Convert more functions to "async fn"

podcasts-data/src/feed.rs

@@ -21,7 +21,6 @@
 #![allow(clippy::unit_arg)]
 //! Index Feeds.
 
-use futures::future::*;
 use futures::prelude::*;
 use futures::stream;
 use rss;
@@ -54,7 +53,7 @@ impl Feed {
         NewShow::new(&self.channel, self.source_id)
     }
 
-    fn index_channel_items(self, pd: Show) -> impl Future<Output = Result<(), DataError>> + Send {
+    async fn index_channel_items(self, pd: Show) -> Result<(), DataError> {
         let stream = stream::iter(self.channel.into_items());
         // Parse the episodes
         let episodes = stream.filter_map(move |item| {
@@ -67,9 +66,9 @@ impl Feed {
             }
         });
         // Filter errors, Index updatable episodes, return insertables.
-        filter_episodes(episodes)
-            // Batch index insertable episodes.
-            .and_then(|eps| ok(batch_insert_episodes(&eps)))
+        let insertable_episodes = filter_episodes(episodes).await?;
+        batch_insert_episodes(&insertable_episodes);
+        Ok(())
     }
 }
 
@@ -94,32 +93,31 @@ fn determine_ep_state(
     }
 }
 
-fn filter_episodes<'a, S>(
-    stream: S,
-) -> impl Future<Output = Result<Vec<NewEpisode>, DataError>> + Send + 'a
+async fn filter_episodes<'a, S>(stream: S) -> Result<Vec<NewEpisode>, DataError>
 where
-    S: Stream<Item = Result<IndexState<NewEpisode>, DataError>> + Send + 'a,
+    S: Stream<Item = Result<IndexState<NewEpisode>, DataError>>,
 {
     stream
         .try_filter_map(|state| {
-            async move {
-                match state {
-                    IndexState::NotChanged => Ok(None),
+            async {
+                let result = match state {
+                    IndexState::NotChanged => None,
                     // Update individual rows, and filter them
                     IndexState::Update((ref ep, rowid)) => {
                         ep.update(rowid)
                             .map_err(|err| error!("{}", err))
                             .map_err(|_| error!("Failed to index episode: {:?}.", ep.title()))
                             .ok();
-
-                        Ok(None)
+                        None
                     }
-                    IndexState::Index(s) => Ok(Some(s)),
-                }
+                    IndexState::Index(s) => Some(s),
+                };
+                Ok(result)
             }
         })
         // only Index is left, collect them for batch index
         .try_collect()
+        .await
 }
 
 fn batch_insert_episodes(episodes: &[NewEpisode]) {