Implement function to get the amount of buffered messages (incl. QOS 0)

include/mqtt/async_client.h

@@ -499,6 +499,11 @@ class async_client : public virtual iasync_client
      * @return delivery_token[]
      */
     std::vector<delivery_token_ptr> get_pending_delivery_tokens() const override;
+    /**
+     * Returns the current number of buffered (publish) messages for this client.
+     * @return number of buffered messages
+     */
+    virtual int get_buffered_messages_num() const override;
     /**
      * Returns the client ID used by this client.
      * @return The client ID used by this client.

include/mqtt/iasync_client.h

@@ -181,6 +181,11 @@ class iasync_client
      * @return delivery_token[]
      */
     virtual std::vector<delivery_token_ptr> get_pending_delivery_tokens() const = 0;
+    /**
+     * Returns the current number of buffered (publish) messages for this client.
+     * @return number of buffered messages
+     */
+    virtual int get_buffered_messages_num() const = 0;
     /**
      * Returns the client ID used by this client.
      * @return string

src/async_client.cpp

@@ -31,6 +31,12 @@
 #include "mqtt/response_options.h"
 #include "mqtt/token.h"
 
+// Include MQTTAsyncUtils, but need a workaround for the error
+// ""redeclaration of C++ built-in type ‘bool’" inside this header"
+#define bool c_bool  
+#include <MQTTAsyncUtils.h>
+#undef bool
+
 #define UNUSED(x) (void)(x)
 
 namespace mqtt {
@@ -559,8 +565,22 @@ std::vector<delivery_token_ptr> async_client::get_pending_delivery_tokens() cons
         }
     }
     return toks;
+
+}
+
+int async_client::get_buffered_messages_num() const
+{
+    // Gets number of all buffered messages (QOS0-2)
+    // I'd like to have used MQTTAsync_getNoBufferedMessages() from MQTTAsyncUtils.h
+    // directly, but I haven't gotten it to compile correctly
+    // I hope the C++ lock_ also serves the same functionality as the C MQTTAsync mutex
+
+    guard g(lock_);
+    return ((MQTTAsyncs*)cli_)->noBufferedMessages;
 }
 
+
+
 // --------------------------------------------------------------------------
 // Publish
 

test/unit/mock_async_client.h

@@ -109,6 +109,11 @@ class mock_async_client : public virtual mqtt::iasync_client
         return std::vector<mqtt::delivery_token_ptr>{};
     };
 
+    int get_buffered_messages_num() const override
+    {
+        return 0;
+    }
+
     std::string get_client_id() const override { return std::string{}; };
 
     std::string get_server_uri() const override { return std::string{}; };