option.rs.html -- source

Files

addr2line

ahash

convert.rs fallback_hash.rs lib.rs

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

arrayref

arrayvec

array.rs array_string.rs char.rs errors.rs lib.rs maybe_uninit_stable.rs range.rs

artemis_asset

artemis_core

lib.rs registry.rs types.rs

artemis_erc20_app

lib.rs payload.rs

artemis_eth_app

lib.rs payload.rs

artemis_ethereum

backtrace

backtrace

libunwind.rs mod.rs

symbolize

gimli

elf.rs mmap_unix.rs

gimli.rs mod.rs

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

base58

bip39

crypto.rs error.rs language.rs lib.rs mnemonic.rs mnemonic_type.rs seed.rs util.rs

bitmask

bitvec

blake2_rfc

simd_opt

as_bytes.rs blake2.rs blake2b.rs blake2s.rs bytes.rs lib.rs simd.rs simdint.rs simdop.rs simdty.rs

block_buffer

block_padding

byte_slice_cast

byte_tools

byteorder

cfg_if

clear_on_drop

clear.rs clear_on_drop.rs clear_stack_on_return.rs fnoption.rs hide.rs lib.rs

const_random

const_random_macro

constant_time_eq

crunchy

crypto_mac

errors.rs lib.rs

curve25519_dalek

backend

serial

curve_models

scalar_mul

mod.rs pippenger.rs precomputed_straus.rs straus.rs variable_base.rs vartime_double_base.rs

u64

constants.rs field.rs mod.rs scalar.rs

constants.rs edwards.rs field.rs lib.rs macros.rs montgomery.rs prelude.rs ristretto.rs scalar.rs traits.rs window.rs

derive_more

digest

digest.rs dyn_digest.rs errors.rs lib.rs

ed25519_dalek

constants.rs ed25519.rs errors.rs lib.rs public.rs secret.rs signature.rs

either

environmental

ethabi_decode

decoder.rs event.rs lib.rs param.rs std.rs token.rs

ethbloom

ethereum_types

hash.rs lib.rs uint.rs

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

fake_simd

fixed_hash

frame_metadata

frame_support

frame_support_procedural

construct_runtime

mod.rs parse.rs

storage

genesis_config

builder_def.rs genesis_config_def.rs mod.rs

getters.rs instance_trait.rs metadata.rs mod.rs parse.rs storage_struct.rs store_trait.rs

frame_support_procedural_tools

lib.rs syn_ext.rs

frame_support_procedural_tools_derive

frame_system

extensions

check_genesis.rs check_mortality.rs check_nonce.rs check_spec_version.rs check_tx_version.rs check_weight.rs mod.rs

lib.rs offchain.rs weights.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 thread_pool.rs unpark_mutex.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 flush.rs map_err.rs mod.rs send.rs send_all.rs with.rs with_flat_map.rs

stream

task

mod.rs spawn.rs

fns.rs lib.rs never.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

hash256_std_hasher

hash_db

hashbrown

external_trait_impls

raw

bitmask.rs mod.rs sse2.rs

lib.rs macros.rs map.rs scopeguard.rs set.rs

hex

error.rs lib.rs

hex_literal

hmac

hmac_drbg

impl_codec

impl_rlp

impl_serde

lib.rs serialize.rs

impl_trait_for_tuples

full_automatic.rs lib.rs semi_automatic.rs utils.rs

inflector

cases

camelcase

case

classcase

kebabcase

pascalcase

screamingsnakecase

sentencecase

snakecase

tablecase

titlecase

traincase

numbers

deordinalize

ordinalize

string

constants

deconstantize

demodulize

pluralize

singularize

suffix

foreignkey

integer_sqrt

itertools

keccak

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

lock_api

lib.rs mutex.rs remutex.rs rwlock.rs

log

lib.rs macros.rs

memchr

x86

avx.rs mod.rs sse2.rs

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

memory_db

memory_units

merlin

constants.rs lib.rs strobe.rs transcript.rs

nodrop

num_bigint

algorithms.rs bigint.rs biguint.rs lib.rs macros.rs monty.rs

num_cpus

lib.rs linux.rs

num_integer

lib.rs roots.rs

num_rational

num_traits

ops

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

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

object

once_cell

imp_pl.rs lib.rs

opaque_debug

pallet_bridge

pallet_verifier

parity_scale_codec

codec.rs compact.rs decode_all.rs depth_limit.rs encode_append.rs encode_like.rs joiner.rs keyedvec.rs lib.rs

