Restructure logging utilities

Create a singleton-pattern class as an encapsulation unit for holding
and altering the state of debug printing attributes. Move related code
from various places under a single umbrella header file for logging
utilities, with some minor stylistic changes & cleanup.

This acts as a preparatory change for providing non-blocking headless
CLI runs when there is no TTY attached - that will be fixed in a
follow-up change.

Change-Id: Ib7f72cf75362c3ea6713058e92eda997d6df55c3
Reviewed-by: Katja Marttila <katja.marttila@qt.io>

20 files changed, 684 insertions, 559 deletions

diff --git a/src/libs/installer/init.cpp b/src/libs/installer/init.cpp
index c1326824a..4aa65296f 100644
--- a/src/libs/installer/init.cpp
+++ b/src/libs/installer/init.cpp
@@ -1,6 +1,6 @@
 /**************************************************************************
 **
-** Copyright (C) 2020 The Qt Company Ltd.
+** Copyright (C) 2021 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Installer Framework.
@@ -47,24 +47,14 @@
 #include "licenseoperation.h"
 #include "settingsoperation.h"
 #include "consumeoutputoperation.h"
-#include "globals.h"
+#include "loggingutils.h"
 
 #include "lib7z_facade.h"
-#include "utils.h"
 
 #include "updateoperationfactory.h"
 #include "filedownloaderfactory.h"
 
 #include <QtPlugin>
-#include <QElapsedTimer>
-
-#include <iostream>
-
-#if defined(Q_OS_UNIX)
-#include <unistd.h>
-#elif defined(Q_OS_WIN)
-#include <fileapi.h>
-#endif
 
 using namespace KDUpdater;
 using namespace QInstaller;
@@ -76,84 +66,6 @@ static void initResources()
 }
 #endif
 
-static bool s_outputRedirected = false;
-
-static QString trimAndPrepend(QtMsgType type, const QString &msg)
-{
-    QString ba(msg);
-    // last character is a space from qDebug
-    if (ba.endsWith(QLatin1Char(' ')))
-        ba.chop(1);
-
-    // remove quotes if the whole message is surrounded with them
-    if (ba.startsWith(QLatin1Char('"')) && ba.endsWith(QLatin1Char('"')))
-        ba = ba.mid(1, ba.length() - 2);
-
-    // prepend the message type, skip QtDebugMsg
-    switch (type) {
-        case QtWarningMsg:
-            ba.prepend(QStringLiteral("Warning: "));
-        break;
-
-        case QtCriticalMsg:
-            ba.prepend(QStringLiteral("Critical: "));
-        break;
-
-        case QtFatalMsg:
-            ba.prepend(QStringLiteral("Fatal: "));
-        break;
-
-        default:
-            break;
-    }
-    return ba;
-}
-
-// start timer on construction (so we can use it as static member)
-class Uptime : public QElapsedTimer {
-public:
-    Uptime() { start(); }
-};
-
-void messageHandler(QtMsgType type, const QMessageLogContext &context, const QString &msg)
-{
-    // suppress warning from QPA minimal plugin
-    if (msg.contains(QLatin1String("This plugin does not support propagateSizeHints")))
-        return;
-
-    if (context.category == lcProgressIndicator().categoryName()) {
-        if (!s_outputRedirected)
-            std::cout << msg.toStdString() << "\r" << std::flush;
-        return;
-    }
-
-    static Uptime uptime;
-
-    QString ba;
-    if (context.category != lcPackageInfo().categoryName()) {
-        ba = QLatin1Char('[') + QString::number(uptime.elapsed()) + QStringLiteral("] ");
-    }
-    ba += trimAndPrepend(type, msg);
-
-    if (type != QtDebugMsg && context.file) {
-        ba += QString(QStringLiteral(" (%1:%2, %3)")).arg(
-                    QString::fromLatin1(context.file)).arg(context.line).arg(
-                    QString::fromLatin1(context.function));
-    }
-
-    if (VerboseWriter *log = VerboseWriter::instance())
-        log->appendLine(ba);
-
-    if (type != QtDebugMsg || isVerbose())
-        std::cout << qPrintable(ba) << std::endl;
-
-    if (type == QtFatalMsg) {
-        QtMessageHandler oldMsgHandler = qInstallMessageHandler(nullptr);
-        qt_message_output(type, context, msg);
-        qInstallMessageHandler(oldMsgHandler);
-    }
-}
-
 /*!
     Initializes the 7z library and installer resources. Registers
     custom operations and installs a custom message handler.
@@ -190,10 +102,8 @@ void QInstaller::init()
 
     FileDownloaderFactory::setFollowRedirects(true);
 
-#if defined(Q_OS_UNIX)
-    s_outputRedirected = !isatty(fileno(stdout));
-#elif defined(Q_OS_WIN)
-    s_outputRedirected = (GetFileType(GetStdHandle(STD_OUTPUT_HANDLE)) == FILE_TYPE_DISK);
-#endif
+    auto messageHandler = [](QtMsgType type, const QMessageLogContext &context, const QString &msg) {
+        LoggingHandler::instance().messageHandler(type, context, msg);
+    };
     qInstallMessageHandler(messageHandler);
 }
diff --git a/src/libs/installer/installer.pro b/src/libs/installer/installer.pro
index 437ab002f..bc4fcbb39 100644
--- a/src/libs/installer/installer.pro
+++ b/src/libs/installer/installer.pro
@@ -44,6 +44,7 @@ win32:QT += winextras
 
 HEADERS += packagemanagercore.h \
     aspectratiolabel.h \
+    loggingutils.h \
     packagemanagercore_p.h \
     packagemanagergui.h \
     binaryformat.h \
@@ -137,11 +138,11 @@ HEADERS += packagemanagercore.h \
     repositorycategory.h \
     componentselectionpage_p.h \
     commandlineparser.h \
-    commandlineparser_p.h \
-    printoutput.h
+    commandlineparser_p.h
 
 SOURCES += packagemanagercore.cpp \
     aspectratiolabel.cpp \
+    loggingutils.cpp \
     packagemanagercore_p.cpp \
     packagemanagergui.cpp \
     binaryformat.cpp \
@@ -216,8 +217,7 @@ SOURCES += packagemanagercore.cpp \
     packagesource.cpp \
     repositorycategory.cpp \
     componentselectionpage_p.cpp \
-    commandlineparser.cpp \
-    printoutput.cpp
+    commandlineparser.cpp
 
