glogg/src/crawlerwidget.cpp

/*
 * Copyright (C) 2009, 2010, 2011, 2012, 2013, 2014, 2015 Nicolas Bonnefon and other contributors
 *
 * This file is part of glogg.
 *
 * glogg is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * glogg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with glogg.  If not, see <http://www.gnu.org/licenses/>.
 */

// This file implements the CrawlerWidget class.
// It is responsible for creating and managing the two views and all
// the UI elements.  It implements the connection between the UI elements.
// It also interacts with the sets of data (full and filtered).

#include "log.h"

#include <cassert>

#include <Qt>
#include <QApplication>
#include <QFile>
#include <QLineEdit>
#include <QFileInfo>
#include <QStandardItemModel>
#include <QHeaderView>
#include <QListView>

#include "crawlerwidget.h"

#include "quickfindpattern.h"
#include "overview.h"
#include "infoline.h"
#include "savedsearches.h"
#include "quickfindwidget.h"
#include "persistentinfo.h"
#include "configuration.h"

// Palette for error signaling (yellow background)
const QPalette CrawlerWidget::errorPalette( QColor( "yellow" ) );

// Implementation of the view context for the CrawlerWidget
class CrawlerWidgetContext : public ViewContextInterface {
  public:
    // Construct from the stored string representation
    CrawlerWidgetContext( const char* string );
    // Construct from the value passsed
    CrawlerWidgetContext( QList<int> sizes,
           bool ignore_case,
           bool auto_refresh )
        : sizes_( sizes ),
          ignore_case_( ignore_case ),
          auto_refresh_( auto_refresh ) {}

    // Implementation of the ViewContextInterface function
    std::string toString() const;

    // Access the Qt sizes array for the QSplitter
    QList<int> sizes() const { return sizes_; }

    bool ignoreCase() const { return ignore_case_; }
    bool autoRefresh() const { return auto_refresh_; }

  private:
    QList<int> sizes_;

    bool ignore_case_;
    bool auto_refresh_;
};

// Constructor only does trivial construction. The real work is done once
// the data is attached.
CrawlerWidget::CrawlerWidget( QWidget *parent )
        : QSplitter( parent ), overview_()
{
    logData_         = nullptr;
    logFilteredData_ = nullptr;

    quickFindPattern_ = nullptr;
    savedSearches_   = nullptr;
    qfSavedFocus_    = nullptr;

    // Until we have received confirmation loading is finished, we
    // should consider we are loading something.
    loadingInProgress_ = true;
    // and it's the first time
    firstLoadDone_     = false;
    nbMatches_         = 0;
    dataStatus_        = DataStatus::OLD_DATA;

    currentLineNumber_ = 0;
}

// The top line is first one on the main display
int CrawlerWidget::getTopLine() const
{
    return logMainView->getTopLine();
}

QString CrawlerWidget::getSelectedText() const
{
    if ( filteredView->hasFocus() )
        return filteredView->getSelection();
    else
        return logMainView->getSelection();
}

void CrawlerWidget::selectAll()
{
    activeView()->selectAll();
}

CrawlerWidget::Encoding CrawlerWidget::encodingSetting() const
{
    return encodingSetting_;
}

bool CrawlerWidget::isFollowEnabled() const
{
    return logMainView->isFollowEnabled();
}

QString CrawlerWidget::encodingText() const
{
    return encoding_text_;
}

// Return a pointer to the view in which we should do the QuickFind
SearchableWidgetInterface* CrawlerWidget::doGetActiveSearchable() const
{
    return activeView();
}

// Return all the searchable widgets (views)
std::vector<QObject*> CrawlerWidget::doGetAllSearchables() const
{
    std::vector<QObject*> searchables =
    { logMainView, filteredView };

    return searchables;
}

// Update the state of the parent
void CrawlerWidget::doSendAllStateSignals()
{
    emit updateLineNumber( currentLineNumber_ );
    if ( !loadingInProgress_ )
        emit loadingFinished( LoadingStatus::Successful );
}

void CrawlerWidget::keyPressEvent( QKeyEvent* keyEvent )
{
    bool noModifier = keyEvent->modifiers() == Qt::NoModifier;

    if ( keyEvent->key() == Qt::Key_V && noModifier )
        visibilityBox->setCurrentIndex(
                ( visibilityBox->currentIndex() + 1 ) % visibilityBox->count() );
    else {
        const char character = (keyEvent->text())[0].toLatin1();

        if ( character == '+' )
            changeTopViewSize( 1 );
        else if ( character == '-' )
            changeTopViewSize( -1 );
        else
            QSplitter::keyPressEvent( keyEvent );
    }
}

