Move topic helper functions under MqttSchema

Signed-off-by: Didier Wenzek <[email protected]>

crates/core/tedge_api/src/mqtt_topics.rs

@@ -188,9 +188,37 @@ impl MqttSchema {
     pub fn error_topic(&self) -> Topic {
         Topic::new_unchecked(&format!("{0}/errors", self.root))
     }
-}
 
-impl MqttSchema {
+    /// Extract the entity identifier from a topic
+    ///
+    /// Note this function is not related to a specific topic root prefix
+    pub fn get_entity_id(topic: impl AsRef<str>) -> Option<String> {
+        match topic.as_ref().split('/').collect::<Vec<&str>>()[..] {
+            [_, t1, t2, t3, t4, ..] => Some(format!("{t1}/{t2}/{t3}/{t4}")),
+            _ => None,
+        }
+    }
+
+    /// Extract the operation name from a command topic
+    ///
+    /// Note this function is not related to a specific topic root prefix
+    pub fn get_operation_name(topic: impl AsRef<str>) -> Option<String> {
+        match topic.as_ref().split('/').collect::<Vec<&str>>()[..] {
+            [_, _, _, _, _, "cmd", op, ..] => Some(op.to_string()),
+            _ => None,
+        }
+    }
+
+    /// Extract the command instance identifier from a command topic
+    ///
+    /// Note this function is not related to a specific topic root prefix
+    pub fn get_command_id(topic: impl AsRef<str>) -> Option<String> {
+        match topic.as_ref().split('/').collect::<Vec<&str>>()[..] {
+            [_, _, _, _, _, "cmd", _, id] => Some(id.to_string()),
+            _ => None,
+        }
+    }
+
     fn parse(&self, topic: &str) -> Result<(EntityTopicId, Channel), EntityTopicError> {
         let (root, topic) = topic.split_once('/').ok_or(EntityTopicError::Root {
             expected: self.root.to_string(),

crates/core/tedge_api/src/workflow/state.rs

@@ -248,18 +248,15 @@ impl GenericCommandState {
     }
 
     fn target(&self) -> Option<String> {
-        match self.topic.name.split('/').collect::<Vec<&str>>()[..] {
-            [_, t1, t2, t3, t4, "cmd", _, _] => Some(format!("{t1}/{t2}/{t3}/{t4}")),
-            _ => None,
-        }
+        MqttSchema::get_entity_id(&self.topic)
     }
 
     pub fn operation(&self) -> Option<String> {
-        extract_command_identifier(&self.topic.name).map(|(operation, _)| operation)
+        MqttSchema::get_operation_name(&self.topic)
     }
 
     pub fn cmd_id(&self) -> Option<String> {
-        extract_command_identifier(&self.topic.name).map(|(_, cmd_id)| cmd_id)
+        MqttSchema::get_command_id(&self.topic)
     }
 
     pub fn is_init(&self) -> bool {
@@ -279,15 +276,6 @@ impl GenericCommandState {
     }
 }
 
-fn extract_command_identifier(topic: &str) -> Option<(String, String)> {
-    match topic.split('/').collect::<Vec<&str>>()[..] {
-        [_, _, _, _, _, "cmd", operation, cmd_id] => {
-            Some((operation.to_string(), cmd_id.to_string()))
-        }
-        _ => None,
-    }
-}
-
 impl GenericStateUpdate {
     pub fn empty_payload() -> Value {
         json!({})