Fix cross-compilation support for gz-msg10 (#392)

Signed-off-by: Silvio Traversaro <[email protected]>
Co-authored-by: Michael Carroll <[email protected]>

CMakeLists.txt

@@ -25,34 +25,49 @@ gz_configure_project(VERSION_SUFFIX
 #============================================================================
 
 # Cross-compilation related options
-# In a cross-compilation scenario, it is possible that the gz_msgs_gen
+# In a cross-compilation scenario, it is possible that the 
+# ${PROJECT_NAME}_protoc_plugin
 # generator compiled for the target machine cannot be used to generate
-# the C++ code corresponding to the .proto definition. For this scenario,
-# the following two options can be used as follows.
+# the C++ code corresponding to the .proto definition.
+# Similarly, it is possible that Python3::Interpreter and protobuf::protoc
+# found via find_package are not executable that can be run during the build.
+# To avoid, that the following options can be used as follows.
 # First of all, gz-msgs is compiled targeting the host machine, and in the
-# build targeting the host, the INSTALL_GZ_MSGS_GEN_EXECUTABLE option is
-# enabled:
-# > cmake -DINSTALL_GZ_MSGS_GEN_EXECUTABLE:BOOL=ON ..
-# ensuring that the gz_msgs_gen is installed in
-# <host_install_prefix>/bin/gz_msgs_gen . Then, the same version of gz-msgs
+# build targeting the host, ensuring that the ${PROJECT_NAME}_protoc_plugin
+# is installed in <host_install_prefix>/bin/${PROJECT_NAME}_protoc_plugin . 
+# Then, the same version of gz-msgs
 # can be cross-compiled, and in the cross-compilation build the location of the
-# host gz_msgs_gen is specified via the GZ_MSGS_GEN_EXECUTABLE
-# CMake cache variable:
-# > cmake -GZ_MSGS_GEN_EXECUTABLE=<host_install_prefix>/bin/gz_msgs_gen ..
+# host gz_msgs_gen is specified via the GZ_MSGS_GEN_EXECUTABLE CMake option.
+# Similarly to gz-msgs, also a copy of protoc and of the Python interpreter need
+# to be installed in the host at <host_install_prefix>/bin, and they can be passed
+# to the build appropriate CMake options:
+# > cmake -Dgz-msgs<MajVer>_PROTO_GENERATOR_PLUGIN=gz-msgs<MajVer>_protoc_plugin
+# > -Dgz-msgs<MajVer>_PROTOC_EXECUTABLE=<host_install_prefix>/bin/protoc
+# > -Dgz-msgs<MajVer>_PYTHON_INTERPRETER=<host_install_prefix>/bin/python 
+# > ..
+# In case the gz-msgs CMake functions are used also in downstream projects, 
+# the same variables can be passed when configuring the downsream projects.
 
-option(
- INSTALL_GZ_MSGS_GEN_EXECUTABLE
- "Install the gz_msgs_gen executable."
- OFF)
+set(
+ ${PROJECT_NAME}_PROTO_GENERATOR_PLUGIN
+ "${PROJECT_NAME}_protoc_plugin"
+ CACHE STRING
+ "gz_msgs_gen executable used in the gz-msgs CMake functions.")
+mark_as_advanced(${PROJECT_NAME}_PROTO_GENERATOR_PLUGIN)
 
-mark_as_advanced(INSTALL_GZ_MSGS_GEN_EXECUTABLE)
+set(
+ ${PROJECT_NAME}_PROTOC_EXECUTABLE
+ protobuf::protoc
+ CACHE STRING
+ "protoc target or executable used in the gz-msgs CMake functions.")
+mark_as_advanced(${PROJECT_NAME}_PROTOC_EXECUTABLE)
 
 set(
- GZ_MSGS_GEN_EXECUTABLE
- "$<TARGET_FILE:gz_msgs_gen>"
+ ${PROJECT_NAME}_PYTHON_INTERPRETER
+ Python3::Interpreter
  CACHE STRING
- "gz_msgs_gen executable used in the gz_msgs_protoc CMake function.")
-mark_as_advanced(GZ_MSGS_GEN_EXECUTABLE)
+ "python target or executable used in the gz-msgs CMake functions.")
+mark_as_advanced(${PROJECT_NAME}_PYTHON_INTERPRETER)
 
