Gypsy plugin: introduce plugin parameters

Previously the plugin was taking the device name from a hardcoded path
in the GConf parameters.
This patch adds the possibility to specify the device in two ways:
* use 'gconfKey' parameter to specify the GConf key, that should be
  used to extract the device name;
* use 'deviceName' parameter to specify the device name directly.

If none of these parameters is specified, the old behavior is used,
i.e. the plugin uses the hardcoded GConf key to try to extract the
device name.

Task-number: QTBUG-74995
Change-Id: I7c911630a2d367310e62764a1660171a6856e27b
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>
(cherry picked from commit cac741dd3a13bb724b9e16877ea5b3b404e0ad1f)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

3 files changed, 58 insertions, 21 deletions

diff --git a/src/plugins/position/gypsy/qgeopositioninfosourcefactory_gypsy.cpp b/src/plugins/position/gypsy/qgeopositioninfosourcefactory_gypsy.cpp
index 84fa1a5c..be7634cd 100644
--- a/src/plugins/position/gypsy/qgeopositioninfosourcefactory_gypsy.cpp
+++ b/src/plugins/position/gypsy/qgeopositioninfosourcefactory_gypsy.cpp
@@ -51,7 +51,7 @@ QGeoSatelliteInfoSource *QGeoPositionInfoSourceFactoryGypsy::satelliteInfoSource
 {
     Q_UNUSED(parameters)
     QGeoSatelliteInfoSourceGypsy *src = new QGeoSatelliteInfoSourceGypsy(parent);
-    if (src->init() < 0) {
+    if (src->init(parameters) < 0) {
         delete src;
         src = nullptr;
     }
diff --git a/src/plugins/position/gypsy/qgeosatelliteinfosource_gypsy.cpp b/src/plugins/position/gypsy/qgeosatelliteinfosource_gypsy.cpp
index c473c3f3..b7f91131 100644
--- a/src/plugins/position/gypsy/qgeosatelliteinfosource_gypsy.cpp
+++ b/src/plugins/position/gypsy/qgeosatelliteinfosource_gypsy.cpp
@@ -43,11 +43,15 @@
 #include <QDebug>
 #endif
 #include <QFile>
+#include <QVariantMap>
 
 QT_BEGIN_NAMESPACE
 
 #define UPDATE_TIMEOUT_COLD_START 120000
 
+static const auto deviceNameParameter = "deviceName";
+static const auto gconfKeyParameter = "gconfKey";
+static const auto defaultGconfKey = "/apps/geoclue/master/org.freedesktop.Geoclue.GPSDevice";
 
 // Callback function for 'satellites-changed' -signal
 static void satellites_changed (GypsySatellite *satellite,
@@ -231,43 +235,70 @@ void QGeoSatelliteInfoSourceGypsy::satellitesChanged(GypsySatellite *satellite,
     }
 }
 
-int QGeoSatelliteInfoSourceGypsy::init()
+QString QGeoSatelliteInfoSourceGypsy::extractDeviceNameFromParameters(const QVariantMap &parameters) const
+{
+    // The logic is as follows:
+    // 1. If the deviceNameParameter is specified, its value is used to get the
+    // device name.
+    // 2. If the gconfKeyParameter is specified, its value is used as a key to
+    // extract the device name from GConf.
+    // 3. If nothing is specified, defaultGconfKey is used as a key to extract
+    // the device name from GConf.
+    if (parameters.contains(deviceNameParameter))
+        return parameters.value(deviceNameParameter).toString();
+
+    QString gconfKey = parameters.value(gconfKeyParameter).toString();
+    if (gconfKey.isEmpty())
+        gconfKey = defaultGconfKey;
+
+    if (!m_engine)
+        return QString();
+
+    GConfClient *client = m_engine->eng_gconf_client_get_default();
+    if (!client)
+        return QString();
+
+    gchar *device_name = m_engine->eng_gconf_client_get_string(client,
+                                                               gconfKey.toLatin1().constData(),
+                                                               nullptr);
+    g_object_unref(client);
+
+    const QString deviceName = QString::fromLatin1(device_name);
+    m_engine->eng_g_free(device_name);
+
+    return deviceName;
+}
+
+int QGeoSatelliteInfoSourceGypsy::init(const QVariantMap parameters)
 {
     GError *error = NULL;
     char *path;
-    GConfClient *client;
-    gchar *device_name;
 
 #if !GLIB_CHECK_VERSION(2, 36, 0)
     g_type_init (); // this function was deprecated in glib 2.36
 #endif
     createEngine();
 
