unsafe_libyaml/

lib.rs

//! A line-by-line translation of libyaml from C to unsafe Rust.

#![no_std]
#![allow(non_camel_case_types, non_snake_case, unsafe_op_in_unsafe_fn, unused_assignments)]
#![warn(clippy::pedantic)]
#![allow(
    clippy::bool_to_int_with_if,
    clippy::cast_lossless,
    clippy::cast_possible_truncation,
    clippy::cast_possible_wrap,
    clippy::cast_ptr_alignment,
    clippy::cast_sign_loss,
    clippy::collapsible_if,
    clippy::doc_markdown,
    clippy::fn_params_excessive_bools,
    clippy::if_not_else,
    clippy::items_after_statements,
    clippy::let_underscore_untyped,
    clippy::manual_range_contains,
    clippy::manual_swap,
    clippy::missing_panics_doc,
    clippy::missing_safety_doc,
    clippy::module_name_repetitions,
    clippy::must_use_candidate,
    clippy::nonminimal_bool,
    clippy::ptr_as_ptr,
    clippy::redundant_else,
    clippy::similar_names,
    clippy::single_match,
    clippy::single_match_else,
    clippy::too_many_arguments,
    clippy::too_many_lines,
    clippy::uninlined_format_args,
    clippy::unnecessary_cast,
    clippy::unreadable_literal,
    clippy::while_immutable_condition, // https://github.com/rust-lang/rust-clippy/issues/3548
)]

extern crate alloc;

use core::mem::size_of;

mod libc {
    pub use core::{
        ffi::c_void,
        primitive::{i8 as c_char, i32 as c_int, i64 as c_long, u8 as c_uchar, u32 as c_uint, u64 as c_ulong},
    };
}

#[macro_use]
mod externs {
    use alloc::alloc::{self as rust, Layout};
    use core::{
        mem::{self, MaybeUninit},
        ptr, slice,
    };

    use crate::{
        libc,
        ops::{ForceAdd as _, ForceInto as _, die},
    };

    const HEADER: usize = {
        let need_len = mem::size_of::<usize>();
        // Round up to multiple of MALLOC_ALIGN.
        (need_len + MALLOC_ALIGN - 1) & !(MALLOC_ALIGN - 1)
    };

    // `max_align_t` may be bigger than this, but libyaml does not use `long
    // double` or u128.
    const MALLOC_ALIGN: usize = {
        let int_align = mem::align_of::<libc::c_ulong>();
        let ptr_align = mem::align_of::<usize>();
        if int_align >= ptr_align { int_align } else { ptr_align }
    };

    pub unsafe fn malloc(size: libc::c_ulong) -> *mut libc::c_void {
        let size = HEADER.force_add(size.force_into());
        let layout = Layout::from_size_align(size, MALLOC_ALIGN).ok().unwrap_or_else(die);
        let memory = rust::alloc(layout);
        if memory.is_null() {
            rust::handle_alloc_error(layout);
        }
        memory.cast::<usize>().write(size);
        memory.add(HEADER).cast()
    }

    pub unsafe fn realloc(ptr: *mut libc::c_void, new_size: libc::c_ulong) -> *mut libc::c_void {
        let mut memory = ptr.cast::<u8>().sub(HEADER);
        let size = memory.cast::<usize>().read();
        let layout = Layout::from_size_align_unchecked(size, MALLOC_ALIGN);
        let new_size = HEADER.force_add(new_size.force_into());
        let new_layout = Layout::from_size_align(new_size, MALLOC_ALIGN).ok().unwrap_or_else(die);
        memory = rust::realloc(memory, layout, new_size);
        if memory.is_null() {
            rust::handle_alloc_error(new_layout);
        }
        memory.cast::<usize>().write(new_size);
        memory.add(HEADER).cast()
    }