 # Python interfaces vars
 option(USE_SYSTEM_PATHS_FOR_PYTHON_INSTALLATION

cmake/gz_msgs_factory.cmake

@@ -6,7 +6,7 @@
 # One value arguments:
 # FACTORY_GEN_SCRIPT - Location of the factory generator script
 # PROTO_PACKAGE - Protobuf package the file belongs to (e.g. "gz.msgs")
-# PROTOC_EXEC - Path to protoc
+# PYTHON_INTERPRETER - Target or path to the Python interpreter to use to execute the generator script
 # OUTPUT_CPP_DIR - Path where C++ files are saved
 # OUTPUT_CPP_HH_VAR - A CMake variable name containing a list that the C++ headers should be appended to
 # OUTPUT_CPP_CC_VAR - A Cmake variable name containing a list that the C++ sources should be appended to
@@ -18,13 +18,19 @@ function(gz_msgs_factory)
  set(oneValueArgs
  FACTORY_GEN_SCRIPT
  PROTO_PACKAGE
+ PYTHON_INTERPRETER
  OUTPUT_CPP_DIR
  OUTPUT_CPP_HH_VAR
  OUTPUT_CPP_CC_VAR)
  set(multiValueArgs INPUT_PROTOS PROTO_PATH)
 
  cmake_parse_arguments(gz_msgs_factory "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
 
+ # Default values for optional parameters
+ if (NOT DEFINED gz_msgs_factory_PYTHON_INTERPRETER)
+ set(gz_msgs_factory_PYTHON_INTERPRETER Python3::Interpreter)
+ endif()
+
  _gz_msgs_proto_pkg_to_path(${gz_msgs_factory_PROTO_PACKAGE} proto_package_dir)
 
  set(output_header "${gz_msgs_factory_OUTPUT_CPP_DIR}/${proto_package_dir}/MessageTypes.hh")
@@ -57,7 +63,7 @@ function(gz_msgs_factory)
 
  add_custom_command(
  OUTPUT ${output_files}
- COMMAND Python3::Interpreter
+ COMMAND ${gz_msgs_factory_PYTHON_INTERPRETER}
  ARGS ${gz_msgs_factory_FACTORY_GEN_SCRIPT} ${GENERATE_ARGS}
  DEPENDS
  ${depends_index}

cmake/gz_msgs_generate.cmake

@@ -2,6 +2,7 @@
 # The implementation of gz_msgs_generate_messages
 # Options:
 # One value arguments:
+# PYTHON_INTERPRETER - Target or path to the python interpreter used
 # PROTO_PACKAGE - Protobuf package the file belongs to (e.g. "gz.msgs")
 # MSGS_GEN_SCRIPT - Location of the messge generator script
 # GZ_PROTOC_PLUGIN - Location of the gazebo generator plugin
@@ -20,6 +21,8 @@ function(gz_msgs_generate_messages_impl)
  set(options "")
  set(oneValueArgs
  # Inputs
+ PYTHON_INTERPRETER
+ PROTOC_EXEC
  PROTO_PACKAGE MSGS_GEN_SCRIPT GZ_PROTOC_PLUGIN FACTORY_GEN_SCRIPT PROTO_PATH
  DEPENDENCY_DESCRIPTIONS
  DLLEXPORT_DECL
@@ -33,6 +36,15 @@ function(gz_msgs_generate_messages_impl)
  set(multiValueArgs INPUT_PROTOS)
 
  cmake_parse_arguments(generate_messages "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+
+ # Default values for optional parameters
+ if (NOT DEFINED generate_messages_PYTHON_INTERPRETER)
+ set(generate_messages_PYTHON_INTERPRETER Python3::Interpreter)
+ endif()
+ if (NOT DEFINED generate_messages_PROTOC_EXEC)
+ set(generate_messages_PROTOC_EXEC protobuf::protoc)
+ endif()
+
  _gz_msgs_proto_pkg_to_string(${generate_messages_PROTO_PACKAGE} gen_dir)
  _gz_msgs_proto_pkg_to_path(${generate_messages_PROTO_PACKAGE} proto_package_dir)
  set(output_directory ${generate_messages_OUTPUT_DIRECTORY})
@@ -42,14 +54,16 @@ function(gz_msgs_generate_messages_impl)
 
