Refactor toJson/fillJson

Both now use through a common JsonConverter<> template class with its
base definition tuned for structs/QJsonObjects and specialisations for
non-object types. This new implementation doesn't work with virtual
fillJson functions yet (so EventContent classes still use toJson as a
member function) and does not cope quite well with non-constructible
objects (you have to specialise JsonConverter<> rather than, more
intuitively, JsonObjectConverter<>), but overall is more streamlined
compared to the previous implementation. It also fixes one important
issue that pushed for a rewrite: the previous implementation was not
working with structure hierarchies at all so (in particular) the Filter
part of CS API was totally disfunctional.

6 files changed, 31 insertions, 56 deletions

diff --git a/lib/identity/definitions/request_email_validation.cpp b/lib/identity/definitions/request_email_validation.cpp
index 95088bcb..47463a8b 100644
--- a/lib/identity/definitions/request_email_validation.cpp
+++ b/lib/identity/definitions/request_email_validation.cpp
@@ -6,28 +6,21 @@
 
 using namespace QMatrixClient;
 
-QJsonObject QMatrixClient::toJson(const RequestEmailValidation& pod)
+void JsonObjectConverter<RequestEmailValidation>::dumpTo(
+        QJsonObject& jo, const RequestEmailValidation& pod)
 {
-    QJsonObject jo;
     addParam<>(jo, QStringLiteral("client_secret"), pod.clientSecret);
     addParam<>(jo, QStringLiteral("email"), pod.email);
     addParam<>(jo, QStringLiteral("send_attempt"), pod.sendAttempt);
     addParam<IfNotEmpty>(jo, QStringLiteral("next_link"), pod.nextLink);
-    return jo;
 }
 
-RequestEmailValidation FromJsonObject<RequestEmailValidation>::operator()(const QJsonObject& jo) const
+void JsonObjectConverter<RequestEmailValidation>::fillFrom(
+    const QJsonObject& jo, RequestEmailValidation& result)
 {
-    RequestEmailValidation result;
-    result.clientSecret =
-        fromJson<QString>(jo.value("client_secret"_ls));
-    result.email =
-        fromJson<QString>(jo.value("email"_ls));
-    result.sendAttempt =
-        fromJson<int>(jo.value("send_attempt"_ls));
-    result.nextLink =
-        fromJson<QString>(jo.value("next_link"_ls));
-
-    return result;
+    fromJson(jo.value("client_secret"_ls), result.clientSecret);
+    fromJson(jo.value("email"_ls), result.email);
+    fromJson(jo.value("send_attempt"_ls), result.sendAttempt);
+    fromJson(jo.value("next_link"_ls), result.nextLink);
 }
 
diff --git a/lib/identity/definitions/request_email_validation.h b/lib/identity/definitions/request_email_validation.h
index 3e72275f..eb7d8ed6 100644
--- a/lib/identity/definitions/request_email_validation.h
+++ b/lib/identity/definitions/request_email_validation.h
@@ -33,12 +33,10 @@ namespace QMatrixClient
         /// server will redirect the user to this URL.
         QString nextLink;
     };
-
-    QJsonObject toJson(const RequestEmailValidation& pod);
-
-    template <> struct FromJsonObject<RequestEmailValidation>
+    template <> struct JsonObjectConverter<RequestEmailValidation>
     {
-        RequestEmailValidation operator()(const QJsonObject& jo) const;
+        static void dumpTo(QJsonObject& jo, const RequestEmailValidation& pod);
+        static void fillFrom(const QJsonObject& jo, RequestEmailValidation& pod);
     };
 
 } // namespace QMatrixClient
diff --git a/lib/identity/definitions/request_msisdn_validation.cpp b/lib/identity/definitions/request_msisdn_validation.cpp
index 125baa9c..a123d326 100644
--- a/lib/identity/definitions/request_msisdn_validation.cpp
+++ b/lib/identity/definitions/request_msisdn_validation.cpp
@@ -6,31 +6,23 @@
 
 using namespace QMatrixClient;
 
-QJsonObject QMatrixClient::toJson(const RequestMsisdnValidation& pod)
+void JsonObjectConverter<RequestMsisdnValidation>::dumpTo(
+        QJsonObject& jo, const RequestMsisdnValidation& pod)
 {
-    QJsonObject jo;
     addParam<>(jo, QStringLiteral("client_secret"), pod.clientSecret);
     addParam<>(jo, QStringLiteral("country"), pod.country);
     addParam<>(jo, QStringLiteral("phone_number"), pod.phoneNumber);
     addParam<>(jo, QStringLiteral("send_attempt"), pod.sendAttempt);
     addParam<IfNotEmpty>(jo, QStringLiteral("next_link"), pod.nextLink);
-    return jo;
 }
 
