shell/platform/linux/fl_accessible_node.cc - external/github.com/flutter/engine - Git at Google

 // Copyright 2013 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #include "flutter/shell/platform/linux/fl_accessible_node.h"
 #include "flutter/shell/platform/linux/fl_engine_private.h"

 // Maps Flutter semantics flags to ATK flags.
 static struct {
   AtkStateType state;
   FlutterSemanticsFlag flag;
   gboolean invert;
 } flag_mapping[] = {
     {ATK_STATE_SHOWING, kFlutterSemanticsFlagIsObscured, TRUE},
     {ATK_STATE_VISIBLE, kFlutterSemanticsFlagIsHidden, TRUE},
     {ATK_STATE_CHECKABLE, kFlutterSemanticsFlagHasCheckedState, FALSE},
     {ATK_STATE_FOCUSABLE, kFlutterSemanticsFlagIsFocusable, FALSE},
     {ATK_STATE_FOCUSED, kFlutterSemanticsFlagIsFocused, FALSE},
     {ATK_STATE_CHECKED, kFlutterSemanticsFlagIsChecked, FALSE},
     {ATK_STATE_SELECTED, kFlutterSemanticsFlagIsSelected, FALSE},
     {ATK_STATE_ENABLED, kFlutterSemanticsFlagIsEnabled, FALSE},
     {ATK_STATE_READ_ONLY, kFlutterSemanticsFlagIsReadOnly, FALSE},
     {ATK_STATE_INVALID, static_cast<FlutterSemanticsFlag>(0), FALSE},
 };

 // Maps Flutter semantics actions to ATK actions.
 typedef struct {
   FlutterSemanticsAction action;
   const gchar* name;
 } ActionData;
 static ActionData action_mapping[] = {
     {kFlutterSemanticsActionTap, "Tap"},
     {kFlutterSemanticsActionLongPress, "LongPress"},
     {kFlutterSemanticsActionScrollLeft, "ScrollLeft"},
     {kFlutterSemanticsActionScrollRight, "ScrollRight"},
     {kFlutterSemanticsActionScrollUp, "ScrollUp"},
     {kFlutterSemanticsActionScrollDown, "ScrollDown"},
     {kFlutterSemanticsActionIncrease, "Increase"},
     {kFlutterSemanticsActionDecrease, "Decrease"},
     {kFlutterSemanticsActionShowOnScreen, "ShowOnScreen"},
     {kFlutterSemanticsActionMoveCursorForwardByCharacter,
      "MoveCursorForwardByCharacter"},
     {kFlutterSemanticsActionMoveCursorBackwardByCharacter,
      "MoveCursorBackwardByCharacter"},
     {kFlutterSemanticsActionSetSelection, "SetSelection"},
     {kFlutterSemanticsActionCopy, "Copy"},
     {kFlutterSemanticsActionCut, "Cut"},
     {kFlutterSemanticsActionPaste, "Paste"},
     {kFlutterSemanticsActionDidGainAccessibilityFocus,
      "DidGainAccessibilityFocus"},
     {kFlutterSemanticsActionDidLoseAccessibilityFocus,
      "DidLoseAccessibilityFocus"},
     {kFlutterSemanticsActionCustomAction, "CustomAction"},
     {kFlutterSemanticsActionDismiss, "Dismiss"},
     {kFlutterSemanticsActionMoveCursorForwardByWord, "MoveCursorForwardByWord"},
     {kFlutterSemanticsActionMoveCursorBackwardByWord,
      "MoveCursorBackwardByWord"},
     {static_cast<FlutterSemanticsAction>(0), nullptr}};

 struct _FlAccessibleNode {
   AtkObject parent_instance;

   // Weak reference to the engine this node is created for.
   FlEngine* engine;

   // Weak reference to the parent node of this one or %NULL.
   AtkObject* parent;

   int32_t id;
   gchar* name;
   gint x, y, width, height;
   GPtrArray* actions;
   gsize actions_length;
   GPtrArray* children;
   FlutterSemanticsFlag flags;
 };

 static void fl_accessible_node_component_interface_init(
     AtkComponentIface* iface);
 static void fl_accessible_node_action_interface_init(AtkActionIface* iface);
 static void fl_accessible_node_text_interface_init(AtkTextIface* iface);

