78 строки
2.5 KiB
Rust
78 строки
2.5 KiB
Rust
// Protocol Buffers - Google's data interchange format
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// Copyright 2023 Google LLC. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file or at
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// https://developers.google.com/open-source/licenses/bsd
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//! Items specific to `optional` fields.
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#![allow(dead_code)]
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#![allow(unused)]
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use crate::__internal::Private;
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use crate::{Mut, MutProxied, MutProxy, Proxied, View, ViewProxy};
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use std::convert::{AsMut, AsRef};
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use std::fmt::{self, Debug};
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use std::panic;
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use std::ptr;
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/// A protobuf value from a field that may not be set.
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///
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/// This can be pattern matched with `match` or `if let` to determine if the
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/// field is set and access the field data.
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///
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/// Two `Optional`s are equal if they match both presence and the field values.
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#[derive(Debug, Clone, Copy, PartialEq, Eq)]
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pub enum Optional<T> {
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/// The field is set; it is present in the serialized message.
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///
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/// - For an `_opt()` accessor, this contains a `View<impl Proxied>`.
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/// - For a `_mut()` accessor, this contains a [`PresentField`] that can be
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/// used to access the current value, convert to [`Mut`], clear presence,
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/// or set a new value.
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Set(T),
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/// The field is unset; it is absent in the serialized message.
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///
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/// - For an `_opt()` accessor, this contains a `View<impl Proxied>` with
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/// the default value.
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/// - For a `_mut()` accessor, this contains an [`AbsentField`] that can be
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/// used to access the default or set a new value.
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Unset(T),
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}
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impl<T> Optional<T> {
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/// Gets the field value, ignoring whether it was set or not.
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pub fn into_inner(self) -> T {
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match self {
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Optional::Set(x) | Optional::Unset(x) => x,
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}
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}
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/// Constructs an `Optional<T>` with a `T` value and presence bit.
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pub fn new(val: T, is_set: bool) -> Self {
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if is_set { Optional::Set(val) } else { Optional::Unset(val) }
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}
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/// Converts into an `Option` of the set value, ignoring any unset value.
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pub fn into_option(self) -> Option<T> {
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if let Optional::Set(x) = self { Some(x) } else { None }
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}
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/// Returns if the field is set.
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pub fn is_set(&self) -> bool {
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matches!(self, Optional::Set(_))
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}
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/// Returns if the field is unset.
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pub fn is_unset(&self) -> bool {
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matches!(self, Optional::Unset(_))
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}
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}
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impl<T> From<Optional<T>> for Option<T> {
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fn from(x: Optional<T>) -> Option<T> {
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x.into_option()
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}
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}
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