indexing
	description: "Destionation of a drag'n'drop: GtkTreeView drag-and-drop Interface for drag-and-drop support in GtkTreeView"
	copyright: "[
					Copyright (C) 2006 eiffel-libraries team, GTK+ team
					
					This library is free software; you can redistribute it and/or
					modify it under the terms of the GNU Lesser General Public License
					as published by the Free Software Foundation; either version 2.1 of
					the License, or (at your option) any later version.
					
					This library 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
					Lesser General Public License for more details.

					You should have received a copy of the GNU Lesser General Public
					License along with this library; if not, write to the Free Software
					Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
					02110-1301 USA
					]"

deferred class GTK_TREE_DRAG_DEST
	-- GTK+ supports Drag-and-Drop in tree views with a high-level and
	-- a low-level API.
	
	-- The low-level API consists of the GTK+ DND API, augmented by
	-- some treeview utility functions: GTK_TREE_VIEW's
	-- set_drag_dest_row, get_drag_dest_row, get_dest_row_at_pos,
	-- create_row_drag_icon, set_row_drag_data and
	-- get_row_drag_data. This API leaves a lot of flexibility, but
	-- nothing is done automatically, and implementing advanced
	-- features like hover-to-open-rows or autoscrolling on top of this
	-- API is a lot of work.
	
	-- On the other hand, if you write to the high-level API, then all
	-- the bookkeeping of rows is done for you, as well as things like
	-- hover-to-open and auto-scroll, but your models have to implement
	-- the GtkTreeDragSource and GtkTreeDragDest interfaces.

inherit G_OBJECT
	
	-- Object Hierarchy: inherits from GInterface

	-- Known Implementations: GtkTreeDragSource is implemented by
	-- GtkTreeModelSort, GtkTreeStore, GtkListStore and
	-- GtkTreeModelFilter.

	-- GtkTreeDragDest is implemented by GtkTreeStore and GtkListStore.
feature -- 
	is_last_action_successful: BOOLEAN
		
	receive_data (a_path: GTK_TREE_PATH; a_selection_data: GTK_SELECTION_DATA) is
			-- Try to insert a row before `a_path', deriving the contents
			-- of the row from
			-- `a_selection_data'. `is_last_action_successful' will be
			-- False if `a_path' is outside the tree so that inserting
			-- before it is impossible; it will also be False if the new
			-- row is not created for some model-specific reason. Should
			-- robustly handle a dest no longer found in the model!
		require 
			valid_path: a_path /= Void
			valid_data: a_selection_data /= Void
		do
			is_last_action_successful :=
				(gtk_tree_drag_dest_drag_data_received
				 (handle, a_path.handle, a_selection_data.handle)).to_boolean
		end
	
	is_row_drop_possible (a_path: GTK_TREE_PATH; a_selection_data: GTK_SELECTION_DATA): BOOLEAN is
			-- Determines whether a drop is possible before the given
			-- dest_path, at the same depth as dest_path. i.e., can we
			-- drop the data in selection_data at that
			-- location. dest_path does not have to exist; the return
			-- value will almost certainly be FALSE if the parent of
			-- dest_path doesn't exist, though.
		
			-- drag_dest : 	a GtkTreeDragDest
			-- dest_path : 	destination row
			-- selection_data : 	the data being dragged
			-- Returns : 	TRUE if a drop is possible before dest_path
		require 
			valid_path: a_path /= Void
			valid_data: a_selection_data /= Void
		do
			Result := (gtk_tree_drag_dest_row_drop_possible
						  (handle, a_path.handle, a_selection_data.handle)).to_boolean
		end



feature -- TODO: GtkTreeDragDestIface

	-- typedef struct {
	--   GTypeInterface g_iface;
	
	--   /* VTable - not signals */
	
	--   gboolean     (* drag_data_received) (GtkTreeDragDest   *drag_dest,
	-- 													GtkTreePath       *dest,
	-- 													GtkSelectionData  *selection_data);
	
	--   gboolean     (* row_drop_possible)  (GtkTreeDragDest   *drag_dest,
	-- 													GtkTreePath       *dest_path,
	-- 						                     GtkSelectionData  *selection_data);
	-- } GtkTreeDragDestIface;


	-- gtk_tree_set_row_drag_data ()
	
	-- gboolean    gtk_tree_set_row_drag_data      (GtkSelectionData *selection_data,
	-- 															GtkTreeModel *tree_model,
	-- 															GtkTreePath *path);

	-- Sets selection data of target type GTK_TREE_MODEL_ROW. Normally used in a drag_data_get handler.