 G_DEFINE_TYPE_WITH_CODE(
     FlAccessibleNode,
     fl_accessible_node,
     ATK_TYPE_OBJECT,
     G_IMPLEMENT_INTERFACE(ATK_TYPE_COMPONENT,
                           fl_accessible_node_component_interface_init)
         G_IMPLEMENT_INTERFACE(ATK_TYPE_ACTION,
                               fl_accessible_node_action_interface_init)
             G_IMPLEMENT_INTERFACE(ATK_TYPE_TEXT,
                                   fl_accessible_node_text_interface_init))

 // Returns TRUE if [flag] has changed between [old_flags] and [flags].
 static gboolean flag_is_changed(FlutterSemanticsFlag old_flags,
                                 FlutterSemanticsFlag flags,
                                 FlutterSemanticsFlag flag) {
   return (old_flags & flag) != (flags & flag);
 }

 // Returns TRUE if [flag] is set in [flags].
 static gboolean has_flag(FlutterSemanticsFlag flags,
                          FlutterSemanticsFlag flag) {
   return (flags & flag) != 0;
 }

 // Returns TRUE if [action] is set in [actions].
 static gboolean has_action(FlutterSemanticsAction actions,
                            FlutterSemanticsAction action) {
   return (actions & action) != 0;
 }

 // Gets the nth action.
 static ActionData* get_action(FlAccessibleNode* self, gint index) {
   if (index < 0 || static_cast<guint>(index) >= self->actions->len)
     return nullptr;
   return static_cast<ActionData*>(g_ptr_array_index(self->actions, index));
 }

 static void fl_accessible_node_dispose(GObject* object) {
   FlAccessibleNode* self = FL_ACCESSIBLE_NODE(object);

   if (self->engine != nullptr) {
     g_object_remove_weak_pointer(G_OBJECT(self),
                                  reinterpret_cast<gpointer*>(&(self->engine)));
     self->engine = nullptr;
   }
   if (self->parent != nullptr) {
     g_object_remove_weak_pointer(G_OBJECT(self),
                                  reinterpret_cast<gpointer*>(&(self->parent)));
     self->parent = nullptr;
   }
   g_clear_pointer(&self->name, g_free);
   g_clear_pointer(&self->actions, g_ptr_array_unref);
   g_clear_pointer(&self->children, g_ptr_array_unref);

   G_OBJECT_CLASS(fl_accessible_node_parent_class)->dispose(object);
 }

 // Implements AtkObject::get_name.
 static const gchar* fl_accessible_node_get_name(AtkObject* accessible) {
   FlAccessibleNode* self = FL_ACCESSIBLE_NODE(accessible);
   return self->name;
 }

 // Implements AtkObject::get_parent.
 static AtkObject* fl_accessible_node_get_parent(AtkObject* accessible) {
   FlAccessibleNode* self = FL_ACCESSIBLE_NODE(accessible);
   return self->parent;
 }

 // Implements AtkObject::get_n_children.
 static gint fl_accessible_node_get_n_children(AtkObject* accessible) {
   FlAccessibleNode* self = FL_ACCESSIBLE_NODE(accessible);
   return self->children->len;
 }

 // Implements AtkObject::ref_child.
 static AtkObject* fl_accessible_node_ref_child(AtkObject* accessible, gint i) {
   FlAccessibleNode* self = FL_ACCESSIBLE_NODE(accessible);

   if (i < 0 || static_cast<guint>(i) >= self->children->len) {
     return nullptr;
   }

   return ATK_OBJECT(g_object_ref(g_ptr_array_index(self->children, i)));
 }

 // Implements AtkObject::get_role.
 static AtkRole fl_accessible_node_get_role(AtkObject* accessible) {
   FlAccessibleNode* self = FL_ACCESSIBLE_NODE(accessible);
   if ((self->flags & kFlutterSemanticsFlagIsButton) != 0) {
     return ATK_ROLE_PUSH_BUTTON;
   }
   if ((self->flags & kFlutterSemanticsFlagIsTextField) != 0) {
     return ATK_ROLE_TEXT;
   }
   if ((self->flags & kFlutterSemanticsFlagIsHeader) != 0) {
     return ATK_ROLE_HEADER;
   }
   if ((self->flags & kFlutterSemanticsFlagIsLink) != 0) {
     return ATK_ROLE_LINK;
   }
   if ((self->flags & kFlutterSemanticsFlagIsImage) != 0) {
     return ATK_ROLE_IMAGE;
   }

