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// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![unstable(reason = "not public", issue = "0", feature = "fd")]
use cmp;
use io::{self, Read};
use libc::{self, c_int, c_void, ssize_t};
use mem;
use sys::cvt;
use sys_common::AsInner;
use sys_common::io::read_to_end_uninitialized;
#[derive(Debug)]
pub struct FileDesc {
fd: c_int,
}
fn max_len() -> usize {
// The maximum read limit on most posix-like systems is `SSIZE_MAX`,
// with the man page quoting that if the count of bytes to read is
// greater than `SSIZE_MAX` the result is "unspecified".
//
// On OSX, however, apparently the 64-bit libc is either buggy or
// intentionally showing odd behavior by rejecting any read with a size
// larger than or equal to INT_MAX. To handle both of these the read
// size is capped on both platforms.
if cfg!(target_os = "macos") {
<c_int>::max_value() as usize - 1
} else {
<ssize_t>::max_value() as usize
}
}
impl FileDesc {
pub fn new(fd: c_int) -> FileDesc {
FileDesc { fd: fd }
}
pub fn raw(&self) -> c_int { self.fd }
/// Extracts the actual filedescriptor without closing it.
pub fn into_raw(self) -> c_int {
let fd = self.fd;
mem::forget(self);
fd
}
pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> {
let ret = cvt(unsafe {
libc::read(self.fd,
buf.as_mut_ptr() as *mut c_void,
cmp::min(buf.len(), max_len()))
})?;
Ok(ret as usize)
}
pub fn read_to_end(&self, buf: &mut Vec<u8>) -> io::Result<usize> {
let mut me = self;
(&mut me).read_to_end(buf)
}
pub fn read_at(&self, buf: &mut [u8], offset: u64) -> io::Result<usize> {
unsafe fn cvt_pread64(fd: c_int, buf: *mut c_void, count: usize, offset: i64)
-> io::Result<isize>
{
use libc::pread as pread64;
cvt(pread64(fd, buf, count, offset))
}
unsafe {
cvt_pread64(self.fd,
buf.as_mut_ptr() as *mut c_void,
cmp::min(buf.len(), max_len()),
offset as i64)
.map(|n| n as usize)
}
}
pub fn write(&self, buf: &[u8]) -> io::Result<usize> {
let ret = cvt(unsafe {
libc::write(self.fd,
buf.as_ptr() as *const c_void,
cmp::min(buf.len(), max_len()))
})?;
Ok(ret as usize)
}
pub fn write_at(&self, buf: &[u8], offset: u64) -> io::Result<usize> {
unsafe fn cvt_pwrite64(fd: c_int, buf: *const c_void, count: usize, offset: i64)
-> io::Result<isize>
{
use libc::pwrite as pwrite64;
cvt(pwrite64(fd, buf, count, offset))
}
unsafe {
cvt_pwrite64(self.fd,
buf.as_ptr() as *const c_void,
cmp::min(buf.len(), max_len()),
offset as i64)
.map(|n| n as usize)
}
}
// This is a unix-specific operation that the 3DS likely doesn't support.
// However, there's no reason to make calling this function an error either.
pub fn set_cloexec(&self) -> io::Result<()> {
Ok(())
}
// This is a unix-specific operation that the 3DS likely doesn't support.
// However, there's no reason to make calling this function an error either.
pub fn set_nonblocking(&self) -> io::Result<()> {
Ok(())
}
// The sdmc and romfs devoptabs definitely don't support this operation.
// Not sure if it will be needed for network support or not.
pub fn duplicate(&self) -> io::Result<FileDesc> {
unimplemented!()
}
}
impl<'a> Read for &'a FileDesc {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
(**self).read(buf)
}
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
unsafe { read_to_end_uninitialized(self, buf) }
}
}
impl AsInner<c_int> for FileDesc {
fn as_inner(&self) -> &c_int { &self.fd }
}
impl Drop for FileDesc {
fn drop(&mut self) {
// Note that errors are ignored when closing a file descriptor. The
// reason for this is that if an error occurs we don't actually know if
// the file descriptor was closed or not, and if we retried (for
// something like EINTR), we might close another valid file descriptor
// (opened after we closed ours.
let _ = unsafe { libc::close(self.fd) };
}
}
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