Merge branch 'master' into kitsune-gtad

12 files changed, 205 insertions, 90 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 094ec488..b966476f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -40,7 +40,7 @@ foreach (FLAG all "" pedantic extra error=return-type no-unused-parameter no-gnu
     endif ()
 endforeach ()
 
-find_package(Qt5 5.5.1 REQUIRED Network Gui)
+find_package(Qt5 5.4.1 REQUIRED Network Gui)
 get_filename_component(Qt5_Prefix "${Qt5_DIR}/../../../.." ABSOLUTE)
 
 message( STATUS )
diff --git a/lib/avatar.cpp b/lib/avatar.cpp
index 1ff2aae1..7e6dc50b 100644
--- a/lib/avatar.cpp
+++ b/lib/avatar.cpp
@@ -1,3 +1,5 @@
+#include <utility>
+
 /******************************************************************************
  * Copyright (C) 2017 Kitsune Ral <kitsune-ral@users.sf.net>
  *
@@ -26,12 +28,13 @@
 #include <QtCore/QPointer>
 
 using namespace QMatrixClient;
+using std::move;
 
 class Avatar::Private
 {
     public:
         explicit Private(QIcon di, QUrl url = {})
-            : _defaultIcon(di), _url(url)
+            : _defaultIcon(move(di)), _url(move(url))
         { }
         QImage get(Connection* connection, QSize size,
                    get_callback_t callback) const;
@@ -51,7 +54,6 @@ class Avatar::Private
         mutable QPointer<MediaThumbnailJob> _thumbnailRequest = nullptr;
         mutable QPointer<BaseJob> _uploadRequest = nullptr;
         mutable std::vector<get_callback_t> callbacks;
-        mutable get_callback_t uploadCallback;
 };
 
 Avatar::Avatar(QIcon defaultIcon)
@@ -71,13 +73,13 @@ Avatar& Avatar::operator=(Avatar&&) = default;
 QImage Avatar::get(Connection* connection, int dimension,
                    get_callback_t callback) const
 {
-    return d->get(connection, {dimension, dimension}, callback);
+    return d->get(connection, {dimension, dimension}, move(callback));
 }
 
 QImage Avatar::get(Connection* connection, int width, int height,
                    get_callback_t callback) const
 {
-    return d->get(connection, {width, height}, callback);
+    return d->get(connection, {width, height}, move(callback));
 }
 
 bool Avatar::upload(Connection* connection, const QString& fileName,
@@ -85,7 +87,7 @@ bool Avatar::upload(Connection* connection, const QString& fileName,
 {
     if (isJobRunning(d->_uploadRequest))
         return false;
-    return d->upload(connection->uploadFile(fileName), callback);
+    return d->upload(connection->uploadFile(fileName), move(callback));
 }
 
 bool Avatar::upload(Connection* connection, QIODevice* source,
@@ -93,7 +95,7 @@ bool Avatar::upload(Connection* connection, QIODevice* source,
 {
     if (isJobRunning(d->_uploadRequest) || !source->isReadable())
         return false;
-    return d->upload(connection->uploadContent(source), callback);
+    return d->upload(connection->uploadContent(source), move(callback));
 }
 
 QString Avatar::mediaId() const
@@ -104,6 +106,11 @@ QString Avatar::mediaId() const
 QImage Avatar::Private::get(Connection* connection, QSize size,
                             get_callback_t callback) const
 {
+    if (!callback)
+    {
+        qCCritical(MAIN) << "Null callbacks are not allowed in Avatar::get";
+        Q_ASSERT(false);
+    }
     // FIXME: Alternating between longer-width and longer-height requests
     // is a sure way to trick the below code into constantly getting another
     // image from the server because the existing one is alleged unsatisfactory.
@@ -116,16 +123,19 @@ QImage Avatar::Private::get(Connection* connection, QSize size,
         _requestedSize = size;
         if (isJobRunning(_thumbnailRequest))
             _thumbnailRequest->abandon();
-        callbacks.emplace_back(std::move(callback));
+        if (callback)
+            callbacks.emplace_back(move(callback));
         _thumbnailRequest = connection->getThumbnail(_url, size);
-        QObject::connect( _thumbnailRequest, &MediaThumbnailJob::success, [this]
-        {
-            _fetched = true;
-            _originalImage = _thumbnailRequest->scaledThumbnail(_requestedSize);
-            _scaledImages.clear();
-            for (auto n: callbacks)
-                n();
-        });
+        QObject::connect( _thumbnailRequest, &MediaThumbnailJob::success,
+            _thumbnailRequest, [this] {
+                _fetched = true;
+                _originalImage =
+                        _thumbnailRequest->scaledThumbnail(_requestedSize);
+                _scaledImages.clear();
+                for (const auto& n: callbacks)
+                    n();
+                callbacks.clear();
+            });
     }
 
