/**************************************************************************
**
** This code is part of Qt Creator
**
** Copyright (c) 2011 Nokia Corporation and/or its subsidiary(-ies).
**
** Contact: Nokia Corporation (info@qt.nokia.com)
**
**
** GNU Lesser General Public License Usage
**
** This file may be used under the terms of the GNU Lesser General Public
** License version 2.1 as published by the Free Software Foundation and
** appearing in the file LICENSE.LGPL included in the packaging of this file.
** Please review the following information to ensure the GNU Lesser General
** Public License version 2.1 requirements will be met:
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** Other Usage
**
** Alternatively, this file may be used in accordance with the terms and
** conditions contained in a signed written agreement between you and Nokia.
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**************************************************************************/

#include "processlist.h"

#include <common/probeabidetector.h>

#include <QProcess>
#include <QDir>

#include <algorithm>
#include <functional>

static GammaRay::ProbeABIDetector s_abiDetector;

static bool isUnixProcessId(const QString &procname)
{
  for (int i = 0; i != procname.size(); ++i) {
    if (!procname.at(i).isDigit()) {
      return false;
    }
  }
  return true;
}

struct PidAndNameMatch : public std::unary_function<ProcData,bool> {

  explicit PidAndNameMatch(const QString &ppid, const QString &name)
    : m_ppid(ppid), m_name(name)
  {
  }

  bool operator()(const ProcData &p) const
  {
    return p.ppid == m_ppid && m_name == p.name;
  }

  const QString m_ppid;
  const QString m_name;
};

// Determine UNIX processes by running ps
static ProcDataList unixProcessListPS(const ProcDataList &previous)
{
#ifdef Q_OS_MAC
  // command goes last, otherwise it is cut off
  static const char formatC[] = "pid state user command";
#else
  static const char formatC[] = "pid,state,user,cmd";
#endif
  ProcDataList rc;
  QProcess psProcess;
  QStringList args;
  args << QLatin1String("-e") << QLatin1String("-o") << QLatin1String(formatC);
  psProcess.start(QLatin1String("ps"), args);
  if (!psProcess.waitForStarted()) {
    return rc;
  }
  psProcess.waitForFinished();
  QByteArray output = psProcess.readAllStandardOutput();
  // Split "457 S+   /Users/foo.app"
  const QStringList lines = QString::fromLocal8Bit(output).split(QLatin1Char('\n'));
  const int lineCount = lines.size();
  const QChar blank = QLatin1Char(' ');
  for (int l = 1; l < lineCount; l++) { // Skip header
    const QString line = lines.at(l).simplified();
    // we can't just split on blank as the process name might
    // contain them
    const int endOfPid = line.indexOf(blank);
    const int endOfState = line.indexOf(blank, endOfPid+1);
    const int endOfUser = line.indexOf(blank, endOfState+1);
    if (endOfPid >= 0 && endOfState >= 0 && endOfUser >= 0) {
      ProcData procData;
      procData.ppid = line.left(endOfPid);
      procData.state = line.mid(endOfPid+1, endOfState-endOfPid-1);
      procData.user = line.mid(endOfState+1, endOfUser-endOfState-1);
      procData.name = line.right(line.size()-endOfUser-1);
      ProcDataList::ConstIterator it =
        std::find_if(previous.constBegin(), previous.constEnd(),
                     PidAndNameMatch(procData.ppid, procData.name));
      if (it != previous.constEnd()) {
        procData.abi = it->abi;
      } else {
        procData.abi = s_abiDetector.abiForProcess(procData.ppid.toLongLong());
      }
      rc.push_back(procData);
    }
  }

  return rc;
}

// Determine UNIX processes by reading "/proc". Default to ps if
// it does not exist
ProcDataList processList(const ProcDataList &previous)
{
  const QDir procDir(QLatin1String("/proc/"));
  if (!procDir.exists()) {
    return unixProcessListPS(previous);
  }
  ProcDataList rc;
  const QStringList procIds = procDir.entryList();
  if (procIds.isEmpty()) {
    return rc;
  }
  foreach (const QString &procId, procIds) {
    if (!isUnixProcessId(procId)) {
      continue;
    }
    QString filename = QLatin1String("/proc/");
    filename += procId;
    filename += QLatin1String("/stat");
    QFile file(filename);
    if (!file.open(QIODevice::ReadOnly)) {
      continue;           // process may have exited
    }

    const QStringList data = QString::fromLocal8Bit(file.readAll()).split(' ');
    ProcData proc;
    proc.ppid = procId;
    proc.name = data.at(1);
    if (proc.name.startsWith(QLatin1Char('(')) && proc.name.endsWith(QLatin1Char(')'))) {
      proc.name.truncate(proc.name.size() - 1);
      proc.name.remove(0, 1);
    }
    proc.state = data.at(2);
    // PPID is element 3

    proc.user = QFileInfo(file).owner();
    file.close();

    QFile cmdFile(QLatin1String("/proc/") + procId + QLatin1String("/cmdline"));
    if(cmdFile.open(QFile::ReadOnly)) {
      QByteArray cmd = cmdFile.readAll();
      cmd.replace('\0', ' ');
      if (!cmd.isEmpty()) {
        proc.name = QString::fromLocal8Bit(cmd).trimmed();
      }
    }
    cmdFile.close();

    proc.abi = s_abiDetector.abiForProcess(procId.toLongLong());

    rc.push_back(proc);
  }
  return rc;
}
