gen/src/mod.rs

// Functionality that is shared between the cxx_build::bridge entry point and
// the cxxbridge CLI command.

mod error;
mod file;
pub(super) mod include;
pub(super) mod out;
mod write;

#[cfg(test)]
mod tests;

use self::error::{format_err, Error, Result};
use self::file::File;
use crate::syntax::report::Errors;
use crate::syntax::{self, check, Types};
use std::fs;
use std::path::Path;

#[derive(Default)]
pub(super) struct Opt {
    /// Any additional headers to #include
    pub include: Vec<String>,
    /// Whether to set __attribute__((visibility("default")))
    /// or similar annotations on function implementations.
    pub cxx_impl_annotations: Option<String>,
}

pub(super) fn do_generate_bridge(path: &Path, opt: Opt) -> Vec<u8> {
    let header = false;
    generate_from_path(path, opt, header)
}

pub(super) fn do_generate_header(path: &Path, opt: Opt) -> Vec<u8> {
    let header = true;
    generate_from_path(path, opt, header)
}

fn generate_from_path(path: &Path, opt: Opt, header: bool) -> Vec<u8> {
    let source = match fs::read_to_string(path) {
        Ok(source) => source,
        Err(err) => format_err(path, "", Error::Io(err)),
    };
    let mut source = source.as_str();
    if source.starts_with("#!") && !source.starts_with("#![") {
        let shebang_end = source.find('\n').unwrap_or(source.len());
        source = &source[shebang_end..];
    }
    match generate(source, opt, header) {
        Ok(out) => out,
        Err(err) => format_err(path, source, err),
    }
}

fn generate(source: &str, opt: Opt, header: bool) -> Result<Vec<u8>> {
    proc_macro2::fallback::force();
    let ref mut errors = Errors::new();
    let syntax: File = syn::parse_str(source)?;
    let bridge = syntax
        .modules
        .into_iter()
        .next()
        .ok_or(Error::NoBridgeMod)?;
    let ref namespace = bridge.namespace;
    let ref apis = syntax::parse_items(errors, bridge.content);
    let ref types = Types::collect(errors, apis);
    errors.propagate()?;
    check::typecheck(errors, namespace, apis, types);
    errors.propagate()?;
    let out = write::gen(namespace, apis, types, opt, header);
    Ok(out.content())
}