gecko-dev/accessible/src/atk/ApplicationAccessibleWrap.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 et sw=2 tw=80: */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 * Sun Microsystems, Inc.
 * Portions created by the Initial Developer are Copyright (C) 2002
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Bolian Yin (bolian.yin@sun.com)
 *   Ginn Chen (ginn.chen@sun.com)
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "ApplicationAccessibleWrap.h"

#include "nsCOMPtr.h"
#include "nsMai.h"
#include "prlink.h"
#include "prenv.h"
#include "nsIGConfService.h"
#include "nsIServiceManager.h"
#include "nsAutoPtr.h"
#include "nsAccessibilityService.h"
#include "AtkSocketAccessible.h"

#include <gtk/gtk.h>
#include <atk/atk.h>
#ifdef MOZ_ENABLE_DBUS
#include <dbus/dbus.h>
#endif

using namespace mozilla;
using namespace mozilla::a11y;

typedef GType (* AtkGetTypeType) (void);
GType g_atk_hyperlink_impl_type = G_TYPE_INVALID;
static bool sATKChecked = false;
static PRLibrary *sATKLib = nsnull;
static const char sATKLibName[] = "libatk-1.0.so.0";
static const char sATKHyperlinkImplGetTypeSymbol[] =
  "atk_hyperlink_impl_get_type";

/* gail function pointer */
static guint (* gail_add_global_event_listener) (GSignalEmissionHook listener,
                                                 const gchar *event_type);
static void (* gail_remove_global_event_listener) (guint remove_listener);
static void (* gail_remove_key_event_listener) (guint remove_listener);
static AtkObject * (*gail_get_root) (void);

/* maiutil */

static guint mai_util_add_global_event_listener(GSignalEmissionHook listener,
                                                const gchar *event_type);
static void mai_util_remove_global_event_listener(guint remove_listener);
static guint mai_util_add_key_event_listener(AtkKeySnoopFunc listener,
                                             gpointer data);
static void mai_util_remove_key_event_listener(guint remove_listener);
static AtkObject *mai_util_get_root(void);
static G_CONST_RETURN gchar *mai_util_get_toolkit_name(void);
static G_CONST_RETURN gchar *mai_util_get_toolkit_version(void);


/* Misc */

static void _listener_info_destroy(gpointer data);
static guint add_listener (GSignalEmissionHook listener,
                           const gchar *object_type,
                           const gchar *signal,
                           const gchar *hook_data,
                           guint gail_listenerid = 0);
static AtkKeyEventStruct *atk_key_event_from_gdk_event_key(GdkEventKey *key);
static gboolean notify_hf(gpointer key, gpointer value, gpointer data);
static void insert_hf(gpointer key, gpointer value, gpointer data);
static gint mai_key_snooper(GtkWidget *the_widget, GdkEventKey *event,
                            gpointer func_data);

static GHashTable* sListener_list = NULL;
static gint sListener_idx = 1;

#define MAI_TYPE_UTIL              (mai_util_get_type ())
#define MAI_UTIL(obj)              (G_TYPE_CHECK_INSTANCE_CAST ((obj), \
                                    MAI_TYPE_UTIL, MaiUtil))
#define MAI_UTIL_CLASS(klass)      (G_TYPE_CHECK_CLASS_CAST ((klass), \
                                    MAI_TYPE_UTIL, MaiUtilClass))
#define MAI_IS_UTIL(obj)           (G_TYPE_CHECK_INSTANCE_TYPE ((obj), \
                                    MAI_TYPE_UTIL))
#define MAI_IS_UTIL_CLASS(klass)   (G_TYPE_CHECK_CLASS_TYPE ((klass), \
                                    MAI_TYPE_UTIL))
#define MAI_UTIL_GET_CLASS(obj)    (G_TYPE_INSTANCE_GET_CLASS ((obj), \
                                    MAI_TYPE_UTIL, MaiUtilClass))

static GHashTable* sKey_listener_list = NULL;
static guint sKey_snooper_id = 0;
static bool sToplevel_event_hook_added = false;
static gulong sToplevel_show_hook = 0;
static gulong sToplevel_hide_hook = 0;