   return ATK_ROLE_FRAME;
 }

 // Implements AtkObject::ref_state_set.
 static AtkStateSet* fl_accessible_node_ref_state_set(AtkObject* accessible) {
   FlAccessibleNode* self = FL_ACCESSIBLE_NODE(accessible);

   AtkStateSet* state_set = atk_state_set_new();

   for (int i = 0; flag_mapping[i].state != ATK_STATE_INVALID; i++) {
     gboolean enabled = has_flag(self->flags, flag_mapping[i].flag);
     if (flag_mapping[i].invert) {
       enabled = !enabled;
     }
     if (enabled) {
       atk_state_set_add_state(state_set, flag_mapping[i].state);
     }
   }

   return state_set;
 }

 // Implements AtkComponent::get_extents.
 static void fl_accessible_node_get_extents(AtkComponent* component,
                                            gint* x,
                                            gint* y,
                                            gint* width,
                                            gint* height,
                                            AtkCoordType coord_type) {
   FlAccessibleNode* self = FL_ACCESSIBLE_NODE(component);

   *x = 0;
   *y = 0;
   if (self->parent != nullptr) {
     atk_component_get_extents(ATK_COMPONENT(self->parent), x, y, nullptr,
                               nullptr, coord_type);
   }

   *x += self->x;
   *y += self->y;
   *width = self->width;
   *height = self->height;
 }

 // Implements AtkComponent::get_layer.
 static AtkLayer fl_accessible_node_get_layer(AtkComponent* component) {
   return ATK_LAYER_WIDGET;
 }

 // Implements AtkAction::do_action.
 static gboolean fl_accessible_node_do_action(AtkAction* action, gint i) {
   FlAccessibleNode* self = FL_ACCESSIBLE_NODE(action);

   if (self->engine == nullptr) {
     return FALSE;
   }

   ActionData* data = get_action(self, i);
   if (data == nullptr) {
     return FALSE;
   }

   fl_engine_dispatch_semantics_action(self->engine, self->id, data->action,
                                       nullptr);
   return TRUE;
 }

 // Implements AtkAction::get_n_actions.
 static gint fl_accessible_node_get_n_actions(AtkAction* action) {
   FlAccessibleNode* self = FL_ACCESSIBLE_NODE(action);
   return self->actions->len;
 }

 // Implements AtkAction::get_name.
 static const gchar* fl_accessible_node_get_name(AtkAction* action, gint i) {
   FlAccessibleNode* self = FL_ACCESSIBLE_NODE(action);

   ActionData* data = get_action(self, i);
   if (data == nullptr) {
     return nullptr;
   }

   return data->name;
 }

 // Implements AtkText::get_text.
 static gchar* fl_accessible_node_get_text(AtkText* text,
                                           gint start_offset,
                                           gint end_offset) {
   return nullptr;
 }

 static void fl_accessible_node_class_init(FlAccessibleNodeClass* klass) {
   G_OBJECT_CLASS(klass)->dispose = fl_accessible_node_dispose;
   ATK_OBJECT_CLASS(klass)->get_name = fl_accessible_node_get_name;
   ATK_OBJECT_CLASS(klass)->get_parent = fl_accessible_node_get_parent;
   ATK_OBJECT_CLASS(klass)->get_n_children = fl_accessible_node_get_n_children;
   ATK_OBJECT_CLASS(klass)->ref_child = fl_accessible_node_ref_child;
   ATK_OBJECT_CLASS(klass)->get_role = fl_accessible_node_get_role;
   ATK_OBJECT_CLASS(klass)->ref_state_set = fl_accessible_node_ref_state_set;
 }