     if( _originalImage.isNull() )
@@ -137,7 +147,7 @@ QImage Avatar::Private::get(Connection* connection, QSize size,
         _defaultIcon.paint(&p, { QPoint(), _defaultIcon.actualSize(size) });
     }
 
-    for (auto p: _scaledImages)
+    for (const auto& p: _scaledImages)
         if (p.first == size)
             return p.second;
     auto result = _originalImage.scaled(size,
@@ -151,7 +161,7 @@ bool Avatar::Private::upload(UploadContentJob* job, upload_callback_t callback)
     _uploadRequest = job;
     if (!isJobRunning(_uploadRequest))
         return false;
-    _uploadRequest->connect(_uploadRequest, &BaseJob::success,
+    _uploadRequest->connect(_uploadRequest, &BaseJob::success, _uploadRequest,
                             [job,callback] { callback(job->contentUri()); });
     return true;
 }
diff --git a/lib/connection.cpp b/lib/connection.cpp
index 600ab396..5f930d57 100644
--- a/lib/connection.cpp
+++ b/lib/connection.cpp
@@ -84,7 +84,7 @@ class Connection::Private
         QVector<QString> roomIdsToForget;
         QMap<QString, User*> userMap;
         DirectChatsMap directChats;
-        QHash<QString, QVariantHash> accountData;
+        QHash<QString, AccountDataMap> accountData;
         QString userId;
 
         SyncJob* syncJob = nullptr;
@@ -336,7 +336,7 @@ void Connection::onSyncSuccess(SyncData &&data) {
             continue;
         }
         d->accountData[accountEvent->jsonType()] =
-                accountEvent->contentJson().toVariantHash();
+                fromJson<AccountDataMap>(accountEvent->contentJson());
         emit accountDataChanged(accountEvent->jsonType());
     }
 }
@@ -590,6 +590,7 @@ Room* Connection::invitation(const QString& roomId) const
 
 User* Connection::user(const QString& userId)
 {
+    Q_ASSERT(userId.startsWith('@') && userId.contains(':'));
     if( d->userMap.contains(userId) )
         return d->userMap.value(userId);
     auto* user = userFactory(this, userId);
@@ -657,7 +658,7 @@ bool Connection::hasAccountData(const QString& type) const
     return d->accountData.contains(type);
 }
 
-QVariantHash Connection::accountData(const QString& type) const
+Connection::AccountDataMap Connection::accountData(const QString& type) const
 {
     return d->accountData.value(type);
 }
@@ -847,7 +848,7 @@ void Connection::setHomeserver(const QUrl& url)
     emit homeserverChanged(homeserver());
 }
 
-static constexpr int CACHE_VERSION_MAJOR = 7;
+static constexpr int CACHE_VERSION_MAJOR = 8;
 static constexpr int CACHE_VERSION_MINOR = 0;
 
 void Connection::saveState(const QUrl &toFile) const
@@ -909,7 +910,7 @@ void Connection::saveState(const QUrl &toFile) const
         for (auto it = d->accountData.begin(); it != d->accountData.end(); ++it)
             accountDataEvents.append(QJsonObject {
                 {"type", it.key()},
-                {"content", QJsonObject::fromVariantHash(it.value())}
+                {"content", QMatrixClient::toJson(it.value())}
             });
         rootObj.insert("account_data",
             QJsonObject {{ QStringLiteral("events"), accountDataEvents }});
diff --git a/lib/connection.h b/lib/connection.h
index be414931..839371ef 100644
--- a/lib/connection.h
+++ b/lib/connection.h
@@ -66,6 +66,10 @@ namespace QMatrixClient
 
             using DirectChatsMap = QMultiHash<const User*, QString>;
 
