[libgweather] GWeatherInfo: improve performance with a better use of libsoup

[Giovanni Campagna <gcampagna src gnome org>]

commit 3ebea5790be0b70e91959c0381941664d2f9a6ea
Author: Giovanni Campagna <gcampagna src gnome org>
Date:   Wed Mar 6 15:58:09 2013 +0100

    GWeatherInfo: improve performance with a better use of libsoup
    
    Use a shared session instead of one for each GWeatherInfo. This
    way we can share the connections.
    Also, enable caching and gzip encoding.
    
    This should reduce our perfomance impact on upstream services.
    Caching is actually required by the terms and conditions of yr.no
    and Yahoo weather.

 libgweather/weather.c |   59 +++++++++++++++++++++++++++++++++++++++++++++---
 1 files changed, 55 insertions(+), 4 deletions(-)
---
diff --git a/libgweather/weather.c b/libgweather/weather.c
index c3d4792..e63fda8 100644
--- a/libgweather/weather.c
+++ b/libgweather/weather.c
@@ -420,6 +420,59 @@ gweather_info_init (GWeatherInfo *info)
     gweather_info_reset (info);
 }
 
+static SoupCache *
+get_cache (void)
+{
+    SoupCache *cache;
+    char *filename;
+
+    filename = g_build_filename (g_get_user_cache_dir (),
+                                "libgweather", NULL);
+
+    if (g_mkdir_with_parents (filename, 0700) < 0) {
+       g_free (filename);
+       return NULL;
+    }
+
+    cache = soup_cache_new (filename, SOUP_CACHE_SINGLE_USER);
+
+    g_free (filename);
+    return cache;
+}
+
+static void
+dump_and_unref_cache (SoupCache *cache)
+{
+    soup_cache_dump (cache);
+    g_object_unref (cache);
+}
+
+static SoupSession *
+ref_session (void)
+{
+    static SoupSession *session;
+    SoupCache *cache;
+
+    if (session != NULL)
+       return g_object_ref (session);
+
+    session = soup_session_async_new ();
+    soup_session_add_feature_by_type (session, SOUP_TYPE_PROXY_RESOLVER_DEFAULT);
+    soup_session_add_feature_by_type (session, SOUP_TYPE_CONTENT_DECODER);
+
+    cache = get_cache ();
+    soup_session_add_feature (session, SOUP_SESSION_FEATURE (cache));
+    g_object_set_data_full (G_OBJECT (session), "libgweather-cache", g_object_ref (cache),
+                           (GDestroyNotify) dump_and_unref_cache);
+
+    soup_cache_load (cache);
+    g_object_unref (cache);
+
+    g_object_add_weak_pointer (G_OBJECT (session), (void**) &session);
+
+    return session;
+}
+
 void
 gweather_info_update (GWeatherInfo *info)
 {
@@ -432,10 +485,8 @@ gweather_info_update (GWeatherInfo *info)
 
     gweather_info_reset (info);
 
-    if (!priv->session) {
-       priv->session = soup_session_async_new ();
-       soup_session_add_feature_by_type (priv->session, SOUP_TYPE_PROXY_RESOLVER_DEFAULT);
-    }
+    if (!priv->session)
+       priv->session = ref_session ();
 
     if (priv->providers & GWEATHER_PROVIDER_METAR)
        metar_start_open (info);