refs #883, improved detection if core is running

* use proxy to really ping core (not only checking connection)
* avoid closing Qt default connections -> crash
* some refactoring

src/blackcore/context/contextapplicationproxy.cpp

@@ -9,10 +9,10 @@
 
 #include "blackcore/context/contextapplicationproxy.h"
 #include "blackmisc/dbus.h"
+#include "blackmisc/dbusserver.h"
 #include "blackmisc/genericdbusinterface.h"
 #include "blackmisc/identifierlist.h"
 #include "blackmisc/loghandler.h"
-#include "blackmisc/settingscache.h"
 
 #include <QDBusConnection>
 #include <QLatin1Literal>
@@ -20,6 +20,7 @@
 #include <QtGlobal>
 
 using namespace BlackMisc;
+
 namespace BlackCore
 {
     namespace Context
@@ -179,5 +180,28 @@ namespace BlackCore
             if (fileName.isEmpty()) { return false; }
             return this->m_dBusInterface->callDBusRet<bool>(QLatin1Literal("existsFile"), fileName);
         }
+
+        bool CContextApplicationProxy::isContextResponsive(const QString &dBusAddress, QString &msg, int timeoutMs)
+        {
+            const bool connected = CDBusServer::isDBusAvailable(dBusAddress, msg, timeoutMs);
+            if (!connected) { return false; }
+
+            static const QString dBusName("contexttest");
+            QDBusConnection connection = CDBusServer::connectToDBus(dBusAddress, dBusName);
+            CContextApplicationProxy proxy(BlackMisc::CDBusServer::coreServiceName(), connection, CCoreFacadeConfig::Remote, nullptr);
+            const CIdentifier id("swift proxy test");
+            const CIdentifier pingId = proxy.registerApplication(id);
+            const bool ok = (id == pingId);
+            if (ok)
+            {
+                proxy.unregisterApplication(id);
+            }
+            else
+            {
+                msg = "Mismatch in proxy ping, context not ready.";
+            }
+            CDBusServer::disconnectFromDBus(connection, dBusAddress);
+            return ok;
+        }
     } // namespace
 } // namespace

src/blackcore/context/contextapplicationproxy.h

@@ -74,6 +74,11 @@ namespace BlackCore
             virtual bool existsFile(const QString &fileName) const override;
             //! @}
 
+            //! Used to test if there is a core running?
+            //! \note creates and connects via proxy object, so not meant for very frequent tests
+            //! \sa CDBusServer::isDBusAvailable as lightweight, but less accurate alternative
+            static bool isContextResponsive(const QString &dbusAddress, QString &msg, int timeoutMs = 1500);
+
         protected:
             //! Constructor
             CContextApplicationProxy(CCoreFacadeConfig::ContextMode mode, CCoreFacade *runtime) : IContextApplication(mode, runtime), m_dBusInterface(nullptr) {}

src/blackmisc/dbusserver.cpp

@@ -36,7 +36,7 @@ namespace BlackMisc
                 testConnection.disconnectFromBus(coreServiceName());
 
                 // Sleep for 200 ms in order for dbus-daemon to finish loading.
-                // FIXME: Dirty workaround. Instead poll the the server up to x times every 50 ms until it connection is accepted.
+                // FIXME: Dirty workaround. Instead polling the server up to x times every 50 ms until its connection is accepted.
                 QThread::msleep(200);
 
                 QDBusConnection connection = QDBusConnection::connectToBus(QDBusConnection::SessionBus, coreServiceName());
@@ -122,7 +122,7 @@ namespace BlackMisc
         if (address.contains("host=") || address.contains("port="))
         {
             // "tcp:host=foo.com,port=123"
-            QStringList parts(address.split(','));
+            const QStringList parts(address.split(','));
             for (const QString &part : parts)
             {
                 if (part.startsWith("host="))
@@ -148,6 +148,12 @@ namespace BlackMisc
         }
     }
 
