Tpt
5 years ago
parent
74dadf5f21
commit
4dee8a9aa2
@ -1,604 +1,22 @@ |
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//! Implementation of [RDF XML](https://www.w3.org/TR/rdf-syntax-grammar/) syntax
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use crate::model::vocab::rdf; |
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use crate::model::*; |
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use crate::model::Triple; |
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use crate::rio::rio::convert_triple; |
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use crate::Result; |
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use failure::format_err; |
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use lazy_static::lazy_static; |
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use quick_xml::events::BytesEnd; |
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use quick_xml::events::BytesStart; |
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use quick_xml::events::BytesText; |
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use quick_xml::events::Event; |
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use quick_xml::Reader; |
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use rio_api::parser::TripleParser; |
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use rio_xml::RdfXmlParser; |
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use std::collections::BTreeMap; |
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use std::io::BufRead; |
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use std::str::FromStr; |
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use url::Url; |
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/// Reads a [RDF XML](https://www.w3.org/TR/rdf-syntax-grammar/) file from a Rust `Read` and returns an iterator on the read `Triple`s
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///
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/// Warning: The `rdf:parseType="Literal"` and `rdf:parseType="Collection"` options are not supported yet
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pub fn read_rdf_xml( |
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source: impl BufRead, |
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base_uri: impl Into<Option<Url>>, |
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) -> impl Iterator<Item = Result<Triple>> { |
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let mut reader = Reader::from_reader(source); |
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reader.expand_empty_elements(true); |
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reader.trim_text(true); |
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RdfXmlIterator { |
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reader, |
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namespace_buffer: Vec::default(), |
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state: vec![RdfXmlState::Doc { |
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base_uri: base_uri.into(), |
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}], |
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object: None, |
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bnodes_map: BTreeMap::default(), |
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triples_cache: Vec::default(), |
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li_counter: Vec::default(), |
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} |
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} |
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lazy_static! { |
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static ref RDF_ABOUT: Url = |
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Url::from_str("http://www.w3.org/1999/02/22-rdf-syntax-ns#about").unwrap(); |
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static ref RDF_DATATYPE: Url = |
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Url::from_str("http://www.w3.org/1999/02/22-rdf-syntax-ns#datatype").unwrap(); |
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static ref RDF_DESCRIPTION: NamedNode = |
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NamedNode::from_str("http://www.w3.org/1999/02/22-rdf-syntax-ns#Description").unwrap(); |
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static ref RDF_ID: Url = |
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Url::from_str("http://www.w3.org/1999/02/22-rdf-syntax-ns#ID").unwrap(); |
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static ref RDF_LI: Url = |
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Url::from_str("http://www.w3.org/1999/02/22-rdf-syntax-ns#li").unwrap(); |
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static ref RDF_NODE_ID: Url = |
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Url::from_str("http://www.w3.org/1999/02/22-rdf-syntax-ns#nodeID").unwrap(); |
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static ref RDF_PARSE_TYPE: Url = |
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Url::from_str("http://www.w3.org/1999/02/22-rdf-syntax-ns#parseType").unwrap(); |
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static ref RDF_RDF: Url = |
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Url::from_str("http://www.w3.org/1999/02/22-rdf-syntax-ns#RDF").unwrap(); |
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static ref RDF_RESOURCE: Url = |
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Url::from_str("http://www.w3.org/1999/02/22-rdf-syntax-ns#resource").unwrap(); |
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} |
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struct RdfXmlIterator<R: BufRead> { |
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reader: Reader<R>, |
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namespace_buffer: Vec<u8>, |
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state: Vec<RdfXmlState>, |
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object: Option<NodeOrText>, |
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bnodes_map: BTreeMap<Vec<u8>, BlankNode>, |
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triples_cache: Vec<Triple>, |
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li_counter: Vec<usize>, |
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} |
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#[derive(Clone, Debug)] |
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enum NodeOrText { |
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Node(NamedOrBlankNode), |
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Text(String), |
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} |
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enum RdfXmlState { |
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Doc { |
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base_uri: Option<Url>, |
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}, |
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RDF { |
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base_uri: Option<Url>, |
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language: Option<LanguageTag>, |
