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39
40
41
42 #include "dbusconnection_p.h"
43
44 #include <QtDBus/QDBusMessage>
45 #include <QtDBus/QDBusServiceWatcher>
46 #include <qdebug.h>
47
48 #include <QDBusConnectionInterface>
49 #include "bus_interface.h"
50
51 #include <QtGui/qguiapplication.h>
52 #include <qpa/qplatformnativeinterface.h>
53
54 QT_BEGIN_NAMESPACE
55
56 /* note: do not change these to QStringLiteral;
57 we are unloaded before QtDBus is done using the strings.
58 */
59 #define A11Y_SERVICE QLatin1String("org.a11y.Bus")
60 #define A11Y_PATH QLatin1String("/org/a11y/bus")
61
62 /*!
63 \class DBusConnection
64 \internal
65 \brief Connects to the accessibility dbus.
66
67 This is usually a different bus from the session bus.
68 */
DBusConnection(QObject * parent)69 DBusConnection::DBusConnection(QObject *parent)
70 : QObject(parent), m_a11yConnection(QString()), m_enabled(false)
71 {
72 // Start monitoring if "org.a11y.Bus" is registered as DBus service.
73 QDBusConnection c = QDBusConnection::sessionBus();
74 if (!c.isConnected()) {
75 return;
76 }
77
78 dbusWatcher = new QDBusServiceWatcher(A11Y_SERVICE, c, QDBusServiceWatcher::WatchForRegistration, this);
79 connect(dbusWatcher, SIGNAL(serviceRegistered(QString)), this, SLOT(serviceRegistered()));
80
81 // If it is registered already, setup a11y right away
82 if (c.interface()->isServiceRegistered(A11Y_SERVICE))
83 serviceRegistered();
84
85 // In addition try if there is an xatom exposing the bus address, this allows applications run as root to work
86 QString address = getAddressFromXCB();
87 if (!address.isEmpty()) {
88 m_enabled = true;
89 connectA11yBus(address);
90 }
91 }
92
getAddressFromXCB()93 QString DBusConnection::getAddressFromXCB()
94 {
95 QGuiApplication *app = qobject_cast<QGuiApplication *>(QCoreApplication::instance());
96 if (!app)
97 return QString();
98 QPlatformNativeInterface *platformNativeInterface = app->platformNativeInterface();
99 QByteArray *addressByteArray = reinterpret_cast<QByteArray*>(
100 platformNativeInterface->nativeResourceForIntegration(QByteArrayLiteral("AtspiBus")));
101 if (addressByteArray) {
102 QString address = QString::fromLatin1(*addressByteArray);
103 delete addressByteArray;
104 return address;
105 }
106 return QString();
107 }
108
109 // We have the a11y registry on the session bus.
110 // Subscribe to updates about a11y enabled state.
111 // Find out the bus address
serviceRegistered()112 void DBusConnection::serviceRegistered()
113 {
114 // listen to enabled changes
115 QDBusConnection c = QDBusConnection::sessionBus();
116 OrgA11yStatusInterface *a11yStatus = new OrgA11yStatusInterface(A11Y_SERVICE, A11Y_PATH, c, this);
117
118 //The variable was introduced because on some embedded platforms there are custom accessibility
119 //clients which don't set Status.ScreenReaderEnabled to true. The variable is also useful for
120 //debugging.
121 static const bool a11yAlwaysOn = qEnvironmentVariableIsSet("QT_LINUX_ACCESSIBILITY_ALWAYS_ON");
122
123 bool enabled = a11yAlwaysOn || a11yStatus->screenReaderEnabled() || a11yStatus->isEnabled();
124
125 if (enabled != m_enabled) {
126 m_enabled = enabled;
127 if (m_a11yConnection.isConnected()) {
128 emit enabledChanged(m_enabled);
129 } else {
130 QDBusConnection c = QDBusConnection::sessionBus();
131 QDBusMessage m = QDBusMessage::createMethodCall(QLatin1String("org.a11y.Bus"),
132 QLatin1String("/org/a11y/bus"),
133 QLatin1String("org.a11y.Bus"), QLatin1String("GetAddress"));
134 c.callWithCallback(m, this, SLOT(connectA11yBus(QString)), SLOT(dbusError(QDBusError)));
135 }
136 }
137
138 // connect(a11yStatus, ); QtDbus doesn't support notifications for property changes yet
139 }
140
serviceUnregistered()141 void DBusConnection::serviceUnregistered()
142 {
143 emit enabledChanged(false);
144 }
145
connectA11yBus(const QString & address)146 void DBusConnection::connectA11yBus(const QString &address)
147 {
148 if (address.isEmpty()) {
149 qWarning("Could not find Accessibility DBus address.");
150 return;
151 }
152 m_a11yConnection = QDBusConnection(QDBusConnection::connectToBus(address, QLatin1String("a11y")));
153
154 if (m_enabled)
155 emit enabledChanged(true);
156 }
157
dbusError(const QDBusError & error)158 void DBusConnection::dbusError(const QDBusError &error)
159 {
160 qWarning() << "Accessibility encountered a DBus error:" << error;
161 }
162
163 /*!
164 Returns the DBus connection that got established.
165 Or an invalid connection if not yet connected.
166 */
connection() const167 QDBusConnection DBusConnection::connection() const
168 {
169 return m_a11yConnection;
170 }
171
172 QT_END_NAMESPACE
173