refactor: [torrust#1543] Optimization: Don't load number of downloads from DB if not needed

Author: josecelano

packages/torrent-repository/src/swarms.rs

@@ -467,6 +467,10 @@ impl Swarms {
     pub fn is_empty(&self) -> bool {
         self.swarms.is_empty()
     }
+
+    pub fn contains(&self, key: &InfoHash) -> bool {
+        self.swarms.contains_key(key)
+    }
 }
 
 #[derive(thiserror::Error, Debug, Clone)]

packages/tracker-core/src/announce_handler.rs

@@ -96,9 +96,10 @@ use std::sync::Arc;
 use bittorrent_primitives::info_hash::InfoHash;
 use torrust_tracker_configuration::{Core, TORRENT_PEERS_LIMIT};
 use torrust_tracker_primitives::core::AnnounceData;
-use torrust_tracker_primitives::peer;
+use torrust_tracker_primitives::{peer, NumberOfDownloads};
 
 use super::torrent::repository::in_memory::InMemoryTorrentRepository;
+use crate::databases;
 use crate::error::AnnounceError;
 use crate::statistics::persisted::downloads::DatabaseDownloadsMetricRepository;
 use crate::whitelist::authorization::WhitelistAuthorization;
@@ -163,21 +164,28 @@ impl AnnounceHandler {
     ) -> Result<AnnounceData, AnnounceError> {
         self.whitelist_authorization.authorize(info_hash).await?;
 
-        let opt_persistent_torrent = if self.config.tracker_policy.persistent_torrent_completed_stat {
-            self.db_downloads_metric_repository.load_torrent_downloads(info_hash)?
-        } else {
-            None
-        };
-
         peer.change_ip(&assign_ip_address_to_peer(remote_client_ip, self.config.net.external_ip));
 
         self.in_memory_torrent_repository
-            .handle_announcement(info_hash, peer, opt_persistent_torrent)
+            .handle_announcement(info_hash, peer, self.load_downloads_metric_if_needed(info_hash)?)
             .await;
 
         Ok(self.build_announce_data(info_hash, peer, peers_wanted).await)
     }
 
+    /// Loads the number of downloads for a torrent if needed.
+    fn load_downloads_metric_if_needed(
+        &self,
+        info_hash: &InfoHash,
+    ) -> Result<Option<NumberOfDownloads>, databases::error::Error> {
+        if self.config.tracker_policy.persistent_torrent_completed_stat && !self.in_memory_torrent_repository.contains(info_hash)
+        {
+            Ok(self.db_downloads_metric_repository.load_torrent_downloads(info_hash)?)
+        } else {
+            Ok(None)
+        }
+    }
+
     /// Builds the announce data for the peer making the request.
     async fn build_announce_data(&self, info_hash: &InfoHash, peer: &peer::Peer, peers_wanted: &PeersWanted) -> AnnounceData {
         let peers = self

packages/tracker-core/src/torrent/repository/in_memory.rs

@@ -267,4 +267,10 @@ impl InMemoryTorrentRepository {
     pub fn import_persistent(&self, persistent_torrents: &NumberOfDownloadsBTreeMap) {
         self.swarms.import_persistent(persistent_torrents);
     }
+
+    /// Checks if the repository contains a torrent entry for the given infohash.
+    #[must_use]
+    pub fn contains(&self, info_hash: &InfoHash) -> bool {
+        self.swarms.contains(info_hash)
+    }
 }