Logger.cpp

   1 /*
   2  * This file is part of the vng project
   3  * Copyright (C) 2008 Thomas Zander <tzander@trolltech.com>
   4  *
   5  * This program is free software: you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation, either version 3 of the License, or
   8  * (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 General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include "Logger.h"
  20 #include <QProcess>
  21 #include <QDebug>
  22
  23 class NullDevice : public QIODevice {
  24 public:
  25     virtual qint64 readData (char *data, qint64 maxlen) {
  26         Q_UNUSED(data);
  27         Q_UNUSED(maxlen);
  28         return 0;
  29     }
  30     virtual qint64 writeData (const char *data, qint64 len) {
  31         Q_UNUSED(data);
  32         return len;
  33     }
  34 };
  35
  36 class LoggerPrivate {
  37 public:
  38     LoggerPrivate()
  39         : verbosity(Logger::Chatty),
  40         dummy(new NullDevice()),
  41         standardOut(stdout),
  42         pagerStream(0),
  43         pager(0),
  44         colorPager(false)
  45     {
  46     }
  47
  48     ~LoggerPrivate() {
  49         standardOut.flush();
  50         removePager();
  51     }
  52
  53     void insertPager()
  54     {
  55         if (pager)
  56             return; // already present.
  57         pager = new QProcess();
  58         pager->setProcessChannelMode(QProcess::ForwardedChannels);
  59         colorPager = true;
  60         if (! startPager("less", QStringList() << "-R" << "-E")) {
  61             colorPager = false;
  62             if (! startPager("less", QStringList() << "-E")) {
  63                 if (! startPager("more")) {
  64                     delete pager;
  65                     pager = 0;
  66                     return;
  67                 }
  68             }
  69         }
  70         pagerStream = new QTextStream(pager);
  71     }
  72
  73     void removePager()
  74     {
  75         if (pager == 0)
  76             return;
  77         pagerStream->flush();
  78         pager->closeWriteChannel();
  79         pager->waitForFinished(-1);
  80         delete pager;
  81         pager = 0;
  82         delete pagerStream;
  83         pagerStream = 0;
  84     }
  85
  86     bool startPager(const QString &program, const QStringList &arguments = QStringList())
  87     {
  88         Q_ASSERT(pager);
  89         pager->start(program, arguments, QIODevice::ReadWrite);
  90         if (! pager->waitForStarted()) {
  91             if (pager->state() != QProcess::NotRunning) { // time out
  92                 standardOut << "ERROR: the pager failed to start" << endl;
  93                 pager->kill();
  94             }
  95             return false;
  96         }
  97         if (pager->state() != QProcess::Running) // it already 'finished'
  98             return false;
  99         return true;
 100     }
 101
 102     Logger::Verbosity verbosity;
 103     QTextStream dummy;
 104     QTextStream standardOut;
 105     QTextStream *pagerStream;
 106     QProcess *pager;
 107     bool colorPager;
 108 };
 109
 110 Q_GLOBAL_STATIC(LoggerPrivate, _vng_logger_private)
 111
 112
 113 Logger::Logger()
 114     : d(_vng_logger_private())
 115 {
 116 }
 117
 118 void Logger::setVerbosity(Verbosity verbosity)
 119 {
 120     _vng_logger_private()->verbosity = verbosity;
 121 }
 122
 123 Logger::Verbosity Logger::verbosity()
 124 {
 125     return _vng_logger_private()->verbosity;
 126 }
 127
 128 QTextStream & Logger::standardOut()
 129 {
 130     LoggerPrivate *self = _vng_logger_private();
 131     if (self->pagerStream)
 132         return *self->pagerStream;
 133     return self->standardOut;
 134 }
 135
 136 QTextStream &Logger::log(Verbosity verbosity)
 137 {
 138     LoggerPrivate *self = _vng_logger_private();
 139     if (self->verbosity >= verbosity) {
 140         if (self->pagerStream)
 141             return *self->pagerStream;
 142         return self->standardOut;
 143     }
 144     return self->dummy;
 145 }
 146
 147
 148 QTextStream & Logger::debug()
 149 {
 150     return log(Debug);
 151 }
 152
 153 QTextStream & Logger::info()
 154 {
 155     return log(Chatty);
 156 }
 157
 158 QTextStream & Logger::warn()
 159 {
 160     return log(Verbose);
 161 }
 162
 163 QTextStream & Logger::error()
 164 {
 165     return log(Quiet);
 166 }
 167
 168 void Logger::startPager()
 169 {
 170     _vng_logger_private()->insertPager();
 171 }
 172
 173 void Logger::stopPager()
 174 {
 175     _vng_logger_private()->removePager();
 176 }
 177
 178
 179 bool Logger::hasNonColorPager()
 180 {
 181     if (_vng_logger_private()->pager == 0)
 182         return false;
 183     return ! _vng_logger_private()->colorPager;
 184 }