enough mind-blowing crazy code, lets do intra-ardour DnD the right way

git-svn-id: svn://localhost/ardour2/branches/2.0-ongoing@4245 d708f5d6-7413-0410-9779-e7cbd77b26cf

4 files changed, 49 insertions, 95 deletions

diff --git a/gtk2_ardour/redirect_box.cc b/gtk2_ardour/redirect_box.cc
index f0f06d12d6..25fa0191ad 100644
--- a/gtk2_ardour/redirect_box.cc
+++ b/gtk2_ardour/redirect_box.cc
@@ -121,7 +121,7 @@ RedirectBox::RedirectBox (Placement pcmnt, Session& sess, PluginSelector &plugse
 	redirect_display.get_column(0)->set_sizing(TREE_VIEW_COLUMN_FIXED);
 	redirect_display.get_column(0)->set_fixed_width(48);
 	redirect_display.add_object_drag (columns.redirect.index(), "redirects");
-	redirect_display.signal_object_drop.connect (mem_fun (*this, &RedirectBox::object_drop));
+	redirect_display.signal_drop.connect (mem_fun (*this, &RedirectBox::object_drop));
 
 	TreeViewColumn* name_col = redirect_display.get_column(0);
 	CellRendererText* renderer = dynamic_cast<CellRendererText*>(redirect_display.get_column_cell_renderer (0));
@@ -169,22 +169,8 @@ RedirectBox::route_going_away ()
 }
 
 void
-RedirectBox::object_drop (string type, uint32_t cnt, const boost::shared_ptr<Redirect>* ptr)
+RedirectBox::object_drop (const list<boost::shared_ptr<Redirect> >& redirects)
 {
-	cerr << "Object drop, type = " << type << " cnt = " << cnt << endl;
-
-	if (type != "redirects" || cnt == 0 || !ptr) {
-		return;
-	}
-
-	/* do something with the dropped redirects */
-
-	list<boost::shared_ptr<Redirect> > redirects;
-	
-	for (uint32_t n = 0; n < cnt; ++n) {
-		redirects.push_back (ptr[n]);
-	}
-	
 	paste_redirect_list (redirects);
 }
 
@@ -194,7 +180,6 @@ RedirectBox::update()
 	redisplay_redirects (0);
 }
 
-
 void
 RedirectBox::set_width (Width w)
 {
@@ -953,11 +938,11 @@ RedirectBox::paste_redirects ()
 }
 
 void
-RedirectBox::paste_redirect_list (list<boost::shared_ptr<Redirect> >& redirects)
+RedirectBox::paste_redirect_list (const list<boost::shared_ptr<Redirect> >& redirects)
 {
 	list<boost::shared_ptr<Redirect> > copies;
 
-	for (list<boost::shared_ptr<Redirect> >::iterator i = redirects.begin(); i != redirects.end(); ++i) {
+	for (list<boost::shared_ptr<Redirect> >::const_iterator i = redirects.begin(); i != redirects.end(); ++i) {
 
 		boost::shared_ptr<Redirect> copy = Redirect::clone (*i);
 
diff --git a/gtk2_ardour/redirect_box.h b/gtk2_ardour/redirect_box.h
index 0d0ce84bd2..bb00d820c3 100644
--- a/gtk2_ardour/redirect_box.h
+++ b/gtk2_ardour/redirect_box.h
@@ -125,7 +125,7 @@ class RedirectBox : public Gtk::HBox, public PluginInterestedObject
 	Gtkmm2ext::DnDTreeView<boost::shared_ptr<ARDOUR::Redirect> > redirect_display;
 	Gtk::ScrolledWindow    redirect_scroller;
 
-	void object_drop (std::string type, uint32_t cnt, const boost::shared_ptr<ARDOUR::Redirect>*);
+	void object_drop (const std::list<boost::shared_ptr<ARDOUR::Redirect> >&);
 
 	Width _width;
 	
