[gtk/wip/ebassi/constraint-layout: 3/5] Assign a GtkConstraintSolver to each GtkRoot

[Emmanuele Bassi <ebassi src gnome org>]

commit bb739da8ff97c958fffd50948cd96eca64828987
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Tue Apr 9 14:20:54 2019 +0100

    Assign a GtkConstraintSolver to each GtkRoot
    
    Constraints need to work across different parents, so it's better to
    have a single constraint solver per top level.

 gtk/gtkroot.c        | 18 ++++++++++++++++++
 gtk/gtkrootprivate.h | 11 +++++++++--
 2 files changed, 27 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtkroot.c b/gtk/gtkroot.c
index 249d7405b1..c93a065f16 100644
--- a/gtk/gtkroot.c
+++ b/gtk/gtkroot.c
@@ -61,12 +61,19 @@ gtk_root_default_get_surface_transform (GtkRoot *self,
   *y = 0;
 }
 
+static GtkConstraintSolver *
+gtk_root_default_get_constraint_solver (GtkRoot *self)
+{
+  return NULL;
+}
+
 static void
 gtk_root_default_init (GtkRootInterface *iface)
 {
   iface->get_display = gtk_root_default_get_display;
   iface->get_renderer = gtk_root_default_get_renderer;
   iface->get_surface_transform = gtk_root_default_get_surface_transform;
+  iface->get_constraint_solver = gtk_root_default_get_constraint_solver;
 
   g_object_interface_install_property (iface,
       g_param_spec_object ("focus-widget",
@@ -113,6 +120,17 @@ gtk_root_get_surface_transform (GtkRoot *self,
   return iface->get_surface_transform (self, x, y);
 }
 
+GtkConstraintSolver *
+gtk_root_get_constraint_solver (GtkRoot *self)
+{
+  GtkRootInterface *iface;
+
+  g_return_val_if_fail (GTK_IS_ROOT (self), NULL);
+
+  iface = GTK_ROOT_GET_IFACE (self);
+  return iface->get_constraint_solver (self);
+}
+
 /**
  * gtk_root_get_for_surface:
  * @surface: a #GdkSurface
diff --git a/gtk/gtkrootprivate.h b/gtk/gtkrootprivate.h
index ecdabe4a25..62c1471121 100644
--- a/gtk/gtkrootprivate.h
+++ b/gtk/gtkrootprivate.h
@@ -3,6 +3,8 @@
 
 #include "gtkroot.h"
 
+#include "gtkconstraintsolverprivate.h"
+
 G_BEGIN_DECLS
 
 /*
@@ -19,17 +21,22 @@ struct _GtkRootInterface
   GdkDisplay *          (* get_display)                 (GtkRoot                *self);
   GskRenderer *         (* get_renderer)                (GtkRoot                *self);
 
-  void                  (* get_surface_transform)       (GtkRoot                *root,
+  void                  (* get_surface_transform)       (GtkRoot                *self,
                                                          int                    *x,
                                                          int                    *y);
+
+  GtkConstraintSolver * (* get_constraint_solver)       (GtkRoot                *self);
 };
 
-GdkDisplay *            gtk_root_get_display            (GtkRoot                *root);
+GdkDisplay *            gtk_root_get_display            (GtkRoot                *self);
 GskRenderer *           gtk_root_get_renderer           (GtkRoot                *self);
 
 void                    gtk_root_get_surface_transform  (GtkRoot                *self,
                                                          int                    *x,
                                                          int                    *y);
+
+GtkConstraintSolver *   gtk_root_get_constraint_solver  (GtkRoot                *self);
+
 enum {
   GTK_ROOT_PROP_FOCUS_WIDGET,
   GTK_ROOT_NUM_PROPERTIES