Use spawn's retval instead of an Arc<Mutex<_>>

src/main.rs

@@ -4,7 +4,6 @@ use anyhow::Result;
 use async_std::fs::File;
 use async_std::prelude::*;
 use async_std::task;
-use async_std::sync::{Arc, Mutex};
 use freq::{FreqGetter, FreqMap};
 use regex::Regex;
 use std::path::PathBuf;
@@ -22,17 +21,15 @@ async fn main() -> Result<()> {
     let sym_or_num_re = Regex::new(r"[0-9!@#$%^&*()_+-=]").expect("Bad regex");
     let glb = glob("/home/igarin/workspace/**/*.rs").expect("Bad glob");
     let mut children = vec![];
-    let mut maps = Arc::new(Mutex::new(Vec::<(PathBuf, FreqMap)>::new()));
 
     for entry in glb {
         match entry {
             Ok(path) => {
                 let getter = FreqGetter::new().filter_regex(sym_or_num_re.clone());
-                let priv_maps = maps.clone();
                 let child = task::spawn(async move {
-                    let freq = get_file_freq(path.clone(), getter).await.unwrap();
-                    let mut m = priv_maps.lock().await;
-                    m.push((path, freq));
+                    get_file_freq(path.clone(), getter)
+                        .await
+                        .map(|freq| (path, freq))
                 });
                 children.push(child);
             }
@@ -41,13 +38,10 @@ async fn main() -> Result<()> {
     }
 
     for child in children {
-        child.await;
-    }
-
-    for map in maps.lock().await.iter() {
+        let (path, freq) = child.await?;
         println!("{}: (: {}",
-                 map.0.display(),
-                 map.1.get(&'(').unwrap_or(&0));
+                 path.display(),
+                 freq.get(&'(').unwrap_or(&0));
     }
 
     Ok(())