[gtk/a11y/atspi] accessible: Add gtk_accessible_get_platform_state

[Matthias Clasen <matthiasc src gnome org>]

commit ade9e4b82af90666711474b00b2342b1380937f1
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Oct 12 19:00:03 2020 -0400

    accessible: Add gtk_accessible_get_platform_state
    
    As a companion to go with the platform_change api,
    add a gtk_accessible_get_platform_state() function
    that can be used by backends to get the platform
    state.
    
    This is in preparation for making entries inherit
    their focus states from the text widget within.

 gtk/gtkaccessible.c        | 17 +++++++++++++++++
 gtk/gtkaccessibleprivate.h |  9 +++++++--
 gtk/gtkatcontextprivate.h  |  9 +++++++--
 gtk/gtkwidget.c            | 16 ++++++++++++++++
 4 files changed, 47 insertions(+), 4 deletions(-)
---
diff --git a/gtk/gtkaccessible.c b/gtk/gtkaccessible.c
index 49186ed0ff..6215e032d8 100644
--- a/gtk/gtkaccessible.c
+++ b/gtk/gtkaccessible.c
@@ -643,6 +643,16 @@ gtk_accessible_platform_changed (GtkAccessible               *self,
                                  GtkAccessiblePlatformChange  change)
 {
   GtkATContext *context = gtk_accessible_get_at_context (self);
+
+  /* propagate changes up from ignored widgets */
+  if (gtk_accessible_get_accessible_role (self) == GTK_ACCESSIBLE_ROLE_NONE)
+    {
+      if (gtk_widget_get_parent (GTK_WIDGET (self)) == NULL)
+        return;
+
+      context = gtk_accessible_get_at_context (GTK_ACCESSIBLE (gtk_widget_get_parent (GTK_WIDGET (self))));
+    }
+
   if (context == NULL)
     return;
 
@@ -650,6 +660,13 @@ gtk_accessible_platform_changed (GtkAccessible               *self,
   gtk_at_context_update (context);
 }
 
+gboolean
+gtk_accessible_get_platform_state (GtkAccessible              *self,
+                                   GtkAccessiblePlatformState  state)
+{
+  return GTK_ACCESSIBLE_GET_IFACE (self)->get_platform_state (self, state);
+}
+
 gboolean
 gtk_accessible_should_present (GtkAccessible *self)
 {
diff --git a/gtk/gtkaccessibleprivate.h b/gtk/gtkaccessibleprivate.h
index ae4847f39c..4d1f458fb8 100644
--- a/gtk/gtkaccessibleprivate.h
+++ b/gtk/gtkaccessibleprivate.h
@@ -30,6 +30,9 @@ struct _GtkAccessibleInterface
   GTypeInterface g_iface;
 
   GtkATContext *        (* get_at_context)      (GtkAccessible *self);
+
+  gboolean              (* get_platform_state)  (GtkAccessible              *self,
+                                                 GtkAccessiblePlatformState  state);
 };
 
 GtkATContext *  gtk_accessible_get_at_context   (GtkAccessible *self);
@@ -37,8 +40,10 @@ GtkATContext *  gtk_accessible_get_at_context   (GtkAccessible *self);
 const char *    gtk_accessible_role_to_name     (GtkAccessibleRole  role,
                                                  const char        *domain);
 
-void            gtk_accessible_platform_changed (GtkAccessible               *self,
-                                                 GtkAccessiblePlatformChange  change);
+void            gtk_accessible_platform_changed (GtkAccessible                *self,
+                                                 GtkAccessiblePlatformChange   change);
+gboolean        gtk_accessible_get_platform_state (GtkAccessible              *self,
+                                                   GtkAccessiblePlatformState  state);
 
 gboolean        gtk_accessible_should_present   (GtkAccessible     *self);
 
diff --git a/gtk/gtkatcontextprivate.h b/gtk/gtkatcontextprivate.h
index fb396c8ccc..4fec1444c8 100644
--- a/gtk/gtkatcontextprivate.h
+++ b/gtk/gtkatcontextprivate.h
@@ -81,8 +81,13 @@ typedef enum {
 } GtkAccessibleStateChange;
 
 typedef enum {
-  GTK_ACCESSIBLE_PLATFORM_CHANGE_FOCUSABLE = 1 << 0,
-  GTK_ACCESSIBLE_PLATFORM_CHANGE_FOCUSED   = 1 << 1,
+  GTK_ACCESSIBLE_PLATFORM_STATE_FOCUSABLE,
+  GTK_ACCESSIBLE_PLATFORM_STATE_FOCUSED,
+} GtkAccessiblePlatformState;
+
+typedef enum {
+  GTK_ACCESSIBLE_PLATFORM_CHANGE_FOCUSABLE = 1 << GTK_ACCESSIBLE_PLATFORM_STATE_FOCUSABLE,
+  GTK_ACCESSIBLE_PLATFORM_CHANGE_FOCUSED   = 1 << GTK_ACCESSIBLE_PLATFORM_STATE_FOCUSED,
 } GtkAccessiblePlatformChange;
 
 struct _GtkATContext
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index fea2da5c3f..acaaf9251a 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -8124,10 +8124,26 @@ gtk_widget_accessible_get_at_context (GtkAccessible *accessible)
   return priv->at_context;
 }
 
+static gboolean
+gtk_widget_accessible_get_platform_state (GtkAccessible              *self,
+                                          GtkAccessiblePlatformState  state)
+{
+  switch (state)
+    {
+    case GTK_ACCESSIBLE_PLATFORM_STATE_FOCUSABLE:
+      return gtk_widget_get_focusable (GTK_WIDGET (self));
+    case GTK_ACCESSIBLE_PLATFORM_STATE_FOCUSED:
+      return gtk_widget_has_focus (GTK_WIDGET (self));
+    default:
+      g_assert_not_reached ();
+    }
+}
+
 static void
 gtk_widget_accessible_interface_init (GtkAccessibleInterface *iface)
 {
   iface->get_at_context = gtk_widget_accessible_get_at_context;
+  iface->get_platform_state = gtk_widget_accessible_get_platform_state;
 }
 
 /*