    pub unsafe fn free(ptr: *mut libc::c_void) {
        let memory = ptr.cast::<u8>().sub(HEADER);
        let size = memory.cast::<usize>().read();
        let layout = Layout::from_size_align_unchecked(size, MALLOC_ALIGN);
        rust::dealloc(memory, layout);
    }

    pub unsafe fn memcmp(lhs: *const libc::c_void, rhs: *const libc::c_void, count: libc::c_ulong) -> libc::c_int {
        let lhs = slice::from_raw_parts(lhs.cast::<u8>(), count as usize);
        let rhs = slice::from_raw_parts(rhs.cast::<u8>(), count as usize);
        lhs.cmp(rhs) as libc::c_int
    }

    pub unsafe fn memcpy(dest: *mut libc::c_void, src: *const libc::c_void, count: libc::c_ulong) -> *mut libc::c_void {
        ptr::copy_nonoverlapping(src.cast::<MaybeUninit<u8>>(), dest.cast::<MaybeUninit<u8>>(), count as usize);
        dest
    }

    pub unsafe fn memmove(
        dest: *mut libc::c_void,
        src: *const libc::c_void,
        count: libc::c_ulong,
    ) -> *mut libc::c_void {
        ptr::copy(src.cast::<MaybeUninit<u8>>(), dest.cast::<MaybeUninit<u8>>(), count as usize);
        dest
    }

    pub unsafe fn memset(dest: *mut libc::c_void, ch: libc::c_int, count: libc::c_ulong) -> *mut libc::c_void {
        ptr::write_bytes(dest.cast::<u8>(), ch as u8, count as usize);
        dest
    }

    pub unsafe fn strcmp(lhs: *const libc::c_char, rhs: *const libc::c_char) -> libc::c_int {
        let lhs = slice::from_raw_parts(lhs.cast::<u8>(), strlen(lhs) as usize);
        let rhs = slice::from_raw_parts(rhs.cast::<u8>(), strlen(rhs) as usize);
        lhs.cmp(rhs) as libc::c_int
    }

    pub unsafe fn strdup(src: *const libc::c_char) -> *mut libc::c_char {
        let len = strlen(src);
        let dest = malloc(len + 1);
        memcpy(dest, src.cast(), len + 1);
        dest.cast()
    }

    pub unsafe fn strlen(str: *const libc::c_char) -> libc::c_ulong {
        let mut end = str;
        while *end != 0 {
            end = end.add(1);
        }
        end.offset_from(str) as libc::c_ulong
    }

    pub unsafe fn strncmp(lhs: *const libc::c_char, rhs: *const libc::c_char, mut count: libc::c_ulong) -> libc::c_int {
        let mut lhs = lhs.cast::<u8>();
        let mut rhs = rhs.cast::<u8>();
        while count > 0 && *lhs != 0 && *lhs == *rhs {
            lhs = lhs.add(1);
            rhs = rhs.add(1);
            count -= 1;
        }
        if count == 0 {
            0
        } else {
            (*lhs).cmp(&*rhs) as libc::c_int
        }
    }

    macro_rules! __assert {
        (false $(,)?) => {
            $crate::externs::__assert_fail(stringify!(false), file!(), line!())
        };
        ($assertion:expr $(,)?) => {
            if !$assertion {
                $crate::externs::__assert_fail(stringify!($assertion), file!(), line!());
            }
        };
    }

    pub(crate) unsafe fn __assert_fail(__assertion: &'static str, __file: &'static str, __line: u32) -> ! {
        struct Abort;
        impl Drop for Abort {
            fn drop(&mut self) {
                panic!();
            }
        }
        let _abort_on_panic = Abort;
        panic!("{}:{}: Assertion `{}` failed.", __file, __line, __assertion);
    }
}

mod fmt {
    use core::{
        fmt::{self, Write},
        ptr,
    };

    use crate::yaml::yaml_char_t;

    pub struct WriteToPtr {
        ptr: *mut yaml_char_t,
    }

    impl WriteToPtr {
        pub unsafe fn new(ptr: *mut yaml_char_t) -> Self {
            WriteToPtr {
                ptr,
            }
        }