  foreach(proto_file ${generate_messages_INPUT_PROTOS})
  gz_msgs_protoc(
+ PYTHON_INTERPRETER
+ ${generate_messages_PYTHON_INTERPRETER}
  MSGS_GEN_SCRIPT
  ${generate_messages_MSGS_GEN_SCRIPT}
  PROTO_PACKAGE
  ${generate_messages_PROTO_PACKAGE}
  INPUT_PROTO
  ${proto_file}
  PROTOC_EXEC
- protobuf::protoc
+ ${generate_messages_PROTOC_EXEC}
  GZ_PROTOC_PLUGIN
  ${generate_messages_GZ_PROTOC_PLUGIN}
  PROTO_PATH
@@ -81,6 +95,8 @@ function(gz_msgs_generate_messages_impl)
  endforeach()
 
  gz_msgs_factory(
+ PYTHON_INTERPRETER
+ ${generate_messages_PYTHON_INTERPRETER}
  FACTORY_GEN_SCRIPT
  ${generate_messages_FACTORY_GEN_SCRIPT}
  PROTO_PACKAGE
@@ -130,6 +146,7 @@ endfunction()
 ##################################################
 # Options:
 # One value arguments:
+# PROTOC_EXEC - protoc target or executable to use
 # PROTO_PATH - Base directory of the proto files
 # DEPENDENCY_DESCRIPTIONS - Variable containing all depedency description files
 # OUTPUT_DIRECTORY - Directory of output gz_desc file
@@ -140,6 +157,7 @@ function(gz_msgs_generate_desc_impl)
  set(options "")
  set(oneValueArgs
  # Inputs
+ PROTOC_EXEC
  PROTO_PATH
  DEPENDENCY_DESCRIPTIONS
  OUTPUT_DIRECTORY
@@ -148,6 +166,10 @@ function(gz_msgs_generate_desc_impl)
 
  cmake_parse_arguments(generate_messages "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
 
+ if (NOT DEFINED generate_messages_PROTOC_EXEC)
+ set(generate_messages_PROTOC_EXEC protobuf::protoc)
+ endif()
+
  set(ARGS)
  list(APPEND ARGS -I${generate_messages_PROTO_PATH})
  list(APPEND ARGS --descriptor_set_out=${generate_messages_OUTPUT_FILENAME})
@@ -161,7 +183,7 @@ function(gz_msgs_generate_desc_impl)
 
  add_custom_command(
  OUTPUT ${generate_messages_OUTPUT_FILENAME}
- COMMAND protobuf::protoc
+ COMMAND ${generate_messages_PROTOC_EXEC}
  ARGS ${ARGS}
  DEPENDS ${generate_messages_INPUT_PROTOS}
  COMMENT "Generating descriptor set"
@@ -175,6 +197,8 @@ endfunction()
 # TARGET - Target (static library) to create
 # PROTO_PACKAGE - Protobuf package the file belongs to (e.g. "gz.msgs")
 # MSGS_GEN_SCRIPT - Location of the messge generator script
+# PYTHON_INTERPRETER - Target or path to the python interpreter used
+# PROTOC_EXEC - Protoc target or executable to use
 # GZ_PROTOC_PLUGIN - Location of the gazebo generator plugin
 # FACTORY_GEN_SCRIPT - Location of the factory generator script
 # MSGS_LIB - gz-msgs library to link to
@@ -186,7 +210,7 @@ endfunction()
 # that depend on gz-msgs
 function(gz_msgs_generate_messages_lib)
  set(options "")
- set(oneValueArgs TARGET PROTO_PACKAGE MSGS_GEN_SCRIPT GZ_PROTOC_PLUGIN FACTORY_GEN_SCRIPT MSGS_LIB PROTO_PATH)
+ set(oneValueArgs TARGET PROTO_PACKAGE MSGS_GEN_SCRIPT PYTHON_INTERPRETER PROTOC_EXEC GZ_PROTOC_PLUGIN FACTORY_GEN_SCRIPT MSGS_LIB PROTO_PATH)
  set(multiValueArgs INPUT_PROTOS DEPENDENCIES)
 
  cmake_parse_arguments(generate_messages "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
@@ -205,9 +229,19 @@ function(gz_msgs_generate_messages_lib)
  list(APPEND depends_msgs_desc ${msgs_desc_file})
  endforeach()
 