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}, |
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NodeElt { |
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base_uri: Option<Url>, |
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language: Option<LanguageTag>, |
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subject: NamedOrBlankNode, |
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}, |
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PropertyElt { |
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//Resource, Literal or Empty property element
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uri: Url, |
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base_uri: Option<Url>, |
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language: Option<LanguageTag>, |
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subject: NamedOrBlankNode, |
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object: Option<NamedOrBlankNode>, |
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id_attr: Option<NamedNode>, |
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datatype_attr: Option<NamedNode>, |
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}, |
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ParseTypeCollectionPropertyElt { |
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uri: NamedNode, |
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base_uri: Option<Url>, |
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language: Option<LanguageTag>, |
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subject: NamedOrBlankNode, |
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id_attr: Option<NamedNode>, |
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}, |
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//TODO: ParseTypeOtherProperty and ParseTypeLiteralProperty
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} |
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impl RdfXmlState { |
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fn base_uri(&self) -> &Option<Url> { |
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match self { |
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RdfXmlState::Doc { base_uri, .. } => base_uri, |
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RdfXmlState::RDF { base_uri, .. } => base_uri, |
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RdfXmlState::NodeElt { base_uri, .. } => base_uri, |
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RdfXmlState::PropertyElt { base_uri, .. } => base_uri, |
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RdfXmlState::ParseTypeCollectionPropertyElt { base_uri, .. } => base_uri, |
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} |
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} |
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fn language(&self) -> Option<&LanguageTag> { |
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match self { |
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RdfXmlState::Doc { .. } => None, |
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RdfXmlState::RDF { language, .. } => language.as_ref(), |
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RdfXmlState::NodeElt { language, .. } => language.as_ref(), |
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RdfXmlState::PropertyElt { language, .. } => language.as_ref(), |
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RdfXmlState::ParseTypeCollectionPropertyElt { language, .. } => language.as_ref(), |
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} |
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} |
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} |
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impl<R: BufRead> Iterator for RdfXmlIterator<R> { |
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type Item = Result<Triple>; |
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fn next(&mut self) -> Option<Result<Triple>> { |
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let mut buffer = Vec::default(); |
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loop { |
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//Finish the stack
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if let Some(triple) = self.triples_cache.pop() { |
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return Some(Ok(triple)); |
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} |
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//Read more XML
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match self |
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.reader |
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.read_namespaced_event(&mut buffer, &mut self.namespace_buffer) |
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{ |
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Ok((_, event)) => match event { |
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Event::Start(event) => { |
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if let Err(error) = self.parse_start_event(&event) { |
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return Some(Err(error)); |
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} |
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} |
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Event::Text(event) => { |
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if let Err(error) = self.parse_text_event(&event) { |
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return Some(Err(error)); |
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} |
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} |
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Event::End(event) => { |
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if let Err(error) = self.parse_end_event(&event) { |
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return Some(Err(error)); |
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} |
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} |
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Event::Eof => return None, |
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_ => (), |
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}, |
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Err(error) => return Some(Err(error.into())), |
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} |
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} |
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} |
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} |
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impl<R: BufRead> RdfXmlIterator<R> { |
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fn parse_start_event(&mut self, event: &BytesStart<'_>) -> Result<()> { |
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#[derive(PartialEq, Eq)] |
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enum RdfXmlParseType { |
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Default, |
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Collection, |
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Literal, |
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Resource, |