 FORMS += proxycredentialsdialog.ui \
     serverauthenticationdialog.ui
diff --git a/src/libs/installer/loggingutils.cpp b/src/libs/installer/loggingutils.cpp
new file mode 100644
index 000000000..bd3bdbc3d
--- /dev/null
+++ b/src/libs/installer/loggingutils.cpp
@@ -0,0 +1,505 @@
+/**************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Installer Framework.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+**************************************************************************/
+
+#include "loggingutils.h"
+
+#include "component.h"
+#include "localpackagehub.h"
+#include "globals.h"
+#include "fileutils.h"
+#include "remoteclient.h"
+#include "remotefileengine.h"
+
+#include <QDomDocument>
+#include <QElapsedTimer>
+
+#include <iostream>
+#if defined(Q_OS_UNIX)
+#include <unistd.h>
+#elif defined(Q_OS_WIN)
+#include <fileapi.h>
+#endif
+
+namespace QInstaller {
+
+/*!
+    \class QInstaller::LoggingHandler
+    \inmodule QtInstallerFramework
+    \brief The LoggingHandler class provides methods for manipulating the
+    application-wide verbosiveness and format of printed debug messages.
+
+    The class also contains utility methods for printing common preformatted messages.
+*/
+
+/*!
+    \inmodule QtInstallerFramework
+    \class QInstaller::Uptime
+    \internal
+*/
+
+/*!
+    \inmodule QtInstallerFramework
+    \class QInstaller::VerboseWriter
+    \internal
+*/
+
+/*!
+    \inmodule QtInstallerFramework
+    \class QInstaller::VerboseWriterOutput
+    \internal
+*/
+
+/*!
+    \inmodule QtInstallerFramework
+    \class QInstaller::PlainVerboseWriterOutput
+    \internal
+*/
+
+/*!
+    \inmodule QtInstallerFramework
+    \class QInstaller::VerboseWriterAdminOutput
+    \internal
+*/
+
+/*!
+    \enum LoggingHandler::VerbosityLevel
+    \brief This enum holds the possible levels of output verbosity.
+
+    \value Silent
+    \value Normal
+    \value Detailed
+    \value Minimum
+           Minimum possible verbosity level. Synonym for \c VerbosityLevel::Silent.
+    \value Maximum
+           Maximum possible verbosity level. Synonym for \c VerbosityLevel::Detailed.
+*/
+
+// start timer on construction (so we can use it as static member)
+class Uptime : public QElapsedTimer {
+public:
+    Uptime() { start(); }
+};
+
+/*!
+    \internal
+*/
+LoggingHandler::LoggingHandler()
+    : m_verbLevel(VerbosityLevel::Silent)
+{
+#if defined(Q_OS_UNIX)
+    m_outputRedirected = !isatty(fileno(stdout));
+#elif defined(Q_OS_WIN)
+    m_outputRedirected = (GetFileType(GetStdHandle(STD_OUTPUT_HANDLE)) == FILE_TYPE_DISK);
+#endif
+}
+
+/*!
+    \internal
+*/
+LoggingHandler::~LoggingHandler()
+{
+}
+
+/*!
+    Prints out preformatted debug messages, warnings, critical and fatal error messages
+    specified by \a msg and \a type. The message \a context provides information about
+    the source code location the message was generated.
+*/
+void LoggingHandler::messageHandler(QtMsgType type, const QMessageLogContext &context, const QString &msg)
+{
+    // suppress warning from QPA minimal plugin
+    if (msg.contains(QLatin1String("This plugin does not support propagateSizeHints")))
+        return;
+
+    if (context.category == lcProgressIndicator().categoryName()) {
+        if (!outputRedirected())
+            std::cout << msg.toStdString() << "\r" << std::flush;
+        return;
+    }
+
+    static Uptime uptime;
+
+    QString ba;
+    if (context.category != lcPackageInfo().categoryName()) {
+        ba = QLatin1Char('[') + QString::number(uptime.elapsed()) + QStringLiteral("] ");
+    }
+    ba += trimAndPrepend(type, msg);
+
+    if (type != QtDebugMsg && context.file) {
+        ba += QString(QStringLiteral(" (%1:%2, %3)")).arg(
+                    QString::fromLatin1(context.file)).arg(context.line).arg(
+                    QString::fromLatin1(context.function));
+    }
+
+    if (VerboseWriter *log = VerboseWriter::instance())
+        log->appendLine(ba);
+
+    if (type != QtDebugMsg || isVerbose())
+        std::cout << qPrintable(ba) << std::endl;
+
+    if (type == QtFatalMsg) {
+        QtMessageHandler oldMsgHandler = qInstallMessageHandler(nullptr);
+        qt_message_output(type, context, msg);
+        qInstallMessageHandler(oldMsgHandler);
+    }
+}
+
+/*!
+    Trims the trailing space character and surrounding quotes from \a msg.
+    Also prepends the message \a type to the message.
+*/
+QString LoggingHandler::trimAndPrepend(QtMsgType type, const QString &msg) const
+{
+    QString ba(msg);
+    // last character is a space from qDebug
+    if (ba.endsWith(QLatin1Char(' ')))
+        ba.chop(1);
+
+    // remove quotes if the whole message is surrounded with them
+    if (ba.startsWith(QLatin1Char('"')) && ba.endsWith(QLatin1Char('"')))
+        ba = ba.mid(1, ba.length() - 2);
+
+    // prepend the message type, skip QtDebugMsg
+    switch (type) {
+        case QtWarningMsg:
+            ba.prepend(QStringLiteral("Warning: "));
+        break;
+
+        case QtCriticalMsg:
+            ba.prepend(QStringLiteral("Critical: "));
+        break;
+
+        case QtFatalMsg:
+            ba.prepend(QStringLiteral("Fatal: "));
+        break;
+
+        default:
+            break;
+    }
+    return ba;
+}
+
+/*!
+    Returns the only instance of this class.
+*/
+LoggingHandler &LoggingHandler::instance()
+{
+    static LoggingHandler instance;
+    return instance;
+}
+
+/*!
+    Sets to verbose output if \a v is set to \c true. Calling this multiple
+    times increases or decreases the verbosity level accordingly.
+*/
+void LoggingHandler::setVerbose(bool v)
+{
+    if (v)
+        m_verbLevel++;
+    else
+        m_verbLevel--;
+}
+
+/*!
+    Returns \c true if the installer is set to verbose output.
+*/
+bool LoggingHandler::isVerbose() const
+{
+    return m_verbLevel != VerbosityLevel::Silent;
+}
+
+/*!
+    Returns the current verbosity level.
+*/
+LoggingHandler::VerbosityLevel LoggingHandler::verboseLevel() const
+{
+    return m_verbLevel;
+}
+
+/*!
+    Returns \c true if output is redirected, i.e. to a file.
+*/
+bool LoggingHandler::outputRedirected() const
+{
+    return m_outputRedirected;
+}
+
+/*!
+    Prints basic information about \a components.
+*/
+void LoggingHandler::printComponentInfo(const QList<Component *> components) const
+{
+    QDomDocument doc;
+    QDomElement root = doc.createElement(QLatin1String("updates"));
+    doc.appendChild(root);
+
+    foreach (Component *component, components) {
+        QDomElement update = doc.createElement(QLatin1String("update"));
+        update.setAttribute(QLatin1String("name"), component->value(scDisplayName));
+        update.setAttribute(QLatin1String("version"), component->value(scVersion));
+        update.setAttribute(QLatin1String("size"), component->value(scUncompressedSize));
+        update.setAttribute(QLatin1String("id"), component->value(scName));
+        root.appendChild(update);
+    }
+    qCDebug(lcPackageInfo) << qPrintable(doc.toString(4));
+}
+
+/*!
+    Prints basic or more detailed information about local \a packages,
+    depending on the current verbosity level.
+*/
+void LoggingHandler::printLocalPackageInformation(const QList<KDUpdater::LocalPackage> &packages) const
+{
+    QDomDocument doc;
+    QDomElement root = doc.createElement(QLatin1String("localpackages"));
+    doc.appendChild(root);
+    foreach (KDUpdater::LocalPackage package, packages) {
+        QDomElement update = doc.createElement(QLatin1String("package"));
+        update.setAttribute(QLatin1String("name"), package.name);
+        update.setAttribute(QLatin1String("displayname"), package.title);
+        update.setAttribute(QLatin1String("version"), package.version);
+        if (verboseLevel() == VerbosityLevel::Detailed) {
+            update.setAttribute(QLatin1String("description"), package.description);
+            update.setAttribute(QLatin1String("dependencies"), package.dependencies.join(QLatin1Char(',')));
+            update.setAttribute(QLatin1String("autoDependencies"), package.autoDependencies.join(QLatin1Char(',')));
+            update.setAttribute(QLatin1String("virtual"), package.virtualComp);
+            update.setAttribute(QLatin1String("forcedInstallation"), package.forcedInstallation);
+            update.setAttribute(QLatin1String("checkable"), package.checkable);
+            update.setAttribute(QLatin1String("uncompressedSize"), package.uncompressedSize);
+            update.setAttribute(QLatin1String("installDate"), package.installDate.toString());
+            update.setAttribute(QLatin1String("lastUpdateDate"), package.lastUpdateDate.toString());
+        }
+        root.appendChild(update);
+    }
+    qCDebug(lcPackageInfo) << qPrintable(doc.toString(4));
+}
+
+/*!
+    Prints basic or more detailed information about available \a matchedPackages,
+    depending on the current verbosity level. If a package is also present in \a installedPackages,
+    the installed version will be included in printed information.
+*/
+void LoggingHandler::printPackageInformation(const PackagesList &matchedPackages, const LocalPackagesHash &installedPackages) const
+{
+    QDomDocument doc;
+    QDomElement root = doc.createElement(QLatin1String("availablepackages"));
+    doc.appendChild(root);
+    foreach (Package *package, matchedPackages) {
+        const QString name = package->data(scName).toString();
+        QDomElement update = doc.createElement(QLatin1String("package"));
+        update.setAttribute(QLatin1String("name"), name);
+        update.setAttribute(QLatin1String("displayname"), package->data(scDisplayName).toString());
+        update.setAttribute(QLatin1String("version"), package->data(scVersion).toString());
+        //Check if package already installed
+        if (installedPackages.contains(name))