+ # Default values for optional parameters
+ if (NOT DEFINED generate_messages_PYTHON_INTERPRETER)
+ set(generate_messages_PYTHON_INTERPRETER Python3::Interpreter)
+ endif()
+ if (NOT DEFINED generate_messages_PROTOC_EXEC)
+ set(generate_messages_PROTOC_EXEC protobuf::protoc)
+ endif()
+
  gz_msgs_generate_messages_impl(
  PROTO_PACKAGE ${generate_messages_PROTO_PACKAGE}
  MSGS_GEN_SCRIPT ${generate_messages_MSGS_GEN_SCRIPT}
+ PYTHON_INTERPRETER ${generate_messages_PYTHON_INTERPRETER}
+ PROTOC_EXEC ${generate_messages_PROTOC_EXEC}
  GZ_PROTOC_PLUGIN ${generate_messages_GZ_PROTOC_PLUGIN}
  FACTORY_GEN_SCRIPT ${generate_messages_FACTORY_GEN_SCRIPT}
  PROTO_PATH ${generate_messages_PROTO_PATH}
@@ -221,6 +255,7 @@ function(gz_msgs_generate_messages_lib)
  )
 
  gz_msgs_generate_desc_impl(
+ PROTOC_EXEC ${generate_messages_PROTOC_EXEC}
  INPUT_PROTOS ${generate_messages_INPUT_PROTOS}
  PROTO_PATH ${generate_messages_PROTO_PATH}
  DEPENDENCY_DESCRIPTIONS ${depends_msgs_desc}

cmake/gz_msgs_protoc.cmake

@@ -4,6 +4,7 @@
 # GENERATE_CPP - generates c++ code for the message if specified
 # GENERATE_PYTHON - generates python code for the message if specified
 # One value arguments:
+# PYTHON_INTERPRETER - Target or path to the Python interpreter to use to run generation scripts
 # MSGS_GEN_SCRIPT - Path to the message generation python script
 # PROTO_PACKAGE - Protobuf package the file belongs to (e.g. "gz.msgs")
 # PROTOC_EXEC - Path to protoc
@@ -22,6 +23,7 @@
 function(gz_msgs_protoc)
  set(options GENERATE_CPP GENERATE_PYTHON)
  set(oneValueArgs
+ PYTHON_INTERPRETER
  MSGS_GEN_SCRIPT
  PROTO_PACKAGE
  PROTOC_EXEC
@@ -38,6 +40,13 @@ function(gz_msgs_protoc)
 
  cmake_parse_arguments(gz_msgs_protoc "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
 
+ if (NOT DEFINED gz_msgs_protoc_PYTHON_INTERPRETER)
+ set(gz_msgs_protoc_PYTHON_INTERPRETER Python3::Interpreter)
+ endif()
+ if (NOT DEFINED gz_msgs_protoc_PROTOC_EXEC)
+ set(gz_msgs_protoc_PROTOC_EXEC protobuf::protoc)
+ endif()
+
  get_filename_component(ABS_FIL ${gz_msgs_protoc_INPUT_PROTO} ABSOLUTE)
  get_filename_component(FIL_WE ${gz_msgs_protoc_INPUT_PROTO} NAME_WE)
 
@@ -85,8 +94,14 @@ function(gz_msgs_protoc)
  set(${gz_msgs_protoc_OUTPUT_PYTHON_VAR} ${${gz_msgs_protoc_OUTPUT_PYTHON_VAR}} PARENT_SCOPE)
  endif()
 
+ if(TARGET ${gz_msgs_protoc_PROTOC_EXEC})
+ set(gz_msgs_protoc_PROTOC_EXEC_FILE_ABS_PATH "$<TARGET_FILE:${gz_msgs_protoc_PROTOC_EXEC}>")
+ else()
+ set(gz_msgs_protoc_PROTOC_EXEC_FILE_ABS_PATH ${gz_msgs_protoc_PROTOC_EXEC})
+ endif()
+
  set(GENERATE_ARGS
- --protoc-exec "$<TARGET_FILE:${gz_msgs_protoc_PROTOC_EXEC}>"
+ --protoc-exec "${gz_msgs_protoc_PROTOC_EXEC_FILE_ABS_PATH}"
  --gz-generator-bin "${gz_msgs_protoc_GZ_PROTOC_PLUGIN}"
  --proto-path "${gz_msgs_protoc_PROTO_PATH}"
  --input-path "${ABS_FIL}"
@@ -118,7 +133,7 @@ function(gz_msgs_protoc)
 
  add_custom_command(
  OUTPUT ${output_files}
- COMMAND Python3::Interpreter
+ COMMAND ${gz_msgs_protoc_PYTHON_INTERPRETER}
  ARGS ${gz_msgs_protoc_MSGS_GEN_SCRIPT} ${GENERATE_ARGS}
  DEPENDS
  ${ABS_FIL}

core/CMakeLists.txt

@@ -26,13 +26,23 @@ include(${PROJECT_SOURCE_DIR}/cmake/gz_msgs_generate.cmake)
 include(${PROJECT_SOURCE_DIR}/cmake/gz_msgs_protoc.cmake)
 include(${PROJECT_SOURCE_DIR}/cmake/gz_msgs_string_utils.cmake)
 