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Other, |
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} |
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#[derive(PartialEq, Eq)] |
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enum RdfXmlNextProduction { |
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RDF, |
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NodeElt, |
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PropertyElt { subject: NamedOrBlankNode }, |
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} |
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let uri = self.resolve_tag_name(event.name())?; |
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//We read attributes
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let mut language = None; |
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let mut base_uri = None; |
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if let Some(current_state) = self.state.last() { |
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language = current_state.language().cloned(); |
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base_uri = current_state.base_uri().clone(); |
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} |
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let mut id_attr = None; |
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let mut node_id_attr = None; |
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let mut about_attr = None; |
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let mut property_attrs = Vec::default(); |
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let mut resource_attr = None; |
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let mut datatype_attr = None; |
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let mut parse_type = RdfXmlParseType::Default; |
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let mut type_attr = None; |
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for attribute in event.attributes() { |
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let attribute = attribute?; |
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match attribute.key { |
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b"xml:lang" => { |
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language = Some(LanguageTag::parse( |
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&attribute.unescape_and_decode_value(&self.reader)?, |
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)?); |
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} |
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b"xml:base" => { |
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base_uri = Some(self.resolve_uri(&attribute.unescaped_value()?, &None)?) |
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} |
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key if !key.starts_with(b"xml") => { |
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let attribute_url = self.resolve_attribute_name(key)?; |
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if attribute_url == *RDF_ID { |
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let mut id = Vec::with_capacity(attribute.value.len() + 1); |
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id.push(b'#'); |
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id.extend_from_slice(attribute.unescaped_value()?.as_ref()); |
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id_attr = Some(id); |
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} else if attribute_url == *RDF_NODE_ID { |
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node_id_attr = Some( |
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self.bnodes_map |
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.entry(attribute.unescaped_value()?.to_vec()) |
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.or_insert_with(BlankNode::default) |
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.clone(), |
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); |
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} else if attribute_url == *RDF_ABOUT { |
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about_attr = Some(attribute.unescaped_value()?.to_vec()); |
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} else if attribute_url == *RDF_RESOURCE { |
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resource_attr = Some(attribute.unescaped_value()?.to_vec()); |
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} else if attribute_url == *RDF_DATATYPE { |
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datatype_attr = Some(attribute.unescaped_value()?.to_vec()); |
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} else if attribute_url == *RDF_PARSE_TYPE { |
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parse_type = match attribute.value.as_ref() { |
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b"Collection" => RdfXmlParseType::Collection, |
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b"Literal" => RdfXmlParseType::Literal, |
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b"Resource" => RdfXmlParseType::Resource, |
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_ => RdfXmlParseType::Other, |
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}; |
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} else if attribute_url == *rdf::TYPE.as_url() { |
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type_attr = Some(attribute.unescaped_value()?.to_vec()); |
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} else { |
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property_attrs.push(( |
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NamedNode::from(attribute_url), |
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attribute.unescape_and_decode_value(&self.reader)?, |
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)); |
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} |
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} |
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_ => (), //We do not fail for unknown tags in the XML namespace
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} |
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} |
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//Parsing with the base URI
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let id_attr = match id_attr { |
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Some(uri) => Some(NamedNode::from(self.resolve_uri(&uri, &base_uri)?)), |
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None => None, |
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}; |
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let about_attr = match about_attr { |
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Some(uri) => Some(NamedNode::from(self.resolve_uri(&uri, &base_uri)?)), |
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None => None, |
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}; |
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let resource_attr = match resource_attr { |
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Some(uri) => Some(NamedNode::from(self.resolve_uri(&uri, &base_uri)?)), |
