From 8f2fc9e540d8772f015aa8008bd752b2cf80fda3 Mon Sep 17 00:00:00 2001 From: "sinu.eth" <65924192+sinui0@users.noreply.github.com> Date: Mon, 4 Mar 2024 12:44:56 -0800 Subject: [PATCH] feat: serio (#24) * feat: serio * add IoStreamExt * fix doc link * add into_stream * pin project IntoSink * add flush method to SinkExt * add duplex traits * Apply suggestions from code review Co-authored-by: dan * add Framed test --------- Co-authored-by: dan --- Cargo.toml | 10 +- serio/Cargo.toml | 33 +++ serio/LICENSE-APACHE | 203 ++++++++++++++++++ serio/LICENSE-MIT | 27 +++ serio/README.md | 11 + serio/examples/tokio_codec.rs | 47 +++++ serio/src/channel.rs | 192 +++++++++++++++++ serio/src/codec.rs | 172 +++++++++++++++ serio/src/future.rs | 10 + serio/src/lib.rs | 36 ++++ serio/src/sink.rs | 387 ++++++++++++++++++++++++++++++++++ serio/src/stream.rs | 331 +++++++++++++++++++++++++++++ 12 files changed, 1458 insertions(+), 1 deletion(-) create mode 100644 serio/Cargo.toml create mode 100644 serio/LICENSE-APACHE create mode 100644 serio/LICENSE-MIT create mode 100644 serio/README.md create mode 100644 serio/examples/tokio_codec.rs create mode 100644 serio/src/channel.rs create mode 100644 serio/src/codec.rs create mode 100644 serio/src/future.rs create mode 100644 serio/src/lib.rs create mode 100644 serio/src/sink.rs create mode 100644 serio/src/stream.rs diff --git a/Cargo.toml b/Cargo.toml index 67e691e..10473b9 100644 --- a/Cargo.toml +++ b/Cargo.toml @@ -1,18 +1,23 @@ [workspace] -members = ["utils", "utils-aio", "spansy"] +members = ["utils", "utils-aio", "spansy", "serio"] [workspace.dependencies] tlsn-utils = { path = "utils" } tlsn-utils-aio = { path = "utils-aio" } spansy = { path = "spansy" } +serio = { path = "serio" } rand = "0.8" thiserror = "1" async-trait = "0.1" prost = "0.9" futures = "0.3" +futures-sink = "0.3" +futures-core = "0.3" +futures-channel = "0.3" futures-util = "0.3" tokio-util = "0.7" +tokio-serde = "0.8" tokio = "1.23" async-tungstenite = "0.16" prost-build = "0.9" @@ -20,3 +25,6 @@ bytes = "1" async-std = "1" rayon = "1" serde = "1" +cfg-if = "1" +bincode = "1.3" +pin-project-lite = "0.2" diff --git a/serio/Cargo.toml b/serio/Cargo.toml new file mode 100644 index 0000000..4081e95 --- /dev/null +++ b/serio/Cargo.toml @@ -0,0 +1,33 @@ +[package] +name = "serio" +version = "0.1.0" +edition = "2021" + +[features] +default = ["compat", "channel", "codec", "bincode"] +compat = ["dep:futures-sink"] +channel = ["dep:futures-channel"] +codec = ["dep:tokio-util"] +bincode = ["dep:bincode"] + +[dependencies] +bytes.workspace = true +serde.workspace = true +pin-project-lite.workspace = true +futures-core.workspace = true +futures-channel = { workspace = true, optional = true } +futures-sink = { workspace = true, optional = true } +futures-util = { workspace = true, features = ["bilock", "unstable"] } +tokio-util = { workspace = true, features = ["codec"], optional = true } +bincode = { workspace = true, optional = true } + +[dev-dependencies] +futures.workspace = true +serde = { workspace = true, features = ["derive"] } +tokio = { workspace = true, features = ["full"] } +tokio-util = { workspace = true, features = ["codec"] } + +[[example]] +name = "tokio_codec" +path = "examples/tokio_codec.rs" +required-features = ["codec"] diff --git a/serio/LICENSE-APACHE b/serio/LICENSE-APACHE new file mode 100644 index 0000000..23096e2 --- /dev/null +++ b/serio/LICENSE-APACHE @@ -0,0 +1,203 @@ + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + +TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + +1. Definitions. + + "License" shall mean the terms and conditions for use, reproduction, + and distribution as defined by Sections 1 through 9 of this document. + + "Licensor" shall mean the copyright owner or entity authorized by + the copyright owner that is granting the License. + + "Legal Entity" shall mean the union of the acting entity and all + other entities that control, are controlled by, or are under common + control with that entity. For the purposes of this definition, + "control" means (i) the power, direct or indirect, to cause the + direction or management of such entity, whether by contract or + otherwise, or (ii) ownership of fifty percent (50%) or more of the + outstanding shares, or (iii) beneficial ownership of such entity. + + "You" (or "Your") shall mean an individual or Legal Entity + exercising permissions granted by this License. + + "Source" form shall mean the preferred form for making modifications, + including but not limited to software source code, documentation + source, and configuration files. + + "Object" form shall mean any form resulting from mechanical + transformation or translation of a Source form, including but + not limited to compiled object code, generated documentation, + and conversions to other media types. + + "Work" shall mean the work of authorship, whether in Source or + Object form, made available under the License, as indicated by a + copyright notice that is included in or attached to the work + (an example is provided in the Appendix below). + + "Derivative Works" shall mean any work, whether in Source or Object + form, that is based on (or derived from) the Work and for which the + editorial revisions, annotations, elaborations, or other modifications + represent, as a whole, an original work of authorship. For the purposes + of this License, Derivative Works shall not include works that remain + separable from, or merely link (or bind by name) to the interfaces of, + the Work and Derivative Works thereof. + + "Contribution" shall mean any work of authorship, including + the original version of the Work and any modifications or additions + to that Work or Derivative Works thereof, that is intentionally + submitted to Licensor for inclusion