[gnome-shell] a11y: add a generic accessible

[Alejandro Piñeiro Iglesias <apinheiro src gnome org>]

commit 5c048403127ca0b4774ac7fd97d5197c38fb1a81
Author: Alejandro Piñeiro <apinheiro igalia com>
Date:   Thu Aug 22 19:55:57 2013 +0200

    a11y: add a generic accessible
    
    Using the same idea that shell-generic-container. It implements
    AtkValue with a dummy implementation based on signals. Javascript
    code would connect to that and returns the proper value.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=648623

 src/Makefile-st.am             |    2 +
 src/st/st-generic-accessible.c |  238 ++++++++++++++++++++++++++++++++++++++++
 src/st/st-generic-accessible.h |   62 +++++++++++
 3 files changed, 302 insertions(+), 0 deletions(-)
---
diff --git a/src/Makefile-st.am b/src/Makefile-st.am
index b828944..7cbdfd8 100644
--- a/src/Makefile-st.am
+++ b/src/Makefile-st.am
@@ -52,6 +52,7 @@ st_source_h =                                 \
        st/st-drawing-area.h                    \
        st/st-entry.h                           \
        st/st-focus-manager.h                   \
+       st/st-generic-accessible.h              \
        st/st-icon.h                            \
        st/st-icon-colors.h                     \
        st/st-im-text.h                         \
@@ -120,6 +121,7 @@ st_source_c =                                       \
        st/st-drawing-area.c                    \
        st/st-entry.c                           \
        st/st-focus-manager.c                   \
+       st/st-generic-accessible.c              \
        st/st-icon.c                            \
        st/st-icon-colors.c                     \
        st/st-im-text.c                         \
diff --git a/src/st/st-generic-accessible.c b/src/st/st-generic-accessible.c
new file mode 100644
index 0000000..e9b9302
--- /dev/null
+++ b/src/st/st-generic-accessible.c
@@ -0,0 +1,238 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+/*
+ * st-generic-accessible.c: generic accessible
+ *
+ * Copyright 2013 Igalia, S.L.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU Lesser General Public License,
+ * version 2.1, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * SECTION:st-generic-accessible
+ * @short_description: An accessible class with signals for
+ * implementing specific Atk interfaces
+ *
+ * #StGenericAccessible is mainly a workaround for the current lack of
+ * of a proper support for GValue at javascript. See bug#703412 for
+ * more information. We implement the accessible interfaces, but proxy
+ * the virtual functions into signals, which gjs can catch.
+ *
+ * #StGenericAccessible is an #StWidgetAccessible
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "st-generic-accessible.h"
+
+static void atk_value_iface_init (AtkValueIface *iface);
+
+G_DEFINE_TYPE_WITH_CODE(StGenericAccessible,
+                        st_generic_accessible,
+                        ST_TYPE_WIDGET_ACCESSIBLE,
+                        G_IMPLEMENT_INTERFACE (ATK_TYPE_VALUE,
+                                               atk_value_iface_init));
+/* Signals */
+enum
+{
+  GET_CURRENT_VALUE,
+  GET_MAXIMUM_VALUE,
+  GET_MINIMUM_VALUE,
+  SET_CURRENT_VALUE,
+  GET_MINIMUM_INCREMENT,
+  LAST_SIGNAL
+};
+
+static guint st_generic_accessible_signals [LAST_SIGNAL] = { 0 };
+
+static void
+st_generic_accessible_init (StGenericAccessible *accessible)
+{
+}
+
+static void
+st_generic_accessible_class_init (StGenericAccessibleClass *klass)
+{
+  /**
+   * StGenericAccessible::get-current-value:
+   * @self: the #StGenericAccessible
+   *
+   * Emitted when atk_value_get_current_value() is called on
+   * @self. Right now we only care about doubles, so the value is
