qt: Implemented logger class to redirect error and info messages to program log widget

Author: bbogush

qt/logger.cpp

@@ -0,0 +1,91 @@
+/*  Copyright (C) 2017 Bogdan Bogush <[email protected]>
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 3.
+ */
+
+#include "logger.h"
+#include <QDebug>
+
+Logger *Logger::logger;
+QTextEdit *Logger::logTextEdit;
+int Logger::refCount;
+
+void Logger::logHandler(QtMsgType type, const QMessageLogContext &context ,
+    const QString &msg)
+{
+    const char *prefix;
+    QString formatMsg;
+
+    (void)context;
+
+    switch (type) {
+    case QtDebugMsg:
+        prefix = "Debug: ";
+        break;
+    case QtInfoMsg:
+        prefix = "Info: ";
+        break;
+    case QtWarningMsg:
+        prefix = "Warning: ";
+        break;
+    case QtCriticalMsg:
+        prefix = "Error: ";
+        break;
+    case QtFatalMsg:
+        prefix = "Fatal error: ";
+        break;
+    }
+
+    formatMsg = QString("%1%2\n").arg(prefix).arg(msg);
+
+    if (type == QtFatalMsg || !logTextEdit)
+    {
+        QByteArray ba = formatMsg.toLatin1();
+        fputs(ba.data(), stderr);
+        if (type == QtFatalMsg)
+            abort();
+    }
+    else
+        logTextEdit->insertPlainText(formatMsg);
+}
+
+Logger::Logger()
+{
+    qInstallMessageHandler(logHandler);
+}
+
+Logger::~Logger()
+{
+    qInstallMessageHandler(0);
+}
+
+Logger *Logger::getInstance()
+{
+    if (!logger)
+        logger = new Logger();
+    refCount++;
+
+    return logger;
+}
+
+void Logger::putInstance()
+{
+    if (!refCount)
+    {
+        qWarning() << "Logger is released without being allocated";
+        return;
+    }
+
+    if (!--refCount && logger)
+    {
+        delete logger;
+        logger = 0;
+        logTextEdit = 0;
+    }
+}
+
+void Logger::setTextEdit(QTextEdit *textEdit)
+{
+    logTextEdit = textEdit;
+}
+

qt/logger.h

@@ -0,0 +1,28 @@
+/*  Copyright (C) 2017 Bogdan Bogush <[email protected]>
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 3.
+ */
+
+#ifndef LOGGER_H
+#define LOGGER_H
+
+#include <QTextEdit>
+
+class Logger
+{
+    static QTextEdit *logTextEdit;
+    static Logger *logger;
+    static int refCount;
+
+    explicit Logger();
+    ~Logger();
+
+    static void logHandler(QtMsgType type, const QMessageLogContext &context,
+        const QString &msg);
+public:
+    static Logger *getInstance();
+    static void putInstance();
+    static void setTextEdit(QTextEdit *textEdit);
+};
+
+#endif // LOGGER_H

qt/main_window.cpp

@@ -6,6 +6,7 @@
 #include "main_window.h"
 #include "ui_main_window.h"
 #include "chip_db.h"
+#include "logger.h"
 #include <QDebug>
 #include <QFileDialog>
 #include <QFile>
@@ -57,8 +58,12 @@ static void addChipDB(QComboBox *chipSelectComboBox)
 MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent),
     ui(new Ui::MainWindow)
 {
+    Logger *logger = Logger::getInstance();
+
     ui->setupUi(this);
 
+    logger->setTextEdit(ui->logTextEdit);
+
     initBufferTable(ui->bufferTableWidget);
 
     prog = new Programmer(this);
@@ -83,14 +88,10 @@ MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent),
 
 MainWindow::~MainWindow()
 {
+    Logger::putInstance();
     delete ui;
 }
 
-void MainWindow::log(QString logMsg)
-{
-    ui->logTextEdit->insertPlainText(logMsg);
-}
-
 void MainWindow::insertBufferRow(quint8 *readBuf, quint32 size, quint32 rowNum,
     quint32 address)
 {
@@ -153,20 +154,18 @@ void MainWindow::slotProgConnect()
 {
     if (!prog->isConnected())
     {
-        if (prog->connect())
-        {
-            log(tr("Failed to connect to programmer\n"));
-            return;
-        }
+        if (!prog->connect())
+            qInfo() << "Connected to programmer";
         else
-            log(tr("Connected to programmer\n"));
+            return;
+
         ui->actionConnect->setText(tr("Disconnect"));
     }
     else
     {
         prog->disconnect();
         ui->actionConnect->setText(tr("Connect"));
-        log(tr("Disconnected from programmer\n"));
+        qInfo() << "Disconnected from programmer";
     }
 }
 
@@ -190,10 +189,8 @@ void MainWindow::slotProgErase()
     QByteArray ba = ui->chipSelectComboBox->currentText().toLatin1();
     ChipInfo *chipInfo = getChipInfoByName(ba.data());
 
-    if (prog->eraseChip(START_ADDRESS, chipInfo->size))
-        log(tr("Failed to erase chip\n"));
-    else
-        log(tr("Chip has been erased successfully\n"));
+    if (!prog->eraseChip(START_ADDRESS, chipInfo->size))
+        qInfo() << "Chip has been erased successfully";
 }
 
 void MainWindow::slotProgRead()
@@ -214,12 +211,9 @@ void MainWindow::slotProgRead()
     ui->bufferTableWidget->setRowCount(HEADER_ROW_NUM);
 
     if (prog->readChip(buf.get(), START_ADDRESS, chipInfo->size))
-    {
-        log(tr("Failed to read chip\n"));
         return;
-    }
     else
-        log(tr("Data has been successfully read\n"));
+        qInfo() << "Data has been successfully read";
 
     for (uint32_t i = 0; i < chipInfo->size; i += ROW_DATA_SIZE)
     {
@@ -267,14 +261,12 @@ void MainWindow::slotProgWrite()
         }
     }
 
-    if (prog->writeChip(buf.get(), START_ADDRESS, bufIter))
-        log(tr("Failed to write chip\n"));
-    else
-        log(tr("Data has been successfully written\n"));
+    if (!prog->writeChip(buf.get(), START_ADDRESS, bufIter))
+        qInfo() << "Data has been successfully written";
 }
 
 void MainWindow::slotSelectChip(int selectedChipNum)
 {
-    if (prog->selectChip(selectedChipNum))
-        log(tr("Failed to select chip"));
+    if (!prog->selectChip(selectedChipNum))
+        qInfo() << "Chip successfully set";
 }

qt/main_window.h

@@ -21,7 +21,6 @@ class MainWindow : public QMainWindow
 public:
     explicit MainWindow(QWidget *parent = 0);
     ~MainWindow();
-    void log(QString logMsg);
 
 private:
     Ui::MainWindow *ui;

qt/qt.pro

@@ -22,13 +22,15 @@ SOURCES += main.cpp\
     programmer.cpp \
     chip_db.cpp \
     serial_port_writer.cpp \
-    serial_port_reader.cpp
+    serial_port_reader.cpp \
+    logger.cpp
 
 HEADERS  += main_window.h \
     programmer.h \
     chip_db.h \
     serial_port_writer.h \
-    serial_port_reader.h
+    serial_port_reader.h \
+    logger.h
 
 FORMS    += main_window.ui