G_BEGIN_DECLS
typedef void (*GnomeAccessibilityInit) (void);
typedef void (*GnomeAccessibilityShutdown) (void);
G_END_DECLS

struct MaiUtil
{
    AtkUtil parent;
    GList *listener_list;
};

struct MaiKeyEventInfo
{
    AtkKeyEventStruct *key_event;
    gpointer func_data;
};

union AtkKeySnoopFuncPointer
{
    AtkKeySnoopFunc func_ptr;
    gpointer data;
};

struct GnomeAccessibilityModule
{
    const char *libName;
    PRLibrary *lib;
    const char *initName;
    GnomeAccessibilityInit init;
    const char *shutdownName;
    GnomeAccessibilityShutdown shutdown;
};

struct MaiUtilClass
{
    AtkUtilClass parent_class;
};

GType mai_util_get_type (void);
static void mai_util_class_init(MaiUtilClass *klass);

/* supporting */
PRLogModuleInfo *gMaiLog = NULL;

#define MAI_VERSION MOZILLA_VERSION
#define MAI_NAME "Gecko"

struct MaiUtilListenerInfo
{
    gint key;
    guint signal_id;
    gulong hook_id;
    // For window create/destory/minimize/maximize/restore/activate/deactivate
    // events, we'll chain gail_util's add/remove_global_event_listener.
    // So we store the listenerid returned by gail's add_global_event_listener
    // in this structure to call gail's remove_global_event_listener later.
    guint gail_listenerid;
};

static GnomeAccessibilityModule sAtkBridge = {
#ifdef AIX
    "libatk-bridge.a(libatk-bridge.so.0)", NULL,
#else
    "libatk-bridge.so", NULL,
#endif
    "gnome_accessibility_module_init", NULL,
    "gnome_accessibility_module_shutdown", NULL
};

static GnomeAccessibilityModule sGail = {
    "libgail.so", NULL,
    "gnome_accessibility_module_init", NULL,
    "gnome_accessibility_module_shutdown", NULL
};

GType
mai_util_get_type(void)
{
    static GType type = 0;

    if (!type) {
        static const GTypeInfo tinfo = {
            sizeof(MaiUtilClass),
            (GBaseInitFunc) NULL, /* base init */
            (GBaseFinalizeFunc) NULL, /* base finalize */
            (GClassInitFunc) mai_util_class_init, /* class init */
            (GClassFinalizeFunc) NULL, /* class finalize */
            NULL, /* class data */
            sizeof(MaiUtil), /* instance size */
            0, /* nb preallocs */
            (GInstanceInitFunc) NULL, /* instance init */
            NULL /* value table */
        };

        type = g_type_register_static(ATK_TYPE_UTIL,
                                      "MaiUtil", &tinfo, GTypeFlags(0));
    }
    return type;
}

static void
window_added (AtkObject *atk_obj,
              guint     index,
              AtkObject *child)
{
  if (!IS_MAI_OBJECT(child))
      return;

  static guint id =  g_signal_lookup ("create", MAI_TYPE_ATK_OBJECT);
  g_signal_emit (child, id, 0);
}

static void
window_removed (AtkObject *atk_obj,
                guint     index,
                AtkObject *child)
{
  if (!IS_MAI_OBJECT(child))
      return;

  static guint id =  g_signal_lookup ("destroy", MAI_TYPE_ATK_OBJECT);
  g_signal_emit (child, id, 0);
}

/* intialize the the atk interface (function pointers) with MAI implementation.
 * When atk bridge get loaded, these interface can be used.
 */
static void
mai_util_class_init(MaiUtilClass *klass)
{
    AtkUtilClass *atk_class;
    gpointer data;

    data = g_type_class_peek(ATK_TYPE_UTIL);
    atk_class = ATK_UTIL_CLASS(data);

    // save gail function pointer
    gail_add_global_event_listener = atk_class->add_global_event_listener;
    gail_remove_global_event_listener = atk_class->remove_global_event_listener;
    gail_remove_key_event_listener = atk_class->remove_key_event_listener;
    gail_get_root = atk_class->get_root;

    atk_class->add_global_event_listener =
        mai_util_add_global_event_listener;
    atk_class->remove_global_event_listener =
        mai_util_remove_global_event_listener;
    atk_class->add_key_event_listener = mai_util_add_key_event_listener;
    atk_class->remove_key_event_listener = mai_util_remove_key_event_listener;
    atk_class->get_root = mai_util_get_root;
    atk_class->get_toolkit_name = mai_util_get_toolkit_name;
    atk_class->get_toolkit_version = mai_util_get_toolkit_version;

