pass ByteBuffer pointer instead of struct

rust/xaynet-mobile/src/ffi/participant.rs

@@ -241,19 +241,24 @@ pub unsafe extern "C" fn xaynet_ffi_participant_save(
 /// assert(n_read == fsize);
 /// fclose(f);
 /// Participant *restored =
-///     xaynet_ffi_participant_restore("http://localhost:8081", buf);
+///     xaynet_ffi_participant_restore("http://localhost:8081", &buf);
 /// free(buf.data);
 /// ```
 #[no_mangle]
 pub unsafe extern "C" fn xaynet_ffi_participant_restore(
     url: FfiStr,
-    buffer: ByteBuffer,
+    buffer: *const ByteBuffer,
 ) -> *mut Participant {
     let url = match url.as_opt_str() {
         Some(url) => url,
         None => return ptr::null_mut(),
     };
 
+    let buffer: &ByteBuffer = match unsafe { buffer.as_ref() } {
+        Some(ptr) => ptr,
+        None => return ptr::null_mut(),
+    };
+
     if let Ok(participant) = Participant::restore(buffer.as_slice(), url) {
         Box::into_raw(Box::new(participant))
     } else {

rust/xaynet-mobile/tests/ffi_test.c

@@ -110,7 +110,7 @@ static char *test_participant_save_and_restore() {
 
   // restore the participant
   Participant *restored =
-      xaynet_ffi_participant_restore("http://localhost:8081", restore_buf);
+      xaynet_ffi_participant_restore("http://localhost:8081", &restore_buf);
   mu_assert("failed to restore participant", restored != NULL);
 
   // free memory

rust/xaynet-mobile/xaynet_ffi.h

@@ -487,11 +487,11 @@ const ByteBuffer *xaynet_ffi_participant_save(Participant *participant);
  * assert(n_read == fsize);
  * fclose(f);
  * Participant *restored =
- *     xaynet_ffi_participant_restore("http://localhost:8081", buf);
+ *     xaynet_ffi_participant_restore("http://localhost:8081", &buf);
  * free(buf.data);
  * ```
  */
-Participant *xaynet_ffi_participant_restore(FfiStr url, ByteBuffer buffer);
+Participant *xaynet_ffi_participant_restore(FfiStr url, const ByteBuffer *buffer);
 
 /**
  * Set the participant's model. Usually this should be called when the value returned