 static void fl_accessible_node_component_interface_init(
     AtkComponentIface* iface) {
   iface->get_extents = fl_accessible_node_get_extents;
   iface->get_layer = fl_accessible_node_get_layer;
 }

 static void fl_accessible_node_action_interface_init(AtkActionIface* iface) {
   iface->do_action = fl_accessible_node_do_action;
   iface->get_n_actions = fl_accessible_node_get_n_actions;
   iface->get_name = fl_accessible_node_get_name;
 }

 static void fl_accessible_node_text_interface_init(AtkTextIface* iface) {
   iface->get_text = fl_accessible_node_get_text;
 }

 static void fl_accessible_node_init(FlAccessibleNode* self) {
   self->actions = g_ptr_array_new();
   self->children = g_ptr_array_new_with_free_func(g_object_unref);
 }

 FlAccessibleNode* fl_accessible_node_new(FlEngine* engine, int32_t id) {
   FlAccessibleNode* self =
       FL_ACCESSIBLE_NODE(g_object_new(fl_accessible_node_get_type(), nullptr));
   self->engine = engine;
   g_object_add_weak_pointer(G_OBJECT(self),
                             reinterpret_cast<gpointer*>(&(self->engine)));
   self->id = id;
   return self;
 }

 void fl_accessible_node_set_parent(FlAccessibleNode* self, AtkObject* parent) {
   g_return_if_fail(FL_IS_ACCESSIBLE_NODE(self));
   self->parent = parent;
   g_object_add_weak_pointer(G_OBJECT(self),
                             reinterpret_cast<gpointer*>(&(self->parent)));
 }

 void fl_accessible_node_set_children(FlAccessibleNode* self,
                                      GPtrArray* children) {
   g_return_if_fail(FL_IS_ACCESSIBLE_NODE(self));

   g_ptr_array_remove_range(self->children, 0, self->children->len);
   for (guint i = 0; i < children->len; i++) {
     AtkObject* object = ATK_OBJECT(g_ptr_array_index(children, i));
     g_ptr_array_add(self->children, g_object_ref(object));
     g_signal_emit_by_name(self, "children-changed::add", i, object, nullptr);
   }
 }

 void fl_accessible_node_set_name(FlAccessibleNode* self, const gchar* name) {
   g_return_if_fail(FL_IS_ACCESSIBLE_NODE(self));
   g_free(self->name);
   self->name = g_strdup(name);
 }

 void fl_accessible_node_set_extents(FlAccessibleNode* self,
                                     gint x,
                                     gint y,
                                     gint width,
                                     gint height) {
   g_return_if_fail(FL_IS_ACCESSIBLE_NODE(self));
   self->x = x;
   self->y = y;
   self->width = width;
   self->height = height;
 }

 void fl_accessible_node_set_flags(FlAccessibleNode* self,
                                   FlutterSemanticsFlag flags) {
   g_return_if_fail(FL_IS_ACCESSIBLE_NODE(self));

   FlutterSemanticsFlag old_flags = self->flags;
   self->flags = flags;

   for (int i = 0; flag_mapping[i].state != ATK_STATE_INVALID; i++) {
     if (flag_is_changed(old_flags, flags, flag_mapping[i].flag)) {
       gboolean enabled = has_flag(flags, flag_mapping[i].flag);
       if (flag_mapping[i].invert) {
         enabled = !enabled;
       }

       atk_object_notify_state_change(ATK_OBJECT(self), flag_mapping[i].state,
                                      enabled);
     }
   }
 }

 void fl_accessible_node_set_actions(FlAccessibleNode* self,
                                     FlutterSemanticsAction actions) {
   g_return_if_fail(FL_IS_ACCESSIBLE_NODE(self));

   // NOTE(robert-ancell): It appears that AtkAction doesn't have a method of
   // notifying that actions have changed, and even if it did an ATK client
   // might access the old IDs before checking for new ones. Keep an eye
   // out for a case where Flutter changes the actions on an item and see
   // if we can resolve this in another way.
   g_ptr_array_remove_range(self->actions, 0, self->actions->len);
   for (int i = 0; action_mapping[i].name != nullptr; i++) {
     if (has_action(actions, action_mapping[i].action)) {
       g_ptr_array_add(self->actions, &action_mapping[i]);
     }
   }
 }
	// Copyright 2013 The Flutter Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#include "flutter/shell/platform/linux/fl_accessible_node.h"
	#include "flutter/shell/platform/linux/fl_engine_private.h"

