Make resetting RealtimeBuffer easier by introducing a reset() method

[bmagyar]

Background

It turns out, some of our controllers forgot to reset their buffers when deactivating/reactivating!

We've implemented a quick fix for it in https://github.com/ros-controls/ros2_controllers/pull/246 (see the Files Changed tab) but it could be improved.

Resetting the buffer currently looks something like this:

  rt_command_ptr_ = realtime_tools::RealtimeBuffer<std::shared_ptr<CmdType>>(nullptr);

Oh no, that's long and ugly! :scream:

We'd rather like to see

  rt_command_ptr_->reset();

We need to change the RealtimeBuffer API for this and extend it with a reset() function that does the above. Go to https://github.com/ros-controls/realtime_tools/tree/foxy-devel (note the choice of the branch) and add said reset() function to the code. Open a Pull Request against the foxy-devel branch and once merged, replace that long and ugly line in this repository to make use of this new function!

Instructions

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[radekrudak]

Can reset function take pointer to o ject it belong to as argument ?

[bailaC]

@bmagyar , @destogl you can assign this to me. I will work on this.

[bmagyar]

This can proceed now further, the PR on realtime_tools was merged and released and synched to Foxy, Galactic and Rolling