GetRoomEventsJob (replaces RoomMessagesJob) + refactoring

1. Updates in this commit (see further) allow to generate and build
GetRoomEventsJob from message_pagination.yaml; this job completely
preempts RoomMessagesJob.
2. EventsBatch<> is no more a thing; there's EventsArray<> to replace it
but it's loaded from a JSON array rather than an event batch (a JSON
array inside another JSON object). SyncJob that used it extensively has
been moved to "conventional" containers (Events, RoomEvents and the
newly introduced StateEvents). RoomMessagesJob that also used
EventsBatch<> is decommissioned (see above).
3. RoomEventsRange is now an alias for Range<RoomEvents>, defined in
util.h (otherwise almost the same).
4. Connection::getMessages() is no more. Use Room::getPreviousContent()
and Connection::callApi<GetRooMEventsJob>() instead.
5. Moving things around in Room, since SyncJob now supplies state events
in more specific StateEvents, rather than RoomEvents.

15 files changed, 330 insertions, 355 deletions

diff --git a/lib/connection.cpp b/lib/connection.cpp
index adeb7929..b433ccbc 100644
--- a/lib/connection.cpp
+++ b/lib/connection.cpp
@@ -30,7 +30,6 @@
 #include "jobs/generated/account-data.h"
 #include "jobs/sendeventjob.h"
 #include "jobs/joinroomjob.h"
-#include "jobs/roommessagesjob.h"
 #include "jobs/syncjob.h"
 #include "jobs/mediathumbnailjob.h"
 #include "jobs/downloadfilejob.h"
@@ -372,11 +371,6 @@ void Connection::leaveRoom(Room* room)
     callApi<LeaveRoomJob>(room->id());
 }
 
-RoomMessagesJob* Connection::getMessages(Room* room, const QString& from) const
-{
-    return callApi<RoomMessagesJob>(room->id(), from);
-}
-
 inline auto splitMediaId(const QString& mediaId)
 {
     auto idParts = mediaId.split('/');
diff --git a/lib/connection.h b/lib/connection.h
index 839371ef..22f71eac 100644
--- a/lib/connection.h
+++ b/lib/connection.h
@@ -331,9 +331,7 @@ namespace QMatrixClient
                                                 RoomEvent* event) const;
             /** @deprecated Use callApi<LeaveRoomJob>() or Room::leaveRoom() instead */
             virtual void leaveRoom( Room* room );
-            /** @deprecated User callApi<RoomMessagesJob>() or Room::getPreviousContent() instead */
-            virtual RoomMessagesJob* getMessages(Room* room,
-                                                 const QString& from) const;
+
         signals:
             /**
              * @deprecated
diff --git a/lib/events/event.cpp b/lib/events/event.cpp
index 193250de..57049671 100644
--- a/lib/events/event.cpp
+++ b/lib/events/event.cpp
@@ -160,14 +160,13 @@ void RoomEvent::addId(const QString& id)
 template <>
 RoomEventPtr _impl::doMakeEvent(const QJsonObject& obj)
 {
-    return RoomEventPtr { makeIfMatches<RoomEvent,
-        RoomMessageEvent, RoomNameEvent, RoomAliasesEvent,
-        RoomCanonicalAliasEvent, RoomMemberEvent, RoomTopicEvent,
-        RoomAvatarEvent, EncryptionEvent, RedactionEvent>
-            (obj, obj["type"].toString()) };
-}
+    // Check more specific event types first
+    if (auto e = doMakeEvent<StateEventBase>(obj))
+        return e;
 
-StateEventBase::~StateEventBase() = default;
+    return makeIfMatches<RoomEvent,
+        RoomMessageEvent, RedactionEvent>(obj, obj["type"].toString());
+}
 
 bool StateEventBase::repeatsState() const
 {
@@ -176,3 +175,13 @@ bool StateEventBase::repeatsState() const
                                 .toObject().value("prev_content");
     return contentJson == prevContentJson;
 }
+
+template<>
+StateEventPtr _impl::doMakeEvent<StateEventBase>(const QJsonObject& obj)
+{
+    return makeIfMatches<StateEventBase,
+        RoomNameEvent, RoomAliasesEvent,
+        RoomCanonicalAliasEvent, RoomMemberEvent, RoomTopicEvent,
+        RoomAvatarEvent, EncryptionEvent>(obj, obj["type"].toString());
+
+}
diff --git a/lib/events/event.h b/lib/events/event.h
index 396406f1..8449c2ec 100644
--- a/lib/events/event.h
+++ b/lib/events/event.h
@@ -53,7 +53,10 @@ namespace QMatrixClient
         }
 
         template <typename EventT>
-        event_ptr_tt<EventT> doMakeEvent(const QJsonObject& obj);
+        inline event_ptr_tt<EventT> doMakeEvent(const QJsonObject& obj)
+        {
+            return create<EventT>(obj);
+        }
     }
 
     class Event
@@ -114,7 +117,7 @@ namespace QMatrixClient
      * parameter type) and create an event object of that type.
      */
     template <typename EventT>
-    event_ptr_tt<EventT> makeEvent(const QJsonObject& obj)
+    inline event_ptr_tt<EventT> makeEvent(const QJsonObject& obj)
     {
         auto e = _impl::doMakeEvent<EventT>(obj);
         if (!e)
@@ -128,50 +131,17 @@ namespace QMatrixClient
         EventPtr doMakeEvent<Event>(const QJsonObject& obj);
     }
 
