A rust version of the KdPrint macro

[mhandb]

In C, the KdPrint macro is convenient to add trace only in checked builds.

In Rust, we could have something like this:

#[cfg(debug_assertions)]
#[macro_export]
macro_rules! kd_print {
    ($msg: expr) => {
        #[allow(unused_unsafe)]
        unsafe {
            DbgPrint(concat!($msg, "\0").as_ptr() as *mut i8)
        }
    };

    ($format: expr, $($arg:tt)*) => {
        #[allow(unused_unsafe)]
        unsafe {
             DbgPrint(concat!($format, "\0").as_ptr() as *mut i8, $($arg)*)
        }
    };
}

#[cfg(not(debug_assertions))]
#[macro_export]
macro_rules! kd_print {
    ($msg: expr) => {};
    ($format: expr, $($arg:tt)*) => {};
}

Which could be used this way

kd_print!("Log some value: %wZ\n", &some_unicode_string);

Here I kept the DbgPrint string formatting instead of relying on the Rust one.
The purpose is to be able to easily log a UNICODE_STRING.
But having a UNICODE_STRING type which is displayable with println! would be better.

Having something similar which is built-in the crate, would be nice, at least for me :-) .

[wmmc88]

The wdk crate with the alloc feature enabled does actually provide implementations for println and print that use alloc features to print via DbgPrint. Albeit, using alloc features in their given state have some unresolved safety considerations per discussions in #5 and #6.

But having a UNICODE_STRING type which is displayable with println! would be better.

I agree. When we get to wrappers for UNICODE_STRING, something we could do is implement fmt::Display for the type.