parity_scale_codec_derive

decode.rs encode.rs lib.rs trait_bounds.rs utils.rs

parity_util_mem

allocators.rs lib.rs malloc_size.rs primitives_impls.rs

parity_util_mem_derive

parity_wasm

parking_lot

condvar.rs deadlock.rs elision.rs fair_mutex.rs lib.rs mutex.rs once.rs raw_fair_mutex.rs raw_mutex.rs raw_rwlock.rs remutex.rs rwlock.rs util.rs

parking_lot_core

thread_parker

linux.rs mod.rs

lib.rs parking_lot.rs spinwait.rs util.rs word_lock.rs

paste

paste_impl

enum_hack.rs lib.rs

pbkdf2

pin_project

pin_project_internal

pin_project

attribute.rs derive.rs mod.rs

lib.rs pinned_drop.rs project.rs utils.rs

pin_utils

lib.rs projection.rs stack_pin.rs

ppv_lite86

x86_64

lib.rs soft.rs types.rs

primitive_types

proc_macro2

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

proc_macro_crate

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

radium

rand

rand_chacha

chacha.rs guts.rs lib.rs

rand_core

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

rand_pcg

lib.rs pcg128.rs pcg64.rs

ref_cast

lib.rs trivial.rs

ref_cast_impl

regex

regex_syntax

rental

rental_impl

rlp

error.rs impls.rs lib.rs rlpin.rs stream.rs traits.rs

rustc_demangle

legacy.rs lib.rs v0.rs

rustc_hash

rustc_hex

schnorrkel

batch.rs cert.rs context.rs derive.rs errors.rs keys.rs lib.rs musig.rs points.rs scalars.rs serdey.rs sign.rs vrf.rs

scopeguard

secp256k1

ecmult

der.rs ecdh.rs ecdsa.rs error.rs field.rs group.rs lib.rs scalar.rs

serde

de

from_primitive.rs ignored_any.rs impls.rs mod.rs utf8.rs value.rs

private

de.rs macros.rs mod.rs ser.rs

ser

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

export.rs integer128.rs lib.rs macros.rs

serde_derive

internals

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

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

sha2

consts.rs lib.rs sha256.rs sha256_utils.rs sha512.rs sha512_utils.rs

slab

smallvec

sp_application_crypto

ecdsa.rs ed25519.rs lib.rs sr25519.rs traits.rs

sp_arithmetic

biguint.rs fixed_point.rs helpers_128bit.rs lib.rs per_things.rs rational128.rs traits.rs

sp_core

offchain

mod.rs storage.rs testing.rs

changes_trie.rs crypto.rs ecdsa.rs ed25519.rs hash.rs hasher.rs hashing.rs hexdisplay.rs lib.rs sandbox.rs sr25519.rs tasks.rs testing.rs traits.rs u32_trait.rs uint.rs vrf.rs

sp_debug_derive

impls.rs lib.rs

sp_externalities

extensions.rs lib.rs scope_limited.rs

sp_inherents

sp_io

batch_verifier.rs lib.rs

sp_panic_handler

sp_runtime

generic

block.rs checked_extrinsic.rs digest.rs era.rs header.rs mod.rs unchecked_extrinsic.rs

offchain

http.rs mod.rs storage.rs storage_lock.rs

curve.rs lib.rs random_number_generator.rs runtime_string.rs testing.rs traits.rs transaction_validity.rs