    sListener_list = g_hash_table_new_full(g_int_hash, g_int_equal, NULL,
                                           _listener_info_destroy);
    // Keep track of added/removed windows.
    AtkObject *root = atk_get_root ();
    g_signal_connect (root, "children-changed::add", (GCallback) window_added, NULL);
    g_signal_connect (root, "children-changed::remove", (GCallback) window_removed, NULL);
}

static guint
mai_util_add_global_event_listener(GSignalEmissionHook listener,
                                   const gchar *event_type)
{
    guint rc = 0;
    gchar **split_string;

    split_string = g_strsplit (event_type, ":", 3);

    if (split_string) {
        if (!strcmp ("window", split_string[0])) {
            guint gail_listenerid = 0;
            if (gail_add_global_event_listener) {
                // call gail's function to track gtk native window events
                gail_listenerid =
                    gail_add_global_event_listener(listener, event_type);
            }

            rc = add_listener (listener, "MaiAtkObject", split_string[1],
                               event_type, gail_listenerid);
        }
        else {
            rc = add_listener (listener, split_string[1], split_string[2],
                               event_type);
        }
        g_strfreev(split_string);
    }
    return rc;
}

static void
mai_util_remove_global_event_listener(guint remove_listener)
{
    if (remove_listener > 0) {
        MaiUtilListenerInfo *listener_info;
        gint tmp_idx = remove_listener;

        listener_info = (MaiUtilListenerInfo *)
            g_hash_table_lookup(sListener_list, &tmp_idx);

        if (listener_info != NULL) {
            if (gail_remove_global_event_listener &&
                listener_info->gail_listenerid) {
              gail_remove_global_event_listener(listener_info->gail_listenerid);
            }

            /* Hook id of 0 and signal id of 0 are invalid */
            if (listener_info->hook_id != 0 && listener_info->signal_id != 0) {
                /* Remove the emission hook */
                g_signal_remove_emission_hook(listener_info->signal_id,
                                              listener_info->hook_id);

                /* Remove the element from the hash */
                g_hash_table_remove(sListener_list, &tmp_idx);
            }
            else {
                g_warning("Invalid listener hook_id %ld or signal_id %d\n",
                          listener_info->hook_id, listener_info->signal_id);
            }
        }
        else {
            // atk-bridge is initialized with gail (e.g. yelp)
            // try gail_remove_global_event_listener
            if (gail_remove_global_event_listener) {
                return gail_remove_global_event_listener(remove_listener);
            }

            g_warning("No listener with the specified listener id %d",
                      remove_listener);
        }
    }
    else {
        g_warning("Invalid listener_id %d", remove_listener);
    }
}

static AtkKeyEventStruct *
atk_key_event_from_gdk_event_key (GdkEventKey *key)
{
    AtkKeyEventStruct *event = g_new0(AtkKeyEventStruct, 1);
    switch (key->type) {
    case GDK_KEY_PRESS:
        event->type = ATK_KEY_EVENT_PRESS;
        break;
    case GDK_KEY_RELEASE:
        event->type = ATK_KEY_EVENT_RELEASE;
        break;
    default:
        g_assert_not_reached ();
        return NULL;
    }
    event->state = key->state;
    event->keyval = key->keyval;
    event->length = key->length;
    if (key->string && key->string [0] &&
        (key->state & GDK_CONTROL_MASK ||
         g_unichar_isgraph (g_utf8_get_char (key->string)))) {
        event->string = key->string;
    }
    else if (key->type == GDK_KEY_PRESS ||
             key->type == GDK_KEY_RELEASE) {
        event->string = gdk_keyval_name (key->keyval);
    }
    event->keycode = key->hardware_keycode;
    event->timestamp = key->time;