+            update.setAttribute(QLatin1String("installedVersion"), installedPackages.value(name).version);
+        if (verboseLevel() == VerbosityLevel::Detailed) {
+            update.setAttribute(QLatin1String("description"), package->data(scDescription).toString());
+            update.setAttribute(QLatin1String("dependencies"), package->data(scDependencies).toString());
+            update.setAttribute(QLatin1String("autoDependencies"), package->data(scAutoDependOn).toString());
+            update.setAttribute(QLatin1String("virtual"), package->data(scVirtual).toString());
+            update.setAttribute(QLatin1String("forcedInstallation"), package->data(QLatin1String("ForcedInstallation")).toString());
+            update.setAttribute(QLatin1String("checkable"), package->data(scCheckable).toString());
+            update.setAttribute(QLatin1String("default"), package->data(scDefault).toString());
+            update.setAttribute(QLatin1String("essential"), package->data(scEssential).toString());
+            update.setAttribute(QLatin1String("forcedUpdate"), package->data(scForcedUpdate).toString());
+            update.setAttribute(QLatin1String("compressedsize"), package->data(QLatin1String("CompressedSize")).toString());
+            update.setAttribute(QLatin1String("uncompressedsize"), package->data(QLatin1String("UncompressedSize")).toString());
+            update.setAttribute(QLatin1String("releaseDate"), package->data(scReleaseDate).toString());
+            update.setAttribute(QLatin1String("downloadableArchives"), package->data(scDownloadableArchives).toString());
+            update.setAttribute(QLatin1String("licenses"), package->data(QLatin1String("Licenses")).toString());
+            update.setAttribute(QLatin1String("script"), package->data(scScript).toString());
+            update.setAttribute(QLatin1String("sortingPriority"), package->data(scSortingPriority).toString());
+            update.setAttribute(QLatin1String("replaces"), package->data(scReplaces).toString());
+            update.setAttribute(QLatin1String("requiresAdminRights"), package->data(scRequiresAdminRights).toString());
+        }
+        root.appendChild(update);
+    }
+    qCDebug(lcPackageInfo) << qPrintable(doc.toString(4));
+}
+
+/*!
+    \internal
+*/
+VerboseWriter::VerboseWriter()
+{
+    m_preFileBuffer.open(QIODevice::ReadWrite);
+    m_stream.setDevice(&m_preFileBuffer);
+    m_currentDateTimeAsString = QDateTime::currentDateTime().toString();
+}
+
+/*!
+    \internal
+*/
+VerboseWriter::~VerboseWriter()
+{
+    if (m_preFileBuffer.isOpen()) {
+        PlainVerboseWriterOutput output;
+        (void)flush(&output);
+    }
+}
+
+/*!
+    \internal
+*/
+bool VerboseWriter::flush(VerboseWriterOutput *output)
+{
+    m_stream.flush();
+    if (m_logFileName.isEmpty()) // binarycreator
+        return true;
+    if (!m_preFileBuffer.isOpen())
+        return true;
+    //if the installer installed nothing - there is no target directory - where the logfile can be saved
+    if (!QFileInfo(m_logFileName).absoluteDir().exists())
+        return true;
+
+    QString logInfo;
+    logInfo += QLatin1String("************************************* Invoked: ");
+    logInfo += m_currentDateTimeAsString;
+    logInfo += QLatin1String("\n");
+
+    QBuffer buffer;
+    buffer.open(QIODevice::WriteOnly);
+    buffer.write(logInfo.toLocal8Bit());
+    buffer.write(m_preFileBuffer.data());
+    buffer.close();
+
+    if (output->write(m_logFileName, QIODevice::ReadWrite | QIODevice::Append | QIODevice::Text, buffer.data())) {
+        m_preFileBuffer.close();
+        m_stream.setDevice(nullptr);
+        return true;
+    }
+    return false;
+}
+
+/*!
+    \internal
+*/
+void VerboseWriter::setFileName(const QString &fileName)
+{
+    m_logFileName = fileName;
+}
+
+Q_GLOBAL_STATIC(VerboseWriter, verboseWriter)
+
+/*!
+    \internal
+*/
+VerboseWriter *VerboseWriter::instance()
+{
+    return verboseWriter();
+}
+
+/*!
+    \internal
+*/
+void VerboseWriter::appendLine(const QString &msg)
+{
+    m_stream << msg << endl;
+}
+
+/*!
+    \internal
+*/
+VerboseWriterOutput::~VerboseWriterOutput()
+{
+}
+
+/*!
+    \internal
+*/
+bool PlainVerboseWriterOutput::write(const QString &fileName, QIODevice::OpenMode openMode, const QByteArray &data)
+{
+    QFile output(fileName);
+    if (output.open(openMode)) {
+        output.write(data);
+        setDefaultFilePermissions(&output, DefaultFilePermissions::NonExecutable);
+        return true;
+    }
+    return false;
+}
+
+/*!
+    \internal
+*/
+bool VerboseWriterAdminOutput::write(const QString &fileName, QIODevice::OpenMode openMode, const QByteArray &data)
+{
+    bool gainedAdminRights = false;
+
+    if (!RemoteClient::instance().isActive()) {
+        m_core->gainAdminRights();
+        gainedAdminRights = true;
+    }
+
+    RemoteFileEngine file;
+    file.setFileName(fileName);
+    if (file.open(openMode)) {
+        file.write(data.constData(), data.size());
+        file.close();
+        if (gainedAdminRights)
+            m_core->dropAdminRights();
+        return true;
+    }
+
+    if (gainedAdminRights)
+        m_core->dropAdminRights();
+
+    return false;
+}
+
+/*!
+    \internal
+
+    Increments verbosity \a level.
+*/
+LoggingHandler::VerbosityLevel &operator++(LoggingHandler::VerbosityLevel &level, int)
+{
+    const int i = static_cast<int>(level) + 1;
+    level = (i > LoggingHandler::VerbosityLevel::Maximum)
+        ? LoggingHandler::VerbosityLevel::Maximum
+        : static_cast<LoggingHandler::VerbosityLevel>(i);
+
+    return level;
+}
+
+/*!
+    \internal
+
+    Decrements verbosity \a level.
+*/
+LoggingHandler::VerbosityLevel &operator--(LoggingHandler::VerbosityLevel &level, int)
+{
+    const int i = static_cast<int>(level) - 1;
+    level = (i < LoggingHandler::VerbosityLevel::Minimum)
+        ? LoggingHandler::VerbosityLevel::Minimum
+        : static_cast<LoggingHandler::VerbosityLevel>(i);
+
+    return level;
+}
+
+} // namespace QInstaller
diff --git a/src/libs/installer/loggingutils.h b/src/libs/installer/loggingutils.h
new file mode 100644
index 000000000..a997a6d60
--- /dev/null
+++ b/src/libs/installer/loggingutils.h
@@ -0,0 +1,129 @@
+/**************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Installer Framework.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+**************************************************************************/
+
+#ifndef LOGGINGUTILS_H
+#define LOGGINGUTILS_H
+
+#include "component.h"
+
+#include <QObject>
+
+namespace QInstaller {
+
+class INSTALLER_EXPORT LoggingHandler
+{
+    Q_DISABLE_COPY(LoggingHandler)
+    Q_ENUMS(VerbosityLevel)
+
+public:
+    enum VerbosityLevel {
+        Silent = 0,
+        Normal = 1,
+        Detailed = 2,
+        Minimum = Silent,
+        Maximum = Detailed
+    };
+
+    static LoggingHandler &instance();
+    void messageHandler(QtMsgType type, const QMessageLogContext &context, const QString &msg);
+
+    void setVerbose(bool v);
+    bool isVerbose() const;
+    VerbosityLevel verboseLevel() const;
+    bool outputRedirected() const;
+
+    void printComponentInfo(const QList<Component *> components) const;
+    void printLocalPackageInformation(const QList<KDUpdater::LocalPackage> &packages) const;
+    void printPackageInformation(const PackagesList &matchedPackages, const LocalPackagesHash &installedPackages) const;
+
+    friend VerbosityLevel &operator++(VerbosityLevel &level, int);
+    friend VerbosityLevel &operator--(VerbosityLevel &level, int);
+
+private:
+    LoggingHandler();
+    ~LoggingHandler();
+
+    QString trimAndPrepend(QtMsgType type, const QString &msg) const;
+
+private:
+    VerbosityLevel m_verbLevel;
+    bool m_outputRedirected;
+};
+
+class INSTALLER_EXPORT VerboseWriterOutput
+{
+public:
+    virtual bool write(const QString &fileName, QIODevice::OpenMode openMode, const QByteArray &data) = 0;
+
+protected:
+    ~VerboseWriterOutput();
+};
+
+class INSTALLER_EXPORT PlainVerboseWriterOutput : public VerboseWriterOutput
+{
+public:
+    virtual bool write(const QString &fileName, QIODevice::OpenMode openMode, const QByteArray &data) override;
+};
+
+class INSTALLER_EXPORT VerboseWriterAdminOutput : public VerboseWriterOutput
+{
+public:
+    VerboseWriterAdminOutput(PackageManagerCore *core) : m_core(core) {}
+
+    virtual bool write(const QString &fileName, QIODevice::OpenMode openMode, const QByteArray &data) override;
+
+private:
+    PackageManagerCore *m_core;
+};
+
+class INSTALLER_EXPORT VerboseWriter
+{
+public:
+    VerboseWriter();
+    ~VerboseWriter();
+
+    static VerboseWriter *instance();
+
+    bool flush(VerboseWriterOutput *output);
+
+    void appendLine(const QString &msg);
+    void setFileName(const QString &fileName);
+
+private:
+    QTextStream m_stream;
+    QBuffer m_preFileBuffer;
+    QString m_logFileName;
+    QString m_currentDateTimeAsString;
+};
+
+LoggingHandler::VerbosityLevel &operator++(LoggingHandler::VerbosityLevel &level, int);
+LoggingHandler::VerbosityLevel &operator--(LoggingHandler::VerbosityLevel &level, int);
+
+} // namespace QInstaller
+
+#endif // LOGGINGUTILS_H
diff --git a/src/libs/installer/packagemanagercore.cpp b/src/libs/installer/packagemanagercore.cpp
index ca128c6ea..4a0d2c191 100644
--- a/src/libs/installer/packagemanagercore.cpp
+++ b/src/libs/installer/packagemanagercore.cpp
@@ -1,6 +1,6 @@
 /**************************************************************************
 **
-** Copyright (C) 2020 The Qt Company Ltd.
+** Copyright (C) 2021 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Installer Framework.
@@ -45,7 +45,7 @@
 #include "settings.h"
 #include "installercalculator.h"
 #include "uninstallercalculator.h"
-#include "printoutput.h"
+#include "loggingutils.h"
 
