cxx 0.3.0

Safe interop between Rust and C++
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75

use std::mem::{self, ManuallyDrop, MaybeUninit};
use std::ptr;
use std::slice;
use std::str;

#[repr(C)]
pub struct RustString {
    repr: String,
}

impl RustString {
    pub fn from(s: String) -> Self {
        RustString { repr: s }
    }

    pub fn from_ref(s: &String) -> &Self {
        unsafe { &*(s as *const String as *const RustString) }
    }

    pub fn into_string(self) -> String {
        self.repr
    }

    pub fn as_string(&self) -> &String {
        &self.repr
    }

    pub fn as_mut_string(&mut self) -> &mut String {
        &mut self.repr
    }
}

#[export_name = "cxxbridge03$string$new"]
unsafe extern "C" fn string_new(this: &mut MaybeUninit<String>) {
    ptr::write(this.as_mut_ptr(), String::new());
}

#[export_name = "cxxbridge03$string$clone"]
unsafe extern "C" fn string_clone(this: &mut MaybeUninit<String>, other: &String) {
    ptr::write(this.as_mut_ptr(), other.clone());
}

#[export_name = "cxxbridge03$string$from"]
unsafe extern "C" fn string_from(
    this: &mut MaybeUninit<String>,
    ptr: *const u8,
    len: usize,
) -> bool {
    let slice = slice::from_raw_parts(ptr, len);
    match str::from_utf8(slice) {
        Ok(s) => {
            ptr::write(this.as_mut_ptr(), s.to_owned());
            true
        }
        Err(_) => false,
    }
}

#[export_name = "cxxbridge03$string$drop"]
unsafe extern "C" fn string_drop(this: &mut ManuallyDrop<String>) {
    ManuallyDrop::drop(this);
}

#[export_name = "cxxbridge03$string$ptr"]
unsafe extern "C" fn string_ptr(this: &String) -> *const u8 {
    this.as_ptr()
}

#[export_name = "cxxbridge03$string$len"]
unsafe extern "C" fn string_len(this: &String) -> usize {
    this.len()
}

const_assert_eq!(mem::size_of::<[usize; 3]>(), mem::size_of::<String>());
const_assert_eq!(mem::align_of::<usize>(), mem::align_of::<String>());