Make ReceiptEvent constructible from content

Makes the Room::P::toJson() code more readable.

4 files changed, 40 insertions, 28 deletions

diff --git a/lib/converters.h b/lib/converters.h
index 2df18b03..d9a68bfb 100644
--- a/lib/converters.h
+++ b/lib/converters.h
@@ -134,7 +134,10 @@ struct JsonConverter<QString> : public TrivialJsonDumper<QString> {
 
 template <>
 struct JsonConverter<QDateTime> {
-    static auto dump(const QDateTime& val) = delete; // not provided yet
+    static auto dump(const QDateTime& val)
+    {
+        return val.isValid() ? val.toMSecsSinceEpoch() : QJsonValue();
+    }
     static auto load(const QJsonValue& jv)
     {
         return QDateTime::fromMSecsSinceEpoch(fromJson<qint64>(jv), Qt::UTC);
@@ -143,7 +146,7 @@ struct JsonConverter<QDateTime> {
 
 template <>
 struct JsonConverter<QDate> {
-    static auto dump(const QDate& val) = delete; // not provided yet
+    static auto dump(const QDate& val) { return toJson(QDateTime(val)); }
     static auto load(const QJsonValue& jv)
     {
         return fromJson<QDateTime>(jv).date();
diff --git a/lib/events/receiptevent.cpp b/lib/events/receiptevent.cpp
index 4185d92d..72dbf2e3 100644
--- a/lib/events/receiptevent.cpp
+++ b/lib/events/receiptevent.cpp
@@ -25,6 +25,27 @@ Example of a Receipt Event:
 
 using namespace Quotient;
 
+// The library loads the event-ids-to-receipts JSON map into a vector because
+// map lookups are not used and vectors are massively faster. Same goes for
+// de-/serialization of ReceiptsForEvent::receipts.
+// (XXX: would this be generally preferred across CS API JSON maps?..)
+QJsonObject toJson(const EventsWithReceipts& ewrs)
+{
+    QJsonObject json;
+    for (const auto& e : ewrs) {
+        QJsonObject receiptsJson;
+        for (const auto& r : e.receipts)
+            receiptsJson.insert(r.userId,
+                                QJsonObject { { "ts"_ls, toJson(r.timestamp) } });
+        json.insert(e.evtId, QJsonObject { { "m.read"_ls, receiptsJson } });
+    }
+    return json;
+}
+
+ReceiptEvent::ReceiptEvent(const EventsWithReceipts &ewrs)
+    : Event(typeId(), matrixTypeId(), toJson(ewrs))
+{}
+
 EventsWithReceipts ReceiptEvent::eventsWithReceipts() const
 {
     EventsWithReceipts result;
@@ -39,14 +60,14 @@ EventsWithReceipts ReceiptEvent::eventsWithReceipts() const
         }
         const auto reads =
             eventIt.value().toObject().value("m.read"_ls).toObject();
-        QVector<Receipt> receipts;
-        receipts.reserve(reads.size());
+        QVector<UserTimestamp> usersAtEvent;
+        usersAtEvent.reserve(reads.size());
         for (auto userIt = reads.begin(); userIt != reads.end(); ++userIt) {
             const auto user = userIt.value().toObject();
-            receipts.push_back(
+            usersAtEvent.push_back(
                 { userIt.key(), fromJson<QDateTime>(user["ts"_ls]) });
         }
-        result.push_back({ eventIt.key(), std::move(receipts) });
+        result.push_back({ eventIt.key(), std::move(usersAtEvent) });
     }
     return result;
 }
diff --git a/lib/events/receiptevent.h b/lib/events/receiptevent.h
index 4feec9ea..9683deef 100644
--- a/lib/events/receiptevent.h
+++ b/lib/events/receiptevent.h
@@ -9,19 +9,20 @@
 #include <QtCore/QVector>
 
 namespace Quotient {
-struct Receipt {
+struct UserTimestamp {
     QString userId;
     QDateTime timestamp;
 };
 struct ReceiptsForEvent {
     QString evtId;
-    QVector<Receipt> receipts;
+    QVector<UserTimestamp> receipts;
 };
 using EventsWithReceipts = QVector<ReceiptsForEvent>;
 
 class ReceiptEvent : public Event {
 public:
     DEFINE_EVENT_TYPEID("m.receipt", ReceiptEvent)
+    explicit ReceiptEvent(const EventsWithReceipts& ewrs);
     explicit ReceiptEvent(const QJsonObject& obj) : Event(typeId(), obj) {}
 
     EventsWithReceipts eventsWithReceipts() const;
diff --git a/lib/room.cpp b/lib/room.cpp
index 4d11878f..58950aac 100644
--- a/lib/room.cpp
+++ b/lib/room.cpp
@@ -2813,7 +2813,7 @@ Room::Changes Room::processEphemeralEvent(EventPtr&& event)
             // are not supposed to move backwards. Otherwise, blindly store
             // the event id for this user and update the read marker when/if
             // the event is fetched later on.
-            for (const Receipt& r : p.receipts)
+            for (const auto& r : p.receipts)
                 if (isMember(r.userId)) {
                     d->setLastReadReceipt(user(r.userId), newMarker,
                                           { p.evtId, r.timestamp });
@@ -3021,30 +3021,17 @@ QJsonObject Room::Private::toJson() const
                           { QStringLiteral("events"), accountDataEvents } });
     }
 
-    if (const auto& readReceiptEventId =
-            lastReadReceipts.value(q->localUser()).eventId;
-        !readReceiptEventId.isEmpty()) //
+    if (const auto& readReceipt = q->lastReadReceipt(connection->userId());
+        !readReceipt.eventId.isEmpty()) //
     {
-        // Okay, that's a mouthful; but basically, it's simply placing an m.read
-        // event in the 'ephemeral' section of the cached sync payload.
-        // See also receiptevent.* and m.read example in the spec.
-        // Only the local user's read receipt is saved - others' are really
-        // considered ephemeral but this one is useful in understanding where
-        // the user is in the timeline before any history is loaded.
         result.insert(
             QStringLiteral("ephemeral"),
             QJsonObject {
                 { QStringLiteral("events"),
-                  QJsonArray { QJsonObject {
-                      { TypeKey, ReceiptEvent::matrixTypeId() },
-                      { ContentKey,
-                        QJsonObject {
-                            { readReceiptEventId,
-                              QJsonObject {
-                                  { QStringLiteral("m.read"),
-                                    QJsonObject {
-                                        { connection->userId(),
-                                          QJsonObject {} } } } } } } } } } } });
+                  QJsonArray { ReceiptEvent({ { readReceipt.eventId,
+                                                { { connection->userId(),
+                                                    readReceipt.timestamp } } } })
+                                   .fullJson() } } });
     }
 
     QJsonObject unreadNotifObj { { SyncRoomData::UnreadCountKey,