"1" .')
/// >>> list(parse(input, "text/turtle", base_iri="http://example.com/"))
/// [ predicate= object=>>]
#[pyfunction]
#[pyo3(text_signature = "(input, mime_type, *, base_iri = None)")]
pub fn parse(
input: PyObject,
mime_type: &str,
base_iri: Option<&str>,
py: Python<'_>,
) -> PyResult {
let input = if let Ok(path) = input.extract::<&str>(py) {
PyReadable::from_file(path, py)
} else {
PyReadable::from_data(input, py)
}
.map_err(map_io_err)?;
if let Some(graph_format) = GraphFormat::from_media_type(mime_type) {
let mut parser = GraphParser::from_format(graph_format);
if let Some(base_iri) = base_iri {
parser = parser
.with_base_iri(base_iri)
.map_err(|e| PyValueError::new_err(e.to_string()))?;
}
Ok(PyTripleReader {
inner: py.allow_threads(|| parser.read_triples(input).map_err(map_parse_error))?,
}
.into_py(py))
} else if let Some(dataset_format) = DatasetFormat::from_media_type(mime_type) {
let mut parser = DatasetParser::from_format(dataset_format);
if let Some(base_iri) = base_iri {
parser = parser
.with_base_iri(base_iri)
.map_err(|e| PyValueError::new_err(e.to_string()))?;
}
Ok(PyQuadReader {
inner: py.allow_threads(|| parser.read_quads(input).map_err(map_parse_error))?,
}
.into_py(py))
} else {
Err(PyValueError::new_err(format!(
"Not supported MIME type: {mime_type}"
)))
}
}
/// Serializes an RDF graph or dataset.
///
/// It currently supports the following formats:
///
/// * `N-Triples `_ (``application/n-triples``)
/// * `N-Quads `_ (``application/n-quads``)
/// * `Turtle `_ (``text/turtle``)
/// * `TriG `_ (``application/trig``)
/// * `RDF/XML `_ (``application/rdf+xml``)
///
/// It supports also some MIME type aliases.
/// For example, ``application/turtle`` could also be used for `Turtle `_
/// and ``application/xml`` for `RDF/XML `_.
///
/// :param input: the RDF triples and quads to serialize.
/// :type input: iterable(Triple) or iterable(Quad)
/// :param output: The binary I/O object or file path to write to. For example, it could be a file path as a string or a file writer opened in binary mode with ``open('my_file.ttl', 'wb')``.
/// :type output: io.RawIOBase or io.BufferedIOBase or str
/// :param mime_type: the MIME type of the RDF serialization.
/// :type mime_type: str
/// :rtype: None
/// :raises ValueError: if the MIME type is not supported.
/// :raises TypeError: if a triple is given during a quad format serialization or reverse.
///
/// >>> output = io.BytesIO()
/// >>> serialize([Triple(NamedNode('http://example.com'), NamedNode('http://example.com/p'), Literal('1'))], output, "text/turtle")
/// >>> output.getvalue()
/// b' "1" .\n'
#[pyfunction]
#[pyo3(text_signature = "(input, output, mime_type)")]
pub fn serialize(input: &PyAny, output: PyObject, mime_type: &str, py: Python<'_>) -> PyResult<()> {
let output = if let Ok(path) = output.extract::<&str>(py) {
PyWritable::from_file(path, py)
} else {
PyWritable::from_data(output)
}
.map_err(map_io_err)?;
if let Some(graph_format) = GraphFormat::from_media_type(mime_type) {
let mut writer = GraphSerializer::from_format(graph_format)
.triple_writer(output)
.map_err(map_io_err)?;
for i in input.iter()? {
writer
.write(&*i?.downcast::>()?.borrow())
.map_err(map_io_err)?;
}
writer.finish().map_err(map_io_err)?;
Ok(())
} else if let Some(dataset_format) = DatasetFormat::from_media_type(mime_type) {
let mut writer = DatasetSerializer::from_format(dataset_format)
.quad_writer(output)
.map_err(map_io_err)?;
for i in input.iter()? {
writer
.write(&*i?.downcast::>()?.borrow())
.map_err(map_io_err)?;
}
writer.finish().map_err(map_io_err)?;
Ok(())
} else {
Err(PyValueError::new_err(format!(
"Not supported MIME type: {mime_type}"
)))
}
}
#[pyclass(name = "TripleReader")]
pub struct PyTripleReader {
inner: TripleReader,
}
#[pymethods]
impl PyTripleReader {
fn __iter__(slf: PyRef<'_, Self>) -> Py {
slf.into()
}
fn __next__(&mut self, py: Python<'_>) -> PyResult> {
py.allow_threads(|| {
