parent
3d157e51d8
commit
afa1d93212
GPG Key ID:
284488987C31F630
@ -0,0 +1,150 @@
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//! Errno handling
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use super::*;
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use std::{
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error,
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fmt,
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};
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use libc::__errno_location;
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use once_cell::sync::OnceCell;
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const MESSAGE_BUF_SIZE: usize = 512;
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/// Get `errno` value.
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#[inline] pub fn raw() -> i32
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{
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unsafe{*__errno_location()}
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}
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fn get_message(errno: i32) -> String
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{
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use libc::{
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strerror_r,
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};
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use std::ffi::CStr;
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let mut buffer = [0u8; MESSAGE_BUF_SIZE+1];
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let cstr = unsafe {
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strerror_r(errno, &mut buffer[0] as *mut u8 as *mut libc::c_char, MESSAGE_BUF_SIZE);
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CStr::from_ptr(&buffer[0] as *const u8 as *const libc::c_char)
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};
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cstr.to_string_lossy().into_owned()
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}
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#[derive(Debug)]
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/// Errno wrapper for Rust errors
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pub struct Errno<T>
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where T: fmt::Debug
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{
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errno: i32,
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msg: OnceCell<String>,
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pub internal: T,
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}
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impl<T> Errno<T>
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where T: error::Error + 'static
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{
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/// Get the message for this errno
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pub fn message(&self) -> &str
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{
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&self.msg.get_or_init(|| get_message(self.errno))[..]
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}
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/// Get the errno of this instance
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pub fn error(&self) -> i32
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{
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self.errno
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}
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/// Consume this instance, returning the wrapped value
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pub fn into_inner(self) -> T
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{
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self.internal
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}
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/// Map the inner value
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pub fn map_inner<U,F>(self, fun: F) -> Errno<U>
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where F: FnOnce(T) -> U,
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U: error::Error + 'static
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{
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Errno {
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internal: fun(self.internal),
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errno: self.errno,
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msg: self.msg,
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}
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}
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/// Check if this `errno` value is 0 (`Success`)
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pub fn is_success(&self) -> bool
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{
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self.errno == 0
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}
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}
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impl<T> std::error::Error for Errno<T>
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where T: error::Error + 'static
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{
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fn source(&self) -> Option<&(dyn error::Error + 'static)>
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{
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Some(&self.internal)
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}
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}
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impl<T> std::fmt::Display for Errno<T>
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where T: error::Error + 'static
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{
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
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{
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write!(f, "{}: {} ({})", self.internal, self.message(), self.errno)
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}
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}
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impl<T> Errno<T>
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where T: error::Error + 'static
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{
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/// Create a new errno wrapper with specific `errno` value
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pub fn with_errno(err: T, errno: i32) -> Self
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{
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Self {
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errno,
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msg: OnceCell::new(),
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internal: err
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}
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}
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/// Create a new errno wrapper with the current `errno` value
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#[inline] pub fn new(err: T) -> Self
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{
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Self::with_errno(err, raw())
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}
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}
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impl<T> From<T> for Errno<T>
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where T: error::Error + 'static
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{
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#[inline] fn from(from: T) -> Self
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{
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Self::new(from)
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}
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}
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pub trait ResultExt<T,V>
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{
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/// Call `map_inner()` on the inner error of `Errno<T>` if it is `Err`, otherwise return the same `Ok`.
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fn map_inner<U,F>(self, fun: F) -> Result<V,Errno<U>>
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where F: FnOnce(T) -> U,
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U: error::Error + 'static;
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}
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impl<T,V> ResultExt<T,V> for Result<V,Errno<T>>
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where T: error::Error + 'static
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{
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fn map_inner<U,F>(self, fun: F) -> Result<V,Errno<U>>
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where F: FnOnce(T) -> U,
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U: error::Error + 'static
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{
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self.map_err(|e| e.map_inner(fun))
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}
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}
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@ -1,3 +1,105 @@
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//! `pipe()` wrapper
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//! `pipe()` related operations
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use super::*;
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use errno::Errno;
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use std::{
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fmt,
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};
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/// Represents an error on `pipe()` related operations
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#[derive(Debug)]
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pub enum Error {
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Create,
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Read,
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Write,
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Broken,
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Unknown,
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}
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impl std::error::Error for Error{}
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impl std::fmt::Display for Error
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{
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
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{
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match self {
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Self::Create => write!(f, "failed to create pipe"),
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Self::Read => write!(f, "failed to read from pipe"),
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Self::Write => write!(f, "failed to write to pipe"),
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Self::Broken => write!(f, "broken pipe"),
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_ => write!(f, "unknown error"),
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}
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}
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}
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/// Create with `pipe()`
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pub(super) fn unix_pipe() -> Result<(i32,i32), Errno<Error>>
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{
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use libc::{
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pipe,
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};
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let mut pipe_fd: [libc::c_int; 2] = [0;2];
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if unsafe{pipe(&mut pipe_fd[0] as *mut libc::c_int)} == 0{
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Ok((pipe_fd[0], pipe_fd[1]))
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} else {
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Err(Error::Create.into())
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}
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}
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/// Write to a pipe
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pub(super) fn pipe_write(output: i32, buf: impl AsRef<[u8]>) -> Result<usize, Errno<Error>>
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{
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let buf = buf.as_ref();
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let len = buf.len();
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let read = unsafe{libc::write(output, &buf[0] as *const u8 as *const libc::c_void, len)};
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if read < 0 {
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Err(Error::Write.into())
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} else {
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Ok(read as usize)
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}
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}
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pub(super) fn pipe_read(input: i32, mut buf: impl AsMut<[u8]>) -> Result<usize, Errno<Error>>
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{
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let buf = buf.as_mut();
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let len = buf.len();
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let read = unsafe{libc::read(input, &mut buf[0] as *mut u8 as *mut libc::c_void, len)};
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if read < 0 {
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Err(Error::Read.into())
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} else {
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Ok(read as usize)
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}
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}
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pub(super) unsafe fn pipe_write_value<T: ?Sized>(fd: i32, value: &T) -> Result<(), Errno<Error>>
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{
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let sz = std::mem::size_of_val(value);
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let write = pipe_write(fd, std::slice::from_raw_parts(value as *const T as *const u8, sz))?;
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if write == sz {
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Ok(())
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} else {
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Err(Error::Broken.into())
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}
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}
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pub(super) unsafe fn pipe_read_value<T>(fd: i32) -> Result<T, Errno<Error>>
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{
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use malloc_array::heap;
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let mut buf = heap![unsafe 0u8; std::mem::size_of::<T>()];
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let read = pipe_read(fd, &mut buf)?;
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if read == buf.len() {
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let ptr = buf.reinterpret::<T>();
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Ok(ptr.as_ptr().read())
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} else {
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Err(Error::Broken.into())
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}
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}
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