//
// Public slots
//

void CrawlerWidget::stopLoading()
{
    logFilteredData_->interruptSearch();
    logData_->interruptLoading();
}

void CrawlerWidget::reload()
{
    searchState_.resetState();
    logFilteredData_->clearSearch();
    logFilteredData_->clearMarks();
    filteredView->updateData();
    printSearchInfoMessage();

    logData_->reload();

    // A reload is considered as a first load,
    // this is to prevent the "new data" icon to be triggered.
    firstLoadDone_ = false;
}

void CrawlerWidget::setEncoding( Encoding encoding )
{
    encodingSetting_ = encoding;
    updateEncoding();

    update();
}

//
// Protected functions
//
void CrawlerWidget::doSetData(
        std::shared_ptr<LogData> log_data,
        std::shared_ptr<LogFilteredData> filtered_data )
{
    logData_         = log_data.get();
    logFilteredData_ = filtered_data.get();
}

void CrawlerWidget::doSetQuickFindPattern(
        std::shared_ptr<QuickFindPattern> qfp )
{
    quickFindPattern_ = qfp;
}

void CrawlerWidget::doSetSavedSearches(
        std::shared_ptr<SavedSearches> saved_searches )
{
    savedSearches_ = saved_searches;

    // We do setup now, assuming doSetData has been called before
    // us, that's not great really...
    setup();
}

void CrawlerWidget::doSetViewContext(
        const char* view_context )
{
    LOG(logDEBUG) << "CrawlerWidget::doSetViewContext: " << view_context;

    CrawlerWidgetContext context = { view_context };

    setSizes( context.sizes() );
    ignoreCaseCheck->setCheckState( context.ignoreCase() ? Qt::Checked : Qt::Unchecked );

    auto auto_refresh_check_state = context.autoRefresh() ? Qt::Checked : Qt::Unchecked;
    searchRefreshCheck->setCheckState( auto_refresh_check_state );
    // Manually call the handler as it is not called when changing the state programmatically
    searchRefreshChangedHandler( auto_refresh_check_state );
}

std::shared_ptr<const ViewContextInterface>
CrawlerWidget::doGetViewContext() const
{
    auto context = std::make_shared<const CrawlerWidgetContext>(
            sizes(),
            ( ignoreCaseCheck->checkState() == Qt::Checked ),
            ( searchRefreshCheck->checkState() == Qt::Checked ) );

    return static_cast<std::shared_ptr<const ViewContextInterface>>( context );
}

//
// Slots
//

void CrawlerWidget::startNewSearch()
{
    // Record the search line in the recent list
    // (reload the list first in case another glogg changed it)
    GetPersistentInfo().retrieve( "savedSearches" );
    savedSearches_->addRecent( searchLineEdit->currentText() );
    GetPersistentInfo().save( "savedSearches" );

    // Update the SearchLine (history)
    updateSearchCombo();
    // Call the private function to do the search
    replaceCurrentSearch( searchLineEdit->currentText() );
}

void CrawlerWidget::stopSearch()
{
    logFilteredData_->interruptSearch();
    searchState_.stopSearch();
    printSearchInfoMessage();
}

// When receiving the 'newDataAvailable' signal from LogFilteredData
void CrawlerWidget::updateFilteredView( int nbMatches, int progress )
{
    LOG(logDEBUG) << "updateFilteredView received.";

    if ( progress == 100 ) {
        // Searching done
        printSearchInfoMessage( nbMatches );
        searchInfoLine->hideGauge();
        // De-activate the stop button
        stopButton->setEnabled( false );
    }
    else {
        // Search in progress
        // We ignore 0% and 100% to avoid a flash when the search is very short
        if ( progress > 0 ) {
            searchInfoLine->setText(
                    tr("Search in progress (%1 %)... %2 match%3 found so far.")
                    .arg( progress )
                    .arg( nbMatches )
                    .arg( nbMatches > 1 ? "es" : "" ) );
            searchInfoLine->displayGauge( progress );
        }
    }

    // If more (or less, e.g. come back to 0) matches have been found
    if ( nbMatches != nbMatches_ ) {
        nbMatches_ = nbMatches;

        // Recompute the content of the filtered window.
        filteredView->updateData();

        // Update the match overview
        overview_.updateData( logData_->getNbLine() );

        // New data found icon
        changeDataStatus( DataStatus::NEW_FILTERED_DATA );

        // Also update the top window for the coloured bullets.
        update();
    }
}

void CrawlerWidget::jumpToMatchingLine(int filteredLineNb)
{
    int mainViewLine = logFilteredData_->getMatchingLineNumber(filteredLineNb);
    logMainView->selectAndDisplayLine(mainViewLine);  // FIXME: should be done with a signal.
}

void CrawlerWidget::updateLineNumberHandler( int line )
{
    currentLineNumber_ = line;
    emit updateLineNumber( line );
}

void CrawlerWidget::markLineFromMain( qint64 line )
{
    if ( line < logData_->getNbLine() ) {
        if ( logFilteredData_->isLineMarked( line ) )
            logFilteredData_->deleteMark( line );
        else
            logFilteredData_->addMark( line );

