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 "nsIGSettingsService.h"
  11 #include "nsMai.h"
  12 #include "AtkSocketAccessible.h"
  13 #include "prenv.h"
  14 #include "prlink.h"
  15
  16 #ifdef MOZ_ENABLE_DBUS
  17 #  include <dbus/dbus.h>
  18 #endif
  19 #include <gtk/gtk.h>
  20
  21 #ifdef MOZ_WIDGET_GTK
  22 extern "C" __attribute__((weak, visibility("default"))) int
  23 atk_bridge_adaptor_init(int*, char**[]);
  24 #endif
  25
  26 using namespace mozilla;
  27 using namespace mozilla::a11y;
  28
  29 int atkMajorVersion = 1, atkMinorVersion = 12, atkMicroVersion = 0;
  30
  31 GType (*gAtkTableCellGetTypeFunc)();
  32
  33 extern "C" {
  34 typedef GType (*AtkGetTypeType)(void);
  35 typedef void (*GnomeAccessibilityInit)(void);
  36 typedef void (*GnomeAccessibilityShutdown)(void);
  37 }
  38
  39 static PRLibrary* sATKLib = nullptr;
  40 static const char sATKLibName[] = "libatk-1.0.so.0";
  41 static const char sATKHyperlinkImplGetTypeSymbol[] =
  42     "atk_hyperlink_impl_get_type";
  43
  44 gboolean toplevel_event_watcher(GSignalInvocationHint*, guint, const GValue*,
  45                                 gpointer);
  46 static bool sToplevel_event_hook_added = false;
  47 static gulong sToplevel_show_hook = 0;
  48 static gulong sToplevel_hide_hook = 0;
  49
  50 GType g_atk_hyperlink_impl_type = G_TYPE_INVALID;
  51
  52 struct GnomeAccessibilityModule {
  53   const char* libName;
  54   PRLibrary* lib;
  55   const char* initName;
  56   GnomeAccessibilityInit init;
  57   const char* shutdownName;
  58   GnomeAccessibilityShutdown shutdown;
  59 };
  60
  61 static GnomeAccessibilityModule sAtkBridge = {
  62 #ifdef AIX
  63     "libatk-bridge.a(libatk-bridge.so.0)", nullptr,
  64 #else
  65     "libatk-bridge.so", nullptr,
  66 #endif
  67     "gnome_accessibility_module_init",     nullptr,
  68     "gnome_accessibility_module_shutdown", nullptr};
  69
  70 static nsresult LoadGtkModule(GnomeAccessibilityModule& aModule) {
  71   NS_ENSURE_ARG(aModule.libName);
  72
  73   if (!(aModule.lib = PR_LoadLibrary(aModule.libName))) {
  74     // try to load the module with "gtk-2.0/modules" appended
  75     char* curLibPath = PR_GetLibraryPath();
  76     nsAutoCString libPath(curLibPath);
  77 #if defined(LINUX) && defined(__x86_64__)
  78     libPath.AppendLiteral(":/usr/lib64:/usr/lib");
  79 #else
  80     libPath.AppendLiteral(":/usr/lib");
  81 #endif
  82     PR_FreeLibraryName(curLibPath);
  83
  84     int16_t loc1 = 0, loc2 = 0;
  85     int16_t subLen = 0;
  86     while (loc2 >= 0) {
  87       loc2 = libPath.FindChar(':', loc1);
  88       if (loc2 < 0)
  89         subLen = libPath.Length() - loc1;
  90       else
  91         subLen = loc2 - loc1;
  92       nsAutoCString sub(Substring(libPath, loc1, subLen));
  93       sub.AppendLiteral("/gtk-3.0/modules/");
  94       sub.Append(aModule.libName);
  95       aModule.lib = PR_LoadLibrary(sub.get());
  96       if (aModule.lib) break;
  97
  98       loc1 = loc2 + 1;
  99     }
 100     if (!aModule.lib) return NS_ERROR_FAILURE;
 101   }
 102
 103   // we have loaded the library, try to get the function ptrs
 104   if (!(aModule.init = PR_FindFunctionSymbol(aModule.lib, aModule.initName)) ||
 105       !(aModule.shutdown =
 106             PR_FindFunctionSymbol(aModule.lib, aModule.shutdownName))) {
 107     // fail, :(
 108     PR_UnloadLibrary(aModule.lib);
 109     aModule.lib = nullptr;
 110     return NS_ERROR_FAILURE;
 111   }
 112   return NS_OK;
 113 }
 114
 115 void a11y::PlatformInit() {
 116   if (!ShouldA11yBeEnabled()) return;
 117
 118   sATKLib = PR_LoadLibrary(sATKLibName);
 119   if (!sATKLib) return;
 120
 121   AtkGetTypeType pfn_atk_hyperlink_impl_get_type =
 122       (AtkGetTypeType)PR_FindFunctionSymbol(sATKLib,
 123                                             sATKHyperlinkImplGetTypeSymbol);
