main+lib: Allow for interrupting image sending

This could probably be generalized to all messages, but apart from
this one, I think it would only make sense to also handle this for
cases where the user pastes 1.5GiB of plaintext into MsgConsole, but
then stdin is clogged up and there's no signals, so CTRL+A would wait
for its turn anyway..

Signed-off-by: Konrad Dybcio <konradybcio@kernel.org>

src/lib.rs

@@ -102,15 +102,23 @@ pub async fn console_print(buf: &[u8]) {
 }
 
 #[allow(clippy::explicit_write)]
-pub async fn send_image(write_sink: &mut Arc<Mutex<impl Write>>, buf: &[u8]) -> anyhow::Result<()> {
+pub async fn send_image(
+    write_sink: &mut Arc<Mutex<impl Write>>,
+    buf: &[u8],
+    quit: &Arc<Mutex<bool>>,
+) -> anyhow::Result<()> {
     let mut last_percent_done: usize = 0;
     let mut bytes_sent = 0;
 
     for chunk in buf.chunks(2048) {
         let percent_done = 100 * bytes_sent / buf.len();
 
+        if *quit.lock().await {
+            return Ok(());
+        }
+
         if percent_done != last_percent_done {
-            let s = format!(" Sending image: {}%\r", percent_done);
+            let s = format!("Sending image: {}%\r", percent_done);
             print!("{}", s.green());
             stdout().flush()?;
         }

src/main.rs

@@ -160,7 +160,7 @@ async fn main() -> anyhow::Result<()> {
                 Ok(Sk8brdMsgs::MsgPowerOff) => (),
                 Ok(Sk8brdMsgs::MsgFastbootPresent) => {
                     if !msgbuf.is_empty() && msgbuf[0] != 0 {
-                        send_image(&mut chan, &fastboot_image).await?
+                        send_image(&mut chan, &fastboot_image, &quit).await?
                     }
                 }
                 Ok(Sk8brdMsgs::MsgFastbootDownload) => (),
@@ -197,6 +197,6 @@ async fn main() -> anyhow::Result<()> {
     )
     .context("Couldn't disconnect cleanly")?;
 
-    println!("Goodbye");
+    println!("\nGoodbye");
     Ok(())
 }