perf: add batch variant of tr_torrentStat() (#8100)

* refactor: add [Torrent updateTorrents]

refactor: use updateTorrents in Controller

* refactor: add a batch variant of tr_torrentStat()

* refactor: use batch variant of tr_torrentStat() in GTK details dialog

* refactor: use batch variant of tr_torrentStat() in gtr_confirm_remove()

* refactor: use batch variant of tr_torrentStat() in updateTorrents

* refactor: add Session::find_torrents()

* refactor: remove the raw ptr variant of updateTorrents()

* refactor: remove tr_sessionLock()

* fixup! refactor: add [Torrent updateTorrents]

remove duplicate method declaration

* fix: readability-avoid-const-params-in-decls

* fix: iwyu in transmission.h

* chore: remove an #include that was added in a draft that did not get used

* refactor: use nullptr instead of NULL

macosx/Controller.mm

@@ -2367,20 +2367,16 @@ void onTorrentCompletenessChanged(tr_torrent* tor, tr_completeness status, bool
     BOOL anyCompleted = NO;
     BOOL anyActive = NO;
 
+    [Torrent updateTorrents:self.fTorrents];
+
+    for (Torrent* torrent in self.fTorrents)
     {
-        // avoid having to wait for the same lock multiple times in the same operation
-        auto const lock = tr_sessionLock(self.sessionHandle);
-        for (Torrent* torrent in self.fTorrents)
-        {
-            [torrent update];
+        //pull the upload and download speeds - most consistent by using current stats
+        dlRate += torrent.downloadRate;
+        ulRate += torrent.uploadRate;
 
-            //pull the upload and download speeds - most consistent by using current stats
-            dlRate += torrent.downloadRate;
-            ulRate += torrent.uploadRate;
-
-            anyCompleted |= torrent.finishedSeeding;
-            anyActive |= torrent.active && !torrent.stalled && !torrent.error;
-        }
+        anyCompleted |= torrent.finishedSeeding;
+        anyActive |= torrent.active && !torrent.stalled && !torrent.error;
     }
 
     PowerManager.shared.shouldPreventSleep = anyActive && [self.fDefaults boolForKey:@"SleepPrevent"];
@@ -3817,9 +3813,10 @@ void onTorrentCompletenessChanged(tr_torrent* tor, tr_completeness status, bool
             for (Torrent* torrent in self.fTorrents)
             {
                 torrent.queuePosition = i++;
-                [torrent update];
             }
 
+            [Torrent updateTorrents:self.fTorrents];
+
             //do the drag animation here so that the dragged torrents are the ones that are animated as moving, and not the torrents around them
             [self.fTableView beginUpdates];
 
@@ -5527,10 +5524,7 @@ void onTorrentCompletenessChanged(tr_torrent* tor, tr_completeness status, bool
 
 - (void)rpcUpdateQueue
 {
-    for (Torrent* torrent in self.fTorrents)
-    {
-        [torrent update];
-    }
+    [Torrent updateTorrents:self.fTorrents];
 
     NSSortDescriptor* descriptor = [NSSortDescriptor sortDescriptorWithKey:@"queuePosition" ascending:YES];
     NSArray* descriptors = @[ descriptor ];

macosx/Torrent.h

@@ -35,6 +35,10 @@ extern NSString* const kTorrentDidChangeGroupNotification;
 - (void)getAmountFinished:(float*)tab size:(int)size;
 @property(nonatomic) NSIndexSet* previousFinishedPieces;
 
+// Updates one or more torrents by refreshing their libtransmission stats.
+// Prefer using this batch method when updating many torrents at once.
++ (void)updateTorrents:(NSArray<Torrent*>*)torrents;
+
 - (void)update;
 
 - (void)startTransferIgnoringQueue:(BOOL)ignoreQueue;

macosx/Torrent.mm

@@ -242,19 +242,59 @@ bool trashDataFile(char const* filename, void* /*user_data*/, tr_error* error)
 
 - (void)update
 {
-    //get previous stalled value before update
-    BOOL const wasTransmitting = self.fStat != NULL && self.transmitting;
+    [Torrent updateTorrents:@[ self ]];
+}
 
-    self.fStat = tr_torrentStat(self.fHandle);
-
-    //make sure the "active" filter is updated when transmitting changes
-    if (wasTransmitting != self.transmitting)
++ (void)updateTorrents:(NSArray<Torrent*>*)torrents
+{
+    if (torrents == nil || torrents.count == 0)
     {
-        //posting asynchronously with coalescing to prevent stack overflow on lots of torrents changing state at the same time
-        [NSNotificationQueue.defaultQueue enqueueNotification:[NSNotification notificationWithName:@"UpdateTorrentsState" object:nil]
-                                                 postingStyle:NSPostASAP
-                                                 coalesceMask:NSNotificationCoalescingOnName
-                                                     forModes:nil];
+        return;
+    }
+
+    std::vector<Torrent*> torrent_objects;
+    torrent_objects.reserve(torrents.count);
+
+    std::vector<tr_torrent*> torrent_handles;
+    torrent_handles.reserve(torrents.count);
+
+    std::vector<BOOL> was_transmitting;
+    was_transmitting.reserve(torrents.count);
+
+    for (Torrent* torrent in torrents)
+    {
+        if (torrent == nil || torrent.fHandle == nullptr)
+        {
+            continue;
+        }
+
+        torrent_objects.emplace_back(torrent);
+        torrent_handles.emplace_back(torrent.fHandle);
+        was_transmitting.emplace_back(torrent.fStat != nullptr && torrent.transmitting);
+    }
+
+    if (torrent_handles.empty())
+    {
+        return;
+    }
+
+    auto const stats = tr_torrentStat(torrent_handles.data(), torrent_handles.size());
+
+    // Assign stats and post notifications.
+    for (size_t i = 0, n = torrent_objects.size(); i < n; ++i)
+    {
+        Torrent* const torrent = torrent_objects[i];
+        torrent.fStat = stats[i];
+
+        //make sure the "active" filter is updated when transmitting changes
+        if (was_transmitting[i] != torrent.transmitting)
+        {
+            //posting asynchronously with coalescing to prevent stack overflow on lots of torrents changing state at the same time
+            [NSNotificationQueue.defaultQueue enqueueNotification:[NSNotification notificationWithName:@"UpdateTorrentsState" object:nil]
+                                                     postingStyle:NSPostASAP
+                                                     coalesceMask:NSNotificationCoalescingOnName
+                                                         forModes:nil];
+        }
     }
 }