once.rs - source

Files

addr2line

adler

aho_corasick

packed

teddy

compile.rs mod.rs runtime.rs

api.rs mod.rs pattern.rs rabinkarp.rs vector.rs

ahocorasick.rs automaton.rs buffer.rs byte_frequencies.rs classes.rs dfa.rs error.rs lib.rs nfa.rs prefilter.rs state_id.rs

ansi_term

ansi.rs debug.rs difference.rs display.rs lib.rs style.rs windows.rs write.rs

arraydeque

maybe_uninit

maybe_uninit.rs mod.rs

array.rs behavior.rs error.rs lib.rs range.rs

as_slice

atty

backtrace

backtrace

libunwind.rs mod.rs

symbolize

gimli

elf.rs mmap_unix.rs stash.rs

gimli.rs mod.rs

capture.rs lib.rs print.rs types.rs

base64

read

decoder.rs mod.rs

write

encoder.rs mod.rs

chunked_encoder.rs decode.rs display.rs encode.rs lib.rs tables.rs

bincode_core

config

endian.rs int.rs internal.rs limit.rs mod.rs trailing.rs

traits

core_read.rs core_write.rs mod.rs

buffer_writer.rs deserialize.rs lib.rs serialize.rs size_checker.rs

bitflags

byteorder

bytes

buf

ext

chain.rs limit.rs mod.rs reader.rs take.rs writer.rs

buf_impl.rs buf_mut.rs iter.rs mod.rs vec_deque.rs

fmt

debug.rs hex.rs mod.rs

bytes.rs bytes_mut.rs lib.rs loom.rs

capnp

capnp_futures

lib.rs read_stream.rs serialize.rs write_queue.rs

capnp_rpc

attach.rs broken.rs lib.rs local.rs queued.rs rpc.rs rpc_capnp.rs rpc_twoparty_capnp.rs sender_queue.rs split.rs task_set.rs twoparty.rs

cfg_if

chrono

format

mod.rs parse.rs parsed.rs scan.rs strftime.rs

naive

date.rs datetime.rs internals.rs isoweek.rs time.rs

offset

fixed.rs local.rs mod.rs utc.rs

sys

date.rs datetime.rs div.rs lib.rs round.rs sys.rs

clap

ctrlc

platform

unix

error.rs lib.rs signal.rs

derivative

ast.rs attr.rs bound.rs clone.rs cmp.rs debug.rs default.rs hash.rs lib.rs matcher.rs paths.rs utils.rs

dlib

downcast_rs

enumflags2

fallible.rs formatting.rs lib.rs

enumflags2_derive

evdev_rs

device.rs enums.rs lib.rs logging.rs macros.rs uinput.rs util.rs

evdev_sys

failure

backtrace

internal.rs mod.rs

error

error_impl.rs mod.rs

as_fail.rs box_std.rs compat.rs context.rs error_message.rs lib.rs macros.rs result_ext.rs sync_failure.rs

failure_derive

flexi_logger

writers

file_log_writer

builder.rs config.rs state.rs

file_log_writer.rs log_writer.rs

code_examples.rs deferred_now.rs flexi_error.rs flexi_logger.rs formats.rs lib.rs log_specification.rs logger.rs logger_handle.rs parameters.rs primary_writer.rs writers.rs

futures

futures_channel

mpsc

mod.rs queue.rs sink_impl.rs

lib.rs lock.rs oneshot.rs

futures_core

task

__internal

atomic_waker.rs mod.rs

future.rs lib.rs stream.rs

futures_executor

enter.rs lib.rs local_pool.rs

futures_io

futures_macro

join.rs lib.rs select.rs

futures_sink

futures_task

arc_wake.rs future_obj.rs lib.rs noop_waker.rs spawn.rs waker.rs waker_ref.rs

futures_util

async_await

join_mod.rs mod.rs pending.rs poll.rs random.rs select_mod.rs

future

io

lock

bilock.rs mod.rs mutex.rs

sink

buffer.rs close.rs drain.rs err_into.rs fanout.rs feed.rs flush.rs map_err.rs mod.rs send.rs send_all.rs unfold.rs with.rs with_flat_map.rs

stream

task

mod.rs spawn.rs

fns.rs lib.rs never.rs unfold_state.rs

generic_array

arr.rs functional.rs hex.rs impls.rs iter.rs lib.rs sequence.rs

getrandom

error.rs error_impls.rs lib.rs linux_android.rs use_file.rs util.rs util_libc.rs

gimli

glob

hash32

fnv.rs lib.rs murmur3.rs

heapless

pool

cas.rs mod.rs singleton.rs

spsc

mod.rs split.rs

binary_heap.rs histbuf.rs i.rs indexmap.rs indexset.rs lib.rs linear_map.rs mpmc.rs sealed.rs string.rs vec.rs

