Generating the FFI library

First, you'll need to download gir:

> git clone https://github.com/gtk-rs/gir
> cd gir
> cargo install --path . # so we can use gir binary directly

Then the .gir files (luckily for you, we have a repository which contains all the ones you need for sourceview!):

> git clone https://github.com/gtk-rs/gir-files

If you look into gir-files, you'll see a file named GtkSource-3.0.gir. That's the one for sourceview.

Now let's create a new project for our sourceview crate:

> cargo new sourceview --lib

Then let's create a folder inside the newly created sourceview folder for the sys part:

> cd sourceview
> cargo new sourceview-sys --lib

To indicate to gir what to generate, we'll need a Gir.toml file (inside the sourceview-sys folder) containing:

[options]
library = "GtkSource"
version = "3.0"
target_path = "."
min_cfg_version = "3.0"

• library stands for the library we want to generate.
• version stands for the version of the library to be used.
• target_path stands for the location where the files will be generated.
• min_cfg_version will be the minimum version supported by the generated bindings.

You should now have a folder looking like this:

sourceview/
  |
  |---- Cargo.toml
  |---- sourceview-sys/
  |       |
  |       |---- Cargo.toml
  |       |---- Gir.toml
  |       |---- src/
  |               |
  |               |---- lib.rs
  |---- src/
          |
          |---- lib.rs

Let's generate the sys crate now:

> cd sourceview-sys
> # Run gir in "sys" mode (the "-m" option) and we give the gir files path (the "-d" option)
> gir -m sys -d ../../gir-files/

(In case a failure happens at this point, and you can't figure out what's going on, don't hesitate to reach us so we can give you a hand!)

You should now see new files (and a new folder):

• build.rs
• Cargo.toml
• src/lib.rs
• tests/

Now let's try to build it:

> cargo build

Surprise! It doesn't build at all and you should see a loooooot of errors. Well, that was expected. We need to add some dependencies (you can find which ones in the .gir files) in order to make it work. Let's update our Gir.toml file to make it look like this:

[options]
library = "GtkSource"
version = "3.0"
target_path = "."
min_cfg_version = "3.0"

external_libraries = [
    "Cairo",
    "Gdk",
    "GdkPixbuf",
    "Gio",
    "GLib",
    "GObject",
    "Gtk",
]

Now we regenerate it then rebuild it:

> rm Cargo.* # we remove Cargo files
> gir -m sys -d ../../gir-files/
> cargo build

Should work just fine!

We can cleanup the command line a bit now. You can actually give the work mode ("-m" option) and the gir files repository through the Gir.toml file using "work_mode" and "girs_directories" options:

[options]
library = "GtkSource"
version = "3.0"
target_path = "."
min_cfg_version = "3.0"
work_mode = "sys"
girs_directories = ["../../gir-files/"]

external_libraries = [
    "Cairo",
    "Gdk",
    "GdkPixbuf",
    "Gio",
    "GLib",
    "GObject",
    "Gtk",
]

Now, if you want to regenerate, just run:

> gir

Now we have a working sys containing all functions and objects definition. Just to be sure everything was correctly generated, we can run some tests (graciously generated by gir as well):

> cargo test

Normally, all tests passed. If you get an error when running those tests, it's very likely that the sys generation is invalid and/or incomplete.

Time to generate the high-level Rust API!