Add JsonData, an opaque container for JSON data types

JsonData is like GValue, but it stores JSON data types (objects and
arrays) and allows us to retrieve them safely. This way we can actually
know the type of the objects returned by the parser and by the other
object walking functions.

4 files changed, 138 insertions, 16 deletions

diff --git a/json-glib/Makefile.am b/json-glib/Makefile.am
index 9af73f5..8ca1d4e 100644
--- a/json-glib/Makefile.am
+++ b/json-glib/Makefile.am
@@ -46,6 +46,7 @@ source_h_private = json-private.h
 
 source_c = \
 	json-array.c \
+	json-data.c \
 	json-object.c \
 	json-parser.c \
 	$(NULL)
diff --git a/json-glib/json-data.c b/json-glib/json-data.c
new file mode 100644
index 0000000..ce6f7ab
--- /dev/null
+++ b/json-glib/json-data.c
@@ -0,0 +1,93 @@
+#include "config.h"
+
+#include <glib.h>
+
+#include "json-types.h"
+#include "json-private.h"
+
+JsonData *
+json_data_new (JsonDataType type)
+{
+  JsonData *data;
+
+  data = g_slice_new (JsonData);
+  data->type = type;
+
+  return data;
+}
+
+void
+json_data_set_object (JsonData   *data,
+                      JsonObject *object)
+{
+  g_return_if_fail (data != NULL);
+  g_return_if_fail (JSON_DATA_TYPE (data) == JSON_DATA_OBJECT);
+  g_return_if_fail (object != NULL);
+
+  data->data.object = object;
+}
+
+/**
+ * json_data_get_object:
+ * @data: a #JsonData
+ *
+ * Retrieves the #JsonObject stored inside a #JsonData
+ *
+ * Return value: the #JsonObject
+ */
+JsonObject *
+json_data_get_object (JsonData *data)
+{
+  g_return_val_if_fail (data != NULL, NULL);
+  g_return_val_if_fail (JSON_DATA_TYPE (data) == JSON_DATA_OBJECT, NULL);
+
+  return data->data.object;
+}
+
+void
+json_data_set_array (JsonData  *data,
+                     JsonArray *array)
+{
+  g_return_if_fail (data != NULL);
+  g_return_if_fail (JSON_DATA_TYPE (data) == JSON_DATA_ARRAY);
+  g_return_if_fail (array != NULL);
+
+  data->data.array = array;
+}
+
+/**
+ * json_data_get_array:
+ * @data: a #JsonData
+ *
+ * Retrieves the #JsonArray stored inside a #JsonData
+ *
+ * Return value: the #JsonArray
+ */
+JsonArray *
+json_data_get_array (JsonData *data)
+{
+  g_return_val_if_fail (data != NULL, NULL);
+  g_return_val_if_fail (JSON_DATA_TYPE (data) == JSON_DATA_ARRAY, NULL);
+
+  return data->data.array;
+}
+
+void
+json_data_free (JsonData *data)
+{
+  if (data)
+    {
+      switch (data->type)
+        {
+        case JSON_DATA_OBJECT:
+          json_object_unref (data->data.object);
+          break;
+
+        case JSON_DATA_ARRAY:
+          json_array_unref (data->data.array);
+          break;
+        }
+
+      g_slice_free (JsonData, data);
+    }
+}
diff --git a/json-glib/json-private.h b/json-glib/json-private.h
index 962ea7b..76d27d0 100644
--- a/json-glib/json-private.h
+++ b/json-glib/json-private.h
@@ -6,6 +6,13 @@
 
 G_BEGIN_DECLS
 
+JsonData   *json_data_new              (JsonDataType  type);
+void        json_data_set_object       (JsonData     *data,
+                                        JsonObject   *object);
+void        json_data_set_array        (JsonData     *data,
+                                        JsonArray    *array);
+void        json_data_free             (JsonData     *data);
+
 JsonObject *json_object_new            (void);
 void        json_object_add_member     (JsonObject   *object,
                                         const gchar  *member_name,
diff --git a/json-glib/json-types.h b/json-glib/json-types.h
index 28e2c33..f8e61a2 100644
--- a/json-glib/json-types.h
+++ b/json-glib/json-types.h
@@ -5,27 +5,48 @@
 
 G_BEGIN_DECLS
 
+#define JSON_DATA_TYPE(data)    (((JsonData *) (data))->type)
 #define JSON_TYPE_OBJECT        (json_object_get_type ())
 #define JSON_TYPE_ARRAY         (json_array_get_type ())
 
 typedef struct _JsonObject      JsonObject;
 typedef struct _JsonArray       JsonArray;
-
-JsonObject *json_object_ref         (JsonObject  *object);
-void        json_object_unref       (JsonObject  *object);
-GList *     json_object_get_members (JsonObject  *object);
-GValue *    json_object_get_member  (JsonObject  *object,
-                                     const gchar *member_name);
-gboolean    json_object_has_member  (JsonObject  *object,
-                                     const gchar *member_name);
-guint       json_object_get_size    (JsonObject  *object);
-
-JsonArray * json_array_ref          (JsonArray   *array);
-void        json_array_unref        (JsonArray   *array);
-GList *     json_array_get_elements (JsonArray   *array);
-GValue *    json_array_get_element  (JsonArray   *array,
-                                     guint        index_);
-guint       json_array_get_length   (JsonArray   *array);
+typedef struct _JsonData        JsonData;
+
+typedef enum {
+  JSON_DATA_OBJECT,
+  JSON_DATA_ARRAY
+} JsonDataType;
+
+struct _JsonData
+{
+  /*< private >*/
+  JsonDataType type;
+
+  union {
+    JsonObject *object;
+    JsonArray *array;
+  } data;
+};
+
+JsonObject * json_data_get_object    (JsonData    *data);
+JsonArray *  json_data_get_array     (JsonData    *data);
+
+JsonObject * json_object_ref         (JsonObject  *object);
+void         json_object_unref       (JsonObject  *object);
+GList *      json_object_get_members (JsonObject  *object);
+GValue *     json_object_get_member  (JsonObject  *object,
+                                      const gchar *member_name);
+gboolean     json_object_has_member  (JsonObject  *object,
+                                      const gchar *member_name);
+guint        json_object_get_size    (JsonObject  *object);
+
+JsonArray *  json_array_ref          (JsonArray   *array);
+void         json_array_unref        (JsonArray   *array);
+GList *      json_array_get_elements (JsonArray   *array);
+GValue *     json_array_get_element  (JsonArray   *array,
+                                      guint        index_);
+guint        json_array_get_length   (JsonArray   *array);
 
 G_END_DECLS