[vlc-devel] [PATCH 1/2] libvlc: Add Rust API for writing modules in rust

[Alexandre Janniaux]

Hi,

On Sun, Sep 20, 2020 at 05:21:55PM +0530, Kartik Ohri wrote:
> On Sun, Sep 20, 2020 at 4:48 PM Alexandre Janniaux <ajanni at videolabs.io>
> wrote:
> > The point of using Meson integration is actually that it is
> > limited. ;)
> >
> > In my opinion, it would also greatly simplify the build
> > definitions by removing toml files, greatly decrease
> > compilation time if we are to integrate more Rust, and
> > provide a unified build system that all developers will
> > manipulate, be them Rust developers or not, so making the
> > Rust integration quite like the C++ one.
> >
> >
> Makes sense. I do not currently know how we could do without toml files.
> Rust ecosystem is heavily centered around cargo. More research is required
> into working of meson and cargo to understand how we should approach this.
> At the least it seems we would have to give up using external crates which
> may or may not be a hindrance. The cargo.toml files are pretty minimal and
> will be almost similar for all modules. However, that may be only me.

Actually no, you can have a converter for Rust toml project
into meson subprojects in a few lines of code, it gets a bit
more difficult with build.rs-based builds but we could just
try to prevent them as much as possible.

We can probably defer this to until we get meson in-tree
though, but it might need preliminary care about what we
integrate.

In particular, it means that crates will need to go into the
contrib system, and some crates are likely to need the world
to be compiled, or very specific version of some libraries
without rational. Such crate should be avoided or modified
upstream in my opinion. And finally we might need scripts to
update the contrib system crates version according to what
crates.io tells us is compatible with (I don't think we want
to ship multiple times the same crate just like we will with
the current cargo/contrib integration).

It might also be interesting to check debian's packaging for
crates, which could bring a symmetrical situation with all
the non-rust dependencies in the current tree through usual
tools like pkg-config.

> Rust ecosystem is heavily centered around cargo.

While I agree with this, and it's certainly much easier
to start with this, Rust is just yet another programming
language and though the first experience and crate/cargo
experience is really good, my point is that it's not
necessarily suitable in every situation and in particular
in cross-language with multiple targets projects. Meson
is likely to be the best tradeoff regarding those complex
constraints.

Regards,
--
Alexandre Janniaux
Videolabs