in the Work by the copyright owner + or by an individual or Legal Entity authorized to submit on behalf of + the copyright owner. For the purposes of this definition, "submitted" + means any form of electronic, verbal, or written communication sent + to the Licensor or its representatives, including but not limited to + communication on electronic mailing lists, source code control systems, + and issue tracking systems that are managed by, or on behalf of, the + Licensor for the purpose of discussing and improving the Work, but + excluding communication that is conspicuously marked or otherwise + designated in writing by the copyright owner as "Not a Contribution." + + "Contributor" shall mean Licensor and any individual or Legal Entity + on behalf of whom a Contribution has been received by Licensor and + subsequently incorporated within the Work. + +2. Grant of Copyright License. Subject to the terms and conditions of + this License, each Contributor hereby grants to You a perpetual, + worldwide, non-exclusive, no-charge, royalty-free, irrevocable + copyright license to reproduce, prepare Derivative Works of, + publicly display, publicly perform, sublicense, and distribute the + Work and such Derivative Works in Source or Object form. + +3. Grant of Patent License. Subject to the terms and conditions of + this License, each Contributor hereby grants to You a perpetual, + worldwide, non-exclusive, no-charge, royalty-free, irrevocable + (except as stated in this section) patent license to make, have made, + use, offer to sell, sell, import, and otherwise transfer the Work, + where such license applies only to those patent claims licensable + by such Contributor that are necessarily infringed by their + Contribution(s) alone or by combination of their Contribution(s) + with the Work to which such Contribution(s) was submitted. If You + institute patent litigation against any entity (including a + cross-claim or counterclaim in a lawsuit) alleging that the Work + or a Contribution incorporated within the Work constitutes direct + or contributory patent infringement, then any patent licenses + granted to You under this License for that Work shall terminate + as of the date such litigation is filed. + +4. Redistribution. You may reproduce and distribute copies of the + Work or Derivative Works thereof in any medium, with or without + modifications, and in Source or Object form, provided that You + meet the following conditions: + + (a) You must give any other recipients of the Work or + Derivative Works a copy of this License; and + + (b) You must cause any modified files to carry prominent notices + stating that You changed the files; and + + (c) You must retain, in the Source form of any Derivative Works + that You distribute, all copyright, patent, trademark, and + attribution notices from the Source form of the Work, + excluding those notices that do not pertain to any part of + the Derivative Works; and + + (d) If the Work includes a "NOTICE" text file as part of its + distribution, then any Derivative Works that You distribute must + include a readable copy of the attribution notices contained + within such NOTICE file, excluding those notices that do not + pertain to any part of the Derivative Works, in at least one + of the following places: within a NOTICE text file distributed + as part of the Derivative Works; within the Source form or + documentation, if provided along with the Derivative Works; or, + within a display generated by the Derivative Works, if and + wherever such third-party notices normally appear. The contents + of the NOTICE file are for informational purposes only and + do not modify the License. You may add Your own attribution + notices within Derivative Works that You distribute, alongside + or as an addendum to the NOTICE text from the Work, provided + that such additional attribution notices cannot be construed + as modifying the License. + + You may add Your own copyright statement to Your modifications and + may provide additional or different license terms and conditions + for use, reproduction, or distribution of Your modifications, or + for any such Derivative Works as a whole, provided Your use, + reproduction, and distribution of the Work otherwise complies with + the conditions stated in this License. + +5. Submission of Contributions. Unless You explicitly state otherwise, + any Contribution intentionally submitted for inclusion in the Work + by You to the Licensor shall be under the terms and conditions of + this License, without any additional terms or conditions. + Notwithstanding the above, nothing herein shall supersede or modify + the terms of any separate license agreement you may have executed + with Licensor regarding such Contributions. + +6. Trademarks. This License does not grant permission to use the trade + names, trademarks, service marks, or product names of the Licensor, + except as required for reasonable and customary use in describing the + origin of the Work and reproducing the content of the NOTICE file. + +7. Disclaimer of Warranty. Unless required by applicable law or + agreed to in writing, Licensor provides the Work (and each + Contributor provides its Contributions) on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or + implied, including, without limitation, any warranties or conditions + of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A + PARTICULAR PURPOSE. You are solely responsible for determining the + appropriateness of using or redistributing the Work and assume any + risks associated with Your exercise of permissions under this License. + +8. Limitation of Liability. In no event and under no legal theory, + whether in tort (including negligence), contract, or otherwise, + unless required by applicable law (such