preserves/implementations/rust/preserves/src/value/domain.rs

use std::io;

use super::Embeddable;
use super::IOValue;
use super::Reader;
use super::Writer;

pub trait DomainDecode<D: Embeddable> {
    fn decode_embedded<'de, 'r, R: Reader<'de>>(
        &mut self,
        r: &'r mut R,
        read_annotations: bool,
    ) -> io::Result<D>;
}

pub trait DomainEncode<D: Embeddable> {
    fn encode_embedded<W: Writer>(
        &mut self,
        w: &mut W,
        d: &D,
    ) -> io::Result<()>;
}

pub struct IOValueDomainCodec;

impl DomainDecode<IOValue> for IOValueDomainCodec {
    fn decode_embedded<'de, 'r, R: Reader<'de>>(
        &mut self,
        r: &'r mut R,
        read_annotations: bool,
    ) -> io::Result<IOValue> {
        r.demand_next(read_annotations, self)
    }
}

impl DomainEncode<IOValue> for IOValueDomainCodec {
    fn encode_embedded<W: Writer>(
        &mut self,
        w: &mut W,
        d: &IOValue,
    ) -> io::Result<()> {
        w.write(self, d)
    }
}

pub struct NoEmbeddedDomainCodec;

impl<D: Embeddable> DomainDecode<D> for NoEmbeddedDomainCodec {
    fn decode_embedded<'de, 'r, R: Reader<'de>>(
        &mut self,
        _r: &'r mut R,
        _read_annotations: bool,
    ) -> io::Result<D> {
        Err(io::Error::new(io::ErrorKind::Unsupported, "Embedded values not supported here"))
    }
}

impl<D: Embeddable> DomainEncode<D> for NoEmbeddedDomainCodec {
    fn encode_embedded<W: Writer>(
        &mut self,
        _w: &mut W,
        _d: &D,
    ) -> io::Result<()> {
        Err(io::Error::new(io::ErrorKind::Unsupported, "Embedded values not supported here"))
    }
}