Add version field to JSON messages on the host

This allows proper errors if mismatching versions of client and
hostserver are running.

Change-Id: I4b13e52d6b410cedc8a2a99ae94be77082b113da
Reviewed-by: Samuli Piippo <samuli.piippo@qt.io>

4 files changed, 150 insertions, 101 deletions

diff --git a/qdb/hostmessages.cpp b/qdb/hostmessages.cpp
new file mode 100644
index 0000000..9fda389
--- /dev/null
+++ b/qdb/hostmessages.cpp
@@ -0,0 +1,124 @@
+/******************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the Qt Debug Bridge.
+**
+** $QT_BEGIN_LICENSE:COMM$
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** $QT_END_LICENSE$
+**
+******************************************************************************/
+#include "hostmessages.h"
+
+const QString responseField = "response";
+const QString requestField = "request";
+const QString versionField = "_version";
+
+void setVersionField(QJsonObject &obj)
+{
+    obj[versionField] = qdbHostMessageVersion;
+}
+
+bool checkHostMessageVersion(const QJsonObject &obj)
+{
+    return obj[versionField].toInt() == qdbHostMessageVersion;
+}
+
+QByteArray createRequest(const RequestType &type)
+{
+    QJsonObject obj;
+    setVersionField(obj);
+    obj[requestField] = requestTypeString(type);
+    return QJsonDocument{obj}.toJson(QJsonDocument::Compact).append('\n');
+}
+
+RequestType requestType(const QJsonObject &obj)
+{
+    const auto fieldValue = obj[requestField];
+    if (fieldValue == requestTypeString(RequestType::Devices))
+        return RequestType::Devices;
+    if (fieldValue == requestTypeString(RequestType::WatchDevices))
+        return RequestType::WatchDevices;
+    if (fieldValue == requestTypeString(RequestType::StopServer))
+        return RequestType::StopServer;
+
+    return RequestType::Unknown;
+}
+
+QString requestTypeString(const RequestType &type)
+{
+    switch (type) {
+    case RequestType::Devices:
+        return "devices";
+    case RequestType::WatchDevices:
+        return "watch-devices";
+    case RequestType::StopServer:
+        return "stop-server";
+    case RequestType::Unknown:
+        break;
+    }
+    qFatal("Tried to use unknown request type as a value in requestTypeString");
+}
+
+QJsonObject initializeResponse(const ResponseType &type)
+{
+    QJsonObject obj;
+    setVersionField(obj);
+    obj[responseField] = responseTypeString(type);
+    return obj;
+}
+
+ResponseType responseType(const QJsonObject &obj)
+{
+    const auto fieldValue = obj[responseField];
+    if (fieldValue == responseTypeString(ResponseType::Devices))
+        return ResponseType::Devices;
+    if (fieldValue == responseTypeString(ResponseType::NewDevice))
+        return ResponseType::NewDevice;
+    if (fieldValue == responseTypeString(ResponseType::DisconnectedDevice))
+        return ResponseType::DisconnectedDevice;
+    if (fieldValue == responseTypeString(ResponseType::Stopping))
+        return ResponseType::Stopping;
+    if (fieldValue == responseTypeString(ResponseType::InvalidRequest))
+        return ResponseType::InvalidRequest;
+    if (fieldValue == responseTypeString(ResponseType::UnsupportedVersion))
+        return ResponseType::UnsupportedVersion;
+
+    return ResponseType::Unknown;
+}
+
+QString responseTypeString(const ResponseType &type)
+{
+    switch (type) {
+    case ResponseType::Devices:
+        return "devices";
+    case ResponseType::NewDevice:
+        return "new-device";
+    case ResponseType::DisconnectedDevice:
+        return "disconnected-device";
+    case ResponseType::Stopping:
+        return "stopping";
+    case ResponseType::InvalidRequest:
+        return "invalid-request";
+    case ResponseType::UnsupportedVersion:
+        return "unsupported-version";
+    case ResponseType::Unknown:
+        break;
+    }
+    qFatal("Tried to use unknown response type as a value in responseTypeString");
+}
+
+QByteArray serialiseResponse(const QJsonObject &obj)
+{
+    return QJsonDocument{obj}.toJson(QJsonDocument::Compact).append('\n');
+}
diff --git a/qdb/hostmessages.h b/qdb/hostmessages.h
index daf4620..beb6c3e 100644
--- a/qdb/hostmessages.h
+++ b/qdb/hostmessages.h
@@ -25,122 +25,35 @@
 #include <QtCore/qjsondocument.h>
 #include <QtCore/qjsonobject.h>
 
+const int qdbHostMessageVersion = 1;
+bool checkHostMessageVersion(const QJsonObject &obj);
+
 enum class RequestType
 {
+    Unknown = 0,
     Devices,
     WatchDevices,
     StopServer,
-    Unknown
 };
 
+QByteArray createRequest(const RequestType &type);
+RequestType requestType(const QJsonObject &obj);
+QString requestTypeString(const RequestType &type);
+
 enum class ResponseType
 {
+    Unknown = 0,
     Devices,
     NewDevice,
     DisconnectedDevice,
     Stopping,
     InvalidRequest,
-    Unknown
+    UnsupportedVersion,
 };
 