hid_io_core

api

capnp.rs mod.rs

device

evdev

hidapi

module

displayserver

mod.rs wayland.rs x11.rs

vhid

uhid

daemonnode.rs mod.rs

lib.rs logging.rs mailbox.rs

hid_io_protocol

commands

buffer.rs lib.rs

hidapi

error.rs ffi.rs lib.rs

install_service

install_service.rs

lazy_static

inline_lazy.rs lib.rs

libc

unix

linux_like

linux

gnu

b64

x86_64

align.rs mod.rs not_x32.rs

align.rs mod.rs

align.rs mod.rs

align.rs mod.rs

fixed_width_ints.rs lib.rs macros.rs

libloading

os

unix

consts.rs mod.rs

changelog.rs error.rs lib.rs util.rs

libudev_sys

log

lib.rs macros.rs

memchr

x86

avx.rs mod.rs sse2.rs

fallback.rs iter.rs lib.rs naive.rs

memmap

miniz_oxide

deflate

buffer.rs core.rs mod.rs stream.rs

inflate

core.rs mod.rs output_buffer.rs stream.rs

lib.rs shared.rs

mio

event

event.rs events.rs mod.rs source.rs

net

tcp

listener.rs mod.rs socket.rs stream.rs

uds

datagram.rs listener.rs mod.rs stream.rs

sys

unix

selector

epoll.rs mod.rs

uds

datagram.rs listener.rs mod.rs socketaddr.rs stream.rs

mod.rs net.rs pipe.rs sourcefd.rs tcp.rs udp.rs waker.rs

interest.rs io_source.rs lib.rs macros.rs poll.rs token.rs waker.rs

nanoid

alphabet.rs lib.rs rngs.rs

nix

num_cpus

lib.rs linux.rs

num_enum

num_enum_derive

num_integer

average.rs lib.rs roots.rs

num_traits

ops

checked.rs inv.rs mod.rs mul_add.rs overflowing.rs saturating.rs wrapping.rs

bounds.rs cast.rs float.rs identities.rs int.rs lib.rs macros.rs pow.rs sign.rs

object

once_cell

imp_std.rs lib.rs race.rs

open

pem

errors.rs lib.rs

pin_project_lite

pin_utils

lib.rs projection.rs stack_pin.rs

ppv_lite86

x86_64

lib.rs soft.rs types.rs

proc_macro2

detection.rs fallback.rs lib.rs marker.rs parse.rs wrapper.rs

proc_macro_hack

error.rs iter.rs lib.rs parse.rs quote.rs

proc_macro_nested

quote

ext.rs format.rs ident_fragment.rs lib.rs runtime.rs spanned.rs to_tokens.rs

rand

rand_chacha

chacha.rs guts.rs lib.rs

rand_core

block.rs error.rs impls.rs le.rs lib.rs os.rs

rcgen

regex

regex_syntax

remove_dir_all

ring

rustc_demangle

legacy.rs lib.rs v0.rs

rustls

scoped_tls

sct

serde

de

ignored_any.rs impls.rs mod.rs seed.rs utf8.rs value.rs

private

de.rs doc.rs mod.rs ser.rs size_hint.rs

ser

fmt.rs impls.rs impossible.rs mod.rs

integer128.rs lib.rs macros.rs

serde_derive

internals

ast.rs attr.rs case.rs check.rs ctxt.rs mod.rs receiver.rs respan.rs symbol.rs

bound.rs de.rs dummy.rs fragment.rs lib.rs pretend.rs ser.rs try.rs

slab

smallvec

spin

lib.rs mutex.rs once.rs rw_lock.rs

stable_deref_trait

strsim

syn

synstructure

lib.rs macros.rs

sys_info

tempfile

file

imp

dir.rs error.rs lib.rs spooled.rs util.rs

textwrap

indentation.rs lib.rs splitting.rs

thiserror

aserror.rs display.rs lib.rs

thiserror_impl

ast.rs attr.rs expand.rs fmt.rs lib.rs prop.rs valid.rs

time

display.rs duration.rs lib.rs parse.rs sys.rs

tokio

future

block_on.rs maybe_done.rs mod.rs poll_fn.rs ready.rs

io

driver

interest.rs mod.rs ready.rs registration.rs scheduled_io.rs

async_buf_read.rs async_fd.rs async_read.rs async_seek.rs async_write.rs mod.rs poll_evented.rs read_buf.rs

