Interface LanguageMethods

crates/test/src/lib.rs:1184–1288

Helper trait for each language to implement which encapsulates language-specific logic.

/// Helper trait for each language to implement which encapsulates
/// language-specific logic.
trait LanguageMethods {
    /// Display name for this language, used in filenames.
    fn display(&self) -> &str;

    /// Returns the prefix that this language uses to annotate configuration in
    /// the top of source files.
    ///
    /// This should be the language's line-comment syntax followed by `@`, e.g.
    /// `//@` for Rust or `;;@` for WebAssembly Text.
    fn comment_prefix_for_test_config(&self) -> Option<&str>;

    /// Returns the extra permutations, if any, of arguments to use with codegen
    /// tests.
    ///
    /// This is used to run all codegen tests with a variety of bindings
    /// generator options. The first element in the tuple is a descriptive
    /// string that should be unique (used in file names) and the second elemtn
    /// is the list of arguments for that variant to pass to the bindings
    /// generator.
    fn codegen_test_variants(&self) -> &[(&str, &[&str])] {
        &[]
    }

    /// Performs any one-time preparation necessary for this language, such as
    /// downloading or caching dependencies.
    fn prepare(&self, runner: &mut Runner) -> Result<()>;

    /// Add some files to the generated directory _before_ calling bindgen
    fn generate_bindings_prepare(
        &self,
        _runner: &Runner,
        _bindgen: &Bindgen,
        _dir: &Path,
    ) -> Result<()> {
        Ok(())
    }

    /// Generates bindings for `component` into `dir`.
    ///
    /// Runs `wit-bindgen` in aa subprocess to catch failures such as panics.
    fn generate_bindings(&self, runner: &Runner, bindgen: &Bindgen, dir: &Path) -> Result<()> {
        let name = match self.bindgen_name() {
            Some(name) => name,
            None => return Ok(()),
        };
        self.generate_bindings_prepare(runner, bindgen, dir)?;
        let mut cmd = Command::new(&runner.wit_bindgen);
        cmd.arg(name)
            .arg(&bindgen.wit_path)
            .arg("--world")
            .arg(format!("%{}", bindgen.world))
            .arg("--out-dir")
            .arg(dir);

        match bindgen.wit_config.default_bindgen_args {
            Some(true) | None => {
                for arg in self.default_bindgen_args() {
                    cmd.arg(arg);