-    template <> struct FromJson<EventPtr>
+    template <typename EventT> struct FromJson<event_ptr_tt<EventT>>
     {
-        EventPtr operator()(const QJsonValue& jv) const
+        auto operator()(const QJsonValue& jv) const
         {
-            return makeEvent<Event>(jv.toObject());
+            return makeEvent<EventT>(jv.toObject());
         }
     };
 
-    /**
-     * \brief A vector of pointers to events with deserialisation capabilities
-     *
-     * This is a simple wrapper over a generic vector type that adds
-     * a convenience method to deserialise events from QJsonArray.
-     * \tparam EventT base type of all events in the vector
-     */
     template <typename EventT>
-    class EventsBatch : public std::vector<event_ptr_tt<EventT>>
-    {
-        public:
-            /**
-             * \brief Deserialise events from an array
-             *
-             * Given the following JSON construct, creates events from
-             * the array stored at key "node":
-             * \code
-             * "container": {
-             *     "node": [ { "event_id": "!evt1:srv.org", ... }, ... ]
-             * }
-             * \endcode
-             * \param container - the wrapping JSON object
-             * \param node - the key in container that holds the array of events
-             */
-            void fromJson(const QJsonObject& container, const QString& node)
-            {
-                const auto objs = container.value(node).toArray();
-                using size_type = typename std::vector<event_ptr_tt<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 (const auto& objValue: objs)
-                    this->emplace_back(makeEvent<EventT>(objValue.toObject()));
-            }
-    };
-    using Events = EventsBatch<Event>;
+    using EventsArray = std::vector<event_ptr_tt<EventT>>;
+    using Events = EventsArray<Event>;
 
     class RedactionEvent;
 
@@ -231,8 +201,9 @@ namespace QMatrixClient
             event_ptr_tt<RedactionEvent> _redactedBecause;
             QString _txnId;
     };
-    using RoomEvents = EventsBatch<RoomEvent>;
     using RoomEventPtr = event_ptr_tt<RoomEvent>;
+    using RoomEvents = EventsArray<RoomEvent>;
+    using RoomEventsRange = Range<RoomEvents>;
 
     namespace _impl
     {
@@ -240,29 +211,6 @@ namespace QMatrixClient
         RoomEventPtr doMakeEvent<RoomEvent>(const QJsonObject& obj);
     }
 
-    /**
-     * Conceptually similar to QStringView (but much more primitive), it's a
-     * simple abstraction over a pair of RoomEvents::const_iterator values
-     * referring to the beginning and the end of a range in a RoomEvents
-     * container.
-     */
-    struct RoomEventsRange
-    {
-        RoomEvents::iterator from;
-        RoomEvents::iterator to;
-
-        RoomEvents::size_type size() const
-        {
-            Q_ASSERT(std::distance(from, to) >= 0);
-            return RoomEvents::size_type(std::distance(from, to));
-        }
-        bool empty() const { return from == to; }
-        RoomEvents::const_iterator begin() const { return from; }
-        RoomEvents::const_iterator end() const { return to; }
-        RoomEvents::iterator begin() { return from; }
-        RoomEvents::iterator end() { return to; }
-    };
-
     class StateEventBase: public RoomEvent
     {
         public:
@@ -273,10 +221,18 @@ namespace QMatrixClient
             explicit StateEventBase(Type type)
                 : RoomEvent(type)
             { }
-            ~StateEventBase() override = 0;
+            ~StateEventBase() override = default;
 
             virtual bool repeatsState() const;
     };
+    using StateEventPtr = event_ptr_tt<StateEventBase>;
+    using StateEvents = EventsArray<StateEventBase>;
+
+    namespace _impl
+    {
+        template <>
+        StateEventPtr doMakeEvent<StateEventBase>(const QJsonObject& obj);
+    }
 
