accessible/atk/Platform.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "Platform.h"
   8
   9 #include "nsIAccessibleEvent.h"
  10 #include "nsIGConfService.h"
  11 #include "nsIServiceManager.h"
  12 #include "nsMai.h"
  13 #include "AtkSocketAccessible.h"
  14 #include "prenv.h"
  15 #include "prlink.h"
  16
  17 #ifdef MOZ_ENABLE_DBUS
  18 #include <dbus/dbus.h>
  19 #endif
  20 #include <gtk/gtk.h>
  21 #if (MOZ_WIDGET_GTK == 3)
  22 #include <atk-bridge.h>
  23 #endif
  24
  25 using namespace mozilla;
  26 using namespace mozilla::a11y;
  27
  28 int atkMajorVersion = 1, atkMinorVersion = 12;
  29
  30 extern "C" {
  31 typedef GType (* AtkGetTypeType) (void);
  32 typedef void (*GnomeAccessibilityInit) (void);
  33 typedef void (*GnomeAccessibilityShutdown) (void);
  34 }
  35
  36 static PRLibrary* sATKLib = nullptr;
  37 static const char sATKLibName[] = "libatk-1.0.so.0";
  38 static const char sATKHyperlinkImplGetTypeSymbol[] =
  39   "atk_hyperlink_impl_get_type";
  40
  41 gboolean toplevel_event_watcher(GSignalInvocationHint*, guint, const GValue*,
  42                                 gpointer);
  43 static bool sToplevel_event_hook_added = false;
  44 static gulong sToplevel_show_hook = 0;
  45 static gulong sToplevel_hide_hook = 0;
  46
  47 GType g_atk_hyperlink_impl_type = G_TYPE_INVALID;
  48
  49 #if (MOZ_WIDGET_GTK == 2)
  50 struct GnomeAccessibilityModule
  51 {
  52     const char *libName;
  53     PRLibrary *lib;
  54     const char *initName;
  55     GnomeAccessibilityInit init;
  56     const char *shutdownName;
  57     GnomeAccessibilityShutdown shutdown;
  58 };
  59
  60 static GnomeAccessibilityModule sAtkBridge = {
  61 #ifdef AIX
  62     "libatk-bridge.a(libatk-bridge.so.0)", nullptr,
  63 #else
  64     "libatk-bridge.so", nullptr,
  65 #endif
  66     "gnome_accessibility_module_init", nullptr,
  67     "gnome_accessibility_module_shutdown", nullptr
  68 };
  69
  70 static GnomeAccessibilityModule sGail = {
  71     "libgail.so", nullptr,
  72     "gnome_accessibility_module_init", nullptr,
  73     "gnome_accessibility_module_shutdown", nullptr
  74 };
  75
  76 static nsresult
  77 LoadGtkModule(GnomeAccessibilityModule& aModule)
  78 {
  79     NS_ENSURE_ARG(aModule.libName);
  80
  81     if (!(aModule.lib = PR_LoadLibrary(aModule.libName))) {
  82         //try to load the module with "gtk-2.0/modules" appended
  83         char *curLibPath = PR_GetLibraryPath();
  84         nsAutoCString libPath(curLibPath);
  85 #if defined(LINUX) && defined(__x86_64__)
  86         libPath.AppendLiteral(":/usr/lib64:/usr/lib");
  87 #else
  88         libPath.AppendLiteral(":/usr/lib");
  89 #endif
  90         PR_FreeLibraryName(curLibPath);
  91
  92         int16_t loc1 = 0, loc2 = 0;
  93         int16_t subLen = 0;
  94         while (loc2 >= 0) {
  95             loc2 = libPath.FindChar(':', loc1);
  96             if (loc2 < 0)
