fix merge conflict from master
[ardour.git] / libs / gtkmm2ext / gtkmm2ext / dndtreeview.h
index f8beb75873fcb4c5d3051edab5286c0c400ad96e..b5f18fa8902c7545d05c057898a07821dcf105e6 100644 (file)
@@ -1,3 +1,22 @@
+/*
+    Copyright (C) 2000-2007 Paul Davis 
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
 #ifndef __gtkmm2ext_dndtreeview_h__
 #define __gtkmm2ext_dndtreeview_h__
 
@@ -26,6 +45,11 @@ class DnDTreeViewBase : public Gtk::TreeView
 
        void add_drop_targets (std::list<Gtk::TargetEntry>&);
        void add_object_drag (int column, std::string type_name);
+
+       void on_drag_begin (Glib::RefPtr<Gdk::DragContext> const & context) {
+               Gtk::TreeView::on_drag_begin (context);
+               start_object_drag ();
+       }
        
        void on_drag_leave(const Glib::RefPtr<Gdk::DragContext>& context, guint time) {
                suggested_action = context->get_suggested_action();
@@ -43,6 +67,23 @@ class DnDTreeViewBase : public Gtk::TreeView
        std::list<Gtk::TargetEntry> draggable;
        Gdk::DragAction             suggested_action;
        int                         data_column;
+       std::string                 object_type;
+
+       struct DragData {
+           DragData () : source (0) {}
+               
+           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>
@@ -52,21 +93,24 @@ 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>&,Gtk::TreeView*,int,int,Glib::RefPtr<Gdk::DragContext>&> 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);
+
+               } else if (selection_data.get_target() == object_type) {
+
+                       /* 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);
                }
        }
-
+       
        void on_drag_data_received(const Glib::RefPtr<Gdk::DragContext>& context, int x, int y, const Gtk::SelectionData& selection_data, guint info, guint time) {
                if (suggested_action) {
                        /* this is a drag motion callback. just update the status to
@@ -81,64 +125,47 @@ 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);
-                       }
+
+               } else if (selection_data.get_target() == object_type) {
                        
+                       end_object_drag (const_cast<Glib::RefPtr<Gdk::DragContext>& > (context), x, y);
+
                } else {
                        /* some kind of target type added by the app, which will be handled by a signal handler */
                }
        }
 
-  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.
+       /**
+        * This can be called by the Treeview itself or by some other
+        * object that wants to get the list of dragged items.
+        */
 
-                  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;
+       void get_object_drag_data (std::list<DataType>& l, Gtk::TreeView** source) {
 
-               for (uint32_t i = 0; i < cnt; ++i) {
-                       new ((void *) &sr->data[i]) DataType ();
+               if (drag_data.source == 0) {
+                       return;
                }
+                       
+               Glib::RefPtr<Gtk::TreeModel> model = drag_data.source->get_model();
+               DataType v;
+               Gtk::TreeSelection::ListHandle_Path selection = drag_data.source->get_selection()->get_selected_rows ();
                
-               sr->cnt = cnt;
-               sr->size = sz;
-               snprintf (sr->type, sizeof (sr->type), "%s", type.c_str());
-               
-               cnt = 0;
-               
-               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);
                }
+               
+               *source = drag_data.source;
+       }
 
-               return sr;
+  private:
+       void end_object_drag (Glib::RefPtr<Gdk::DragContext>& context, int x, int y) {
+               std::list<DataType> l;
+               Gtk::TreeView* source;
+               get_object_drag_data (l, &source);
+               signal_drop (l, source, x, y, context);
        }
+
 };
 
 } // namespace