Keep files open while running.

Instead of opening and closing files in /proc, just keep them open
and seek to the beginning each time their data is needed.  Close the
files when exiting.

.gitignore

@@ -33,6 +33,7 @@
 
 moc*
 *Make*
+make-release.sh
 src/sysmon-qt
 *.sav*
 notes

src/sysmon-qt.cpp

@@ -1,12 +1,10 @@
 #include <QAction>
 #include <QApplication>
 #include <QDateTime>
-#include <QFile>
 #include <QHostInfo>
 #include <QRegularExpression>
 #include <QTime>
 #include <QTimer>
-// #include <QMessageBox>
 
 #include "sysmon-qt.h"
 #include "sm_config.h"
@@ -36,6 +34,19 @@ sysmon_qt::sysmon_qt()
    font_size   = settings.value( "fontSize"  , 12 ).toInt();
    font_normal = QFont( font_family, font_size );
 
+   // Files
+   fUptime  = new QFile( "/proc/uptime" );
+   fUptime ->open( QIODevice::ReadOnly | QIODevice::Text);
+
+   fLoadAvg = new QFile( "/proc/loadavg" );
+   fLoadAvg->open( QIODevice::ReadOnly | QIODevice::Text);
+
+   fMemInfo = new QFile( "/proc/meminfo" );
+   fMemInfo->open( QIODevice::ReadOnly | QIODevice::Text);
+
+   fStat    = new QFile( "/proc/stat" );
+   fStat   ->open( QIODevice::ReadOnly | QIODevice::Text);
+
    // Set up palettes
    set_palettes();
 
@@ -98,6 +109,11 @@ sysmon_qt::~sysmon_qt()
    settings.setValue( "positionX", QString::number( position.x() ) );
    settings.setValue( "positionY", QString::number( position.y() ) );
    settings.sync();
+
+   if ( fUptime ->isOpen() ) fUptime ->close();
+   if ( fLoadAvg->isOpen() ) fLoadAvg->close();
+   if ( fMemInfo->isOpen() ) fMemInfo->close();
+   if ( fStat   ->isOpen() ) fStat   ->close();
 }
 
 void sysmon_qt::setup_all()
@@ -178,12 +194,10 @@ void sysmon_qt::update_uptime( void )
    if ( lbl_uptime == nullptr ) return;
    if ( tick % 60  != 0       ) return;  // Update once a minute
 
-   QFile file( "/proc/uptime" );
-   file.open( QIODevice::ReadOnly | QIODevice::Text);
-   QByteArray ba = file.readLine();
-   file.close();
+   fUptime->seek( 0 );
+   QByteArray baUptime = fUptime->readLine();
 
-   QString lineString = QString( ba );
+   QString lineString = QString( baUptime );
    QString upSecs = lineString.left( lineString.indexOf(".") );
 
    uint secs    = upSecs.toInt();
@@ -204,7 +218,8 @@ void sysmon_qt::setup_cpuLoad()
    bool useCPU    = settings.value( "useCPU",    true ).toBool();
    bool useCPUbar = settings.value( "useCPUbar", true ).toBool();
 
-   lbl_cpu = nullptr;
+   lbl_cpu   = nullptr;
+   lbl_loads = nullptr;
 
    if ( ! useCPU && ! useCPUbar ) return;
 
@@ -247,12 +262,10 @@ void sysmon_qt::update_cpu( void )
 
    if ( lbl_loads != nullptr )
    {
-      QFile file( "/proc/loadavg" );
-      file.open( QIODevice::ReadOnly | QIODevice::Text);
-      QByteArray ba2 = file.readLine();
-      file.close();
+      fLoadAvg->seek( 0 );
+      QByteArray ba = fLoadAvg->readLine();
 
-      QString lineString   = QString( ba2 );
+      QString lineString   = QString( ba );
       QStringList loadList = lineString.split( QLatin1Char(' ') );
       QString CPU_loads    = loadList[0] + " " +
                              loadList[1] + " " +
@@ -297,9 +310,8 @@ void sysmon_qt::update_memory( void )
    if ( lbl_memory            == nullptr ) return;
    if ( tick % memory_refresh != 0       ) return;
 
