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