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//! Utilities to write RDF graphs and datasets
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use super::GraphSyntax; |
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use crate::model::*; |
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use crate::DatasetSyntax; |
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use rio_api::formatter::{QuadsFormatter, TriplesFormatter}; |
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use rio_turtle::{NQuadsFormatter, NTriplesFormatter, TriGFormatter, TurtleFormatter}; |
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use rio_xml::{RdfXmlError, RdfXmlFormatter}; |
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use std::io; |
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use std::io::Write; |
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/// A serializer for RDF graph serialization formats.
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///
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/// It currently supports the following formats:
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/// * [N-Triples](https://www.w3.org/TR/n-triples/) (`GraphSyntax::NTriples`)
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/// * [Turtle](https://www.w3.org/TR/turtle/) (`GraphSyntax::Turtle`)
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/// * [RDF XML](https://www.w3.org/TR/rdf-syntax-grammar/) (`GraphSyntax::RdfXml`)
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///
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/// ```
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/// use oxigraph::io::{GraphSyntax, GraphSerializer};
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/// use oxigraph::model::*;
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///
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/// let mut buffer = Vec::new();
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/// let mut writer = GraphSerializer::from_syntax(GraphSyntax::NTriples).triple_writer(&mut buffer)?;
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/// writer.write(&Triple {
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/// subject: NamedNode::new("http://example.com/s")?.into(),
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/// predicate: NamedNode::new("http://example.com/p")?,
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/// object: NamedNode::new("http://example.com/o")?.into()
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/// })?;
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/// writer.finish()?;
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///
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///assert_eq!(buffer.as_slice(), "<http://example.com/s> <http://example.com/p> <http://example.com/o> .\n".as_bytes());
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/// # oxigraph::Result::Ok(())
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/// ```
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#[allow(missing_copy_implementations)] |
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pub struct GraphSerializer { |
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syntax: GraphSyntax, |
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} |
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impl GraphSerializer { |
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pub fn from_syntax(syntax: GraphSyntax) -> Self { |
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Self { syntax } |
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} |
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/// Returns a `TripleWriter` allowing writing triples into the given `Write` implementation
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pub fn triple_writer<W: Write>(&self, writer: W) -> Result<TripleWriter<W>, io::Error> { |
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Ok(TripleWriter { |
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formatter: match self.syntax { |
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GraphSyntax::NTriples => TripleWriterKind::NTriples(NTriplesFormatter::new(writer)), |
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GraphSyntax::Turtle => TripleWriterKind::Turtle(TurtleFormatter::new(writer)), |
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GraphSyntax::RdfXml => { |
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TripleWriterKind::RdfXml(RdfXmlFormatter::new(writer).map_err(map_xml_err)?) |
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} |
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}, |
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}) |
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} |
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} |
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/// Allows writing triples.
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/// Could be built using a `GraphSerializer`.
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///
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/// Warning: Do not forget to run the `finish` method to properly write the last bytes of the file.
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///
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/// ```
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/// use oxigraph::io::{GraphSyntax, GraphSerializer};
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/// use oxigraph::model::*;
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///
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/// let mut buffer = Vec::new();
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/// let mut writer = GraphSerializer::from_syntax(GraphSyntax::NTriples).triple_writer(&mut buffer)?;
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/// writer.write(&Triple {
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/// subject: NamedNode::new("http://example.com/s")?.into(),
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/// predicate: NamedNode::new("http://example.com/p")?,
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/// object: NamedNode::new("http://example.com/o")?.into()
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/// })?;
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/// writer.finish()?;
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///
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///assert_eq!(buffer.as_slice(), "<http://example.com/s> <http://example.com/p> <http://example.com/o> .\n".as_bytes());
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/// # oxigraph::Result::Ok(())
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/// ```
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#[must_use] |
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pub struct TripleWriter<W: Write> { |
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formatter: TripleWriterKind<W>, |
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} |
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enum TripleWriterKind<W: Write> { |
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NTriples(NTriplesFormatter<W>), |
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Turtle(TurtleFormatter<W>), |
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RdfXml(RdfXmlFormatter<W>), |
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} |
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impl<W: Write> TripleWriter<W> { |
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pub fn write(&mut self, triple: &Triple) -> Result<(), io::Error> { |
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match &mut self.formatter { |
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TripleWriterKind::NTriples(formatter) => formatter.format(&triple.into())?, |
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TripleWriterKind::Turtle(formatter) => formatter.format(&triple.into())?, |
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TripleWriterKind::RdfXml(formatter) => { |
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formatter.format(&triple.into()).map_err(map_xml_err)? |
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} |
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} |
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Ok(()) |
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} |
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/// Writes the last bytes of the file
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pub fn finish(self) -> Result<(), io::Error> { |
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match self.formatter { |
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TripleWriterKind::NTriples(formatter) => formatter.finish(), |
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TripleWriterKind::Turtle(formatter) => formatter.finish()?, |
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TripleWriterKind::RdfXml(formatter) => formatter.finish().map_err(map_xml_err)?, |
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}; |
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Ok(()) |
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} |
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} |
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/// A serializer for RDF graph serialization formats.
