From e820273c8902318304f5c852d48749334878c494 Mon Sep 17 00:00:00 2001
From: finga <finga@onders.org>
Date: Sat, 23 Apr 2022 20:34:36 +0200
Subject: [PATCH] Read asynchronous from serial

Use tokio to read asynchronous from serial port.
---
 Cargo.lock  | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 Cargo.toml  |  1 +
 src/main.rs | 26 ++++++++++++++++---
 3 files changed, 98 insertions(+), 3 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 6d39586..d8ffe92 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -177,6 +177,7 @@ dependencies = [
  "env_logger",
  "log",
  "serialport",
+ "tokio",
 ]
 
 [[package]]
@@ -192,12 +193,46 @@ dependencies = [
  "memoffset",
 ]
 
+[[package]]
+name = "num_cpus"
+version = "1.13.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "19e64526ebdee182341572e50e9ad03965aa510cd94427a4549448f285e957a1"
+dependencies = [
+ "hermit-abi",
+ "libc",
+]
+
+[[package]]
+name = "pin-project-lite"
+version = "0.2.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e280fbe77cc62c91527259e9442153f4688736748d24660126286329742b4c6c"
+
 [[package]]
 name = "pkg-config"
 version = "0.3.25"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1df8c4ec4b0627e53bdf214615ad287367e482558cf84b109250b37464dc03ae"
 
+[[package]]
+name = "proc-macro2"
+version = "1.0.37"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec757218438d5fda206afc041538b2f6d889286160d649a86a24d37e1235afd1"
+dependencies = [
+ "unicode-xid",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1feb54ed693b93a84e14094943b84b7c4eae204c512b7ccb95ab0c66d278ad1"
+dependencies = [
+ "proc-macro2",
+]
+
 [[package]]
 name = "regex"
 version = "1.5.5"
@@ -232,6 +267,17 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "syn"
+version = "1.0.91"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b683b2b825c8eef438b77c36a06dc262294da3d5a5813fac20da149241dcd44d"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-xid",
+]
+
 [[package]]
 name = "termcolor"
 version = "1.1.3"
@@ -241,6 +287,34 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "tokio"
+version = "1.17.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2af73ac49756f3f7c01172e34a23e5d0216f6c32333757c2c61feb2bbff5a5ee"
+dependencies = [
+ "num_cpus",
+ "pin-project-lite",
+ "tokio-macros",
+]
+
+[[package]]
+name = "tokio-macros"
+version = "1.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b557f72f448c511a979e2564e55d74e6c4432fc96ff4f6241bc6bded342643b7"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "unicode-xid"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8ccb82d61f80a663efe1f787a51b16b5a51e3314d6ac365b08639f52387b33f3"
+
 [[package]]
 name = "winapi"
 version = "0.3.9"
diff --git a/Cargo.toml b/Cargo.toml
index 52a83f5..a1eb286 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,3 +13,4 @@ anyhow = "1.0"
 serialport = "4.1"
 log = "0.4"
 env_logger = "0.9"
+tokio = { version = "1.17", features = ["rt-multi-thread", "macros"] }
diff --git a/src/main.rs b/src/main.rs
index f062d93..66f3930 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -5,6 +5,7 @@ use std::{
     str::FromStr,
     time::Duration,
 };
+use tokio::{spawn, task::JoinHandle, try_join};
 
 #[derive(Debug)]
 enum Speed {
@@ -50,9 +51,8 @@ fn parse(input: &str) -> Result<(usize, usize, f32, Speed)> {
     ))
 }
 
-fn main() -> Result<()> {
-    env_logger::init();
-
+#[allow(clippy::unused_async, clippy::similar_names)]
+async fn listen_serial() -> Result<()> {
     let port_name = "/dev/serial0";
     let baud_rate = 9600;
 
@@ -69,3 +69,23 @@ fn main() -> Result<()> {
         let (_cps, _cpm, _radiation, _mode) = parse(line)?;
     }
 }
+
+async fn flatten<T>(handle: JoinHandle<Result<T>>) -> Result<T>
+where
+    T: Send,
+{
+    match handle.await {
+        Ok(Ok(result)) => Ok(result),
+        Ok(Err(err)) => bail!(err),
+        Err(err) => bail!(err),
+    }
+}
+
+#[tokio::main]
+async fn main() -> Result<()> {
+    env_logger::init();
+
+    try_join!(flatten(spawn(listen_serial())))?;
+
+    Ok(())
+}