 124   if (pfn_atk_hyperlink_impl_get_type)
 125     g_atk_hyperlink_impl_type = pfn_atk_hyperlink_impl_get_type();
 126
 127   AtkGetTypeType pfn_atk_socket_get_type =
 128       (AtkGetTypeType)PR_FindFunctionSymbol(
 129           sATKLib, AtkSocketAccessible::sATKSocketGetTypeSymbol);
 130   if (pfn_atk_socket_get_type) {
 131     AtkSocketAccessible::g_atk_socket_type = pfn_atk_socket_get_type();
 132     AtkSocketAccessible::g_atk_socket_embed =
 133         (AtkSocketEmbedType)PR_FindFunctionSymbol(
 134             sATKLib, AtkSocketAccessible ::sATKSocketEmbedSymbol);
 135     AtkSocketAccessible::gCanEmbed =
 136         AtkSocketAccessible::g_atk_socket_type != G_TYPE_INVALID &&
 137         AtkSocketAccessible::g_atk_socket_embed;
 138   }
 139
 140   gAtkTableCellGetTypeFunc =
 141       (GType(*)())PR_FindFunctionSymbol(sATKLib, "atk_table_cell_get_type");
 142
 143   const char* (*atkGetVersion)() =
 144       (const char* (*)())PR_FindFunctionSymbol(sATKLib, "atk_get_version");
 145   if (atkGetVersion) {
 146     const char* version = atkGetVersion();
 147     if (version) {
 148       char* endPtr = nullptr;
 149       atkMajorVersion = strtol(version, &endPtr, 10);
 150       if (atkMajorVersion != 0L) {
 151         atkMinorVersion = strtol(endPtr + 1, &endPtr, 10);
 152         if (atkMinorVersion != 0L)
 153           atkMicroVersion = strtol(endPtr + 1, &endPtr, 10);
 154       }
 155     }
 156   }
 157
 158   // Initialize the MAI Utility class, it will overwrite gail_util.
 159   g_type_class_unref(g_type_class_ref(mai_util_get_type()));
 160
 161   // Init atk-bridge now
 162   PR_SetEnv("NO_AT_BRIDGE=0");
 163 #ifdef MOZ_WIDGET_GTK
 164   if (atk_bridge_adaptor_init) {
 165     atk_bridge_adaptor_init(nullptr, nullptr);
 166   } else
 167 #endif
 168   {
 169     nsresult rv = LoadGtkModule(sAtkBridge);
 170     if (NS_SUCCEEDED(rv)) {
 171       (*sAtkBridge.init)();
 172     }
 173   }
 174
 175   if (!sToplevel_event_hook_added) {
 176     sToplevel_event_hook_added = true;
 177     sToplevel_show_hook = g_signal_add_emission_hook(
 178         g_signal_lookup("show", GTK_TYPE_WINDOW), 0, toplevel_event_watcher,
 179         reinterpret_cast<gpointer>(nsIAccessibleEvent::EVENT_SHOW), nullptr);
 180     sToplevel_hide_hook = g_signal_add_emission_hook(
 181         g_signal_lookup("hide", GTK_TYPE_WINDOW), 0, toplevel_event_watcher,
 182         reinterpret_cast<gpointer>(nsIAccessibleEvent::EVENT_HIDE), nullptr);
 183   }
 184 }
 185
 186 void a11y::PlatformShutdown() {
 187   if (sToplevel_event_hook_added) {
 188     sToplevel_event_hook_added = false;
 189     g_signal_remove_emission_hook(g_signal_lookup("show", GTK_TYPE_WINDOW),
 190                                   sToplevel_show_hook);
 191     g_signal_remove_emission_hook(g_signal_lookup("hide", GTK_TYPE_WINDOW),
 192                                   sToplevel_hide_hook);
 193   }
 194
 195   if (sAtkBridge.lib) {
 196     // Do not shutdown/unload atk-bridge,
 197     // an exit function registered will take care of it
 198     // if (sAtkBridge.shutdown)
 199     //     (*sAtkBridge.shutdown)();
 200     // PR_UnloadLibrary(sAtkBridge.lib);
 201     sAtkBridge.lib = nullptr;
 202     sAtkBridge.init = nullptr;
 203     sAtkBridge.shutdown = nullptr;
 204   }
 205   // if (sATKLib) {
 206   //     PR_UnloadLibrary(sATKLib);
 207   //     sATKLib = nullptr;
 208   // }
 209 }
 210
 211 static const char sAccEnv[] = "GNOME_ACCESSIBILITY";
 212 #ifdef MOZ_ENABLE_DBUS
 213 static DBusPendingCall* sPendingCall = nullptr;
 214 #endif
 215
 216 void a11y::PreInit() {
 217 #ifdef MOZ_ENABLE_DBUS
 218   static bool sChecked = FALSE;
 219   if (sChecked) return;
 220
 221   sChecked = TRUE;
 222
 223   // dbus is only checked if GNOME_ACCESSIBILITY is unset
 224   // also make sure that a session bus address is available to prevent dbus from
