From 3e4ce679175651344125ace49f83e7595681cd39 Mon Sep 17 00:00:00 2001
From: Simon Hammes <simonhammes@users.noreply.github.com>
Date: Wed, 15 Feb 2023 14:55:58 +0100
Subject: [PATCH] Use rayon

---
 Cargo.lock  | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 Cargo.toml  |  1 +
 src/main.rs | 19 +++++++------------
 3 files changed, 60 insertions(+), 12 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index f0d46c5..1e2c719 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -103,6 +103,37 @@ version = "0.8.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "06ea2b9bc92be3c2baa9334a323ebca2d6f074ff852cd1d7b11064035cd3868f"
 
+[[package]]
+name = "crossbeam-deque"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "613f8cc01fe9cf1a3eb3d7f488fd2fa8388403e97039e2f73692932e291a770d"
+dependencies = [
+ "crossbeam-epoch",
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-epoch"
+version = "0.9.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b82ac4a3c2ca9c3460964f020e1402edd5753411d7737aa39c3714ad1b5420e"
+dependencies = [
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-utils"
+version = "0.8.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "248e3bacc7dc6baa3b21e405ee045c3047101a49145e7e9eca583ab4c2ca5345"
+
+[[package]]
+name = "either"
+version = "1.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "11157ac094ffbdde99aa67b23417ebdd801842852b500e395a45a9c0aac03e4a"
+
 [[package]]
 name = "futures"
 version = "0.3.30"
@@ -371,6 +402,26 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "rayon"
+version = "1.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fa7237101a77a10773db45d62004a272517633fbcc3df19d96455ede1122e051"
+dependencies = [
+ "either",
+ "rayon-core",
+]
+
+[[package]]
+name = "rayon-core"
+version = "1.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1465873a3dfdaa8ae7cb14b4383657caab0b3e8a0aa9ae8e04b044854c8dfce2"
+dependencies = [
+ "crossbeam-deque",
+ "crossbeam-utils",
+]
+
 [[package]]
 name = "redox_syscall"
 version = "0.5.1"
@@ -386,6 +437,7 @@ version = "0.1.0"
 dependencies = [
  "chrono",
  "futures",
+ "rayon",
  "tokio",
 ]
 
diff --git a/Cargo.toml b/Cargo.toml
index b8a9a9a..bf45dfb 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,4 +8,5 @@ edition = "2021"
 [dependencies]
 chrono = "0.4.23"
 futures = "0.3.26"
+rayon = "1.6.1"
 tokio = { version = "1.25.0", features = ["full"]}
diff --git a/src/main.rs b/src/main.rs
index b3a80e4..514017c 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,10 +1,10 @@
 use chrono::{DateTime, Datelike, Days, NaiveDate, NaiveTime, Weekday};
-use futures::future::join_all;
+use rayon::prelude::*;
 use std::collections::BTreeMap;
+use std::thread;
 use std::time::Duration;
 
-#[tokio::main]
-async fn main() {
+fn main() {
     println!("Hello, world!");
 
     let start = NaiveDate::from_isoywd_opt(2023, 1, Weekday::Mon)
@@ -24,13 +24,8 @@ async fn main() {
     .map(DateTime::date_naive)
     .collect();
 
-    let futures = dates.iter().map(fetch);
-
-    let result: Vec<(&NaiveDate, Vec<Response>)> = join_all(futures)
-        .await
-        .into_iter()
-        .filter_map(Result::ok)
-        .collect();
+    let result: Vec<(&NaiveDate, Vec<Response>)> =
+        dates.par_iter().map(fetch).filter_map(Result::ok).collect();
 
     let map = BTreeMap::from_iter(result);
 
@@ -43,9 +38,9 @@ struct Response {
     day: u8,
 }
 
-async fn fetch(date: &NaiveDate) -> Result<(&NaiveDate, Vec<Response>), ()> {
+fn fetch(date: &NaiveDate) -> Result<(&NaiveDate, Vec<Response>), ()> {
     println!("Sleeping...");
-    tokio::time::sleep(Duration::from_secs(1)).await;
+    thread::sleep(Duration::from_secs(1));
 
     let responses = vec![
         Response {