as deliberate and grossly + negligent acts) or agreed to in writing, shall any Contributor be + liable to You for damages, including any direct, indirect, special, + incidental, or consequential damages of any character arising as a + result of this License or out of the use or inability to use the + Work (including but not limited to damages for loss of goodwill, + work stoppage, computer failure or malfunction, or any and all + other commercial damages or losses), even if such Contributor + has been advised of the possibility of such damages. + +9. Accepting Warranty or Additional Liability. While redistributing + the Work or Derivative Works thereof, You may choose to offer, + and charge a fee for, acceptance of support, warranty, indemnity, + or other liability obligations and/or rights consistent with this + License. However, in accepting such obligations, You may act only + on Your own behalf and on Your sole responsibility, not on behalf + of any other Contributor, and only if You agree to indemnify, + defend, and hold each Contributor harmless for any liability + incurred by, or claims asserted against, such Contributor by reason + of your accepting any such warranty or additional liability. + +END OF TERMS AND CONDITIONS + +APPENDIX: How to apply the Apache License to your work. + + To apply the Apache License to your work, attach the following + boilerplate notice, with the fields enclosed by brackets "[]" + replaced with your own identifying information. (Don't include + the brackets!) The text should be enclosed in the appropriate + comment syntax for the file format. We also recommend that a + file or class name and description of purpose be included on the + same "printed page" as the copyright notice for easier + identification within third-party archives. + +Copyright (c) 2016 Alex Crichton +Copyright (c) 2017 The Tokio Authors +Copyright (c) 2024 The TLSNotary authors + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. \ No newline at end of file diff --git a/serio/LICENSE-MIT b/serio/LICENSE-MIT new file mode 100644 index 0000000..9b51d6d --- /dev/null +++ b/serio/LICENSE-MIT @@ -0,0 +1,27 @@ +Copyright (c) 2016 Alex Crichton +Copyright (c) 2017 The Tokio Authors +Copyright (c) 2024 The TLSNotary authors + +Permission is hereby granted, free of charge, to any +person obtaining a copy of this software and associated +documentation files (the "Software"), to deal in the +Software without restriction, including without +limitation the rights to use, copy, modify, merge, +publish, distribute, sublicense, and/or sell copies of +the Software, and to permit persons to whom the Software +is furnished to do so, subject to the following +conditions: + +The above copyright notice and this permission notice +shall be included in all copies or substantial portions +of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF +ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED +TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A +PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT +SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY +CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION +OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR +IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER +DEALINGS IN THE SOFTWARE. \ No newline at end of file diff --git a/serio/README.md b/serio/README.md new file mode 100644 index 0000000..fef3f80 --- /dev/null +++ b/serio/README.md @@ -0,0 +1,11 @@ +# serio + +This crate provides the `Sink` and `Stream` traits which are similar to `futures::Sink` and `futures::Stream` except they work with *any* serializable types. + +Much of the functionality from this crate was either adapted or directly copied from the [`futures`](https://github.com/rust-lang/futures-rs/) project. Inspiration was also taken from the [`tokio-serde`](https://crates.io/crates/tokio-serde) crate. + +# License + +Licensed under either of Apache License, Version 2.0 or MIT license at your option. + +Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions. \ No newline at end of file diff --git a/serio/examples/tokio_codec.rs b/serio/examples/tokio_codec.rs new file mode 100644 index 0000000..6709cb3 --- /dev/null +++ b/serio/examples/tokio_codec.rs @@ -0,0 +1,47 @@ +use serde::{Deserialize, Serialize}; +use serio::{ + codec::{Bincode, Framed}, + IoSink, IoStream, SinkExt as _, StreamExt as _, +}; +use std::io::Result; +use tokio::io::duplex; +use tokio_util::codec::LengthDelimitedCodec; + +#[derive(Serialize, Deserialize)] +struct Ping(String); + +#[derive(Serialize, Deserialize)] +struct Pong(u32); + +#[tokio::main] +async fn main() { + let (a, b) = duplex(1024); + + let a = LengthDelimitedCodec::builder().new_framed(a); + let b = LengthDelimitedCodec::builder().new_framed(b); + + let a = Framed::new(a, Bincode::default()); + let b = Framed::new(b, Bincode::default()); + + tokio::try_join!(alice(a), bob(b)).unwrap(); +} + +async fn alice(mut io: T) -> Result<()> { + io.send(Ping("hello bob!".to_string())).await?; + println!("alice: sent ping"); + + let Pong(num) = io.next().await.unwrap()?; + println!("alice: received pong {num}"); + + Ok(()) +} + +async fn bob(mut io: T) -> Result<()> { + let Ping(msg) = io.next().await.unwrap()?; + println!("bob: received ping \"{msg}\""); + + io.send(Pong(42)).await?; + println!