helpers.rs

// Citadel C bindings library (libcitadel)
// Written in 2020 by
//     Dr. Maxim Orlovsky <orlovsky@pandoracore.com>
//
// To the extent possible under law, the author(s) have dedicated all
// copyright and related and neighboring rights to this software to
// the public domain worldwide. This software is distributed without
// any warranty.

// TODO: Consider moving to rust-amplify library

use libc::c_char;
use std::ffi::{CStr, CString};

pub trait TryIntoRaw {
    fn try_into_raw(self) -> Option<*const c_char>;
}

pub trait TryFromRaw {
    fn try_from_raw(ptr: *mut c_char) -> Option<Self>
    where
        Self: Sized;
}

impl TryIntoRaw for String {
    fn try_into_raw(self) -> Option<*const c_char> {
        CString::new(self)
            .map(CString::into_raw)
            .map(|ptr| ptr as *const c_char)
            .ok()
    }
}

impl TryFromRaw for String {
    fn try_from_raw(ptr: *mut c_char) -> Option<String> {
        unsafe { CString::from_raw(ptr) }.into_string().ok()
    }
}

pub trait TryAsStr {
    fn try_as_str(self) -> Option<&'static str>;
}

pub trait TryIntoString {
    fn try_into_string(self) -> Option<String>;
}

impl TryAsStr for *const c_char {
    fn try_as_str(self: *const c_char) -> Option<&'static str> {
        if self.is_null() {
            return None;
        }
        unsafe { CStr::from_ptr(self) }.to_str().ok()
    }
}

impl TryIntoString for *mut c_char {
    fn try_into_string(self: *mut c_char) -> Option<String> {
        if self.is_null() {
            return None;
        }
        String::try_from_raw(self)
    }
}

/*
impl Try for *const c_char {
    type Ok = *const c_char;
    type Error = ();

    fn into_result(self) -> Result<Self::Ok, Self::Error> {
        if self.is_null() {
            Err(())
        } else {
            Ok(self)
        }
    }

    fn from_error(v: Self::Error) -> Self {
        std::ptr::null()
    }

    fn from_ok(v: Self::Ok) -> Self {
        v
    }
}
*/