cxx 0.5.1

Safe interop between Rust and C++
Documentation 
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use cxx_test_suite::ffi;
use std::cell::Cell;
use std::ffi::CStr;

thread_local! {
    static CORRECT: Cell<bool> = Cell::new(false);
}

#[no_mangle]
extern "C" fn cxx_test_suite_set_correct() {
    CORRECT.with(|correct| correct.set(true));
}

macro_rules! check {
    ($run:expr) => {{
        CORRECT.with(|correct| correct.set(false));
        $run;
        assert!(CORRECT.with(|correct| correct.get()), stringify!($run));
    }};
}

#[test]
fn test_c_return() {
    let shared = ffi::Shared { z: 2020 };

    assert_eq!(2020, ffi::c_return_primitive());
    assert_eq!(2020, ffi::c_return_shared().z);
    assert_eq!(2020, *ffi::c_return_box());
    ffi::c_return_unique_ptr();
    assert_eq!(2020, *ffi::c_return_ref(&shared));
    assert_eq!("2020", ffi::c_return_str(&shared));
    assert_eq!(b"2020\0", ffi::c_return_sliceu8(&shared));
    assert_eq!("2020", ffi::c_return_rust_string());
    assert_eq!("2020", ffi::c_return_unique_ptr_string().to_str().unwrap());
    assert_eq!(4, ffi::c_return_unique_ptr_vector_u8().len());
    assert_eq!(
        200_u8,
        ffi::c_return_unique_ptr_vector_u8().into_iter().sum(),
    );
    assert_eq!(
        200.5_f64,
        ffi::c_return_unique_ptr_vector_f64().into_iter().sum(),
    );
    assert_eq!(2, ffi::c_return_unique_ptr_vector_shared().len());
    assert_eq!(
        2021_usize,
        ffi::c_return_unique_ptr_vector_shared()
            .into_iter()
            .map(|o| o.z)
            .sum(),
    );
    assert_eq!(2020, ffi::c_return_identity(2020));
    assert_eq!(2021, ffi::c_return_sum(2020, 1));
    match ffi::c_return_enum(0) {
        enm @ ffi::Enum::AVal => assert_eq!(0, enm.repr),
        _ => assert!(false),
    }
    match ffi::c_return_enum(1) {
        enm @ ffi::Enum::BVal => assert_eq!(2020, enm.repr),
        _ => assert!(false),
    }
    match ffi::c_return_enum(2021) {
        enm @ ffi::Enum::CVal => assert_eq!(2021, enm.repr),
        _ => assert!(false),
    }
}

#[test]
fn test_c_try_return() {
    assert_eq!((), ffi::c_try_return_void().unwrap());
    assert_eq!(2020, ffi::c_try_return_primitive().unwrap());
    assert_eq!(
        "logic error",
        ffi::c_fail_return_primitive().unwrap_err().what(),
    );
    assert_eq!(2020, *ffi::c_try_return_box().unwrap());
    assert_eq!("2020", *ffi::c_try_return_ref(&"2020".to_owned()).unwrap());
    assert_eq!("2020", ffi::c_try_return_str("2020").unwrap());
    assert_eq!(b"2020", ffi::c_try_return_sliceu8(b"2020").unwrap());
    assert_eq!("2020", ffi::c_try_return_rust_string().unwrap());
    assert_eq!("2020", &*ffi::c_try_return_unique_ptr_string().unwrap());
}

