enforce read-only/stateless structure of new rendering system

Most if not all Node references are const now, so their state is entirely
held in the renderers rather than the Nodes themselves.

app/node/dependency.cpp

@@ -27,19 +27,19 @@ NodeDependency::NodeDependency() :
 {
 }
 
-NodeDependency::NodeDependency(Node *node, const TimeRange &range) :
+NodeDependency::NodeDependency(const Node *node, const TimeRange &range) :
   node_(node),
   range_(range)
 {
 }
 
-NodeDependency::NodeDependency(Node *node, const rational &in, const rational &out) :
+NodeDependency::NodeDependency(const Node *node, const rational &in, const rational &out) :
   node_(node),
   range_(in, out)
 {
 }
 
-Node *NodeDependency::node() const
+const Node *NodeDependency::node() const
 {
   return node_;
 }

app/node/dependency.h

@@ -30,16 +30,16 @@ class Node;
 class NodeDependency {
 public:
   NodeDependency();
-  NodeDependency(Node* node, const TimeRange& range);
-  NodeDependency(Node* node, const rational& in, const rational &out);
+  NodeDependency(const Node* node, const TimeRange& range);
+  NodeDependency(const Node* node, const rational& in, const rational &out);
 
-  Node* node() const;
+  const Node* node() const;
   const rational& in() const;
   const rational& out() const;
   const TimeRange& range() const;
 
 private:
-  Node* node_;
+  const Node* node_;
   TimeRange range_;
 };
 

app/node/input.cpp

@@ -55,7 +55,7 @@ QString NodeInput::name()
   return NodeParam::name();
 }
 
-const NodeParam::DataType &NodeInput::data_type()
+const NodeParam::DataType &NodeInput::data_type() const
 {
   return data_type_;
 }
@@ -65,7 +65,7 @@ void NodeInput::set_data_type(const NodeParam::DataType &type)
   data_type_ = type;
 }
 
-NodeOutput *NodeInput::get_connected_output()
+NodeOutput *NodeInput::get_connected_output() const
 {
   if (!edges_.isEmpty()) {
     return edges_.first()->output();
@@ -74,7 +74,7 @@ NodeOutput *NodeInput::get_connected_output()
   return nullptr;
 }
 
-Node *NodeInput::get_connected_node()
+Node *NodeInput::get_connected_node() const
 {
   NodeOutput* output = get_connected_output();
 
@@ -85,7 +85,7 @@ Node *NodeInput::get_connected_node()
   return nullptr;
 }
 
-QVariant NodeInput::get_value_at_time(const rational &time)
+QVariant NodeInput::get_value_at_time(const rational &time) const
 {
   if (is_keyframing()) {
     if (keyframes_.first().time() >= time) {
@@ -231,7 +231,7 @@ void NodeInput::set_value_at_time(const rational &time, const QVariant &value)
     emit ValueChanged(signal_vc_range.in(), signal_vc_range.out());
 }
 
-bool NodeInput::is_keyframing()
+bool NodeInput::is_keyframing() const
 {
   return keyframing_;
 }
@@ -241,22 +241,12 @@ void NodeInput::set_is_keyframing(bool k)
   keyframing_ = k;
 }
 
-bool NodeInput::dependent()
-{
-  return dependent_;
-}
-
-void NodeInput::set_dependent(bool d)
-{
-  dependent_ = d;
-}
-
-const QVariant &NodeInput::minimum()
+const QVariant &NodeInput::minimum() const
 {
   return minimum_;
 }
 
-bool NodeInput::has_minimum()
+bool NodeInput::has_minimum() const
 {
   return has_minimum_;
 }
@@ -267,12 +257,12 @@ void NodeInput::set_minimum(const QVariant &min)
   has_minimum_ = true;
 }
 
-const QVariant &NodeInput::maximum()
+const QVariant &NodeInput::maximum() const
 {
   return maximum_;
 }
 
-bool NodeInput::has_maximum()
+bool NodeInput::has_maximum() const
 {
   return has_maximum_;
 }

app/node/input.h

@@ -57,7 +57,7 @@ public:
    * This can be used in conjunction with NodeInput::can_accept_type() to determine whether this parameter can be
    * connected to it.
    */
-  const DataType& data_type();
+  const DataType& data_type() const;
   void set_data_type(const DataType& type);
 
   /**
@@ -67,7 +67,7 @@ public:
    *
    * The output parameter if connected or nullptr if not
    */
-  NodeOutput* get_connected_output();
+  NodeOutput* get_connected_output() const;
 
   /**
    * @brief If this input is connected to an output, retrieve the Node whose output is connected
@@ -76,12 +76,12 @@ public:
    *
    * The connected Node if connected or nullptr if not
    */
-  Node* get_connected_node();
+  Node* get_connected_node() const;
 
   /**
    * @brief Calculate what the stored value should be at a certain time
    */
-  QVariant get_value_at_time(const rational& time);
+  QVariant get_value_at_time(const rational& time) const;
 
   /**
    * @brief Sets what value should be seen at a specific time
@@ -91,31 +91,19 @@ public:
   /**
    * @brief Return whether keyframing is enabled on this input or not
    */
-  bool is_keyframing();
+  bool is_keyframing() const;
 
   /**
    * @brief Set whether keyframing is enabled on this input or not
    */
   void set_is_keyframing(bool k);
 
-  /**
-   * @brief Return whether the Node is dependent on this input or not
-   *
-   * \see set_dependent()
-   */
-  bool dependent();
-
-  /**
-   * @brief Set whether the Node is dependent on this input
-   */
-  void set_dependent(bool d);
-
-  const QVariant& minimum();
-  bool has_minimum();
+  const QVariant& minimum() const;
+  bool has_minimum() const;
   void set_minimum(const QVariant& min);
 
-  const QVariant& maximum();
-  bool has_maximum();
+  const QVariant& maximum() const;
+  bool has_maximum() const;
   void set_maximum(const QVariant& max);
 
   /**