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Convert package to a pure CMake package #285

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40 changes: 15 additions & 25 deletions CMakeLists.txt
Original file line number Diff line number Diff line change
@@ -1,31 +1,11 @@
cmake_minimum_required(VERSION 2.8.3)
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project(serial)

# Find catkin
find_package(catkin REQUIRED)

if(APPLE)
find_library(IOKIT_LIBRARY IOKit)
find_library(FOUNDATION_LIBRARY Foundation)
endif()

if(UNIX AND NOT APPLE)
# If Linux, add rt and pthread
set(rt_LIBRARIES rt)
set(pthread_LIBRARIES pthread)
catkin_package(
LIBRARIES ${PROJECT_NAME}
INCLUDE_DIRS include
DEPENDS rt pthread
)
else()
# Otherwise normal call
catkin_package(
LIBRARIES ${PROJECT_NAME}
INCLUDE_DIRS include
)
endif()

## Sources
set(serial_SRCS
src/serial.cc
Expand Down Expand Up @@ -66,16 +46,26 @@ include_directories(include)

## Install executable
install(TARGETS ${PROJECT_NAME}
ARCHIVE DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
LIBRARY DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
RUNTIME DESTINATION ${CATKIN_GLOBAL_BIN_DESTINATION}
ARCHIVE DESTINATION lib
LIBRARY DESTINATION lib
RUNTIME DESTINATION bin
)

## Install headers
install(FILES include/serial/serial.h include/serial/v8stdint.h
DESTINATION ${CATKIN_GLOBAL_INCLUDE_DESTINATION}/serial)
DESTINATION include/serial)

## Install CMake config
install(FILES cmake/serialConfig.cmake
DESTINATION share/serial/cmake)


## Install package.xml
install(FILES package.xml
DESTINATION share/serial)
Comment on lines +80 to +89
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This might be a good time to change to exported targets, and also consider putting the headers in a separate subfolder, which we've been doing in ROS 2 for a while now to promote better header isolation in a merged install space.

I.e. we'd put the headers in include/serial/serial and the exported include flags would be like -I/path/to/include/serial with the code still doing #include "serial/serial.h".


## Tests
if(CATKIN_ENABLE_TESTING)
include(CTest)
if(BUILD_TESTING)
add_subdirectory(tests)
endif()
4 changes: 2 additions & 2 deletions Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -56,7 +56,7 @@ test:
@mkdir -p build
cd build && cmake $(CMAKE_FLAGS) ..
ifneq ($(MAKE),)
cd build && $(MAKE) run_tests
cd build && $(MAKE) all test
else
cd build && make run_tests
cd build && make all test
endif
3 changes: 3 additions & 0 deletions cmake/serialConfig.cmake
Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
get_filename_component(SERIAL_CMAKE_DIR "${CMAKE_CURRENT_LIST_FILE}" PATH)
set(SERIAL_INCLUDE_DIRS "${SERIAL_CMAKE_DIR}/../../../include")
find_library(SERIAL_LIBRARIES serial PATHS ${SERIAL_CMAKE_DIR}/../../../lib/serial)
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@ChrisThrasher ChrisThrasher Jun 15, 2023

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If we're adding a config module, we should write a config module that exports a target instead of doing the old school approach of setting some variables that downstream projects have to use. That means we need to create an export set for the library target and install that export set then this file becomes a one liner that will look something like this:

include(${CMAKE_CURRENT_LIST_DIR}/serial-targets.cmake)

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@ChrisThrasher can you point to helpful documentation and examples on how to do this well?

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@ChrisThrasher ChrisThrasher Jun 15, 2023

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https://github.com/ChrisThrasher/argon/blob/9a2982c5471f06ca1d97f8d2d8a1aab3055ba456/CMakeLists.txt#L29-L42

I'm biased but this installation code I wrote I quite like. It's goes above and beyond to be as robust and idiomatic as possible. You don't need to copy everything it does but it should do a good job laying our the basic steps.

  1. Install all public headers. I do this by installing the entire include/ directory.
  2. Create export set. This happens to only include a single library target but may include more if need be. It uses variables from the GNUInstallDirs module to ensure all files are installed in platform-appropriate locations that can be easily modified by the user should they want to install the library in a different location. I include the package name and version in the install tree but you can omit that.
  3. Install said export set. This is where you can (and should) specify a namespace for all exported targets.
  4. Create a version config file. This ensures that users can ask for a specific version and that will be checked against the version that is installed.
  5. Install the config module and the version config file.

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instead of doing the old school approach of setting some variables that downstream projects have to use.

This is not old-school. The normal usage pattern would be something like below, assuming that the serial library lives in a subdirectory

include(libs/serial)
target_link_libraries(${PROJECT_NAME} PRIVATE wjserial::serial)

This would just require a one-liner in CMakeLists.txt defining a ALIAS target. It relies on cmake's support for transitive dependencies. Adding such a target would simplify documentation and overall usage a lot.

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@ChrisThrasher ChrisThrasher Jun 22, 2023

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Yes, that's what I'm saying. We're in agreement. The variable-based approach is old school because targets are the modern way of doing things.

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It aids in readability and grepability if you simply spell out the variable name.

This is actually a personal preference... I actually agree on the personal level, but let's face it: the use of ${PROJECT_NAME} is common enough in the cmake community to leave in place.

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Don't mistake commonality for it being a good idea. Lots of bad practices are still popular but that should not be used as an argument in favor of perpetuating bad ideas.

9 changes: 8 additions & 1 deletion package.xml
Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,13 @@
<author email="[email protected]">William Woodall</author>
<author email="[email protected]">John Harrison</author>

<buildtool_depend>catkin</buildtool_depend>
<buildtool_depend>cmake</buildtool_depend>

<!-- boost is only needed for test/proof_of_concepts which are not enabled by default -->
<!--test_depend>boost</test_depend-->
<test_depend>gtest</test_depend>

<export>
<build_type>cmake</build_type>
</export>
</package>
15 changes: 11 additions & 4 deletions tests/CMakeLists.txt
Original file line number Diff line number Diff line change
@@ -1,12 +1,19 @@
if(UNIX)
catkin_add_gtest(${PROJECT_NAME}-test unix_serial_tests.cc)
target_link_libraries(${PROJECT_NAME}-test ${PROJECT_NAME})
find_package(GTest REQUIRED)
include_directories(${GTEST_INCLUDE_DIRS})
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add_executable(${PROJECT_NAME}-test unix_serial_tests.cc)
target_link_libraries(${PROJECT_NAME}-test ${PROJECT_NAME} ${GTEST_LIBRARIES})
if(NOT APPLE)
target_link_libraries(${PROJECT_NAME}-test util)
endif()
add_test("${PROJECT_NAME}-test-gtest" ${PROJECT_NAME}-test)

if(NOT APPLE) # these tests are unreliable on macOS
catkin_add_gtest(${PROJECT_NAME}-test-timer unit/unix_timer_tests.cc)
target_link_libraries(${PROJECT_NAME}-test-timer ${PROJECT_NAME})
add_executable(${PROJECT_NAME}-test-timer unit/unix_timer_tests.cc)
target_link_libraries(${PROJECT_NAME}-test-timer ${PROJECT_NAME} ${GTEST_LIBRARIES})
add_test("${PROJECT_NAME}-test-timer-gtest" ${PROJECT_NAME}-test-timer)
endif()
# Boost is only required for tests/proof_of_concepts which are not enabled by default
# find_package(Boost REQUIRED)
endif()