From ec0882609c496933d53d40d15ea6282013ba043b Mon Sep 17 00:00:00 2001
From: Andrey <amborodin@acm.org>
Date: Tue, 21 Jan 2020 12:01:55 +0500
Subject: [PATCH] Move try-read logic to relay_start

Previously we tried to avoid attaching to server connection
by read-testing client before attach. This does not work well
when client wants to disconnect: we read from client twice,
and it happens after Term(X,88) message from client.
To avoid this problem we move read-tesing to start of relay.
---
 sources/relay.h | 37 +++++++++++++++++++++++--------------
 1 file changed, 23 insertions(+), 14 deletions(-)

diff --git a/sources/relay.h b/sources/relay.h
index 868df36a..a437a9b5 100644
--- a/sources/relay.h
+++ b/sources/relay.h
@@ -30,6 +30,8 @@ struct od_relay
 	void                 *on_read_arg;
 };
 
+static inline od_status_t od_relay_read(od_relay_t *relay);
+
 static inline void
 od_relay_init(od_relay_t *relay, od_io_t *io)
 {
@@ -58,6 +60,14 @@ od_relay_free(od_relay_t *relay)
 		machine_iov_free(relay->iov);
 }
 
+static inline bool
+od_relay_data_pending(od_relay_t *relay)
+{
+	char *current = od_readahead_pos_read(&relay->src->readahead);
+	char *end     = od_readahead_pos(&relay->src->readahead);
+	return current < end;
+}
+
 static inline od_status_t
 od_relay_start(od_relay_t *relay,
                machine_cond_t       *base,
@@ -89,6 +99,19 @@ od_relay_start(od_relay_t *relay,
 	if (rc == -1)
 		return relay->error_read;
 
+	// If there is no new data from client we must reset read condition
+	// to avoid attaching to a new server connection
+
+	if (machine_cond_try(relay->src->on_read)) {
+		rc = od_relay_read(relay);
+		if (rc != OD_OK)
+			return rc;
+		if (od_relay_data_pending(relay)) {
+			// Seems like some data arrived
+			machine_cond_signal(relay->src->on_read);
+		}
+	}
+
 	return OD_OK;
 }
 
@@ -246,14 +269,6 @@ od_relay_process(od_relay_t *relay, int *progress, char *data, int size)
 	return OD_OK;
 }
 
-static inline bool
-od_relay_data_pending(od_relay_t *relay)
-{
-	char *current = od_readahead_pos_read(&relay->src->readahead);
-	char *end     = od_readahead_pos(&relay->src->readahead);
-	return current < end;
-}
-
 static inline od_status_t
 od_relay_pipeline(od_relay_t *relay)
 {
@@ -334,12 +349,6 @@ od_relay_step(od_relay_t *relay)
 	if (machine_cond_try(relay->src->on_read))
 	{
 		if (relay->dst == NULL) {
-			rc = od_relay_read(relay);
-			if (rc != OD_OK)
-				return rc;
-			if (!od_relay_data_pending(relay))
-				return OD_OK;
-
 			/* signal to retry on read logic */
 			machine_cond_signal(relay->src->on_read);
 			return OD_ATTACH;