param: add a px4_parameters_public.h.jinja template

Generates an enum with all params & additional type information for static
type checking

The generated public param header is required to build the modules using
the new BlockParam classes.

CMakeLists.txt

@@ -335,7 +335,7 @@ px4_join(OUT CMAKE_EXE_LINKER_FLAGS LIST "${CMAKE_EXE_LINKER_FLAGS};${exe_linker
 px4_join(OUT CMAKE_C_FLAGS LIST "${CMAKE_C_FLAGS};${c_flags};${optimization_flags}" GLUE " ")
 px4_join(OUT CMAKE_CXX_FLAGS LIST "${CMAKE_CXX_FLAGS};${cxx_flags};${optimization_flags}" GLUE " ")
 
-include_directories(${include_dirs})
+include_directories(${include_dirs} ${CMAKE_CURRENT_BINARY_DIR}/src/modules/systemlib/param)
 link_directories(${link_dirs})
 add_definitions(${definitions})
 

src/modules/systemlib/param/CMakeLists.txt

@@ -98,8 +98,8 @@ add_custom_command(OUTPUT ${parameters_xml}
 )
 add_custom_target(parameters_xml DEPENDS ${parameters_xml})
 
-# generate px4_parameters.c and px4_parameters.h
-add_custom_command(OUTPUT px4_parameters.c px4_parameters.h
+# generate px4_parameters.c and px4_parameters{,_public}.h
+add_custom_command(OUTPUT px4_parameters.c px4_parameters.h px4_parameters_public.h
 	COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/px_generate_params.py
 		--xml ${parameters_xml} --dest ${CMAKE_CURRENT_BINARY_DIR}
 	DEPENDS
@@ -107,8 +107,12 @@ add_custom_command(OUTPUT px4_parameters.c px4_parameters.h
 		px_generate_params.py
 		templates/px4_parameters.c.jinja
 		templates/px4_parameters.h.jinja
+		templates/px4_parameters_public.h.jinja
 	)
 
+add_custom_target(parameter_headers DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/px4_parameters_public.h)
+add_dependencies(prebuild_targets parameter_headers)
+
 px4_add_module(
 	MODULE modules__systemlib__param
 	COMPILE_FLAGS

src/modules/systemlib/param/px_generate_params.py

@@ -40,6 +40,7 @@ def generate(xml_file, dest='.'):
 
     template_files = [
         'px4_parameters.h.jinja',
+        'px4_parameters_public.h.jinja',
         'px4_parameters.c.jinja',
     ]
     for template_file in template_files:

src/modules/systemlib/param/templates/px4_parameters_public.h.jinja

+{# jinja syntax: http://jinja.pocoo.org/docs/2.9/templates/ #}
+#include <stdint.h>
+#include <systemlib/param/param.h>
+
+// DO NOT EDIT
+// This file is autogenerated from parameters.xml
+
+
+#ifdef	__cplusplus
+
+namespace px4 { {# wrap the enum in a namespace, otherwise we get shadowing errors for MAV_TYPE #}
+
+/// Enum with all parameters
+enum class params {
+	{# enums are guaranteed to start with 0 (if the value for the first is not
+	   specified), and then incremented by 1 #}
+{%- for param in params %}
+	{{ param.attrib["name"] }},
+{%- endfor %}
+	
+	_COUNT
+};
+
+// All parameter types
+{# (px4_parameters is marked as extern, so we cannot use it as constexpr) #}
+static const constexpr int param_types_array[] =  {
+{%- for param in params %}
+	PARAM_TYPE_{{ param.attrib["type"] }}, // {{ param.attrib["name"] }}
+{%- endfor %}
+};
+
+
+} // namespace px4
+
+
+#endif /* __cplusplus */
+