     template <typename ContentT>
     struct Prev
diff --git a/lib/jobs/generated/message_pagination.cpp b/lib/jobs/generated/message_pagination.cpp
new file mode 100644
index 00000000..f89ccd03
--- /dev/null
+++ b/lib/jobs/generated/message_pagination.cpp
@@ -0,0 +1,76 @@
+/******************************************************************************
+ * THIS FILE IS GENERATED - ANY EDITS WILL BE OVERWRITTEN
+ */
+
+#include "message_pagination.h"
+
+#include "converters.h"
+
+#include <QtCore/QStringBuilder>
+
+using namespace QMatrixClient;
+
+static const auto basePath = QStringLiteral("/_matrix/client/r0");
+
+class GetRoomEventsJob::Private
+{
+    public:
+        QString begin;
+        QString end;
+        RoomEvents chunk;
+};
+
+BaseJob::Query queryToGetRoomEvents(const QString& from, const QString& to, const QString& dir, int limit, const QString& filter)
+{
+    BaseJob::Query _q;
+    _q.addQueryItem("from", from);
+    if (!to.isEmpty())
+        _q.addQueryItem("to", to);
+    _q.addQueryItem("dir", dir);
+    _q.addQueryItem("limit", QString("%1").arg(limit));
+    if (!filter.isEmpty())
+        _q.addQueryItem("filter", filter);
+    return _q;
+}
+
+QUrl GetRoomEventsJob::makeRequestUrl(QUrl baseUrl, const QString& roomId, const QString& from, const QString& dir, const QString& to, int limit, const QString& filter)
+{
+    return BaseJob::makeRequestUrl(std::move(baseUrl),
+            basePath % "/rooms/" % roomId % "/messages",
+            queryToGetRoomEvents(from, to, dir, limit, filter));
+}
+
+GetRoomEventsJob::GetRoomEventsJob(const QString& roomId, const QString& from, const QString& dir, const QString& to, int limit, const QString& filter)
+    : BaseJob(HttpVerb::Get, "GetRoomEventsJob",
+        basePath % "/rooms/" % roomId % "/messages",
+        queryToGetRoomEvents(from, to, dir, limit, filter))
+    , d(new Private)
+{
+}
+
+GetRoomEventsJob::~GetRoomEventsJob() = default;
+
+const QString& GetRoomEventsJob::begin() const
+{
+    return d->begin;
+}
+
+const QString& GetRoomEventsJob::end() const
+{
+    return d->end;
+}
+
+RoomEvents&& GetRoomEventsJob::chunk()
+{
+    return std::move(d->chunk);
+}
+
+BaseJob::Status GetRoomEventsJob::parseJson(const QJsonDocument& data)
+{
+    auto json = data.object();
+    d->begin = fromJson<QString>(json.value("start"));
+    d->end = fromJson<QString>(json.value("end"));
+    d->chunk = fromJson<RoomEvents>(json.value("chunk"));
+    return Success;
+}
+
diff --git a/lib/jobs/generated/message_pagination.h b/lib/jobs/generated/message_pagination.h
new file mode 100644
index 00000000..b8588ad1
--- /dev/null
+++ b/lib/jobs/generated/message_pagination.h
@@ -0,0 +1,40 @@
+/******************************************************************************
+ * THIS FILE IS GENERATED - ANY EDITS WILL BE OVERWRITTEN
+ */
+
+#pragma once
+
+#include "../basejob.h"
+
+#include "events/event.h"
+
+
+namespace QMatrixClient
+{
+    // Operations
+
+    class GetRoomEventsJob : public BaseJob
+    {
+        public:
+            /** Construct a URL out of baseUrl and usual parameters passed to
+             * GetRoomEventsJob. This function can be used when
+             * a URL for GetRoomEventsJob is necessary but the job
+             * itself isn't.
+             */
+            static QUrl makeRequestUrl(QUrl baseUrl, const QString& roomId, const QString& from, const QString& dir, const QString& to = {}, int limit = {}, const QString& filter = {});
+
+            explicit GetRoomEventsJob(const QString& roomId, const QString& from, const QString& dir, const QString& to = {}, int limit = {}, const QString& filter = {});
+            ~GetRoomEventsJob() override;
+
+            const QString& begin() const;
+            const QString& end() const;
+            RoomEvents&& chunk();
+
+        protected:
+            Status parseJson(const QJsonDocument& data) override;
+
+        private:
+            class Private;
+            QScopedPointer<Private> d;
+    };
+} // namespace QMatrixClient
diff --git a/lib/jobs/roommessagesjob.cpp b/lib/jobs/roommessagesjob.cpp
deleted file mode 100644
index e5568f17..00000000
--- a/lib/jobs/roommessagesjob.cpp
+++ /dev/null
@@ -1,65 +0,0 @@
-/******************************************************************************
- * Copyright (C) 2016 Felix Rohrbach <kde@fxrh.de>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
- */
-
-#include "roommessagesjob.h"
-
-using namespace QMatrixClient;
-
-class RoomMessagesJob::Private
-{
-    public:
-        RoomEvents events;
-        QString end;
-};
-
-RoomMessagesJob::RoomMessagesJob(const QString& roomId, const QString& from,
-                                 int limit, FetchDirection dir)
-    : BaseJob(HttpVerb::Get, "RoomMessagesJob",
-              QStringLiteral("/_matrix/client/r0/rooms/%1/messages").arg(roomId),
-              Query(
-                { { "from", from }
-                , { "dir", dir == FetchDirection::Backward ? "b" : "f" }
-                , { "limit", QString::number(limit) }
-                }))
-    , d(new Private)
-{
-    qCDebug(JOBS) << "Room messages query:" << query().toString(QUrl::PrettyDecoded);
-}
-
-RoomMessagesJob::~RoomMessagesJob()
-{
-    delete d;
-}
-
-RoomEvents&& RoomMessagesJob::releaseEvents()
-{
-    return move(d->events);
-}
-
-QString RoomMessagesJob::end() const
-{
-    return d->end;
-}
-
-BaseJob::Status RoomMessagesJob::parseJson(const QJsonDocument& data)
-{
-    const auto obj = data.object();
-    d->events.fromJson(obj, "chunk");
-    d->end = obj.value("end").toString();
-    return Success;
-}
diff --git a/lib/jobs/roommessagesjob.h b/lib/jobs/roommessagesjob.h
deleted file mode 100644
index 7b3fd9c9..00000000
--- a/lib/jobs/roommessagesjob.h
+++ /dev/null
@@ -1,47 +0,0 @@
-/******************************************************************************
- * Copyright (C) 2016 Felix Rohrbach <kde@fxrh.de>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
- */
-
-#pragma once
-
-#include "basejob.h"
-
-#include "../events/event.h"
-
-namespace QMatrixClient
-{
-    enum class FetchDirection { Backward, Forward };
-
-    class RoomMessagesJob: public BaseJob
-    {
-        public:
-            RoomMessagesJob(const QString& roomId, const QString& from,
-                            int limit = 10,
-                            FetchDirection dir = FetchDirection::Backward);
-            virtual ~RoomMessagesJob();
-
-            RoomEvents&& releaseEvents();
-            QString end() const;
-
-        protected:
-            Status parseJson(const QJsonDocument& data) override;
-
-        private:
-            class Private;
-            Private* d;
-    };
-}  // namespace QMatrixClient
diff --git a/lib/jobs/syncjob.cpp b/lib/jobs/syncjob.cpp
index 435dfd0e..a739ea0d 100644
--- a/lib/jobs/syncjob.cpp
+++ b/lib/jobs/syncjob.cpp
@@ -54,11 +54,17 @@ SyncDataList&& SyncData::takeRoomData()
     return std::move(roomData);
 }
 