+   * directly returned by the signal.
+   *
+   * Return value: value of the current element.
+   */
+  st_generic_accessible_signals[GET_CURRENT_VALUE] =
+    g_signal_new ("get-current-value",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST,
+                  0,
+                  NULL, NULL, NULL,
+                  G_TYPE_DOUBLE, 0);
+
+  /**
+   * StGenericAccessible::get-maximum-value:
+   * @self: the #StGenericAccessible
+   *
+   * Emitted when atk_value_get_maximum_value() is called on
+   * @self. Right now we only care about doubles, so the value is
+   * directly returned by the signal.
+   *
+   * Return value: maximum value of the accessible.
+   */
+  st_generic_accessible_signals[GET_MAXIMUM_VALUE] =
+    g_signal_new ("get-maximum-value",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST,
+                  0,
+                  NULL, NULL, NULL,
+                  G_TYPE_DOUBLE, 0);
+
+  /**
+   * StGenericAccessible::get-minimum-value:
+   * @self: the #StGenericAccessible
+   *
+   * Emitted when atk_value_get_current_value() is called on
+   * @self. Right now we only care about doubles, so the value is
+   * directly returned by the signal.
+   *
+   * Return value: minimum value of the accessible.
+   */
+  st_generic_accessible_signals[GET_MINIMUM_VALUE] =
+    g_signal_new ("get-minimum-value",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST,
+                  0,
+                  NULL, NULL, NULL,
+                  G_TYPE_DOUBLE, 0);
+
+  /**
+   * StGenericAccessible::get-minimum-increment:
+   * @self: the #StGenericAccessible
+   *
+   * Emitted when atk_value_get_minimum_increment() is called on
+   * @self. Right now we only care about doubles, so the value is
+   * directly returned by the signal.
+   *
+   * Return value: value of the current element.
+   */
+  st_generic_accessible_signals[GET_MINIMUM_INCREMENT] =
+    g_signal_new ("get-minimum-increment",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST,
+                  0,
+                  NULL, NULL, NULL,
+                  G_TYPE_DOUBLE, 0);
+
+  /**
+   * StGenericAccessible::set-current-value:
+   * @self: the #StGenericAccessible
+   * @new_value: the new value for the accessible
+   *
+   * Emitted when atk_value_set_current_value() is called on
+   * @self. Right now we only care about doubles, so the value is
+   * directly returned by the signal.
+   *
+   * Return value: value of the current element.
+   */
+  st_generic_accessible_signals[SET_CURRENT_VALUE] =
+    g_signal_new ("set-current-value",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST,
+                  0,
+                  NULL, NULL, NULL,
+                  G_TYPE_NONE, 1, G_TYPE_DOUBLE);
+
+}
+
+static void
+st_generic_accessible_get_current_value (AtkValue *obj,
+                                         GValue   *value)
+{
+  gdouble current_value = 0;
+
+  g_value_init (value, G_TYPE_DOUBLE);
+  g_signal_emit (G_OBJECT (obj), st_generic_accessible_signals[GET_CURRENT_VALUE], 0, &current_value);
+  g_value_set_double (value, current_value);
+}
+
+static void
+st_generic_accessible_get_maximum_value (AtkValue *obj,
+                                         GValue   *value)
+{
+  gdouble current_value = 0;
+
+  g_value_init (value, G_TYPE_DOUBLE);
+  g_signal_emit (G_OBJECT (obj), st_generic_accessible_signals[GET_MAXIMUM_VALUE], 0, &current_value);
+  g_value_set_double (value, current_value);
+}
+
+static void
+st_generic_accessible_get_minimum_value (AtkValue *obj,
+                                         GValue   *value)
+{
+  gdouble current_value = 0;
+
+  g_value_init (value, G_TYPE_DOUBLE);
+  g_signal_emit (G_OBJECT (obj), st_generic_accessible_signals[GET_MINIMUM_VALUE], 0, &current_value);
