[gnome-builder/wip/chergert/layout] layout: add ide_layout_grid_get_nth_column()

[Christian Hergert <chergert src gnome org>]

commit b6046ad8c3c397aa87d63c0a25959e0ab9cf6954
Author: Christian Hergert <chergert redhat com>
Date:   Wed Jul 5 14:34:58 2017 -0700

    layout: add ide_layout_grid_get_nth_column()
    
    This is a convenience function to get a particular column and
    create it if it does not yet exist.

 libide/layout/ide-layout-grid.c |   55 +++++++++++++++++++++++++++++----------
 libide/layout/ide-layout-grid.h |    2 +
 2 files changed, 43 insertions(+), 14 deletions(-)
---
diff --git a/libide/layout/ide-layout-grid.c b/libide/layout/ide-layout-grid.c
index 89a4626..cf54ad5 100644
--- a/libide/layout/ide-layout-grid.c
+++ b/libide/layout/ide-layout-grid.c
@@ -494,25 +494,26 @@ ide_layout_grid_get_current_stack (IdeLayoutGrid *self)
   return NULL;
 }
 
-/*
- * _ide_layout_grid_get_nth_stack:
+/**
+ * ide_layout_grid_get_nth_column:
+ * @self: a #IdeLayoutGrid
+ * @nth: the index of the column, or -1
  *
- * This will get the @nth stack. If it does not yet exist,
- * it will be created.
+ * Gets the @nth column from the grid.
  *
- * If nth == -1, a new stack will be created at index 0.
+ * If @nth is -1, then a new column at the beginning of the
+ * grid is created.
  *
- * If nth >= the number of stacks, a new stack will be created
- * at the end of the grid.
+ * If @nth is >= the number of columns in the grid, then a new
+ * column at the end of the grid is created.
  *
- * Returns: (not nullable) (transfer none): An #IdeLayoutStack.
+ * Returns: (transfer none): An #IdeLayoutGridColumn.
  */
-IdeLayoutStack *
-_ide_layout_grid_get_nth_stack (IdeLayoutGrid *self,
+IdeLayoutGridColumn *
+ide_layout_grid_get_nth_column (IdeLayoutGrid *self,
                                 gint           nth)
 {
-  GtkWidget *column = NULL;
-  IdeLayoutStack *stack;
+  GtkWidget *column;
 
   g_return_val_if_fail (IDE_IS_LAYOUT_GRID (self), NULL);
 
@@ -533,11 +534,37 @@ _ide_layout_grid_get_nth_stack (IdeLayoutGrid *self,
       column = dzl_multi_paned_get_nth_child (DZL_MULTI_PANED (self), nth);
     }
 
-  g_assert (IDE_IS_LAYOUT_GRID_COLUMN (column));
+  g_return_val_if_fail (IDE_IS_LAYOUT_GRID_COLUMN (column), NULL);
+
+  return IDE_LAYOUT_GRID_COLUMN (column);
+}
+
+/*
+ * _ide_layout_grid_get_nth_stack:
+ *
+ * This will get the @nth stack. If it does not yet exist,
+ * it will be created.
+ *
+ * If nth == -1, a new stack will be created at index 0.
+ *
+ * If nth >= the number of stacks, a new stack will be created
+ * at the end of the grid.
+ *
+ * Returns: (not nullable) (transfer none): An #IdeLayoutStack.
+ */
+IdeLayoutStack *
+_ide_layout_grid_get_nth_stack (IdeLayoutGrid *self,
+                                gint           nth)
+{
+  IdeLayoutGridColumn *column;
+  IdeLayoutStack *stack;
+
+  g_return_val_if_fail (IDE_IS_LAYOUT_GRID (self), NULL);
 
+  column = ide_layout_grid_get_nth_column (self, nth);
   stack = ide_layout_grid_column_get_current_stack (IDE_LAYOUT_GRID_COLUMN (column));
 
-  g_assert (IDE_IS_LAYOUT_STACK (stack));
+  g_return_val_if_fail (IDE_IS_LAYOUT_STACK (stack), NULL);
 
   return stack;
 }
diff --git a/libide/layout/ide-layout-grid.h b/libide/layout/ide-layout-grid.h
index 53ba67e..a14d1ac 100644
--- a/libide/layout/ide-layout-grid.h
+++ b/libide/layout/ide-layout-grid.h
@@ -47,6 +47,8 @@ struct _IdeLayoutGridClass
 };
 
 GtkWidget           *ide_layout_grid_new                (void);
+IdeLayoutGridColumn *ide_layout_grid_get_nth_column     (IdeLayoutGrid       *self,
+                                                         gint                 nth);
 IdeLayoutGridColumn *ide_layout_grid_get_current_column (IdeLayoutGrid       *self);
 void                 ide_layout_grid_set_current_column (IdeLayoutGrid       *self,
                                                          IdeLayoutGridColumn *column);