-SyncBatch<Event>&& SyncData::takeAccountData()
+Events&& SyncData::takeAccountData()
 {
     return std::move(accountData);
 }
 
+template <typename EventsArrayT, typename StrT>
+inline EventsArrayT load(const QJsonObject& batches, StrT keyName)
+{
+    return fromJson<EventsArrayT>(batches[keyName].toObject().value("events"));
+}
+
 BaseJob::Status SyncJob::parseJson(const QJsonDocument& data)
 {
     return d.parseJson(data);
@@ -71,7 +77,7 @@ BaseJob::Status SyncData::parseJson(const QJsonDocument &data)
     auto json = data.object();
     nextBatch_ = json.value("next_batch").toString();
     // TODO: presence
-    accountData.fromJson(json);
+    accountData = load<Events>(json, "account_data");
 
     QJsonObject rooms = json.value("rooms").toObject();
     JoinStates::Int ii = 1; // ii is used to make a JoinState value
@@ -96,33 +102,26 @@ SyncRoomData::SyncRoomData(const QString& roomId_, JoinState joinState_,
                            const QJsonObject& room_)
     : roomId(roomId_)
     , joinState(joinState_)
-    , state(joinState == JoinState::Invite ? "invite_state" : "state")
-    , timeline("timeline")
-    , ephemeral("ephemeral")
-    , accountData("account_data")
+    , state(load<StateEvents>(room_,
+                joinState == JoinState::Invite ? "invite_state" : "state"))
 {
     switch (joinState) {
-        case JoinState::Invite:
-            state.fromJson(room_);
-            break;
         case JoinState::Join:
-            state.fromJson(room_);
-            timeline.fromJson(room_);
-            ephemeral.fromJson(room_);
-            accountData.fromJson(room_);
-            break;
+            ephemeral = load<Events>(room_, "ephemeral");
+            accountData = load<Events>(room_, "account_data");
+            // [[fallthrough]]
         case JoinState::Leave:
-            state.fromJson(room_);
-            timeline.fromJson(room_);
+        {
+            timeline = load<RoomEvents>(room_, "timeline");
+            auto timelineJson = room_.value("timeline").toObject();
+            timelineLimited = timelineJson.value("limited").toBool();
+            timelinePrevBatch = timelineJson.value("prev_batch").toString();
+
             break;
-    default:
-        qCWarning(SYNCJOB) << "SyncRoomData: Unknown JoinState value, ignoring:" << int(joinState);
+        }
+        default: /* nothing on top of state */;
     }
 
