comhelpers.rs

use com::{
    runtime::{init_apartment, ApartmentType},
    sys::CoCreateInstance,
    ComInterface, ComPtr, ComRc, CLSID, IID,
};

fn errorhandler<T, F>(f: F, error: HRESULT, retry: u32) -> Result<T, HRESULT>
where
    F: Fn() -> Result<T, HRESULT>,
{
    if retry == 0 {
        Err(error)
    } else {
        match error {
            // Com class is not registered
            HRESULT(0x80040154) => comrun(f, retry),

            // Com not initialized
            HRESULT(0x800401F0) => {
                init_apartment(ApartmentType::Multithreaded).map_err(HRESULT::from_i32)?;
                comrun(f, retry)
            }

            // RPC went away
            HRESULT(0x800706BA) => comrun(f, retry),

            // Others as is
            HRESULT(v) => Err(HRESULT(v)),
        }
    }
}

fn comrun<T, F>(f: F, retry: u32) -> Result<T, HRESULT>
where
    F: Fn() -> Result<T, HRESULT>,
{
    match f() {
        Ok(v) => Ok(v),
        Err(err) => errorhandler(f, err, retry - 1),
    }
}

pub fn run<F, T>(f: F) -> Result<T, HRESULT>
where
    F: Fn() -> Result<T, HRESULT>,
{
    comrun(f, 6)
}