implemented new block system

Fixes recurring design issue that the Blocks were a frequent exception to the
DAG concept. The Blocks connecting to each others inputs/outputs while not
necessarily being "dependent" on each other to produce an image continually
causes issues while trying to create a rendering code path. This redesign
should provide a more "directed" approach to the directed acyclic graph.

app/node/block/block.cpp

@@ -31,9 +31,6 @@ Block::Block() :
 
   buffer_output_ = new NodeOutput("buffer_out");
   AddParameter(buffer_output_);
-
-  connect(this, SIGNAL(EdgeAdded(NodeEdgePtr)), this, SLOT(EdgeAddedSlot(NodeEdgePtr)), Qt::DirectConnection);
-  connect(this, SIGNAL(EdgeRemoved(NodeEdgePtr)), this, SLOT(EdgeRemovedSlot(NodeEdgePtr)), Qt::DirectConnection);
 }
 
 QString Block::Category()
@@ -51,6 +48,16 @@ const rational &Block::out()
   return out_point_;
 }
 
+void Block::set_in(const rational &in)
+{
+  in_point_ = in;
+}
+
+void Block::set_out(const rational &out)
+{
+  out_point_ = out;
+}
+
 const rational& Block::length()
 {
   return length_;
@@ -60,13 +67,17 @@ void Block::set_length(const rational &length)
 {
   Q_ASSERT(length > 0);
 
+  if (length == length_) {
+    return;
+  }
+
   LockUserInput();
 
   length_ = length;
 
   UnlockUserInput();
 
-  Refresh();
+  emit LengthChanged(length_);
 }
 
 void Block::set_length_and_media_in(const rational &length)
@@ -88,6 +99,16 @@ Block *Block::next()
   return next_;
 }
 
+void Block::set_previous(Block *previous)
+{
+  previous_ = previous;
+}
+
+void Block::set_next(Block *next)
+{
+  next_ = next;
+}
+
 QVariant Block::Value(NodeOutput *output)
 {
   if (output == block_output_) {
@@ -98,25 +119,6 @@ QVariant Block::Value(NodeOutput *output)
   return 0;
 }
 
-void Block::Refresh()
-{
-  // Set in point to the out point of the previous Node
-  if (previous() != nullptr) {
-    in_point_ = previous()->out();
-  } else {
-    in_point_ = 0;
-  }
-
-  // Update out point by adding this clip's length to the just calculated in point
-  out_point_ = in_point_ + length();
-
-  emit Refreshed();
-
-  if (next() != nullptr) {
-    next()->Refresh();
-  }
-}
-
 NodeOutput *Block::buffer_output()
 {
   return buffer_output_;

app/node/block/block.h

@@ -42,7 +42,7 @@ public:
   enum Type {
     kClip,
     kGap,
-    kEnd
+    kTrack
   };
 
   virtual Type type() = 0;
@@ -51,6 +51,8 @@ public:
 
   const rational& in();
   const rational& out();
+  void set_in(const rational& in);
+  void set_out(const rational& out);
 
   const rational &length();
   void set_length(const rational &length);
@@ -58,6 +60,8 @@ public:
 
   Block* previous();
   Block* next();
+  void set_previous(Block* previous);
+  void set_next(Block* next);
 
   NodeOutput* buffer_output();
   NodeOutput* block_output();
@@ -80,20 +84,6 @@ public:
   virtual QVariant Value(NodeOutput* output) override;
 
 public slots:
-  /**
-   * @brief Refreshes internal cache of in/out points up to date
-   *
-   * A block can only know truly know its in point by adding all the lengths of the clips before it. Since this can
-   * become timeconsuming, blocks cache their in and out points for easy access, however this does mean their caches
-   * need to stay up to date to provide accurate results. Whenever this or any surrounding Block is changed, it's
-   * recommended to call Refresh().
-   *
-   * This function specifically sets the in point to the out point of the previous clip and sets its out point to the
-   * in point + this block's length. Therefore, before calling Refresh() on a Block, it's necessary that all the
-   * Blocks before it are accurate and up to date. You may need to traverse through the Block list (using previous())
-   * and run Refresh() on all Blocks sequentially.
-   */
-  virtual void Refresh();
 
 signals:
   /**
@@ -103,6 +93,8 @@ signals:
    */
   void Refreshed();
 
+  void LengthChanged(const rational& length);
+
 protected:
   rational SequenceToMediaTime(const rational& sequence_time);
 
@@ -110,18 +102,18 @@ protected:
 
   static void CopyParameters(Block* source, Block* dest);
 
+  Block* previous_;
+  Block* next_;
+
 private:
   NodeOutput* block_output_;
   NodeOutput* buffer_output_;
 
-  rational in_point_;
-  rational out_point_;
-
   rational length_;
   rational media_in_;
 
-  Block* previous_;
-  Block* next_;
+  rational in_point_;
+  rational out_point_;
 
   QString block_name_;