[libgdata] app: Add support for JSON to GDataAPPCategories

[Philip Withnall <pwithnall src gnome org>]

commit f89b123bf15dc1f4eee107b6a65a2a6bd1273253
Author: Philip Withnall <philip tecnocode co uk>
Date:   Sun Apr 19 18:02:03 2015 +0100

    app: Add support for JSON to GDataAPPCategories
    
    This allows downloading the YouTube category list with v3 of the YouTube
    API.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=687597

 gdata/app/gdata-app-categories.c |   76 ++++++++++++++++++++++++++++++++++++++
 1 files changed, 76 insertions(+), 0 deletions(-)
---
diff --git a/gdata/app/gdata-app-categories.c b/gdata/app/gdata-app-categories.c
index 375a1e2..aaf7bfa 100644
--- a/gdata/app/gdata-app-categories.c
+++ b/gdata/app/gdata-app-categories.c
@@ -44,6 +44,11 @@ static void gdata_app_categories_get_property (GObject *object, guint property_i
 static gboolean pre_parse_xml (GDataParsable *parsable, xmlDoc *doc, xmlNode *root_node, gpointer user_data, 
GError **error);
 static gboolean parse_xml (GDataParsable *parsable, xmlDoc *doc, xmlNode *node, gpointer user_data, GError 
**error);
 static gboolean post_parse_xml (GDataParsable *parsable, gpointer user_data, GError **error);
+static gboolean
+parse_json (GDataParsable *parsable, JsonReader *reader, gpointer user_data,
+            GError **error);
+static gboolean
+post_parse_json (GDataParsable *parsable, gpointer user_data, GError **error);
 
 struct _GDataAPPCategoriesPrivate {
        GList *categories;
@@ -72,6 +77,10 @@ gdata_app_categories_class_init (GDataAPPCategoriesClass *klass)
        parsable_class->pre_parse_xml = pre_parse_xml;
        parsable_class->parse_xml = parse_xml;
        parsable_class->post_parse_xml = post_parse_xml;
+
+       parsable_class->parse_json = parse_json;
+       parsable_class->post_parse_json = post_parse_json;
+
        parsable_class->element_name = "categories";
        parsable_class->element_namespace = "app";
 
@@ -195,6 +204,73 @@ post_parse_xml (GDataParsable *parsable, gpointer user_data, GError **error)
        return TRUE;
 }
 
+/* Reference: https://developers.google.com/youtube/v3/docs/videoCategories/list */
+static gboolean
+parse_json (GDataParsable *parsable, JsonReader *reader, gpointer user_data, GError **error)
+{
+       GDataAPPCategories *self = GDATA_APP_CATEGORIES (parsable);
+       GDataAPPCategoriesPrivate *priv = self->priv;
+
+       if (g_strcmp0 (json_reader_get_member_name (reader), "items") == 0) {
+               guint i, elements;
+
+               /* Loop through the elements array. */
+               for (i = 0, elements = (guint) json_reader_count_elements (reader); i < elements; i++) {
+                       GDataCategory *category = NULL;
+                       const gchar *id, *title;
+                       const GError *child_error = NULL;
+
+                       json_reader_read_element (reader, i);
+
+                       json_reader_read_member (reader, "id");
+                       id = json_reader_get_string_value (reader);
+                       json_reader_end_member (reader);
+
+                       json_reader_read_member (reader, "snippet");
+
+                       json_reader_read_member (reader, "title");
+                       title = json_reader_get_string_value (reader);
+                       json_reader_end_member (reader);
+
+                       child_error = json_reader_get_error (reader);
+
+                       if (child_error != NULL) {
+                               return gdata_parser_error_from_json_error (reader,
+                                                                          child_error,
+                                                                          error);
+                       }
+
+                       /* Create the category. */
+                       category = gdata_category_new (id, NULL, title);
+                       priv->categories = g_list_prepend (priv->categories,
+                                                          category);
+
+                       json_reader_end_member (reader);  /* snippet */
+                       json_reader_end_element (reader);  /* category */
+               }
+
+               return TRUE;
+       } else if (g_strcmp0 (json_reader_get_member_name (reader), "kind") == 0 ||
+                  g_strcmp0 (json_reader_get_member_name (reader), "etag") == 0 ||
+                  g_strcmp0 (json_reader_get_member_name (reader), "id") == 0) {
+               /* Ignore. */
+               return TRUE;
+       } else {
+               return GDATA_PARSABLE_CLASS (gdata_app_categories_parent_class)->parse_json (parsable, 
reader, user_data, error);
+       }
+}
+
+static gboolean
+post_parse_json (GDataParsable *parsable, gpointer user_data, GError **error)
+{
+       GDataAPPCategoriesPrivate *priv = GDATA_APP_CATEGORIES (parsable)->priv;
+
+       /* Reverse our lists of stuff. */
+       priv->categories = g_list_reverse (priv->categories);
+
+       return TRUE;
+}
+
 /**
  * gdata_app_categories_get_categories:
  * @self: a #GDataAPPCategories