sp_runtime_interface

host.rs impls.rs lib.rs pass_by.rs util.rs wasm.rs

sp_runtime_interface_proc_macro

pass_by

codec.rs enum_.rs inner.rs mod.rs

runtime_interface

bare_function_interface.rs host_function_interface.rs mod.rs trait_decl_impl.rs

lib.rs utils.rs

sp_state_machine

sp_std

lib.rs with_std.rs

sp_storage

sp_tracing

lib.rs proxy.rs

sp_trie

error.rs lib.rs node_codec.rs node_header.rs storage_proof.rs trie_stream.rs

sp_version

sp_wasm_interface

lib.rs wasmi_impl.rs

stable_deref_trait

static_assertions

assert_cfg.rs assert_eq_align.rs assert_eq_size.rs assert_fields.rs assert_impl.rs assert_obj_safe.rs assert_trait.rs assert_type.rs const_assert.rs lib.rs

substrate_bip39

subtle

syn

synstructure

lib.rs macros.rs

thread_local

cached.rs lib.rs thread_id.rs unreachable.rs

tiny_keccak

keccak.rs lib.rs

toml

datetime.rs de.rs lib.rs macros.rs map.rs ser.rs spanned.rs tokens.rs value.rs

tracing

dispatcher.rs field.rs level_filters.rs lib.rs macros.rs span.rs stdlib.rs subscriber.rs

tracing_attributes

tracing_core

callsite.rs dispatcher.rs event.rs field.rs lib.rs metadata.rs parent.rs span.rs stdlib.rs subscriber.rs

trie_db

trie_root

twox_hash

lib.rs sixty_four.rs std_support.rs thirty_two.rs

typenum

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

uint

unicode_normalization

__test_api.rs decompose.rs lib.rs lookups.rs normalize.rs perfect_hash.rs quick_check.rs recompose.rs stream_safe.rs tables.rs

unicode_xid

lib.rs tables.rs

wasmi

memory

mmap_bytebuf.rs mod.rs

prepare

compile.rs mod.rs

func.rs global.rs host.rs imports.rs isa.rs lib.rs module.rs nan_preserving_float.rs runner.rs table.rs types.rs value.rs

wasmi_validation

context.rs func.rs lib.rs stack.rs util.rs

zeroize

zeroize_derive

//! Definition of the `Option` (optional step) combinator

use core::pin::Pin;
use futures_core::future::{Future, FusedFuture};
use futures_core::task::{Context, Poll};
use pin_project::pin_project;

/// A future representing a value which may or may not be present.
///
/// Created by the [`From`] implementation for [`Option`](std::option::Option).
///
/// # Examples
///
/// ```
/// # futures::executor::block_on(async {
/// use futures::future::OptionFuture;
///
/// let mut a: OptionFuture<_> = Some(async { 123 }).into();
/// assert_eq!(a.await, Some(123));
///
/// a = None.into();
/// assert_eq!(a.await, None);
/// # });
/// ```
#[pin_project]
#[derive(Debug, Clone)]
#[must_use = "futures do nothing unless you `.await` or poll them"]
pub struct OptionFuture<F>(#[pin] Option<F>);

impl<F: Future> Future for OptionFuture<F> {
    type Output = Option<F::Output>;

    fn poll(
        self: Pin<&mut Self>,
        cx: &mut Context<'_>,
    ) -> Poll<Self::Output> {
        match self.project().0.as_pin_mut() {
            Some(x) => x.poll(cx).map(Some),
            None => Poll::Ready(None),
        }
    }
}

impl<F: FusedFuture> FusedFuture for OptionFuture<F> {
    fn is_terminated(&self) -> bool {
        match &self.0 {
            Some(x) => x.is_terminated(),
            None => true,
        }
    }
}

impl<T> From<Option<T>> for OptionFuture<T> {
    fn from(option: Option<T>) -> Self {
        OptionFuture(option)
    }
}