self.inner
.next()
.map(|q| Ok(q.map_err(map_parse_error)?.into()))
.transpose()
})
}
}
#[pyclass(name = "QuadReader")]
pub struct PyQuadReader {
inner: QuadReader,
}
#[pymethods]
impl PyQuadReader {
fn __iter__(slf: PyRef<'_, Self>) -> Py {
slf.into()
}
fn __next__(&mut self, py: Python<'_>) -> PyResult> {
py.allow_threads(|| {
self.inner
.next()
.map(|q| Ok(q.map_err(map_parse_error)?.into()))
.transpose()
})
}
}
pub(crate) enum PyReadable {
Bytes(Cursor>),
Io(BufReader),
File(BufReader),
}
impl PyReadable {
pub fn from_file(file: &str, py: Python<'_>) -> io::Result {
Ok(Self::File(BufReader::new(
py.allow_threads(|| File::open(file))?,
)))
}
pub fn from_data(data: PyObject, py: Python<'_>) -> io::Result {
Ok(if let Ok(bytes) = data.extract::>(py) {
Self::Bytes(Cursor::new(bytes))
} else if let Ok(string) = data.extract::(py) {
Self::Bytes(Cursor::new(string.into_bytes()))
} else {
Self::Io(BufReader::new(PyIo(data)))
})
}
}
impl Read for PyReadable {
fn read(&mut self, buf: &mut [u8]) -> io::Result {
match self {
Self::Bytes(bytes) => bytes.read(buf),
Self::Io(io) => io.read(buf),
Self::File(file) => file.read(buf),
}
}
}
impl BufRead for PyReadable {
fn fill_buf(&mut self) -> io::Result<&[u8]> {
match self {
Self::Bytes(bytes) => bytes.fill_buf(),
Self::Io(io) => io.fill_buf(),
Self::File(file) => file.fill_buf(),
}
}
fn consume(&mut self, amt: usize) {
match self {
Self::Bytes(bytes) => bytes.consume(amt),
Self::Io(io) => io.consume(amt),
Self::File(file) => file.consume(amt),
}
}
}
pub(crate) enum PyWritable {
Io(BufWriter),
File(BufWriter),
}
impl PyWritable {
pub fn from_file(file: &str, py: Python<'_>) -> io::Result {
Ok(Self::File(BufWriter::new(
py.allow_threads(|| File::create(file))?,
)))
}
pub fn from_data(data: PyObject) -> io::Result {
Ok(Self::Io(BufWriter::new(PyIo(data))))
}
}
impl Write for PyWritable {
fn write(&mut self, buf: &[u8]) -> io::Result {
match self {
Self::Io(io) => io.write(buf),
Self::File(file) => file.write(buf),
}
}
fn flush(&mut self) -> io::Result<()> {
match self {
Self::Io(io) => io.flush(),
Self::File(file) => file.flush(),
}
}
}
pub(crate) struct PyIo(PyObject);
impl Read for PyIo {
fn read(&mut self, mut buf: &mut [u8]) -> io::Result {
Python::with_gil(|py| {
let read = self
.0
.call_method(py, "read", (buf.len(),), None)
.map_err(to_io_err)?;
let bytes = read
.extract::<&[u8]>(py)
.or_else(|e| {
read.extract::<&str>(py)
.map(|s| s.as_bytes())
.map_err(|_| e)
})
.map_err(to_io_err)?;
buf.write_all(bytes)?;
Ok(bytes.len())
})
}
}
impl Write for PyIo {
fn write(&mut self, buf: &[u8]) -> io::Result {
Python::with_gil(|py| {
self.0
.call_method(py, "write", (PyBytes::new(py, buf),), None)
.map_err(to_io_err)?
.extract::(py)
.map_err(to_io_err)
})
}
fn flush(&mut self) -> io::Result<()> {
Python::with_gil(|py| {
self.0.call_method(py, "flush", (), None)?;
Ok(())
})
}
}
fn to_io_err(error: impl Into) -> io::Error {
io::Error::new(io::ErrorKind::Other, error.into())
}
pub(crate) fn map_io_err(error: io::Error) -> PyErr {
if error.get_ref().map_or(false, |s| s.is::()) {
*error.into_inner().unwrap().downcast().unwrap()
} else {
PyIOError::new_err(error.to_string())
}
}
pub(crate) fn map_parse_error(error: ParseError) -> PyErr {
match error {
ParseError::Syntax(error) => PySyntaxError::new_err(error.to_string()),
ParseError::Io(error) => map_io_err(error),
}
}
/// Release the GIL
/// There should not be ANY use of pyo3 code inside of this method!!!
///
/// Code from pyo3: https://github.com/PyO3/pyo3/blob/a67180c8a42a0bc0fdc45b651b62c0644130cf47/src/python.rs#L366
#[allow(unsafe_code)]
pub(crate) fn allow_threads_unsafe(f: impl FnOnce() -> T) -> T {
struct RestoreGuard {
tstate: *mut pyo3::ffi::PyThreadState,
}
impl Drop for RestoreGuard {
fn drop(&mut self) {
unsafe {
pyo3::ffi::PyEval_RestoreThread(self.tstate);
}
}
}
let _guard = RestoreGuard {
tstate: unsafe { pyo3::ffi::PyEval_SaveThread() },
};
f()
}