Event content: provide toJson() instead of deriving from EC::Base

EventContent::Base has been made primarily for the sake of dynamic
polymorphism needed within RoomMessageEvent content (arguably, it might
not be really needed even there, but that's a bigger matter for another
time). When that polymorphism is not needed, it's easier for reading
and maintenance to have toJson() member function (or even specialise
JsonConverter<> outside of the content structure) instead of deriving
from EC::Base and then still having fillJson() member function. This
commit removes EventContent::Base dependency where it's not beneficial.

6 files changed, 19 insertions, 24 deletions

diff --git a/lib/events/encryptionevent.cpp b/lib/events/encryptionevent.cpp
index 47b0a032..6e994cd4 100644
--- a/lib/events/encryptionevent.cpp
+++ b/lib/events/encryptionevent.cpp
@@ -47,10 +47,12 @@ EncryptionEventContent::EncryptionEventContent(EncryptionType et)
     }
 }
 
-void EncryptionEventContent::fillJson(QJsonObject& o) const
+QJsonObject EncryptionEventContent::toJson() const
 {
+    QJsonObject o;
     if (encryption != EncryptionType::Undefined)
         o.insert(AlgorithmKey, algorithm);
     o.insert(RotationPeriodMsKey, rotationPeriodMs);
     o.insert(RotationPeriodMsgsKey, rotationPeriodMsgs);
+    return o;
 }
diff --git a/lib/events/encryptionevent.h b/lib/events/encryptionevent.h
index fe76b1af..5b5420ec 100644
--- a/lib/events/encryptionevent.h
+++ b/lib/events/encryptionevent.h
@@ -4,12 +4,11 @@
 
 #pragma once
 
-#include "eventcontent.h"
 #include "stateevent.h"
 #include "quotient_common.h"
 
 namespace Quotient {
-class QUOTIENT_API EncryptionEventContent : public EventContent::Base {
+class QUOTIENT_API EncryptionEventContent {
 public:
     enum EncryptionType : size_t { MegolmV1AesSha2 = 0, Undefined };
 
@@ -20,13 +19,12 @@ public:
     {}
     explicit EncryptionEventContent(const QJsonObject& json);
 
+    QJsonObject toJson() const;
+
     EncryptionType encryption;
     QString algorithm;
     int rotationPeriodMs;
     int rotationPeriodMsgs;
-
-protected:
-    void fillJson(QJsonObject& o) const override;
 };
 
 using EncryptionType = EncryptionEventContent::EncryptionType;
diff --git a/lib/events/roommemberevent.cpp b/lib/events/roommemberevent.cpp
index 55da5809..c3be0e00 100644
--- a/lib/events/roommemberevent.cpp
+++ b/lib/events/roommemberevent.cpp
@@ -4,8 +4,6 @@
 
 #include "roommemberevent.h"
 
-#include "logging.h"
-
 #include <QtCore/QtAlgorithms>
 
 namespace Quotient {
@@ -43,8 +41,9 @@ MemberEventContent::MemberEventContent(const QJsonObject& json)
         displayName = sanitized(*displayName);
 }
 
-void MemberEventContent::fillJson(QJsonObject& o) const
+QJsonObject MemberEventContent::toJson() const
 {
+    QJsonObject o;
     if (membership != Membership::Invalid)
         o.insert(QStringLiteral("membership"),
                   MembershipStrings[qCountTrailingZeroBits(
@@ -55,6 +54,7 @@ void MemberEventContent::fillJson(QJsonObject& o) const
         o.insert(QStringLiteral("avatar_url"), avatarUrl->toString());
     if (!reason.isEmpty())
         o.insert(QStringLiteral("reason"), reason);
+    return o;
 }
 
 bool RoomMemberEvent::changesMembership() const
diff --git a/lib/events/roommemberevent.h b/lib/events/roommemberevent.h
index afbaf825..dd33ea6b 100644
--- a/lib/events/roommemberevent.h
+++ b/lib/events/roommemberevent.h
@@ -5,18 +5,18 @@
 
 #pragma once
 
-#include "eventcontent.h"
 #include "stateevent.h"
 #include "quotient_common.h"
 
 namespace Quotient {
-class QUOTIENT_API MemberEventContent : public EventContent::Base {
+class QUOTIENT_API MemberEventContent {
 public:
     using MembershipType
         [[deprecated("Use Quotient::Membership instead")]] = Membership;
 
     QUO_IMPLICIT MemberEventContent(Membership ms) : membership(ms) {}
     explicit MemberEventContent(const QJsonObject& json);
+    QJsonObject toJson() const;
 
     Membership membership;
     /// (Only for invites) Whether the invite is to a direct chat
@@ -24,9 +24,6 @@ public:
     Omittable<QString> displayName;
     Omittable<QUrl> avatarUrl;
     QString reason;
-
-protected:
-    void fillJson(QJsonObject& o) const override;
 };
 
 using MembershipType [[deprecated("Use Membership instead")]] = Membership;
diff --git a/lib/events/roompowerlevelsevent.cpp b/lib/events/roompowerlevelsevent.cpp
index 1c87fd47..84a31d55 100644
--- a/lib/events/roompowerlevelsevent.cpp
+++ b/lib/events/roompowerlevelsevent.cpp
@@ -3,8 +3,6 @@
 
 #include "roompowerlevelsevent.h"
 
-#include <QJsonDocument>
-
 using namespace Quotient;
 
 PowerLevelsEventContent::PowerLevelsEventContent(const QJsonObject& json) :
@@ -21,7 +19,9 @@ PowerLevelsEventContent::PowerLevelsEventContent(const QJsonObject& json) :
 {
 }
 
-void PowerLevelsEventContent::fillJson(QJsonObject& o) const {
+QJsonObject PowerLevelsEventContent::toJson() const
+{
+    QJsonObject o;
     o.insert(QStringLiteral("invite"), invite);
     o.insert(QStringLiteral("kick"), kick);
     o.insert(QStringLiteral("ban"), ban);
@@ -31,7 +31,9 @@ void PowerLevelsEventContent::fillJson(QJsonObject& o) const {
     o.insert(QStringLiteral("state_default"), stateDefault);
     o.insert(QStringLiteral("users"), Quotient::toJson(users));
     o.insert(QStringLiteral("users_default"), usersDefault);
-    o.insert(QStringLiteral("notifications"), QJsonObject{{"room", notifications.room}});
+    o.insert(QStringLiteral("notifications"),
+             QJsonObject { { "room", notifications.room } });
+    return o;
 }
 
 int RoomPowerLevelsEvent::powerLevelForEvent(const QString &eventId) const {
diff --git a/lib/events/roompowerlevelsevent.h b/lib/events/roompowerlevelsevent.h
index 3ce83763..a1638a27 100644
--- a/lib/events/roompowerlevelsevent.h
+++ b/lib/events/roompowerlevelsevent.h
@@ -3,17 +3,16 @@
 
 #pragma once
 
-#include "eventcontent.h"
 #include "stateevent.h"
 
 namespace Quotient {
-class QUOTIENT_API PowerLevelsEventContent : public EventContent::Base {
-public:
+struct QUOTIENT_API PowerLevelsEventContent {
     struct Notifications {
         int room;
     };
 
     explicit PowerLevelsEventContent(const QJsonObject& json);
+    QJsonObject toJson() const;
 
     int invite;
     int kick;
@@ -29,9 +28,6 @@ public:
     int usersDefault;
 
     Notifications notifications;
-
-protected:
-    void fillJson(QJsonObject& o) const override;
 };
 
 class QUOTIENT_API RoomPowerLevelsEvent