Refactor toJson/fillJson

Both now use through a common JsonConverter<> template class with its
base definition tuned for structs/QJsonObjects and specialisations for
non-object types. This new implementation doesn't work with virtual
fillJson functions yet (so EventContent classes still use toJson as a
member function) and does not cope quite well with non-constructible
objects (you have to specialise JsonConverter<> rather than, more
intuitively, JsonObjectConverter<>), but overall is more streamlined
compared to the previous implementation. It also fixes one important
issue that pushed for a rewrite: the previous implementation was not
working with structure hierarchies at all so (in particular) the Filter
part of CS API was totally disfunctional.

1 files changed, 18 insertions, 17 deletions

diff --git a/lib/events/accountdataevents.h b/lib/events/accountdataevents.h
index d1c1abc8..a99d85ac 100644
--- a/lib/events/accountdataevents.h
+++ b/lib/events/accountdataevents.h
@@ -36,37 +36,38 @@ namespace QMatrixClient
         order_type order;
 
         TagRecord (order_type order = none) : order(order) { }
-        explicit TagRecord(const QJsonObject& jo)
+
+        bool operator<(const TagRecord& other) const
+        {
+            // Per The Spec, rooms with no order should be after those with order
+            return !order.omitted() &&
+                        (other.order.omitted() || order.value() < other.order.value());
+        }
+    };
+
+    template <> struct JsonObjectConverter<TagRecord>
+    {
+        static void fillFrom(const QJsonObject& jo, TagRecord& rec)
         {
             // Parse a float both from JSON double and JSON string because
             // libqmatrixclient previously used to use strings to store order.
             const auto orderJv = jo.value("order"_ls);
             if (orderJv.isDouble())
-                order = fromJson<float>(orderJv);
-            else if (orderJv.isString())
+                rec.order = fromJson<float>(orderJv);
+            if (orderJv.isString())
             {
                 bool ok;
-                order = orderJv.toString().toFloat(&ok);
+                rec.order = orderJv.toString().toFloat(&ok);
                 if (!ok)
-                    order = none;
+                    rec.order = none;
             }
         }
-
-        bool operator<(const TagRecord& other) const
+        static void dumpTo(QJsonObject& jo, const TagRecord& rec)
         {
-            // Per The Spec, rooms with no order should be after those with order
-            return !order.omitted() &&
-                        (other.order.omitted() || order.value() < other.order.value());
+            addParam<IfNotEmpty>(jo, QStringLiteral("order"), rec.order);
         }
     };
 
-    inline QJsonValue toJson(const TagRecord& rec)
-    {
-        QJsonObject o;
-        addParam<IfNotEmpty>(o, QStringLiteral("order"), rec.order);
-        return o;
-    }
-
     using TagsMap = QHash<QString, TagRecord>;
 
 #define DEFINE_SIMPLE_EVENT(_Name, _TypeId, _ContentType, _ContentKey) \