        // Recompute the content of both window.
        filteredView->updateData();
        logMainView->updateData();

        // Update the match overview
        overview_.updateData( logData_->getNbLine() );

        // Also update the top window for the coloured bullets.
        update();
    }
}

void CrawlerWidget::markLineFromFiltered( qint64 line )
{
    if ( line < logFilteredData_->getNbLine() ) {
        qint64 line_in_file = logFilteredData_->getMatchingLineNumber( line );
        if ( logFilteredData_->filteredLineTypeByIndex( line )
                == LogFilteredData::Mark )
            logFilteredData_->deleteMark( line_in_file );
        else
            logFilteredData_->addMark( line_in_file );

        // Recompute the content of both window.
        filteredView->updateData();
        logMainView->updateData();

        // Update the match overview
        overview_.updateData( logData_->getNbLine() );

        // Also update the top window for the coloured bullets.
        update();
    }
}

void CrawlerWidget::applyConfiguration()
{
    std::shared_ptr<Configuration> config =
        Persistent<Configuration>( "settings" );
    QFont font = config->mainFont();

    LOG(logDEBUG) << "CrawlerWidget::applyConfiguration";

    // Whatever font we use, we should NOT use kerning
    font.setKerning( false );
    font.setFixedPitch( true );
#if QT_VERSION > 0x040700
    // Necessary on systems doing subpixel positionning (e.g. Ubuntu 12.04)
    font.setStyleStrategy( QFont::ForceIntegerMetrics );
#endif
    logMainView->setFont(font);
    filteredView->setFont(font);

    logMainView->setLineNumbersVisible( config->mainLineNumbersVisible() );
    filteredView->setLineNumbersVisible( config->filteredLineNumbersVisible() );

    overview_.setVisible( config->isOverviewVisible() );
    logMainView->refreshOverview();

    logMainView->updateDisplaySize();
    logMainView->update();
    filteredView->updateDisplaySize();
    filteredView->update();

    // Polling interval
    logData_->setPollingInterval(
            config->pollingEnabled() ? config->pollIntervalMs() : 0 );

    // Update the SearchLine (history)
    updateSearchCombo();
}

void CrawlerWidget::enteringQuickFind()
{
    LOG(logDEBUG) << "CrawlerWidget::enteringQuickFind";

    // Remember who had the focus (only if it is one of our views)
    QWidget* focus_widget =  QApplication::focusWidget();

    if ( ( focus_widget == logMainView ) || ( focus_widget == filteredView ) )
        qfSavedFocus_ = focus_widget;
    else
        qfSavedFocus_ = nullptr;
}

void CrawlerWidget::exitingQuickFind()
{
    // Restore the focus once the QFBar has been hidden
    if ( qfSavedFocus_ )
        qfSavedFocus_->setFocus();
}

void CrawlerWidget::loadingFinishedHandler( LoadingStatus status )
{
    loadingInProgress_ = false;

    // We need to refresh the main window because the view lines on the
    // overview have probably changed.
    overview_.updateData( logData_->getNbLine() );

    // FIXME, handle topLine
    // logMainView->updateData( logData_, topLine );
    logMainView->updateData();

        // Shall we Forbid starting a search when loading in progress?
        // searchButton->setEnabled( false );

    // searchButton->setEnabled( true );

    // See if we need to auto-refresh the search
    if ( searchState_.isAutorefreshAllowed() ) {
        if ( searchState_.isFileTruncated() )
            // We need to restart the search
            replaceCurrentSearch( searchLineEdit->currentText() );
        else
            logFilteredData_->updateSearch();
    }

    // Set the encoding for the views
    updateEncoding();

    emit loadingFinished( status );

    // Also change the data available icon
    if ( firstLoadDone_ )
        changeDataStatus( DataStatus::NEW_DATA );
    else
        firstLoadDone_ = true;
}

void CrawlerWidget::fileChangedHandler( LogData::MonitoredFileStatus status )
{
    // Handle the case where the file has been truncated
    if ( status == LogData::Truncated ) {
        // Clear all marks (TODO offer the option to keep them)
        logFilteredData_->clearMarks();
        if ( ! searchInfoLine->text().isEmpty() ) {
            // Invalidate the search
            logFilteredData_->clearSearch();
            filteredView->updateData();
            searchState_.truncateFile();
            printSearchInfoMessage();
            nbMatches_ = 0;
        }
    }
}

// Returns a pointer to the window in which the search should be done
AbstractLogView* CrawlerWidget::activeView() const
{
    QWidget* activeView;