    MAI_LOG_DEBUG(("MaiKey:\tsym %u\n\tmods %x\n\tcode %u\n\ttime %lx\n",
                   (unsigned int) event->keyval,
                   (unsigned int) event->state,
                   (unsigned int) event->keycode,
                   (unsigned long int) event->timestamp));
    return event;
}

static gboolean
notify_hf(gpointer key, gpointer value, gpointer data)
{
    MaiKeyEventInfo *info = (MaiKeyEventInfo *)data;
    AtkKeySnoopFuncPointer atkKeySnoop;
    atkKeySnoop.data = value;
    return (atkKeySnoop.func_ptr)(info->key_event, info->func_data) ? TRUE : FALSE;
}

static void
insert_hf(gpointer key, gpointer value, gpointer data)
{
    GHashTable *new_table = (GHashTable *) data;
    g_hash_table_insert (new_table, key, value);
}

static gint
mai_key_snooper(GtkWidget *the_widget, GdkEventKey *event, gpointer func_data)
{
    /* notify each AtkKeySnoopFunc in turn... */

    MaiKeyEventInfo *info = g_new0(MaiKeyEventInfo, 1);
    gint consumed = 0;
    if (sKey_listener_list) {
        GHashTable *new_hash = g_hash_table_new(NULL, NULL);
        g_hash_table_foreach (sKey_listener_list, insert_hf, new_hash);
        info->key_event = atk_key_event_from_gdk_event_key (event);
        info->func_data = func_data;
        consumed = g_hash_table_foreach_steal (new_hash, notify_hf, info);
        g_hash_table_destroy (new_hash);
        g_free(info->key_event);
    }
    g_free(info);
    return (consumed ? 1 : 0);
}

static guint
mai_util_add_key_event_listener (AtkKeySnoopFunc listener,
                                 gpointer data)
{
    NS_ENSURE_TRUE(listener, 0);

    static guint key=0;

    if (!sKey_listener_list) {
        sKey_listener_list = g_hash_table_new(NULL, NULL);
        sKey_snooper_id = gtk_key_snooper_install(mai_key_snooper, data);
    }
    AtkKeySnoopFuncPointer atkKeySnoop;
    atkKeySnoop.func_ptr = listener;
    g_hash_table_insert(sKey_listener_list, GUINT_TO_POINTER (key++),
                        atkKeySnoop.data);
    return key;
}

static void
mai_util_remove_key_event_listener (guint remove_listener)
{
    if (!sKey_listener_list) {
        // atk-bridge is initialized with gail (e.g. yelp)
        // try gail_remove_key_event_listener
        return gail_remove_key_event_listener(remove_listener);
    }

    g_hash_table_remove(sKey_listener_list, GUINT_TO_POINTER (remove_listener));
    if (g_hash_table_size(sKey_listener_list) == 0) {
        gtk_key_snooper_remove(sKey_snooper_id);
    }
}

AtkObject*
mai_util_get_root(void)
{
  if (nsAccessibilityService::IsShutdown()) {
    // We've shutdown, try to use gail instead
    // (to avoid assert in spi_atk_tidy_windows())
    if (gail_get_root)
      return gail_get_root();

    return nsnull;
  }

  return nsAccessNode::GetApplicationAccessible()->GetAtkObject();
}

G_CONST_RETURN gchar *
mai_util_get_toolkit_name(void)
{
    return MAI_NAME;
}

G_CONST_RETURN gchar *
mai_util_get_toolkit_version(void)
{
    return MAI_VERSION;
}

void
_listener_info_destroy(gpointer data)
{
    g_free(data);
}

guint
add_listener (GSignalEmissionHook listener,
              const gchar *object_type,
              const gchar *signal,
              const gchar *hook_data,
              guint gail_listenerid)
{
    GType type;
    guint signal_id;
    gint rc = 0;

    type = g_type_from_name(object_type);
    if (type) {
        signal_id = g_signal_lookup(signal, type);
        if (signal_id > 0) {
            MaiUtilListenerInfo *listener_info;

            rc = sListener_idx;

            listener_info =  (MaiUtilListenerInfo *)
                g_malloc(sizeof(MaiUtilListenerInfo));
            listener_info->key = sListener_idx;
            listener_info->hook_id =
                g_signal_add_emission_hook(signal_id, 0, listener,
                                           g_strdup(hook_data),
                                           (GDestroyNotify)g_free);
            listener_info->signal_id = signal_id;
            listener_info->gail_listenerid = gail_listenerid;

            g_hash_table_insert(sListener_list, &(listener_info->key),
                                listener_info);
            sListener_idx++;
        }
        else {
            g_warning("Invalid signal type %s\n", signal);
        }
    }
    else {
        g_warning("Invalid object type %s\n", object_type);
    }
    return rc;
}

static nsresult LoadGtkModule(GnomeAccessibilityModule& aModule);