  97                 subLen = libPath.Length() - loc1;
  98             else
  99                 subLen = loc2 - loc1;
 100             nsAutoCString sub(Substring(libPath, loc1, subLen));
 101             sub.AppendLiteral("/gtk-2.0/modules/");
 102             sub.Append(aModule.libName);
 103             aModule.lib = PR_LoadLibrary(sub.get());
 104             if (aModule.lib)
 105                 break;
 106
 107             loc1 = loc2+1;
 108         }
 109         if (!aModule.lib)
 110             return NS_ERROR_FAILURE;
 111     }
 112
 113     //we have loaded the library, try to get the function ptrs
 114     if (!(aModule.init = PR_FindFunctionSymbol(aModule.lib,
 115                                                aModule.initName)) ||
 116         !(aModule.shutdown = PR_FindFunctionSymbol(aModule.lib,
 117                                                    aModule.shutdownName))) {
 118
 119         //fail, :(
 120         PR_UnloadLibrary(aModule.lib);
 121         aModule.lib = nullptr;
 122         return NS_ERROR_FAILURE;
 123     }
 124     return NS_OK;
 125 }
 126 #endif // (MOZ_WIDGET_GTK == 2)
 127
 128 void
 129 a11y::PlatformInit()
 130 {
 131   if (!ShouldA11yBeEnabled())
 132     return;
 133
 134   sATKLib = PR_LoadLibrary(sATKLibName);
 135   if (!sATKLib)
 136     return;
 137
 138   AtkGetTypeType pfn_atk_hyperlink_impl_get_type =
 139     (AtkGetTypeType) PR_FindFunctionSymbol(sATKLib, sATKHyperlinkImplGetTypeSymbol);
 140   if (pfn_atk_hyperlink_impl_get_type)
 141     g_atk_hyperlink_impl_type = pfn_atk_hyperlink_impl_get_type();
 142
 143   AtkGetTypeType pfn_atk_socket_get_type = (AtkGetTypeType)
 144     PR_FindFunctionSymbol(sATKLib, AtkSocketAccessible::sATKSocketGetTypeSymbol);
 145   if (pfn_atk_socket_get_type) {
 146     AtkSocketAccessible::g_atk_socket_type = pfn_atk_socket_get_type();
 147     AtkSocketAccessible::g_atk_socket_embed = (AtkSocketEmbedType)
 148       PR_FindFunctionSymbol(sATKLib, AtkSocketAccessible ::sATKSocketEmbedSymbol);
 149     AtkSocketAccessible::gCanEmbed =
 150       AtkSocketAccessible::g_atk_socket_type != G_TYPE_INVALID &&
 151       AtkSocketAccessible::g_atk_socket_embed;
 152   }
 153
 154   const char* (*atkGetVersion)() =
 155     (const char* (*)()) PR_FindFunctionSymbol(sATKLib, "atk_get_version");
 156   if (atkGetVersion) {
 157     const char* version = atkGetVersion();
 158     if (version) {
 159       char* endPtr = nullptr;
 160       atkMajorVersion = strtol(version, &endPtr, 10);
 161       if (*endPtr == '.')
 162         atkMinorVersion = strtol(endPtr + 1, &endPtr, 10);
 163     }
 164   }
 165
 166 #if (MOZ_WIDGET_GTK == 2)
 167   // Load and initialize gail library.
 168   nsresult rv = LoadGtkModule(sGail);
 169   if (NS_SUCCEEDED(rv))
 170     (*sGail.init)();
 171 #endif
 172
 173   // Initialize the MAI Utility class, it will overwrite gail_util.