    // Search in the window that has focus, or the window where 'Find' was
    // called from, or the main window.
    if ( filteredView->hasFocus() || logMainView->hasFocus() )
        activeView = QApplication::focusWidget();
    else
        activeView = qfSavedFocus_;

    if ( activeView ) {
        AbstractLogView* view = qobject_cast<AbstractLogView*>( activeView );
        return view;
    }
    else {
        LOG(logWARNING) << "No active view, defaulting to logMainView";
        return logMainView;
    }
}

void CrawlerWidget::searchForward()
{
    LOG(logDEBUG) << "CrawlerWidget::searchForward";

    activeView()->searchForward();
}

void CrawlerWidget::searchBackward()
{
    LOG(logDEBUG) << "CrawlerWidget::searchBackward";

    activeView()->searchBackward();
}

void CrawlerWidget::searchRefreshChangedHandler( int state )
{
    searchState_.setAutorefresh( state == Qt::Checked );
    printSearchInfoMessage( logFilteredData_->getNbMatches() );
}

void CrawlerWidget::searchTextChangeHandler()
{
    // We suspend auto-refresh
    searchState_.changeExpression();
    printSearchInfoMessage( logFilteredData_->getNbMatches() );
}

void CrawlerWidget::changeFilteredViewVisibility( int index )
{
    QStandardItem* item = visibilityModel_->item( index );
    FilteredView::Visibility visibility =
        static_cast< FilteredView::Visibility>( item->data().toInt() );

    filteredView->setVisibility( visibility );
}

void CrawlerWidget::addToSearch( const QString& string )
{
    QString text = searchLineEdit->currentText();

    if ( text.isEmpty() )
        text = string;
    else {
        // Escape the regexp chars from the string before adding it.
        text += ( '|' + QRegularExpression::escape( string ) );
    }

    searchLineEdit->setEditText( text );

    // Set the focus to lineEdit so that the user can press 'Return' immediately
    searchLineEdit->lineEdit()->setFocus();
}

void CrawlerWidget::mouseHoveredOverMatch( qint64 line )
{
    qint64 line_in_mainview = logFilteredData_->getMatchingLineNumber( line );

    overviewWidget_->highlightLine( line_in_mainview );
}

void CrawlerWidget::activityDetected()
{
    changeDataStatus( DataStatus::OLD_DATA );
}

//
// Private functions
//

// Build the widget and connect all the signals, this must be done once
// the data are attached.
void CrawlerWidget::setup()
{
    setOrientation(Qt::Vertical);

    assert( logData_ );
    assert( logFilteredData_ );

    // The views
    bottomWindow = new QWidget;
    overviewWidget_ = new OverviewWidget();
    logMainView     = new LogMainView(
            logData_, quickFindPattern_.get(), &overview_, overviewWidget_ );
    filteredView    = new FilteredView(
            logFilteredData_, quickFindPattern_.get() );

    overviewWidget_->setOverview( &overview_ );
    overviewWidget_->setParent( logMainView );

    // Connect the search to the top view
    logMainView->useNewFiltering( logFilteredData_ );

    // Construct the visibility button
    visibilityModel_ = new QStandardItemModel( this );

    QStandardItem *marksAndMatchesItem = new QStandardItem( tr( "Marks and matches" ) );
    QPixmap marksAndMatchesPixmap( 16, 10 );
    marksAndMatchesPixmap.fill( Qt::gray );
    marksAndMatchesItem->setIcon( QIcon( marksAndMatchesPixmap ) );
    marksAndMatchesItem->setData( FilteredView::MarksAndMatches );
    visibilityModel_->appendRow( marksAndMatchesItem );

    QStandardItem *marksItem = new QStandardItem( tr( "Marks" ) );
    QPixmap marksPixmap( 16, 10 );
    marksPixmap.fill( Qt::blue );
    marksItem->setIcon( QIcon( marksPixmap ) );
    marksItem->setData( FilteredView::MarksOnly );
    visibilityModel_->appendRow( marksItem );

    QStandardItem *matchesItem = new QStandardItem( tr( "Matches" ) );
    QPixmap matchesPixmap( 16, 10 );
    matchesPixmap.fill( Qt::red );
    matchesItem->setIcon( QIcon( matchesPixmap ) );
    matchesItem->setData( FilteredView::MatchesOnly );
    visibilityModel_->appendRow( matchesItem );

    QListView *visibilityView = new QListView( this );
    visibilityView->setMovement( QListView::Static );
    visibilityView->setMinimumWidth( 170 ); // Only needed with custom style-sheet

    visibilityBox = new QComboBox();
    visibilityBox->setModel( visibilityModel_ );
    visibilityBox->setView( visibilityView );

    // Select "Marks and matches" by default (same default as the filtered view)
    visibilityBox->setCurrentIndex( 0 );

