Add Transport-Neutral Serial Session Broker

src/serial_service.c

@@ -625,7 +625,9 @@ size_t serial_service_read(uint8_t *data, size_t size)
         return 0;
     }
 
-    xSemaphoreTake(s_state_mutex, portMAX_DELAY);
+    if (xSemaphoreTake(s_state_mutex, 0) != pdTRUE) {
+        return 0;
+    }
     size_t received = 0;
     if (s_running && !s_stop_requested) {
         received = xStreamBufferReceive(s_rx_stream, data, size, 0);
@@ -640,7 +642,9 @@ size_t serial_service_write(const uint8_t *data, size_t size)
         return 0;
     }
 
-    xSemaphoreTake(s_state_mutex, portMAX_DELAY);
+    if (xSemaphoreTake(s_state_mutex, 0) != pdTRUE) {
+        return 0;
+    }
     size_t accepted = 0;
     if (s_running && !s_stop_requested) {
         accepted = xStreamBufferSend(s_tx_stream, data, size, 0);
@@ -683,11 +687,13 @@ esp_err_t serial_service_set_session_active(bool active)
     }
 
     xSemaphoreTake(s_state_mutex, portMAX_DELAY);
-    s_session_active = active;
     esp_err_t result = ESP_OK;
     if (s_running && s_config.dtr_behavior == SERIAL_CONFIG_DTR_ON_CONNECT) {
         result = gpio_set_level(RS232_DTR_GPIO, active ? 0 : 1);
     }
+    if (result == ESP_OK) {
+        s_session_active = active;
+    }
     xSemaphoreGive(s_state_mutex);
     return result;
 }