("bob: sent pong"); + + Ok(()) +} diff --git a/serio/src/channel.rs b/serio/src/channel.rs new file mode 100644 index 0000000..d9302b5 --- /dev/null +++ b/serio/src/channel.rs @@ -0,0 +1,192 @@ +//! Memory channels for sending and receiving serializable types. Useful for testing. + +use std::{ + any::Any, + io::{Error, ErrorKind}, + pin::Pin, + task::{Context, Poll}, +}; + +use futures_channel::mpsc; +use futures_core::Stream as _; +use futures_sink::Sink as _; + +use crate::{Deserialize, Serialize, Sink, Stream}; + +type Item = Box; + +/// A memory sink that can be used to send any serializable type to the receiver. +pub struct MemorySink(mpsc::Sender); + +impl Sink for MemorySink { + type Error = Error; + + fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll> { + Pin::new(&mut self.0) + .poll_ready(cx) + .map_err(|e| Error::new(ErrorKind::ConnectionAborted, e)) + } + + fn start_send( + mut self: Pin<&mut Self>, + item: Item, + ) -> Result<(), Self::Error> { + Pin::new(&mut self.0) + .start_send(Box::new(item)) + .map_err(|e| Error::new(ErrorKind::ConnectionAborted, e)) + } + + fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll> { + Pin::new(&mut self.0) + .poll_flush(cx) + .map_err(|e| Error::new(ErrorKind::ConnectionAborted, e)) + } + + fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll> { + Pin::new(&mut self.0) + .poll_close(cx) + .map_err(|e| Error::new(ErrorKind::ConnectionAborted, e)) + } +} + +/// A memory stream that can be used to receive any deserializable type from the sender. +pub struct MemoryStream(mpsc::Receiver); + +impl Stream for MemoryStream { + type Error = Error; + + fn poll_next( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + ) -> Poll>> { + Pin::new(&mut self.0).poll_next(cx).map(|item| { + item.map(|item| { + item.downcast().map(|item| *item).map_err(|_| { + Error::new(ErrorKind::InvalidData, "sender sent an unexpected type") + }) + }) + }) + } +} + +/// Creates a new memory channel with the specified buffer size. +pub fn channel(buffer: usize) -> (MemorySink, MemoryStream) { + let (sender, receiver) = mpsc::channel(buffer); + (MemorySink(sender), MemoryStream(receiver)) +} + +/// A memory duplex that can be used to send and receive any serializable types. +pub struct MemoryDuplex { + sink: MemorySink, + stream: MemoryStream, +} + +impl MemoryDuplex { + /// Returns the inner sink and stream. + pub fn into_inner(self) -> (MemorySink, MemoryStream) { + (self.sink, self.stream) + } + + /// Returns a reference to the inner sink. + pub fn sink_mut(&mut self) -> &mut MemorySink { + &mut self.sink + } + + /// Returns a reference to the inner stream. + pub fn stream_mut(&mut self) -> &mut MemoryStream { + &mut self.stream + } +} + +impl Sink for MemoryDuplex { + type Error = Error; + + fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll> { + Pin::new(&mut self.sink).poll_ready(cx) + } + + fn start_send( + mut self: Pin<&mut Self>, + item: Item, + ) -> Result<(), Self::Error> { + Pin::new(&mut self.sink).start_send(item) + } + + fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll> { + Pin::new(&mut self.sink).poll_flush(cx) + } + + fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll> { + Pin::new(&mut self.sink).poll_close(cx) + } +} + +impl Stream for MemoryDuplex { + type Error = Error; + + fn poll_next( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + ) -> Poll>> { + Pin::new(&mut self.stream).poll_next(cx) + } +} + +/// Creates a new memory duplex with the specified buffer size. +pub fn duplex(buffer: usize) -> (MemoryDuplex, MemoryDuplex) { + let (a, b) = channel(buffer); + let (c, d) = channel(buffer); + ( + MemoryDuplex { sink: a, stream: d }, + MemoryDuplex { sink: c, stream: b }, + ) +} + +#[cfg(test)] +mod tests { + use super::*; + + use crate::{SinkExt, StreamExt}; + + #[test] + fn test_channel() { + let (mut sink, mut stream) = channel(1); + + futures::executor::block_on(async { + sink.send(42u8).await.unwrap(); + assert_eq!(stream.next::().await.unwrap().unwrap(), 42); + }) + } + + #[test] + #[should_panic] + fn test_channel_type_mismatch() { + let (mut sink, mut stream) = channel(1); + + futures::executor::block_on(async { + sink.send(42u16).await.unwrap(); + stream.next::().await.unwrap().unwrap(); + }) + } + + #[test] + fn test_duplex() { + let (mut a, mut b) = duplex(1); + + futures::executor::block_on(async { + a.send(42u8).await.unwrap(); + assert_eq!(b.next::().await.unwrap().unwrap(), 42); + }) + } + + #[test] + #[should_panic] + fn test_duplex_type_mismatch() { + let (mut a, mut b) = duplex(1); + + futures::executor::block_on(async { + a.send(42u16).await.unwrap(); + b.next::().await.unwrap().unwrap(); + }) + } +} diff --git a/serio/src/codec.rs b/serio/src/codec.rs new file mode 100644 index 0000000..c2b46b3 --- /dev/null +++ b/serio/src/codec.rs @@ -0,0 +1,172 @@ +//! Utilities for converting framed transports to streams and sinks using a codec. + +use std::{ + io::{Error, ErrorKind}, + pin::Pin, + task::{ready, Context, Poll}, +}; + +use bytes::{Bytes, BytesMut}; +use futures_core::stream::TryStream; + +use crate::{Deserialize, Serialize, Sink, Stream}; + +/// A serializer. +pub trait Serializer { + /// The error type. + type Error; + + /// Serializes `item` into a buffer. + fn serialize(&mut self, item: &T) -> Result; +} + +/// A deserializer. +pub trait Deserializer { + /// The error type. + type Error; + + /// Deserializes a buffer into a value. + fn deserialize(&mut self, buf: &BytesMut) -> Result; +} + +#[cfg(feature = "bincode")] +mod bincode_impl { + use super::*; + use bincode::{deserialize, serialize}; + + /// A bincode codec. + #[derive(Default, Clone)] + pub struct Bincode; + + impl Serializer for Bincode { + type Error = bincode::Error; + + fn serialize(&mut self, item: &T) -> Result { + Ok(Bytes::from(serialize(item)?)) + } + } + + impl Deserializer for Bincode { + type Error = bincode::Error; + + fn deserialize(&mut self, buf: &BytesMut) -> Result { + Ok(deserialize(buf)?) + } + } +} + +#[cfg(feature = "bincode")] +pub use bincode_impl::Bincode; + +/// A framed transport. +pub struct Framed { + inner: T, + codec: C, +} + +impl Framed { + /// Creates a new `Framed` with the given transport and codec. + pub fn new(inner: T, codec: C) -> Self { + Self { inner, codec } + } +} + +impl Sink for Framed +where + T: futures_sink::Sink + Unpin, + C: Serializer + Unpin, + ::Error: Into>, +{ + type Error = Error; + + fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll> { + Pin::new(&mut self.inner).poll_ready(cx) + } + + fn start_send( + mut self: std::pin::Pin<&mut Self>, + item: I, + ) -> Result<(), Self::Error> { + let buf = self + .codec + .serialize(&item) + .map_err(|e| Error::new(ErrorKind::InvalidData, e))?; + + Pin::new(&mut self.inner).start_send(buf) + } + + fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll> { + Pin::new(&mut self.inner).poll_flush(cx) + } + + fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll> { + Pin::new(&mut self.inner).poll_close(cx) + } +} + +impl Stream for Framed +where + T: TryStream + Unpin, + C: Deserializer + Unpin, + ::Error: Into>, +{ + type Error = Error; + + fn poll_next( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + ) -> Poll>> { + let Some(buf) = ready!(Pin::new(&mut self.inner).try_poll_next(cx)) else { + return Poll::Ready(None); + }; + + let item = self + .codec + .deserialize(&buf?) + .map_err(|e| Error::new(ErrorKind::InvalidData, e)); + + Poll::Ready(Some(item)) + } +} + +#[cfg(test)] +mod tests { + use serde::{Deserialize, Serialize}; + use tokio::io::duplex; + use tokio_util::codec::LengthDelimitedCodec; + + use crate::{SinkExt, StreamExt}; + + use super::*; + + #[derive(Serialize, Deserialize)] + struct Ping; + + #[derive(Serialize, Deserialize)] + struct Pong; + + #[test] + fn test_framed() { + let (a, b) = duplex(1024); + + let a = LengthDelimitedCodec::builder().new_framed(a); + let b = LengthDelimitedCodec::builder().new_framed(b); + + let mut a = Framed::new(a, Bincode::default()); + let mut b = Framed::new(b, Bincode::default()); + + let a = async { + a.send(Ping).await.unwrap(); + a.next::().await.unwrap().unwrap(); + }; + + let b = async { + b.next::().await.unwrap().unwrap(); + b.send(Pong).await.unwrap(); + }; + + futures::executor::block_on(async { + futures::join!(a, b); + }); + } +} diff --git a/serio/src/future.rs b/serio/src/future.rs new file mode 100644 index 0000000..dffbfc0 --- /dev/null +++ b/serio/src/future.rs @@ -0,0 +1,10 @@ +use std::future::Future; + +// Just a helper function to ensure the futures we're returning all have the +// right implementations. +pub(crate) fn assert_future(future: F) -> F +where + F: Future, +{ + future +} diff --git a/serio/src/lib.rs b/serio/src/lib.rs new file mode 100644 index 0000000..bbf0867 --- /dev/null +++ b/serio/src/lib.rs @@ -0,0 +1,36 @@ +#![doc = include_str!("../README.md")] +#![deny(missing_docs, unreachable_pub, unused_must_use)] +#![deny(clippy::all)] + +#[cfg(feature = "channel")] +pub mod channel; +#[cfg(feature = "codec")] +pub mod codec; +pub(crate) mod future; +pub mod sink; +pub mod stream; + +#[cfg(feature = "codec")] +pub use codec::{Deserializer, Framed, Serializer}; +pub use sink::{IoSink, Sink, SinkExt}; +pub use stream::{IoStream, Stream, StreamExt}; + +/// A serializable type. +pub trait Serialize: serde::Serialize + Send + Sync + Unpin + 'static {} + +impl Serialize for T where T: serde::Serialize + Send + Sync + Unpin + 'static {} + +/// A deserializable type. +pub trait Deserialize: serde::de::DeserializeOwned + Send + Sync + Unpin + 'static {} + +impl Deserialize for T where T: serde::de::DeserializeOwned + Send + Sync + Unpin + 'static {} + +/// A duplex. +pub trait Duplex: Sink + Stream {} + +impl Duplex for T where T: Sink + Stream {} + +/// A duplex with a `std::io::Error` error type. +pub trait IoDuplex: Duplex {} + +impl IoDuplex for T where T: Duplex {} diff --git a/serio/src/sink.rs b/serio/src/sink.rs new file mode 100644 index 0000000..95239ea --- /dev/null +++ b/serio/src/sink.rs @@ -0,0 +1,387 @@ +//! Sink types and traits. + +use std::{ + future::Future, + marker::PhantomData, + ops::DerefMut, + pin::Pin, + task::{ready, Context, Poll}, +}; + +use crate::{future::assert_future, Serialize}; + +/// A sink with an error type of `std::io::Error`. +pub trait IoSink: Sink {} + +impl IoSink for T where T: Sink {} + +/// A sink which accepts any item which implements `Serialize`. +/// +/// This trait is similar to [`futures::Sink`](https://docs.rs/futures/latest/futures/sink/trait.Sink.html), +/// but facilitates sending of any serializable type instead of a single type. +#[must_use = "sinks do nothing unless polled"] +pub trait Sink { + /// The type of value produced by the sink when an error occurs. + type Error; + + /// Attempts to prepare the `Sink` to receive a value. + /// + /// This method must be called and return `Poll::Ready(Ok(()))` prior to + /// each call to `start_send`. + /// + /// This method returns `Poll::Ready` once the underlying sink is ready to + /// receive data. If this method returns `Poll::Pending`, the current task + /// is registered to be notified (via `cx.waker().wake_by_ref()`) when `poll_ready` + /// should be called again. + /// + /// In most cases, if the sink encounters an error, the sink will + /// permanently be unable to receive items. + fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll>; + + /// Begin the process of sending a value to the sink. + /// Each call to this function must be preceded by a successful call to + /// `poll_ready` which returned `Poll::Ready(Ok(()))`. + /// + /// As the name suggests, this method only *begins* the process of sending + /// the item. If the sink employs buffering, the item isn't fully processed + /// until the buffer is fully flushed. Since sinks are designed to work with + /// asynchronous I/O, the process of actually writing out the data to an + /// underlying object takes place asynchronously. **You *must* use + /// `poll_flush` or `poll_close` in order to guarantee completion of a + /// send**. + /// + /// Implementations of `poll_ready` and `start_send` will usually involve + /// flushing behind the scenes in order to make room for new messages. + /// It is only necessary to call `poll_flush` if you need to guarantee that + /// *all* of the items placed into the `Sink` have been sent. + /// + /// In most cases, if the sink encounters an error, the sink will + /// permanently be unable to receive items. + fn start_send(self: Pin<&mut Self>, item: Item) -> Result<(), Self::Error>; + + /// Flush any remaining output from this sink. + /// + /// Returns `Poll::Ready(Ok(()))` when no buffered items remain. If this + /// value is returned then it is guaranteed that all previous values sent + /// via `start_send` have been flushed. + /// + /// Returns `Poll::Pending` if there is more work left to do, in which + /// case the current task is scheduled (via `cx.waker().wake_by_ref()`) to wake up when + /// `poll_flush` should be called again. + /// + /// In most cases, if the sink encounters an error, the sink will + /// permanently be unable to receive items. + fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll>; + + /// Flush any remaining output and close this sink, if necessary. + /// + /// Returns `Poll::Ready(Ok(()))` when no buffered items remain and the sink + /// has been successfully closed. + /// + /// Returns `Poll::Pending` if there is more work left to do, in which + /// case the current task is scheduled (via `cx.waker().wake_by_ref()`) to wake up when + /// `poll_close` should be called again. + /// + /// If this function encounters an error, the sink should be considered to + /// have failed permanently, and no more `Sink` methods should be called. + fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll>; +} + +impl Sink for &mut S { + type Error = S::Error; + + fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll> { + Pin::new(&mut **self).poll_ready(cx) + } + + fn start_send( + mut self: Pin<&mut Self>, + item: Item, + ) -> Result<(), Self::Error> { + Pin::new(&mut **self).start_send(item) + } + + fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll> { + Pin::new(&mut **self).poll_flush(cx) + } + + fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll> { + Pin::new(&mut **self).poll_close(cx) + } +} + +impl

Sink for Pin

+where + P: DerefMut + Unpin, + P::Target: Sink, +{ + type Error = ::Error; + + fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll> { + self.get_mut().as_mut().poll_ready(cx) + } + + fn start_send(self: Pin<&mut Self>, item: Item) -> Result<(), Self::Error> { + self.get_mut().as_mut().start_send(item) + } + + fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll> { + self.get_mut().as_mut().poll_flush(cx) + } + + fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll> { + self.get_mut().as_mut().poll_close(cx) + } +} + +/// An extension trait for Sinks that provides a variety of convenient functions. +pub trait SinkExt: Sink { + /// Close the sink. + fn close(&mut self) -> Close<'_, Self> + where + Self: Unpin, + { + assert_future::, _>(Close::new(self)) + } + + /// A future that completes after the given item has been fully processed + /// into the sink, including flushing. + /// + /// Note that, **because of the flushing requirement, it is usually better + /// to batch together items to send via `feed` or `send_all`, + /// rather than flushing between each item.** + fn send(&mut self, item: Item) -> Send<'_, Self, Item> + where + Self: Unpin, + { + assert_future::, _>(Send::new(self, item)) + } + + /// A future that completes after the given item has been received + /// by the sink. + /// + /// Unlike `send`, the returned future does not flush the sink. + /// It is the caller's responsibility to ensure all pending items + /// are processed, which can be done via `flush` or `close`. + fn feed(&mut self, item: Item) -> Feed<'_, Self, Item> + where + Self: Unpin, + { + assert_future::, _>(Feed::new(self, item)) + } + + /// A future that completes after the sink has been flushed. + fn flush(&mut self) -> Flush<'_, Self> + where + Self: Unpin, + { + assert_future::, _>(Flush::new(self)) + } + + /// Convert this sink into a `futures::Sink`. + #[cfg(feature = "compat")] + fn into_sink(self) -> IntoSink + where + Self: Sized, + { + assert_futures_sink(IntoSink::new(self)) + } +} + +impl SinkExt for S {} + +/// Future for the [`close`](SinkExt::close) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Close<'a, Si: ?Sized> { + sink: &'a mut Si, +} + +impl Unpin for Close<'_, Si> {} + +/// A future that completes when the sink has finished closing. +/// +/// The sink itself is returned after closing is complete. +impl<'a, Si: Sink + Unpin + ?Sized> Close<'a, Si> { + fn new(sink: &'a mut Si) -> Self { + Self { sink } + } +} + +impl Future for Close<'_, Si> { + type Output = Result<(), Si::Error>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll { + Pin::new(&mut self.sink).poll_close(cx) + } +} + +/// Future for the [`send`](SinkExt::send) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Send<'a, Si: ?Sized, Item> { + feed: Feed<'a, Si, Item>, +} + +// Pinning is never projected to children. +impl Unpin for Send<'_, Si, Item> {} + +impl<'a, Si: Sink + Unpin + ?Sized, Item> Send<'a, Si, Item> { + fn new(sink: &'a mut Si, item: Item) -> Self { + Self { + feed: Feed::new(sink, item), + } + } +} + +impl Future for Send<'_, Si, Item> { + type Output = Result<(), Si::Error>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll { + let this = &mut *self; + + if this.feed.is_item_pending() { + ready!(Pin::new(&mut this.feed).poll(cx))?; + debug_assert!(!this.feed.is_item_pending()); + } + + // We're done sending the item, but want to block on flushing the + // sink. + ready!