// ApplicationAccessibleWrap

ApplicationAccessibleWrap::ApplicationAccessibleWrap():
  ApplicationAccessible()
{
  MAI_LOG_DEBUG(("======Create AppRootAcc=%p\n", (void*)this));
}

ApplicationAccessibleWrap::~ApplicationAccessibleWrap()
{
    MAI_LOG_DEBUG(("======Destory AppRootAcc=%p\n", (void*)this));
    nsAccessibleWrap::ShutdownAtkObject();
}

static gboolean
toplevel_event_watcher(GSignalInvocationHint* ihint,
                       guint                  n_param_values,
                       const GValue*          param_values,
                       gpointer               data)
{
  static GQuark sQuark_gecko_acc_obj = 0;

  if (!sQuark_gecko_acc_obj)
    sQuark_gecko_acc_obj = g_quark_from_static_string("GeckoAccObj");

  if (nsAccessibilityService::IsShutdown())
    return TRUE;

  GObject* object = reinterpret_cast<GObject*>(g_value_get_object(param_values));
  if (!GTK_IS_WINDOW(object))
    return TRUE;

  AtkObject* child = gtk_widget_get_accessible(GTK_WIDGET(object));

  // GTK native dialog
  if (!IS_MAI_OBJECT(child) &&
      (atk_object_get_role(child) == ATK_ROLE_DIALOG)) {

    if (data == reinterpret_cast<gpointer>(nsIAccessibleEvent::EVENT_SHOW)) {

      // Attach the dialog accessible to app accessible tree
      nsAccessible* windowAcc = GetAccService()->AddNativeRootAccessible(child);
      g_object_set_qdata(G_OBJECT(child), sQuark_gecko_acc_obj,
                         reinterpret_cast<gpointer>(windowAcc));

    } else {

      // Deattach the dialog accessible
      nsAccessible* windowAcc =
        reinterpret_cast<nsAccessible*>
                        (g_object_get_qdata(G_OBJECT(child), sQuark_gecko_acc_obj));
      if (windowAcc) {
        GetAccService()->RemoveNativeRootAccessible(windowAcc);
        g_object_set_qdata(G_OBJECT(child), sQuark_gecko_acc_obj, NULL);
      }

    }
  }

  return TRUE;
}

bool
ApplicationAccessibleWrap::Init()
{
    if (ShouldA11yBeEnabled()) {
        // load and initialize gail library
        nsresult rv = LoadGtkModule(sGail);
        if (NS_SUCCEEDED(rv)) {
            (*sGail.init)();
        }
        else {
            MAI_LOG_DEBUG(("Fail to load lib: %s\n", sGail.libName));
        }

        MAI_LOG_DEBUG(("Mozilla Atk Implementation initializing\n"));
        // Initialize the MAI Utility class
        // it will overwrite gail_util
        g_type_class_unref(g_type_class_ref(MAI_TYPE_UTIL));

        // Init atk-bridge now
        PR_SetEnv("NO_AT_BRIDGE=0");

        // load and initialize atk-bridge library
        rv = LoadGtkModule(sAtkBridge);
        if (NS_SUCCEEDED(rv)) {
            // init atk-bridge
            (*sAtkBridge.init)();
        }
        else
            MAI_LOG_DEBUG(("Fail to load lib: %s\n", sAtkBridge.libName));

        if (!sToplevel_event_hook_added) {
          sToplevel_event_hook_added = true;
          sToplevel_show_hook =
            g_signal_add_emission_hook(g_signal_lookup("show", GTK_TYPE_WINDOW),
              0, toplevel_event_watcher,
              reinterpret_cast<gpointer>(nsIAccessibleEvent::EVENT_SHOW), NULL);
          sToplevel_hide_hook =
            g_signal_add_emission_hook(g_signal_lookup("hide", GTK_TYPE_WINDOW),
              0, toplevel_event_watcher,
              reinterpret_cast<gpointer>(nsIAccessibleEvent::EVENT_HIDE), NULL);
        }
    }