 174   g_type_class_unref(g_type_class_ref(mai_util_get_type()));
 175
 176   // Init atk-bridge now
 177   PR_SetEnv("NO_AT_BRIDGE=0");
 178 #if (MOZ_WIDGET_GTK == 2)
 179   rv = LoadGtkModule(sAtkBridge);
 180   if (NS_SUCCEEDED(rv)) {
 181     (*sAtkBridge.init)();
 182   }
 183 #else
 184   atk_bridge_adaptor_init(nullptr, nullptr);
 185 #endif
 186
 187   if (!sToplevel_event_hook_added) {
 188     sToplevel_event_hook_added = true;
 189     sToplevel_show_hook =
 190       g_signal_add_emission_hook(g_signal_lookup("show", GTK_TYPE_WINDOW),
 191                                  0, toplevel_event_watcher,
 192                                  reinterpret_cast<gpointer>(nsIAccessibleEvent::EVENT_SHOW),
 193                                  nullptr);
 194     sToplevel_hide_hook =
 195       g_signal_add_emission_hook(g_signal_lookup("hide", GTK_TYPE_WINDOW), 0,
 196                                  toplevel_event_watcher,
 197                                  reinterpret_cast<gpointer>(nsIAccessibleEvent::EVENT_HIDE),
 198                                  nullptr);
 199   }
 200 }
 201
 202 void
 203 a11y::PlatformShutdown()
 204 {
 205     if (sToplevel_event_hook_added) {
 206       sToplevel_event_hook_added = false;
 207       g_signal_remove_emission_hook(g_signal_lookup("show", GTK_TYPE_WINDOW),
 208                                     sToplevel_show_hook);
 209       g_signal_remove_emission_hook(g_signal_lookup("hide", GTK_TYPE_WINDOW),
 210                                     sToplevel_hide_hook);
 211     }
 212
 213 #if (MOZ_WIDGET_GTK == 2)
 214     if (sAtkBridge.lib) {
 215         // Do not shutdown/unload atk-bridge,
 216         // an exit function registered will take care of it
 217         // if (sAtkBridge.shutdown)
 218         //     (*sAtkBridge.shutdown)();
 219         // PR_UnloadLibrary(sAtkBridge.lib);
 220         sAtkBridge.lib = nullptr;
 221         sAtkBridge.init = nullptr;
 222         sAtkBridge.shutdown = nullptr;
 223     }
 224     if (sGail.lib) {
 225         // Do not shutdown gail because
 226         // 1) Maybe it's not init-ed by us. e.g. GtkEmbed
 227         // 2) We need it to avoid assert in spi_atk_tidy_windows
 228         // if (sGail.shutdown)
 229         //   (*sGail.shutdown)();
 230         // PR_UnloadLibrary(sGail.lib);
 231         sGail.lib = nullptr;
 232         sGail.init = nullptr;
 233         sGail.shutdown = nullptr;
 234     }
 235 #endif
 236     // if (sATKLib) {
 237     //     PR_UnloadLibrary(sATKLib);
 238     //     sATKLib = nullptr;
 239     // }
 240 }
 241
 242   static const char sAccEnv [] = "GNOME_ACCESSIBILITY";
 243 #ifdef MOZ_ENABLE_DBUS
 244 static DBusPendingCall *sPendingCall = nullptr;
 245 #endif
 246
 247 void
 248 a11y::PreInit()
 249 {
 250 #ifdef MOZ_ENABLE_DBUS
 251   static bool sChecked = FALSE;
 252   if (sChecked)
 253     return;
 254
 255   sChecked = TRUE;
 256
 257   // dbus is only checked if GNOME_ACCESSIBILITY is unset
 258   // also make sure that a session bus address is available to prevent dbus from
 259   // starting a new one.  Dbus confuses the test harness when it creates a new
 260   // process (see bug 693343)
 261   if (PR_GetEnv(sAccEnv) || !PR_GetEnv("DBUS_SESSION_BUS_ADDRESS"))
 262     return;
 263
 264   DBusConnection* bus = dbus_bus_get(DBUS_BUS_SESSION, nullptr);
 265   if (!bus)
 266     return;
 267