+            using AccountDataMap = std::conditional_t<
+                QT_VERSION >= QT_VERSION_CHECK(5, 5, 0),
+                QVariantHash, QVariantMap>;
+
             enum RoomVisibility { PublishRoom, UnpublishRoom }; // FIXME: Should go inside CreateRoomJob
 
             explicit Connection(QObject* parent = nullptr);
@@ -88,7 +92,7 @@ namespace QMatrixClient
              * stored on the server. Direct chats map cannot be retrieved
              * using this method _yet_; use directChats() instead.
              */
-            QVariantHash accountData(const QString& type) const;
+            AccountDataMap accountData(const QString& type) const;
 
             /** Get all Invited and Joined rooms grouped by tag
              * \return a hashmap from tag name to a vector of room pointers,
diff --git a/lib/converters.h b/lib/converters.h
index bba298e0..22b22f25 100644
--- a/lib/converters.h
+++ b/lib/converters.h
@@ -21,6 +21,7 @@
 #include <QtCore/QJsonObject>
 #include <QtCore/QJsonArray> // Includes <QtCore/QJsonValue>
 #include <QtCore/QDate>
+#include <QtCore/QVariant>
 
 namespace QMatrixClient
 {
@@ -51,6 +52,18 @@ namespace QMatrixClient
         return QJsonValue(bytes.constData());
     }
 
+    inline QJsonObject toJson(const QVariantMap& map)
+    {
+        return QJsonObject::fromVariantMap(map);
+    }
+
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 5, 0))
+    inline QJsonObject toJson(const QVariantHash& hMap)
+    {
+        return QJsonObject::fromVariantHash(hMap);
+    }
+#endif
+
     template <typename T>
     inline QJsonObject toJson(const QHash<QString, T>& hashMap)
     {
@@ -163,6 +176,24 @@ namespace QMatrixClient
         }
     };
 
+    template <> struct FromJson<QVariantMap>
+    {
+        inline auto operator()(const QJsonValue& jv) const
+        {
+            return jv.toObject().toVariantMap();
+        }
+    };
+
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 5, 0))
+    template <> struct FromJson<QVariantHash>
+    {
+        inline auto operator()(const QJsonValue& jv) const
+        {
+            return jv.toObject().toVariantHash();
+        }
+    };
+#endif
+
     template <typename T> struct FromJson<QHash<QString, T>>
     {
         QHash<QString, T> operator()(const QJsonValue& jv) const
diff --git a/lib/jobs/basejob.cpp b/lib/jobs/basejob.cpp
index 696861fb..2d41650a 100644
--- a/lib/jobs/basejob.cpp
+++ b/lib/jobs/basejob.cpp
@@ -336,39 +336,50 @@ bool checkContentType(const QByteArray& type, const QByteArrayList& patterns)
 
 BaseJob::Status BaseJob::doCheckReply(QNetworkReply* reply) const
 {
-    const auto httpCode =
-            reply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
-
-    if (httpCode == 429) // Qt doesn't know about it yet
-        return { TooManyRequestsError, tr("Too many requests") };
-
-    // Should we check httpCode instead? Maybe even use it in BaseJob::Status?
-    // That would make codes in logs slightly more readable.
-    switch( reply->error() )
+    // QNetworkReply error codes seem to be flawed when it comes to HTTP;
+    // see, e.g., https://github.com/QMatrixClient/libqmatrixclient/issues/200
+    // so check genuine HTTP codes. The below processing is based on
+    // https://en.wikipedia.org/wiki/List_of_HTTP_status_codes
+    const auto httpCodeHeader =
+            reply->attribute(QNetworkRequest::HttpStatusCodeAttribute);
+    if (!httpCodeHeader.isValid()) // Woah, we didn't even get HTTP headers
+        return { NetworkError, reply->errorString() };
+
+    const auto httpCode = httpCodeHeader.toInt();
+    if (httpCode / 100 == 2) // 2xx
     {
-        case QNetworkReply::NoError:
-            if (checkContentType(reply->rawHeader("Content-Type"),
-                                 d->expectedContentTypes))
-                return NoError;
-            else // A warning in the logs might be more proper instead
-                return { IncorrectResponseError,
-                         "Incorrect content type of the response" };
-
-        case QNetworkReply::AuthenticationRequiredError:
-        case QNetworkReply::ContentAccessDenied:
-        case QNetworkReply::ContentOperationNotPermittedError:
-            return { ContentAccessError, reply->errorString() };
-
-        case QNetworkReply::ProtocolInvalidOperationError:
-        case QNetworkReply::UnknownContentError:
-            return { IncorrectRequestError, reply->errorString() };
-
-        case QNetworkReply::ContentNotFoundError:
-            return { NotFoundError, reply->errorString() };
-
-        default:
-            return { NetworkError, reply->errorString() };
+        if (checkContentType(reply->rawHeader("Content-Type"),
+                             d->expectedContentTypes))
+            return NoError;
+        else // A warning in the logs might be more proper instead
+            return { UnexpectedResponseTypeWarning,
+                     "Unexpected content type of the response" };
     }
+
+    return { [httpCode]() -> StatusCode {
+            if (httpCode / 10 == 41)
+                return httpCode == 410 ? IncorrectRequestError : NotFoundError;
+            switch (httpCode)
+            {
+                case 401: case 403: case 407:
+                    return ContentAccessError;
+                case 404:
+                    return NotFoundError;
+                case 400: case 405: case 406: case 426: case 428:
+                case 505:
+                case 494: // Unofficial nginx "Request header too large"
+                case 497: // Unofficial nginx "HTTP request sent to HTTPS port"
+                    return IncorrectRequestError;
+                case 429:
+                    return TooManyRequestsError;
+                case 501: case 510:
+                    return RequestNotImplementedError;
+                case 511:
+                    return NetworkAuthRequiredError;
+                default:
+                    return NetworkError;
+            }
+        }(), reply->errorString() };
 }
 
