Implemented queue_msg_waiting. (#1925)

* Implemented queue_msg_waiting.

* Fmt.

* Adjusted changelog.

* Fixed CI.

* Fixed pointer mutability.

esp-wifi/CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - Implement `embedded_io::{ReadReady, WriteReady}` traits for `WifiStack` (#1882)
+- Implement `queue_msg_waiting` on the os_adapter (#1925)
 
 ### Changed
 

esp-wifi/src/compat/common.rs

@@ -308,6 +308,14 @@ pub fn receive_queued(queue: *mut c_void, item: *mut c_void, block_time_tick: u3
         yield_task();
     }
 }
+pub fn number_of_messages_in_queue(queue: *const c_void) -> u32 {
+    trace!("queue_msg_waiting {:?}", queue);
+    if queue != unsafe { addr_of!(REAL_WIFI_QUEUE).cast() } {
+        warn!("queue_msg_waiting: Unknown queue.");
+        return 0;
+    }
+    critical_section::with(|_| unsafe { REAL_WIFI_QUEUE.len() as u32 })
+}
 
 /// Implementation of sleep() from newlib in esp-idf.
 /// components/newlib/time.c

esp-wifi/src/wifi/os_adapter.rs

@@ -20,6 +20,7 @@ use crate::{
             create_recursive_mutex,
             create_wifi_queue,
             lock_mutex,
+            number_of_messages_in_queue,
             receive_queued,
             send_queued,
             str_from_c,
@@ -530,8 +531,8 @@ pub unsafe extern "C" fn queue_recv(
 ///   Message number
 ///
 /// *************************************************************************
-pub unsafe extern "C" fn queue_msg_waiting(_queue: *mut crate::binary::c_types::c_void) -> u32 {
-    todo!("queue_msg_waiting")
+pub unsafe extern "C" fn queue_msg_waiting(queue: *mut crate::binary::c_types::c_void) -> u32 {
+    number_of_messages_in_queue(queue)
 }
 
 /// **************************************************************************