	// Maps Flutter semantics flags to ATK flags.
	static struct {
	AtkStateType state;
	FlutterSemanticsFlag flag;
	gboolean invert;
	} flag_mapping[] = {
	{ATK_STATE_SHOWING, kFlutterSemanticsFlagIsObscured, TRUE},
	{ATK_STATE_VISIBLE, kFlutterSemanticsFlagIsHidden, TRUE},
	{ATK_STATE_CHECKABLE, kFlutterSemanticsFlagHasCheckedState, FALSE},
	{ATK_STATE_FOCUSABLE, kFlutterSemanticsFlagIsFocusable, FALSE},
	{ATK_STATE_FOCUSED, kFlutterSemanticsFlagIsFocused, FALSE},
	{ATK_STATE_CHECKED, kFlutterSemanticsFlagIsChecked, FALSE},
	{ATK_STATE_SELECTED, kFlutterSemanticsFlagIsSelected, FALSE},
	{ATK_STATE_ENABLED, kFlutterSemanticsFlagIsEnabled, FALSE},
	{ATK_STATE_READ_ONLY, kFlutterSemanticsFlagIsReadOnly, FALSE},
	{ATK_STATE_INVALID, static_cast<FlutterSemanticsFlag>(0), FALSE},
	};

	// Maps Flutter semantics actions to ATK actions.
	typedef struct {
	FlutterSemanticsAction action;
	const gchar* name;
	} ActionData;
	static ActionData action_mapping[] = {
	{kFlutterSemanticsActionTap, "Tap"},
	{kFlutterSemanticsActionLongPress, "LongPress"},
	{kFlutterSemanticsActionScrollLeft, "ScrollLeft"},
	{kFlutterSemanticsActionScrollRight, "ScrollRight"},
	{kFlutterSemanticsActionScrollUp, "ScrollUp"},
	{kFlutterSemanticsActionScrollDown, "ScrollDown"},
	{kFlutterSemanticsActionIncrease, "Increase"},
	{kFlutterSemanticsActionDecrease, "Decrease"},
	{kFlutterSemanticsActionShowOnScreen, "ShowOnScreen"},
	{kFlutterSemanticsActionMoveCursorForwardByCharacter,
	"MoveCursorForwardByCharacter"},
	{kFlutterSemanticsActionMoveCursorBackwardByCharacter,
	"MoveCursorBackwardByCharacter"},
	{kFlutterSemanticsActionSetSelection, "SetSelection"},
	{kFlutterSemanticsActionCopy, "Copy"},
	{kFlutterSemanticsActionCut, "Cut"},
	{kFlutterSemanticsActionPaste, "Paste"},
	{kFlutterSemanticsActionDidGainAccessibilityFocus,
	"DidGainAccessibilityFocus"},
	{kFlutterSemanticsActionDidLoseAccessibilityFocus,
	"DidLoseAccessibilityFocus"},
	{kFlutterSemanticsActionCustomAction, "CustomAction"},
	{kFlutterSemanticsActionDismiss, "Dismiss"},
	{kFlutterSemanticsActionMoveCursorForwardByWord, "MoveCursorForwardByWord"},
	{kFlutterSemanticsActionMoveCursorBackwardByWord,
	"MoveCursorBackwardByWord"},
	{static_cast<FlutterSemanticsAction>(0), nullptr}};

	struct _FlAccessibleNode {
	AtkObject parent_instance;

	// Weak reference to the engine this node is created for.
	FlEngine* engine;

	// Weak reference to the parent node of this one or %NULL.
	AtkObject* parent;

	int32_t id;
	gchar* name;
	gint x, y, width, height;
	GPtrArray* actions;
	gsize actions_length;
	GPtrArray* children;
	FlutterSemanticsFlag flags;
	};

	static void fl_accessible_node_component_interface_init(
	AtkComponentIface* iface);
	static void fl_accessible_node_action_interface_init(AtkActionIface* iface);
	static void fl_accessible_node_text_interface_init(AtkTextIface* iface);

