Function as_opt_str

libs/darwin-kperf/src/database.rs:65–77

Reads a possibly-null `*const c_char` as an `Option<&str>`. # Safety If `field` is non-null, it must point to a valid NUL-terminated C string whose bytes are valid UTF-8, and the backing memory must remain alive and unmodified for at least `'db`.

(field: *const c_char)

/// whose bytes are valid UTF-8, and the backing memory must remain alive and
/// unmodified for at least `'db`.
const unsafe fn as_opt_str<'db>(field: *const c_char) -> Option<&'db str> {
    if field.is_null() {
        return None;
    }

    // SAFETY: we just checked for null; caller guarantees validity otherwise.
    let str = unsafe { CStr::from_ptr(field).to_str() };

    match str {
        Ok(str) => Some(str),
        Err(_) => panic!("string is not utf-8"),
    }
}

/// CPU architecture reported by the PMC database.
///