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None => None, |
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}; |
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let datatype_attr = match datatype_attr { |
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Some(uri) => Some(NamedNode::from(self.resolve_uri(&uri, &base_uri)?)), |
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None => None, |
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}; |
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let type_attr = match type_attr { |
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Some(uri) => Some(NamedNode::from(self.resolve_uri(&uri, &base_uri)?)), |
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None => None, |
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}; |
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let next_production = match self.state.last() { |
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Some(RdfXmlState::Doc { .. }) => RdfXmlNextProduction::RDF, |
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Some(RdfXmlState::RDF { .. }) => RdfXmlNextProduction::NodeElt, |
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Some(RdfXmlState::NodeElt { subject, .. }) => RdfXmlNextProduction::PropertyElt { |
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subject: subject.clone(), |
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}, |
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Some(RdfXmlState::PropertyElt { .. }) => RdfXmlNextProduction::NodeElt {}, |
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Some(RdfXmlState::ParseTypeCollectionPropertyElt { .. }) => { |
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RdfXmlNextProduction::NodeElt {} |
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} |
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None => { |
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return Err(format_err!( |
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"No state in the stack: the XML is not balanced" |
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)); |
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} |
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}; |
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let new_state = match next_production { |
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RdfXmlNextProduction::RDF => { |
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if uri == *RDF_RDF { |
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RdfXmlState::RDF { base_uri, language } |
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} else { |
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self.build_node_elt( |
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NamedNode::from(uri), |
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base_uri, |
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language, |
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id_attr, |
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node_id_attr, |
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about_attr, |
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type_attr, |
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property_attrs, |
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) |
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} |
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} |
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RdfXmlNextProduction::NodeElt => self.build_node_elt( |
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NamedNode::from(uri), |
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base_uri, |
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language, |
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id_attr, |
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node_id_attr, |
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about_attr, |
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type_attr, |
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property_attrs, |
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), |
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RdfXmlNextProduction::PropertyElt { subject } => match parse_type { |
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RdfXmlParseType::Default => { |
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if resource_attr.is_some() |
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|| node_id_attr.is_some() |
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|| !property_attrs.is_empty() |
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{ |
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let object: NamedOrBlankNode = match resource_attr { |
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Some(resource_attr) => resource_attr.into(), |
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None => match node_id_attr { |
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Some(node_id_attr) => node_id_attr.into(), |
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None => BlankNode::default().into(), |
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}, |
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}; |
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self.emit_property_attrs(&object, property_attrs, &language); |
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if let Some(type_attr) = type_attr { |
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self.triples_cache.push(Triple::new( |
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object.clone(), |
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rdf::TYPE.clone(), |
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type_attr, |
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)); |
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} |
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RdfXmlState::PropertyElt { |
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uri, |
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base_uri, |
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language, |
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subject, |
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object: Some(object), |
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id_attr, |
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datatype_attr, |
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} |
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} else { |
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RdfXmlState::PropertyElt { |
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uri, |
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base_uri, |
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language, |
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subject, |
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object: None, |
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id_attr, |
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datatype_attr, |
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} |
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} |
