bindings/cpp/build.rs

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// distributed with this work for additional information
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// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
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// specific language governing permissions and limitations
// under the License.

#[cfg(feature = "async")]
mod build_async {
    use std::{
        env::var,
        io,
        path::{Path, PathBuf},
    };

    fn copy_force<P: AsRef<Path>, Q: AsRef<Path>>(src: P, dst: Q) -> io::Result<()> {
        if dst.as_ref().exists() {
            std::fs::remove_file(&dst)?;
        }

        std::fs::copy(src, dst)?;
        Ok(())
    }

    pub fn symlink_async_includes() {
        let async_inc = var("DEP_CXX_ASYNC_INCLUDE").unwrap();
        let src_dir = PathBuf::from(async_inc).join("rust");

        let prj_dir = var("CARGO_MANIFEST_DIR").unwrap();
        let dst_dir = PathBuf::from(prj_dir)
            .join("target")
            .join("cxxbridge")
            .join("rust");

        copy_force(src_dir.join("cxx_async.h"), dst_dir.join("cxx_async.h")).unwrap();
    }
}

fn main() {
    let _ = cxx_build::bridge("src/lib.rs");
    #[cfg(feature = "async")]
    {
        let _ = cxx_build::bridge("src/async.rs");
        build_async::symlink_async_includes();
    }

    println!("cargo:rerun-if-changed=src/lib.rs");
    #[cfg(feature = "async")]
    println!("cargo:rerun-if-changed=src/async.rs");
}