fix race condition where a transferring leg could be hungup on by the bridge…

fix race condition where a transferring leg could be hungup on by the bridge partner from the previous bridge because of hangup held leg detection.  The leg which was hungup when held doesn't realize the other leg has already moved on from the bridge because it was transferred and is already on its way to connect to the new destination

src/switch_ivr_bridge.c

@@ -199,6 +199,8 @@ struct switch_ivr_bridge_data {
 	switch_input_callback_function_t input_callback;
 	void *session_data;
 	int clean_exit;
+	int done;
+	struct switch_ivr_bridge_data *other_leg_data;
 };
 typedef struct switch_ivr_bridge_data switch_ivr_bridge_data_t;
 
@@ -358,6 +360,9 @@ static void *audio_bridge_thread(switch_thread_t *thread, void *obj)
 		}
 
 		if (!switch_channel_ready(chan_a)) {
+			if (switch_channel_up(chan_a)) {
+				data->clean_exit = 1;
+			}
 			goto end_of_bridge_loop;
 		}
 
@@ -648,7 +653,7 @@ static void *audio_bridge_thread(switch_thread_t *thread, void *obj)
 	switch_channel_clear_flag(chan_a, CF_BRIDGED);
 	
 	if (switch_channel_test_flag(chan_a, CF_LEG_HOLDING) || switch_channel_test_flag(chan_a, CF_HANGUP_HELD)) {
-		if (switch_channel_ready(chan_b) && switch_channel_get_state(chan_b) != CS_PARK) {
+		if (switch_channel_ready(chan_b) && switch_channel_get_state(chan_b) != CS_PARK && !data->other_leg_data->clean_exit) {
 			const char *ext = switch_channel_get_variable(chan_a, "hold_hangup_xfer_exten");
 			
 			switch_channel_stop_broadcast(chan_b);
@@ -675,6 +680,7 @@ static void *audio_bridge_thread(switch_thread_t *thread, void *obj)
 
 
 	switch_core_session_kill_channel(session_b, SWITCH_SIG_BREAK);
+	data->done = 1;
 	switch_core_session_rwunlock(session_b);
 	return NULL;
 }
@@ -1313,6 +1319,7 @@ SWITCH_DECLARE(switch_status_t) switch_ivr_multi_threaded_bridge(switch_core_ses
 	b_leg->input_callback = input_callback;
 	b_leg->session_data = peer_session_data;
 	b_leg->clean_exit = 0;
+	b_leg->other_leg_data = a_leg;
 
 	a_leg->session = session;
 	switch_copy_string(a_leg->b_uuid, switch_core_session_get_uuid(peer_session), sizeof(a_leg->b_uuid));
@@ -1320,6 +1327,7 @@ SWITCH_DECLARE(switch_status_t) switch_ivr_multi_threaded_bridge(switch_core_ses
 	a_leg->input_callback = input_callback;
 	a_leg->session_data = session_data;
 	a_leg->clean_exit = 0;
+	a_leg->other_leg_data = b_leg;
 
 	switch_channel_add_state_handler(peer_channel, &audio_bridge_peer_state_handlers);