Enable setting log levels in DDS implementation (#124)

* Add rmw_log_level_t enum to enable setting log levels for the lowlevel DDS api's

* This patch enables support for three basic log levels
* There needs an API inside the DDS specific rmw implementation i.e
  rmw_fastrtps/rmw_opensplice etc to convert the enum to DDS specific variable

Signed-off-by: Sriram Raghunathan <sriram.max@gmail.com>

* Update changes based on github discussion based on

#124 (comment)

Using rcutils based log level, mapping them onto rmw specific
ones.

Signed-off-by: Sriram Raghunathan <sriram.max@gmail.com>

* Minor changes to existing code. Fix comment consistency and spacing consistency.

Signed-off-by: Sriram Raghunathan <sriram.max@gmail.com>

* Change variable name for consistency

Signed-off-by: Sriram Raghunathan <rsriram7@visteon.com>

* Add, rmw_log_set_severity API to rmw.h. This follows the set of
patches across ros2 sources for setting log levels inside DDS
implementation

Signed-off-by: Sriram Raghunathan <sriram.max@gmail.com>

* Remove pointer to variable severity, from the github discussions it was'nt needed

Signed-off-by: Sriram Raghunathan <sriram.max@gmail.com>

* Fix enum declaration errors

Signed-off-by: Sriram Raghunathan <sriram.max@gmail.com>

* Fix code styling issues

rmw/include/rmw/rmw.h

@@ -410,6 +410,11 @@ rmw_service_server_is_available(
   const rmw_client_t * client,
   bool * is_available);
 
+RMW_PUBLIC
+RMW_WARN_UNUSED
+rmw_ret_t
+rmw_set_log_severity(rmw_log_severity_t severity);
+
 #if __cplusplus
 }
 #endif

rmw/include/rmw/types.h

@@ -24,6 +24,8 @@ extern "C"
 #include <stddef.h>
 #include <stdint.h>
 
+// map rcutils specific log levels to rmw speicfic type
+#include <rcutils/logging.h>
 #include "rmw/visibility_control.h"
 
 typedef int rmw_ret_t;
@@ -228,6 +230,17 @@ typedef struct RMW_PUBLIC_TYPE rmw_message_info_t
 
 enum {RMW_QOS_POLICY_DEPTH_SYSTEM_DEFAULT = 0};
 
+// Type mapping of rcutil log severity types to
+// rmw specific types.
+typedef enum RWM_PUBLIC_TYPE
+{
+  RMW_LOG_SEVERITY_DEBUG = RCUTILS_LOG_SEVERITY_DEBUG,
+  RMW_LOG_SEVERITY_INFO = RCUTILS_LOG_SEVERITY_INFO,
+  RMW_LOG_SEVERITY_WARN = RCUTILS_LOG_SEVERITY_WARN,
+  RMW_LOG_SEVERITY_ERROR = RCUTILS_LOG_SEVERITY_ERROR,
+  RMW_LOG_SEVERITY_FATAL = RCUTILS_LOG_SEVERITY_FATAL
+} rmw_log_severity_t;
+
 #if __cplusplus
 }
 #endif