send PLDM event msg when state sensor changes

Add the D-Bus to event handler interface to listen all of the state
sensor PDRs and pldm should be able to send up a PLDM event msg when a
D-Bus property changes. the PlatformEventMessage command format is
defined in Table 15 in DSP0248 v1.2.0.

Tested: test with JSON
https://gist.github.com/lxwinspur/6a40abea7330c25e4d49826e890c4be9
The sendEventMsg method is successfully called and the corresponding
message is successfully sent when the D-Bus property value of the sensor
status changes.
print requestMsg Data: 80 02 0a 01 00 00 01 00 01 00 00 00(when calling
sendEventMsg method)

Signed-off-by: George Liu <liuxiwei@inspur.com>
Change-Id: I9b6d5c1403bfcaa00dbbf478f7d797cc4a40f20d
diff --git a/host-bmc/dbus_to_event_handler.hpp b/host-bmc/dbus_to_event_handler.hpp
new file mode 100644
index 0000000..add5c2d
--- /dev/null
+++ b/host-bmc/dbus_to_event_handler.hpp
@@ -0,0 +1,85 @@
+#pragma once
+
+#include "libpldm/platform.h"
+
+#include "libpldmresponder/pdr_utils.hpp"
+#include "pldmd/dbus_impl_requester.hpp"
+
+#include <map>
+
+using namespace pldm::dbus_api;
+using namespace pldm::responder;
+
+namespace pldm
+{
+
+using SensorId = uint16_t;
+using DbusObjMaps =
+    std::map<SensorId,
+             std::tuple<pdr_utils::DbusMappings, pdr_utils::DbusValMaps>>;
+using sensorEvent =
+    std::function<void(SensorId sensorId, const DbusObjMaps& dbusMaps)>;
+
+namespace state_sensor
+{
+/** @class DbusToPLDMEvent
+ *  @brief This class can listen to the state sensor PDRs and send PLDM event
+ *         msg when a D-Bus property changes
+ */
+class DbusToPLDMEvent
+{
+  public:
+    DbusToPLDMEvent() = delete;
+    DbusToPLDMEvent(const DbusToPLDMEvent&) = delete;
+    DbusToPLDMEvent(DbusToPLDMEvent&&) = delete;
+    DbusToPLDMEvent& operator=(const DbusToPLDMEvent&) = delete;
+    DbusToPLDMEvent& operator=(DbusToPLDMEvent&&) = delete;
+    ~DbusToPLDMEvent() = default;
+
+    /** @brief Constructor
+     *  @param[in] mctp_fd - fd of MCTP communications socket
+     *  @param[in] mctp_eid - MCTP EID of host firmware
+     *  @param[in] requester - reference to Requester object
+     */
+    explicit DbusToPLDMEvent(int mctp_fd, uint8_t mctp_eid,
+                             Requester& requester);
+
+  public:
+    /** @brief Listen all of the state sensor PDRs
+     *  @param[in] repo - pdr utils repo object
+     *  @param[in] dbusMaps - The map of D-Bus mapping and value
+     */
+    void listenSensorEvent(const pdr_utils::Repo& repo,
+                           const DbusObjMaps& dbusMaps);
+
+  private:
+    /** @brief Send state sensor event msg when a D-Bus property changes
+     *  @param[in] sensorId - sensor id
+     */
+    void sendStateSensorEvent(SensorId sensorId, const DbusObjMaps& dbusMaps);
+
+    /** @brief Send all of sensor event
+     *  @param[in] eventType - PLDM Event types
+     *  @param[in] eventDataVec - std::vector, contains send event data
+     */
+    void sendEventMsg(uint8_t eventType,
+                      const std::vector<uint8_t>& eventDataVec);
+
+    /** @brief fd of MCTP communications socket */
+    int mctp_fd;
+
+    /** @brief MCTP EID of host firmware */
+    uint8_t mctp_eid;
+
+    /** @brief reference to Requester object, primarily used to access API to
+     *  obtain PLDM instance id.
+     */
+    Requester& requester;
+
+    /** @brief D-Bus property changed signal match */
+    std::vector<std::unique_ptr<sdbusplus::bus::match::match>>
+        stateSensorMatchs;
+};
+
+} // namespace state_sensor
+} // namespace pldm