[empathy] Fix reduced accuracy concerns

[Pierre-Luc Beaudoin <plbeaudoin src gnome org>]

commit 713fb600634add0e0abe35489402e5ed8d5fde10
Author: Pierre-Luc Beaudoin <pierre-luc beaudoin collabora co uk>
Date:   Thu Jul 2 14:25:48 2009 -0400

    Fix reduced accuracy concerns
    
    As pointed out by users, the previous reduced accuracy mode
    was not the best.  It is better to trunkate the coordinates
    rather than adding a random value to it.
    
    This patch also replaces strcmp by tp_strdiff

 libempathy-gtk/empathy-location-manager.c |   36 ++++++++++++++--------------
 src/empathy-preferences.ui                |    2 +-
 2 files changed, 19 insertions(+), 19 deletions(-)
---
diff --git a/libempathy-gtk/empathy-location-manager.c b/libempathy-gtk/empathy-location-manager.c
index 278af72..087ce56 100644
--- a/libempathy-gtk/empathy-location-manager.c
+++ b/libempathy-gtk/empathy-location-manager.c
@@ -21,6 +21,10 @@
 
 #include "config.h"
 
+/* Needed for trunc */
+#define _ISOC9X_SOURCE 1
+#define _ISOC99_SOURCE 1
+#include <math.h>
 #include <string.h>
 #include <time.h>
 
@@ -63,7 +67,6 @@ typedef struct {
     GeoclueAddress *gc_address;
 
     gboolean reduce_accuracy;
-    gdouble reduce_value;
     EmpathyAccountManager *account_manager;
 
     /* The idle id for publish_on_idle func */
@@ -312,7 +315,8 @@ address_changed_cb (GeoclueAddress *address,
     {
       GValue *new_value;
       /* Discard street information if reduced accuracy is on */
-      if (priv->reduce_accuracy && strcmp (key, EMPATHY_LOCATION_STREET) == 0)
+      if (priv->reduce_accuracy &&
+          !tp_strdiff (key, EMPATHY_LOCATION_STREET))
         continue;
 
       new_value = tp_g_value_slice_new_string (value);
@@ -368,7 +372,11 @@ position_changed_cb (GeocluePosition *position,
 
   if (fields & GEOCLUE_POSITION_FIELDS_LONGITUDE)
     {
-      longitude += priv->reduce_value;
+
+      if (priv->reduce_accuracy)
+        /* Truncate at 1 decimal place */
+        longitude = trunc (longitude * 10.0) / 10.0;
+
       new_value = tp_g_value_slice_new_double (longitude);
       g_hash_table_insert (priv->location, g_strdup (EMPATHY_LOCATION_LON),
           new_value);
@@ -381,7 +389,10 @@ position_changed_cb (GeocluePosition *position,
 
   if (fields & GEOCLUE_POSITION_FIELDS_LATITUDE)
     {
-      latitude += priv->reduce_value;
+      if (priv->reduce_accuracy)
+        /* Truncate at 1 decimal place */
+        latitude = trunc (latitude * 10.0) / 10.0;
+
       new_value = tp_g_value_slice_new_double (latitude);
       g_hash_table_replace (priv->location, g_strdup (EMPATHY_LOCATION_LAT),
           new_value);
@@ -577,11 +588,11 @@ resource_cb (EmpathyConf  *conf,
   if (!empathy_conf_get_bool (conf, key, &resource_enabled))
     return;
 
-  if (strcmp (key, EMPATHY_PREFS_LOCATION_RESOURCE_NETWORK) == 0)
+  if (tp_strdiff (key, EMPATHY_PREFS_LOCATION_RESOURCE_NETWORK) == FALSE)
     resource = GEOCLUE_RESOURCE_NETWORK;
-  if (strcmp (key, EMPATHY_PREFS_LOCATION_RESOURCE_CELL) == 0)
+  if (tp_strdiff (key, EMPATHY_PREFS_LOCATION_RESOURCE_CELL) == FALSE)
     resource = GEOCLUE_RESOURCE_CELL;
-  if (strcmp (key, EMPATHY_PREFS_LOCATION_RESOURCE_GPS) == 0)
+  if (tp_strdiff (key, EMPATHY_PREFS_LOCATION_RESOURCE_GPS) == FALSE)
     resource = GEOCLUE_RESOURCE_GPS;
 
   if (resource_enabled)
@@ -609,17 +620,6 @@ accuracy_cb (EmpathyConf  *conf,
     return;
   priv->reduce_accuracy = enabled;
 
-  if (enabled)
-    {
-      GRand *rand = g_rand_new_with_seed (time (NULL));
-      priv->reduce_value = g_rand_double_range (rand, -0.25, 0.25);
-      g_rand_free (rand);
-    }
-  else
-    {
-      priv->reduce_value = 0.0;
-    }
-
   if (!priv->geoclue_is_setup)
     return;
 
diff --git a/src/empathy-preferences.ui b/src/empathy-preferences.ui
index a383607..1e3a425 100644
--- a/src/empathy-preferences.ui
+++ b/src/empathy-preferences.ui
@@ -434,7 +434,7 @@
                                     <property name="visible">True</property>
                                     <property name="xalign">0</property>
                                     <property name="wrap">True</property>
-                                    <property name="label" translatable="yes">Reduced location accuracy means that nothing more precise than your city, state and country will be published.  GPS coordinates will have a random value added (&#xB1;0.25&#xB0;).</property>
+                                    <property name="label" translatable="yes">Reduced location accuracy means that nothing more precise than your city, state and country will be published.  GPS coordinates will be accurate to 1 decimal place.</property>
                                     <attributes>
                                       <attribute name="scale" value="0.8"/>
                                     </attributes>