@@ -184,7 +184,7 @@ class RedirectBox : public Gtk::HBox, public PluginInterestedObject
 	void get_selected_redirects (vector<boost::shared_ptr<ARDOUR::Redirect> >&);
 
 	static Glib::RefPtr<Gtk::Action> paste_action;
-	void paste_redirect_list (std::list<boost::shared_ptr<ARDOUR::Redirect> >& redirects);
+	void paste_redirect_list (const std::list<boost::shared_ptr<ARDOUR::Redirect> >& redirects);
 	
 	void activate_redirect (boost::shared_ptr<ARDOUR::Redirect>);
 	void deactivate_redirect (boost::shared_ptr<ARDOUR::Redirect>);
diff --git a/libs/gtkmm2ext/dndtreeview.cc b/libs/gtkmm2ext/dndtreeview.cc
index a840114def..0695dd3281 100644
--- a/libs/gtkmm2ext/dndtreeview.cc
+++ b/libs/gtkmm2ext/dndtreeview.cc
@@ -29,6 +29,8 @@ using namespace Gtk;
 using namespace Glib;
 using namespace Gtkmm2ext;
 
+DnDTreeViewBase::DragData DnDTreeViewBase::drag_data;
+
 DnDTreeViewBase::DnDTreeViewBase ()
 	: TreeView ()
 {
@@ -57,6 +59,7 @@ DnDTreeViewBase::add_object_drag (int column, string type_name)
 {
 	draggable.push_back (TargetEntry (type_name, TargetFlags(0)));
 	data_column = column;
+	object_type = type_name;
 
 	enable_model_drag_source (draggable);
 	enable_model_drag_dest (draggable);
diff --git a/libs/gtkmm2ext/gtkmm2ext/dndtreeview.h b/libs/gtkmm2ext/gtkmm2ext/dndtreeview.h
index e7f4aeb83d..08d54bb139 100644
--- a/libs/gtkmm2ext/gtkmm2ext/dndtreeview.h
+++ b/libs/gtkmm2ext/gtkmm2ext/dndtreeview.h
@@ -62,6 +62,21 @@ class DnDTreeViewBase : public Gtk::TreeView
 	std::list<Gtk::TargetEntry> draggable;
 	Gdk::DragAction             suggested_action;
 	int                         data_column;
+	std::string                 object_type;
+
+	struct DragData {
+	    Gtk::TreeView* source;
+	    int            data_column;
+	    std::string    object_type;
+	};
+	
+	static DragData drag_data;
+
+	void start_object_drag () {
+		drag_data.source = this;
+		drag_data.data_column = data_column;
+		drag_data.object_type = object_type;
+	}
 };
 
 template<class DataType>
@@ -71,26 +86,23 @@ class DnDTreeView : public DnDTreeViewBase
 	DnDTreeView() {} 
 	~DnDTreeView() {}
 
-	sigc::signal<void,std::string,uint32_t,const DataType*> signal_object_drop;
+	sigc::signal<void,const std::list<DataType>& > signal_drop;
 
 	void on_drag_data_get(const Glib::RefPtr<Gdk::DragContext>& context, Gtk::SelectionData& selection_data, guint info, guint time) {
 		if (selection_data.get_target() == "GTK_TREE_MODEL_ROW") {
 
 			TreeView::on_drag_data_get (context, selection_data, info, time);
-			
-		} else if (data_column >= 0) {
-			Gtk::TreeSelection::ListHandle_Path selection = get_selection()->get_selected_rows ();
-			SerializedObjectPointers<DataType>* sr = serialize_pointers (get_model(), &selection, selection_data.get_target());
-			selection_data.set (8, (guchar*)sr, sr->size);
-			/* we don't need the allocated block anymore,
-			   it will have been copied. this is wierd - 
-			   the objects we put into the block have
-			   effectively been moved into the copy
-			   made by Gtk::SelectionData::set(),
-			   leaving our memory block a mere ghost.
-			   we're just fixing a memory leak here.
-			*/
-			delete [] (reinterpret_cast<char*>(sr));
+
+		} else if (selection_data.get_target() == object_type) {
+
+			start_object_drag ();
+
+			/* we don't care about the data passed around by DnD, but
+			   we have to provide something otherwise it will stop.
+			 */
+
+			guchar c;
+			selection_data.set (8, (guchar*)&c, 1);
 		}
 	}
 	