-    client = m_engine->eng_gconf_client_get_default();
-    if (!client) {
-        qWarning ("QGeoSatelliteInfoSourceGypsy client creation failed.");
-        return -1;
-    }
-    device_name = m_engine->eng_gconf_client_get_string(client, "/apps/geoclue/master/org.freedesktop.Geoclue.GPSDevice", NULL);
-    g_object_unref(client);
-    QString deviceName(QString::fromLatin1(device_name));
+    const QString deviceName = extractDeviceNameFromParameters(parameters);
+
     if (deviceName.isEmpty() ||
             (deviceName.trimmed().at(0) == '/' && !QFile::exists(deviceName.trimmed()))) {
         qWarning ("QGeoSatelliteInfoSourceGypsy Empty/nonexistent GPS device name detected.");
-        qWarning ("Use gconftool-2 to set it, e.g. on terminal: ");
-        qWarning ("gconftool-2 -t string -s /apps/geoclue/master/org.freedesktop.Geoclue.GPSDevice /dev/ttyUSB0");
-        m_engine->eng_g_free(device_name);
+        qWarning("Use '%s' plugin parameter to specify device name directly", deviceNameParameter);
+        qWarning("or use '%s' plugin parameter to specify a GConf key to extract the device name.",
+                 gconfKeyParameter);
+        qWarning ("If the GConf key is used, the gconftool-2 tool can be used to set device name "
+                  "for the selected key, e.g. on terminal:");
+        qWarning ("gconftool-2 -t string -s %s /dev/ttyUSB0", gconfKeyParameter);
         return -1;
     }
     m_control = m_engine->eng_gypsy_control_get_default();
     if (!m_control) {
         qWarning("QGeoSatelliteInfoSourceGypsy unable to create Gypsy control.");
-        m_engine->eng_g_free(device_name);
         return -1;
     }
     // (path is the DBus path)
-    path = m_engine->eng_gypsy_control_create (m_control, device_name, &error);
-    m_engine->eng_g_free(device_name);
+    path = m_engine->eng_gypsy_control_create(m_control, deviceName.toLatin1().constData(), &error);
     if (!path) {
         qWarning ("QGeoSatelliteInfoSourceGypsy error creating client.");
         if (error) {
@@ -281,8 +312,13 @@ int QGeoSatelliteInfoSourceGypsy::init()
     m_engine->eng_g_free(path);
     if (!m_device || !m_satellite) {
         qWarning ("QGeoSatelliteInfoSourceGypsy error creating satellite device.");
-        qWarning ("Is GPS device set correctly? If not, use gconftool-2 to set it, e.g.: ");
-        qWarning ("gconftool-2 -t string -s /apps/geoclue/master/org.freedesktop.Geoclue.GPSDevice /dev/ttyUSB0");
+        qWarning ("Please check that the GPS device is specified correctly.");
+        qWarning("Use '%s' plugin parameter to specify device name directly", deviceNameParameter);
+        qWarning("or use '%s' plugin parameter to specify a GConf key to extract the device name.",
+                 gconfKeyParameter);
+        qWarning ("If the GConf key is used, the gconftool-2 tool can be used to set device name "
+                  "for the selected key, e.g. on terminal:");
+        qWarning ("gconftool-2 -t string -s %s /dev/ttyUSB0", gconfKeyParameter);
         if (m_device)
             g_object_unref(m_device);
         if (m_satellite)
diff --git a/src/plugins/position/gypsy/qgeosatelliteinfosource_gypsy_p.h b/src/plugins/position/gypsy/qgeosatelliteinfosource_gypsy_p.h
index f8ff9595..c9d1de71 100644
--- a/src/plugins/position/gypsy/qgeosatelliteinfosource_gypsy_p.h
+++ b/src/plugins/position/gypsy/qgeosatelliteinfosource_gypsy_p.h
@@ -103,7 +103,7 @@ class QGeoSatelliteInfoSourceGypsy : public QGeoSatelliteInfoSource
 public:
       explicit QGeoSatelliteInfoSourceGypsy(QObject *parent = 0);
       ~QGeoSatelliteInfoSourceGypsy();
-      int init();
+      int init(const QVariantMap parameters);
 
       int minimumUpdateInterval() const override;
       Error error() const override;
@@ -119,6 +119,7 @@ private slots:
 
 private:
       void setError(QGeoSatelliteInfoSource::Error error);
+      QString extractDeviceNameFromParameters(const QVariantMap &parameters) const;
 
 protected:
       // Creates an engine which encapsulates all used symbols