From 491e392af73be3ebfd928e80efc0514fd43b8e87 Mon Sep 17 00:00:00 2001
From: Kitsune Ral <Kitsune-Ral@users.sf.net>
Date: Thu, 16 Nov 2017 14:10:08 +0900
Subject: Simplify code that loads events from JSON arrays

---
 events/event.h           | 41 +++++++++++++++++++++++------------------
 jobs/roommessagesjob.cpp |  4 ++--
 jobs/syncjob.h           |  5 ++---
 3 files changed, 27 insertions(+), 23 deletions(-)

diff --git a/events/event.h b/events/event.h
index c0c1b603..cc99b57b 100644
--- a/events/event.h
+++ b/events/event.h
@@ -63,6 +63,10 @@ namespace QMatrixClient
             // (and in most cases it will be a combination of other fields
             // instead of "content" field).
 
+            /** Create an event with proper type from a JSON object
+             * Use this factory to detect the type from the JSON object contents
+             * and create an event object of that type.
+             */
             static Event* fromJson(const QJsonObject& obj);
 
         protected:
@@ -77,26 +81,27 @@ namespace QMatrixClient
             Q_PROPERTY(QJsonObject contentJson READ contentJson CONSTANT)
     };
     using EventType = Event::Type;
-    template <typename EventT>
-    using EventsBatch = std::vector<EventT*>;
-    using Events = EventsBatch<Event>;
 
-    template <typename BaseEventT = Event,
-              typename BatchT = EventsBatch<BaseEventT> >
-    inline BatchT makeEvents(const QJsonArray& objs)
+    template <typename EventT>
+    class EventsBatch : public std::vector<EventT*>
     {
-        BatchT evs;
-        // The below line accommodates the difference in size types of
-        // STL and Qt containers.
-        evs.reserve(static_cast<typename BatchT::size_type>(objs.size()));
-        for (auto objValue: objs)
-        {
-            const auto o = objValue.toObject();
-            auto e = BaseEventT::fromJson(o);
-            evs.push_back(e ? e : new BaseEventT(EventType::Unknown, o));
-        }
-        return evs;
-    }
+        public:
+            void fromJson(const QJsonObject& container, const QString& node)
+            {
+                const auto objs = container.value(node).toArray();
+                using size_type = typename std::vector<EventT*>::size_type;
+                // The below line accommodates the difference in size types of
+                // STL and Qt containers.
+                this->reserve(static_cast<size_type>(objs.size()));
+                for (auto objValue: objs)
+                {
+                    const auto o = objValue.toObject();
+                    auto e = EventT::fromJson(o);
+                    this->push_back(e ? e : new EventT(EventType::Unknown, o));
+                }
+            }
+    };
+    using Events = EventsBatch<Event>;
 
     /** This class corresponds to m.room.* events */
     class RoomEvent : public Event
diff --git a/jobs/roommessagesjob.cpp b/jobs/roommessagesjob.cpp
index 078c692a..c527cc71 100644
--- a/jobs/roommessagesjob.cpp
+++ b/jobs/roommessagesjob.cpp
@@ -58,8 +58,8 @@ QString RoomMessagesJob::end() const
 
 BaseJob::Status RoomMessagesJob::parseJson(const QJsonDocument& data)
 {
-    QJsonObject obj = data.object();
-    d->events.assign(makeEvents<RoomEvent>(obj.value("chunk").toArray()));
+    const auto obj = data.object();
+    d->events.fromJson(obj, "chunk");
     d->end = obj.value("end").toString();
     return Success;
 }
diff --git a/jobs/syncjob.h b/jobs/syncjob.h
index b1db914d..08bd773e 100644
--- a/jobs/syncjob.h
+++ b/jobs/syncjob.h
@@ -36,11 +36,10 @@ namespace QMatrixClient
                     explicit Batch(QString k) : jsonKey(std::move(k)) { }
                     void fromJson(const QJsonObject& roomContents)
                     {
-                        this->assign(makeEvents<EventT>(
-                            roomContents[jsonKey].toObject()["events"].toArray()));
+                        EventsBatch<EventT>::fromJson(
+                                    roomContents[jsonKey].toObject(), "events");
                     }
 
-
                 private:
                     QString jsonKey;
             };
-- 
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