    // TODO: Maybe there is some way to set the popup width to be
    // sized-to-content (as it is when the stylesheet is not overriden) in the
    // stylesheet as opposed to setting a hard min-width on the view above.
    visibilityBox->setStyleSheet( " \
        QComboBox:on {\
            padding: 1px 2px 1px 6px;\
            width: 19px;\
        } \
        QComboBox:!on {\
            padding: 1px 2px 1px 7px;\
            width: 19px;\
            height: 16px;\
            border: 1px solid gray;\
        } \
        QComboBox::drop-down::down-arrow {\
            width: 0px;\
            border-width: 0px;\
        } \
" );

    // Construct the Search Info line
    searchInfoLine = new InfoLine();
    searchInfoLine->setFrameStyle( QFrame::WinPanel | QFrame::Sunken );
    searchInfoLine->setLineWidth( 1 );
    searchInfoLineDefaultPalette = searchInfoLine->palette();

    ignoreCaseCheck = new QCheckBox( "Ignore &case" );
    searchRefreshCheck = new QCheckBox( "Auto-&refresh" );

    // Construct the Search line
    searchLabel = new QLabel(tr("&Text: "));
    searchLineEdit = new QComboBox;
    searchLineEdit->setEditable( true );
    searchLineEdit->setCompleter( 0 );
    searchLineEdit->addItems( savedSearches_->recentSearches() );
    searchLineEdit->setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Minimum );
    searchLineEdit->setSizeAdjustPolicy( QComboBox::AdjustToMinimumContentsLengthWithIcon );

    searchLabel->setBuddy( searchLineEdit );

    searchButton = new QToolButton();
    searchButton->setText( tr("&Search") );
    searchButton->setAutoRaise( true );

    stopButton = new QToolButton();
    stopButton->setIcon( QIcon(":/images/stop14.png") );
    stopButton->setAutoRaise( true );
    stopButton->setEnabled( false );

    QHBoxLayout* searchLineLayout = new QHBoxLayout;
    searchLineLayout->addWidget(searchLabel);
    searchLineLayout->addWidget(searchLineEdit);
    searchLineLayout->addWidget(searchButton);
    searchLineLayout->addWidget(stopButton);
    searchLineLayout->setContentsMargins(6, 0, 6, 0);
    stopButton->setSizePolicy( QSizePolicy( QSizePolicy::Maximum, QSizePolicy::Maximum ) );
    searchButton->setSizePolicy( QSizePolicy( QSizePolicy::Maximum, QSizePolicy::Maximum ) );

    QHBoxLayout* searchInfoLineLayout = new QHBoxLayout;
    searchInfoLineLayout->addWidget( visibilityBox );
    searchInfoLineLayout->addWidget( searchInfoLine );
    searchInfoLineLayout->addWidget( ignoreCaseCheck );
    searchInfoLineLayout->addWidget( searchRefreshCheck );

    // Construct the bottom window
    QVBoxLayout* bottomMainLayout = new QVBoxLayout;
    bottomMainLayout->addLayout(searchLineLayout);
    bottomMainLayout->addLayout(searchInfoLineLayout);
    bottomMainLayout->addWidget(filteredView);
    bottomMainLayout->setContentsMargins(2, 1, 2, 1);
    bottomWindow->setLayout(bottomMainLayout);

    addWidget( logMainView );
    addWidget( bottomWindow );

    // Default splitter position (usually overridden by the config file)
    QList<int> splitterSizes;
    splitterSizes += 400;
    splitterSizes += 100;
    setSizes( splitterSizes );

    // Default search checkboxes
    auto config = Persistent<Configuration>( "settings" );
    searchRefreshCheck->setCheckState( config->isSearchAutoRefreshDefault() ?
            Qt::Checked : Qt::Unchecked );
    // Manually call the handler as it is not called when changing the state programmatically
    searchRefreshChangedHandler( searchRefreshCheck->checkState() );
    ignoreCaseCheck->setCheckState( config->isSearchIgnoreCaseDefault() ?
            Qt::Checked : Qt::Unchecked );

    // Connect the signals
    connect(searchLineEdit->lineEdit(), SIGNAL( returnPressed() ),
            searchButton, SIGNAL( clicked() ));
    connect(searchLineEdit->lineEdit(), SIGNAL( textEdited( const QString& ) ),
            this, SLOT( searchTextChangeHandler() ));
    connect(searchButton, SIGNAL( clicked() ),
            this, SLOT( startNewSearch() ) );
    connect(stopButton, SIGNAL( clicked() ),
            this, SLOT( stopSearch() ) );

    connect(visibilityBox, SIGNAL( currentIndexChanged( int ) ),
            this, SLOT( changeFilteredViewVisibility( int ) ) );

