[libcamera-devel] [PATCH] cam: convert to libfmt

[Tomi Valkeinen]

On 10/05/2022 10:16, Tomi Valkeinen wrote:
> This is just a conversation starter, not for merging. I really like
> libfmt, and I really hate the C++ stream-based string formatting. libfmt
> is the first library I add to any new C++ project I make.
> 
> You can find more information about libfmt from:
> 
> https://github.com/fmtlib/fmt
> https://fmt.dev/latest/index.html
> 
> This patch is just a crude conversion with ugly macros to showcase what
> the formatting code might look like.

As for the PR and EPR macros, those was just something to get forward 
with. I think fmt::print("") is fine, but fmt::print(stderr, "") is a 
bit long.

Compared to cout, "fmt::print(" is actually shorter than "std::cout << 
", and without all those << and std::endl the lines are shorter.

Not so with cerr and fmt::print(stderr, (although in many cases the 
total length would still be shorter) but I think it makes sense to have 
a macro/inline func for error prints, if only to make it more obvious 
that it's an error print.

And, of course, libfmt could also be used for logging:

LOG(Camera, Error) << "Camera in " << camera_state_names[currentState]
		   << " state trying " << from << "() requiring state "
		   << camera_state_names[state];

to

LOG(Camera, Error, "Camera in {} state trying {}() requiring state {}",
     camera_state_names[currentState], from, camera_state_names[state]);

  Tomi