	G_DEFINE_TYPE_WITH_CODE(
	FlAccessibleNode,
	fl_accessible_node,
	ATK_TYPE_OBJECT,
	G_IMPLEMENT_INTERFACE(ATK_TYPE_COMPONENT,
	fl_accessible_node_component_interface_init)
	G_IMPLEMENT_INTERFACE(ATK_TYPE_ACTION,
	fl_accessible_node_action_interface_init)
	G_IMPLEMENT_INTERFACE(ATK_TYPE_TEXT,
	fl_accessible_node_text_interface_init))

	// Returns TRUE if [flag] has changed between [old_flags] and [flags].
	static gboolean flag_is_changed(FlutterSemanticsFlag old_flags,
	FlutterSemanticsFlag flags,
	FlutterSemanticsFlag flag) {
	return (old_flags & flag) != (flags & flag);
	}

	// Returns TRUE if [flag] is set in [flags].
	static gboolean has_flag(FlutterSemanticsFlag flags,
	FlutterSemanticsFlag flag) {
	return (flags & flag) != 0;
	}

	// Returns TRUE if [action] is set in [actions].
	static gboolean has_action(FlutterSemanticsAction actions,
	FlutterSemanticsAction action) {
	return (actions & action) != 0;
	}

	// Gets the nth action.
	static ActionData* get_action(FlAccessibleNode* self, gint index) {
	if (index < 0 \|\| static_cast<guint>(index) >= self->actions->len)
	return nullptr;
	return static_cast<ActionData*>(g_ptr_array_index(self->actions, index));
	}

	static void fl_accessible_node_dispose(GObject* object) {
	FlAccessibleNode* self = FL_ACCESSIBLE_NODE(object);

	if (self->engine != nullptr) {
	g_object_remove_weak_pointer(G_OBJECT(self),
	reinterpret_cast<gpointer*>(&(self->engine)));
	self->engine = nullptr;
	}
	if (self->parent != nullptr) {
	g_object_remove_weak_pointer(G_OBJECT(self),
	reinterpret_cast<gpointer*>(&(self->parent)));
	self->parent = nullptr;
	}
	g_clear_pointer(&self->name, g_free);
	g_clear_pointer(&self->actions, g_ptr_array_unref);
	g_clear_pointer(&self->children, g_ptr_array_unref);

	G_OBJECT_CLASS(fl_accessible_node_parent_class)->dispose(object);
	}

	// Implements AtkObject::get_name.
	static const gchar* fl_accessible_node_get_name(AtkObject* accessible) {
	FlAccessibleNode* self = FL_ACCESSIBLE_NODE(accessible);
	return self->name;
	}

	// Implements AtkObject::get_parent.
	static AtkObject* fl_accessible_node_get_parent(AtkObject* accessible) {
	FlAccessibleNode* self = FL_ACCESSIBLE_NODE(accessible);
	return self->parent;
	}

	// Implements AtkObject::get_n_children.
	static gint fl_accessible_node_get_n_children(AtkObject* accessible) {
	FlAccessibleNode* self = FL_ACCESSIBLE_NODE(accessible);
	return self->children->len;
	}

	// Implements AtkObject::ref_child.
	static AtkObject* fl_accessible_node_ref_child(AtkObject* accessible, gint i) {
	FlAccessibleNode* self = FL_ACCESSIBLE_NODE(accessible);

	if (i < 0 \|\| static_cast<guint>(i) >= self->children->len) {
	return nullptr;
	}

	return ATK_OBJECT(g_object_ref(g_ptr_array_index(self->children, i)));
	}

	// Implements AtkObject::get_role.
	static AtkRole fl_accessible_node_get_role(AtkObject* accessible) {
	FlAccessibleNode* self = FL_ACCESSIBLE_NODE(accessible);
	if ((self->flags & kFlutterSemanticsFlagIsButton) != 0) {
	return ATK_ROLE_PUSH_BUTTON;
	}
	if ((self->flags & kFlutterSemanticsFlagIsTextField) != 0) {
	return ATK_ROLE_TEXT;
	}
	if ((self->flags & kFlutterSemanticsFlagIsHeader) != 0) {
	return ATK_ROLE_HEADER;
	}
	if ((self->flags & kFlutterSemanticsFlagIsLink) != 0) {
	return ATK_ROLE_LINK;
	}
	if ((self->flags & kFlutterSemanticsFlagIsImage) != 0) {
	return ATK_ROLE_IMAGE;
	}