    connect(logMainView, SIGNAL( newSelection( int ) ),
            logMainView, SLOT( update() ) );
    connect(filteredView, SIGNAL( newSelection( int ) ),
            this, SLOT( jumpToMatchingLine( int ) ) );
    connect(filteredView, SIGNAL( newSelection( int ) ),
            filteredView, SLOT( update() ) );
    connect(logMainView, SIGNAL( updateLineNumber( int ) ),
            this, SLOT( updateLineNumberHandler( int ) ) );
    connect(logMainView, SIGNAL( markLine( qint64 ) ),
            this, SLOT( markLineFromMain( qint64 ) ) );
    connect(filteredView, SIGNAL( markLine( qint64 ) ),
            this, SLOT( markLineFromFiltered( qint64 ) ) );

    connect(logMainView, SIGNAL( addToSearch( const QString& ) ),
            this, SLOT( addToSearch( const QString& ) ) );
    connect(filteredView, SIGNAL( addToSearch( const QString& ) ),
            this, SLOT( addToSearch( const QString& ) ) );

    connect(filteredView, SIGNAL( mouseHoveredOverLine( qint64 ) ),
            this, SLOT( mouseHoveredOverMatch( qint64 ) ) );
    connect(filteredView, SIGNAL( mouseLeftHoveringZone() ),
            overviewWidget_, SLOT( removeHighlight() ) );

    // Follow option (up and down)
    connect(this, SIGNAL( followSet( bool ) ),
            logMainView, SLOT( followSet( bool ) ) );
    connect(this, SIGNAL( followSet( bool ) ),
            filteredView, SLOT( followSet( bool ) ) );
    connect(logMainView, SIGNAL( followModeChanged( bool ) ),
            this, SIGNAL( followModeChanged( bool ) ) );
    connect(filteredView, SIGNAL( followModeChanged( bool ) ),
            this, SIGNAL( followModeChanged( bool ) ) );

    // Detect activity in the views
    connect(logMainView, SIGNAL( activity() ),
            this, SLOT( activityDetected() ) );
    connect(filteredView, SIGNAL( activity() ),
            this, SLOT( activityDetected() ) );

    connect( logFilteredData_, SIGNAL( searchProgressed( int, int ) ),
            this, SLOT( updateFilteredView( int, int ) ) );

    // Sent load file update to MainWindow (for status update)
    connect( logData_, SIGNAL( loadingProgressed( int ) ),
            this, SIGNAL( loadingProgressed( int ) ) );
    connect( logData_, SIGNAL( loadingFinished( LoadingStatus ) ),
            this, SLOT( loadingFinishedHandler( LoadingStatus ) ) );
    connect( logData_, SIGNAL( fileChanged( LogData::MonitoredFileStatus ) ),
            this, SLOT( fileChangedHandler( LogData::MonitoredFileStatus ) ) );

    // Search auto-refresh
    connect( searchRefreshCheck, SIGNAL( stateChanged( int ) ),
            this, SLOT( searchRefreshChangedHandler( int ) ) );

    // Advise the parent the checkboxes have been changed
    // (for maintaining default config)
    connect( searchRefreshCheck, SIGNAL( stateChanged( int ) ),
            this, SIGNAL( searchRefreshChanged( int ) ) );
    connect( ignoreCaseCheck, SIGNAL( stateChanged( int ) ),
            this, SIGNAL( ignoreCaseChanged( int ) ) );

    // Switch between views
    connect( logMainView, SIGNAL( exitView() ),
            filteredView, SLOT( setFocus() ) );
    connect( filteredView, SIGNAL( exitView() ),
            logMainView, SLOT( setFocus() ) );
}

// Create a new search using the text passed, replace the currently
// used one and destroy the old one.
void CrawlerWidget::replaceCurrentSearch( const QString& searchText )
{
    // Interrupt the search if it's ongoing
    logFilteredData_->interruptSearch();

    // We have to wait for the last search update (100%)
    // before clearing/restarting to avoid having remaining results.

    // FIXME: this is a bit of a hack, we call processEvents
    // for Qt to empty its event queue, including (hopefully)
    // the search update event sent by logFilteredData_. It saves
    // us the overhead of having proper sync.
    QApplication::processEvents( QEventLoop::ExcludeUserInputEvents );

    nbMatches_ = 0;

    // Clear and recompute the content of the filtered window.
    logFilteredData_->clearSearch();
    filteredView->updateData();

    // Update the match overview
    overview_.updateData( logData_->getNbLine() );

    if ( !searchText.isEmpty() ) {

        QString pattern;

        // Determine the type of regexp depending on the config
        static std::shared_ptr<Configuration> config =
            Persistent<Configuration>( "settings" );
        switch ( config->mainRegexpType() ) {
            case FixedString:
                pattern = QRegularExpression::escape(searchText);
                break;
            default:
                pattern = searchText;
                break;
        }

