rename zc_publisher_matching_listener_callback -> zc_publisher_matchi…

…ng_listener_declare; (#581)

added zc_publisher_get_matching_status;

docs/api.rst

@@ -572,6 +572,10 @@ Functions
 .. doxygenfunction:: zc_closure_matching_status_drop
 .. doxygenfunction:: zc_closure_matching_status_call
 
+.. doxygenfunction:: zc_publisher_get_matching_status
+.. doxygenfunction:: zc_publisher_matching_listener_declare
+.. doxygenfunction:: zc_publisher_matching_listener_undeclare
+
 Subscription
 ============
 

examples/z_pub.c

@@ -68,7 +68,7 @@ int main(int argc, char **argv) {
     if (add_matching_listener) {
         zc_owned_closure_matching_status_t callback;
         z_closure(&callback, matching_status_handler, NULL, NULL);
-        zc_publisher_matching_listener_callback(&listener, z_loan(pub), z_move(callback));
+        zc_publisher_matching_listener_declare(&listener, z_loan(pub), z_move(callback));
     }
 #else
     if (add_matching_listener) {

examples/z_pub_shm.c

@@ -79,7 +79,7 @@ int main(int argc, char **argv) {
     if (add_matching_listener) {
         zc_owned_closure_matching_status_t callback;
         z_closure(&callback, matching_status_handler, NULL, NULL);
-        zc_publisher_matching_listener_callback(&listener, z_loan(pub), z_move(callback));
+        zc_publisher_matching_listener_declare(&listener, z_loan(pub), z_move(callback));
     }
 #else
     if (add_matching_listener) {

include/zenoh_commons.h

@@ -4516,20 +4516,30 @@ ZENOHC_API z_result_t zc_liveliness_undeclare_token(zc_owned_liveliness_token_t
 #if defined(UNSTABLE)
 ZENOHC_API enum zc_locality_t zc_locality_default(void);
 #endif
+/**
+ * Gets publisher matching status - i.e. if there are any subscribers matching its key expression.
+ *
+ * @return 0 in case of success, negative error code otherwise (in this case matching_status is not updated).
+ */
+#if defined(UNSTABLE)
+ZENOHC_API
+z_result_t zc_publisher_get_matching_status(const struct z_loaned_publisher_t *this_,
+                                            struct zc_matching_status_t *matching_status);
+#endif
 /**
  * Constructs matching listener, registering a callback for notifying subscribers matching with a given publisher.
  *
  * @param this_: An unitilized memory location where matching listener will be constructed. The matching listener will be automatically dropped when publisher is dropped.
- * @publisher: A publisher to associate with matching listener.
- * @callback: A closure that will be called every time the matching status of the publisher changes (If last subscriber, disconnects or when the first subscriber connects).
+ * @param publisher: A publisher to associate with matching listener.
+ * @param callback: A closure that will be called every time the matching status of the publisher changes (If last subscriber, disconnects or when the first subscriber connects).
  *
  * @return 0 in case of success, negative error code otherwise.
  */
 #if defined(UNSTABLE)
 ZENOHC_API
-z_result_t zc_publisher_matching_listener_callback(zc_owned_matching_listener_t *this_,
-                                                   const struct z_loaned_publisher_t *publisher,
-                                                   struct zc_owned_closure_matching_status_t *callback);
+z_result_t zc_publisher_matching_listener_declare(zc_owned_matching_listener_t *this_,
+                                                  const struct z_loaned_publisher_t *publisher,
+                                                  struct zc_owned_closure_matching_status_t *callback);
 #endif
 /**
  * Undeclares the given matching listener, droping and invalidating it.

src/publisher.rs

@@ -315,13 +315,13 @@ pub struct zc_matching_status_t {
 /// Constructs matching listener, registering a callback for notifying subscribers matching with a given publisher.
 ///
 /// @param this_: An unitilized memory location where matching listener will be constructed. The matching listener will be automatically dropped when publisher is dropped.
-/// @publisher: A publisher to associate with matching listener.
-/// @callback: A closure that will be called every time the matching status of the publisher changes (If last subscriber, disconnects or when the first subscriber connects).
+/// @param publisher: A publisher to associate with matching listener.
+/// @param callback: A closure that will be called every time the matching status of the publisher changes (If last subscriber, disconnects or when the first subscriber connects).
 ///
 /// @return 0 in case of success, negative error code otherwise.
 #[no_mangle]
 #[allow(clippy::missing_safety_doc)]
-pub extern "C" fn zc_publisher_matching_listener_callback(
+pub extern "C" fn zc_publisher_matching_listener_declare(
     this: &mut MaybeUninit<zc_owned_matching_listener_t>,
     publisher: &'static z_loaned_publisher_t,
     callback: &mut zc_owned_closure_matching_status_t,
@@ -369,6 +369,30 @@ pub extern "C" fn zc_publisher_matching_listener_undeclare(
     result::Z_OK
 }
 
+#[cfg(feature = "unstable")]
+/// Gets publisher matching status - i.e. if there are any subscribers matching its key expression.
+///
+/// @return 0 in case of success, negative error code otherwise (in this case matching_status is not updated).
+#[no_mangle]
+#[allow(clippy::missing_safety_doc)]
+pub extern "C" fn zc_publisher_get_matching_status(
+    this: &'static z_loaned_publisher_t,
+    matching_status: &mut MaybeUninit<zc_matching_status_t>,
+) -> result::z_result_t {
+    match this.as_rust_type_ref().matching_status().wait() {
+        Ok(s) => {
+            matching_status.write(zc_matching_status_t {
+                matching: s.matching_subscribers(),
+            });
+            result::Z_OK
+        }
+        Err(e) => {
+            tracing::error!("{}", e);
+            result::Z_ENETWORK
+        }
+    }
+}
+
 /// Undeclares the given publisher, droping and invalidating it.
 ///
 /// @return 0 in case of success, negative error code otherwise.
@@ -378,7 +402,7 @@ pub extern "C" fn z_undeclare_publisher(this: &mut z_owned_publisher_t) -> resul
     if let Some(p) = this.as_rust_type_mut().take() {
         if let Err(e) = p.undeclare().wait() {
             tracing::error!("{}", e);
-            return result::Z_EGENERIC;
+            return result::Z_ENETWORK;
         }
     }
     result::Z_OK