/*  This file is part of the KDE project

    Copyright (C) 2007 John Tapsell <tapsell@kde.org>

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LIB.  If not, write to
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA 02110-1301, USA.

*/

#ifndef PROCESSES_BASE_P_H
#define PROCESSES_BASE_P_H

#include <QSet>
#include <QObject>
#include "processes.h"

namespace KSysGuard
{
    class Process;
    /**
     * This class contains the specific code to get the processes from the given host.
     *
     * To port this to other operating systems you need to make a processes_(osname).cpp  file
     * which implements all of the function below.  If you need private functions/variables etc put them in
     * the Private class.
     *
     * @author John Tapsell <tapsell@kde.org>
     */
    class AbstractProcesses : public QObject
    {
        Q_OBJECT

        public:

            AbstractProcesses() { errorCode = Processes::Unknown; }
            ~AbstractProcesses() override {}

            /** \brief Get a set of the currently running process PIDs.
             *
             *  To get information about processes, this will be the first function called.
             */
            virtual QSet<long> getAllPids() = 0;

            /** \brief Return the parent PID for the given process PID.
             *
             *  For each of the PIDs that getAllPids() returns, getParentPid will be called.
             *  This is used to setup the tree structure.
             *  For a particular PID, this is guaranteed to be called before updateProcessInfo for that PID.
             *  However this may be called several times in a row before the updateProcessInfo is called, so be careful
             *  if you want to try to preserve state in Private.
             */
            virtual long getParentPid(long pid) = 0;

            /** \brief Fill in the given Process class with information for given PID.
             *
             *  This will be called for every PID, after getParentPid() has been called for the same parameter.
             *
             *  The process->pid() process->ppid and process->parent  are all guaranteed
             *  to be filled in correctly and process->parent will be non null.
             */
            virtual bool updateProcessInfo(long pid, Process *process) = 0;

            /** \brief Send the specified named POSIX signal to the process given.
             *
             *  For example, to indicate for process 324 to STOP do:
             *  \code
             *    #include <signals.h>
             *     ...
             *
             *    KSysGuard::Processes::sendSignal(324, SIGSTOP);
             *  \endcode
             *
             */
            virtual bool sendSignal(long pid, int sig) = 0;

            /** \brief Set the priority for a process.
             *
             *  For the normal scheduler, this is usually from 19
             *  (very nice, lowest priority) to -20 (highest priority).  The default value for a process is 0.
             *
             *  This has no effect if the scheduler is not the normal one (SCHED_OTHER in Linux).
             *
             *  @return false if you do not have permission to set the priority.
             */
            virtual bool setNiceness(long pid, int priority) = 0;

            /** \brief Set the scheduler for a process.
             *
             * This is defined according to POSIX.1-2001
             *  See "man sched_setscheduler" for more information.
             *
             *  @p priorityClass One of SCHED_FIFO, SCHED_RR, SCHED_OTHER, and SCHED_BATCH
             *  @p priority Set to 0 for SCHED_OTHER and SCHED_BATCH.  Between 1 and 99 for SCHED_FIFO and SCHED_RR
             *  @return false if you do not have permission to set the priority
             */
            virtual bool setScheduler(long pid, int priorityClass, int priority) = 0;

            /** \brief Return the total amount of physical memory in KiB.
             *
             *  This is fast (just a system call in most OSes)
             *  Returns 0 on error
             */
            virtual long long totalPhysicalMemory() = 0;

            /** \brief Set the i/o priority for a process.
             *
             *  This is from 7 (very nice, lowest i/o priority) to
             *  0 (highest priority).  The default value is determined as: io_nice = (cpu_nice + 20) / 5.
             *
             *  @return false if you do not have permission to set the priority
             */
            virtual bool setIoNiceness(long pid, int priorityClass, int priority) = 0;

            /** \brief Returns true if ionice is supported on this system
             */
            virtual bool supportsIoNiceness() = 0;

            /** \brief Return the number of processor cores enabled.
             *
             *  (A system can disable processors.  Disabled processors are not counted here).
             *  This is fast (just a system call on most OSes) */
            virtual long numberProcessorCores() = 0;

            /** \brief Update the process information for all processes.
             *
             *  Get all the current process information from the machine.  When done, emit updateAllProcesses().
             */
            virtual void updateAllProcesses( Processes::UpdateFlags updateFlags ) = 0;

            Processes::Error errorCode;
Q_SIGNALS:
            /** \brief This is emitted when the processes have been updated, and the view should be refreshed.
             */
            void processesUpdated();
    };
}

#endif // PROCESSES_BASE_P_H