-    auto timelineJson = room_.value("timeline").toObject();
-    timelineLimited = timelineJson.value("limited").toBool();
-    timelinePrevBatch = timelineJson.value("prev_batch").toString();
-
     auto unreadJson = room_.value("unread_notifications").toObject();
     unreadCount = unreadJson.value(UnreadCountKey).toInt(-2);
     highlightCount = unreadJson.value("highlight_count").toInt();
diff --git a/lib/jobs/syncjob.h b/lib/jobs/syncjob.h
index 919060be..b12f9fff 100644
--- a/lib/jobs/syncjob.h
+++ b/lib/jobs/syncjob.h
@@ -26,30 +26,15 @@
 
 namespace QMatrixClient
 {
-    template <typename EventT>
-    class SyncBatch : public EventsBatch<EventT>
-    {
-        public:
-            explicit SyncBatch(QString k) : jsonKey(std::move(k)) { }
-            void fromJson(const QJsonObject& roomContents)
-            {
-                EventsBatch<EventT>::fromJson(
-                            roomContents[jsonKey].toObject(), "events");
-            }
-
-        private:
-            QString jsonKey;
-    };
-
     class SyncRoomData
     {
         public:
             QString roomId;
             JoinState joinState;
-            SyncBatch<RoomEvent> state;
-            SyncBatch<RoomEvent> timeline;
-            SyncBatch<Event> ephemeral;
-            SyncBatch<Event> accountData;
+            StateEvents state;
+            RoomEvents timeline;
+            Events ephemeral;
+            Events accountData;
 
             bool timelineLimited;
             QString timelinePrevBatch;
@@ -71,13 +56,13 @@ namespace QMatrixClient
     {
         public:
             BaseJob::Status parseJson(const QJsonDocument &data);
-            SyncBatch<Event>&& takeAccountData();
+            Events&& takeAccountData();
             SyncDataList&& takeRoomData();
             QString nextBatch() const;
 
         private:
             QString nextBatch_;
-            SyncBatch<Event> accountData { "account_data" };
+            Events accountData;
             SyncDataList roomData;
     };
 
diff --git a/lib/room.cpp b/lib/room.cpp
index 5771c51d..6c708a42 100644
--- a/lib/room.cpp
+++ b/lib/room.cpp
@@ -25,6 +25,7 @@
 #include "jobs/generated/receipts.h"
 #include "jobs/generated/redaction.h"
 #include "jobs/generated/account-data.h"
+#include "jobs/generated/message_pagination.h"
 #include "jobs/setroomstatejob.h"
 #include "events/simplestateevents.h"
 #include "events/roomavatarevent.h"
@@ -33,7 +34,6 @@
 #include "events/receiptevent.h"
 #include "events/redactionevent.h"
 #include "jobs/sendeventjob.h"
-#include "jobs/roommessagesjob.h"
 #include "jobs/mediathumbnailjob.h"
 #include "jobs/downloadfilejob.h"
 #include "jobs/postreadmarkersjob.h"
@@ -112,7 +112,7 @@ class Room::Private
         TagsMap tags;
         QHash<QString, AccountDataMap> accountData;
         QString prevBatch;
-        QPointer<RoomMessagesJob> roomMessagesJob;
+        QPointer<GetRoomEventsJob> eventsHistoryJob;
 
         struct FileTransferPrivateInfo
         {
@@ -1036,21 +1036,31 @@ void Room::updateData(SyncRoomData&& data)
     for (auto&& event: data.accountData)
         processAccountDataEvent(move(event));
 
+    bool emitNamesChanged = false;
     if (!data.state.empty())
     {
         et.restart();
-        processStateEvents(data.state);
-        qCDebug(PROFILER) << "*** Room::processStateEvents(state):"
+        for (const auto& e: data.state)
+            emitNamesChanged |= processStateEvent(*e);
+
+        qCDebug(PROFILER) << "*** Room::processStateEvents():"
                           << data.state.size() << "event(s)," << et;
     }
     if (!data.timeline.empty())
     {
         et.restart();
         // State changes can arrive in a timeline event; so check those.
-        processStateEvents(data.timeline);
+        for (const auto& e: data.timeline)
+            emitNamesChanged |= processStateEvent(*e);
         qCDebug(PROFILER) << "*** Room::processStateEvents(timeline):"
                           << data.timeline.size() << "event(s)," << et;
+    }
+    if (emitNamesChanged)
+        emit namesChanged(this);
+    d->updateDisplayname();
 