-inline
-QString responseTypeString(const ResponseType &type)
-{
-    const QString devicesValue = "devices";
-    const QString newDeviceValue = "new-device";
-    const QString disconnectedDeviceValue = "disconnected-device";
-    const QString stoppingValue = "stopping";
-    const QString invalidRequestValue = "invalid-request";
-
-    switch (type) {
-    case ResponseType::Devices:
-        return devicesValue;
-    case ResponseType::NewDevice:
-        return newDeviceValue;
-    case ResponseType::DisconnectedDevice:
-        return disconnectedDeviceValue;
-    case ResponseType::Stopping:
-        return stoppingValue;
-    case ResponseType::InvalidRequest:
-        return invalidRequestValue;
-    case ResponseType::Unknown:
-        break;
-    }
-    qFatal("Tried to use unknown response type as a value in responseTypeString");
-}
-
-inline
-QString requestTypeString(const RequestType &type)
-{
-    const QString devicesValue = "devices";
-    const QString watchDevicesValue = "watch-devices";
-    const QString stopServerValue = "stop-server";
-
-    switch (type) {
-    case RequestType::Devices:
-        return devicesValue;
-    case RequestType::WatchDevices:
-        return watchDevicesValue;
-    case RequestType::StopServer:
-        return stopServerValue;
-    case RequestType::Unknown:
-        break;
-    }
-    qFatal("Tried to use unknown request type as a value in requestTypeString");
-}
-
-inline
-ResponseType responseType(const QJsonObject &obj)
-{
-    const auto fieldValue = obj["response"];
-    if (fieldValue == responseTypeString(ResponseType::Devices))
-        return ResponseType::Devices;
-    if (fieldValue == responseTypeString(ResponseType::NewDevice))
-        return ResponseType::NewDevice;
-    if (fieldValue == responseTypeString(ResponseType::DisconnectedDevice))
-        return ResponseType::DisconnectedDevice;
-    if (fieldValue == responseTypeString(ResponseType::Stopping))
-        return ResponseType::Stopping;
-    if (fieldValue == responseTypeString(ResponseType::InvalidRequest))
-        return ResponseType::InvalidRequest;
-
-    return ResponseType::Unknown;
-}
-
-inline
-RequestType requestType(const QJsonObject &obj)
-{
-    const auto fieldValue = obj["request"];
-    if (fieldValue == requestTypeString(RequestType::Devices))
-        return RequestType::Devices;
-    if (fieldValue == requestTypeString(RequestType::WatchDevices))
-        return RequestType::WatchDevices;
-    if (fieldValue == requestTypeString(RequestType::StopServer))
-        return RequestType::StopServer;
-
-    return RequestType::Unknown;
-}
-
-inline
-QByteArray createRequest(const RequestType &type)
-{
-    QJsonObject obj;
-    obj["request"] = requestTypeString(type);
-    return QJsonDocument{obj}.toJson(QJsonDocument::Compact).append('\n');
-}
-
-inline
-QJsonObject initializeResponse(const ResponseType &type)
-{
-    QJsonObject obj;
-    obj["response"] = responseTypeString(type);
-    return obj;
-}
-
-inline
-QByteArray serialiseResponse(const QJsonObject &obj)
-{
-    return QJsonDocument{obj}.toJson(QJsonDocument::Compact).append('\n');
-}
+QJsonObject initializeResponse(const ResponseType &type);
+ResponseType responseType(const QJsonObject &obj);
+QString responseTypeString(const ResponseType &type);
+QByteArray serialiseResponse(const QJsonObject &obj);
 
 #endif // HOSTMESSAGES_H
diff --git a/qdb/qdb.pro b/qdb/qdb.pro
index 20ba110..efbc9a5 100644
--- a/qdb/qdb.pro
+++ b/qdb/qdb.pro
@@ -40,6 +40,7 @@ HEADERS += \
 
 SOURCES += \
     client/client.cpp \
+    hostmessages.cpp \
     main.cpp \
     server/connection.cpp \
     server/deviceinformationfetcher.cpp \
diff --git a/qdb/server/hostservlet.cpp b/qdb/server/hostservlet.cpp
index ac9f86e..d173919 100644
--- a/qdb/server/hostservlet.cpp
+++ b/qdb/server/hostservlet.cpp
@@ -80,6 +80,17 @@ void HostServlet::handleRequest()
     const auto request = QJsonDocument::fromJson(requestBytes);
     const auto type = requestType(request.object());
 
+    // Skip version check for requests to stop the server, to allow mismatching
+    // client to still stop the server
+    if (!checkHostMessageVersion(request.object()) && type != RequestType::StopServer) {
+        qCWarning(hostServerC) << "Request from client" << m_id << "was of an unsupported version";
+        QJsonObject response = initializeResponse(ResponseType::UnsupportedVersion);
+        response["supported-version"] = qdbHostMessageVersion;
+        m_socket->write(serialiseResponse(response));
+        close();
+        return;
+    }
+
     switch (type) {
     case RequestType::Devices:
         replyDevices();