Add subscription recovery for http2 channel

- Add subscription recovery mechanism integrated into Http2 channel
- Coding style improvements
- Supress warning about packet size in case if all data is read in
  Http2 channel
- Qt >= 5.12.5/5.14 required for subscription recovery and works only
  with secured channels
- Supress suspicious issue in chat server. Seems there is issue in HPACK
  decoder in reference C++ GRPC
TODO: Fixes for Http2 still required from Qt side, error handling is
      not working as expected so far

examples/simplechatserver/main.cpp

@@ -70,6 +70,7 @@ public:
             }
             if ((*it).first == std::string("user-password")) {
                 password = std::string((*it).second.data());
+                password.resize(32);
             }
         }
         return std::make_tuple(name, password);

src/grpc/qgrpchttp2channel.cpp

@@ -41,6 +41,8 @@
 #include "qprotobufserializerregistry_p.h"
 #include "qtprotobuflogging.h"
 
+#include <qglobal.h>
+
 using namespace QtProtobuf;
 
 namespace  {
@@ -89,7 +91,7 @@ const char *AcceptEncodingHeader = "accept-encoding";
 const char *TEHeader = "te";
 const char *GrpcStatusHeader = "grpc-status";
 const char *GrpcStatusMessage = "grpc-message";
-const int GRpcMessageSizeHeaderSize = 5;
+const int GrpcMessageSizeHeaderSize = 5;
 }
 
 namespace QtProtobuf {
@@ -124,7 +126,7 @@ struct QGrpcHttp2ChannelPrivate {
 
         request.setAttribute(QNetworkRequest::Http2DirectAttribute, true);
 
-        QByteArray msg(GRpcMessageSizeHeaderSize, '\0');
+        QByteArray msg(GrpcMessageSizeHeaderSize, '\0');
         *(int *)(msg.data() + 1) = qToBigEndian(args.size());
         msg += args;
         qProtoDebug() << "SEND: " << msg.size();
@@ -167,7 +169,7 @@ struct QGrpcHttp2ChannelPrivate {
         }
 
         //Message size doesn't matter for now
-        return networkReply->readAll().mid(GRpcMessageSizeHeaderSize);
+        return networkReply->readAll().mid(GrpcMessageSizeHeaderSize);
     }
 
     QGrpcHttp2ChannelPrivate(const QUrl &_url, const AbstractCredentials &_credentials)
@@ -185,7 +187,7 @@ struct QGrpcHttp2ChannelPrivate {
     }
 
     static int getExpectedDataSize(const QByteArray &container) {
-        return qFromBigEndian(*(int *)(container.data() + 1)) + GRpcMessageSizeHeaderSize;
+        return qFromBigEndian(*(int *)(container.data() + 1)) + GrpcMessageSizeHeaderSize;
     }
 
     QObject lambdaContext;
@@ -275,16 +277,16 @@ void QGrpcHttp2Channel::subscribe(const QString &method, const QString &service,
         qProtoDebug() << "Proceed chunk: " << data.size() << " dataContainer: " << dataContainer.container.size() << " capacity: " << dataContainer.expectedSize;
         while (dataContainer.container.size() >= dataContainer.expectedSize) {
             qProtoDebug() << "Full data received: " << data.size() << " dataContainer: " << dataContainer.container.size() << " capacity: " << dataContainer.expectedSize;
-            handler(dataContainer.container.mid(GRpcMessageSizeHeaderSize, dataContainer.expectedSize - GRpcMessageSizeHeaderSize));
+            handler(dataContainer.container.mid(GrpcMessageSizeHeaderSize, dataContainer.expectedSize - GrpcMessageSizeHeaderSize));
             dataContainer.container.remove(0, dataContainer.expectedSize);
-            if (dataContainer.container.size() > GRpcMessageSizeHeaderSize) {
+            if (dataContainer.container.size() > GrpcMessageSizeHeaderSize) {
                 dataContainer.expectedSize = QGrpcHttp2ChannelPrivate::getExpectedDataSize(dataContainer.container);
-            } else {
+            } else if (dataContainer.container.size() > 0) {
                 qProtoWarning() << "Invalid container size received, size header is less than 5 bytes";
             }
         }
 
-        if (dataContainer.container.size() < GRpcMessageSizeHeaderSize) {
+        if (dataContainer.container.size() < GrpcMessageSizeHeaderSize) {
             d_ptr->activeStreamReplies.erase(replyIt);
         }
     });
@@ -295,11 +297,26 @@ void QGrpcHttp2Channel::subscribe(const QString &method, const QString &service,
         QGrpcHttp2ChannelPrivate::abortNetworkReply(networkReply);
     });
 
-    QObject::connect(networkReply, &QNetworkReply::finished, &(d_ptr->lambdaContext), [networkReply, connection, this]() {
+    QObject::connect(networkReply, &QNetworkReply::finished, &(d_ptr->lambdaContext), [method, service, args, client, handler, networkReply, connection, this]() {
+        QString errorString = networkReply->errorString();
+        QNetworkReply::NetworkError networkError = networkReply->error();
+
         d_ptr->activeStreamReplies.erase(networkReply);
-        //TODO: implement error handling and subscription recovery here
         QObject::disconnect(connection);
         QGrpcHttp2ChannelPrivate::abortNetworkReply(networkReply);
+
+        qProtoWarning() << method << "call" << service << "subscription finished: " << errorString;
+        switch(networkError) {
+        case QNetworkReply::RemoteHostClosedError:
+            subscribe(method, service, args, client, handler);
+            break;
+        case QNetworkReply::NoError:
+            break;
+        default:
+            client->error(QGrpcStatus{StatusCodeMap.at(networkError), QString("%1 call %2 subscription failed: %3").arg(service).arg(method).arg(errorString)});
+            subscribe(method, service, args, client, handler);
+            break;
+        }
     });
 }