245 lines
7.6 KiB
Rust
245 lines
7.6 KiB
Rust
use tokio::io::{AsyncWrite, AsyncBufRead};
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use quick_xml::events::{Event, BytesEnd, BytesStart, BytesText};
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use quick_xml::name::{Namespace, QName, PrefixDeclaration, ResolveResult, ResolveResult::*};
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use quick_xml::reader::NsReader;
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use super::error::ParsingError;
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// Constants
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pub const DAV_URN: &[u8] = b"DAV:";
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pub const CAL_URN: &[u8] = b"urn:ietf:params:xml:ns:caldav";
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pub const CARD_URN: &[u8] = b"urn:ietf:params:xml:ns:carddav";
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// Async traits
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pub trait IWrite = AsyncWrite + Unpin;
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pub trait IRead = AsyncBufRead + Unpin + 'static;
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// Serialization/Deserialization traits
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pub trait QWrite {
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async fn qwrite(&self, xml: &mut Writer<impl IWrite>) -> Result<(), quick_xml::Error>;
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}
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pub trait QRead<T> {
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async fn qread(xml: &mut Reader<impl IRead>) -> Result<T, ParsingError>;
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}
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// The representation of an XML node in Rust
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pub trait Node<T> = QRead<T> + QWrite + std::fmt::Debug + PartialEq;
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// ---------------
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/// Transform a Rust object into an XML stream of characters
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pub struct Writer<T: IWrite> {
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pub q: quick_xml::writer::Writer<T>,
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pub ns_to_apply: Vec<(String, String)>,
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}
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impl<T: IWrite> Writer<T> {
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pub fn create_dav_element(&mut self, name: &str) -> BytesStart<'static> {
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self.create_ns_element("D", name)
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}
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pub fn create_cal_element(&mut self, name: &str) -> BytesStart<'static> {
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self.create_ns_element("C", name)
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}
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fn create_ns_element(&mut self, ns: &str, name: &str) -> BytesStart<'static> {
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let mut start = BytesStart::new(format!("{}:{}", ns, name));
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if !self.ns_to_apply.is_empty() {
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start.extend_attributes(self.ns_to_apply.iter().map(|(k, n)| (k.as_str(), n.as_str())));
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self.ns_to_apply.clear()
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}
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start
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}
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}
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/// Transform an XML stream of characters into a Rust object
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pub struct Reader<T: IRead> {
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pub rdr: NsReader<T>,
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evt: Event<'static>,
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buf: Vec<u8>,
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}
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impl<T: IRead> Reader<T> {
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pub async fn new(mut rdr: NsReader<T>) -> Result<Self, ParsingError> {
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let mut buf: Vec<u8> = vec![];
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let evt = rdr.read_event_into_async(&mut buf).await?.into_owned();
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buf.clear();
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Ok(Self { evt, rdr, buf })
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}
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pub fn peek(&self) -> &Event<'static> {
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&self.evt
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}
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/// skip tag. Can't skip end, can't skip eof.
