Add a GPS modem geolocation source

1 files changed, 250 insertions, 0 deletions

diff --git a/src/gclue-modem-gps.c b/src/gclue-modem-gps.c
new file mode 100644
index 0000000..e3cec30
--- /dev/null
+++ b/src/gclue-modem-gps.c
@@ -0,0 +1,250 @@
+/* vim: set et ts=8 sw=8: */
+/*
+ * Copyright (C) 2014 Red Hat, Inc.
+ *
+ * Geoclue is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * Geoclue is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with Geoclue; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Authors: Zeeshan Ali (Khattak) <zeeshanak@gnome.org>
+ */
+
+#include <stdlib.h>
+#include <glib.h>
+#include <string.h>
+#include "gclue-modem-gps.h"
+#include "geocode-glib/geocode-location.h"
+
+/**
+ * SECTION:gclue-modem-gps
+ * @short_description: WiFi-based geolocation
+ * @include: gclue-glib/gclue-modem-gps.h
+ *
+ * Contains functions to get the geolocation from a GPS modem.
+ **/
+
+struct _GClueModemGPSPrivate {
+        MMLocationGpsRaw *gps_raw;
+
+        GCancellable *cancellable;
+};
+
+static MMModemLocationSource
+gclue_modem_gps_get_req_modem_location_caps (GClueModemSource *source,
+                                             const char      **caps_name);
+static void
+gclue_modem_gps_modem_location_changed (GClueModemSource *source,
+                                        MMModemLocation  *modem_location);
+
+G_DEFINE_TYPE (GClueModemGPS, gclue_modem_gps, GCLUE_TYPE_MODEM_SOURCE)
+
+static void
+gclue_modem_gps_finalize (GObject *ggps)
+{
+        GClueModemGPSPrivate *priv = GCLUE_MODEM_GPS (ggps)->priv;
+
+        g_cancellable_cancel (priv->cancellable);
+        g_clear_object (&priv->cancellable);
+        g_clear_object (&priv->gps_raw);
+
+        G_OBJECT_CLASS (gclue_modem_gps_parent_class)->finalize (ggps);
+}
+
+static void
+gclue_modem_gps_class_init (GClueModemGPSClass *klass)
+{
+        GClueModemSourceClass *source_class = GCLUE_MODEM_SOURCE_CLASS (klass);
+        GObjectClass *ggps_class = G_OBJECT_CLASS (klass);
+
+        source_class->get_req_modem_location_caps =
+                gclue_modem_gps_get_req_modem_location_caps;
+        source_class->modem_location_changed =
+                gclue_modem_gps_modem_location_changed;
+        ggps_class->finalize = gclue_modem_gps_finalize;
+
+        g_type_class_add_private (klass, sizeof (GClueModemGPSPrivate));
+}
+
+static void
+gclue_modem_gps_init (GClueModemGPS *source)
+{
+        source->priv = G_TYPE_INSTANCE_GET_PRIVATE ((source), GCLUE_TYPE_MODEM_GPS, GClueModemGPSPrivate);
+
+        source->priv->cancellable = g_cancellable_new ();
+}
+
+static void
+on_modem_gps_destroyed (gpointer data,
+                 GObject *where_the_object_was)
+{
+        GClueModemGPS **source = (GClueModemGPS **) data;
+
+        *source = NULL;
+}
+
+/**
+ * gclue_modem_gps_get_singleton:
+ *
+ * Get the #GClueModemGPS singleton.
+ *
+ * Returns: (transfer full): a new ref to #GClueModemGPS. Use g_object_unref()
+ * when done.
