cache: improved code pathways for cache

Viewers are now more aware of each other and can pause each others' cache tasks
when one of them plays, as well as wait for other viewers' cache tasks to
finish before starting their own.

app/core.cpp

@@ -1136,9 +1136,16 @@ void Core::CacheActiveSequence(bool in_out_only)
                                     in_out_only);
 
     // Stop any current auto-cache tasks
-    ViewerWidget::StopAllBackgroundCacheTasks();
+    ViewerWidget::StopAllBackgroundCacheTasks(true);
+    ViewerWidget::SetBackgroundCacheTask(task);
 
     TaskDialog* dialog = new TaskDialog(task, tr("Caching Sequence"), main_window_);
+
+    connect(dialog,
+            &TaskDialog::TaskSucceeded,
+            this,
+            [] { ViewerWidget::SetBackgroundCacheTask(nullptr); });
+
     dialog->open();
   }
 }

app/widget/viewer/viewer.cpp

@@ -46,6 +46,8 @@ const int kMaxPreQueueSize = 16;
 
 CacheTask* ViewerWidget::cache_background_task_ = nullptr;
 
+int ViewerWidget::busy_viewers_ = 0;
+
 ViewerWidget::ViewerWidget(QWidget *parent) :
   TimeBasedWidget(false, true, parent),
   playback_speed_(0),
@@ -55,7 +57,9 @@ ViewerWidget::ViewerWidget(QWidget *parent) :
   override_color_manager_(nullptr),
   time_changed_from_timer_(false),
   playback_is_audio_only_(false),
-  prequeuing_(false)
+  prequeuing_(false),
+  busy_(false),
+  our_cache_background_task_(nullptr)
 {
   // Set up main layout
   QVBoxLayout* layout = new QVBoxLayout(this);
@@ -237,7 +241,7 @@ void ViewerWidget::DisconnectNodeInternal(ViewerOutput *n)
   waveform_view_->SetViewer(nullptr);
   waveform_view_->ConnectTimelinePoints(nullptr);
 
-  StopAllBackgroundCacheTasks();
+  StopAllBackgroundCacheTasks(true);
   cache_background_task_ = nullptr;
   cache_wait_timer_.stop();
 }
@@ -360,9 +364,16 @@ void ViewerWidget::SetGizmos(Node *node)
   display_widget_->SetGizmos(node);
 }
 
-void ViewerWidget::StopAllBackgroundCacheTasks()
+void ViewerWidget::StopAllBackgroundCacheTasks(bool wait)
 {
-  TaskManager::instance()->CancelTaskAndWait(cache_background_task_);
+  if (cache_background_task_) {
+    if (wait) {
+      TaskManager::instance()->CancelTaskAndWait(cache_background_task_);
+    } else {
+      cache_background_task_->Cancel();
+    }
+    cache_background_task_ = nullptr;
+  }
 }
 
 void ViewerWidget::SetBackgroundCacheTask(CacheTask *t)
@@ -481,7 +492,36 @@ void ViewerWidget::PlayInternal(int speed, bool in_to_out_only)
     FillPlaybackQueue();
   }
 
-  StopBackgroundCache();
+  if (!busy_) {
+    busy_ = true;
+    busy_viewers_++;
+  }
+
+  StopAllBackgroundCacheTasks(false);
+  cache_wait_timer_.stop();
+}
+
+void ViewerWidget::PauseInternal()
+{
+  if (IsPlaying()) {
+    AudioManager::instance()->StopOutput();
+    playback_speed_ = 0;
+    controls_->ShowPlayButton();
+
+    if (playback_is_audio_only_) {
+      disconnect(AudioManager::instance(), &AudioManager::OutputNotified, this, &ViewerWidget::PlaybackTimerUpdate);
+    } else {
+      disconnect(display_widget_, &ViewerDisplayWidget::frameSwapped, this, &ViewerWidget::PlaybackTimerUpdate);
+    }
+
+    foreach (ViewerWindow* window, windows_) {
+      window->Pause();
+    }
+
+    playback_queue_.clear();
+  }
+
+  prequeuing_ = false;
 }
 
 void ViewerWidget::PushScrubbedAudio()
@@ -657,15 +697,6 @@ AudioRenderingParams ViewerWidget::GenerateAudioParams() const
                               SampleFormat::kInternalFormat);
 }
 