 #include <productkeycheck.h>
 
@@ -1202,40 +1202,6 @@ PackageManagerCore::PackageManagerCore(qint64 magicmaker, const QList<OperationB
             ProgressCoordinator::instance(), &ProgressCoordinator::printProgressMessage);
 }
 
-class VerboseWriterAdminOutput : public VerboseWriterOutput
-{
-public:
-    VerboseWriterAdminOutput(PackageManagerCore *core) : m_core(core) {}
-
-    virtual bool write(const QString &fileName, QIODevice::OpenMode openMode, const QByteArray &data) Q_DECL_OVERRIDE
-    {
-        bool gainedAdminRights = false;
-
-        if (!RemoteClient::instance().isActive()) {
-            m_core->gainAdminRights();
-            gainedAdminRights = true;
-        }
-
-        RemoteFileEngine file;
-        file.setFileName(fileName);
-        if (file.open(openMode)) {
-            file.write(data.constData(), data.size());
-            file.close();
-            if (gainedAdminRights)
-                m_core->dropAdminRights();
-            return true;
-        }
-
-        if (gainedAdminRights)
-            m_core->dropAdminRights();
-
-        return false;
-    }
-
-private:
-    PackageManagerCore *m_core;
-};
-
 /*!
     Destroys the instance.
 */
@@ -2225,7 +2191,7 @@ void PackageManagerCore::listAvailablePackages(const QString &regexp)
     if (matchedPackages.count() == 0)
         qCDebug(QInstaller::lcInstallerInstallLog) << "No matching packages found.";
     else
-        QInstaller::printPackageInformation(matchedPackages, localInstalledPackages());
+        LoggingHandler::instance().printPackageInformation(matchedPackages, localInstalledPackages());
 }
 
 bool PackageManagerCore::componentUninstallableFromCommandLine(const QString &componentName)
@@ -2321,7 +2287,7 @@ void PackageManagerCore::listInstalledPackages(const QString &regexp)
         if (re.match(package.name).hasMatch())
             packages.append(package);
     }
-    QInstaller::printLocalPackageInformation(packages);
+    LoggingHandler::instance().printLocalPackageInformation(packages);
 }
 
 /*!
@@ -3177,15 +3143,7 @@ bool PackageManagerCore::containsValue(const QString &key) const
 */
 bool PackageManagerCore::isVerbose() const
 {
-    return QInstaller::isVerbose();
-}
-
-/*!
-    Returns verbose level.
-*/
-VerbosityLevel PackageManagerCore::verboseLevel() const
-{
-    return QInstaller::verboseLevel();
+    return LoggingHandler::instance().isVerbose();
 }
 
 /*!
@@ -3194,7 +3152,7 @@ VerbosityLevel PackageManagerCore::verboseLevel() const
 */
 void PackageManagerCore::setVerbose(bool on)
 {
-    QInstaller::setVerbose(on);
+    LoggingHandler::instance().setVerbose(on);
 }
 
