GIcon: add g_icon_[de]serialize()

Add support for serialising a GIcon to a GVariant and deserialising the
result back to a GIcon.

This solves a number of problems suffered by the existing to_string()
API, primarily these:

 - not forcing the icon to be a utf8 string means that we can
   efficiently encode a PNG (ie: just give the array of bytes)

 - there is no need to ensure that proper types are loaded before using
   the deserialisation interface.  'Foreign' icon types will probably
   emit a serialised format the deserialises to a GBytesIcon.

We additionally clearly document what is required for being a consumer
or implementation of #GIcon.

Further patches will be required to GdkPixbuf and GVfsIcon to bring
their implementations in line with the new rules (essentially: introduce
implementations of the new serialize() API).

https://bugzilla.gnome.org/show_bug.cgi?id=688820

1 files changed, 49 insertions, 0 deletions

diff --git a/gio/gemblemedicon.c b/gio/gemblemedicon.c
index c10dc9bc1..32e734104 100644
--- a/gio/gemblemedicon.c
+++ b/gio/gemblemedicon.c
@@ -413,6 +413,54 @@ g_emblemed_icon_from_tokens (gchar  **tokens,
   return NULL;
 }
 
+static GVariant *
+g_emblemed_icon_serialize (GIcon *icon)
+{
+  GEmblemedIcon *emblemed_icon = G_EMBLEMED_ICON (icon);
+  GVariantBuilder builder;
+  GVariant *icon_data;
+  GList *node;
+
+  icon_data = g_icon_serialize (emblemed_icon->priv->icon);
+  if (!icon_data)
+    return NULL;
+
+  g_variant_builder_init (&builder, G_VARIANT_TYPE ("(va(va{sv}))"));
+
+  g_variant_builder_add (&builder, "v", icon_data);
+  g_variant_unref (icon_data);
+
+  g_variant_builder_open (&builder, G_VARIANT_TYPE ("a(va{sv})"));
+  for (node = emblemed_icon->priv->emblems; node != NULL; node = node->next)
+    {
+      icon_data = g_icon_serialize (node->data);
+      if (icon_data)
+        {
+          /* We know how emblems serialise, so do a tweak here to
+           * reduce some of the variant wrapping and redundant storage
+           * of 'emblem' over and again...
+           */
+          if (g_variant_is_of_type (icon_data, G_VARIANT_TYPE ("(sv)")))
+            {
+              const gchar *name;
+              GVariant *content;
+
+              g_variant_get (icon_data, "(&sv)", &name, &content);
+
+              if (g_str_equal (name, "emblem") && g_variant_is_of_type (content, G_VARIANT_TYPE ("(va{sv})")))
+                g_variant_builder_add (&builder, "@(va{sv})", content);
+
+              g_variant_unref (content);
+            }
+
+          g_variant_unref (icon_data);
+        }
+    }
+  g_variant_builder_close (&builder);
+
+  return g_variant_new ("(sv)", "emblemed", g_variant_builder_end (&builder));
+}
+
 static void
 g_emblemed_icon_icon_iface_init (GIconIface *iface)
 {
@@ -420,4 +468,5 @@ g_emblemed_icon_icon_iface_init (GIconIface *iface)
   iface->equal = g_emblemed_icon_equal;
   iface->to_tokens = g_emblemed_icon_to_tokens;
   iface->from_tokens = g_emblemed_icon_from_tokens;
+  iface->serialize = g_emblemed_icon_serialize;
 }