69 lines
2.1 KiB
Rust
69 lines
2.1 KiB
Rust
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//! # Generic iterator type implementations
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//!
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//! This module contains [`AsXml`] iterator implementations for types from
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//! foreign libraries (such as the standard library).
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//!
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//! In order to not clutter the `xso` crate's main namespace, they are
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//! stashed away in a separate module.
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// Copyright (c) 2024 Jonas Schäfer <jonas@zombofant.net>
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this
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// file, You can obtain one at http://mozilla.org/MPL/2.0/.
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use crate::error::Error;
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use crate::rxml_util::Item;
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use crate::AsXml;
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/// Helper iterator to convert an `Option<T>` to XML.
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pub struct OptionAsXml<T: Iterator>(Option<T>);
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impl<T: Iterator> OptionAsXml<T> {
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/// Construct a new iterator, wrapping the given iterator.
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///
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/// If `inner` is `None`, this iterator terminates immediately. Otherwise,
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/// it yields the elements yielded by `inner` until `inner` finishes,
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/// after which this iterator completes, too.
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pub fn new(inner: Option<T>) -> Self {
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Self(inner)
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}
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}
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impl<'x, T: Iterator<Item = Result<Item<'x>, Error>>> Iterator for OptionAsXml<T> {
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type Item = Result<Item<'x>, Error>;
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fn next(&mut self) -> Option<Self::Item> {
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self.0.as_mut()?.next()
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}
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}
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impl<T: AsXml> AsXml for Option<T> {
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type ItemIter<'x> = OptionAsXml<T::ItemIter<'x>> where T: 'x;
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fn as_xml_iter(&self) -> Result<Self::ItemIter<'_>, Error> {
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match self {
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Some(ref value) => Ok(OptionAsXml(Some(T::as_xml_iter(value)?))),
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None => Ok(OptionAsXml(None)),
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}
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}
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}
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/// Helper iterator to convert an `Box<T>` to XML.
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pub struct BoxAsXml<T: Iterator>(Box<T>);
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impl<'x, T: Iterator<Item = Result<Item<'x>, Error>>> Iterator for BoxAsXml<T> {
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type Item = Result<Item<'x>, Error>;
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fn next(&mut self) -> Option<Self::Item> {
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self.0.next()
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}
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}
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impl<T: AsXml> AsXml for Box<T> {
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type ItemIter<'x> = BoxAsXml<T::ItemIter<'x>> where T: 'x;
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fn as_xml_iter(&self) -> Result<Self::ItemIter<'_>, Error> {
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Ok(BoxAsXml(Box::new(T::as_xml_iter(&self)?)))
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}
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}
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