-void ViewerWidget::StopBackgroundCache()
-{
-  cache_wait_timer_.stop();
-  if (cache_background_task_) {
-    cache_background_task_->Cancel();
-    cache_background_task_ = nullptr;
-  }
-}
-
 void ViewerWidget::UpdateStack()
 {
   if (GetConnectedNode()
@@ -807,8 +838,14 @@ void ViewerWidget::HashGenerated()
 
 void ViewerWidget::StartBackgroundCaching()
 {
-  if (Config::Current()["AutoCache"].toBool()) {
-    if (cache_background_task_) {
+  if (busy_) {
+    busy_viewers_--;
+    busy_ = false;
+  }
+
+  if (GetConnectedNode()->video_frame_cache()->HasInvalidatedRanges()
+      && Config::Current()["AutoCache"].toBool()) {
+    if (cache_background_task_ || busy_viewers_) {
 
       // Something else is caching right now, we don't want to do multiple at once so we'll check
       // again in our next interval
@@ -820,6 +857,8 @@ void ViewerWidget::StartBackgroundCaching()
                                              GenerateAudioParams(),
                                              false);
 
+      our_cache_background_task_ = cache_background_task_;
+
       TaskManager::instance()->AddTask(cache_background_task_);
     }
   }
@@ -834,6 +873,12 @@ void ViewerWidget::BackgroundCacheFinished(Task* t)
 
 void ViewerWidget::UpdateRendererParameters()
 {
+  if (cache_background_task_ == our_cache_background_task_) {
+    StopAllBackgroundCacheTasks(false);
+  }
+
+  StartBackgroundCaching();
+
   renderer_->SetVideoParams(GenerateVideoParams());
 
   renderer_->SetAudioParams(GenerateAudioParams());
@@ -979,25 +1024,8 @@ void ViewerWidget::Play()
 
 void ViewerWidget::Pause()
 {
-  if (IsPlaying()) {
-    AudioManager::instance()->StopOutput();
-    playback_speed_ = 0;
-    controls_->ShowPlayButton();
+  PauseInternal();
 
-    if (playback_is_audio_only_) {
-      disconnect(AudioManager::instance(), &AudioManager::OutputNotified, this, &ViewerWidget::PlaybackTimerUpdate);
-    } else {
-      disconnect(display_widget_, &ViewerDisplayWidget::frameSwapped, this, &ViewerWidget::PlaybackTimerUpdate);
-    }
-
-    foreach (ViewerWindow* window, windows_) {
-      window->Pause();
-    }
-
-    playback_queue_.clear();
-  }
-
-  prequeuing_ = false;
   StartBackgroundCaching();
 }
 
@@ -1006,7 +1034,7 @@ void ViewerWidget::ShuttleLeft()
   int current_speed = playback_speed_;
 
   if (current_speed != 0) {
-    Pause();
+    PauseInternal();
   }
 
   current_speed--;
@@ -1028,7 +1056,7 @@ void ViewerWidget::ShuttleRight()
   int current_speed = playback_speed_;
 
   if (current_speed != 0) {
-    Pause();
+    PauseInternal();
   }
 
   current_speed++;
@@ -1170,8 +1198,16 @@ void ViewerWidget::ViewerInvalidatedRange(const TimeRange &range)
   }
 
   // Restart the cache wait timer
-  StopBackgroundCache();
-  cache_wait_timer_.start();
+  cache_wait_timer_.stop();
+  StopAllBackgroundCacheTasks(false);
+
+  if (qApp->mouseButtons() & Qt::LeftButton) {
+    cache_wait_timer_.start();
+  } else {
+    StartBackgroundCaching();
+  }
+
+
 
   /*
   QList<rational> invalidated_frames = GetConnectedNode()->video_frame_cache()->GetFrameListFromTimeRange({range});

app/widget/viewer/viewer.h

@@ -98,7 +98,7 @@ public:
 
   void SetGizmos(Node* node);
 
-  static void StopAllBackgroundCacheTasks();
+  static void StopAllBackgroundCacheTasks(bool wait);
   static void SetBackgroundCacheTask(CacheTask* t);
 
 public slots:
@@ -172,6 +172,8 @@ private:
 
   void PlayInternal(int speed, bool in_to_out_only);
 
+  void PauseInternal();
+
   void PushScrubbedAudio();
 
   int CalculateDivider();
@@ -199,8 +201,6 @@ private:
   VideoRenderingParams GenerateVideoParams() const;
   AudioRenderingParams GenerateAudioParams() const;
 
-  void StopBackgroundCache();
-
   QStackedWidget* stack_;
 
   ViewerSizer* sizer_;
@@ -246,8 +246,14 @@ private:
 
   QTimer cache_wait_timer_;
 
+  bool busy_;
+
+  CacheTask* our_cache_background_task_;
+
   static CacheTask* cache_background_task_;
 
+  static int busy_viewers_;
+
 private slots:
   void PlaybackTimerUpdate();