From 2a4e9ae4bc6e8c540688ae0d3da32ea859f68b8a Mon Sep 17 00:00:00 2001
From: Florian Stecker <mail@florianstecker.de>
Date: Thu, 13 Jul 2023 22:04:27 +0200
Subject: [PATCH] improve handling of some rare errors

---
 src/lib.rs | 78 ++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 50 insertions(+), 28 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index c353638..332299f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -56,6 +56,7 @@ struct Status {
 
 const CONNECTION_LOST_ERRORS: &[ErrorKind] = &[
 	ErrorKind::Interrupted,
+	ErrorKind::UnexpectedEOF,   // server closes TLS connection without close_notify
 	ErrorKind::WouldBlock,      // when a read times out
 ];
 
@@ -157,7 +158,8 @@ pub fn run() -> AResult<()> {
 					connection_status.lock().unwrap().connected = false;
 
 					time_to_reconnect = 1;
-					println!("Connection lost, reconnecting in {time_to_reconnect} seconds");
+					let error_kind = io_err.kind();
+					println!("Connection lost ({error_kind}), reconnecting in {time_to_reconnect} seconds");
 					thread::sleep(Duration::from_secs(time_to_reconnect));
 
 					continue;
@@ -170,7 +172,9 @@ pub fn run() -> AResult<()> {
 					if cli.verbose > 0 {
 						println!("Error: {:?}", err);
 					}
-					println!("Cannot connect currently, retrying in {time_to_reconnect} seconds");
+
+					let error_kind = io_err.kind();
+					println!("Cannot connect currently ({error_kind}), retrying in {time_to_reconnect} seconds");
 
 					thread::sleep(Duration::from_secs(time_to_reconnect));
 
@@ -235,11 +239,20 @@ pub fn connect_and_idle<F: Fn(), G: Fn()>(cli: &Cli, connected_callback: F, mail
 		} else if tls_client.wants_read() {
 			let _i = tls_client.read_tls(&mut socket)?;
 
-			if tls_client.process_new_packets()?.plaintext_bytes_to_read() == 0 {
+			let bytes_to_read = tls_client.process_new_packets()?.plaintext_bytes_to_read();
+			if bytes_to_read == 0 {
 				continue;
 			}
 
-			let len = tls_client.reader().read(&mut buffer)?;
+			println!("Bytes to read: {bytes_to_read}");
+
+			let mut len = tls_client.reader().read(&mut buffer)?;
+
+			while len == buffer.len() {
+				println!("Buffer full, read again");
+				len = tls_client.reader().read(&mut buffer)?;
+			}
+
 
 			let responses = buffer[0..len]
 				.split(|&x|x == b'\r' || x == b'\n')
@@ -257,35 +270,44 @@ pub fn connect_and_idle<F: Fn(), G: Fn()>(cli: &Cli, connected_callback: F, mail
 				}
 
 				match state {
-					ImapState::Unauthenticated => if response.starts_with(b"* OK") {
-						let request = format!("A001 login {} {}\r\n", cli.username, cli.password);
-						tls_client.writer().write(request.as_bytes())?;
-						state = ImapState::Authenticated;
-					},
-					ImapState::Authenticated => if response.starts_with(b"A001 OK") {
-						tls_client.writer().write(b"A002 select inbox\r\n")?;
-						state = ImapState::Inbox;
-					} else if response.starts_with(b"A001") {
-						bail!("The server rejected authentication");
-					},
-					ImapState::Inbox => if response.starts_with(b"A002 OK") {
-						tls_client.writer().write(b"A003 idle\r\n")?;
-						state = ImapState::Idling;
-						connected_callback();
-						// notify timer thread that we're live
-					} else if response.starts_with(b"A002") {
-						bail!("Selecting inbox failed");
-					},
-					ImapState::Idling => if response.starts_with(b"+ idling") {
-						println!("Connected and idling ...");
-					} else if response.starts_with(b"*") && response.ends_with(b"EXISTS") {
-						mail_callback();
-					}
+					ImapState::Unauthenticated =>
+						if response.starts_with(b"* OK") {
+							let request = format!("A001 login {} {}\r\n", cli.username, cli.password);
+							tls_client.writer().write(request.as_bytes())?;
+							state = ImapState::Authenticated;
+						},
+					ImapState::Authenticated =>
+						if response.starts_with(b"A001 OK") {
+							tls_client.writer().write(b"A002 select inbox\r\n")?;
+							state = ImapState::Authenticated;
+						} else if response.starts_with(b"A002 OK") {
+							tls_client.writer().write(b"A003 fetch 1:* all\r\n")?;
+							state = ImapState::Inbox;
+						} else if response.starts_with(b"A001") || response.starts_with(b"A002") {
+							bail!("The server rejected authentication");
+						},
+					ImapState::Inbox =>
+						if response.starts_with(b"A003 OK") {
+							tls_client.writer().write(b"A004 idle\r\n")?;
+							state = ImapState::Idling;
+							connected_callback(); // notify timer thread that we're live
+						} else if response.starts_with(b"A002") {
+							bail!("Selecting inbox failed");
+						},
+					ImapState::Idling =>
+						if response.starts_with(b"+ idling") {
+							println!("Connected and idling ...");
+						} else if response.starts_with(b"*") && response.ends_with(b"EXISTS") {
+							mail_callback();
+						}
 				}
 			}
 		} else {
 			// if wants_read() and wants_write() are both false, this usually means the connection was closed
 			// so just return "Interrupted" and reconnect after a few seconds
+			if cli.verbose > 0 {
+				println!("wants_read() and wants_write() are both false");
+			}
 			return Err(io::Error::new(ErrorKind::Interrupted, "Connection was closed by server").into());
 		}
 	}