Files
aho_corasick
ansi_term
arrayvec
atty
backtrace
backtrace_sys
base64
bincode
bitflags
byteorder
bytes
c2_chacha
capnp
capnp_futures
capnp_rpc
cfg_if
chrono
clap
crossbeam_deque
crossbeam_epoch
crossbeam_queue
crossbeam_utils
ctrlc
daemon
failure
failure_derive
flexi_logger
fnv
futures
getrandom
glob
hid_io
api
device
module
protocol
hidapi
install_service
iovec
lazy_static
libc
lock_api
log
memchr
memoffset
mio
mio_uds
nanoid
net2
nix
nodrop
num_cpus
num_integer
num_traits
open
parking_lot
parking_lot_core
pem
ppv_lite86
proc_macro2
quote
rand
rand_chacha
rand_core
rand_hc
rand_isaac
rand_jitter
rand_os
rand_pcg
rand_xorshift
rcgen
regex
regex_syntax
remove_dir_all
ring
rustc_demangle
rustls
scoped_tls
scopeguard
sct
serde
slab
smallvec
spin
stream_cancel
strsim
syn
synstructure
tempfile
textwrap
thread_local
time
tokio
tokio_codec
tokio_core
tokio_current_thread
tokio_executor
tokio_fs
tokio_io
tokio_reactor
tokio_rustls
tokio_sync
tokio_tcp
tokio_threadpool
tokio_timer
tokio_udp
tokio_uds
unicode_width
unicode_xid
untrusted
vec_map
void
webpki
windows_service
x11
xcb
xkbcommon
yasna
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
use {Future, Poll, Async};
use future::Either;

/// Future for the `select2` combinator, waiting for one of two differently-typed
/// futures to complete.
///
/// This is created by the [`Future::select2`] method.
///
/// [`Future::select2`]: trait.Future.html#method.select2
#[must_use = "futures do nothing unless polled"]
#[derive(Debug)]
pub struct Select2<A, B> {
    inner: Option<(A, B)>,
}

pub fn new<A, B>(a: A, b: B) -> Select2<A, B> {
    Select2 { inner: Some((a, b)) }
}

impl<A, B> Future for Select2<A, B> where A: Future, B: Future {
    type Item = Either<(A::Item, B), (B::Item, A)>;
    type Error = Either<(A::Error, B), (B::Error, A)>;

    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
        let (mut a, mut b) = self.inner.take().expect("cannot poll Select2 twice");
        match a.poll() {
            Err(e) => Err(Either::A((e, b))),
            Ok(Async::Ready(x)) => Ok(Async::Ready(Either::A((x, b)))),
            Ok(Async::NotReady) => match b.poll() {
                Err(e) => Err(Either::B((e, a))),
                Ok(Async::Ready(x)) => Ok(Async::Ready(Either::B((x, a)))),
                Ok(Async::NotReady) => {
                    self.inner = Some((a, b));
                    Ok(Async::NotReady)
                }
            }
        }
    }
}