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} |
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RdfXmlParseType::Literal => { |
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return Err(format_err!( |
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"rdf:parseType=\"Literal\" is not supported yet" |
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)); |
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} |
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RdfXmlParseType::Resource => self.build_parse_type_resource_property_elt( |
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NamedNode::from(uri), |
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base_uri, |
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language, |
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subject, |
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id_attr, |
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), |
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RdfXmlParseType::Collection => { |
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return Err(format_err!( |
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"rdf:parseType=\"Collection\" is not supported yet" |
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)); |
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} |
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RdfXmlParseType::Other => { |
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return Err(format_err!("Arbitrary rdf:parseType are not supported yet")); |
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} |
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}, |
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}; |
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self.state.push(new_state); |
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Ok(()) |
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} |
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fn parse_end_event(&mut self, _event: &BytesEnd<'_>) -> Result<()> { |
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if let Some(current_state) = self.state.pop() { |
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self.end_state(current_state)?; |
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} |
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Ok(()) |
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} |
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fn parse_text_event(&mut self, event: &BytesText<'_>) -> Result<()> { |
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self.object = Some(NodeOrText::Text(event.unescape_and_decode(&self.reader)?)); |
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Ok(()) |
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} |
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fn resolve_tag_name(&self, qname: &[u8]) -> Result<Url> { |
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let (namespace, local_name) = self.reader.event_namespace(qname, &self.namespace_buffer); |
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self.resolve_ns_name(namespace, local_name) |
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} |
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fn resolve_attribute_name(&self, qname: &[u8]) -> Result<Url> { |
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let (namespace, local_name) = self |
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.reader |
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.attribute_namespace(qname, &self.namespace_buffer); |
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self.resolve_ns_name(namespace, local_name) |
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} |
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fn resolve_ns_name(&self, namespace: Option<&[u8]>, local_name: &[u8]) -> Result<Url> { |
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Ok(Url::parse( |
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&(match namespace { |
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Some(namespace) => self.reader.decode(namespace) + self.reader.decode(local_name), |
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None => self.reader.decode(local_name), |
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}), |
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)?) |
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} |
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fn resolve_uri(&self, uri: &[u8], base: &Option<Url>) -> Result<Url> { |
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Ok(Url::options() |
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.base_url(base.as_ref()) |
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.parse(&self.reader.decode(uri))?) |
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} |
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fn build_node_elt( |
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&mut self, |
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uri: NamedNode, |
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base_uri: Option<Url>, |
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language: Option<LanguageTag>, |
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id_attr: Option<NamedNode>, |
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node_id_attr: Option<BlankNode>, |
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about_attr: Option<NamedNode>, |
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type_attr: Option<NamedNode>, |
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property_attrs: Vec<(NamedNode, String)>, |
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) -> RdfXmlState { |
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self.object = None; //We reset object return: we are in a list of elements
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let subject = match id_attr { |
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Some(id_attr) => id_attr.into(), |
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None => match about_attr { |
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Some(about_attr) => about_attr.into(), |
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None => node_id_attr.unwrap_or_else(BlankNode::default).into(), |
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}, |
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}; |
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self.emit_property_attrs(&subject, property_attrs, &language); |
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if let Some(type_attr) = type_attr { |
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self.triples_cache |
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.push(Triple::new(subject.clone(), rdf::TYPE.clone(), type_attr)); |
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} |
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if uri != *RDF_DESCRIPTION { |
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self.triples_cache |
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.push(Triple::new(subject.clone(), rdf::TYPE.clone(), uri)); |
