[evolution] Bug 651270 - Allow Drag&Drop to reorder items in Mail Filters dialog

[Milan Crha <mcrha src gnome org>]

commit 0086baed2c239bfd44280eab61f67263912c6647
Author: Milan Crha <mcrha redhat com>
Date:   Wed Dec 6 22:56:19 2017 +0100

    Bug 651270 - Allow Drag&Drop to reorder items in Mail Filters dialog

 src/e-util/e-rule-editor.c |  132 ++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 132 insertions(+), 0 deletions(-)
---
diff --git a/src/e-util/e-rule-editor.c b/src/e-util/e-rule-editor.c
index a87da78..414b809 100644
--- a/src/e-util/e-rule-editor.c
+++ b/src/e-util/e-rule-editor.c
@@ -50,6 +50,7 @@ enum {
 
 struct _ERuleEditorPrivate {
        GtkButton *buttons[BUTTON_LAST];
+       gint drag_index;
 };
 
 G_DEFINE_TYPE (
@@ -612,6 +613,7 @@ static void
 e_rule_editor_init (ERuleEditor *editor)
 {
        editor->priv = E_RULE_EDITOR_GET_PRIVATE (editor);
+       editor->priv->drag_index = -1;
 }
 
 /**
@@ -724,6 +726,121 @@ rule_able_toggled (GtkCellRendererToggle *renderer,
        gtk_tree_path_free (path);
 }
 
+static void
+editor_tree_drag_begin_cb (GtkWidget *widget,
+                          GdkDragContext *context,
+                          gpointer user_data)
+{
+       ERuleEditor *editor = user_data;
+       GtkTreeSelection *selection;
+       cairo_surface_t *surface;
+       GtkTreeModel *model;
+       GtkTreePath *path;
+       GtkTreeIter iter;
+       EFilterRule *rule = NULL;
+
+       g_return_if_fail (editor != NULL);
+
+       selection = gtk_tree_view_get_selection (editor->list);
+       if (!gtk_tree_selection_get_selected (selection, &model, &iter)) {
+               editor->priv->drag_index = -1;
+               return;
+       }
+
+       gtk_tree_model_get (model, &iter, 1, &rule, -1);
+       if (!rule) {
+               editor->priv->drag_index = -1;
+               return;
+       }
+
+       editor->priv->drag_index = e_rule_context_get_rank_rule (editor->context, rule, editor->source);
+
+       path = gtk_tree_model_get_path (model, &iter);
+
+       surface = gtk_tree_view_create_row_drag_icon (editor->list, path);
+       gtk_drag_set_icon_surface (context, surface);
+
+       gtk_tree_path_free (path);
+}
+
+static gboolean
+editor_tree_drag_drop_cb (GtkWidget *widget,
+                         GdkDragContext *context,
+                         gint x,
+                         gint y,
+                         guint time,
+                         gpointer user_data)
+{
+       ERuleEditor *editor = user_data;
+
+       g_return_val_if_fail (editor != NULL, FALSE);
+
+       editor->priv->drag_index = -1;
+
+       return TRUE;
+}
+
+static void
+editor_tree_drag_end_cb (GtkWidget *widget,
+                        GdkDragContext *context,
+                        gpointer user_data)
+{
+       ERuleEditor *editor = user_data;
+
+       g_return_if_fail (editor != NULL);
+
+       editor->priv->drag_index = -1;
+}
+
+static gboolean
+editor_tree_drag_motion_cb (GtkWidget *widget,
+                           GdkDragContext *context,
+                           gint x,
+                           gint y,
+                           guint time,
+                           gpointer user_data)
+{
+       ERuleEditor *editor = user_data;
+       GtkTreeModel *model;
+       GtkTreeIter iter;
+       GtkTreePath *path = NULL;
+       EFilterRule *rule = NULL;
+
+       g_return_val_if_fail (editor != NULL, FALSE);
+
+       if (editor->priv->drag_index == -1 ||
+           !gtk_tree_view_get_dest_row_at_pos (editor->list, x, y, &path, NULL))
+               return FALSE;
+
+       model = gtk_tree_view_get_model (editor->list);
+
+       g_warn_if_fail (gtk_tree_model_get_iter (model, &iter, path));
+
+       gtk_tree_path_free (path);
+
+       gtk_tree_model_get (model, &iter, 1, &rule, -1);
+
+       if (rule) {
+               gint drop_index;
+
+               drop_index = e_rule_context_get_rank_rule (editor->context, rule, editor->source);
+
+               if (drop_index != editor->priv->drag_index && drop_index >= 0) {
+                       editor->current = e_rule_context_find_rank_rule (editor->context, 
editor->priv->drag_index, editor->source);
+                       rule_move (editor, editor->priv->drag_index, drop_index);
+
+                       editor->priv->drag_index = drop_index;
+
+                       /* to update the editor->current */
+                       cursor_changed (NULL, editor);
+               }
+       }
+
+       gdk_drag_status (context, (!rule || editor->priv->drag_index == -1) ? 0 : GDK_ACTION_MOVE, time);
+
+       return TRUE;
+}
+
 void
 e_rule_editor_construct (ERuleEditor *editor,
                          ERuleContext *context,
@@ -731,6 +848,9 @@ e_rule_editor_construct (ERuleEditor *editor,
                          const gchar *source,
                          const gchar *label)
 {
+       const GtkTargetEntry row_targets[] = {
+               { (gchar *) "ERuleEditorRow", GTK_TARGET_SAME_WIDGET, 0 }
+       };
        GtkWidget *widget;
        GtkWidget *action_area;
        GtkWidget *content_area;
@@ -810,4 +930,16 @@ e_rule_editor_construct (ERuleEditor *editor,
                _("_Cancel"), GTK_RESPONSE_CANCEL,
                _("_OK"), GTK_RESPONSE_OK,
                NULL);
+
+       gtk_drag_source_set (GTK_WIDGET (editor->list), GDK_BUTTON1_MASK, row_targets, G_N_ELEMENTS 
(row_targets), GDK_ACTION_MOVE);
+       gtk_drag_dest_set (GTK_WIDGET (editor->list), GTK_DEST_DEFAULT_MOTION, row_targets, G_N_ELEMENTS 
(row_targets), GDK_ACTION_MOVE);
+
+       g_signal_connect (editor->list, "drag-begin",
+               G_CALLBACK (editor_tree_drag_begin_cb), editor);
+       g_signal_connect (editor->list, "drag-drop",
+               G_CALLBACK (editor_tree_drag_drop_cb), editor);
+       g_signal_connect (editor->list, "drag-end",
+               G_CALLBACK (editor_tree_drag_end_cb), editor);
+       g_signal_connect (editor->list, "drag-motion",
+               G_CALLBACK (editor_tree_drag_motion_cb), editor);
 }