        // Set the pattern case insensitive if needed
        QRegularExpression::PatternOptions patternOptions =
                QRegularExpression::UseUnicodePropertiesOption
                | QRegularExpression::OptimizeOnFirstUsageOption;

        if ( ignoreCaseCheck->checkState() == Qt::Checked )
            patternOptions |= QRegularExpression::CaseInsensitiveOption;

        // Constructs the regexp
        QRegularExpression regexp( pattern, patternOptions );

        if ( regexp.isValid() ) {
            // Activate the stop button
            stopButton->setEnabled( true );
            // Start a new asynchronous search
            logFilteredData_->runSearch( regexp );
            // Accept auto-refresh of the search
            searchState_.startSearch();
        }
        else {
            // The regexp is wrong
            logFilteredData_->clearSearch();
            filteredView->updateData();
            searchState_.resetState();

            // Inform the user
            QString errorMessage = tr("Error in expression");
            const int offset = regexp.patternErrorOffset();
            if (offset != -1) {
                errorMessage += " at position ";
                errorMessage += QString::number(offset);
            }
            errorMessage += ": ";
            errorMessage += regexp.errorString();
            searchInfoLine->setPalette( errorPalette );
            searchInfoLine->setText( errorMessage );
        }
    }
    else {
        searchState_.resetState();
        printSearchInfoMessage();
    }
}

// Updates the content of the drop down list for the saved searches,
// called when the SavedSearch has been changed.
void CrawlerWidget::updateSearchCombo()
{
    const QString text = searchLineEdit->lineEdit()->text();
    searchLineEdit->clear();
    searchLineEdit->addItems( savedSearches_->recentSearches() );
    // In case we had something that wasn't added to the list (blank...):
    searchLineEdit->lineEdit()->setText( text );
}

// Print the search info message.
void CrawlerWidget::printSearchInfoMessage( int nbMatches )
{
    QString text;

    switch ( searchState_.getState() ) {
        case SearchState::NoSearch:
            // Blank text is fine
            break;
        case SearchState::Static:
            text = tr("%1 match%2 found.").arg( nbMatches )
                .arg( nbMatches > 1 ? "es" : "" );
            break;
        case SearchState::Autorefreshing:
            text = tr("%1 match%2 found. Search is auto-refreshing...").arg( nbMatches )
                .arg( nbMatches > 1 ? "es" : "" );
            break;
        case SearchState::FileTruncated:
        case SearchState::TruncatedAutorefreshing:
            text = tr("File truncated on disk, previous search results are not valid anymore.");
            break;
    }

    searchInfoLine->setPalette( searchInfoLineDefaultPalette );
    searchInfoLine->setText( text );
}

// Change the data status and, if needed, advise upstream.
void CrawlerWidget::changeDataStatus( DataStatus status )
{
    if ( ( status != dataStatus_ )
            && (! ( dataStatus_ == DataStatus::NEW_FILTERED_DATA
                    && status == DataStatus::NEW_DATA ) ) ) {
        dataStatus_ = status;
        emit dataStatusChanged( dataStatus_ );
    }
}

// Determine the right encoding and set the views.
void CrawlerWidget::updateEncoding()
{
    static const char* latin1_encoding = "iso-8859-1";
    static const char* utf8_encoding   = "utf-8";
    static const char* utf16le_encoding   = "utf-16le";
    static const char* utf16be_encoding   = "utf-16be";
    static const char* cp1251_encoding   = "CP1251";
    static const char* cp1252_encoding   = "CP1252";

    const char* encoding = latin1_encoding;

    switch ( encodingSetting_ ) {
        case ENCODING_AUTO:
            switch ( logData_->getDetectedEncoding() ) {
                case EncodingSpeculator::Encoding::ASCII7:
                    encoding = latin1_encoding;
                    encoding_text_ = tr( "US-ASCII" );
                    break;
                case EncodingSpeculator::Encoding::ASCII8:
                    encoding = latin1_encoding;
                    encoding_text_ = tr( "ISO-8859-1" );
                    break;
                case EncodingSpeculator::Encoding::UTF8:
                    encoding = utf8_encoding;
                    encoding_text_ = tr( "UTF-8" );
                    break;
                case EncodingSpeculator::Encoding::UTF16LE:
                    encoding = utf16le_encoding;
                    encoding_text_ = tr( "UTF-16LE" );
                    break;
                case EncodingSpeculator::Encoding::UTF16BE:
                    encoding = utf16be_encoding;
                    encoding_text_ = tr( "UTF-16BE" );
                    break;
            }
            break;
        case ENCODING_UTF8:
            encoding = utf8_encoding;
            encoding_text_ = tr( "Displayed as UTF-8" );
            break;
        case ENCODING_UTF16LE:
            encoding = utf16le_encoding;
            encoding_text_ = tr( "Displayed as UTF-16LE" );
            break;
        case ENCODING_UTF16BE:
            encoding = utf16be_encoding;
            encoding_text_ = tr( "Displayed as UTF-16BE" );
            break;
        case ENCODING_CP1251:
            encoding = cp1251_encoding;
            encoding_text_ = tr( "Displayed as CP1251" );
            break;
        case ENCODING_CP1252:
            encoding = cp1252_encoding;
            encoding_text_ = tr( "Displayed as CP1252" );
            break;
        case ENCODING_ISO_8859_1:
        default:
            encoding = latin1_encoding;
            encoding_text_ = tr( "Displayed as ISO-8859-1" );
            break;
    }