+    bool CDBusServer::isQtDefaultConnection(const QDBusConnection &connection)
+    {
+        return connection.name() == QDBusConnection::sessionBus().name() ||
+               connection.name() == QDBusConnection::systemBus().name();
+    }
+
     bool CDBusServer::isQtDBusAddress(const QString &address)
     {
         return address.startsWith("tcp:") || address.startsWith("unix:");
@@ -300,6 +306,39 @@ namespace BlackMisc
         return system;
     }
 
+    QDBusConnection CDBusServer::connectToDBus(const QString &dBusAddress, const QString &name)
+    {
+        if (dBusAddress == sessionBusAddress())
+        {
+            if (name.isEmpty()) return QDBusConnection::sessionBus();
+            return QDBusConnection::connectToBus(QDBusConnection::SessionBus, name);
+        }
+        else if (dBusAddress == systemBusAddress())
+        {
+            if (name.isEmpty()) return QDBusConnection::systemBus();
+            return QDBusConnection::connectToBus(QDBusConnection::SystemBus, name);
+        }
+        else if (isP2PAddress(dBusAddress))
+        {
+            return QDBusConnection::connectToPeer(dBusAddress,
+                                                  name.isEmpty() ? CDBusServer::p2pConnectionName() : name);
+        }
+        return QDBusConnection("invalid");
+    }
+
+    void CDBusServer::disconnectFromDBus(const QDBusConnection &connection, const QString &dBusAddress)
+    {
+        if (CDBusServer::isQtDefaultConnection(connection)) return; // do not touch the default connections
+        if (CDBusServer::isP2PAddress(dBusAddress))
+        {
+            QDBusConnection::disconnectFromPeer(connection.name());
+        }
+        else
+        {
+            QDBusConnection::disconnectFromBus(connection.name());
+        }
+    }
+
     QString CDBusServer::p2pAddress(const QString &host, const QString &port)
     {
         QString h = host.trimmed().toLower().remove(' ');
@@ -329,7 +368,7 @@ namespace BlackMisc
             // 192.168.5.3:9300 style
             if (h.contains(":"))
             {
-                QStringList parts = h.split(":");
+                const QStringList parts = h.split(":");
                 h = parts.at(0).trimmed();
                 p = parts.at(1).trimmed();
             }
@@ -344,6 +383,12 @@ namespace BlackMisc
         return QString("tcp:host=%1,port=%2").arg(h).arg(p);
     }
 
+    const QString &CDBusServer::p2pConnectionName()
+    {
+        static const QString n("p2pConnection");
+        return n;
+    }
+
     QString CDBusServer::normalizeAddress(const QString &address)
     {
         const QString lc(address.toLower().trimmed());
@@ -355,7 +400,7 @@ namespace BlackMisc
         if (lc.startsWith("sys")) { return systemBusAddress(); }
         if (lc.startsWith("ses")) { return sessionBusAddress(); }
 
-        // Qt / p2p
+        // Qt / P2P
         if (isQtDBusAddress(address)) { return address; }
         return p2pAddress(address);
     }
@@ -374,41 +419,28 @@ namespace BlackMisc
         return CNetworkUtils::canConnect(address, port, unused, timeoutMs);
     }
 
-    bool CDBusServer::isDBusAvailable(const QString &address, int port, QString &o_message, int timeoutMs)
+    bool CDBusServer::isDBusAvailable(const QString &address, int port, QString &message, int timeoutMs)
     {
-        return CNetworkUtils::canConnect(address, port, o_message, timeoutMs);
+        return CNetworkUtils::canConnect(address, port, message, timeoutMs);
     }
 