    return ApplicationAccessible::Init();
}

void
ApplicationAccessibleWrap::Unload()
{
    if (sToplevel_event_hook_added) {
      sToplevel_event_hook_added = false;
      g_signal_remove_emission_hook(g_signal_lookup("show", GTK_TYPE_WINDOW),
                                    sToplevel_show_hook);
      g_signal_remove_emission_hook(g_signal_lookup("hide", GTK_TYPE_WINDOW),
                                    sToplevel_hide_hook);
    }

    if (sAtkBridge.lib) {
        // Do not shutdown/unload atk-bridge,
        // an exit function registered will take care of it
        // if (sAtkBridge.shutdown)
        //     (*sAtkBridge.shutdown)();
        // PR_UnloadLibrary(sAtkBridge.lib);
        sAtkBridge.lib = NULL;
        sAtkBridge.init = NULL;
        sAtkBridge.shutdown = NULL;
    }
    if (sGail.lib) {
        // Do not shutdown gail because
        // 1) Maybe it's not init-ed by us. e.g. GtkEmbed
        // 2) We need it to avoid assert in spi_atk_tidy_windows
        // if (sGail.shutdown)
        //   (*sGail.shutdown)();
        // PR_UnloadLibrary(sGail.lib);
        sGail.lib = NULL;
        sGail.init = NULL;
        sGail.shutdown = NULL;
    }
    // if (sATKLib) {
    //     PR_UnloadLibrary(sATKLib);
    //     sATKLib = nsnull;
    // }
}

ENameValueFlag
ApplicationAccessibleWrap::Name(nsString& aName)
{
  // ATK doesn't provide a way to obtain an application name (for example,
  // Firefox or Thunderbird) like IA2 does. Thus let's return an application
  // name as accessible name that was used to get a branding name (for example,
  // Minefield aka nightly Firefox or Daily aka nightly Thunderbird).
  GetAppName(aName);
  return eNameOK;
}

NS_IMETHODIMP
ApplicationAccessibleWrap::GetNativeInterface(void** aOutAccessible)
{
    *aOutAccessible = nsnull;

    if (!mAtkObject) {
        mAtkObject =
            reinterpret_cast<AtkObject *>
                            (g_object_new(MAI_TYPE_ATK_OBJECT, NULL));
        NS_ENSURE_TRUE(mAtkObject, NS_ERROR_OUT_OF_MEMORY);

        atk_object_initialize(mAtkObject, this);
        mAtkObject->role = ATK_ROLE_INVALID;
        mAtkObject->layer = ATK_LAYER_INVALID;
    }

    *aOutAccessible = mAtkObject;
    return NS_OK;
}

struct AtkRootAccessibleAddedEvent {
  AtkObject *app_accessible;
  AtkObject *root_accessible;
  PRUint32 index;
};

gboolean fireRootAccessibleAddedCB(gpointer data)
{
    AtkRootAccessibleAddedEvent* eventData = (AtkRootAccessibleAddedEvent*)data;
    g_signal_emit_by_name(eventData->app_accessible, "children_changed::add",
                          eventData->index, eventData->root_accessible, NULL);
    g_object_unref(eventData->app_accessible);
    g_object_unref(eventData->root_accessible);
    free(data);

    return FALSE;
}

bool
ApplicationAccessibleWrap::AppendChild(nsAccessible* aChild)
{
    if (!ApplicationAccessible::AppendChild(aChild))
      return false;

    AtkObject *atkAccessible = nsAccessibleWrap::GetAtkObject(aChild);
    atk_object_set_parent(atkAccessible, mAtkObject);

    PRUint32 count = mChildren.Length();

    // Emit children_changed::add in a timeout
    // to make sure aRootAccWrap is fully initialized.
    AtkRootAccessibleAddedEvent* eventData = (AtkRootAccessibleAddedEvent*)
      malloc(sizeof(AtkRootAccessibleAddedEvent));
    if (eventData) {
      eventData->app_accessible = mAtkObject;
      eventData->root_accessible = atkAccessible;
      eventData->index = count -1;
      g_object_ref(mAtkObject);
      g_object_ref(atkAccessible);
      g_timeout_add(0, fireRootAccessibleAddedCB, eventData);
    }

    return true;
}

bool
ApplicationAccessibleWrap::RemoveChild(nsAccessible* aChild)
{
    PRInt32 index = aChild->IndexInParent();