        pub fn write_fmt(&mut self, args: fmt::Arguments) {
            let _ = Write::write_fmt(self, args);
        }
    }

    impl Write for WriteToPtr {
        fn write_str(&mut self, s: &str) -> fmt::Result {
            unsafe {
                ptr::copy_nonoverlapping(s.as_ptr(), self.ptr, s.len());
                self.ptr = self.ptr.add(s.len());
            }
            Ok(())
        }
    }
}

trait PointerExt: Sized {
    fn c_offset_from(self, origin: Self) -> isize;
}

impl<T> PointerExt for *const T {
    fn c_offset_from(self, origin: *const T) -> isize {
        (self as isize - origin as isize) / size_of::<T>() as isize
    }
}

impl<T> PointerExt for *mut T {
    fn c_offset_from(self, origin: *mut T) -> isize {
        (self as isize - origin as isize) / size_of::<T>() as isize
    }
}

#[macro_use]
mod macros;

mod api;
mod dumper;
mod emitter;
mod loader;
mod ops;
mod parser;
mod reader;
mod scanner;
mod success;
mod writer;
mod yaml;

#[doc(hidden)]
pub use crate::yaml::{
    yaml_break_t::*, yaml_emitter_state_t::*, yaml_encoding_t::*, yaml_error_type_t::*, yaml_event_type_t::*,
    yaml_mapping_style_t::*, yaml_node_type_t::*, yaml_parser_state_t::*, yaml_scalar_style_t::*,
    yaml_sequence_style_t::*, yaml_token_type_t::*,
};
pub use crate::{
    api::{
        yaml_alias_event_initialize, yaml_document_add_mapping, yaml_document_add_scalar, yaml_document_add_sequence,
        yaml_document_append_mapping_pair, yaml_document_append_sequence_item, yaml_document_delete,
        yaml_document_end_event_initialize, yaml_document_get_node, yaml_document_get_root_node,
        yaml_document_initialize, yaml_document_start_event_initialize, yaml_emitter_delete, yaml_emitter_initialize,
        yaml_emitter_set_break, yaml_emitter_set_canonical, yaml_emitter_set_encoding, yaml_emitter_set_indent,
        yaml_emitter_set_output, yaml_emitter_set_output_string, yaml_emitter_set_unicode, yaml_emitter_set_width,
        yaml_event_delete, yaml_mapping_end_event_initialize, yaml_mapping_start_event_initialize, yaml_parser_delete,
        yaml_parser_initialize, yaml_parser_set_encoding, yaml_parser_set_input, yaml_parser_set_input_string,
        yaml_scalar_event_initialize, yaml_sequence_end_event_initialize, yaml_sequence_start_event_initialize,
        yaml_stream_end_event_initialize, yaml_stream_start_event_initialize, yaml_token_delete,
    },
    dumper::{yaml_emitter_close, yaml_emitter_dump, yaml_emitter_open},
    emitter::yaml_emitter_emit,
    loader::yaml_parser_load,
    parser::yaml_parser_parse,
    scanner::yaml_parser_scan,
    writer::yaml_emitter_flush,
    yaml::{
        yaml_alias_data_t, yaml_break_t, yaml_document_t, yaml_emitter_state_t, yaml_emitter_t, yaml_encoding_t,
        yaml_error_type_t, yaml_event_t, yaml_event_type_t, yaml_mapping_style_t, yaml_mark_t, yaml_node_item_t,
        yaml_node_pair_t, yaml_node_t, yaml_node_type_t, yaml_parser_state_t, yaml_parser_t, yaml_read_handler_t,
        yaml_scalar_style_t, yaml_sequence_style_t, yaml_simple_key_t, yaml_stack_t, yaml_tag_directive_t,
        yaml_token_t, yaml_token_type_t, yaml_version_directive_t, yaml_write_handler_t,
    },
};