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pub async fn skip(&mut self) -> Result<Event<'static>, ParsingError> {
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println!("skip on {:?}", &self.evt);
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match &self.evt {
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Event::Start(b) => {
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let _span = self.rdr.read_to_end_into_async(b.to_end().name(), &mut self.buf).await?;
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self.next().await
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},
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Event::End(_) => Err(ParsingError::WrongToken),
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Event::Eof => Err(ParsingError::Eof),
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_ => self.next().await,
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}
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}
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/// read one more tag
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pub async fn next(&mut self) -> Result<Event<'static>, ParsingError> {
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let evt = self.rdr.read_event_into_async(&mut self.buf).await?.into_owned();
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self.buf.clear();
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let old_evt = std::mem::replace(&mut self.evt, evt);
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Ok(old_evt)
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}
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/// check if this is the desired tag
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pub fn is_tag(&self, ns: &[u8], key: &str) -> bool {
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let qname = match self.peek() {
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Event::Start(bs) | Event::Empty(bs) => bs.name(),
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Event::End(be) => be.name(),
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_ => return false,
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};
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let (extr_ns, local) = self.rdr.resolve_element(qname);
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if local.into_inner() != key.as_bytes() {
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return false
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}
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match extr_ns {
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ResolveResult::Bound(v) => v.into_inner() == ns,
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_ => false,
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}
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}
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/*
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* Disabled
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/// maybe find start tag
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pub async fn maybe_tag_start(&mut self, ns: &[u8], key: &str) -> Result<Option<Event<'static>>, ParsingError> {
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println!("maybe start tag {}", key);
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let peek = self.peek();
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match peek {
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Event::Start(_) | Event::Empty(_) if self.is_tag(ns, key) => Ok(Some(self.next().await?)),
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_ => Ok(None),
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}
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}
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/// find start tag
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pub async fn tag_start(&mut self, ns: &[u8], key: &str) -> Result<Event<'static>, ParsingError> {
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loop {
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match self.peek() {
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Event::Start(b) if self.is_tag(ns, key) => break,
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_ => { self.skip().await?; },
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}
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}
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self.next().await
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}
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*/
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// find stop tag
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pub async fn tag_stop(&mut self, ns: &[u8], key: &str) -> Result<Event<'static>, ParsingError> {
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println!("search stop tag {}", key);
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loop {
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match self.peek() {
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Event::End(b) if self.is_tag(ns, key) => break,
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_ => { self.skip().await?; },
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}
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}
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self.next().await
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}
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pub async fn tag_string(&mut self) -> Result<String, ParsingError> {
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let mut acc = String::new();
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loop {
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match self.peek() {
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Event::CData(unescaped) => {
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acc.push_str(std::str::from_utf8(unescaped.as_ref())?);
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self.next().await?
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},
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Event::Text(escaped) => {
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acc.push_str(escaped.unescape()?.as_ref());
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self.next().await?
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}
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Event::End(_) | Event::Start(_) | Event::Empty(_) => return Ok(acc),
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_ => self.next().await?,
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};
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}
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}
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// NEW API
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pub async fn maybe_read<N: Node<N>>(&mut self, t: &mut Option<N>, dirty: &mut bool) -> Result<(), ParsingError> {
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match N::qread(self).await {
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Ok(v) => {
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*t = Some(v);
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*dirty = true;
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Ok(())
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},
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Err(ParsingError::Recoverable) => Ok(()),
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Err(e) => Err(e),
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}
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}
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pub async fn maybe_push<N: Node<N>>(&mut self, t: &mut Vec<N>, dirty: &mut bool) -> Result<(), ParsingError> {
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match N::qread(self).await {
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Ok(v) => {
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t.push(v);
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*dirty = true;
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Ok(())
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},
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Err(ParsingError::Recoverable) => Ok(()),
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Err(e) => Err(e),
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}
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}
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pub async fn find<N: Node<N>>(&mut self) -> Result<N, ParsingError> {
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loop {
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// Try parse
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match N::qread(self).await {
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Err(ParsingError::Recoverable) => (),
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otherwise => return otherwise,
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}
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// If recovered, skip the element
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self.skip().await?;
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}
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}
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pub async fn maybe_find<N: Node<N>>(&mut self) -> Result<Option<N>, ParsingError> {
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loop {
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// Try parse
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match N::qread(self).await {
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Err(ParsingError::Recoverable) => (),
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otherwise => return otherwise.map(Some),
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}
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match self.peek() {
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Event::End(_) => return Ok(None),
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_ => self.skip().await?,
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};
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}
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}
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pub async fn collect<N: Node<N>>(&mut self) -> Result<Vec<N>, ParsingError> {
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let mut acc = Vec::new();
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loop {
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match N::qread(self).await {
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Err(ParsingError::Recoverable) => match self.peek() {
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Event::End(_) => return Ok(acc),
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_ => {
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self.skip().await?;
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},
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},
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Ok(v) => acc.push(v),
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Err(e) => return Err(e),
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}
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}
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}
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pub async fn open(&mut self, ns: &[u8], key: &str) -> Result<Event<'static>, ParsingError> {
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if self.is_tag(ns, key) {
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return self.next().await
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}
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return Err(ParsingError::Recoverable);
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}
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}
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