 PackageManagerCore::Status PackageManagerCore::status() const
@@ -3562,7 +3520,7 @@ bool PackageManagerCore::updateComponentData(struct Data &data, Component *compo
 
         component->setUninstalled();
         const QString localPath = component->localTempPath();
-        if (verboseLevel() == VerbosityLevel::Detailed) {
+        if (LoggingHandler::instance().verboseLevel() == LoggingHandler::Detailed) {
             static QString lastLocalPath;
             if (lastLocalPath != localPath)
                 qCDebug(QInstaller::lcDeveloperBuild()) << "Url is:" << localPath;
diff --git a/src/libs/installer/packagemanagercore.h b/src/libs/installer/packagemanagercore.h
index 70ec83f15..b83d8f05a 100644
--- a/src/libs/installer/packagemanagercore.h
+++ b/src/libs/installer/packagemanagercore.h
@@ -1,6 +1,6 @@
 /**************************************************************************
 **
-** Copyright (C) 2020 The Qt Company Ltd.
+** Copyright (C) 2021 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Installer Framework.
@@ -278,8 +278,6 @@ public:
     bool isVerbose() const;
     void setVerbose(bool on);
 
-    VerbosityLevel verboseLevel() const;
-
     Q_INVOKABLE bool gainAdminRights();
     Q_INVOKABLE void dropAdminRights();
 
diff --git a/src/libs/installer/packagemanagercore_p.cpp b/src/libs/installer/packagemanagercore_p.cpp
index 7f4330ca8..274ea017b 100644
--- a/src/libs/installer/packagemanagercore_p.cpp
+++ b/src/libs/installer/packagemanagercore_p.cpp
@@ -49,6 +49,7 @@
 #include "componentchecker.h"
 #include "globals.h"
 #include "binarycreator.h"
+#include "loggingutils.h"
 
 #include "selfrestarter.h"
 #include "filedownloaderfactory.h"
@@ -465,7 +466,7 @@ bool PackageManagerCorePrivate::buildComponentTree(QHash<QString, Component*> &c
 
         restoreCheckState();
 
-        if (m_core->verboseLevel() == VerbosityLevel::Detailed) {
+        if (LoggingHandler::instance().verboseLevel() == LoggingHandler::Detailed) {
             foreach (QInstaller::Component *component, components) {
                 const QStringList warnings = ComponentChecker::checkComponent(component);
                 foreach (const QString &warning, warnings)
diff --git a/src/libs/installer/packagemanagergui.cpp b/src/libs/installer/packagemanagergui.cpp
index beb8603a4..e9f3a42fa 100644
--- a/src/libs/installer/packagemanagergui.cpp
+++ b/src/libs/installer/packagemanagergui.cpp
@@ -41,6 +41,7 @@
 #include "productkeycheck.h"
 #include "repositorycategory.h"
 #include "componentselectionpage_p.h"
+#include "loggingutils.h"
 
 #include "sysinfo.h"
 #include "globals.h"
@@ -2578,7 +2579,7 @@ void ReadyForInstallationPage::entering()
     QString htmlOutput;
     bool componentsOk = packageManagerCore()->calculateComponents(&htmlOutput);
     m_taskDetailsBrowser->setHtml(htmlOutput);
-    m_taskDetailsBrowser->setVisible(!componentsOk || isVerbose());
+    m_taskDetailsBrowser->setVisible(!componentsOk || LoggingHandler::instance().isVerbose());
     setComplete(componentsOk);
 
     QString spaceInfo;
@@ -2719,7 +2720,7 @@ void PerformInstallationPage::entering()
     if (packageManagerCore()->settings().productImages().count() > 1)
         m_imageChangeTimer.start();
 