@@ -108,30 +120,11 @@ class DnDTreeView : public DnDTreeViewBase
 			
 			TreeView::on_drag_data_received (context, x, y, selection_data, info, time);
 
-		} else if (data_column >= 0) {
-			
-			/* object D-n-D */
-			
-			const void* data = selection_data.get_data();
-			const SerializedObjectPointers<DataType>* sr = reinterpret_cast<const SerializedObjectPointers<DataType> *>(data);
-			
-			if (sr) {
-				signal_object_drop (sr->type, sr->cnt, sr->data);
-
-				/* now clean up the pointers in the blob.
-				   Note that we make an explicit call
-				   to the destructor rather than using
-				   delete - the object does not own
-				   the memory in which it lives - it 
-				   was allocated as a single contiguous
-				   block (see below).
-				 */
-
-				for (uint32_t x = 0; x < sr->cnt; ++x) {
-					sr->data[x].~DataType();
-				}
-			}
+
+		} else if (selection_data.get_target() == object_type) {
 			
+			end_object_drag ();
+
 		} else {
 			/* some kind of target type added by the app, which will be handled by a signal handler */
 		}
@@ -139,45 +132,18 @@ class DnDTreeView : public DnDTreeViewBase
 
   private:
 
-	SerializedObjectPointers<DataType>* serialize_pointers (Glib::RefPtr<Gtk::TreeModel> model, 
-								Gtk::TreeSelection::ListHandle_Path* selection,
-								Glib::ustring type) {
-
-		/* this nasty chunk of code is here because X's DnD protocol (probably other graphics UI's too) 
-		   requires that we package up the entire data collection for DnD in a single contiguous region
-		   (so that it can be trivially copied between address spaces). We don't know the type of DataType so
-		   we have to mix-and-match C and C++ programming techniques here to get the right result.
-
-		   The C trick is to use the "someType foo[0];" declaration trick to create a zero-sized array at the
-		   end of a SerializedObjectPointers<DataType object. Then we allocate a raw memory buffer that extends
-		   past that array and thus provides space for however many DataType items we actually want to pass
-		   around.
-
-		   The C++ trick is to use the placement operator new() syntax to initialize that extra
-		   memory properly.
-		*/
-		
-		uint32_t cnt = selection->size();
-		uint32_t sz = (sizeof (DataType) * cnt) + sizeof (SerializedObjectPointers<DataType>);
-
-		char* buf = new char[sz];
-		SerializedObjectPointers<DataType>* sr = (SerializedObjectPointers<DataType>*) buf;
-
-		for (uint32_t i = 0; i < cnt; ++i) {
-			new ((void *) &sr->data[i]) DataType ();
-		}
-		
-		sr->cnt = cnt;
-		sr->size = sz;
-		snprintf (sr->type, sizeof (sr->type), "%s", type.c_str());
-		
-		cnt = 0;
+	void end_object_drag () {
+		Glib::RefPtr<Gtk::TreeModel> model = drag_data.source->get_model();
+		DataType v;
+		std::list<DataType> l;
+		Gtk::TreeSelection::ListHandle_Path selection = drag_data.source->get_selection()->get_selected_rows ();
 		
-		for (Gtk::TreeSelection::ListHandle_Path::iterator x = selection->begin(); x != selection->end(); ++x, ++cnt) {
-			model->get_iter (*x)->get_value (data_column, sr->data[cnt]);
+		for (Gtk::TreeSelection::ListHandle_Path::iterator x = selection.begin(); x != selection.end(); ++x) {
+			model->get_iter (*x)->get_value (drag_data.data_column, v);
+			l.push_back (v);
 		}
 
-		return sr;
+		signal_drop (l);
 	}
 };