(this.feed.sink_pin_mut().poll_flush(cx))?; + + Poll::Ready(Ok(())) + } +} + +/// Future for the [`feed`](SinkExt::feed) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Feed<'a, Si: ?Sized, Item> { + sink: &'a mut Si, + item: Option, +} + +// Pinning is never projected to children. +impl Unpin for Feed<'_, Si, Item> {} + +impl<'a, Si: Sink + Unpin + ?Sized, Item> Feed<'a, Si, Item> { + fn new(sink: &'a mut Si, item: Item) -> Self { + Feed { + sink, + item: Some(item), + } + } + + fn sink_pin_mut(&mut self) -> Pin<&mut Si> { + Pin::new(self.sink) + } + + fn is_item_pending(&self) -> bool { + self.item.is_some() + } +} + +impl Future for Feed<'_, Si, Item> { + type Output = Result<(), Si::Error>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll { + let this = self.get_mut(); + let mut sink = Pin::new(&mut this.sink); + ready!(sink.as_mut().poll_ready(cx))?; + let item = this.item.take().expect("polled Feed after completion"); + sink.as_mut().start_send(item)?; + Poll::Ready(Ok(())) + } +} + +/// Future for the [`flush`](SinkExt::flush) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Flush<'a, Si: ?Sized> { + sink: &'a mut Si, +} + +impl Unpin for Flush<'_, Si> {} + +impl<'a, Si: Sink + Unpin + ?Sized> Flush<'a, Si> { + fn new(sink: &'a mut Si) -> Self { + Self { sink } + } +} + +impl Future for Flush<'_, Si> { + type Output = Result<(), Si::Error>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll { + Pin::new(&mut self.sink).poll_flush(cx) + } +} + +#[cfg(feature = "compat")] +mod compat { + use super::*; + + pin_project_lite::pin_project! { + /// Wraps a sink and provides a `futures::Sink` implementation. + pub struct IntoSink { + #[pin] + sink: Si, + _pd: PhantomData, + } + } + + impl IntoSink { + pub(super) fn new(sink: Si) -> Self { + Self { + sink, + _pd: PhantomData, + } + } + + /// Returns a reference to the inner sink. + pub fn sink(&self) -> &Si { + &self.sink + } + + /// Returns a mutable reference to the inner sink. + pub fn sink_mut(&mut self) -> &mut Si { + &mut self.sink + } + + /// Returns the inner sink. + pub fn into_inner(self) -> Si { + self.sink + } + } + + impl futures_sink::Sink for IntoSink + where + Si: Sink, + Item: Serialize, + { + type Error = Si::Error; + + fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll> { + self.project().sink.poll_ready(cx) + } + + fn start_send(self: Pin<&mut Self>, item: Item) -> Result<(), Self::Error> { + self.project().sink.start_send(item) + } + + fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll> { + self.project().sink.poll_flush(cx) + } + + fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll> { + self.project().sink.poll_close(cx) + } + } +} + +#[cfg(feature = "compat")] +pub use compat::IntoSink; + +pub(crate) fn assert_futures_sink, Item>(sink: S) -> S { + sink +} diff --git a/serio/src/stream.rs b/serio/src/stream.rs new file mode 100644 index 0000000..90b4b5b --- /dev/null +++ b/serio/src/stream.rs @@ -0,0 +1,331 @@ +//! Stream types and traits. + +use std::{ + future::Future, + marker::PhantomData, + ops::DerefMut, + pin::Pin, + task::{ready, Context, Poll}, +}; + +use futures_core::FusedFuture; + +use crate::{future::assert_future, Deserialize}; + +/// A stream with an error type of `std::io::Error`. +pub trait IoStream: Stream {} + +impl IoStream for T where T: Stream {} + +/// A stream producing any kind of value which implements `Deserialize`. +/// +/// This trait is similar to [`futures::Stream`](https://docs.rs/futures/latest/futures/stream/trait.Stream.html), +/// but facilitates receiving of any deserializable type instead of a single type. +#[must_use = "streams do nothing unless polled"] +pub trait Stream { + /// The type of value produced by the stream when an error occurs. + type Error; + + /// Attempt to pull out the next value of this stream, registering the + /// current task for wakeup if the value is not yet available, and returning + /// `None` if the stream is exhausted. + /// + /// # Return value + /// + /// There are several possible return values, each indicating a distinct + /// stream state: + /// + /// - `Poll::Pending` means that this stream's next value is not ready + /// yet. Implementations will ensure that the current task will be notified + /// when the next value may be ready. + /// + /// - `Poll::Ready(Some(val))` means that the stream has successfully + /// produced a value, `val`, and may produce further values on subsequent + /// `poll_next` calls. + /// + /// - `Poll::Ready(None)` means that the stream has terminated, and + /// `poll_next` should not be invoked again. + fn poll_next( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + ) -> Poll>>; + + /// Returns the bounds on the remaining length of the stream. + /// + /// Specifically, `size_hint()` returns a tuple where the first element + /// is the lower bound, and the second element is the upper bound. + /// + /// The second half of the tuple that is returned is an [`Option`]`<`[`usize`]`>`. + /// A [`None`] here means that either there is no known upper bound, or the + /// upper bound is larger than [`usize`]. + /// + /// # Implementation notes + /// + /// It is not enforced that a stream implementation yields the declared + /// number of elements. A buggy stream may yield less than the lower bound + /// or more than the upper bound of elements. + /// + /// `size_hint()` is primarily intended to be used for optimizations such as + /// reserving space for the elements of the stream, but must not be + /// trusted to e.g., omit bounds checks in unsafe code. An incorrect + /// implementation of `size_hint()` should not lead to memory safety + /// violations. + /// + /// That said, the implementation should provide a correct estimation, + /// because otherwise it would be a violation of the trait's protocol. + /// + /// The default implementation returns `(0, `[`None`]`)` which is correct for any + /// stream. + #[inline] + fn size_hint(&self) -> (usize, Option) { + (0, None) + } +} + +impl Stream for &mut S { + type Error = S::Error; + + fn poll_next( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + ) -> Poll>> { + S::poll_next(Pin::new(&mut **self), cx) + } + + fn size_hint(&self) -> (usize, Option) { + (**self).size_hint() + } +} + +impl