-    bool CDBusServer::isDBusAvailable(const QString &dbusAddress, QString &o_message, int timeoutMs)
+    bool CDBusServer::isDBusAvailable(const QString &dBusAddress, QString &message, int timeoutMs)
     {
-        if (dbusAddress.isEmpty()) { o_message = "no address"; return false; }
-        if (isP2PAddress(dbusAddress))
+        if (dBusAddress.isEmpty()) { message = "No address."; return false; }
+        if (isP2PAddress(dBusAddress))
         {
             QString host;
             int port = -1;
-            if (dBusAddressToHostAndPort(dbusAddress, host, port))
-            {
-                return isDBusAvailable(host, port, o_message, timeoutMs);
-            }
-            else
-            {
-                return false;
-            }
+            return CDBusServer::dBusAddressToHostAndPort(dBusAddress, host, port) ?
+                   CDBusServer::isDBusAvailable(host, port, message, timeoutMs) :
+                   false;
         }
         else
         {
-            QString name = coreServiceName();
-            QDBusConnection connection = dbusAddress == systemBusAddress() ?
-                                         QDBusConnection::connectToBus(QDBusConnection::SystemBus, name) :
-                                         QDBusConnection::connectToBus(QDBusConnection::SessionBus, name);
-
-            // todo: further checks would need to go here
-            // failing session bus not detected yet
-
-            o_message = connection.lastError().message();
-            bool isConnected = connection.isConnected();
-
-            QDBusConnection::disconnectFromBus(name);
+            QDBusConnection connection = CDBusServer::connectToDBus(dBusAddress);
+            const bool isConnected = connection.isConnected();
+            message = connection.lastError().message();
+            CDBusServer::disconnectFromDBus(connection, dBusAddress);
             return isConnected;
         }
     }
@@ -416,6 +448,6 @@ namespace BlackMisc
     bool CDBusServer::isDBusAvailable(const QString &dbusAddress, int timeoutMs)
     {
         QString unused;
-        return isDBusAvailable(dbusAddress, unused, timeoutMs);
+        return CDBusServer::isDBusAvailable(dbusAddress, unused, timeoutMs);
     }
 } // namespace

src/blackmisc/dbusserver.h

@@ -85,11 +85,20 @@ namespace BlackMisc
         //! Address denoting a system bus server
         static const QString &systemBusAddress();
 
+        //! Connect to DBus
+        static QDBusConnection connectToDBus(const QString &dbusAddress, const QString &name = {});
+
+        //! Disconnect from Bus/Peer to peer
+        static void disconnectFromDBus(const QDBusConnection &connection, const QString &dBusAddress);
+
         //! Address denoting a P2P server at the given host and port.
         //! \remarks Port number may be embedding in the host string after a colon.
         //! \return p2p address like "tcp:host=foo.bar.com,port=1234"
         static QString p2pAddress(const QString &host, const QString &port = "");
 
+        //! P2P connection name
+        static const QString &p2pConnectionName();
+
         //! Turn something like 127.0.0.1:45000 into "tcp:host=127.0.0.1,port=45000"
         //! \note Handles also "session" and "system" as valid address while CDBusServer::p2pAddress is for
         //! P2P addresses only.
@@ -110,11 +119,15 @@ namespace BlackMisc
         //! Extract host and port from a DBus address
         static bool dBusAddressToHostAndPort(QString dbusAddress, QString &o_host, int &o_port);
 
+        //! Is the given connection one of the default connections?
+        static bool isQtDefaultConnection(const QDBusConnection &connection);
+
         //! Is there a DBus server running at the given address?
+        //! \note This is an incomplete test showing too optimistic results for session DBus
         //! @{
         static bool isDBusAvailable(const QString &host, int port, int timeoutMs = 1500);
-        static bool isDBusAvailable(const QString &host, int port, QString &o_message, int timeoutMs = 1500);
-        static bool isDBusAvailable(const QString &dbusAddress, QString &o_message, int timeoutMs = 1500);
+        static bool isDBusAvailable(const QString &host, int port, QString &message, int timeoutMs = 1500);
+        static bool isDBusAvailable(const QString &dbusAddress, QString &message, int timeoutMs = 1500);
         static bool isDBusAvailable(const QString &dbusAddress, int timeoutMs = 1500);
         //! @}