-    if (isVerbose()) {
+    if (LoggingHandler::instance().isVerbose()) {
         m_performInstallationForm->toggleDetails();
     }
     if (packageManagerCore()->isUninstaller()) {
diff --git a/src/libs/installer/printoutput.cpp b/src/libs/installer/printoutput.cpp
deleted file mode 100644
index 27281aaf0..000000000
--- a/src/libs/installer/printoutput.cpp
+++ /dev/null
@@ -1,123 +0,0 @@
-/**************************************************************************
-**
-** Copyright (C) 2020 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of the Qt Installer Framework.
-**
-** $QT_BEGIN_LICENSE:GPL-EXCEPT$
-** Commercial License Usage
-** Licensees holding valid commercial Qt licenses may use this file in
-** accordance with the commercial license agreement provided with the
-** Software or, alternatively, in accordance with the terms contained in
-** a written agreement between you and The Qt Company. For licensing terms
-** and conditions see https://www.qt.io/terms-conditions. For further
-** information use the contact form at https://www.qt.io/contact-us.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 3 as published by the Free Software
-** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-3.0.html.
-**
-** $QT_END_LICENSE$
-**
-**************************************************************************/
-
-#include "printoutput.h"
-
-#include "component.h"
-#include "localpackagehub.h"
-#include "globals.h"
-
-#include <iostream>
-#include <QDomDocument>
-
-namespace QInstaller
-{
-
-void printComponentInfo(const QList<Component *> components)
-{
-    QDomDocument doc;
-    QDomElement root = doc.createElement(QLatin1String("updates"));
-    doc.appendChild(root);
-
-    foreach (Component *component, components) {
-        QDomElement update = doc.createElement(QLatin1String("update"));
-        update.setAttribute(QLatin1String("name"), component->value(scDisplayName));
-        update.setAttribute(QLatin1String("version"), component->value(scVersion));
-        update.setAttribute(QLatin1String("size"), component->value(scUncompressedSize));
-        update.setAttribute(QLatin1String("id"), component->value(scName));
-        root.appendChild(update);
-    }
-    qCDebug(lcPackageInfo) << qPrintable(doc.toString(4));
-}
-
-void printLocalPackageInformation(const QList<KDUpdater::LocalPackage> &packages)
-{
-    QDomDocument doc;
-    QDomElement root = doc.createElement(QLatin1String("localpackages"));
-    doc.appendChild(root);
-    foreach (KDUpdater::LocalPackage package, packages) {
-        QDomElement update = doc.createElement(QLatin1String("package"));
-        update.setAttribute(QLatin1String("name"), package.name);
-        update.setAttribute(QLatin1String("displayname"), package.title);
-        update.setAttribute(QLatin1String("version"), package.version);
-        if (verboseLevel() == VerbosityLevel::Detailed) {
-            update.setAttribute(QLatin1String("description"), package.description);
-            update.setAttribute(QLatin1String("dependencies"), package.dependencies.join(QLatin1Char(',')));
-            update.setAttribute(QLatin1String("autoDependencies"), package.autoDependencies.join(QLatin1Char(',')));
-            update.setAttribute(QLatin1String("virtual"), package.virtualComp);
-            update.setAttribute(QLatin1String("forcedInstallation"), package.forcedInstallation);
-            update.setAttribute(QLatin1String("checkable"), package.checkable);
-            update.setAttribute(QLatin1String("uncompressedSize"), package.uncompressedSize);
-            update.setAttribute(QLatin1String("installDate"), package.installDate.toString());
-            update.setAttribute(QLatin1String("lastUpdateDate"), package.lastUpdateDate.toString());
-        }
-        root.appendChild(update);
-    }
-    qCDebug(lcPackageInfo) << qPrintable(doc.toString(4));
-}
-
-void printPackageInformation(const PackagesList &matchedPackages, const LocalPackagesHash &installedPackages)
-{
-    QDomDocument doc;
-    QDomElement root = doc.createElement(QLatin1String("availablepackages"));
-    doc.appendChild(root);
-    foreach (Package *package, matchedPackages) {
-        const QString name = package->data(scName).toString();
-        QDomElement update = doc.createElement(QLatin1String("package"));
-        update.setAttribute(QLatin1String("name"), name);
-        update.setAttribute(QLatin1String("displayname"), package->data(scDisplayName).toString());
-        update.setAttribute(QLatin1String("version"), package->data(scVersion).toString());
-        //Check if package already installed
-        if (installedPackages.contains(name))
-            update.setAttribute(QLatin1String("installedVersion"), installedPackages.value(name).version);
-        if (verboseLevel() == VerbosityLevel::Detailed) {
-            update.setAttribute(QLatin1String("description"), package->data(scDescription).toString());
-            update.setAttribute(QLatin1String("dependencies"), package->data(scDependencies).toString());
-            update.setAttribute(QLatin1String("autoDependencies"), package->data(scAutoDependOn).toString());
-            update.setAttribute(QLatin1String("virtual"), package->data(scVirtual).toString());
-            update.setAttribute(QLatin1String("forcedInstallation"), package->data(QLatin1String("ForcedInstallation")).toString());
-            update.setAttribute(QLatin1String("checkable"), package->data(scCheckable).toString());
-            update.setAttribute(QLatin1String("default"), package->data(scDefault).toString());
-            update.setAttribute(QLatin1String("essential"), package->data(scEssential).toString());
-            update.setAttribute(QLatin1String("forcedUpdate"), package->data(scForcedUpdate).toString());
-            update.setAttribute(QLatin1String("compressedsize"), package->data(QLatin1String("CompressedSize")).toString());
-            update.setAttribute(QLatin1String("uncompressedsize"), package->data(QLatin1String("UncompressedSize")).toString());
-            update.setAttribute(QLatin1String("releaseDate"), package->data(scReleaseDate).toString());
-            update.setAttribute(QLatin1String("downloadableArchives"), package->data(scDownloadableArchives).toString());
-            update.setAttribute(QLatin1String("licenses"), package->data(QLatin1String("Licenses")).toString());
-            update.setAttribute(QLatin1String("script"), package->data(scScript).toString());
-            update.setAttribute(QLatin1String("sortingPriority"), package->data(scSortingPriority).toString());
-            update.setAttribute(QLatin1String("replaces"), package->data(scReplaces).toString());
-            update.setAttribute(QLatin1String("requiresAdminRights"), package->data(scRequiresAdminRights).toString());
-        }
-        root.appendChild(update);
-    }
-    qCDebug(lcPackageInfo) << qPrintable(doc.toString(4));
-}
-} // namespace QInstaller
-
diff --git a/src/libs/installer/printoutput.h b/src/libs/installer/printoutput.h
deleted file mode 100644
index b1767830a..000000000
--- a/src/libs/installer/printoutput.h
+++ /dev/null
@@ -1,42 +0,0 @@
-/**************************************************************************
-**
-** Copyright (C) 2020 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of the Qt Installer Framework.
-**
-** $QT_BEGIN_LICENSE:GPL-EXCEPT$
-** Commercial License Usage
-** Licensees holding valid commercial Qt licenses may use this file in
-** accordance with the commercial license agreement provided with the
-** Software or, alternatively, in accordance with the terms contained in
-** a written agreement between you and The Qt Company. For licensing terms
-** and conditions see https://www.qt.io/terms-conditions. For further
-** information use the contact form at https://www.qt.io/contact-us.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 3 as published by the Free Software
-** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-3.0.html.
-**
-** $QT_END_LICENSE$
-**
-**************************************************************************/
-
-#ifndef PRINTOUTPUT_H
-#define PRINTOUTPUT_H
-
-#include "component.h"
-
-#include <QObject>
-
-namespace QInstaller {
-    void INSTALLER_EXPORT printComponentInfo(const QList<Component *> components);
-    void INSTALLER_EXPORT printLocalPackageInformation(const QList<KDUpdater::LocalPackage> &packages);
-    void INSTALLER_EXPORT printPackageInformation(const PackagesList &matchedPackages, const LocalPackagesHash &installedPackages);
-}
-
-#endif // PRINTOUTPUT_H
diff --git a/src/libs/installer/progresscoordinator.cpp b/src/libs/installer/progresscoordinator.cpp
index 7af24cb77..01b92bff8 100644
--- a/src/libs/installer/progresscoordinator.cpp
+++ b/src/libs/installer/progresscoordinator.cpp
@@ -1,6 +1,6 @@
 /**************************************************************************
 **
-** Copyright (C) 2020 The Qt Company Ltd.
+** Copyright (C) 2021 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Installer Framework.
@@ -35,6 +35,7 @@
 
 #include "globals.h"
 #include "utils.h"
+#include "loggingutils.h"
 
 using namespace QInstaller;
 
@@ -312,7 +313,7 @@ void ProgressCoordinator::emitDownloadStatus(const QString &status)
 
 void ProgressCoordinator::printProgressPercentage(int progress)
 {
-    if (!isVerbose())
+    if (!LoggingHandler::instance().isVerbose())
         return;
 
     Q_ASSERT(m_progressSpinner->currentIndex < m_progressSpinner->spinnerChars.size());
diff --git a/src/libs/installer/utils.cpp b/src/libs/installer/utils.cpp
index 76ce9a938..59be2171b 100644
--- a/src/libs/installer/utils.cpp
+++ b/src/libs/installer/utils.cpp
@@ -1,6 +1,6 @@
 /**************************************************************************
 **
-** Copyright (C) 2020 The Qt Company Ltd.
+** Copyright (C) 2021 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Installer Framework.
@@ -52,37 +52,6 @@
 #endif
 
 /*!
-    \inmodule QtInstallerFramework
-    \class QInstaller::PlainVerboseWriterOutput
-    \internal
-*/
-
-/*!
-    \inmodule QtInstallerFramework
-    \class QInstaller::VerboseWriterOutput
-    \internal
-*/
-
-/*!
-    \inmodule QtInstallerFramework
-    \class QInstaller::VerboseWriter
-    \internal
-*/
-
-/*!
-    \enum QInstaller::VerbosityLevel
-    \brief This enum holds the possible levels of output verbosity.
-
-    \value Silent
-    \value Normal
-    \value Detailed
-    \value Minimum
-           Minimum possible verbosity level. Synonym for \c VerbosityLevel::Silent.
-    \value Maximum
-           Maximum possible verbosity level. Synonym for \c VerbosityLevel::Detailed.
-*/
-
-/*!
     \internal
 */
 void QInstaller::uiDetachedWait(int ms)
@@ -164,37 +133,6 @@ QStringList QInstaller::localeCandidates(const QString &locale_)
     return candidates;
 }
 
-
-static QInstaller::VerbosityLevel verbLevel = QInstaller::VerbosityLevel::Silent;
-
-/*!
-    Sets to verbose output if \a v is set to \c true. Calling this multiple
-    times increases or decreases the verbosity level accordingly.
-*/
-void QInstaller::setVerbose(bool v)
-{
-    if (v)
-        verbLevel++;
-    else
-        verbLevel--;
-}
-
-/*!
-    Returns \c true if the installer is set to verbose output.
-*/
-bool QInstaller::isVerbose()
-{
-    return verbLevel != VerbosityLevel::Silent;
-}
-
-/*!
-    Returns the current verbosity level.
-*/
-QInstaller::VerbosityLevel QInstaller::verboseLevel()
-{
-    return verbLevel;
-}
-
 /*!
     Returns a list of mutually exclusive options passed to the \a parser, if there is
     at least one mutually exclusive pair of options set. Otherwise returns an empty
@@ -295,84 +233,6 @@ QString QInstaller::replaceWindowsEnvironmentVariables(const QString &str)
     return res;
 }
 