 268   dbus_connection_set_exit_on_disconnect(bus, FALSE);
 269
 270   static const char* iface = "org.a11y.Status";
 271   static const char* member = "IsEnabled";
 272   DBusMessage *message;
 273   message = dbus_message_new_method_call("org.a11y.Bus", "/org/a11y/bus",
 274                                          "org.freedesktop.DBus.Properties",
 275                                          "Get");
 276   if (!message)
 277     goto dbus_done;
 278
 279   dbus_message_append_args(message, DBUS_TYPE_STRING, &iface,
 280                            DBUS_TYPE_STRING, &member, DBUS_TYPE_INVALID);
 281   dbus_connection_send_with_reply(bus, message, &sPendingCall, 1000);
 282   dbus_message_unref(message);
 283
 284 dbus_done:
 285   dbus_connection_unref(bus);
 286 #endif
 287 }
 288
 289 bool
 290 a11y::ShouldA11yBeEnabled()
 291 {
 292   static bool sChecked = false, sShouldEnable = false;
 293   if (sChecked)
 294     return sShouldEnable;
 295
 296   sChecked = true;
 297
 298   EPlatformDisabledState disabledState = PlatformDisabledState();
 299   if (disabledState == ePlatformIsDisabled)
 300     return sShouldEnable = false;
 301
 302   // check if accessibility enabled/disabled by environment variable
 303   const char* envValue = PR_GetEnv(sAccEnv);
 304   if (envValue)
 305     return sShouldEnable = !!atoi(envValue);
 306
 307 #ifdef MOZ_ENABLE_DBUS
 308   PreInit();
 309   bool dbusSuccess = false;
 310   DBusMessage *reply = nullptr;
 311   if (!sPendingCall)
 312     goto dbus_done;
 313
 314   dbus_pending_call_block(sPendingCall);
 315   reply = dbus_pending_call_steal_reply(sPendingCall);
 316   dbus_pending_call_unref(sPendingCall);
 317   sPendingCall = nullptr;
 318   if (!reply ||
 319       dbus_message_get_type(reply) != DBUS_MESSAGE_TYPE_METHOD_RETURN ||
 320       strcmp(dbus_message_get_signature (reply), DBUS_TYPE_VARIANT_AS_STRING))
 321     goto dbus_done;
 322
 323   DBusMessageIter iter, iter_variant, iter_struct;
 324   dbus_bool_t dResult;
 325   dbus_message_iter_init(reply, &iter);
 326   dbus_message_iter_recurse (&iter, &iter_variant);
 327   switch (dbus_message_iter_get_arg_type(&iter_variant)) {
 328     case DBUS_TYPE_STRUCT:
 329       // at-spi2-core 2.2.0-2.2.1 had a bug where it returned a struct
 330       dbus_message_iter_recurse(&iter_variant, &iter_struct);
 331       if (dbus_message_iter_get_arg_type(&iter_struct) == DBUS_TYPE_BOOLEAN) {
 332         dbus_message_iter_get_basic(&iter_struct, &dResult);
 333         sShouldEnable = dResult;
 334         dbusSuccess = true;
 335       }
 336
 337       break;
 338     case DBUS_TYPE_BOOLEAN:
 339       dbus_message_iter_get_basic(&iter_variant, &dResult);
 340       sShouldEnable = dResult;
 341       dbusSuccess = true;
 342       break;
 343     default:
 344       break;
 345   }
 346
 347 dbus_done:
 348   if (reply)
 349     dbus_message_unref(reply);
 350
 351   if (dbusSuccess)
 352     return sShouldEnable;
 353 #endif
 354
 355   //check gconf-2 setting
 356 static const char sGconfAccessibilityKey[] =
 357     "/desktop/gnome/interface/accessibility";
 358   nsresult rv = NS_OK;
 359   nsCOMPtr<nsIGConfService> gconf =
 360     do_GetService(NS_GCONFSERVICE_CONTRACTID, &rv);
 361   if (NS_SUCCEEDED(rv) && gconf)
 362     gconf->GetBool(NS_LITERAL_CSTRING(sGconfAccessibilityKey), &sShouldEnable);
 363
 364   return sShouldEnable;
 365 }