 225   // starting a new one.  Dbus confuses the test harness when it creates a new
 226   // process (see bug 693343)
 227   if (PR_GetEnv(sAccEnv) || !PR_GetEnv("DBUS_SESSION_BUS_ADDRESS")) return;
 228
 229   DBusConnection* bus = dbus_bus_get(DBUS_BUS_SESSION, nullptr);
 230   if (!bus) return;
 231
 232   dbus_connection_set_exit_on_disconnect(bus, FALSE);
 233
 234   static const char* iface = "org.a11y.Status";
 235   static const char* member = "IsEnabled";
 236   DBusMessage* message;
 237   message =
 238       dbus_message_new_method_call("org.a11y.Bus", "/org/a11y/bus",
 239                                    "org.freedesktop.DBus.Properties", "Get");
 240   if (!message) goto dbus_done;
 241
 242   dbus_message_append_args(message, DBUS_TYPE_STRING, &iface, DBUS_TYPE_STRING,
 243                            &member, DBUS_TYPE_INVALID);
 244   dbus_connection_send_with_reply(bus, message, &sPendingCall, 1000);
 245   dbus_message_unref(message);
 246
 247 dbus_done:
 248   dbus_connection_unref(bus);
 249 #endif
 250 }
 251
 252 bool a11y::ShouldA11yBeEnabled() {
 253   static bool sChecked = false, sShouldEnable = false;
 254   if (sChecked) return sShouldEnable;
 255
 256   sChecked = true;
 257
 258   EPlatformDisabledState disabledState = PlatformDisabledState();
 259   if (disabledState == ePlatformIsDisabled) return sShouldEnable = false;
 260
 261   // check if accessibility enabled/disabled by environment variable
 262   const char* envValue = PR_GetEnv(sAccEnv);
 263   if (envValue) return sShouldEnable = !!atoi(envValue);
 264
 265 #ifdef MOZ_ENABLE_DBUS
 266   PreInit();
 267   bool dbusSuccess = false;
 268   DBusMessage* reply = nullptr;
 269   if (!sPendingCall) goto dbus_done;
 270
 271   dbus_pending_call_block(sPendingCall);
 272   reply = dbus_pending_call_steal_reply(sPendingCall);
 273   dbus_pending_call_unref(sPendingCall);
 274   sPendingCall = nullptr;
 275   if (!reply ||
 276       dbus_message_get_type(reply) != DBUS_MESSAGE_TYPE_METHOD_RETURN ||
 277       strcmp(dbus_message_get_signature(reply), DBUS_TYPE_VARIANT_AS_STRING))
 278     goto dbus_done;
 279
 280   DBusMessageIter iter, iter_variant, iter_struct;
 281   dbus_bool_t dResult;
 282   dbus_message_iter_init(reply, &iter);
 283   dbus_message_iter_recurse(&iter, &iter_variant);
 284   switch (dbus_message_iter_get_arg_type(&iter_variant)) {
 285     case DBUS_TYPE_STRUCT:
 286       // at-spi2-core 2.2.0-2.2.1 had a bug where it returned a struct
 287       dbus_message_iter_recurse(&iter_variant, &iter_struct);
 288       if (dbus_message_iter_get_arg_type(&iter_struct) == DBUS_TYPE_BOOLEAN) {
 289         dbus_message_iter_get_basic(&iter_struct, &dResult);
 290         sShouldEnable = dResult;
 291         dbusSuccess = true;
 292       }
 293
 294       break;
 295     case DBUS_TYPE_BOOLEAN:
 296       dbus_message_iter_get_basic(&iter_variant, &dResult);
 297       sShouldEnable = dResult;
 298       dbusSuccess = true;
 299       break;
 300     default:
 301       break;
 302   }
 303
 304 dbus_done:
 305   if (reply) dbus_message_unref(reply);
 306
 307   if (dbusSuccess) return sShouldEnable;
 308 #endif
 309
 310 // check GSettings
 311 #define GSETINGS_A11Y_INTERFACE "org.gnome.desktop.interface"
 312 #define GSETINGS_A11Y_KEY "toolkit-accessibility"
 313   nsCOMPtr<nsIGSettingsService> gsettings =
 314       do_GetService(NS_GSETTINGSSERVICE_CONTRACTID);
 315   nsCOMPtr<nsIGSettingsCollection> a11y_settings;
 316
 317   if (gsettings) {
 318     gsettings->GetCollectionForSchema(nsLiteralCString(GSETINGS_A11Y_INTERFACE),
 319                                       getter_AddRefs(a11y_settings));
 320     if (a11y_settings) {
 321       a11y_settings->GetBoolean(nsLiteralCString(GSETINGS_A11Y_KEY),
 322                                 &sShouldEnable);
 323     }
 324   }
 325
 326   return sShouldEnable;
 327 }