Stream for Pin

+where + P: DerefMut + Unpin, + P::Target: Stream, +{ + type Error = ::Error; + + fn poll_next( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + ) -> Poll>> { + self.get_mut().as_mut().poll_next(cx) + } + + fn size_hint(&self) -> (usize, Option) { + (**self).size_hint() + } +} + +/// A stream which tracks whether or not the underlying stream +/// should no longer be polled. +/// +/// `is_terminated` will return `true` if a future should no longer be polled. +/// Usually, this state occurs after `poll_next` (or `try_poll_next`) returned +/// `Poll::Ready(None)`. However, `is_terminated` may also return `true` if a +/// stream has become inactive and can no longer make progress and should be +/// ignored or dropped rather than being polled again. +pub trait FusedStream: Stream { + /// Returns `true` if the stream should no longer be polled. + fn is_terminated(&self) -> bool; +} + +impl FusedStream for &mut F { + fn is_terminated(&self) -> bool { + ::is_terminated(&**self) + } +} + +impl

FusedStream for Pin

+where + P: DerefMut + Unpin, + P::Target: FusedStream, +{ + fn is_terminated(&self) -> bool { + ::is_terminated(&**self) + } +} + +/// An extension trait for Streams that provides a variety of convenient functions. +pub trait StreamExt: Stream { + /// Creates a future that resolves to the next item in the stream. + /// + /// Note that because `next` doesn't take ownership over the stream, + /// the [`Stream`] type must be [`Unpin`]. If you want to use `next` with a + /// [`!Unpin`](Unpin) stream, you'll first have to pin the stream. This can + /// be done by boxing the stream using [`Box::pin`] or + /// pinning it to the stack using the `pin_mut!` macro from the `pin_utils` + /// crate. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// + /// let mut stream = stream::iter(1..=3); + /// + /// assert_eq!(stream.next().await, Some(1)); + /// assert_eq!(stream.next().await, Some(2)); + /// assert_eq!(stream.next().await, Some(3)); + /// assert_eq!(stream.next().await, None); + /// # }); + /// ``` + fn next(&mut self) -> Next<'_, Self, Item> + where + Self: Unpin, + { + assert_future::>, _>(Next::new(self)) + } + + /// Converts this stream into a `futures::Stream`. + #[cfg(feature = "compat")] + fn into_stream(self) -> IntoStream + where + Self: Sized, + { + assert_futures_stream(IntoStream::new(self)) + } + + /// A convenience method for calling [`Stream::poll_next`] on [`Unpin`] + /// stream types. + fn poll_next_unpin( + &mut self, + cx: &mut Context<'_>, + ) -> Poll>> + where + Self: Unpin, + { + Pin::new(self).poll_next(cx) + } +} + +impl StreamExt for S {} + +/// Future for the [`next`](StreamExt::next) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Next<'a, St: ?Sized, Item> { + stream: &'a mut St, + _pd: PhantomData, +} + +impl Unpin for Next<'_, St, Item> {} + +impl<'a, St: ?Sized + Stream + Unpin, Item> Next<'a, St, Item> { + pub(super) fn new(stream: &'a mut St) -> Self { + Self { + stream, + _pd: PhantomData, + } + } +} + +impl FusedFuture for Next<'_, St, Item> { + fn is_terminated(&self) -> bool { + self.stream.is_terminated() + } +} + +impl Future for Next<'_, St, Item> { + type Output = Option>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll { + self.stream.poll_next_unpin(cx) + } +} + +#[cfg(feature = "compat")] +mod compat { + use super::*; + + pin_project_lite::pin_project! { + /// Wraps a stream and provides a `futures::Stream` implementation. + pub struct IntoStream { + #[pin] + stream: St, + _pd: PhantomData, + } + } + + impl IntoStream { + pub(super) fn new(stream: St) -> Self { + Self { + stream, + _pd: PhantomData, + } + } + + /// Returns a reference to the inner stream. + pub fn stream(&self) -> &St { + &self.stream + } + + /// Returns a mutable reference to the inner stream. + pub fn stream_mut(&mut self) -> &mut St { + &mut self.stream + } + + /// Returns the inner stream. + pub fn into_inner(self) -> St { + self.stream + } + } + + impl futures_core::Stream for IntoStream + where + St: Stream, + Item: Deserialize, + { + type Item = Result; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll> { + self.project().stream.poll_next(cx) + } + } +} + +#[cfg(feature = "compat")] +pub use compat::IntoStream; + +/// An extension trait for [`IoStream`] which provides a variety of convenient functions. +pub trait IoStreamExt: IoStream { + /// Creates a future that resolves to the next item in the stream, returning + /// an error if the stream is exhausted. + fn expect_next(&mut self) -> ExpectNext<'_, Self, Item> + where + Self: Unpin, + { + ExpectNext { + next: self.next(), + _pd: PhantomData, + } + } +} + +impl IoStreamExt for S where S: IoStream {} + +/// Future for the [`expect_next`](IoStreamExt::expect_next) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct ExpectNext<'a, St: ?Sized, Item> { + next: Next<'a, St, Item>, + _pd: PhantomData, +} + +impl Unpin for ExpectNext<'_, St, Item> {} + +impl<'a, St: ?Sized + IoStream + Unpin, Item: Deserialize> Future for ExpectNext<'a, St, Item> { + type Output = Result; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll { + match ready!(Pin::new(&mut self.next).poll(cx)) { + Some(Ok(item)) => Poll::Ready(Ok(item)), + Some(Err(err)) => Poll::Ready(Err(err)), + None => Poll::Ready(Err(std::io::ErrorKind::UnexpectedEof.into())), + } + } +} + +pub(crate) fn assert_futures_stream(stream: S) -> S { + stream +}