refactor(favorite): stop using async fs operations, simplify and optimize

src/app.rs

@@ -101,7 +101,7 @@ impl App {
             ..Default::default()
         };
 
-        let favorite_devices = read_favorite_devices_from_disk().await.unwrap_or_default();
+        let favorite_devices = read_favorite_devices_from_disk().unwrap_or_default();
 
         let handle = session.register_agent(agent).await?;
         let controllers: Vec<Controller> =

src/favorite.rs

@@ -1,29 +1,29 @@
 use crate::app::AppResult;
 use anyhow::Context;
 use bluer::Address;
-use std::str::FromStr;
-use tokio::io::{AsyncBufReadExt, BufReader};
+use std::{
+    fs::File,
+    io::{BufRead, BufReader},
+    str::FromStr,
+};
 
-pub async fn read_favorite_devices_from_disk() -> AppResult<Vec<Address>> {
+pub fn read_favorite_devices_from_disk() -> AppResult<Vec<Address>> {
     let data_dir = dirs::data_dir()
         .context("unable to find data_dir")?
         .join("bluetui");
 
-    let file = tokio::fs::File::open(data_dir.join("favorites.txt"))
-        .await
-        .context("unable to open favorites file")?;
+    let file =
+        File::open(data_dir.join("favorites.txt")).context("unable to open favorites file")?;
 
-    let mut lines = BufReader::new(file).lines();
+    let lines = BufReader::new(file).lines();
 
-    let mut favorite_devices = Vec::new();
-
-    while let Some(line) = lines.next_line().await? {
-        if let Ok(addr) = Address::from_str(&line) {
-            favorite_devices.push(addr);
-        }
-    }
-
-    Ok(favorite_devices)
+    lines
+        .map(|line| {
+            let line = line?;
+            let addr = Address::from_str(&line)?;
+            Ok(addr)
+        })
+        .collect()
 }
 
 pub fn save_favorite_devices_to_disk(favorite_devices: &[Address]) -> AppResult<()> {
@@ -31,17 +31,19 @@ pub fn save_favorite_devices_to_disk(favorite_devices: &[Address]) -> AppResult<
         .context("unable to find data_dir")?
         .join("bluetui");
 
+    if !data_dir.exists() {
+        std::fs::create_dir_all(&data_dir)
+            .context("unable to create parent dir(s) to favorites file")?;
+    }
+
     let file_path = data_dir.join("favorites.txt");
 
-    let contents = favorite_devices
-        .iter()
-        .map(Address::to_string)
-        .collect::<Vec<_>>()
-        .join("\n");
+    let mut contents =
+        String::with_capacity(favorite_devices.len() * (Address::any().to_string() + "\n").len());
 
-    if !data_dir.exists() {
-        std::fs::create_dir_all(data_dir)
-            .context("unable to create parent dir(s) to favorites file")?;
+    for device in favorite_devices {
+        contents.push_str(&device.to_string());
+        contents.push('\n');
     }
 
     std::fs::write(file_path, contents).context("error writing favorites file")?;