From 746bdfe6b909cb21c088b0128ff7ec0dfb3067bb Mon Sep 17 00:00:00 2001
From: Todd Mortimer <todd@opennet.ca>
Date: Sat, 18 Apr 2020 19:48:25 -0400
Subject: [PATCH] Handle Dovecot's periodic IDLE notification messages ("OK
 Still here").

These messages show up at an interval controlled by Dovecot's
imap_idle_notify_interval setting, which defaults to 2 minutes.
These messages were causing the IDLE loop to exit prematurely
because it looks like a notification response from the server.
---
 src/extensions/idle.rs | 28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/src/extensions/idle.rs b/src/extensions/idle.rs
index e802d32..12aa514 100644
--- a/src/extensions/idle.rs
+++ b/src/extensions/idle.rs
@@ -93,16 +93,26 @@ impl<'a, T: Read + Write + 'a> Handle<'a, T> {
     /// This is necessary so that we can keep using the inner `Session` in `wait_keepalive`.
     fn wait_inner(&mut self) -> Result<()> {
         let mut v = Vec::new();
-        match self.session.readline(&mut v).map(|_| ()) {
-            Err(Error::Io(ref e))
-                if e.kind() == io::ErrorKind::TimedOut || e.kind() == io::ErrorKind::WouldBlock =>
-            {
-                // we need to refresh the IDLE connection
-                self.terminate()?;
-                self.init()?;
-                self.wait_inner()
+        loop {
+            match self.session.readline(&mut v).map(|_| ()) {
+                Err(Error::Io(ref e))
+                    if e.kind() == io::ErrorKind::TimedOut
+                        || e.kind() == io::ErrorKind::WouldBlock =>
+                {
+                    // we need to refresh the IDLE connection
+                    self.terminate()?;
+                    self.init()?;
+                    return self.wait_inner();
+                }
+                r => r,
+            }?;
+
+            // Handle Dovecot's imap_idle_notify_interval message
+            if v.eq_ignore_ascii_case(b"* OK Still here\r\n") {
+                v.clear();
+            } else {
+                break Ok(());
             }
-            r => r,
         }
     }