nemo-list-view: Restrict drag-into-folder actions to be triggered

only over text-covered regions of a given row.

Dropping onto blank area of a folder row will now be considered a
background drop (added/moved to the current location), the same
as non-folder rows.

Author: mtwebster

eel/eel-gdk-extensions.c

@@ -73,3 +73,17 @@ eel_gdk_parse_geometry (const char *string, int *x_return, int *y_return,
 
 	return gdk_flags;
 }
+
+GdkDevice *
+eel_gdk_get_pointer_device (void)
+{
+    GdkSeat *seat;
+
+    seat = gdk_display_get_default_seat (gdk_display_get_default ());
+
+    if (seat != NULL) {
+        return gdk_seat_get_pointer (seat);
+    }
+
+    return NULL;
+}

eel/eel-gdk-extensions.h

@@ -47,4 +47,5 @@ EelGdkGeometryFlags eel_gdk_parse_geometry                 (const char
 							    guint               *width_return,
 							    guint               *height_return);
 
+GdkDevice *eel_gdk_get_pointer_device                      (void);
 #endif /* EEL_GDK_EXTENSIONS_H */

eel/eel-gtk-extensions.c

@@ -31,6 +31,7 @@
 
 #include "eel-glib-extensions.h"
 #include "eel-gnome-extensions.h"
+#include "eel-gdk-extensions.h"
 #include "eel-string.h"
 
 #include <X11/Xlib.h>
@@ -376,3 +377,63 @@ eel_gtk_get_window_xid (GtkWindow *window)
 
     return gdk_x11_window_get_xid (gdkw);
 }
+
+gboolean
+eel_gtk_get_treeview_pointer_location (GtkTreeView *treeview,
+                               gint *x, gint *y)
+{
+    GdkWindow *bin_window;
+
+    gint out_x, out_y;
+
+    *x = *y = 0;
+
+    bin_window = gtk_tree_view_get_bin_window (treeview);
+
+    if (bin_window != NULL) {
+        GdkDevice *device = eel_gdk_get_pointer_device ();
+        if (device != NULL) {
+            gdk_window_get_device_position (bin_window, device, &out_x, &out_y, NULL);
+
+            *x = out_x;
+            *y = out_y;
+
+            return TRUE;
+        }
+    }
+
+    return FALSE;
+}
+
+gboolean
+eel_gtk_get_treeview_row_text_is_under_pointer (GtkTreeView *tree_view)
+{
+    gint x, y;
+
+    if (eel_gtk_get_treeview_pointer_location (tree_view, &x, &y)) {
+        GdkRectangle area;
+        GtkTreePath *path;
+        GtkTreeViewColumn *column;
+
+        // A positive is_blank_at_pos is a reliable result.
+        if (gtk_tree_view_is_blank_at_pos (tree_view, x, y, &path, &column, NULL, NULL)) {
+            return FALSE;
+        }
+
+        // If not, there's an additional check to do, as the small gap (1px?) between rows
+        // can cause is_blank_at_pos to incorrectly return FALSE when that's not actually the case.
+        // Make sure the pointer position is actually inside the cell's bounds, and ignore edge
+        // events.
+        gtk_tree_view_get_cell_area (tree_view, path, column, &area);
+        if (x > area.x && x < area.x + area.width &&
+            y > area.y && y < area.y + area.height) {
+            return TRUE;
+        }
+
+        return FALSE;
+    }
+
+    // If we can't figure out the location, we need to default to allowing the operation. The highlighting will
+    // be accurate, so the user knows.
+    return TRUE;
+}

eel/eel-gtk-extensions.h

@@ -55,4 +55,7 @@ void                  eel_gtk_message_dialog_set_details_label        (GtkMessag
 								       const gchar               *details_text);
 
 XID                   eel_gtk_get_window_xid                          (GtkWindow *window);
+gboolean              eel_gtk_get_treeview_pointer_location           (GtkTreeView *treeview,
+                                                                       gint *x, gint *y);
+gboolean              eel_gtk_get_treeview_row_text_is_under_pointer  (GtkTreeView *tree_view);
 #endif /* EEL_GTK_EXTENSIONS_H */

libnemo-private/nemo-tree-view-drag-dest.c

@@ -38,6 +38,7 @@
 #include "nemo-link.h"
 
 #include <gtk/gtk.h>
+#include <eel/eel-gtk-extensions.h>
 
 #include <stdio.h>
 #include <string.h>
@@ -67,6 +68,7 @@ struct _NemoTreeViewDragDestDetails {
     gboolean desktop_dnd_can_delete_source;
 
 	char *direct_save_uri;
+    gboolean strict_drop;
 };
 
 enum {
@@ -506,7 +508,15 @@ drag_motion_callback (GtkWidget *widget,
 					 NULL);
 
 	if (action) {
-		set_drag_dest_row (dest, drop_path);
+        if (dest->details->strict_drop) {
+            if (eel_gtk_get_treeview_row_text_is_under_pointer (GTK_TREE_VIEW (widget))) {
+                set_drag_dest_row (dest, drop_path);
+            } else {
+                clear_drag_dest_row (dest);
+            }
+        } else {
+            set_drag_dest_row (dest, drop_path);
+        }
 		model = gtk_tree_view_get_model (GTK_TREE_VIEW (widget));
 		if (drop_path == NULL || (old_drop_path != NULL &&
 		    gtk_tree_path_compare (old_drop_path, drop_path) != 0)) {
@@ -1154,7 +1164,7 @@ nemo_tree_view_drag_dest_class_init (NemoTreeViewDragDestClass *class)
 