-RequestMsisdnValidation FromJsonObject<RequestMsisdnValidation>::operator()(const QJsonObject& jo) const
+void JsonObjectConverter<RequestMsisdnValidation>::fillFrom(
+    const QJsonObject& jo, RequestMsisdnValidation& result)
 {
-    RequestMsisdnValidation result;
-    result.clientSecret =
-        fromJson<QString>(jo.value("client_secret"_ls));
-    result.country =
-        fromJson<QString>(jo.value("country"_ls));
-    result.phoneNumber =
-        fromJson<QString>(jo.value("phone_number"_ls));
-    result.sendAttempt =
-        fromJson<int>(jo.value("send_attempt"_ls));
-    result.nextLink =
-        fromJson<QString>(jo.value("next_link"_ls));
-
-    return result;
+    fromJson(jo.value("client_secret"_ls), result.clientSecret);
+    fromJson(jo.value("country"_ls), result.country);
+    fromJson(jo.value("phone_number"_ls), result.phoneNumber);
+    fromJson(jo.value("send_attempt"_ls), result.sendAttempt);
+    fromJson(jo.value("next_link"_ls), result.nextLink);
 }
 
diff --git a/lib/identity/definitions/request_msisdn_validation.h b/lib/identity/definitions/request_msisdn_validation.h
index 77bea2bc..b48ed6d5 100644
--- a/lib/identity/definitions/request_msisdn_validation.h
+++ b/lib/identity/definitions/request_msisdn_validation.h
@@ -36,12 +36,10 @@ namespace QMatrixClient
         /// server will redirect the user to this URL.
         QString nextLink;
     };
-
-    QJsonObject toJson(const RequestMsisdnValidation& pod);
-
-    template <> struct FromJsonObject<RequestMsisdnValidation>
+    template <> struct JsonObjectConverter<RequestMsisdnValidation>
     {
-        RequestMsisdnValidation operator()(const QJsonObject& jo) const;
+        static void dumpTo(QJsonObject& jo, const RequestMsisdnValidation& pod);
+        static void fillFrom(const QJsonObject& jo, RequestMsisdnValidation& pod);
     };
 
 } // namespace QMatrixClient
diff --git a/lib/identity/definitions/sid.cpp b/lib/identity/definitions/sid.cpp
index 443dbedf..1ba4b3b5 100644
--- a/lib/identity/definitions/sid.cpp
+++ b/lib/identity/definitions/sid.cpp
@@ -6,19 +6,15 @@
 
 using namespace QMatrixClient;
 
-QJsonObject QMatrixClient::toJson(const Sid& pod)
+void JsonObjectConverter<Sid>::dumpTo(
+        QJsonObject& jo, const Sid& pod)
 {
-    QJsonObject jo;
     addParam<>(jo, QStringLiteral("sid"), pod.sid);
-    return jo;
 }
 
-Sid FromJsonObject<Sid>::operator()(const QJsonObject& jo) const
+void JsonObjectConverter<Sid>::fillFrom(
+    const QJsonObject& jo, Sid& result)
 {
-    Sid result;
-    result.sid =
-        fromJson<QString>(jo.value("sid"_ls));
-
-    return result;
+    fromJson(jo.value("sid"_ls), result.sid);
 }
 
diff --git a/lib/identity/definitions/sid.h b/lib/identity/definitions/sid.h
index eae60c47..ac8c4130 100644
--- a/lib/identity/definitions/sid.h
+++ b/lib/identity/definitions/sid.h
@@ -19,12 +19,10 @@ namespace QMatrixClient
         /// must not be empty.
         QString sid;
     };
-
-    QJsonObject toJson(const Sid& pod);
-
-    template <> struct FromJsonObject<Sid>
+    template <> struct JsonObjectConverter<Sid>
     {
-        Sid operator()(const QJsonObject& jo) const;
+        static void dumpTo(QJsonObject& jo, const Sid& pod);
+        static void fillFrom(const QJsonObject& jo, Sid& pod);
     };
 
 } // namespace QMatrixClient