+  g_value_set_double (value, current_value);
+}
+
+static void
+st_generic_accessible_get_minimum_increment (AtkValue *obj,
+                                             GValue   *value)
+{
+  gdouble current_value = 0;
+
+  g_value_init (value, G_TYPE_DOUBLE);
+  g_signal_emit (G_OBJECT (obj), st_generic_accessible_signals[GET_MINIMUM_INCREMENT], 0, &current_value);
+  g_value_set_double (value, current_value);
+}
+
+static gboolean
+st_generic_accessible_set_current_value (AtkValue *obj,
+                                         const GValue *value)
+{
+  gdouble current_value = 0;
+
+  current_value = g_value_get_double (value);
+  g_signal_emit (G_OBJECT (obj), st_generic_accessible_signals[SET_CURRENT_VALUE], 0, current_value);
+
+  return TRUE; // we assume that the value was properly set
+}
+
+static void
+atk_value_iface_init (AtkValueIface *iface)
+{
+  iface->get_current_value = st_generic_accessible_get_current_value;
+  iface->get_maximum_value = st_generic_accessible_get_maximum_value;
+  iface->get_minimum_value = st_generic_accessible_get_minimum_value;
+  iface->get_minimum_increment = st_generic_accessible_get_minimum_increment;
+  iface->set_current_value = st_generic_accessible_set_current_value;
+}
+
+AtkObject*
+st_generic_accessible_new_for_actor (ClutterActor *actor)
+{
+  AtkObject *accessible = NULL;
+
+  g_return_val_if_fail (CLUTTER_IS_ACTOR (actor), NULL);
+
+  accessible = ATK_OBJECT (g_object_new (ST_TYPE_GENERIC_ACCESSIBLE,
+                                         NULL));
+  atk_object_initialize (accessible, actor);
+
+  return accessible;
+}
diff --git a/src/st/st-generic-accessible.h b/src/st/st-generic-accessible.h
new file mode 100644
index 0000000..99a6a71
--- /dev/null
+++ b/src/st/st-generic-accessible.h
@@ -0,0 +1,62 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+/*
+ * st-generic-accessible.h: generic accessible
+ *
+ * Copyright 2013 Igalia, S.L.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU Lesser General Public License,
+ * version 2.1, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#if !defined(ST_H_INSIDE) && !defined(ST_COMPILATION)
+#error "Only <st/st.h> can be included directly.h"
+#endif
+
+#ifndef __ST_GENERIC_ACCESSIBLE_H__
+#define __ST_GENERIC_ACCESSIBLE_H__
+
+#include <clutter/clutter.h>
+#include <st/st-widget-accessible.h>
+
+G_BEGIN_DECLS
+
+#define ST_TYPE_GENERIC_ACCESSIBLE                 (st_generic_accessible_get_type ())
+#define ST_GENERIC_ACCESSIBLE(obj)                 (G_TYPE_CHECK_INSTANCE_CAST ((obj), 
ST_TYPE_GENERIC_ACCESSIBLE, StGenericAccessible))
+#define ST_GENERIC_ACCESSIBLE_CLASS(klass)         (G_TYPE_CHECK_CLASS_CAST ((klass), 
ST_TYPE_GENERIC_ACCESSIBLE, StGenericAccessibleClass))
+#define ST_IS_GENERIC_ACCESSIBLE(obj)              (G_TYPE_CHECK_INSTANCE_TYPE ((obj), 
ST_TYPE_GENERIC_ACCESSIBLE))
+#define ST_IS_GENERIC_ACCESSIBLE_CLASS(klass)      (G_TYPE_CHECK_CLASS_TYPE ((klass), 
ST_TYPE_GENERIC_ACCESSIBLE))
+#define ST_GENERIC_ACCESSIBLE_GET_CLASS(obj)       (G_TYPE_INSTANCE_GET_CLASS ((obj), 
ST_TYPE_GENERIC_ACCESSIBLE, StGenericAccessibleClass))
+
+typedef struct _StGenericAccessible        StGenericAccessible;
+typedef struct _StGenericAccessibleClass   StGenericAccessibleClass;
+
+typedef struct _StGenericAccessiblePrivate StGenericAccessiblePrivate;
+
+struct _StGenericAccessible
+{
+    StWidgetAccessible parent;
+
+    StGenericAccessiblePrivate *priv;
+};
+
+struct _StGenericAccessibleClass
+{
+    StWidgetAccessibleClass parent_class;
+};
+
+GType       st_generic_accessible_get_type         (void) G_GNUC_CONST;
+
+AtkObject*  st_generic_accessible_new_for_actor (ClutterActor *actor);
+
+G_END_DECLS
+
+#endif /* __ST_GENERIC_ACCESSIBLE_H__ */