runtime/nepomuk/server/processcontrol.h

   1 /***************************************************************************
   2  *   Copyright (C) 2006 by Tobias Koenig <tokoe@kde.org>                   *
   3  *   Copyright (C) 2008 by Sebastian Trueg <trueg@kde.org>                 *
   4  *                                                                         *
   5  *   This program is free software; you can redistribute it and/or modify  *
   6  *   it under the terms of the GNU Library General Public License as       *
   7  *   published by the Free Software Foundation; either version 2 of the    *
   8  *   License, or (at your option) any later version.                       *
   9  *                                                                         *
  10  *   This program is distributed in the hope that it will be useful,       *
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  13  *   GNU General Public License for more details.                          *
  14  *                                                                         *
  15  *   You should have received a copy of the GNU Library General Public     *
  16  *   License along with this program; if not, write to the                 *
  17  *   Free Software Foundation, Inc.,                                       *
  18  *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.         *
  19  ***************************************************************************/
  20
  21 #ifndef _PROCESSCONTROL_H
  22 #define _PROCESSCONTROL_H
  23
  24 #include <QtCore/QObject>
  25 #include <QtCore/QProcess>
  26
  27
  28 /**
  29  * This class starts and observes a process. Depending on the
  30  * policy it also restarts the process when it crashes.
  31  */
  32 class ProcessControl : public QObject
  33 {
  34     Q_OBJECT
  35
  36 public:
  37     /**
  38      * Theses enums describe the behaviour when the observed
  39      * application crashed.
  40      *
  41      * @li StopOnCrash    - The application won't be restarted.
  42      * @li RestartOnCrash - The application is restarted with the same arguments.
  43      */
  44     enum CrashPolicy
  45     {
  46         StopOnCrash,
  47         RestartOnCrash
  48     };
  49
  50     /**
  51      * Creates a new process control.
  52      *
  53      * @param parent The parent object.
  54      */
  55     ProcessControl( QObject *parent = 0 );
  56
  57     /**
  58      * Destroys the process control.
  59      */
  60     ~ProcessControl();
  61
  62     /**
  63      * Starts the @p application with the given list of @p arguments.
  64      */
  65     bool start( const QString &application, const QStringList &arguments = QStringList(),
  66                 CrashPolicy policy = RestartOnCrash, int maxCrashes = 5 );
  67
  68     /**
  69      * Stops the currently running application.
  70      */
  71     void stop();
  72
  73     /**
  74      * Sets the crash policy.
  75      */
  76     void setCrashPolicy( CrashPolicy policy );
  77
  78     bool isRunning() const;
  79
  80 Q_SIGNALS:
  81     /**
  82      * This signal is emitted whenever the observed application
  83      * writes something to stderr.
  84      *
  85      * @param errorMsg The error output of the observed application.
  86      */
  87     void processErrorMessages( const QString &errorMsg );
  88
  89     void finished( bool clean );
  90
  91 private Q_SLOTS:
  92     void slotError( QProcess::ProcessError );
  93     void slotFinished( int, QProcess::ExitStatus );
  94     void slotErrorMessages();
  95     void slotStdoutMessages();
  96
  97 private:
  98     bool start();
  99
 100     QProcess mProcess;
 101     QString mApplication;
 102     QStringList mArguments;
 103     CrashPolicy mPolicy;
 104     bool mFailedToStart;
 105     int mCrashCount;
 106 };
 107
 108 #endif