	-- selection_data : 	some GtkSelectionData
	-- tree_model : 	a GtkTreeModel
	-- path : 	a row in tree_model
	-- Returns : 	TRUE if the GtkSelectionData had the proper target type to allow us to set a tree row
	-- gtk_tree_get_row_drag_data ()

	-- gboolean    gtk_tree_get_row_drag_data      (GtkSelectionData *selection_data,
	-- 															GtkTreeModel **tree_model,
	-- 															GtkTreePath **path);

	-- Obtains a tree_model and path from selection data of target type GTK_TREE_MODEL_ROW. Normally called from a drag_data_received handler. This function can only be used if selection_data originates from the same process that's calling this function, because a pointer to the tree model is being passed around. If you aren't in the same process, then you'll get memory corruption. In the GtkTreeDragDest drag_data_received handler, you can assume that selection data of type GTK_TREE_MODEL_ROW is in from the current process. The returned path must be freed with gtk_tree_path_free().

	-- selection_data : 	a GtkSelectionData
	-- tree_model : 	a GtkTreeModel
	-- path : 	row in tree_model
	-- Returns : 	TRUE if selection_data had target type GTK_TREE_MODEL_ROW and is otherwise valid
feature {} -- External calls
	gtk_tree_drag_dest_drag_data_received (a_drag_dest: POINTER; -- GtkTreeDragDest*
														a_dest: POINTER; -- GtkTreePath*
														a_selection_data: POINTER -- GtkSelectionData*
														): INTEGER is -- gboolean
		external "C use <gtk/gtk.h>"
		end
	
	gtk_tree_drag_dest_row_drop_possible (a_drag_dest: POINTER; -- GtkTreeDragDest*
													  a_dest_path: POINTER; -- GtkTreePath *
													  a_selection_data: POINTER -- GtkSelectionData
													  ): INTEGER is -- gboolean
		external "C use <gtk/gtk.h>"
		end

-- 	gtk_tree_set_row_drag_data (a_selection_data: POINTER; -- GtkSelectionData*
-- 										 a_tree_model: POINTER; -- GtkTreeModel*
-- 										 a_path: POINTER; -- GtkTreePath*
-- 										 ): INTEGER is -- gboolean
-- 		external "C use <gtk/gtk.h>"
-- 		end
	
-- 	gtk_tree_get_row_drag_data (a_selection_data: POINTER; -- GtkSelectionData
-- 										 a_tree_model_handle: POINTER -- GtkTreeModel **
-- 										 a_path_handle: POINTER -- GtkTreePath **path
-- 										 ): INTEGER is -- gboolean
-- 		external "C use <gtk/gtk.h>"
-- 		end

feature {}	-- TODO: wrap - if necessary - GtkTreeDragSourceIface
	
	-- typedef struct _GtkTreeDragSource GtkTreeDragSource;



	-- typedef struct {
	--   GTypeInterface g_iface;

	--   /* VTable - not signals */

	--   gboolean     (* row_draggable)        (GtkTreeDragSource   *drag_source,
	-- 													  GtkTreePath         *path);

	--   gboolean     (* drag_data_get)        (GtkTreeDragSource   *drag_source,
	-- 													  GtkTreePath         *path,
	-- 													  GtkSelectionData    *selection_data);

	--   gboolean     (* drag_data_delete)     (GtkTreeDragSource *drag_source,
	-- 													  GtkTreePath       *path);
	-- } GtkTreeDragSourceIface;

end