blob: 2e6f84adaf7dc24bd3c1fec82eb20bec3116c41f [file] [log] [blame]
// Protocol Buffers - Google's data interchange format
// Copyright 2024 Google LLC. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
use crate::{upb_MiniTable, RawMessage};
extern "C" {
/// Returns the minimum needed length (excluding NULL) that `buf` has to be
/// to hold the `msg`s debug string.
///
/// SAFETY:
/// - `msg` is pointing at a valid upb_Message with associated minitable
/// `mt`
/// - `buf` is legally writable for `size` bytes (`buf` may be nullptr if
/// `size` is 0)
fn upb_DebugString(
msg: RawMessage,
mt: *const upb_MiniTable,
options: i32,
buf: *mut u8,
size: usize,
) -> usize;
}
#[allow(dead_code)]
#[repr(i32)]
enum Options {
// When set, prints everything on a single line.
SingleLine = 1,
// When set, unknown fields are not printed.
SkipUnknown = 2,
// When set, maps are *not* sorted (this avoids allocating tmp mem).
NoSortMaps = 4,
}
/// Returns a string of field number to value entries of a message.
///
/// # Safety
/// - `mt` must correspond to the `msg`s minitable.
pub unsafe fn debug_string(msg: RawMessage, mt: *const upb_MiniTable) -> String {
// Only find out the length first to then allocate a buffer of the minimum size
// needed.
// SAFETY:
// - `msg` is a legally dereferencable upb_Message whose associated minitable is
// `mt`
// - `buf` is nullptr and `buf_len` is 0
let len =
unsafe { upb_DebugString(msg, mt, Options::NoSortMaps as i32, std::ptr::null_mut(), 0) };
assert!(len < isize::MAX as usize);
// +1 for the trailing NULL
let mut buf = vec![0u8; len + 1];
// SAFETY:
// - `msg` is a legally dereferencable upb_Message whose associated minitable is
// `mt`
// - `buf` is legally writable for 'buf_len' bytes
let written_len = unsafe {
upb_DebugString(msg, mt, Options::NoSortMaps as i32, buf.as_mut_ptr(), buf.len())
};
assert_eq!(len, written_len);
String::from_utf8_lossy(buf.as_slice()).to_string()
}