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} |
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self.li_counter.push(0); |
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RdfXmlState::NodeElt { |
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base_uri, |
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language, |
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subject: subject.clone(), |
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} |
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} |
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fn build_parse_type_resource_property_elt( |
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&mut self, |
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uri: NamedNode, |
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base_uri: Option<Url>, |
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language: Option<LanguageTag>, |
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subject: NamedOrBlankNode, |
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id_attr: Option<NamedNode>, |
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) -> RdfXmlState { |
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let object = BlankNode::default(); |
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let triple = Triple::new(subject, uri, object.clone()); |
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if let Some(id_attr) = id_attr { |
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self.reify(&triple, id_attr.into()); |
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} |
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self.triples_cache.push(triple); |
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self.li_counter.push(0); |
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RdfXmlState::NodeElt { |
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base_uri, |
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language, |
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subject: object.into(), |
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} |
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} |
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fn end_state(&mut self, state: RdfXmlState) -> Result<()> { |
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match state { |
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RdfXmlState::PropertyElt { |
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uri, |
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language, |
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subject, |
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id_attr, |
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datatype_attr, |
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object, |
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.. |
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} => { |
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let predicate = if uri == *RDF_LI { |
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if let Some(li_counter) = self.li_counter.last_mut() { |
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*li_counter += 1; |
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NamedNode::from_str(&format!( |
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"http://www.w3.org/1999/02/22-rdf-syntax-ns#_{}", |
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li_counter |
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))? |
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} else { |
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NamedNode::from(uri) |
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} |
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} else { |
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NamedNode::from(uri) |
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}; |
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let object: Term = match object { |
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Some(object) => object.into(), |
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None => match self.object.clone() { |
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Some(NodeOrText::Node(node)) => node.into(), |
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Some(NodeOrText::Text(text)) => { |
||||
self.new_literal(text, language, datatype_attr).into() |
||||
} |
||||
None => self |
||||
.new_literal(String::default(), language, datatype_attr) |
||||
.into(), |
||||
}, |
||||
}; |
||||
self.object = None; //We have used self.object
|
||||
let triple = Triple::new(subject, predicate, object); |
||||
if let Some(id_attr) = id_attr { |
||||
self.reify(&triple, id_attr.into()); |
||||
} |
||||
self.triples_cache.push(triple); |
||||
} |
||||
RdfXmlState::NodeElt { subject, .. } => { |
||||
self.object = Some(NodeOrText::Node(subject)); |
||||
self.li_counter.pop(); |
||||
} |
||||
_ => (), |
||||
} |
||||
Ok(()) |
||||
} |
||||
|
||||
fn new_literal( |
||||
&self, |
||||
text: String, |
||||
language: Option<LanguageTag>, |
||||
datatype: Option<NamedNode>, |
||||
) -> Literal { |
||||
if let Some(datatype) = datatype { |
||||
Literal::new_typed_literal(text, datatype) |
||||
} else if let Some(language) = language { |
||||
Literal::new_language_tagged_literal(text, language) |
||||
} else { |
||||
Literal::new_simple_literal(text) |
||||
} |
||||
} |
||||
|
||||
fn reify(&mut self, triple: &Triple, statement_id: NamedOrBlankNode) { |
||||
self.triples_cache.push(Triple::new( |
||||
statement_id.clone(), |
||||
rdf::OBJECT.clone(), |
||||
triple.object().clone(), |
||||
)); |
||||
self.triples_cache.push(Triple::new( |
||||
statement_id.clone(), |
||||
rdf::PREDICATE.clone(), |
||||
triple.predicate().clone(), |
||||
)); |
||||
self.triples_cache.push(Triple::new( |
||||
statement_id.clone(), |
||||
rdf::SUBJECT.clone(), |
||||
triple.subject().clone(), |
||||
)); |
||||
self.triples_cache.push(Triple::new( |
||||
statement_id, |
||||
rdf::TYPE.clone(), |
||||
rdf::STATEMENT.clone(), |
||||
)); |
||||
} |
||||
|
||||
fn emit_property_attrs( |
||||
&mut self, |
||||
subject: &NamedOrBlankNode, |
||||
literal_attributes: Vec<(NamedNode, String)>, |
||||
language: &Option<LanguageTag>, |
||||
) { |
||||
for (literal_predicate, literal_value) in literal_attributes { |
||||
self.triples_cache.push(Triple::new( |
||||
subject.clone(), |
||||
literal_predicate, |
||||
if let Some(language) = language { |
||||
Literal::new_language_tagged_literal(literal_value, language.clone()) |
||||
} else { |
||||
Literal::new_simple_literal(literal_value) |
||||
}, |
||||
)); |
||||
} |
||||
} |
||||
/// Reads a [RDF XML](https://www.w3.org/TR/rdf-syntax-grammar/) file from a Rust `BufRead` and returns an iterator of the read `Triple`s
|
||||
pub fn read_rdf_xml<R: BufRead>( |
||||
reader: R, |
||||
base_url: Option<Url>, |
||||
) -> Result<impl Iterator<Item = Result<Triple>>> { |
||||
let mut bnode_map = BTreeMap::default(); |
||||
Ok( |
||||
RdfXmlParser::new(reader, base_url.as_ref().map_or("", |url| url.as_str()))? |
||||
.into_iter(move |t| convert_triple(t, &mut bnode_map)), |
||||
) |
||||
} |
||||
|
||||
Loading…
Reference in new issue