 BaseJob::Status BaseJob::parseReply(QNetworkReply* reply)
diff --git a/lib/jobs/basejob.h b/lib/jobs/basejob.h
index f243066f..763ef75a 100644
--- a/lib/jobs/basejob.h
+++ b/lib/jobs/basejob.h
@@ -53,6 +53,8 @@ namespace QMatrixClient
             enum StatusCode { NoError = 0 // To be compatible with Qt conventions
                 , Success = 0
                 , Pending = 1
+                , WarningLevel = 20
+                , UnexpectedResponseTypeWarning = 21
                 , Abandoned = 50 //< A very brief period between abandoning and object deletion
                 , ErrorLevel = 100 //< Errors have codes starting from this
                 , NetworkError = 100
@@ -63,6 +65,8 @@ namespace QMatrixClient
                 , IncorrectRequestError
                 , IncorrectResponseError
                 , TooManyRequestsError
+                , RequestNotImplementedError
+                , NetworkAuthRequiredError
                 , UserDefinedError = 200
             };
 
diff --git a/lib/room.cpp b/lib/room.cpp
index edbc9266..1fa9212e 100644
--- a/lib/room.cpp
+++ b/lib/room.cpp
@@ -109,7 +109,7 @@ class Room::Private
         QHash<const User*, QString> lastReadEventIds;
         QString serverReadMarker;
         TagsMap tags;
-        QHash<QString, QVariantHash> accountData;
+        QHash<QString, AccountDataMap> accountData;
         QString prevBatch;
         QPointer<RoomMessagesJob> roomMessagesJob;
 
@@ -302,7 +302,8 @@ QImage Room::avatar(int dimension)
 QImage Room::avatar(int width, int height)
 {
     if (!d->avatar.url().isEmpty())
-        return d->avatar.get(connection(), width, height, [=] { emit avatarChanged(); });
+        return d->avatar.get(connection(), width, height,
+                             [=] { emit avatarChanged(); });
 
     // Use the other side's avatar for 1:1's
     if (d->membersMap.size() == 2)
@@ -637,7 +638,7 @@ bool Room::hasAccountData(const QString& type) const
     return d->accountData.contains(type);
 }
 
-QVariantHash Room::accountData(const QString& type) const
+Room::AccountDataMap Room::accountData(const QString& type) const
 {
     return d->accountData.value(type);
 }
@@ -991,26 +992,32 @@ QString Room::roomMembername(const User* u) const
     if (username.isEmpty())
         return u->id();
 
-    // Get the list of users with the same display name. Most likely,
-    // there'll be one, but there's a chance there are more.
-    if (d->membersMap.count(username) == 1)
-        return username;
+    auto namesakesIt = qAsConst(d->membersMap).find(username);
 