+if(TARGET ${${PROJECT_NAME}_PROTO_GENERATOR_PLUGIN})
+ set(${PROJECT_NAME}_PROTO_GENERATOR_PLUGIN_FILE $<TARGET_FILE:${${PROJECT_NAME}_PROTO_GENERATOR_PLUGIN}>)
+else()
+ set(${PROJECT_NAME}_PROTO_GENERATOR_PLUGIN_FILE ${${PROJECT_NAME}_PROTO_GENERATOR_PLUGIN})
+endif()
+
 gz_msgs_generate_messages_impl(
  MSGS_GEN_SCRIPT
  ${PROJECT_SOURCE_DIR}/tools/gz_msgs_generate.py
  FACTORY_GEN_SCRIPT
  ${PROJECT_SOURCE_DIR}/tools/gz_msgs_generate_factory.py
+ PYTHON_INTERPRETER
+ ${${PROJECT_NAME}_PYTHON_INTERPRETER}
+ PROTOC_EXEC
+ ${${PROJECT_NAME}_PROTOC_EXECUTABLE}
  GZ_PROTOC_PLUGIN
- $<TARGET_FILE:${PROJECT_NAME}_protoc_plugin>
+ ${${PROJECT_NAME}_PROTO_GENERATOR_PLUGIN_FILE}
  INPUT_PROTOS
  ${proto_files}
  DLLEXPORT_DECL
@@ -54,6 +64,7 @@ gz_msgs_generate_messages_impl(
 )
 
 gz_msgs_generate_desc_impl(
+ PROTOC_EXEC ${${PROJECT_NAME}_PROTOC_EXECUTABLE}
  INPUT_PROTOS ${proto_files}
  PROTO_PATH ${PROJECT_SOURCE_DIR}/proto
  DEPENDENCY_DESCRIPTIONS ${depends_msgs_desc}

gz-msgs-extras.cmake.in

@@ -28,7 +28,16 @@ set(PROTO_SCRIPT_NAME "@PROJECT_NAME@_generate.py")
 set(FACTORY_SCRIPT_NAME "@PROJECT_NAME@_generate_factory.py")
 
 set(@PROJECT_NAME@_PROTO_PATH ${@PROJECT_NAME@_INSTALL_PATH}/share/protos)
-set(@PROJECT_NAME@_PROTO_GENERATOR_PLUGIN ${@PROJECT_NAME@_INSTALL_PATH}/bin/${PROTOC_NAME})
+# Provide support to override generator executable used during cross-compilation
+if(NOT DEFINED @PROJECT_NAME@_PROTO_GENERATOR_PLUGIN)
+ set(@PROJECT_NAME@_PROTO_GENERATOR_PLUGIN ${@PROJECT_NAME@_INSTALL_PATH}/bin/${PROTOC_NAME})
+endif()
+if(NOT DEFINED @PROJECT_NAME@_PROTOC_EXECUTABLE)
+ set(@PROJECT_NAME@_PROTOC_EXECUTABLE protobuf::protoc)
+endif()
+if(NOT DEFINED @PROJECT_NAME@_PYTHON_INTERPRETER)
+ set(@PROJECT_NAME@_PYTHON_INTERPRETER Python3::Interpreter)
+endif() 
 set(@PROJECT_NAME@_PROTO_GENERATOR_SCRIPT ${@PROJECT_NAME@_INSTALL_PATH}/bin/${PROTO_SCRIPT_NAME})
 set(@PROJECT_NAME@_FACTORY_GENERATOR_SCRIPT ${@PROJECT_NAME@_INSTALL_PATH}/bin/${FACTORY_SCRIPT_NAME})
 
@@ -64,6 +73,10 @@ function(gz_msgs_generate_messages)
 
  cmake_parse_arguments(generate_messages "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
  gz_msgs_generate_messages_lib(
+ PYTHON_INTERPRETER
+ ${@PROJECT_NAME@_PYTHON_INTERPRETER}
+ PROTOC_EXEC
+ ${@PROJECT_NAME@_PROTOC_EXECUTABLE}
  MSGS_GEN_SCRIPT
  ${@PROJECT_NAME@_PROTO_GENERATOR_SCRIPT}
  FACTORY_GEN_SCRIPT