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//! This module provides an object safe equivalent of the `tendermint_proto::Protobuf` trait,
//! thereby allowing for easy Google Protocol Buffers encoding and decoding of domain types with
//! validation.
//!
//! Domain types implementing the `Protobuf` trait are expected to implement `TryFrom<T>` and
//! `Into<T>` where `T` is the raw type. The equivalent object safe `erased` counterparts have
//! blanket implementations and are derived automatically.
//!
//! ## Examples
//!
//! ```rust
//! use core::convert::TryFrom;
//!
//! use prost::Message;
//! use ibc_proto::protobuf::Protobuf;
//!
//! // This struct would ordinarily be automatically generated by prost.
//! #[derive(Clone, PartialEq, Message)]
//! pub struct MyRawType {
//! #[prost(uint64, tag="1")]
//! pub a: u64,
//! #[prost(string, tag="2")]
//! pub b: String,
//! }
//!
//! #[derive(Clone)]
//! pub struct MyDomainType {
//! a: u64,
//! b: String,
//! }
//!
//! impl MyDomainType {
//! // Trivial constructor with basic validation logic.
//! pub fn new(a: u64, b: String) -> Result<Self, String> {
//! if a < 1 {
//! return Err("a must be greater than 0".to_owned());
//! }
//! Ok(Self { a, b })
//! }
//! }
//!
//! impl TryFrom<MyRawType> for MyDomainType {
//! type Error = String;
//!
//! fn try_from(value: MyRawType) -> Result<Self, Self::Error> {
//! Self::new(value.a, value.b)
//! }
//! }
//!
//! impl From<MyDomainType> for MyRawType {
//! fn from(value: MyDomainType) -> Self {
//! Self { a: value.a, b: value.b }
//! }
//! }
//!
//! impl Protobuf<MyRawType> for MyDomainType {}
//! ```
mod erased;
mod error;
#[allow(unused_imports)]
use alloc::boxed::Box;
use alloc::string::String;
use alloc::vec::Vec;
use core::fmt::Display;
use bytes::Buf;
use prost::Message;
use subtle_encoding::hex;
pub use self::error::Error;
/// Object safe equivalent of `tendermint_proto::Protobuf`.
pub trait Protobuf<Raw: Message + Default>
where
Self: erased::TryFrom<Raw> + erased::CloneInto<Raw>,
<Self as erased::TryFrom<Raw>>::Error: Display,
{
/// Encode into a buffer in Protobuf format.
///
/// Uses [`prost::Message::encode`] after converting into its counterpart
/// Protobuf data structure.
///
/// [`prost::Message::encode`]: https://docs.rs/prost/*/prost/trait.Message.html#method.encode
fn encode(&self, buf: &mut Vec<u8>) -> Result<(), Error> {
self.clone_into().encode(buf).map_err(Error::encode_message)
}
/// Encode with a length-delimiter to a buffer in Protobuf format.
///
/// An error will be returned if the buffer does not have sufficient capacity.
///
/// Uses [`prost::Message::encode_length_delimited`] after converting into
/// its counterpart Protobuf data structure.
///
/// [`prost::Message::encode_length_delimited`]: https://docs.rs/prost/*/prost/trait.Message.html#method.encode_length_delimited
fn encode_length_delimited(&self, buf: &mut Vec<u8>) -> Result<(), Error> {
self.clone_into()
.encode_length_delimited(buf)
.map_err(Error::encode_message)
}
/// Constructor that attempts to decode an instance from a buffer.
///
/// The entire buffer will be consumed.
///
/// Similar to [`prost::Message::decode`] but with additional validation
/// prior to constructing the destination type.
///
/// [`prost::Message::decode`]: https://docs.rs/prost/*/prost/trait.Message.html#method.decode
fn decode<B: Buf>(buf: B) -> Result<Self, Error>
where
Self: Sized,
{
let raw = Raw::decode(buf).map_err(Error::decode_message)?;
Self::try_from(raw).map_err(Error::try_from::<Raw, Self, _>)
}
/// Constructor that attempts to decode a length-delimited instance from
/// the buffer.
///
/// The entire buffer will be consumed.
///
/// Similar to [`prost::Message::decode_length_delimited`] but with
/// additional validation prior to constructing the destination type.
///
/// [`prost::Message::decode_length_delimited`]: https://docs.rs/prost/*/prost/trait.Message.html#method.decode_length_delimited
fn decode_length_delimited<B: Buf>(buf: B) -> Result<Self, Error>
where
Self: Sized,
{
let raw = Raw::decode_length_delimited(buf).map_err(Error::decode_message)?;
Self::try_from(raw).map_err(Error::try_from::<Raw, Self, _>)
}
/// Returns the encoded length of the message without a length delimiter.
///
/// Uses [`prost::Message::encoded_len`] after converting to its
/// counterpart Protobuf data structure.
///
/// [`prost::Message::encoded_len`]: https://docs.rs/prost/*/prost/trait.Message.html#method.encoded_len
fn encoded_len(&self) -> usize {
self.clone_into().encoded_len()
}
/// Encodes into a Protobuf-encoded `Vec<u8>`.
fn encode_vec(&self) -> Vec<u8> {
self.clone_into().encode_to_vec()
}
/// Constructor that attempts to decode a Protobuf-encoded instance from a
/// `Vec<u8>` (or equivalent).
fn decode_vec(v: &[u8]) -> Result<Self, Error>
where
Self: Sized,
{
Self::decode(v)
}
/// Encode with a length-delimiter to a `Vec<u8>` Protobuf-encoded message.
fn encode_length_delimited_vec(&self) -> Vec<u8> {
self.clone_into().encode_length_delimited_to_vec()
}
/// Constructor that attempts to decode a Protobuf-encoded instance with a
/// length-delimiter from a `Vec<u8>` or equivalent.
fn decode_length_delimited_vec(v: &[u8]) -> Result<Self, Error>
where
Self: Sized,
{
Self::decode_length_delimited(v)
}
fn encode_to_hex_string(&self) -> String {
let buf = self.encode_vec();
let encoded = hex::encode(buf);
String::from_utf8(encoded).expect("hex-encoded string should always be valid UTF-8")
}
}
#[cfg(test)]
mod test {
use core::convert::{From, TryFrom};
use super::*;
use crate::google::protobuf::Any;
#[test]
fn test_protobuf_object_safety() {
let _test: Option<Box<dyn Protobuf<Any, Error = Error>>> = None;
}
#[test]
fn test_protobuf_blanket_impls() {
trait Foo: Protobuf<Any, Error = Error> {}
#[derive(Clone)]
struct Domain;
impl Foo for Domain {}
impl Protobuf<Any> for Domain {}
impl TryFrom<Any> for Domain {
type Error = Error;
fn try_from(_: Any) -> Result<Self, Self::Error> {
unimplemented!()
}
}
impl From<Domain> for Any {
fn from(_: Domain) -> Self {
unimplemented!()
}
}
}
}