-   QFile file( "/proc/meminfo" );
-   file.open( QIODevice::ReadOnly | QIODevice::Text);
-   QTextStream textStream( &file );
+   fMemInfo->seek( 0 );
+   QTextStream textStream( fMemInfo );
 
    QString MemTotal;
    QString MemAvailable;
@@ -314,7 +326,6 @@ void sysmon_qt::update_memory( void )
         break;
      }
    }
-   file.close();
 
    QRegularExpression re( "\\d+" );
    QRegularExpressionMatch match = re.match( MemTotal );
@@ -591,7 +602,6 @@ void sysmon_qt::update_cpu_percentage( void )
    // Could possibly do it every cpu_refresh time (3 seconds for now)
    static qint64      previousJiffiesWork;
    static qint64      previousJiffiesTotal;
-   static QFile*      file;
 
    QString cpu;  // Not really used -- always "cpu"
    qint64  user, // jiffies
@@ -602,16 +612,16 @@ void sysmon_qt::update_cpu_percentage( void )
    // First time through only
    if ( previousJiffiesWork == 0 )
    {
-      file = new QFile( "/proc/stat" );
-      file->open( QIODevice::ReadOnly | QIODevice::Text);
-      QTextStream stream( file );
+      fStat->seek( 0 );
+      QTextStream stream( fStat );
       stream >> cpu >> user >> nice >> system >> idle;
+
       previousJiffiesWork  = user + nice + system;
       previousJiffiesTotal = previousJiffiesWork + idle;
       return;
    }
 
-   QTextStream stream( file );
+   QTextStream stream( fStat );
    stream.seek( 0 );  // Just read the first line each time
    stream >> cpu >> user >> nice >> system >> idle;
 

src/sysmon-qt.h

@@ -2,6 +2,7 @@
 #define SYSMONQT_H
 
 #include <QFont>
+#include <QFile>
 #include <QLabel>
 #include <QLayout>
 #include <QMainWindow>
@@ -29,25 +30,30 @@ public slots:
    QLabel* textlabel( const QString&, int = -1, int = QFont::Normal );
    QLabel* banner   ( const QString&, int =  0, int = QFont::Bold );
 
-   int       tick            = 0;     // tick every second
-   int       cpu_refresh     = 3;
-   int       memory_refresh  = 3;
-   int       temp_refresh    = 5;
-   int       tempsCount;
-   int       cpuPercentage;
-   bool      pauseUpdate     = false;
-   bool      mFrame          = false; // turn frame on and off
-   bool      pauseTempUpdate = false; // turn temperature update on and off
-   QString   TZ;                      // time zone
-   QPoint    position;                // location of widget
-
-   QLabel*   lbl_hostname;
-   QLabel*   lbl_time;     // time of day
-   QLabel*   lbl_date;     
-   QLabel*   lbl_uptime;
-   QLabel*   lbl_cpu;      // title
-   QLabel*   lbl_loads;    // label for memory
-   QLabel*   lbl_memory;   // title
+   int        tick            = 0;     // tick every second
+   int        cpu_refresh     = 3;
+   int        memory_refresh  = 3;
+   int        temp_refresh    = 5;
+   int        tempsCount;
+   int        cpuPercentage;
+   bool       pauseUpdate     = false;
+   bool       mFrame          = false; // turn frame on and off
+   bool       pauseTempUpdate = false; // turn temperature update on and off
+   QString    TZ;                      // time zone
+   QPoint     position;                // location of widget
+
+   QLabel*    lbl_hostname;
+   QLabel*    lbl_time;     // time of day
+   QLabel*    lbl_date;     
+   QLabel*    lbl_uptime;
+   QLabel*    lbl_cpu;      // title
+   QLabel*    lbl_loads;    // label for memory
+   QLabel*    lbl_memory;   // title
+
+   QFile*     fUptime;
+   QFile*     fLoadAvg;
+   QFile*     fMemInfo;
+   QFile*     fStat;
 
    QProgressBar* memory;
    QProgressBar* load;