ipld_nostd/ipld/
codec.rs

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//! This module contains traits to have a unified API across codecs.
//!
//! There are two traits defined, [`Codec`] and [`Links`]. Those are separate
//! traits as the `Links` trait is not generic over a certain type.

use {
	crate::cid::Cid,
	alloc::vec::Vec,
	core2::io::{BufRead, Write},
};

/// Each IPLD codec implementation should implement this Codec trait. This way
/// codecs can be more easily exchanged or combined.
pub trait Codec<T>: Links {
	/// The multicodec code of the IPLD codec.
	const CODE: u64;
	/// The error that is returned if encoding or decoding fails.
	type Error;

	/// Decode a reader into the desired type.
	fn decode<R: BufRead>(reader: R) -> Result<T, Self::Error>;
	/// Encode a type into a writer.
	fn encode<W: Write>(writer: W, data: &T) -> Result<(), Self::Error>;

	/// Decode a slice into the desired type.
	fn decode_from_slice(bytes: &[u8]) -> Result<T, Self::Error> {
		Self::decode(bytes)
	}

	/// Encode a type into bytes.
	fn encode_to_vec(data: &T) -> Result<Vec<u8>, Self::Error> {
		let mut output = Vec::new();
		Self::encode(&mut output, data)?;
		Ok(output)
	}
}

/// Trait for returning the links of a serialized IPLD data.
pub trait Links {
	/// The error that is returned if the link extraction fails.
	type LinksError;

	/// Return all links (CIDs) that the given encoded data contains.
	fn links(bytes: &[u8])
		-> Result<impl Iterator<Item = Cid>, Self::LinksError>;
}