	return ATK_ROLE_FRAME;
	}

	// Implements AtkObject::ref_state_set.
	static AtkStateSet* fl_accessible_node_ref_state_set(AtkObject* accessible) {
	FlAccessibleNode* self = FL_ACCESSIBLE_NODE(accessible);

	AtkStateSet* state_set = atk_state_set_new();

	for (int i = 0; flag_mapping[i].state != ATK_STATE_INVALID; i++) {
	gboolean enabled = has_flag(self->flags, flag_mapping[i].flag);
	if (flag_mapping[i].invert) {
	enabled = !enabled;
	}
	if (enabled) {
	atk_state_set_add_state(state_set, flag_mapping[i].state);
	}
	}

	return state_set;
	}

	// Implements AtkComponent::get_extents.
	static void fl_accessible_node_get_extents(AtkComponent* component,
	gint* x,
	gint* y,
	gint* width,
	gint* height,
	AtkCoordType coord_type) {
	FlAccessibleNode* self = FL_ACCESSIBLE_NODE(component);

	*x = 0;
	*y = 0;
	if (self->parent != nullptr) {
	atk_component_get_extents(ATK_COMPONENT(self->parent), x, y, nullptr,
	nullptr, coord_type);
	}

	*x += self->x;
	*y += self->y;
	*width = self->width;
	*height = self->height;
	}

	// Implements AtkComponent::get_layer.
	static AtkLayer fl_accessible_node_get_layer(AtkComponent* component) {
	return ATK_LAYER_WIDGET;
	}

	// Implements AtkAction::do_action.
	static gboolean fl_accessible_node_do_action(AtkAction* action, gint i) {
	FlAccessibleNode* self = FL_ACCESSIBLE_NODE(action);

	if (self->engine == nullptr) {
	return FALSE;
	}

	ActionData* data = get_action(self, i);
	if (data == nullptr) {
	return FALSE;
	}

	fl_engine_dispatch_semantics_action(self->engine, self->id, data->action,
	nullptr);
	return TRUE;
	}

	// Implements AtkAction::get_n_actions.
	static gint fl_accessible_node_get_n_actions(AtkAction* action) {
	FlAccessibleNode* self = FL_ACCESSIBLE_NODE(action);
	return self->actions->len;
	}

	// Implements AtkAction::get_name.
	static const gchar* fl_accessible_node_get_name(AtkAction* action, gint i) {
	FlAccessibleNode* self = FL_ACCESSIBLE_NODE(action);

	ActionData* data = get_action(self, i);
	if (data == nullptr) {
	return nullptr;
	}

	return data->name;
	}

	// Implements AtkText::get_text.
	static gchar* fl_accessible_node_get_text(AtkText* text,
	gint start_offset,
	gint end_offset) {
	return nullptr;
	}

	static void fl_accessible_node_class_init(FlAccessibleNodeClass* klass) {
	G_OBJECT_CLASS(klass)->dispose = fl_accessible_node_dispose;
	ATK_OBJECT_CLASS(klass)->get_name = fl_accessible_node_get_name;
	ATK_OBJECT_CLASS(klass)->get_parent = fl_accessible_node_get_parent;
	ATK_OBJECT_CLASS(klass)->get_n_children = fl_accessible_node_get_n_children;
	ATK_OBJECT_CLASS(klass)->ref_child = fl_accessible_node_ref_child;
	ATK_OBJECT_CLASS(klass)->get_role = fl_accessible_node_get_role;
	ATK_OBJECT_CLASS(klass)->ref_state_set = fl_accessible_node_ref_state_set;
	}