+    if (!data.timeline.empty())
+    {
         et.restart();
         d->addNewMessageEvents(move(data.timeline));
         qCDebug(PROFILER) << "*** Room::addNewMessageEvents():" << et;
@@ -1122,13 +1132,13 @@ void Room::getPreviousContent(int limit)
 
 void Room::Private::getPreviousContent(int limit)
 {
-    if( !isJobRunning(roomMessagesJob) )
+    if( !isJobRunning(eventsHistoryJob) )
     {
-        roomMessagesJob =
-                connection->callApi<RoomMessagesJob>(id, prevBatch, limit);
-        connect( roomMessagesJob, &RoomMessagesJob::success, [=] {
-            prevBatch = roomMessagesJob->end();
-            addHistoricalMessageEvents(roomMessagesJob->releaseEvents());
+        eventsHistoryJob =
+            connection->callApi<GetRoomEventsJob>(id, prevBatch, "b", "", limit);
+        connect( eventsHistoryJob, &BaseJob::success, q, [=] {
+            prevBatch = eventsHistoryJob->end();
+            addHistoricalMessageEvents(eventsHistoryJob->chunk());
         });
     }
 }
@@ -1450,107 +1460,95 @@ void Room::Private::addHistoricalMessageEvents(RoomEvents&& events)
     Q_ASSERT(timeline.size() == timelineSize + insertedSize);
 }
 
