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// Copyright 2016 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//! Type-safe bindings for Zircon sockets.
use {AsHandleRef, HandleBased, Handle, HandleRef, Peered};
use {sys, Status, ok};
use std::ptr;
/// An object representing a Zircon
/// [socket](https://fuchsia.googlesource.com/zircon/+/master/docs/concepts.md#Message-Passing_Sockets-and-Channels).
///
/// As essentially a subtype of `Handle`, it can be freely interconverted.
#[derive(Debug, Eq, PartialEq)]
pub struct Socket(Handle);
impl_handle_based!(Socket);
impl Peered for Socket {}
impl Socket {
/// Create a socket, accessed through a pair of endpoints. Data written
/// into one may be read from the other.
///
/// Wraps
/// [zx_socket_create](https://fuchsia.googlesource.com/zircon/+/master/docs/syscalls/socket_create.md).
pub fn create() -> Result<(Socket, Socket), Status> {
unsafe {
let mut out0 = 0;
let mut out1 = 0;
let opts = 0;
let status = sys::zx_socket_create(opts, &mut out0, &mut out1);
ok(status)?;
Ok((
Self::from(Handle::from_raw(out0)),
Self::from(Handle::from_raw(out1))
))
}
}
/// Write the given bytes into the socket.
/// Return value (on success) is number of bytes actually written.
///
/// Wraps
/// [zx_socket_write](https://fuchsia.googlesource.com/zircon/+/master/docs/syscalls/socket_write.md).
pub fn write(&self, bytes: &[u8]) -> Result<usize, Status> {
let mut actual = 0;
let opts = 0;
let status = unsafe {
sys::zx_socket_write(self.raw_handle(), opts, bytes.as_ptr(), bytes.len(),
&mut actual)
};
ok(status).map(|()| actual)
}
/// Read the given bytes from the socket.
/// Return value (on success) is number of bytes actually read.
///
/// Wraps
/// [zx_socket_read](https://fuchsia.googlesource.com/zircon/+/master/docs/syscalls/socket_read.md).
pub fn read(&self, bytes: &mut [u8]) -> Result<usize, Status> {
let mut actual = 0;
let opts = 0;
let status = unsafe {
sys::zx_socket_read(self.raw_handle(), opts, bytes.as_mut_ptr(),
bytes.len(), &mut actual)
};
ok(status)
.map(|()| actual)
.map_err(|status| {
// If an error is returned then actual is undefined, so to be safe
// we set it to 0 and ignore any data that is set in bytes.
actual = 0;
status
})
}
/// Close half of the socket, so attempts by the other side to write will fail.
///
/// Implements the `ZX_SOCKET_HALF_CLOSE` option of
/// [zx_socket_write](https://fuchsia.googlesource.com/zircon/+/master/docs/syscalls/socket_write.md).
pub fn half_close(&self) -> Result<(), Status> {
let status = unsafe { sys::zx_socket_write(self.raw_handle(), sys::ZX_SOCKET_HALF_CLOSE,
ptr::null(), 0, ptr::null_mut()) };
ok(status)
}
pub fn outstanding_read_bytes(&self) -> Result<usize, Status> {
let mut outstanding = 0;
let status = unsafe {
sys::zx_socket_read(self.raw_handle(), 0, ptr::null_mut(), 0, &mut outstanding)
};
ok(status).map(|()| outstanding)
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn socket_basic() {
let (s1, s2) = Socket::create().unwrap();
// Write in one end and read it back out the other.
assert_eq!(s1.write(b"hello").unwrap(), 5);
let mut read_vec = vec![0; 8];
assert_eq!(s2.read(&mut read_vec).unwrap(), 5);
assert_eq!(&read_vec[0..5], b"hello");
// Try reading when there is nothing to read.
assert_eq!(s2.read(&mut read_vec), Err(Status::SHOULD_WAIT));
// Close the socket from one end.
assert!(s1.half_close().is_ok());
assert_eq!(s2.read(&mut read_vec), Err(Status::BAD_STATE));
assert_eq!(s1.write(b"fail"), Err(Status::BAD_STATE));
// Writing in the other direction should still work.
assert_eq!(s1.read(&mut read_vec), Err(Status::SHOULD_WAIT));
assert_eq!(s2.write(b"back").unwrap(), 4);
assert_eq!(s1.read(&mut read_vec).unwrap(), 4);
assert_eq!(&read_vec[0..4], b"back");
}
}