90 lines
3.0 KiB
Rust
90 lines
3.0 KiB
Rust
use core::ops::{Deref, DerefMut};
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#[cfg(feature = "socket-raw")]
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use crate::socket::RawSocket;
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#[cfg(all(feature = "socket-icmp", any(feature = "proto-ipv4", feature = "proto-ipv6")))]
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use crate::socket::IcmpSocket;
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#[cfg(feature = "socket-udp")]
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use crate::socket::UdpSocket;
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#[cfg(feature = "socket-tcp")]
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use crate::socket::TcpSocket;
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/// A trait for tracking a socket usage session.
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///
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/// Allows implementation of custom drop logic that runs only if the socket was changed
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/// in specific ways. For example, drop logic for UDP would check if the local endpoint
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/// has changed, and if yes, notify the socket set.
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#[doc(hidden)]
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pub trait Session {
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fn finish(&mut self) {}
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}
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#[cfg(feature = "socket-raw")]
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impl<'a, 'b> Session for RawSocket<'a, 'b> {}
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#[cfg(all(feature = "socket-icmp", any(feature = "proto-ipv4", feature = "proto-ipv6")))]
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impl<'a, 'b> Session for IcmpSocket<'a, 'b> {}
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#[cfg(feature = "socket-udp")]
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impl<'a, 'b> Session for UdpSocket<'a, 'b> {}
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#[cfg(feature = "socket-tcp")]
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impl<'a> Session for TcpSocket<'a> {}
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/// A smart pointer to a socket.
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///
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/// Allows the network stack to efficiently determine if the socket state was changed in any way.
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pub struct Ref<'a, T: Session + 'a> {
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/// Reference to the socket.
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///
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/// This is almost always `Some` except when dropped in `into_inner` which removes the socket
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/// reference. This properly tracks the initialization state without any additional bytes as
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/// the `None` variant occupies the `0` pattern which is invalid for the reference.
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socket: Option<&'a mut T>,
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}
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impl<'a, T: Session + 'a> Ref<'a, T> {
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/// Wrap a pointer to a socket to make a smart pointer.
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///
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/// Calling this function is only necessary if your code is using [into_inner].
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///
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/// [into_inner]: #method.into_inner
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pub fn new(socket: &'a mut T) -> Self {
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Ref { socket: Some(socket) }
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}
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/// Unwrap a smart pointer to a socket.
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///
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/// The finalization code is not run. Prompt operation of the network stack depends
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/// on wrapping the returned pointer back and dropping it.
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///
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/// Calling this function is only necessary to achieve composability if you *must*
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/// map a `&mut SocketRef<'a, XSocket>` to a `&'a mut XSocket` (note the lifetimes);
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/// be sure to call [new] afterwards.
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///
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/// [new]: #method.new
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pub fn into_inner(mut ref_: Self) -> &'a mut T {
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ref_.socket.take().unwrap()
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}
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}
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impl<'a, T: Session> Deref for Ref<'a, T> {
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type Target = T;
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fn deref(&self) -> &Self::Target {
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// Deref is only used while the socket is still in place (into inner has not been called).
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self.socket.as_ref().unwrap()
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}
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}
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impl<'a, T: Session> DerefMut for Ref<'a, T> {
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fn deref_mut(&mut self) -> &mut Self::Target {
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self.socket.as_mut().unwrap()
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}
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}
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impl<'a, T: Session> Drop for Ref<'a, T> {
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fn drop(&mut self) {
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if let Some(socket) = self.socket.take() {
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Session::finish(socket);
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}
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}
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}
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