-QInstaller::VerboseWriter::VerboseWriter()
-{
-    preFileBuffer.open(QIODevice::ReadWrite);
-    stream.setDevice(&preFileBuffer);
-    currentDateTimeAsString = QDateTime::currentDateTime().toString();
-}
-
-QInstaller::VerboseWriter::~VerboseWriter()
-{
-    if (preFileBuffer.isOpen()) {
-        PlainVerboseWriterOutput output;
-        (void)flush(&output);
-    }
-}
-
-bool QInstaller::VerboseWriter::flush(VerboseWriterOutput *output)
-{
-    stream.flush();
-    if (logFileName.isEmpty()) // binarycreator
-        return true;
-    if (!preFileBuffer.isOpen())
-        return true;
-    //if the installer installed nothing - there is no target directory - where the logfile can be saved
-    if (!QFileInfo(logFileName).absoluteDir().exists())
-        return true;
-
-    QString logInfo;
-    logInfo += QLatin1String("************************************* Invoked: ");
-    logInfo += currentDateTimeAsString;
-    logInfo += QLatin1String("\n");
-
-    QBuffer buffer;
-    buffer.open(QIODevice::WriteOnly);
-    buffer.write(logInfo.toLocal8Bit());
-    buffer.write(preFileBuffer.data());
-    buffer.close();
-
-    if (output->write(logFileName, QIODevice::ReadWrite | QIODevice::Append | QIODevice::Text, buffer.data())) {
-        preFileBuffer.close();
-        stream.setDevice(nullptr);
-        return true;
-    }
-    return false;
-}
-
-void QInstaller::VerboseWriter::setFileName(const QString &fileName)
-{
-    logFileName = fileName;
-}
-
-
-Q_GLOBAL_STATIC(QInstaller::VerboseWriter, verboseWriter)
-
-QInstaller::VerboseWriter *QInstaller::VerboseWriter::instance()
-{
-    return verboseWriter();
-}
-
-void QInstaller::VerboseWriter::appendLine(const QString &msg)
-{
-    stream << msg << endl;
-}
-
-QInstaller::VerboseWriterOutput::~VerboseWriterOutput()
-{
-}
-
-bool QInstaller::PlainVerboseWriterOutput::write(const QString &fileName, QIODevice::OpenMode openMode, const QByteArray &data)
-{
-    QFile output(fileName);
-    if (output.open(openMode)) {
-        output.write(data);
-        setDefaultFilePermissions(&output, DefaultFilePermissions::NonExecutable);
-        return true;
-    }
-    return false;
-}
-
 #ifdef Q_OS_WIN
 // taken from qcoreapplication_p.h
 template<typename Char>
@@ -542,33 +402,3 @@ QString QInstaller::windowsErrorString(int errorCode)
 }
 
 #endif
-
-/*!
-    \internal
-
-    Increments verbosity \a level.
-*/
-QInstaller::VerbosityLevel &QInstaller::operator++(QInstaller::VerbosityLevel &level, int)
-{
-    const int i = static_cast<int>(level) + 1;
-    level = (i > VerbosityLevel::Maximum)
-        ? VerbosityLevel::Maximum
-        : static_cast<VerbosityLevel>(i);
-
-    return level;
-}
-
-/*!
-    \internal
-
-    Decrements verbosity \a level.
-*/
-QInstaller::VerbosityLevel &QInstaller::operator--(QInstaller::VerbosityLevel &level, int)
-{
-    const int i = static_cast<int>(level) - 1;
-    level = (i < VerbosityLevel::Minimum)
-        ? VerbosityLevel::Minimum
-        : static_cast<VerbosityLevel>(i);
-
-    return level;
-}
diff --git a/src/libs/installer/utils.h b/src/libs/installer/utils.h
index 0c32c1672..a22acd879 100644
--- a/src/libs/installer/utils.h
+++ b/src/libs/installer/utils.h
@@ -1,6 +1,6 @@
 /**************************************************************************
 **
-** Copyright (C) 2020 The Qt Company Ltd.
+** Copyright (C) 2021 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Installer Framework.
@@ -46,14 +46,6 @@ QT_END_NAMESPACE
 
 namespace QInstaller {
 
-    enum INSTALLER_EXPORT VerbosityLevel {
-        Silent = 0,
-        Normal = 1,
-        Detailed = 2,
-        Minimum = Silent,
-        Maximum = Detailed
-    };
-
     void INSTALLER_EXPORT uiDetachedWait(int ms);
     bool INSTALLER_EXPORT startDetached(const QString &program, const QStringList &arguments,
         const QString &workingDirectory, qint64 *pid = 0);
@@ -72,51 +64,9 @@ namespace QInstaller {
 
     QStringList INSTALLER_EXPORT localeCandidates(const QString &locale);
 
-    void INSTALLER_EXPORT setVerbose(bool v);
-    bool INSTALLER_EXPORT isVerbose();
-    VerbosityLevel INSTALLER_EXPORT verboseLevel();
-
     QStringList INSTALLER_EXPORT checkMutualOptions(CommandLineParser &parser, const QStringList &options);
 
     INSTALLER_EXPORT std::ostream& operator<<(std::ostream &os, const QString &string);
-
-    class INSTALLER_EXPORT VerboseWriterOutput
-    {
-    public:
-        virtual bool write(const QString &fileName, QIODevice::OpenMode openMode, const QByteArray &data) = 0;
-
-    protected:
-        ~VerboseWriterOutput();
-    };
-
-    class INSTALLER_EXPORT PlainVerboseWriterOutput : public VerboseWriterOutput
-    {
-    public:
-        virtual bool write(const QString &fileName, QIODevice::OpenMode openMode, const QByteArray &data);
-    };
-
-    class INSTALLER_EXPORT VerboseWriter
-    {
-    public:
-        VerboseWriter();
-        ~VerboseWriter();
-
-        static VerboseWriter *instance();
-
-        bool flush(VerboseWriterOutput *output);
-
-        void appendLine(const QString &msg);
-        void setFileName(const QString &fileName);
-
-    private:
-        QTextStream stream;
-        QBuffer preFileBuffer;
-        QString logFileName;
-        QString currentDateTimeAsString;
-    };
-
-    VerbosityLevel &operator++(VerbosityLevel &level, int);
-    VerbosityLevel &operator--(VerbosityLevel &level, int);
 }
 
 #endif // QINSTALLER_UTILS_H
diff --git a/src/libs/kdtools/filedownloader.cpp b/src/libs/kdtools/filedownloader.cpp
index ea8fdd23b..4cccfd9ca 100644
--- a/src/libs/kdtools/filedownloader.cpp
+++ b/src/libs/kdtools/filedownloader.cpp
@@ -32,6 +32,7 @@
 
 #include "fileutils.h"
 #include "utils.h"
+#include "loggingutils.h"
 