 
 NemoTreeViewDragDest *
-nemo_tree_view_drag_dest_new (GtkTreeView *tree_view)
+nemo_tree_view_drag_dest_new (GtkTreeView *tree_view, gboolean strict_drop)
 {
 	NemoTreeViewDragDest *dest;
 	GtkTargetList *targets;
@@ -1164,6 +1174,7 @@ nemo_tree_view_drag_dest_new (GtkTreeView *tree_view)
 	dest->details->tree_view = tree_view;
     dest->details->desktop_dnd_source_fs = NULL;
     dest->details->desktop_dnd_can_delete_source = FALSE;
+    dest->details->strict_drop = strict_drop;
 	g_object_weak_ref (G_OBJECT (dest->details->tree_view),
 			   tree_view_weak_notify, dest);
 

libnemo-private/nemo-tree-view-drag-dest.h

@@ -93,7 +93,7 @@ struct _NemoTreeViewDragDestClass {
 };
 
 GType                     nemo_tree_view_drag_dest_get_type (void);
-NemoTreeViewDragDest *nemo_tree_view_drag_dest_new      (GtkTreeView *tree_view);
+NemoTreeViewDragDest *nemo_tree_view_drag_dest_new      (GtkTreeView *tree_view, gboolean strict_drop);
 
 G_END_DECLS
 

src/nemo-list-view.c

@@ -38,6 +38,7 @@
 #include <string.h>
 #include <eel/eel-vfs-extensions.h>
 #include <eel/eel-gdk-extensions.h>
+#include <eel/eel-gtk-extensions.h>
 #include <eel/eel-glib-extensions.h>
 #include <gdk/gdk.h>
 #include <gdk/gdkkeysyms.h>
@@ -1776,6 +1777,25 @@ get_root_uri_callback (NemoTreeViewDragDest *dest,
 	return nemo_view_get_uri (NEMO_VIEW (view));
 }
 
+// this is confusing... so rename them.
+#define ALLOW_EXPAND FALSE
+#define PREVENT_EXPAND TRUE
+
+static gboolean
+test_expand_row_callback (GtkTreeView *treeview,
+                          GtkTreeIter *iter,
+                          GtkTreePath *path,
+                          gpointer     user_data)
+{
+    NemoListView *view = NEMO_LIST_VIEW (user_data);
+
+    if (eel_gtk_get_treeview_row_text_is_under_pointer (view->details->tree_view)) {
+        return ALLOW_EXPAND;
+    }
+
+    return PREVENT_EXPAND;
+}
+
 static NemoFile *
 get_file_for_path_callback (NemoTreeViewDragDest *dest,
 			    GtkTreePath *path,
@@ -1785,6 +1805,10 @@ get_file_for_path_callback (NemoTreeViewDragDest *dest,
 
     view = NEMO_LIST_VIEW (user_data);
 
+    if (!eel_gtk_get_treeview_row_text_is_under_pointer (view->details->tree_view)) {
+        return NULL;
+    }
+
     return nemo_list_model_file_for_path (view->details->model, path);
 }
 
@@ -2490,7 +2514,7 @@ create_and_set_up_tree_view (NemoListView *view)
 	gtk_binding_entry_remove (binding_set, GDK_KEY_BackSpace, 0);
 
 	view->details->drag_dest =
-		nemo_tree_view_drag_dest_new (view->details->tree_view);
+		nemo_tree_view_drag_dest_new (view->details->tree_view, TRUE);
 
 	g_signal_connect_object (view->details->drag_dest,
 				 "get_root_uri",
@@ -2546,6 +2570,8 @@ create_and_set_up_tree_view (NemoListView *view)
                                  G_CALLBACK (row_collapsed_callback), view, 0);
 	g_signal_connect_object (view->details->tree_view, "row-activated",
                                  G_CALLBACK (row_activated_callback), view, 0);
+    g_signal_connect_object (view->details->tree_view, "test-expand-row",
+                                 G_CALLBACK (test_expand_row_callback), view, 0);
 
     	g_signal_connect_object (view->details->tree_view, "focus_in_event",
 				 G_CALLBACK(focus_in_event_callback), view, 0);

src/nemo-tree-sidebar.c

@@ -1645,7 +1645,7 @@ create_tree (FMTreeView *view)
 	gtk_tree_view_set_headers_visible (view->details->tree_widget, FALSE);
 
 	view->details->drag_dest = 
-		nemo_tree_view_drag_dest_new (view->details->tree_widget);
+		nemo_tree_view_drag_dest_new (view->details->tree_widget, FALSE);
 	g_signal_connect_object (view->details->drag_dest, 
 				 "get_root_uri",
 				 G_CALLBACK (get_root_uri_callback),