    // Determine the newline offsets for the encoding
    int before_cr;
    int after_cr;
    if ( encoding == utf16le_encoding ) {
        before_cr = 0;
        after_cr  = 1;
    }
    else if ( encoding == utf16be_encoding ) {
        before_cr = 1;
        after_cr  = 0;
    }
    else {
        before_cr = 0;
        after_cr  = 0;
    }

    logData_->setDisplayEncoding( encoding );
    logData_->setMultibyteEncodingOffsets( before_cr, after_cr );
    logMainView->forceRefresh();
    logFilteredData_->setDisplayEncoding( encoding );
    logFilteredData_->setMultibyteEncodingOffsets( before_cr, after_cr );
    filteredView->forceRefresh();
}

// Change the respective size of the two views
void CrawlerWidget::changeTopViewSize( int32_t delta )
{
    int min, max;
    getRange( 1, &min, &max );
    LOG(logDEBUG) << "CrawlerWidget::changeTopViewSize " << sizes()[0] << " " << min << " " << max;
    moveSplitter( closestLegalPosition( sizes()[0] + ( delta * 10 ), 1 ), 1 );
    LOG(logDEBUG) << "CrawlerWidget::changeTopViewSize " << sizes()[0];
}

//
// SearchState implementation
//
void CrawlerWidget::SearchState::resetState()
{
    state_ = NoSearch;
}

void CrawlerWidget::SearchState::setAutorefresh( bool refresh )
{
    autoRefreshRequested_ = refresh;

    if ( refresh ) {
        if ( state_ == Static )
            state_ = Autorefreshing;
        /*
        else if ( state_ == FileTruncated )
            state_ = TruncatedAutorefreshing;
        */
    }
    else {
        if ( state_ == Autorefreshing )
            state_ = Static;
        else if ( state_ == TruncatedAutorefreshing )
            state_ = FileTruncated;
    }
}

void CrawlerWidget::SearchState::truncateFile()
{
    if ( state_ == Autorefreshing || state_ == TruncatedAutorefreshing ) {
        state_ = TruncatedAutorefreshing;
    }
    else {
        state_ = FileTruncated;
    }
}

void CrawlerWidget::SearchState::changeExpression()
{
    if ( state_ == Autorefreshing )
        state_ = Static;
}

void CrawlerWidget::SearchState::stopSearch()
{
    if ( state_ == Autorefreshing )
        state_ = Static;
}

void CrawlerWidget::SearchState::startSearch()
{
    if ( autoRefreshRequested_ )
        state_ = Autorefreshing;
    else
        state_ = Static;
}

/*
 * CrawlerWidgetContext
 */
CrawlerWidgetContext::CrawlerWidgetContext( const char* string )
{
    QRegularExpression regex( "S(\\d+):(\\d+)" );
    QRegularExpressionMatch match = regex.match( string );
    if ( match.hasMatch() ) {
        sizes_ = { match.captured(1).toInt(), match.captured(2).toInt() };
        LOG(logDEBUG) << "sizes_: " << sizes_[0] << " " << sizes_[1];
    }
    else {
        LOG(logWARNING) << "Unrecognised view size: " << string;

        // Default values;
        sizes_ = { 100, 400 };
    }

    QRegularExpression case_refresh_regex( "IC(\\d+):AR(\\d+)" );
    match = case_refresh_regex.match( string );
    if ( match.hasMatch() ) {
        ignore_case_ = ( match.captured(1).toInt() == 1 );
        auto_refresh_ = ( match.captured(2).toInt() == 1 );

        LOG(logDEBUG) << "ignore_case_: " << ignore_case_ << " auto_refresh_: "
            << auto_refresh_;
    }
    else {
        LOG(logWARNING) << "Unrecognised case/refresh: " << string;
        ignore_case_ = false;
        auto_refresh_ = false;
    }
}

std::string CrawlerWidgetContext::toString() const
{
    char string[160];

    snprintf( string, sizeof string, "S%d:%d:IC%d:AR%d",
            sizes_[0], sizes_[1],
            ignore_case_, auto_refresh_ );

    return { string };
}