+ **/
+GClueModemGPS *
+gclue_modem_gps_get_singleton (void)
+{
+        static GClueModemGPS *source = NULL;
+
+        if (source == NULL) {
+                source = g_object_new (GCLUE_TYPE_MODEM_GPS, NULL);
+                g_object_weak_ref (G_OBJECT (source),
+                                   on_modem_gps_destroyed,
+                                   &source);
+        } else
+                g_object_ref (source);
+
+        return source;
+}
+
+static gdouble
+get_accuracy_from_nmea (GClueModemGPS     *source,
+                        MMLocationGpsNmea *location_nmea)
+{
+        const char *gga;
+        gdouble hdop; /* Horizontal Dilution Of Precision */
+        char **parts;
+
+        gga = mm_location_gps_nmea_get_trace (location_nmea, "$GPGGA");
+        if (gga == NULL) {
+                g_warning ("Failed to find GGA sentence:\n");
+                return 300;
+        }
+
+        parts = g_strsplit (gga, ",", -1);
+        if (g_strv_length (parts) < 14 ) {
+                g_warning ("Failed to parse NMEA GGA sentence:\n%s", gga);
+                g_strfreev (parts);
+                return 300;
+        }
+
+        hdop = g_ascii_strtod (parts[8], NULL);
+        g_strfreev (parts);
+
+        /* FIXME: These are really just rough estimates based on:
+         *        http://en.wikipedia.org/wiki/Dilution_of_precision_%28GPS%29#Meaning_of_DOP_Values
+         */
+        if (hdop <= 1)
+                return 0;
+        else if (hdop <= 2)
+                return 1;
+        else if (hdop <= 5)
+                return 3;
+        else if (hdop <= 10)
+                return 50;
+        else if (hdop <= 20)
+                return 100;
+        else
+                return 300;
+}
+
+static void
+on_get_gps_nmea_ready (GObject      *source_object,
+                       GAsyncResult *res,
+                       gpointer      user_data)
+{
+        GClueModemGPS *source = GCLUE_MODEM_GPS (user_data);
+        GClueModemGPSPrivate *priv = source->priv;
+        MMModemLocation *modem_location = MM_MODEM_LOCATION (source_object);
+        MMLocationGpsNmea *location_nmea;
+        GeocodeLocation *location;
+        gdouble latitude, longitude, accuracy;
+        GError *error = NULL;
+
+        location_nmea = mm_modem_location_get_gps_nmea_finish (modem_location,
+                                                               res,
+                                                               &error);
+        if (error != NULL) {
+                g_warning ("Failed to get location from NMEA information: %s",
+                           error->message);
+                g_error_free (error);
+                return;
+        }
+
+        if (location_nmea == NULL) {
+                g_debug ("No NMEA");
+                return;
+        }
+
+        latitude = mm_location_gps_raw_get_latitude (priv->gps_raw);
+        longitude = mm_location_gps_raw_get_longitude (priv->gps_raw);
+        g_clear_object (&priv->gps_raw);
+
+        accuracy = get_accuracy_from_nmea (source, location_nmea);
+        g_object_unref (location_nmea);
+
+        location = geocode_location_new (latitude, longitude, accuracy);
+        gclue_location_source_set_location (GCLUE_LOCATION_SOURCE (source),
+                                            location);
+}
+
+static void
+on_get_gps_raw_ready (GObject      *source_object,
+                      GAsyncResult *res,
+                      gpointer      user_data)
+{
+        GClueModemGPS *source = GCLUE_MODEM_GPS (user_data);
+        GClueModemGPSPrivate *priv = source->priv;
+        MMModemLocation *modem_location = MM_MODEM_LOCATION (source_object);
+        GError *error = NULL;
+
+        priv->gps_raw = mm_modem_location_get_gps_raw_finish (modem_location,
+                                                              res,
+                                                              &error);
+        if (error != NULL) {
+                g_warning ("Failed to get location from 3GPP: %s",
+                           error->message);
+                g_error_free (error);
+                return;
+        }
+
+        if (priv->gps_raw == NULL) {
+                g_debug ("No GPS");
+                return;
+        }
+
+        mm_modem_location_get_gps_nmea (modem_location,
+                                        source->priv->cancellable,
+                                        on_get_gps_nmea_ready,
+                                        source);
+}
+
+static void
+gclue_modem_gps_modem_location_changed (GClueModemSource *source,
+                                        MMModemLocation  *modem_location)
+{
+        mm_modem_location_get_gps_raw (modem_location,
+                                       GCLUE_MODEM_GPS (source)->priv->cancellable,
+                                       on_get_gps_raw_ready,
+                                       source);
+}
+
+static MMModemLocationSource
+gclue_modem_gps_get_req_modem_location_caps (GClueModemSource *source,
+                                             const char      **caps_name)
+{
+        if (caps_name != NULL)
+                *caps_name = "GPS";
+
+        return MM_MODEM_LOCATION_SOURCE_GPS_RAW |
+               MM_MODEM_LOCATION_SOURCE_GPS_NMEA;
+}