    AtkObject *atkAccessible = nsAccessibleWrap::GetAtkObject(aChild);
    atk_object_set_parent(atkAccessible, NULL);
    g_signal_emit_by_name(mAtkObject, "children_changed::remove", index,
                          atkAccessible, NULL);

    return ApplicationAccessible::RemoveChild(aChild);
}

void
ApplicationAccessibleWrap::PreCreate()
{
    if (!sATKChecked) {
        sATKLib = PR_LoadLibrary(sATKLibName);
        if (sATKLib) {
            AtkGetTypeType pfn_atk_hyperlink_impl_get_type = (AtkGetTypeType) PR_FindFunctionSymbol(sATKLib, sATKHyperlinkImplGetTypeSymbol);
            if (pfn_atk_hyperlink_impl_get_type)
                g_atk_hyperlink_impl_type = pfn_atk_hyperlink_impl_get_type();

            AtkGetTypeType pfn_atk_socket_get_type;
            pfn_atk_socket_get_type = (AtkGetTypeType)
                                      PR_FindFunctionSymbol(sATKLib,
                                                            AtkSocketAccessible::sATKSocketGetTypeSymbol);
            if (pfn_atk_socket_get_type) {
                AtkSocketAccessible::g_atk_socket_type =
                  pfn_atk_socket_get_type();
                AtkSocketAccessible::g_atk_socket_embed = (AtkSocketEmbedType)
                  PR_FindFunctionSymbol(sATKLib,
                                        AtkSocketAccessible
                                          ::sATKSocketEmbedSymbol);
            AtkSocketAccessible::gCanEmbed =
              AtkSocketAccessible::g_atk_socket_type != G_TYPE_INVALID &&
              AtkSocketAccessible::g_atk_socket_embed;
            }
        }
        sATKChecked = true;
    }
}

static nsresult
LoadGtkModule(GnomeAccessibilityModule& aModule)
{
    NS_ENSURE_ARG(aModule.libName);

    if (!(aModule.lib = PR_LoadLibrary(aModule.libName))) {

        MAI_LOG_DEBUG(("Fail to load lib: %s in default path\n", aModule.libName));

        //try to load the module with "gtk-2.0/modules" appended
        char *curLibPath = PR_GetLibraryPath();
        nsCAutoString libPath(curLibPath);
#if defined(LINUX) && defined(__x86_64__)
        libPath.Append(":/usr/lib64:/usr/lib");
#else
        libPath.Append(":/usr/lib");
#endif
        MAI_LOG_DEBUG(("Current Lib path=%s\n", libPath.get()));
        PR_FreeLibraryName(curLibPath);

        PRInt16 loc1 = 0, loc2 = 0;
        PRInt16 subLen = 0;
        while (loc2 >= 0) {
            loc2 = libPath.FindChar(':', loc1);
            if (loc2 < 0)
                subLen = libPath.Length() - loc1;
            else
                subLen = loc2 - loc1;
            nsCAutoString sub(Substring(libPath, loc1, subLen));
            sub.Append("/gtk-2.0/modules/");
            sub.Append(aModule.libName);
            aModule.lib = PR_LoadLibrary(sub.get());
            if (aModule.lib) {
                MAI_LOG_DEBUG(("Ok, load %s from %s\n", aModule.libName, sub.get()));
                break;
            }
            loc1 = loc2+1;
        }
        if (!aModule.lib) {
            MAI_LOG_DEBUG(("Fail to load %s\n", aModule.libName));
            return NS_ERROR_FAILURE;
        }
    }

    //we have loaded the library, try to get the function ptrs
    if (!(aModule.init = PR_FindFunctionSymbol(aModule.lib,
                                               aModule.initName)) ||
        !(aModule.shutdown = PR_FindFunctionSymbol(aModule.lib,
                                                   aModule.shutdownName))) {

        //fail, :(
        MAI_LOG_DEBUG(("Fail to find symbol %s in %s",
                       aModule.init ? aModule.shutdownName : aModule.initName,
                       aModule.libName));
        PR_UnloadLibrary(aModule.lib);
        aModule.lib = NULL;
        return NS_ERROR_FAILURE;
    }
    return NS_OK;
}

namespace mozilla {
namespace a11y {

  static const char sAccEnv [] = "GNOME_ACCESSIBILITY";
#ifdef MOZ_ENABLE_DBUS
static DBusPendingCall *sPendingCall = nsnull;
#endif

void
PreInit()
{
#ifdef MOZ_ENABLE_DBUS
  static bool sChecked = FALSE;
  if (sChecked)
    return;

  sChecked = TRUE;

