render: fix issue responding to cancelled tasks

app/render/CMakeLists.txt

@@ -24,6 +24,7 @@ set(OLIVE_SOURCES
   render/audioparams.h
   render/audioplaybackcache.cpp
   render/audioplaybackcache.h
+  render/cancelatom.h
   render/color.cpp
   render/color.h
   render/colorprocessor.cpp

app/render/cancelatom.h

@@ -0,0 +1,48 @@
+#ifndef CANCELATOM_H
+#define CANCELATOM_H
+
+#include <QMutex>
+
+namespace olive {
+
+class CancelAtom
+{
+public:
+  CancelAtom() :
+    cancelled_(false),
+    heard_(false)
+  {}
+
+  bool IsCancelled()
+  {
+    QMutexLocker locker(&mutex_);
+    if (cancelled_) {
+      heard_ = true;
+    }
+    return cancelled_;
+  }
+
+  void Cancel()
+  {
+    QMutexLocker locker(&mutex_);
+    cancelled_ = true;
+  }
+
+  bool HeardCancel()
+  {
+    QMutexLocker locker(&mutex_);
+    return heard_;
+  }
+
+private:
+  QMutex mutex_;
+
+  bool cancelled_;
+
+  bool heard_;
+
+};
+
+}
+
+#endif // CANCELATOM_H

app/render/renderprocessor.cpp

@@ -134,7 +134,7 @@ void RenderProcessor::Run()
   // Depending on the render ticket type, start a job
   RenderManager::TicketType type = ticket_->property("type").value<RenderManager::TicketType>();
 
-  SetCancelPointer(&ticket_->IsCancelled());
+  SetCancelPointer(ticket_->GetCancelAtom());
 
   SetCacheVideoParams(ticket_->property("vparam").value<VideoParams>());
   SetCacheAudioParams(ticket_->property("aparam").value<AudioParams>());