Hi, I have a proposal to drastically reduce this kind of boilerplate code which I call "QBind". When I presented it last year to QtCS it was not mature enough but it know exhibits very good performance and convenience for this kind of use case.
Maybe you can have a look at QBind benchmark's main.cpp to see if the approach can suit your need : https://gricad-gitlab.univ-grenoble-alpes.fr/modmed/modmedLog/blob/master/tests/QBind/main.cpp #L67 defines a struct Person with internal bind method (it can be external too) >From them on, you can Read/Write a Person in various ways in a single line of >code: #L431 to QVariant container #L436 to Cbor buffer (3x faster) #L581 from Cbor buffer (with read errors) #L693 to QTreeView or QTableView using a QStandardItemModel and providing some metadata https://gricad-gitlab.univ-grenoble-alpes.fr/modmed/modmedLog/blob/master/tests/QBind/qstandardmodel.PNG Using QVariant as an intermediate data structure is not optimal to read/write your QList<MyStruct>: - dynamic allocations will significantly limit the write performance, see my benchmark that writes various tracepoint payloads to a QVariant container vs Cbor and Json buffers https://gricad-gitlab.univ-grenoble-alpes.fr/modmed/modmedLog/blob/master/tests/QBind/write.PNG - it also prevents from directly using the QList<MyStruct> type to guide the deserialization. In QBind you do not need to register types at runtime and you avoid losing data silently (instead you have static_asserts complaining at compile time). Arnaud Clère ________________________________ From: Vasily Pupkin <shkodindanil.letmew...@gmail.com> Sent: 01 April 2019 15:44 To: Thiago Macieira Cc: development@qt-project.org Subject: Re: [Development] QVariant container API > By the way, conversions through QVariant are *exactly* what I implemented in > the examples/corelib/serialization/convert tool. Right, I've seen these to be helpful. The global task would allow to code like this. ~ struct MyStruct { int property1; QString property2; }; class MyObject { Q_OBJECT ... public slots: void mySlot(const QList<MyStruct>& value); } QJsonDocument doc(...); QMetaMethod mySlot(...); JsonDeserializer deserializer; QVariant parameter; if(deserializer.deserialize(doc, mySlot.paremeterType(0), parameter) invoke(...); else { //error } ~ The only difference from examples, is that library user specifies, what datatype should be produced. This would alllow to significantly reduce the amount of boilerplate code.
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