From 00b6103ceeed63238cb8c691163ed8489dd72ddb Mon Sep 17 00:00:00 2001
From: Tobias Fella <fella@posteo.de>
Date: Sat, 15 May 2021 22:44:42 +0200
Subject: Start implementing device key tracking

---
 lib/connection.cpp | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 lib/syncdata.cpp   | 30 ++++++++++++++++++++++
 lib/syncdata.h     | 23 +++++++++++++++++
 3 files changed, 126 insertions(+)

diff --git a/lib/connection.cpp b/lib/connection.cpp
index 1485a347..66590bd8 100644
--- a/lib/connection.cpp
+++ b/lib/connection.cpp
@@ -102,6 +102,13 @@ public:
     QMetaObject::Connection syncLoopConnection {};
     int syncTimeout = -1;
 
+#ifdef Quotient_E2EE_ENABLED
+    QSet<QString> trackedUsers;
+    QSet<QString> outdatedUsers;
+    QHash<QString, QHash<QString, QueryKeysJob::DeviceInformation>> deviceKeys;
+    QueryKeysJob *currentQueryKeysJob = nullptr;
+#endif
+
     GetCapabilitiesJob* capabilitiesJob = nullptr;
     GetCapabilitiesJob::Capabilities capabilities;
 
@@ -153,6 +160,7 @@ public:
     void consumeAccountData(Events&& accountDataEvents);
     void consumePresenceData(Events&& presenceData);
     void consumeToDeviceEvents(Events&& toDeviceEvents);
+    void consumeDevicesList(DevicesList&& devicesList);
 
     template <typename EventT>
     EventT* unpackAccountData() const
@@ -247,6 +255,10 @@ public:
         return std::move(decryptedEvent);
 #endif // Quotient_E2EE_ENABLED
     }
+#ifdef Quotient_E2EE_ENABLED
+    void loadOutdatedUserDevices();
+    void createDevicesList();
+#endif
 };
 
 Connection::Connection(const QUrl& server, QObject* parent)
@@ -468,6 +480,11 @@ void Connection::Private::completeSetup(const QString& mxId)
     emit q->stateChanged();
     emit q->connected();
     q->reloadCapabilities();
+#ifdef Quotient_E2EE_ENABLED
+    connectSingleShot(q, &Connection::syncDone, q, [=](){
+        createDevicesList();
+    });
+#endif
 }
 
 void Connection::Private::checkAndConnect(const QString& userId,
@@ -637,6 +654,7 @@ void Connection::onSyncSuccess(SyncData&& data, bool fromCache)
         });
     }
 #endif // Quotient_E2EE_ENABLED
+    d->consumeDevicesList(data.takeDevicesList());
 }
 
 void Connection::Private::consumeRoomData(SyncDataList&& roomDataList,
@@ -790,6 +808,21 @@ void Connection::Private::consumeToDeviceEvents(Events&& toDeviceEvents)
 #endif
 }
 
+void Connection::Private::consumeDevicesList(DevicesList&& devicesList)
+{
+#ifdef Quotient_E2EE_ENABLED
+    for(const auto &changed : devicesList.changed) {
+        outdatedUsers += changed;
+    }
+    for(const auto &left : devicesList.left) {
+        trackedUsers -= left;
+        outdatedUsers -= left;
+        deviceKeys.remove(left);
+    }
+    loadOutdatedUserDevices();
+#endif
+}
+
 void Connection::stopSync()
 {
     // If there's a sync loop, break it
@@ -1784,3 +1817,43 @@ QVector<Connection::SupportedRoomVersion> Connection::availableRoomVersions() co
     }
     return result;
 }
+
+#ifdef Quotient_E2EE_ENABLED
+void Connection::Private::createDevicesList()
+{
+    for(const auto &room : q->allRooms()) {
+        if(!room->usesEncryption()) {
+            continue;
+        }
+        for(const auto &user : room->users()) {
+            if(user->id() != q->userId()) {
+                trackedUsers += user->id();
+            }
+        }
+    }
+    outdatedUsers += trackedUsers;
+    loadOutdatedUserDevices();
+}
+
+void Connection::Private::loadOutdatedUserDevices()
+{
+    QHash<QString, QStringList> users;
+    for(const auto &user : outdatedUsers) {
+        users[user] += QStringList();
+    }
+    if(currentQueryKeysJob) {
+        currentQueryKeysJob->abandon();
+        currentQueryKeysJob = nullptr;
+    }
+    auto queryKeysJob = q->callApi<QueryKeysJob>(users);
+    currentQueryKeysJob = queryKeysJob;
+    connect(queryKeysJob, &BaseJob::success, q, [=](){
+        const auto data = queryKeysJob->deviceKeys();
+        for(const auto &[user, keys] : asKeyValueRange(data)) {
+            //TODO Check key signature
+            deviceKeys[user] = keys;
+            outdatedUsers -= user;
+        }
+    });
+}
+#endif
diff --git a/lib/syncdata.cpp b/lib/syncdata.cpp
index 396e77eb..9c54888c 100644
--- a/lib/syncdata.cpp
+++ b/lib/syncdata.cpp
@@ -99,6 +99,34 @@ SyncRoomData::SyncRoomData(QString roomId_, JoinState joinState,
     fromJson(unreadJson.value(HighlightCountKey), highlightCount);
 }
 