	static void fl_accessible_node_component_interface_init(
	AtkComponentIface* iface) {
	iface->get_extents = fl_accessible_node_get_extents;
	iface->get_layer = fl_accessible_node_get_layer;
	}

	static void fl_accessible_node_action_interface_init(AtkActionIface* iface) {
	iface->do_action = fl_accessible_node_do_action;
	iface->get_n_actions = fl_accessible_node_get_n_actions;
	iface->get_name = fl_accessible_node_get_name;
	}

	static void fl_accessible_node_text_interface_init(AtkTextIface* iface) {
	iface->get_text = fl_accessible_node_get_text;
	}

	static void fl_accessible_node_init(FlAccessibleNode* self) {
	self->actions = g_ptr_array_new();
	self->children = g_ptr_array_new_with_free_func(g_object_unref);
	}

	FlAccessibleNode* fl_accessible_node_new(FlEngine* engine, int32_t id) {
	FlAccessibleNode* self =
	FL_ACCESSIBLE_NODE(g_object_new(fl_accessible_node_get_type(), nullptr));
	self->engine = engine;
	g_object_add_weak_pointer(G_OBJECT(self),
	reinterpret_cast<gpointer*>(&(self->engine)));
	self->id = id;
	return self;
	}

	void fl_accessible_node_set_parent(FlAccessibleNode* self, AtkObject* parent) {
	g_return_if_fail(FL_IS_ACCESSIBLE_NODE(self));
	self->parent = parent;
	g_object_add_weak_pointer(G_OBJECT(self),
	reinterpret_cast<gpointer*>(&(self->parent)));
	}

	void fl_accessible_node_set_children(FlAccessibleNode* self,
	GPtrArray* children) {
	g_return_if_fail(FL_IS_ACCESSIBLE_NODE(self));

	g_ptr_array_remove_range(self->children, 0, self->children->len);
	for (guint i = 0; i < children->len; i++) {
	AtkObject* object = ATK_OBJECT(g_ptr_array_index(children, i));
	g_ptr_array_add(self->children, g_object_ref(object));
	g_signal_emit_by_name(self, "children-changed::add", i, object, nullptr);
	}
	}

	void fl_accessible_node_set_name(FlAccessibleNode* self, const gchar* name) {
	g_return_if_fail(FL_IS_ACCESSIBLE_NODE(self));
	g_free(self->name);
	self->name = g_strdup(name);
	}

	void fl_accessible_node_set_extents(FlAccessibleNode* self,
	gint x,
	gint y,
	gint width,
	gint height) {
	g_return_if_fail(FL_IS_ACCESSIBLE_NODE(self));
	self->x = x;
	self->y = y;
	self->width = width;
	self->height = height;
	}

	void fl_accessible_node_set_flags(FlAccessibleNode* self,
	FlutterSemanticsFlag flags) {
	g_return_if_fail(FL_IS_ACCESSIBLE_NODE(self));

	FlutterSemanticsFlag old_flags = self->flags;
	self->flags = flags;

	for (int i = 0; flag_mapping[i].state != ATK_STATE_INVALID; i++) {
	if (flag_is_changed(old_flags, flags, flag_mapping[i].flag)) {
	gboolean enabled = has_flag(flags, flag_mapping[i].flag);
	if (flag_mapping[i].invert) {
	enabled = !enabled;
	}

	atk_object_notify_state_change(ATK_OBJECT(self), flag_mapping[i].state,
	enabled);
	}
	}
	}

	void fl_accessible_node_set_actions(FlAccessibleNode* self,
	FlutterSemanticsAction actions) {
	g_return_if_fail(FL_IS_ACCESSIBLE_NODE(self));

	// NOTE(robert-ancell): It appears that AtkAction doesn't have a method of
	// notifying that actions have changed, and even if it did an ATK client
	// might access the old IDs before checking for new ones. Keep an eye
	// out for a case where Flutter changes the actions on an item and see
	// if we can resolve this in another way.
	g_ptr_array_remove_range(self->actions, 0, self->actions->len);
	for (int i = 0; action_mapping[i].name != nullptr; i++) {
	if (has_action(actions, action_mapping[i].action)) {
	g_ptr_array_add(self->actions, &action_mapping[i]);
	}
	}
	}