Extend interface of gRPC operation with methods supporting QProtobufMessage

Add the following methods:
 - QGrpcOperation::read(QProtobufMessage *message) const
 - QGrpcClientStream::sendMessage(const QProtobufMessage *message)
 - QGrpcBidirStream::sendMessage(const QProtobufMessage *message)

Methods allow serializing/deserializing protobuf message using the
interface base class. These methods use the serializeRawMessage
and deserializeRawMessage methods of QAbstractProtobufSerializer, so
in current implentation they work relatively slower than their template
counterparts.

[ChangeLog][GRPC] Added the following interfaces to gRPC operation
classes:
 - QGrpcOperation::read(QProtobufMessage *message) const
 - QGrpcClientStream::sendMessage(const QProtobufMessage *message)
 - QGrpcBidirStream::sendMessage(const QProtobufMessage *message)

Task-number: QTBUG-120972
Change-Id: I6fb1ec20efd680cb45ccf13833cd5b712d2dd0aa
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>
Reviewed-by: Tatiana Borisova <tatiana.borisova@qt.io>

src/grpc/qgrpcoperation.cpp

@@ -109,6 +109,29 @@ QByteArray QGrpcOperation::data() const
     return d_func()->data;
 }
 
+/*!
+    \since 6.8
+    Reads a message from a raw byte array stored in QGrpcOperation.
+
+    The function writes a deserialized value to \a message pointer.
+
+    If deserialization is not successful the \l QGrpcOperation::errorOccurred
+    signal is emitted.
+
+    \note This function has slower message deserialization compared to its
+          template counterpart.
+
+*/
+void QGrpcOperation::read(QProtobufMessage *message) const
+{
+    Q_ASSERT_X(message != nullptr, "QGrpcOperation::read",
+               "Can't read to nullptr QProtobufMessage");
+    if (auto ser = serializer(); ser) {
+        if (!ser->deserializeRawMessage(message, data()))
+            emit errorOccurred(deserializationError());
+    }
+}
+
 /*!
     Getter of the metadata received from the channel. For the HTTP2 channels it
     usually contains the HTTP headers received from the server.

src/grpc/qgrpcoperation.h

@@ -31,6 +31,8 @@ public:
         return value;
     }
 
+    void read(QProtobufMessage *message) const;
+
     QGrpcMetadata metadata() const;
     QLatin1StringView method() const;
 

src/grpc/qgrpcstream.cpp

@@ -64,6 +64,18 @@ QGrpcClientStream::QGrpcClientStream(std::shared_ptr<QGrpcChannelOperation> chan
 */
 QGrpcClientStream::~QGrpcClientStream() = default;
 
+/*!
+    \since 6.8
+    Serializes \a message and sends it to the server.
+
+    \note This function has slower message serialization compared to its
+          template counterpart.
+*/
+void QGrpcClientStream::sendMessage(const QProtobufMessage *message)
+{
+    sendMessage(serializer()->serializeRawMessage(message));
+}
+
 /*!
     \internal
     Sends the serialized \a data to the server.
@@ -106,6 +118,18 @@ QGrpcBidirStream::QGrpcBidirStream(std::shared_ptr<QGrpcChannelOperation> channe
 */
 QGrpcBidirStream::~QGrpcBidirStream() = default;
 
+/*!
+    \since 6.8
+    Serializes \a message and sends it to the server.
+
+    \note This function has slower message serialization compared to its
+          template counterpart.
+*/
+void QGrpcBidirStream::sendMessage(const QProtobufMessage *message)
+{
+    sendMessage(serializer()->serializeRawMessage(message));
+}
+
 /*!
     \internal
     Sends the serialized \a data to the server.

src/grpc/qgrpcstream.h

@@ -41,6 +41,8 @@ public:
         sendMessage(serializer()->serialize<T>(&message));
     }
 
+    void sendMessage(const QProtobufMessage *message);
+
 private:
     void sendMessage(const QByteArray &data);
 };
@@ -59,6 +61,8 @@ public:
         sendMessage(serializer()->serialize<T>(&message));
     }
 
+    void sendMessage(const QProtobufMessage *message);
+
 Q_SIGNALS:
     void messageReceived();