 #include <QDialog>
 #include <QDir>
@@ -1401,7 +1402,8 @@ void KDUpdater::HttpDownloader::httpReqFinished()
         const QUrl url = d->http->url();
         // Only print host information when the logging category is enabled
         // and output verbosity is set above standard level.
-        if (url.isValid() && QInstaller::lcServer().isDebugEnabled() && verboseLevel() == VerbosityLevel::Detailed) {
+        if (url.isValid() && QInstaller::lcServer().isDebugEnabled()
+                && LoggingHandler::instance().verboseLevel() == LoggingHandler::Detailed) {
             const QFileInfo fi(d->http->url().toString());
             if (fi.suffix() != QLatin1String("sha1")){
                 const QString hostName = url.host();
diff --git a/src/sdk/commandlineinterface.cpp b/src/sdk/commandlineinterface.cpp
index 7bb76d2af..69aa36c43 100644
--- a/src/sdk/commandlineinterface.cpp
+++ b/src/sdk/commandlineinterface.cpp
@@ -1,6 +1,6 @@
 /**************************************************************************
 **
-** Copyright (C) 2020 The Qt Company Ltd.
+** Copyright (C) 2021 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Installer Framework.
@@ -34,7 +34,7 @@
 #include <globals.h>
 #include <productkeycheck.h>
 #include <errors.h>
-#include <printoutput.h>
+#include <loggingutils.h>
 
 #include <QDir>
 
@@ -101,7 +101,7 @@ int CommandLineInterface::checkUpdates()
         qCWarning(QInstaller::lcInstallerInstallLog) << "There are currently no updates available.";
         return EXIT_SUCCESS;
     }
-    QInstaller::printComponentInfo(components);
+    QInstaller::LoggingHandler::instance().printComponentInfo(components);
     return EXIT_SUCCESS;
 }
 
diff --git a/src/sdk/main.cpp b/src/sdk/main.cpp
index 076458173..a2eb22189 100644
--- a/src/sdk/main.cpp
+++ b/src/sdk/main.cpp
@@ -1,6 +1,6 @@
 /**************************************************************************
 **
-** Copyright (C) 2020 The Qt Company Ltd.
+** Copyright (C) 2021 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Installer Framework.
@@ -36,6 +36,7 @@
 #include <selfrestarter.h>
 #include <remoteserver.h>
 #include <utils.h>
+#include <loggingutils.h>
 
 #include <QCommandLineParser>
 #include <QDateTime>
@@ -212,14 +213,14 @@ int main(int argc, char *argv[])
         foreach (QString value, optionNames) {
             if (value == CommandLineOptions::scVerboseShort
                     || value == CommandLineOptions::scVerboseLong) {
-                QInstaller::setVerbose(true);
+                QInstaller::LoggingHandler::instance().setVerbose(true);
             }
         }
 
         foreach (const QString &option, CommandLineOptions::scCommandLineInterfaceOptions) {
             bool setVerbose = parser.positionalArguments().contains(option);
             if (setVerbose) {
-                QInstaller::setVerbose(setVerbose);
+                QInstaller::LoggingHandler::instance().setVerbose(setVerbose);
                 break;
             }
         }
@@ -267,7 +268,7 @@ int main(int argc, char *argv[])
                 || parser.positionalArguments().contains(CommandLineOptions::scCreateOfflineLong)) {
             return CommandLineInterface(argc, argv).createOfflineInstaller();
         }
-        if (QInstaller::isVerbose()) {
+        if (QInstaller::LoggingHandler::instance().isVerbose()) {
             std::cout << VERSION << std::endl << BUILDDATE << std::endl << SHA << std::endl;
         } else {
 #ifdef Q_OS_WIN
diff --git a/src/sdk/sdkapp.h b/src/sdk/sdkapp.h
index 79c112642..ad40e0a42 100644
--- a/src/sdk/sdkapp.h
+++ b/src/sdk/sdkapp.h
@@ -1,6 +1,6 @@
 /**************************************************************************
 **
-** Copyright (C) 2020 The Qt Company Ltd.
+** Copyright (C) 2021 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Installer Framework.
@@ -46,6 +46,7 @@
 #include <runoncechecker.h>
 #include <globals.h>
 #include <errors.h>
+#include <loggingutils.h>
 
 #include <QApplication>
 #include <QDir>
@@ -164,7 +165,7 @@ public:
                                         "ifw.package.* = true\n");
         }
 
-        if (QInstaller::verboseLevel() == QInstaller::VerbosityLevel::Detailed) {
+        if (QInstaller::LoggingHandler::instance().verboseLevel() == QInstaller::LoggingHandler::Detailed) {
             loggingRules += QLatin1String("\nifw.developer.build = true\n"
                                           "ifw.package.* = true\n");
         }
diff --git a/tools/binarycreator/main.cpp b/tools/binarycreator/main.cpp
index b5a0ae4f7..c28a2ebb3 100644
--- a/tools/binarycreator/main.cpp
+++ b/tools/binarycreator/main.cpp
@@ -1,6 +1,6 @@
 /**************************************************************************
 **
-** Copyright (C) 2020 The Qt Company Ltd.
+** Copyright (C) 2021 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Installer Framework.
@@ -29,6 +29,7 @@
 #include <binarycreator.h>
 #include <init.h>
 #include <utils.h>
+#include <loggingutils.h>
 
 #include <QtCore/QDebug>
 
@@ -152,7 +153,7 @@ int main(int argc, char **argv)
             parsedArgs.ftype = QInstallerTools::Include;
         }
         else if (*it == QLatin1String("-v") || *it == QLatin1String("--verbose")) {
-            QInstaller::setVerbose(true);
+            LoggingHandler::instance().setVerbose(true);
         } else if (*it == QLatin1String("-n") || *it == QLatin1String("--online-only")) {
             parsedArgs.onlineOnly = true;
         } else if (*it == QLatin1String("-f") || *it == QLatin1String("--offline-only")) {
diff --git a/tools/devtool/main.cpp b/tools/devtool/main.cpp
index 208ef148e..52db7d8b3 100644
--- a/tools/devtool/main.cpp
+++ b/tools/devtool/main.cpp
@@ -1,6 +1,6 @@
 /**************************************************************************
 **
-** Copyright (C) 2017 The Qt Company Ltd.
+** Copyright (C) 2021 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Installer Framework.
@@ -37,6 +37,7 @@
 #include <fileutils.h>
 #include <init.h>
 #include <utils.h>
+#include <loggingutils.h>
 
 #include <QCoreApplication>
 #include <QCommandLineParser>
@@ -161,7 +162,7 @@ int main(int argc, char *argv[])
         return fail(QString::fromLatin1("\"%1\" is not a devtool command.").arg(command));
 
     QInstaller::init();
-    QInstaller::setVerbose(parser.isSet(verbose));
+    QInstaller::LoggingHandler::instance().setVerbose(parser.isSet(verbose));
 
     QString bundlePath;
     QString path = QFileInfo(arguments.first()).absoluteFilePath();
diff --git a/tools/repogen/repogen.cpp b/tools/repogen/repogen.cpp
index 10aa0370b..a88867e92 100644
--- a/tools/repogen/repogen.cpp
+++ b/tools/repogen/repogen.cpp
@@ -1,6 +1,6 @@
 /**************************************************************************
 **
-** Copyright (C) 2020 The Qt Company Ltd.
+** Copyright (C) 2021 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Installer Framework.
@@ -33,6 +33,7 @@
 #include <updater.h>
 #include <settings.h>
 #include <utils.h>
+#include <loggingutils.h>
 #include <lib7z_facade.h>
 
 #include <QDomDocument>
@@ -112,7 +113,7 @@ int main(int argc, char** argv)
         while (!args.isEmpty() && args.first().startsWith(QLatin1Char('-'))) {
             if (args.first() == QLatin1String("--verbose") || args.first() == QLatin1String("-v")) {
                 args.removeFirst();
-                setVerbose(true);
+                LoggingHandler::instance().setVerbose(true);
             } else if (args.first() == QLatin1String("--exclude") || args.first() == QLatin1String("-e")) {
                 args.removeFirst();
                 if (!filteredPackages.isEmpty()) {