+QDebug Quotient::operator<<(QDebug dbg, const DevicesList& devicesList)
+{
+    QDebugStateSaver _(dbg);
+    QStringList sl;
+    if (!devicesList.changed.isEmpty())
+        sl << QStringLiteral("changed: %1").arg(devicesList.changed.join(", "));
+    if (!devicesList.left.isEmpty())
+        sl << QStringLiteral("left %1").arg(devicesList.left.join(", "));
+    dbg.nospace().noquote() << sl.join(QStringLiteral("; "));
+    return dbg;
+}
+
+void JsonObjectConverter<DevicesList>::dumpTo(QJsonObject& jo,
+                                              const DevicesList& rs)
+{
+    addParam<IfNotEmpty>(jo, QStringLiteral("changed"),
+                         rs.changed);
+    addParam<IfNotEmpty>(jo, QStringLiteral("left"),
+                         rs.left);
+}
+
+void JsonObjectConverter<DevicesList>::fillFrom(const QJsonObject& jo,
+                                                DevicesList& rs)
+{
+    fromJson(jo["changed"_ls], rs.changed);
+    fromJson(jo["left"_ls], rs.left);
+}
+
 SyncData::SyncData(const QString& cacheFileName)
 {
     QFileInfo cacheFileInfo { cacheFileName };
@@ -133,6 +161,8 @@ std::pair<int, int> SyncData::cacheVersion()
     return { MajorCacheVersion, 2 };
 }
 
+DevicesList&& SyncData::takeDevicesList() { return std::move(devicesList); }
+
 QJsonObject SyncData::loadJson(const QString& fileName)
 {
     QFile roomFile { fileName };
diff --git a/lib/syncdata.h b/lib/syncdata.h
index 36d2e0bf..7fa77eda 100644
--- a/lib/syncdata.h
+++ b/lib/syncdata.h
@@ -41,6 +41,27 @@ struct JsonObjectConverter<RoomSummary> {
     static void fillFrom(const QJsonObject& jo, RoomSummary& rs);
 };
 
+/// Information on e2e device updates. Note: only present on an
+/// incremental sync.
+struct DevicesList {
+    /// List of users who have updated their device identity keys, or who
+    /// now share an encrypted room with the client since the previous
+    /// sync response.
+    QStringList changed;
+
+    /// List of users with whom we do not share any encrypted rooms
+    /// anymore since the previous sync response.
+    QStringList left;
+};
+
+QDebug operator<<(QDebug dhg, const DevicesList &devicesList);
+
+template <>
+struct JsonObjectConverter<DevicesList> {
+    static void dumpTo(QJsonObject &jo, const DevicesList &dev);
+    static void fillFrom(const QJsonObject& jo, DevicesList& rs);
+};
+
 class SyncRoomData {
 public:
     QString roomId;
@@ -85,6 +106,7 @@ public:
         return deviceOneTimeKeysCount_;
     }
     SyncDataList&& takeRoomData();
+    DevicesList&& takeDevicesList();
 
     QString nextBatch() const { return nextBatch_; }
 
@@ -102,6 +124,7 @@ private:
     SyncDataList roomData;
     QStringList unresolvedRoomIds;
     QHash<QString, int> deviceOneTimeKeysCount_;
+    DevicesList devicesList;
 
     static QJsonObject loadJson(const QString& fileName);
 };
-- 
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