#[test]
fn test_c_take() {
    let unique_ptr = ffi::c_return_unique_ptr();

    check!(ffi::c_take_primitive(2020));
    check!(ffi::c_take_shared(ffi::Shared { z: 2020 }));
    check!(ffi::c_take_box(Box::new(2020)));
    check!(ffi::c_take_ref_c(&unique_ptr));
    check!(cxx_test_suite::module::ffi::c_take_unique_ptr(unique_ptr));
    check!(ffi::c_take_str("2020"));
    check!(ffi::c_take_sliceu8(b"2020"));
    check!(ffi::c_take_rust_string("2020".to_owned()));
    check!(ffi::c_take_unique_ptr_string(
        ffi::c_return_unique_ptr_string()
    ));
    check!(ffi::c_take_unique_ptr_vector_u8(
        ffi::c_return_unique_ptr_vector_u8()
    ));
    check!(ffi::c_take_unique_ptr_vector_f64(
        ffi::c_return_unique_ptr_vector_f64()
    ));
    check!(ffi::c_take_unique_ptr_vector_shared(
        ffi::c_return_unique_ptr_vector_shared()
    ));
    check!(ffi::c_take_ref_vector(&ffi::c_return_unique_ptr_vector_u8()));
    let test_vec = [86_u8, 75_u8, 30_u8, 9_u8].to_vec();
    check!(ffi::c_take_rust_vec(test_vec.clone()));
    check!(ffi::c_take_rust_vec_index(test_vec.clone()));
    let shared_test_vec = vec![ffi::Shared { z: 1010 }, ffi::Shared { z: 1011 }];
    check!(ffi::c_take_rust_vec_shared(shared_test_vec.clone()));
    check!(ffi::c_take_rust_vec_shared_index(shared_test_vec.clone()));
    check!(ffi::c_take_rust_vec_shared_forward_iterator(
        shared_test_vec,
    ));
    check!(ffi::c_take_ref_rust_vec(&test_vec));
    check!(ffi::c_take_ref_rust_vec_index(&test_vec));
    check!(ffi::c_take_ref_rust_vec_copy(&test_vec));
    check!(ffi::c_take_enum(ffi::Enum::AVal));
}

/*
// https://github.com/dtolnay/cxx/issues/232
#[test]
fn test_c_callback() {
    fn callback(s: String) -> usize {
        if s == "2020" {
            cxx_test_suite_set_correct();
        }
        0
    }

    check!(ffi::c_take_callback(callback));
}
*/

#[test]
fn test_c_call_r() {
    fn cxx_run_test() {
        extern "C" {
            fn cxx_run_test() -> *const i8;
        }
        let failure = unsafe { cxx_run_test() };
        if !failure.is_null() {
            let msg = unsafe { CStr::from_ptr(failure as *mut std::os::raw::c_char) };
            eprintln!("{}", msg.to_string_lossy());
        }
    }
    check!(cxx_run_test());
}

#[test]
fn test_c_method_calls() {
    let mut unique_ptr = ffi::c_return_unique_ptr();

    let old_value = unique_ptr.get();
    assert_eq!(2020, old_value);
    assert_eq!(2021, unique_ptr.set(2021));
    assert_eq!(2021, unique_ptr.get());
    assert_eq!(old_value, unique_ptr.set2(old_value));
    assert_eq!(old_value, unique_ptr.get2());
    assert_eq!(2022, unique_ptr.set_succeed(2022).unwrap());
    assert!(unique_ptr.get_fail().is_err());
}

#[test]
fn test_enum_representations() {
    assert_eq!(0, ffi::Enum::AVal.repr);
    assert_eq!(2020, ffi::Enum::BVal.repr);
    assert_eq!(2021, ffi::Enum::CVal.repr);
}

#[no_mangle]
extern "C" fn cxx_test_suite_get_box() -> *mut cxx_test_suite::R {
    Box::into_raw(Box::new(2020usize))
}

#[no_mangle]
unsafe extern "C" fn cxx_test_suite_r_is_correct(r: *const cxx_test_suite::R) -> bool {
    *r == 2020
}

#[test]
fn test_rust_name_attribute() {
    assert_eq!("2020", ffi::i32_overloaded_function(2020));
    assert_eq!("2020", ffi::str_overloaded_function("2020"));
    let unique_ptr = ffi::c_return_unique_ptr();
    assert_eq!("2020", unique_ptr.i32_overloaded_method(2020));
    assert_eq!("2020", unique_ptr.str_overloaded_method("2020"));
}