symlinkccc

A tool to SYMbolically LINK Catkin Compile Commands.

Getting started

Install rust, and make sure it is in your PATH by adding

test -f "${HOME}/.cargo/env" && source "${HOME}/.cargo/env" 

to your .bashrc file (or equivalent).

Install this package using:

cargo install symlinkccc

Then, in a catkin workspace:

catkin config --cmake-args -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
catkin build 
symlinkccc

This command is pretty quick, especially compared to the average catkin build time, so I made a wrapper for catkin, which executes the symlinkccc program after each catkin build, while passing through any arguments. Add this to your .bashrc file (or equivalent).

_catkin_wrapper () {
    if (( $# == 0 ))
    then
        \catkin 
    else
        if [[ $1 == "build" ]]
        then 
            \catkin build ${@:2} && symlinkccc
        else 
            \catkin $@
        fi
    fi
}

alias catkin="_catkin_wrapper"

Why?

ROS is an extremely useful framework when working anywhere near the robotics field, and catkin is an extremely useful set of tools for building and generally handling all the ROS packages. clangd is a very nice language server for the C++ programming language. However, catkin and clangd are not really friends...

clangd requires a compile_commands.json-file in order to understand which dependencies a package has. This can be generated by the cmake build tool, which catkin calls under the hood. To make catkin generate these files, add -DCMAKE_EXPORT_COMPILE_COMMANDS=ON to the cmake arguments, e.g. like this:

catkin config --cmake-args -DCMAKE_EXPORT_COMPILE_COMMANDS=ON

The problem is that catkin places the compile_commands.json-files in the build folder for each individual package, while clangd wants it in the root of the source folder for each package (as it is slightly more likely that you'll edit code from the source folder compared to the build folder). An advantage of ROS/catkin is that

TODOs

Some things I'd like to explore if I have time. I doubt too much of this will have an impact on the actual performance.

• Fix warning due to workspace being the name of a mod and multiple other things
• Use async
• Async handling of source and build directories
• Async loading files (package.xml/CMakeLists.txt)
• Async linking of different files
• Test if cargo watch can be used to check if something has to be re-linked
• Try to get the rospack command implemented purely in rust
• See if links can be juggled for profiles rather than just removing the old link for every time the program is executed
• Look to minimize the size of the binary by eliminating unneccessary dependencies.
• Can ROS compile on pure Windows? If so the symlink won't work.