render: avoid hashing null node

app/render/previewautocacher.cpp

@@ -76,7 +76,8 @@ QVector<PreviewAutoCacher::HashData> PreviewAutoCacher::GenerateHashes(ViewerOut
     const rational &time = times.at(i);
 
     // See if hash already exists in disk cache
-    QByteArray hash = RenderManager::Hash(viewer,
+    QByteArray hash = RenderManager::Hash(viewer->GetConnectedTextureOutput(),
+                                          viewer->GetConnectedTextureValueHint(),
                                           viewer->GetVideoParams(),
                                           time);
 
@@ -84,6 +85,7 @@ QVector<PreviewAutoCacher::HashData> PreviewAutoCacher::GenerateHashes(ViewerOut
     bool hash_exists = existing_hashes.contains(hash);
 
     if (!hash_exists) {
+      // FIXME: Using CachePathName here is NOT thread safe and should be replaced
       hash_exists = QFileInfo::exists(cache->CachePathName(hash));
 
       if (hash_exists) {
@@ -545,7 +547,9 @@ void PreviewAutoCacher::TryRender()
 
   // Check for newly invalidated video and hash it
   if (!invalidated_video_.isEmpty()) {
-    if (hash_iterator_.HasNext()) {
+    if (!copied_viewer_node_->GetConnectedTextureOutput()) {
+      hash_iterator_.reset();
+    } else if (hash_iterator_.HasNext()) {
       hash_iterator_.insert(invalidated_video_);
     } else {
       hash_iterator_ = TimeRangeListFrameIterator(invalidated_video_, viewer_node_->GetVideoParams().frame_rate_as_time_base());

app/render/rendermanager.cpp

@@ -102,13 +102,15 @@ void RenderManager::ClearOldDecoders()
 
 QByteArray RenderManager::Hash(const Node *n, const Node::ValueHint &output, const VideoParams &params, const rational &time)
 {
-  HashTraverser hasher;
-  return hasher.GetHash(n, output, params, TimeRange(time, time + params.frame_rate_as_time_base()));
-}
+  Q_ASSERT(n);
 
-QByteArray RenderManager::Hash(ViewerOutput *viewer, const VideoParams &params, const rational &time)
-{
-  return Hash(viewer->GetConnectedTextureOutput(), viewer->GetValueHintForInput(ViewerOutput::kTextureInput), params, time);
+  if (n) {
+    HashTraverser hasher;
+    return hasher.GetHash(n, output, params, TimeRange(time, time + params.frame_rate_as_time_base()));
+  } else {
+    qCritical() << "Hash called with null node";
+    return QByteArray();
+  }
 }
 
 RenderTicketPtr RenderManager::RenderFrame(ViewerOutput *viewer, ColorManager* color_manager,

app/render/rendermanager.h

@@ -67,7 +67,6 @@ public:
    * @brief Generate a unique identifier for a certain node at a cconst Node *n, const Node::ValueHint &outputertain time
    */
   static QByteArray Hash(const Node *n, const Node::ValueHint &output, const VideoParams &params, const rational &time);
-  static QByteArray Hash(ViewerOutput *viewer, const VideoParams &params, const rational &time);
 
   /**
    * @brief Asynchronously generate a frame at a given time