     // We expect a user to be a member of the room - but technically it is
     // possible to invoke roomMemberName() even for non-members. In such case
-    // we return the name _with_ id, to stay on a safe side.
-    // XXX: Causes a storm of false alarms when scrolling through older events
-    // with left users; commented out until we have a proper backtracking of
-    // room state ("room time machine").
-//    if ( !namesakes.contains(u) )
-//    {
-//        qCWarning()
-//            << "Room::roomMemberName(): user" << u->id()
-//            << "is not a member of the room" << id();
-//    }
+    // we return the full name, just in case.
+    if (namesakesIt == d->membersMap.cend())
+        return u->fullName(this);
+
+    auto nextUserIt = namesakesIt + 1;
+    if (nextUserIt == d->membersMap.cend() || nextUserIt.key() != username)
+        return username; // No disambiguation necessary
+
+    // Check if we can get away just attaching the bridge postfix
+    // (extension to the spec)
+    QVector<QString> bridges;
+    for (; namesakesIt != d->membersMap.cend() && namesakesIt.key() == username;
+         ++namesakesIt)
+    {
+        const auto bridgeName = (*namesakesIt)->bridged();
+        if (bridges.contains(bridgeName)) // Two accounts on the same bridge
+            return u->fullName(this); // Disambiguate fully
+        // Don't bother sorting, not so many bridges out there
+        bridges.push_back(bridgeName);
+    }
 
-    // In case of more than one namesake, use the full name to disambiguate
-    return u->fullName(this);
+    return u->rawName(this); // Disambiguate using the bridge postfix only
 }
 
 QString Room::roomMembername(const QString& userId) const
@@ -1653,7 +1660,7 @@ void Room::processAccountDataEvent(EventPtr event)
         }
         default:
             d->accountData[event->jsonType()] =
-                    event->contentJson().toVariantHash();
+                    fromJson<AccountDataMap>(event->contentJson());
             emit accountDataChanged(event->jsonType());
     }
 }
@@ -1795,7 +1802,7 @@ QJsonObject Room::Private::toJson() const
         for (const auto *m : membersMap)
             appendStateEvent(stateEvents, QStringLiteral("m.room.member"),
                 { { QStringLiteral("membership"), QStringLiteral("join") }
-                , { QStringLiteral("displayname"), m->name(q) }
+                , { QStringLiteral("displayname"), m->rawName(q) }
                 , { QStringLiteral("avatar_url"), m->avatarUrl(q).toString() }
             }, m->id());
 
@@ -1816,7 +1823,7 @@ QJsonObject Room::Private::toJson() const
     {
         for (auto it = accountData.begin(); it != accountData.end(); ++it)
             appendEvent(accountDataEvents, it.key(),
-                        QJsonObject::fromVariantHash(it.value()));
+                        QMatrixClient::toJson(it.value()));
     }
     result.insert("account_data", QJsonObject {{ "events", accountDataEvents }});
 
diff --git a/lib/room.h b/lib/room.h
index 39dee8f5..86a7b245 100644
--- a/lib/room.h
+++ b/lib/room.h
@@ -123,6 +123,10 @@ namespace QMatrixClient
             using rev_iter_t = Timeline::const_reverse_iterator;
             using timeline_iter_t = Timeline::const_iterator;
 
+            using AccountDataMap = std::conditional_t<
+                QT_VERSION >= QT_VERSION_CHECK(5, 5, 0),
+                QVariantHash, QVariantMap>;
+
             Room(Connection* connection, QString id, JoinState initialJoinState);
             ~Room() override;
 
@@ -269,7 +273,7 @@ namespace QMatrixClient
              * stored on the server. Tags and read markers cannot be retrieved
              * using this method _yet_.
              */
-            QVariantHash accountData(const QString& type) const;
+            AccountDataMap accountData(const QString& type) const;
 
             QStringList tagNames() const;
             TagsMap tags() const;
diff --git a/lib/user.cpp b/lib/user.cpp
index 6143a061..c4fbfe35 100644
--- a/lib/user.cpp
+++ b/lib/user.cpp
@@ -220,6 +220,12 @@ QString User::name(const Room* room) const
     return d->nameForRoom(room);
 }
 
+QString User::rawName(const Room* room) const
+{
+    return d->bridged.isEmpty() ? name(room) :
+                                  name(room) % " (" % d->bridged % ')';
+}
+
 void User::updateName(const QString& newName, const Room* room)
 {
     updateName(newName, d->nameForRoom(room), room);
@@ -305,7 +311,7 @@ QString User::displayname(const Room* room) const
 {
     auto name = d->nameForRoom(room);
     return name.isEmpty() ? d->userId :
-           room ? room->roomMembername(name) : name;
+           room ? room->roomMembername(this) : name;
 }
 
