renderer: copy cache path before render to avoid race conditions

app/render/backend/renderbackend.cpp

@@ -430,7 +430,7 @@ void RenderBackend::RunNextJob()
       worker->SetRenderMode(render_mode_);
       worker->SetPreviewGenerationEnabled(generate_audio_previews_);
       worker->SetCopyMap(&copy_map_);
-      worker->SetViewerNode(viewer_node_);
+      worker->SetCachePath(viewer_node_->video_frame_cache()->GetCacheDirectory());
 
       // Move ticket from queue to running list
       RenderTicketPtr ticket = render_queue_.front();

app/render/backend/renderworker.cpp

@@ -318,10 +318,11 @@ QVariant RenderWorker::ProcessFrameGeneration(const Node* node, const GenerateJo
 QVariant RenderWorker::GetCachedFrame(const Node* node, const rational& time)
 {
   if (render_mode_ == RenderMode::kOffline
+      && !cache_path_.isEmpty()
       && node->id() == QStringLiteral("org.olivevideoeditor.Olive.videoinput")) {
     QByteArray hash = HashNode(node, video_params(), time);
 
-    FramePtr f = viewer_->video_frame_cache()->LoadCacheFrame(hash);
+    FramePtr f = FrameHashCache::LoadCacheFrame(cache_path_, hash);
 
     if (f) {
       // The cached frame won't load with the correct divider by default, so we enforce it here

app/render/backend/renderworker.h

@@ -50,11 +50,6 @@ public:
     available_ = a;
   }
 
-  void SetViewerNode(ViewerOutput* viewer)
-  {
-    viewer_ = viewer;
-  }
-
   void SetVideoParams(const VideoParams& params)
   {
     video_params_ = params;
@@ -90,6 +85,11 @@ public:
     generate_audio_previews_ = e;
   }
 
+  void SetCachePath(const QString& s)
+  {
+    cache_path_ = s;
+  }
+
   void Hash(RenderTicketPtr ticket, ViewerOutput* viewer, const QVector<rational>& times);
 
   /**
@@ -186,14 +186,14 @@ private:
 
   bool generate_audio_previews_;
 
-  ViewerOutput* viewer_;
-
   QHash<Node*, Node*>* copy_map_;
 
   RenderMode::Mode render_mode_;
 
   QTimer* cleanup_timer_;
 
+  QString cache_path_;
+
   static const int kMaxDecoderLife;
 
 private slots:

app/render/framehashcache.cpp

@@ -220,12 +220,17 @@ bool FrameHashCache::SaveCacheFrame(const QByteArray &hash, FramePtr frame) cons
   }
 }
 
+FramePtr FrameHashCache::LoadCacheFrame(const QString &cache_path, const QByteArray &hash)
+{
+  return LoadCacheFrame(CachePathName(cache_path, hash));
+}
+
 FramePtr FrameHashCache::LoadCacheFrame(const QByteArray &hash) const
 {
   return LoadCacheFrame(CachePathName(hash));
 }
 
-FramePtr FrameHashCache::LoadCacheFrame(const QString &fn) const
+FramePtr FrameHashCache::LoadCacheFrame(const QString &fn)
 {
   FramePtr frame = nullptr;
 
@@ -371,10 +376,15 @@ void FrameHashCache::ProjectInvalidated(Project *p)
 }
 
 QString FrameHashCache::CachePathName(const QByteArray& hash) const
+{
+  return CachePathName(GetCacheDirectory(), hash);
+}
+
+QString FrameHashCache::CachePathName(const QString &cache_path, const QByteArray &hash)
 {
   QString ext = GetFormatExtension();
 
-  QDir cache_dir(QDir(GetCacheDirectory()).filePath(QString(hash.left(1).toHex())));
+  QDir cache_dir(QDir(cache_path).filePath(QString(hash.left(1).toHex())));
   cache_dir.mkpath(".");
 
   QString filename = QStringLiteral("%1%2").arg(QString(hash.mid(1).toHex()), ext);
@@ -383,7 +393,7 @@ QString FrameHashCache::CachePathName(const QByteArray& hash) const
   QMetaObject::invokeMethod(DiskManager::instance(),
                             "Accessed",
                             Qt::QueuedConnection,
-                            Q_ARG(QString, GetCacheDirectory()),
+                            Q_ARG(QString, cache_path),
                             Q_ARG(QByteArray, hash));
 
   return cache_dir.filePath(filename);

app/render/framehashcache.h

@@ -59,12 +59,14 @@ public:
    * @brief Return the path of the cached image at this time
    */
   QString CachePathName(const QByteArray &hash) const;
+  static QString CachePathName(const QString& cache_path, const QByteArray &hash);
 
   bool SaveCacheFrame(const QString& filename, char *data, const VideoParams &vparam, int linesize_bytes) const;
   bool SaveCacheFrame(const QByteArray& hash, char *data, const VideoParams &vparam, int linesize_bytes) const;
   bool SaveCacheFrame(const QByteArray& hash, FramePtr frame) const;
+  static FramePtr LoadCacheFrame(const QString& cache_path, const QByteArray& hash);
   FramePtr LoadCacheFrame(const QByteArray& hash) const;
-  FramePtr LoadCacheFrame(const QString& fn) const;
+  static FramePtr LoadCacheFrame(const QString& fn);
 
   static QString GetFormatExtension();
 

app/render/playbackcache.h

@@ -67,6 +67,8 @@ public:
     return !invalidated_.isEmpty();
   }
 
+  QString GetCacheDirectory() const;
+
 signals:
   void Invalidated(const OLIVE_NAMESPACE::TimeRange& r);
 
@@ -87,8 +89,6 @@ protected:
 
   Project* GetProject() const;
 
-  QString GetCacheDirectory() const;
-
   struct JobIdentifier {
     TimeRange range;
     qint64 job_time;