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//! Entity resolver module↩
↩
use std::convert::Infallible;↩
use std::error::Error;↩
↩
use crate::events::BytesText;↩
↩
/// Used to resolve unknown entities while parsing↩
///↩
/// # Example↩
///↩
/// ```↩
/// # use serde::Deserialize;↩
/// # use pretty_assertions::assert_eq;↩
/// use regex::bytes::Regex;↩
/// use std::collections::BTreeMap;↩
/// use std::string::FromUtf8Error;↩
/// use quick_xml::de::{Deserializer, EntityResolver};↩
/// use quick_xml::events::BytesText;↩
///↩
/// struct DocTypeEntityResolver {↩
/// re: Regex,↩
/// map: BTreeMap<String, String>,↩
/// }↩
///↩
/// impl Default for DocTypeEntityResolver {↩
/// fn default() -> Self {↩
/// Self {↩
/// // We do not focus on true parsing in this example↩
/// // You should use special libraries to parse DTD↩
/// re: Regex::new(r#"<!ENTITY\s+([^ \t\r\n]+)\s+"([^"]*)"\s*>"#).unwrap(),↩
/// map: BTreeMap::new(),↩
/// }↩
/// }↩
/// }↩
///↩
/// impl EntityResolver for DocTypeEntityResolver {↩
/// type Error = FromUtf8Error;↩
///↩
/// fn capture(&mut self, doctype: BytesText) -> Result<(), Self::Error> {↩
/// for cap in self.re.captures_iter(&doctype) {↩
/// self.map.insert(↩
/// String::from_utf8(cap[1].to_vec())?,↩
/// String::from_utf8(cap[2].to_vec())?,↩
/// );↩
/// }↩
/// Ok(())↩
/// }↩
///↩
/// fn resolve(&self, entity: &str) -> Option<&str> {↩
/// self.map.get(entity).map(|s| s.as_str())↩
/// }↩
/// }↩
///↩
/// let xml_reader = br#"↩
/// <!DOCTYPE dict[ <!ENTITY e1 "entity 1"> ]>↩
/// <root>↩
/// <entity_one>&e1;</entity_one>↩
/// </root>↩
/// "#.as_ref();↩
///↩
/// let mut de = Deserializer::with_resolver(↩
/// xml_reader,↩
/// DocTypeEntityResolver::default(),↩
/// );↩
/// let data: BTreeMap<String, String> = BTreeMap::deserialize(&mut de).unwrap();↩
///↩
/// assert_eq!(data.get("entity_one"), Some(&"entity 1".to_string()));↩
/// ```↩
pub trait EntityResolver {↩
/// The error type that represents DTD parse error↩
type Error: Error;↩
↩
/// Called on contents of [`Event::DocType`] to capture declared entities.↩
/// Can be called multiple times, for each parsed `<!DOCTYPE >` declaration.↩
///↩
/// [`Event::DocType`]: crate::events::Event::DocType↩
fn capture(&mut self, doctype: BytesText) -> Result<(), Self::Error>;↩
↩
/// Called when an entity needs to be resolved.↩
///↩
/// `None` is returned if a suitable value can not be found.↩
/// In that case an [`EscapeError::UnrecognizedSymbol`] will be returned by↩
/// a deserializer.↩
///↩
/// [`EscapeError::UnrecognizedSymbol`]: crate::escape::EscapeError::UnrecognizedSymbol↩
fn resolve(&self, entity: &str) -> Option<&str>;↩
}↩
↩
/// An `EntityResolver` that does nothing and always returns `None`.↩
#[derive(Default, Copy, Clone)]↩
pub struct NoEntityResolver;↩
↩
impl EntityResolver for NoEntityResolver {↩
type Error = Infallible;↩
↩
fn capture(&mut self, _doctype: BytesText) -> Result<(), Self::Error> {↩
Ok(())↩
}↩
↩
fn resolve(&self, _entity: &str) -> Option<&str> {↩
None↩
}↩
}↩