
+                           "member='InterfacesAdded',"
+                           "path='/xyz/openbmc_project/software',"
+                           "interface='org.freedesktop.DBus.ObjectManager'",
+                            createActivation,
+                            this) {};
+
+    private:
+        /** @brief Callback function for Software.Version match.
+         *  @details Creates an Activation dbus object.
+         *
+         * @param[in]  msg       - Data associated with subscribed signal
+         * @param[in]  userData  - Pointer to this object instance
+         * @param[out] retError  - Required param
+         */
+        static int createActivation(sd_bus_message* msg,
+                                    void* userData,
+                                    sd_bus_error* retError);
+
+        /** @brief Persistent sdbusplus DBus bus connection. */
+        sdbusplus::bus::bus& bus;
+
+        /** @brief Persistent map of Activation dbus objects and their
+          * version id */
+        std::map<std::string, std::unique_ptr<Activation>> activations;
+
+        /** @brief sdbusplus signal match for Software.Version */
+        sdbusplus::server::match::match versionMatch;
+
+};
+
+
+
+} // namespace updater
+} // namespace software
+} // namespace phosphor