libwasm/src/io.rs

145 lines
3.9 KiB
Rust

//! This module provides cross platform I/O facilities. It takes inspiration from the Rust `std::io` module,
//! and uses that for platform support outside of ableOS.
//! One day, we might hope for this module to be superseded by real `std` support for ableOS.
use ::std::io::{self, Read, BufRead, BufReader, IoSliceMut};
/// Print a string to the console.
fn print(x: &str) {
#[cfg(ableOS)] {
extern "C" {
fn print_char(x: u32);
}
fn print_byte(x: u8) {
unsafe { print_char(x as u32) }
}
for b in x.bytes() {
print_byte(b);
}
}
#[cfg(not(ableOS))] {
print!("{}", x)
}
}
/// Like [`print`], but starts a new line after.
pub fn println(x: &str) {
print(x);
print("\n");
}
/// Like [`println`], but meant to print to a standard error output.
pub fn eprintln(x: &str) {
#[cfg(ableOS)] {
println(x);
}
#[cfg(not(ableOS))] {
eprintln!("{}", x)
}
}
#[cfg(ableOS)]
static STDIN: ::once_cell::sync::Lazy<::std::sync::Mutex<BufReader<AbleStdinRaw>>> = ::once_cell::sync::Lazy::new(|| {
::std::sync::Mutex::new(BufReader::new(AbleStdinRaw))
});
#[cfg(ableOS)]
struct AbleStdinRaw;
#[cfg(ableOS)]
impl Read for AbleStdinRaw {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
// TODO: detect EOF
loop {
let chr = unsafe { crate::syscalls::get_input() };
if chr != 0 {
break Ok(char::from_u32(chr as u32).unwrap().encode_utf8(buf).len())
}
}
}
}
/// A handle to the standard input stream of the process.
/// See [`Stdin`](::std::io::Stdin) for roughly how this should be treated.
pub struct Stdin {
#[cfg(ableOS)]
inner: &'static ::std::sync::Mutex<BufReader<AbleStdinRaw>>,
#[cfg(not(ableOS))]
inner: io::Stdin,
}
impl Stdin {
pub fn lock(&self) -> StdinLock<'_> {
#[cfg(ableOS)] {
StdinLock {
inner: self.inner.lock().unwrap()
}
}
#[cfg(not(ableOS))] {
StdinLock {
inner: self.inner.lock(),
}
}
}
}
/// A locked reference to the [`Stdin`] handle.
/// See [`StdinLock`](::std::io::StdinLock) for roughly how this should be treated.
pub struct StdinLock<'a> {
#[cfg(ableOS)]
inner: ::std::sync::MutexGuard<'a, BufReader<AbleStdinRaw>>,
#[cfg(not(ableOS))]
inner: io::StdinLock<'a>,
}
impl<'a> BufRead for StdinLock<'_> {
fn fill_buf(&mut self) -> io::Result<&[u8]> {
self.inner.fill_buf()
}
fn consume(&mut self, n: usize) {
self.inner.consume(n)
}
fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
self.inner.read_until(byte, buf)
}
fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
self.inner.read_line(buf)
}
}
impl Read for StdinLock<'_> {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
self.inner.read(buf)
}
fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
self.inner.read_vectored(bufs)
}
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
self.inner.read_to_end(buf)
}
fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
self.inner.read_to_string(buf)
}
fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
self.inner.read_exact(buf)
}
}
/// Constructs a new handle to the standard input of the current process.
/// Each handle returned is a reference to a shared global buffer whose access is synchronized via a mutex.
/// If you need more explicit control over locking, see the [`Stdin::lock`] method.
pub fn stdin() -> Stdin {
#[cfg(ableOS)] {
Stdin {
inner: &STDIN
}
}
#[cfg(not(ableOS))] {
Stdin {
inner: ::std::io::stdin(),
}
}
}