276 lines
7.5 KiB
Rust
276 lines
7.5 KiB
Rust
mod pipes {
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import unsafe::{forget, reinterpret_cast};
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enum state {
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empty,
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full,
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blocked,
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terminated
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}
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type packet<T: send> = {
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mut state: state,
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mut blocked_task: option<task::Task>,
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mut payload: option<T>
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};
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fn packet<T: send>() -> *packet<T> unsafe {
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let p: *packet<T> = unsafe::transmute(~{
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mut state: empty,
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mut blocked_task: none::<task::Task>,
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mut payload: none::<T>
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});
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p
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}
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#[abi = "rust-intrinsic"]
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mod rusti {
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fn atomic_xchng(&dst: int, src: int) -> int { fail; }
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fn atomic_xchng_acq(&dst: int, src: int) -> int { fail; }
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fn atomic_xchng_rel(&dst: int, src: int) -> int { fail; }
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}
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// We should consider moving this to core::unsafe, although I
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// suspect graydon would want us to use void pointers instead.
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unsafe fn uniquify<T>(x: *T) -> ~T {
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unsafe { unsafe::reinterpret_cast(x) }
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}
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fn swap_state_acq(&dst: state, src: state) -> state {
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unsafe {
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reinterpret_cast(rusti::atomic_xchng_acq(
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*(ptr::mut_addr_of(dst) as *mut int),
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src as int))
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}
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}
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fn swap_state_rel(&dst: state, src: state) -> state {
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unsafe {
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reinterpret_cast(rusti::atomic_xchng_rel(
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*(ptr::mut_addr_of(dst) as *mut int),
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src as int))
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}
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}
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fn send<T: send>(-p: send_packet<T>, -payload: T) {
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let p = p.unwrap();
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let p = unsafe { uniquify(p) };
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assert (*p).payload == none;
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(*p).payload <- some(payload);
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let old_state = swap_state_rel((*p).state, full);
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match old_state {
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empty => {
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// Yay, fastpath.
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// The receiver will eventually clean this up.
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unsafe { forget(p); }
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}
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full => { fail ~"duplicate send" }
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blocked => {
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// The receiver will eventually clean this up.
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unsafe { forget(p); }
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}
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terminated => {
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// The receiver will never receive this. Rely on drop_glue
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// to clean everything up.
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}
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}
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}
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fn recv<T: send>(-p: recv_packet<T>) -> option<T> {
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let p = p.unwrap();
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let p = unsafe { uniquify(p) };
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loop {
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let old_state = swap_state_acq((*p).state,
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blocked);
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match old_state {
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empty | blocked => { task::yield(); }
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full => {
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let mut payload = none;
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payload <-> (*p).payload;
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return some(option::unwrap(payload))
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}
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terminated => {
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assert old_state == terminated;
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return none;
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}
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}
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}
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}
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fn sender_terminate<T: send>(p: *packet<T>) {
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let p = unsafe { uniquify(p) };
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match swap_state_rel((*p).state, terminated) {
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empty | blocked => {
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// The receiver will eventually clean up.
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unsafe { forget(p) }
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}
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full => {
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// This is impossible
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fail ~"you dun goofed"
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}
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terminated => {
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// I have to clean up, use drop_glue
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}
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}
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}
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fn receiver_terminate<T: send>(p: *packet<T>) {
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let p = unsafe { uniquify(p) };
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match swap_state_rel((*p).state, terminated) {
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empty => {
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// the sender will clean up
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unsafe { forget(p) }
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}
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blocked => {
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// this shouldn't happen.
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fail ~"terminating a blocked packet"
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}
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terminated | full => {
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// I have to clean up, use drop_glue
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}
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}
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}
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class send_packet<T: send> {
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let mut p: option<*packet<T>>;
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new(p: *packet<T>) { self.p = some(p); }
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drop {
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if self.p != none {
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let mut p = none;
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p <-> self.p;
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sender_terminate(option::unwrap(p))
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}
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}
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fn unwrap() -> *packet<T> {
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let mut p = none;
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p <-> self.p;
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option::unwrap(p)
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}
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}
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class recv_packet<T: send> {
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let mut p: option<*packet<T>>;
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new(p: *packet<T>) { self.p = some(p); }
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drop {
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if self.p != none {
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let mut p = none;
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p <-> self.p;
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receiver_terminate(option::unwrap(p))
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}
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}
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fn unwrap() -> *packet<T> {
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let mut p = none;
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p <-> self.p;
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option::unwrap(p)
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}
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}
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fn entangle<T: send>() -> (send_packet<T>, recv_packet<T>) {
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let p = packet();
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(send_packet(p), recv_packet(p))
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}
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}
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mod pingpong {
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enum ping = pipes::send_packet<pong>;
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enum pong = pipes::send_packet<ping>;
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fn liberate_ping(-p: ping) -> pipes::send_packet<pong> unsafe {
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let addr : *pipes::send_packet<pong> = match p {
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ping(x) => { unsafe::reinterpret_cast(ptr::addr_of(x)) }
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};
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let liberated_value <- *addr;
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unsafe::forget(p);
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liberated_value
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}
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fn liberate_pong(-p: pong) -> pipes::send_packet<ping> unsafe {
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let addr : *pipes::send_packet<ping> = match p {
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pong(x) => { unsafe::reinterpret_cast(ptr::addr_of(x)) }
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};
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let liberated_value <- *addr;
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unsafe::forget(p);
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liberated_value
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}
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fn init() -> (client::ping, server::ping) {
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pipes::entangle()
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}
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mod client {
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type ping = pipes::send_packet<pingpong::ping>;
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type pong = pipes::recv_packet<pingpong::pong>;
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fn do_ping(-c: ping) -> pong {
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let (sp, rp) = pipes::entangle();
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pipes::send(c, ping(sp));
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rp
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}
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fn do_pong(-c: pong) -> (ping, ()) {
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let packet = pipes::recv(c);
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if packet == none {
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fail ~"sender closed the connection"
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}
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(liberate_pong(option::unwrap(packet)), ())
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}
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}
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mod server {
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type ping = pipes::recv_packet<pingpong::ping>;
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type pong = pipes::send_packet<pingpong::pong>;
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fn do_ping(-c: ping) -> (pong, ()) {
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let packet = pipes::recv(c);
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if packet == none {
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fail ~"sender closed the connection"
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}
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(liberate_ping(option::unwrap(packet)), ())
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}
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fn do_pong(-c: pong) -> ping {
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let (sp, rp) = pipes::entangle();
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pipes::send(c, pong(sp));
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rp
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}
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}
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}
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fn client(-chan: pingpong::client::ping) {
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let chan = pingpong::client::do_ping(chan);
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log(error, ~"Sent ping");
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let (chan, _data) = pingpong::client::do_pong(chan);
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log(error, ~"Received pong");
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}
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fn server(-chan: pingpong::server::ping) {
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let (chan, _data) = pingpong::server::do_ping(chan);
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log(error, ~"Received ping");
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let chan = pingpong::server::do_pong(chan);
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log(error, ~"Sent pong");
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}
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fn main() {
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/*
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// Commented out because of option::get error
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let (client_, server_) = pingpong::init();
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let client_ = ~mut some(client_);
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let server_ = ~mut some(server_);
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task::spawn {|move client_|
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let mut client__ = none;
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*client_ <-> client__;
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client(option::unwrap(client__));
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};
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task::spawn {|move server_|
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let mut server_ˊ = none;
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*server_ <-> server_ˊ;
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server(option::unwrap(server_ˊ));
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};
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*/
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}
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