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///
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/// It currently supports the following formats:
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/// * [N-Quads](https://www.w3.org/TR/n-quads/) (`DatasetSyntax::NQuads`)
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/// * [TriG](https://www.w3.org/TR/trig/) (`DatasetSyntax::TriG`)
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///
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/// ```
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/// use oxigraph::io::{DatasetSyntax, DatasetSerializer};
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/// use oxigraph::model::*;
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///
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/// let mut buffer = Vec::new();
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/// let mut writer = DatasetSerializer::from_syntax(DatasetSyntax::NQuads).quad_writer(&mut buffer)?;
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/// writer.write(&Quad {
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/// subject: NamedNode::new("http://example.com/s")?.into(),
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/// predicate: NamedNode::new("http://example.com/p")?,
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/// object: NamedNode::new("http://example.com/o")?.into(),
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/// graph_name: NamedNode::new("http://example.com/g")?.into(),
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/// })?;
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/// writer.finish()?;
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///
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///assert_eq!(buffer.as_slice(), "<http://example.com/s> <http://example.com/p> <http://example.com/o> <http://example.com/g> .\n".as_bytes());
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/// # oxigraph::Result::Ok(())
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/// ```
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#[allow(missing_copy_implementations)] |
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pub struct DatasetSerializer { |
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syntax: DatasetSyntax, |
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} |
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impl DatasetSerializer { |
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pub fn from_syntax(syntax: DatasetSyntax) -> Self { |
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Self { syntax } |
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} |
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/// Returns a `QuadWriter` allowing writing triples into the given `Write` implementation
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pub fn quad_writer<W: Write>(&self, writer: W) -> Result<QuadWriter<W>, io::Error> { |
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Ok(QuadWriter { |
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formatter: match self.syntax { |
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DatasetSyntax::NQuads => QuadWriterKind::NQuads(NQuadsFormatter::new(writer)), |
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DatasetSyntax::TriG => QuadWriterKind::TriG(TriGFormatter::new(writer)), |
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}, |
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}) |
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} |
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} |
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/// Allows writing triples.
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/// Could be built using a `DatasetSerializer`.
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///
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/// Warning: Do not forget to run the `finish` method to properly write the last bytes of the file.
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///
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/// ```
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/// use oxigraph::io::{DatasetSyntax, DatasetSerializer};
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/// use oxigraph::model::*;
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///
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/// let mut buffer = Vec::new();
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/// let mut writer = DatasetSerializer::from_syntax(DatasetSyntax::NQuads).quad_writer(&mut buffer)?;
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/// writer.write(&Quad {
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/// subject: NamedNode::new("http://example.com/s")?.into(),
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/// predicate: NamedNode::new("http://example.com/p")?,
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/// object: NamedNode::new("http://example.com/o")?.into(),
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/// graph_name: NamedNode::new("http://example.com/g")?.into(),
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/// })?;
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/// writer.finish()?;
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///
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///assert_eq!(buffer.as_slice(), "<http://example.com/s> <http://example.com/p> <http://example.com/o> <http://example.com/g> .\n".as_bytes());
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/// # oxigraph::Result::Ok(())
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/// ```
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#[must_use] |
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pub struct QuadWriter<W: Write> { |
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formatter: QuadWriterKind<W>, |
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} |
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enum QuadWriterKind<W: Write> { |
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NQuads(NQuadsFormatter<W>), |
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TriG(TriGFormatter<W>), |
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} |
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impl<W: Write> QuadWriter<W> { |
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pub fn write(&mut self, triple: &Quad) -> Result<(), io::Error> { |
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match &mut self.formatter { |
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QuadWriterKind::NQuads(formatter) => formatter.format(&triple.into())?, |
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QuadWriterKind::TriG(formatter) => formatter.format(&triple.into())?, |
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} |
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Ok(()) |
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} |
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/// Writes the last bytes of the file
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pub fn finish(self) -> Result<(), io::Error> { |
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match self.formatter { |
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QuadWriterKind::NQuads(formatter) => formatter.finish(), |
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QuadWriterKind::TriG(formatter) => formatter.finish()?, |
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}; |
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Ok(()) |
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} |
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} |
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fn map_xml_err(e: RdfXmlError) -> io::Error { |
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io::Error::new(io::ErrorKind::Other, e) //TODO: drop
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} |
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