loom

std

atomic_ptr.rs atomic_u16.rs atomic_u32.rs atomic_u64.rs atomic_u8.rs atomic_usize.rs mod.rs mutex.rs unsafe_cell.rs

macros

cfg.rs join.rs loom.rs mod.rs pin.rs ready.rs scoped_tls.rs select.rs support.rs thread_local.rs try_join.rs

net

park

either.rs mod.rs thread.rs

runtime

stream

sync

mpsc

block.rs bounded.rs chan.rs error.rs list.rs mod.rs unbounded.rs

task

atomic_waker.rs mod.rs

barrier.rs batch_semaphore.rs broadcast.rs mod.rs mutex.rs notify.rs oneshot.rs rwlock.rs semaphore.rs watch.rs

task

blocking.rs local.rs mod.rs spawn.rs task_local.rs yield_now.rs

time

driver

wheel

level.rs mod.rs

entry.rs handle.rs mod.rs sleep.rs

clock.rs error.rs instant.rs interval.rs mod.rs timeout.rs

util

bit.rs linked_list.rs mod.rs rand.rs slab.rs trace.rs try_lock.rs wake.rs

blocking.rs coop.rs lib.rs prelude.rs

tokio_macros

entry.rs lib.rs select.rs

tokio_rustls

common

handshake.rs mod.rs

client.rs lib.rs server.rs

tokio_util

sync

cancellation_token.rs intrusive_double_linked_list.rs mod.rs

cfg.rs compat.rs either.rs lib.rs loom.rs

typenum

array.rs bit.rs int.rs lib.rs marker_traits.rs operator_aliases.rs private.rs type_operators.rs uint.rs

udev

device.rs enumerator.rs lib.rs monitor.rs udev.rs util.rs

uhid_virt

codec.rs lib.rs uhid_device.rs

uhidrs_sys

unicode_width

lib.rs tables.rs

unicode_xid

lib.rs tables.rs

untrusted

vec_map

wayland_client

native_lib

display.rs event_queue.rs mod.rs proxy.rs

display.rs event_queue.rs globals.rs lib.rs proxy.rs

wayland_commons

debug.rs filter.rs lib.rs map.rs socket.rs user_data.rs wire.rs

wayland_sys

client.rs common.rs lib.rs server.rs

webpki

calendar.rs cert.rs der.rs error.rs name.rs signed_data.rs time.rs trust_anchor_util.rs verify_cert.rs webpki.rs

which

checker.rs error.rs finder.rs lib.rs

x11

dpms.rs glx.rs internal.rs keysym.rs lib.rs link.rs xcursor.rs xf86vmode.rs xfixes.rs xft.rs xinerama.rs xinput.rs xinput2.rs xlib.rs xlib_xcb.rs xmd.rs xmu.rs xrandr.rs xrecord.rs xrender.rs xss.rs xt.rs xtest.rs

xcb

ffi

base.rs big_requests.rs xc_misc.rs xkb.rs xproto.rs

base.rs big_requests.rs lib.rs xc_misc.rs xkb.rs xproto.rs

xkbcommon

xkb

x11

compose.rs ffi.rs keysyms.rs mod.rs

yansi

color.rs docify.rs lib.rs macros.rs paint.rs style.rs windows.rs

yasna

deserializer

models

der.rs mod.rs oid.rs time.rs

reader

error.rs mod.rs

serializer

tags

writer

zwp_virtual_keyboard

use crate::stream::{self, Iter, Stream};

use core::option;
use core::pin::Pin;
use core::task::{Context, Poll};

/// Stream for the [`once`](fn@once) function.
#[derive(Debug)]
#[must_use = "streams do nothing unless polled"]
pub struct Once<T> {
    iter: Iter<option::IntoIter<T>>,
}

impl<I> Unpin for Once<I> {}

/// Creates a stream that emits an element exactly once.
///
/// The returned stream is immediately ready and emits the provided value once.
///
/// # Examples
///
/// ```
/// use tokio::stream::{self, StreamExt};
///
/// #[tokio::main]
/// async fn main() {
///     // one is the loneliest number
///     let mut one = stream::once(1);
///
///     assert_eq!(Some(1), one.next().await);
///
///     // just one, that's all we get
///     assert_eq!(None, one.next().await);
/// }
/// ```
pub fn once<T>(value: T) -> Once<T> {
    Once {
        iter: stream::iter(Some(value).into_iter()),
    }
}

impl<T> Stream for Once<T> {
    type Item = T;

    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<T>> {
        Pin::new(&mut self.iter).poll_next(cx)
    }

    fn size_hint(&self) -> (usize, Option<usize>) {
        self.iter.size_hint()
    }
}