1/*
2 * Copyright (c) 2022 Huawei Device Co., Ltd.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 *     http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16//! rustc demangle for Rust.
17
18#![feature(rustc_private)]
19extern crate rustc_demangle;
20
21use std::alloc::{GlobalAlloc, Layout, System};
22use std::io::Write;
23use std::os::raw::{c_char};
24use std::ptr;
25use std::result::Result::{Ok, Err};
26
27/// # Safety
28///
29/// C-style interface for demangling.
30#[no_mangle]
31pub unsafe extern "C" fn rustc_demangle(mangled: *const c_char) -> *mut c_char
32{
33    if mangled.is_null() {
34        return ptr::null_mut();
35    }
36    let mangled_str = match std::ffi::CStr::from_ptr(mangled).to_str() {
37        Ok(s) => s,
38        Err(_) => return ptr::null_mut(),
39    };
40
41    match rustc_demangle::try_demangle(mangled_str) {
42        Ok(demangle) => {
43            let size = demangle.to_string().len();
44            let out = unsafe { System.alloc_zeroed(Layout::from_size_align_unchecked(size, 1)) };
45            if out.is_null() {
46                return ptr::null_mut();
47            }
48
49            match write!(unsafe { std::slice::from_raw_parts_mut(out, size) }, "{:#}\0", demangle) {
50                Ok(_) => {
51                    unsafe { std::slice::from_raw_parts_mut(out, size) }.as_mut_ptr() as *mut c_char
52                }
53                Err(_) => ptr::null_mut(),
54            }
55        }
56        Err(_) => ptr::null_mut(),
57    }
58}
59