-void Room::processStateEvents(const RoomEvents& events)
+bool Room::processStateEvent(const RoomEvent& e)
 {
-    bool emitNamesChanged = false;
-    for (const auto& e: events)
+    switch (e.type())
     {
-        switch (e->type())
-        {
-            case EventType::RoomName: {
-                auto* nameEvent = weakPtr<const RoomNameEvent>(e);
-                d->name = nameEvent->name();
-                qCDebug(MAIN) << "Room name updated:" << d->name;
-                emitNamesChanged = true;
-                break;
-            }
-            case EventType::RoomAliases: {
-                auto* aliasesEvent = weakPtr<const RoomAliasesEvent>(e);
-                d->aliases = aliasesEvent->aliases();
-                qCDebug(MAIN) << "Room aliases updated:" << d->aliases;
-                emitNamesChanged = true;
-                break;
-            }
-            case EventType::RoomCanonicalAlias: {
-                auto* aliasEvent = weakPtr<const RoomCanonicalAliasEvent>(e);
-                d->canonicalAlias = aliasEvent->alias();
-                setObjectName(d->canonicalAlias);
-                qCDebug(MAIN) << "Room canonical alias updated:" << d->canonicalAlias;
-                emitNamesChanged = true;
-                break;
-            }
-            case EventType::RoomTopic: {
-                auto* topicEvent = weakPtr<const RoomTopicEvent>(e);
-                d->topic = topicEvent->topic();
-                qCDebug(MAIN) << "Room topic updated:" << d->topic;
-                emit topicChanged();
-                break;
+        case EventType::RoomName: {
+            d->name = static_cast<const RoomNameEvent&>(e).name();
+            qCDebug(MAIN) << "Room name updated:" << d->name;
+            return true;
+        }
+        case EventType::RoomAliases: {
+            d->aliases = static_cast<const RoomAliasesEvent&>(e).aliases();
+            qCDebug(MAIN) << "Room aliases updated:" << d->aliases;
+            return true;
+        }
+        case EventType::RoomCanonicalAlias: {
+            d->canonicalAlias =
+                    static_cast<const RoomCanonicalAliasEvent&>(e).alias();
+            setObjectName(d->canonicalAlias);
+            qCDebug(MAIN) << "Room canonical alias updated:" << d->canonicalAlias;
+            return true;
+        }
+        case EventType::RoomTopic: {
+            d->topic = static_cast<const RoomTopicEvent&>(e).topic();
+            qCDebug(MAIN) << "Room topic updated:" << d->topic;
+            emit topicChanged();
+            return false;
+        }
+        case EventType::RoomAvatar: {
+            const auto& avatarEventContent =
+                    static_cast<const RoomAvatarEvent&>(e).content();
+            if (d->avatar.updateUrl(avatarEventContent.url))
+            {
+                qCDebug(MAIN) << "Room avatar URL updated:"
+                              << avatarEventContent.url.toString();
+                emit avatarChanged();
             }
-            case EventType::RoomAvatar: {
-                const auto& avatarEventContent =
-                        weakPtr<const RoomAvatarEvent>(e)->content();
-                if (d->avatar.updateUrl(avatarEventContent.url))
+            return false;
+        }
+        case EventType::RoomMember: {
+            const auto& memberEvent = static_cast<const RoomMemberEvent&>(e);
+            auto* u = user(memberEvent.userId());
+            u->processEvent(memberEvent, this);
+            if (u == localUser() && memberJoinState(u) == JoinState::Invite
+                    && memberEvent.isDirect())
+                connection()->addToDirectChats(this,
+                                user(memberEvent.senderId()));
+
+            if( memberEvent.membership() == MembershipType::Join )
+            {
+                if (memberJoinState(u) != JoinState::Join)
                 {
-                    qCDebug(MAIN) << "Room avatar URL updated:"
-                                  << avatarEventContent.url.toString();
-                    emit avatarChanged();
+                    d->insertMemberIntoMap(u);
+                    connect(u, &User::nameAboutToChange, this,
+                        [=] (QString newName, QString, const Room* context) {
+                            if (context == this)
+                                emit memberAboutToRename(u, newName);
+                        });
+                    connect(u, &User::nameChanged, this,
+                        [=] (QString, QString oldName, const Room* context) {
+                            if (context == this)
+                                d->renameMember(u, oldName);
+                        });
+                    emit userAdded(u);
                 }
-                break;
             }
-            case EventType::RoomMember: {
-                auto* memberEvent = weakPtr<const RoomMemberEvent>(e);
-                auto u = user(memberEvent->userId());
-                u->processEvent(memberEvent, this);
-                if (u == localUser() && memberJoinState(u) == JoinState::Invite
-                        && memberEvent->isDirect())
-                    connection()->addToDirectChats(this,
-                                    user(memberEvent->senderId()));
-
-                if( memberEvent->membership() == MembershipType::Join )
-                {
-                    if (memberJoinState(u) != JoinState::Join)
-                    {
-                        d->insertMemberIntoMap(u);
-                        connect(u, &User::nameAboutToChange, this,
-                            [=] (QString newName, QString, const Room* context) {
-                                if (context == this)
-                                    emit memberAboutToRename(u, newName);
-                            });
-                        connect(u, &User::nameChanged, this,
-                            [=] (QString, QString oldName, const Room* context) {
-                                if (context == this)
-                                    d->renameMember(u, oldName);
-                            });
-                        emit userAdded(u);
-                    }
-                }
-                else if( memberEvent->membership() == MembershipType::Leave )
+            else if( memberEvent.membership() == MembershipType::Leave )
+            {
+                if (memberJoinState(u) == JoinState::Join)
                 {
-                    if (memberJoinState(u) == JoinState::Join)
-                    {
-                        if (!d->membersLeft.contains(u))
-                            d->membersLeft.append(u);
-                        d->removeMemberFromMap(u->name(this), u);
-                        emit userRemoved(u);
-                    }
+                    if (!d->membersLeft.contains(u))
+                        d->membersLeft.append(u);
+                    d->removeMemberFromMap(u->name(this), u);
+                    emit userRemoved(u);
                 }
-                break;
             }
-            case EventType::RoomEncryption:
-            {
-                d->encryptionAlgorithm =
-                        weakPtr<const EncryptionEvent>(e)->algorithm();
-                qCDebug(MAIN) << "Encryption switched on in" << displayName();
-                emit encryption();
-                break;
-            }
-            default: /* Ignore events of other types */;
+            return false;
         }
+        case EventType::RoomEncryption:
+        {
+            d->encryptionAlgorithm =
+                    static_cast<const EncryptionEvent&>(e).algorithm();
+            qCDebug(MAIN) << "Encryption switched on in" << displayName();
+            emit encryption();
+            return false;
+        }
+        default:
+            /* Ignore events of other types */
+            return false;
     }
-    if (emitNamesChanged) {
-        emit namesChanged(this);
-    }
-    d->updateDisplayname();
 }
 
 void Room::processEphemeralEvent(EventPtr&& event)
diff --git a/lib/room.h b/lib/room.h
index 288db5fb..7b4b3578 100644
--- a/lib/room.h
+++ b/lib/room.h
@@ -408,13 +408,14 @@ namespace QMatrixClient
             void fileTransferCancelled(QString id);
 
         protected:
-            virtual void processStateEvents(const RoomEvents& events);
+            /// Returns true if any of room names/aliases has changed
+            virtual bool processStateEvent(const RoomEvent& e);
             virtual void processEphemeralEvent(EventPtr&& event);
             virtual void processAccountDataEvent(EventPtr&& event);
-            virtual void onAddNewTimelineEvents(timeline_iter_t from) { }
-            virtual void onAddHistoricalTimelineEvents(rev_iter_t from) { }
-            virtual void onRedaction(const RoomEvent& prevEvent,
-                                     const RoomEvent& after) { }
+            virtual void onAddNewTimelineEvents(timeline_iter_t /*from*/) { }
+            virtual void onAddHistoricalTimelineEvents(rev_iter_t /*from*/) { }
+            virtual void onRedaction(const RoomEvent& /*prevEvent*/,
+                                     const RoomEvent& /*after*/) { }
 
         private:
             class Private;
diff --git a/lib/user.cpp b/lib/user.cpp
index 91b340d5..89e324f9 100644
--- a/lib/user.cpp
+++ b/lib/user.cpp
@@ -358,19 +358,20 @@ QUrl User::avatarUrl(const Room* room) const
     return avatarObject(room).url();
 }
 