  // dbus is only checked if GNOME_ACCESSIBILITY is unset
  // also make sure that a session bus address is available to prevent dbus from
  // starting a new one.  Dbus confuses the test harness when it creates a new
  // process (see bug 693343)
  if (PR_GetEnv(sAccEnv) || !PR_GetEnv("DBUS_SESSION_BUS_ADDRESS"))
    return;

  DBusConnection* bus = dbus_bus_get(DBUS_BUS_SESSION, nsnull);
  if (!bus)
    return;

  dbus_connection_set_exit_on_disconnect(bus, FALSE);

  static const char* iface = "org.a11y.Status";
  static const char* member = "IsEnabled";
  DBusMessage *message;
  message = dbus_message_new_method_call("org.a11y.Bus", "/org/a11y/bus",
                                         "org.freedesktop.DBus.Properties",
                                         "Get");
  if (!message)
    goto dbus_done;

  dbus_message_append_args(message, DBUS_TYPE_STRING, &iface,
                           DBUS_TYPE_STRING, &member, DBUS_TYPE_INVALID);
  dbus_connection_send_with_reply(bus, message, &sPendingCall, 1000);
  dbus_message_unref(message);

dbus_done:
  dbus_connection_unref(bus);
#endif
}

bool
ShouldA11yBeEnabled()
{
  static bool sChecked = false, sShouldEnable = false;
  if (sChecked)
    return sShouldEnable;

  sChecked = true;

  // check if accessibility enabled/disabled by environment variable
  const char* envValue = PR_GetEnv(sAccEnv);
  if (envValue)
    return sShouldEnable = !!atoi(envValue);

#ifdef MOZ_ENABLE_DBUS
  PreInit();
  bool dbusSuccess = false;
  DBusMessage *reply = nsnull;
  if (!sPendingCall)
    goto dbus_done;

  dbus_pending_call_block(sPendingCall);
  reply = dbus_pending_call_steal_reply(sPendingCall);
  dbus_pending_call_unref(sPendingCall);
  sPendingCall = nsnull;
  if (!reply ||
      dbus_message_get_type(reply) != DBUS_MESSAGE_TYPE_METHOD_RETURN ||
      strcmp(dbus_message_get_signature (reply), DBUS_TYPE_VARIANT_AS_STRING))
    goto dbus_done;

  DBusMessageIter iter, iter_variant, iter_struct;
  dbus_bool_t dResult;
  dbus_message_iter_init(reply, &iter);
  dbus_message_iter_recurse (&iter, &iter_variant);
  switch (dbus_message_iter_get_arg_type(&iter_variant)) {
    case DBUS_TYPE_STRUCT:
      // at-spi2-core 2.2.0-2.2.1 had a bug where it returned a struct
      dbus_message_iter_recurse(&iter_variant, &iter_struct);
      if (dbus_message_iter_get_arg_type(&iter_struct) == DBUS_TYPE_BOOLEAN) {
        dbus_message_iter_get_basic(&iter_struct, &dResult);
        sShouldEnable = dResult;
        dbusSuccess = true;
      }

      break;
    case DBUS_TYPE_BOOLEAN:
      dbus_message_iter_get_basic(&iter_variant, &dResult);
      sShouldEnable = dResult;
      dbusSuccess = true;
      break;
    default:
      break;
  }

dbus_done:
  if (reply)
    dbus_message_unref(reply);

  if (dbusSuccess)
    return sShouldEnable;
#endif

  //check gconf-2 setting
static const char sGconfAccessibilityKey[] =
    "/desktop/gnome/interface/accessibility";
  nsresult rv = NS_OK;
  nsCOMPtr<nsIGConfService> gconf =
    do_GetService(NS_GCONFSERVICE_CONTRACTID, &rv);
  if (NS_SUCCEEDED(rv) && gconf)
    gconf->GetBool(NS_LITERAL_CSTRING(sGconfAccessibilityKey), &sShouldEnable);

  return sShouldEnable;
}
} // namespace a11y
} // namespace mozilla