From 0e176199fcc05cf0eac3d43e0e4d9e679a74960c Mon Sep 17 00:00:00 2001
From: Dave Davenport <qball@gmpclient.org>
Date: Mon, 17 Oct 2016 18:21:03 +0200
Subject: [PATCH] Fix some possible null pointer dereference. (clang-check)

---
 include/widgets/widget.h  | 14 ++++++++++++++
 source/widgets/box.c      |  1 +
 source/widgets/listview.c | 10 +++++-----
 source/widgets/widget.c   | 14 ++++++++++++++
 4 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/include/widgets/widget.h b/include/widgets/widget.h
index 8edc3de5..2b871ec1 100644
--- a/include/widgets/widget.h
+++ b/include/widgets/widget.h
@@ -108,6 +108,20 @@ int widget_get_height ( widget *widget );
  */
 int widget_get_width ( widget *widget );
 
+/**
+ * @param widget The widget handle
+ *
+ * @returns the y postion of the widget relative to its parent.
+ */
+int widget_get_y_pos ( widget *widget );
+
+/**
+ * @param widget The widget handle
+ *
+ * @returns the x postion of the widget relative to its parent.
+ */
+int widget_get_x_pos ( widget *widget );
+
 /**
  * @param widget The widget handle
  *
diff --git a/source/widgets/box.c b/source/widgets/box.c
index 8aec12b1..6f5b12de 100644
--- a/source/widgets/box.c
+++ b/source/widgets/box.c
@@ -208,6 +208,7 @@ static void box_free ( widget *wid )
 
 void box_add ( box *box, widget *child, gboolean expand, gboolean end )
 {
+    if ( box == NULL ) return;
     child->expand = expand;
     child->end    = end;
     child->parent = WIDGET ( box );
diff --git a/source/widgets/listview.c b/source/widgets/listview.c
index a5184a18..055be2f6 100644
--- a/source/widgets/listview.c
+++ b/source/widgets/listview.c
@@ -151,7 +151,7 @@ static void listview_draw ( widget *wid, cairo_t *draw )
             unsigned int width = lv->widget.w - lv->padding * ( lv->cur_columns - 1 );
             if ( widget_enabled ( WIDGET ( lv->scrollbar ) ) ) {
                 width -= lv->padding;
-                width -= lv->scrollbar->widget.w;
+                width -= widget_get_width ( WIDGET ( lv->scrollbar ) );
             }
             unsigned int element_width = ( width ) / lv->cur_columns;
             for ( unsigned int i = 0; i < max; i++ ) {
@@ -237,8 +237,8 @@ static void listview_resize ( widget *wid, short w, short h )
     lv->max_rows     = ( lv->padding + lv->widget.h ) / ( lv->element_height + lv->padding );
     lv->max_elements = lv->max_rows * lv->menu_columns;
 
-    widget_move ( WIDGET ( lv->scrollbar ), lv->widget.w - lv->scrollbar->widget.w, 0 );
-    widget_resize (  WIDGET ( lv->scrollbar ), lv->scrollbar->widget.w, h );
+    widget_move ( WIDGET ( lv->scrollbar ), lv->widget.w - widget_get_width ( WIDGET (lv->scrollbar ) ), 0 );
+    widget_resize (  WIDGET ( lv->scrollbar ), widget_get_width ( WIDGET ( lv->scrollbar ) ), h );
 
     listview_recompute_elements ( lv );
     widget_queue_redraw ( wid );
@@ -260,8 +260,8 @@ static gboolean listview_clicked ( widget *wid, xcb_button_press_event_t *xce, G
     if ( widget_enabled ( WIDGET ( lv->scrollbar ) ) && widget_intersect ( WIDGET ( lv->scrollbar ), xce->event_x, xce->event_y ) ) {
         // Forward to handler of scrollbar.
         xcb_button_press_event_t xce2 = *xce;
-        xce->event_x -= lv->scrollbar->widget.x;
-        xce->event_y -= lv->scrollbar->widget.y;
+        xce->event_x -= widget_get_x_pos ( WIDGET ( lv->scrollbar ) );
+        xce->event_y -= widget_get_y_pos ( WIDGET ( lv->scrollbar ) );
         return widget_clicked ( WIDGET ( lv->scrollbar ), &xce2 );
     }
     // Handle the boxes.
diff --git a/source/widgets/widget.c b/source/widgets/widget.c
index 916ce61c..48642cb7 100644
--- a/source/widgets/widget.c
+++ b/source/widgets/widget.c
@@ -93,6 +93,20 @@ int widget_get_width ( widget *widget )
     }
     return 0;
 }
+int widget_get_x_pos ( widget *widget )
+{
+    if ( widget ) {
+        return widget->x;
+    }
+    return 0;
+}
+int widget_get_y_pos ( widget *widget )
+{
+    if ( widget ) {
+        return widget->y;
+    }
+    return 0;
+}
 
 void widget_update ( widget *widget )
 {