-void User::processEvent(const RoomMemberEvent* event, const Room* room)
+void User::processEvent(const RoomMemberEvent& event, const Room* room)
 {
-    if (event->membership() != MembershipType::Invite &&
-            event->membership() != MembershipType::Join)
+    Q_ASSERT(room);
+    if (event.membership() != MembershipType::Invite &&
+            event.membership() != MembershipType::Join)
         return;
 
     auto aboutToEnter = room->memberJoinState(this) == JoinState::Leave &&
-            (event->membership() == MembershipType::Join ||
-             event->membership() == MembershipType::Invite);
+            (event.membership() == MembershipType::Join ||
+             event.membership() == MembershipType::Invite);
     if (aboutToEnter)
         ++d->totalRooms;
 
-    auto newName = event->displayName();
+    auto newName = event.displayName();
     // `bridged` value uses the same notification signal as the name;
     // it is assumed that first setting of the bridge occurs together with
     // the first setting of the name, and further bridge updates are
@@ -390,17 +391,17 @@ void User::processEvent(const RoomMemberEvent* event, const Room* room)
         }
         newName.truncate(match.capturedStart(0));
     }
-    if (event->prevContent())
+    if (event.prevContent())
     {
         // FIXME: the hint doesn't work for bridged users
         auto oldNameHint =
-                d->nameForRoom(room, event->prevContent()->displayName);
+                d->nameForRoom(room, event.prevContent()->displayName);
         updateName(newName, oldNameHint, room);
-        updateAvatarUrl(event->avatarUrl(),
-                        d->avatarUrlForRoom(room, event->prevContent()->avatarUrl),
+        updateAvatarUrl(event.avatarUrl(),
+                        d->avatarUrlForRoom(room, event.prevContent()->avatarUrl),
                         room);
     } else {
         updateName(newName, room);
-        updateAvatarUrl(event->avatarUrl(), d->avatarUrlForRoom(room), room);
+        updateAvatarUrl(event.avatarUrl(), d->avatarUrlForRoom(room), room);
     }
 }
diff --git a/lib/user.h b/lib/user.h
index 8ac96539..76aa672f 100644
--- a/lib/user.h
+++ b/lib/user.h
@@ -103,8 +103,7 @@ namespace QMatrixClient
             QString avatarMediaId(const Room* room = nullptr) const;
             QUrl avatarUrl(const Room* room = nullptr) const;
 
-            void processEvent(const RoomMemberEvent* event,
-                              const Room* r = nullptr);
+            void processEvent(const RoomMemberEvent& event, const Room* r);
 
         public slots:
             void rename(const QString& newName);
diff --git a/lib/util.h b/lib/util.h
index 55f3af6a..f65b05a3 100644
--- a/lib/util.h
+++ b/lib/util.h
@@ -58,6 +58,37 @@ namespace QMatrixClient
     static void qAsConst(const T &&) Q_DECL_EQ_DELETE;
 #endif
 
+    /** An abstraction over a pair of iterators
+     * This is a very basic range type over a container with iterators that
+     * are at least ForwardIterators. Inspired by Ranges TS.
+     */
+    template <typename ArrayT>
+    class Range
+    {
+            // Looking forward for Ranges TS to produce something (in C++23?..)
+            using iterator = typename ArrayT::iterator;
+            using const_iterator = typename ArrayT::const_iterator;
+            using size_type = typename ArrayT::size_type;
+        public:
+            Range(ArrayT& arr) : from(std::begin(arr)), to(std::end(arr)) { }
+            Range(iterator from, iterator to) : from(from), to(to) { }
+
+            size_type size() const
+            {
+                Q_ASSERT(std::distance(from, to) >= 0);
+                return size_type(std::distance(from, to));
+            }
+            bool empty() const { return from == to; }
+            const_iterator begin() const { return from; }
+            const_iterator end() const { return to; }
+            iterator begin() { return from; }
+            iterator end() { return to; }
+
+        private:
+            iterator from;
+            iterator to;
+    };
+
     /** A guard pointer that disconnects an interested object upon destruction
      * It's almost QPointer<> except that you have to initialise it with one
      * more additional parameter - a pointer to a QObject that will be