static cell usage

final/src/mqtt/client.rs

@@ -6,21 +6,28 @@ use rust_mqtt::client::client::MqttClient;
 use rust_mqtt::client::client_config::{ClientConfig, MqttVersion};
 use rust_mqtt::packet::v5::publish_packet::QualityOfService;
 use rust_mqtt::utils::rng_generator::CountingRng;
+use static_cell::ConstStaticCell;
+
+// TCP socket buffers (for embassy-net TcpSocket)
+static TCP_RX_BUFFER: ConstStaticCell<[u8; 2048]> = ConstStaticCell::new([0; 2048]);
+static TCP_TX_BUFFER: ConstStaticCell<[u8; 2048]> = ConstStaticCell::new([0; 2048]);
+
+// MQTT client buffers (separate from the TcpSocket’s buffers)
+static MQTT_TX_BUF: ConstStaticCell<[u8; 1024]> = ConstStaticCell::new([0; 1024]);
+static MQTT_RX_BUF: ConstStaticCell<[u8; 1024]> = ConstStaticCell::new([0; 1024]);
 
 #[embassy_executor::task]
 pub async fn mqtt_task(stack: Stack<'static>) {
     info!("MQTT task starting...");
 
-    // TCP socket buffers (for embassy-net TcpSocket)
-    static mut TCP_RX_BUFFER: [u8; 2048] = [0; 2048];
-    static mut TCP_TX_BUFFER: [u8; 2048] = [0; 2048];
+    // Safely take buffers (only allowed once)
+    let tcp_rx = TCP_RX_BUFFER.take();
+    let tcp_tx = TCP_TX_BUFFER.take();
 
-    // pass Stack by value
-    let mut socket =
-        TcpSocket::new(stack, unsafe { &mut TCP_RX_BUFFER }, unsafe { &mut TCP_TX_BUFFER });
+    // Pass Stack by value to embassy-net TcpSocket
+    let mut socket = TcpSocket::new(stack, tcp_rx, tcp_tx);
 
-    // Adjust broker IP/port as needed
-    // TODO
+    // TODO broker details
     let broker_ip = Ipv4Address::new(192, 168, 1, 100);
     let broker_port = 1883;
 
@@ -32,32 +39,27 @@ pub async fn mqtt_task(stack: Stack<'static>) {
         }
     }
 
-    // MQTT client buffers (separate from the TcpSocket's buffers)
-    static mut MQTT_TX_BUF: [u8; 1024] = [0; 1024];
-    static mut MQTT_RX_BUF: [u8; 1024] = [0; 1024];
+    // Safely take MQTT buffers
+    let mqtt_tx = MQTT_TX_BUF.take();
+    let mqtt_rx = MQTT_RX_BUF.take();
 
-    // rust-mqtt 0.3.0 RNG
+    let mqtt_tx_len = mqtt_tx.len();
+    let mqtt_rx_len = mqtt_rx.len();
+
+    // RNG
     let rng = CountingRng(0);
 
-    // Build client config
+    // Build config
     let mut cfg: ClientConfig<'static, 8, _> = ClientConfig::new(MqttVersion::MQTTv5, rng);
     cfg.keep_alive = 60;
     cfg.add_client_id("esp32-client");
-    // Optional:
     // cfg.add_username("user");
     // cfg.add_password("pass");
 
-    // Create client
-    let mut client: MqttClient<'static, _, 8, _> = MqttClient::new(
-        socket,
-        unsafe { &mut MQTT_TX_BUF },
-        unsafe { MQTT_TX_BUF.len() },
-        unsafe { &mut MQTT_RX_BUF },
-        unsafe { MQTT_RX_BUF.len() },
-        cfg,
-    );
+    // Build MQTT client
+    let mut client = MqttClient::new(socket, mqtt_tx, mqtt_tx_len, mqtt_rx, mqtt_rx_len, cfg);    
 
-    // CONNECT
+    // Connect
     match client.connect_to_broker().await {
         Ok(_) => info!("MQTT CONNACK received"),
         Err(reason) => {
@@ -66,7 +68,7 @@ pub async fn mqtt_task(stack: Stack<'static>) {
         }
     }
 
-    // Publish a message (QoS1)
+    // Publish simple message
     match client
         .send_message(
             "esp32/topic",
@@ -80,7 +82,7 @@ pub async fn mqtt_task(stack: Stack<'static>) {
         Err(reason) => info!("MQTT publish failed: {:?}", reason),
     }
 
-    // Keep the session alive; send PING and await PINGRESP every 30s
+    // Keep alive
     loop {
         if let Err(reason) = client.send_ping().await {
             info!("MQTT ping failed: {:?}", reason);