 QString User::fullName(const Room* room) const
@@ -389,12 +395,12 @@ void User::processEvent(RoomMemberEvent* event, const Room* room)
         // FIXME: the hint doesn't work for bridged users
         auto oldNameHint =
                 d->nameForRoom(room, event->prevContent()->displayName);
-        updateName(event->displayName(), oldNameHint, room);
+        updateName(newName, oldNameHint, room);
         updateAvatarUrl(event->avatarUrl(),
                         d->avatarUrlForRoom(room, event->prevContent()->avatarUrl),
                         room);
     } else {
-        updateName(event->displayName(), room);
+        updateName(newName, room);
         updateAvatarUrl(event->avatarUrl(), d->avatarUrlForRoom(room), room);
     }
 }
diff --git a/lib/user.h b/lib/user.h
index f76f9e0a..f94fbee4 100644
--- a/lib/user.h
+++ b/lib/user.h
@@ -50,24 +50,33 @@ namespace QMatrixClient
 
             /** Get the name chosen by the user
              * This may be empty if the user didn't choose the name or cleared
-             * it.
-             * \sa displayName
+             * it. If the user is bridged, the bridge postfix (such as '(IRC)')
+             * is stripped out. No disambiguation for the room is done.
+             * \sa displayName, rawName
              */
             QString name(const Room* room = nullptr) const;
 
+            /** Get the user name along with the bridge postfix
+             * This function is similar to name() but appends the bridge postfix
+             * (such as '(IRC)') to the user name. No disambiguation is done.
+             * \sa name, displayName
+             */
+            QString rawName(const Room* room = nullptr) const;
+
             /** Get the displayed user name
-             * This method returns the result of name() if its non-empty;
-             * otherwise it returns user id. This is convenient to show a user
-             * name outside of a room context. In a room context, user names
-             * should be disambiguated.
-             * \sa name, id, fullName Room::roomMembername
+             * When \p room is null, this method returns result of name() if
+             * the name is non-empty; otherwise it returns user id.
+             * When \p room is non-null, this call is equivalent to
+             * Room::roomMembername invocation for the user (i.e. the user's
+             * disambiguated room-specific name is returned).
+             * \sa name, id, fullName, Room::roomMembername
              */
             QString displayname(const Room* room = nullptr) const;
 
             /** Get user name and id in one string
              * The constructed string follows the format 'name (id)'
-             * used for users disambiguation in a room context and in other
-             * places.
+             * which the spec recommends for users disambiguation in
+             * a room context and in other places.
              * \sa displayName, Room::roomMembername
              */
             QString fullName(const Room* room = nullptr) const;
diff --git a/lib/util.h b/lib/util.h
index 92198b0b..7ab1e20d 100644
--- a/lib/util.h
+++ b/lib/util.h
@@ -20,6 +20,7 @@
 
 #include <QtCore/QMetaEnum>
 #include <QtCore/QDebug>
+#include <QtCore/QPointer>
 
 #include <functional>
 #include <memory>
@@ -41,6 +42,7 @@ namespace QMatrixClient
     }
 #endif
 
+    /** static_cast<> for unique_ptr's */
     template <typename T1, typename PtrT2>
     inline auto unique_ptr_cast(PtrT2&& p)
     {
@@ -55,5 +57,31 @@ namespace QMatrixClient
     template <typename T>
     static void qAsConst(const T &&) Q_DECL_EQ_DELETE;
 #endif
+
+    /** 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
+     * disconnected from signals of the underlying pointer upon the guard's
+     * destruction.
+     */
+    template <typename T>
+    class ConnectionsGuard : public QPointer<T>
+    {
+        public:
+            ConnectionsGuard(T* publisher, QObject* subscriber)
+                : QPointer<T>(publisher), subscriber(subscriber)
+            { }
+            ~ConnectionsGuard()
+            {
+                if (*this)
+                    (*this)->disconnect(subscriber);
+            }
+            ConnectionsGuard(ConnectionsGuard&&) noexcept = default;
+            ConnectionsGuard& operator=(ConnectionsGuard&&) noexcept = default;
+            using QPointer<T>::operator=;
+
+        private:
+            QObject* subscriber;
+    };
 }  // namespace QMatrixClient