Tidied and documented Track::find_parent

src/gui/model/track.cpp

@@ -21,6 +21,7 @@
 * *****************************************************/
 
 #include "track.hpp"
+#include "parent-track.hpp"
 #include <boost/foreach.hpp>
 
 using namespace boost;
@@ -72,8 +73,8 @@ Track::print_branch()
   return print_branch_recursive(0);
 }
 
-shared_ptr<Track>
+shared_ptr<ParentTrack>
-Track::find_parent(shared_ptr<Track> root, shared_ptr<Track> child)
+Track::find_parent(shared_ptr<ParentTrack> root, shared_ptr<Track> child)
 { 
   REQUIRE(root != NULL);
   REQUIRE(child != NULL);
@@ -83,12 +84,19 @@ Track::find_parent(shared_ptr<Track> root, shared_ptr<Track> child)
       if(track == child)
         return root;
     
-      shared_ptr<Track> result = find_parent(track, child);
+      shared_ptr<ParentTrack> parent_track = 
+        dynamic_pointer_cast<model::ParentTrack, model::Track>(
+          track);
+      if(parent_track)
+        {
+          shared_ptr<ParentTrack> result = find_parent(
+            parent_track, child);
           if(result)
             return result;
         }
+    }
   
-  return shared_ptr<Track>();
+  return shared_ptr<ParentTrack>();
 }
 
 string

src/gui/model/track.hpp

@@ -32,6 +32,8 @@
 namespace gui {
 namespace model {
   
+class ParentTrack;
+
 /**
  * The model representation of a track. This is the base class for all
  * types of track that are implemented.
@@ -89,10 +91,18 @@ public:
    **/
   virtual std::string print_track() = 0;
   
-protected:
+public:
   
-  static boost::shared_ptr<Track>
+  /**
-    find_parent(boost::shared_ptr<Track> root,
+   * A utility function that attempts to find the parent of a track by
+   * searching through the tree from a root downward.
+   * @param root The root track to begin searching down from.
+   * @param child The child track to find the parent of.
+   * @return Returns the parent track if one was found, or an empty
+   * shared_ptr if none was found.
+   **/
+  static boost::shared_ptr<ParentTrack>
+    find_parent(boost::shared_ptr<ParentTrack> root,
       boost::shared_ptr<Track> child);
   
 protected:

src/gui/widgets/timeline/timeline-layout-helper.cpp

@@ -563,9 +563,8 @@ TimelineLayoutHelper::apply_drop_to_model_tree(
   
   // Detach the track from the old parent
   shared_ptr<model::ParentTrack> old_parent =
-    dynamic_pointer_cast<model::ParentTrack, model::Track>(
       model::Track::find_parent(
-        timelineWidget.sequence, dragging_track));
+        timelineWidget.sequence, dragging_track);
   REQUIRE(old_parent);  // The track must have a parent
   old_parent->get_child_track_list().remove(dragging_track);
   
@@ -573,9 +572,8 @@ TimelineLayoutHelper::apply_drop_to_model_tree(
     {
       // Find the new parent track
       shared_ptr<model::ParentTrack> new_parent =
-        dynamic_pointer_cast<model::ParentTrack, model::Track>(
         model::Track::find_parent(
-            timelineWidget.sequence, target_track));
+          timelineWidget.sequence, target_track);
       REQUIRE(new_parent);  // The track must have a parent
       
       // Find the destination point