Make the publish call return a result

Potential solution for eclipse-paho#101

Signed-off-by: Sander van Harmelen <sander@vanharmelen.nl>

src/async_client.rs

@@ -633,7 +633,7 @@ impl AsyncClient {
     ///
     /// * `msg` The message to publish.
     ///
-    pub fn publish(&self, msg: Message) -> DeliveryToken {
+    pub fn publish(&self, msg: Message) -> Result<DeliveryToken> {
         debug!("Publish: {:?}", msg);
 
         let ver = self.mqtt_version();
@@ -648,13 +648,11 @@ impl AsyncClient {
         };
 
         if rc != 0 {
-            let _ = unsafe { Token::from_raw(rsp_opts.copts.context) };
-            let msg: Message = tok.into();
-            DeliveryToken::from_error(msg, rc)
-        }
-        else {
+            warn!("Publish result: {}", rc);
+            Err(rc.into())
+        } else {
             tok.set_msgid(rsp_opts.copts.token as i16);
-            tok
+            Ok(tok)
         }
     }
 

src/client.rs

@@ -137,7 +137,7 @@ impl Client {
 
     /// Publishes a message to an MQTT broker
     pub fn publish(&self, msg: Message) -> Result<()> {
-        self.cli.publish(msg).wait_for(self.timeout)
+        self.cli.publish(msg)?.wait_for(self.timeout)
     }
 
     /// Subscribes to a single topic.

src/topic.rs

@@ -23,6 +23,7 @@
 
 use crate::{
     async_client::AsyncClient,
+    errors::Result,
     token::{
         Token,
         DeliveryToken,
@@ -107,8 +108,9 @@ impl<'a> Topic<'a>
     ///
     /// `payload` The payload of the message
     ///
-    pub fn publish<V>(&self, payload: V) -> DeliveryToken
-        where V: Into<Vec<u8>>
+    pub fn publish<V>(&self, payload: V) -> Result<DeliveryToken>
+    where
+        V: Into<Vec<u8>>,
     {
         // OPTIMIZE: This could be more efficient.
         let msg = Message::new(self.topic.clone(), payload, self.qos);