Convert the Log widget to use custom View/Model

Co-authored-by: sledgehammer999 <hammered999@gmail.com>

src/gui/log/loglistview.cpp

@@ -0,0 +1,140 @@
+/*
+ * Bittorrent Client using Qt and libtorrent.
+ * Copyright (C) 2020  Prince Gupta <jagannatharjun11@gmail.com>
+ * Copyright (C) 2019  sledgehammer999 <hammered999@gmail.com>
+ *
+ * This program 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 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * In addition, as a special exception, the copyright holders give permission to
+ * link this program with the OpenSSL project's "OpenSSL" library (or with
+ * modified versions of it that use the same license as the "OpenSSL" library),
+ * and distribute the linked executables. You must obey the GNU General Public
+ * License in all respects for all of the code used other than "OpenSSL".  If you
+ * modify file(s), you may extend this exception to your version of the file(s),
+ * but you are not obligated to do so. If you do not wish to do so, delete this
+ * exception statement from your version.
+ */
+
+#include "loglistview.h"
+
+#include <QApplication>
+#include <QClipboard>
+#include <QFontMetrics>
+#include <QKeyEvent>
+#include <QPainter>
+#include <QStyle>
+#include <QStyledItemDelegate>
+
+#include "logmodel.h"
+#include "uithememanager.h"
+
+namespace
+{
+    const QString SEPARATOR = QStringLiteral(" - ");
+
+    int horizontalAdvance(const QFontMetrics &fontMetrics, const QString &text)
+    {
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 11, 0))
+        return fontMetrics.horizontalAdvance(text);
+#else
+        return fontMetrics.width(text);
+#endif
+    }
+
+    QString logText(const QModelIndex &index)
+    {
+        return QString::fromLatin1("%1%2%3").arg(index.data(BaseLogModel::TimeRole).toString(), SEPARATOR
+                                                 , index.data(BaseLogModel::MessageRole).toString());
+    }
+
+    class LogItemDelegate : public QStyledItemDelegate
+    {
+    public:
+        using QStyledItemDelegate::QStyledItemDelegate;
+
+    private:
+        void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const override
+        {
+            painter->save();
+            QStyledItemDelegate::paint(painter, option, index); // paints background, focus rect and selection rect
+
+            const QStyle *style = option.widget ? option.widget->style() : QApplication::style();;
+            const QRect textRect = style->subElementRect(QStyle::SE_ItemViewItemText, &option, option.widget)
+                                   .adjusted(1, 0, 0, 0); // shift 1 to avoid text being too close to focus rect
+
+            QFont font = option.font;
+            if (option.font.pointSize() > 0)
+                font.setPointSize(option.font.pointSize()); // somehow this needs to be set directly otherwise painter will use default font
+            painter->setFont(font);
+
+            const QPen originalPen = painter->pen();
+            QPen coloredPen = originalPen;
+            coloredPen.setColor(Qt::darkGray);
+            painter->setPen(coloredPen);
+            const QString time = index.data(BaseLogModel::TimeRole).toString();
+            style->drawItemText(painter, textRect, option.displayAlignment, option.palette, (option.state & QStyle::State_Enabled), time);
+
+            painter->setPen(originalPen);
+            const QFontMetrics fontMetrics = painter->fontMetrics(); // option.fontMetrics adds extra padding to QFontMetrics::width
+            const int separatorCoordinateX = horizontalAdvance(fontMetrics, time);
+            style->drawItemText(painter, textRect.adjusted(separatorCoordinateX, 0, 0, 0), option.displayAlignment, option.palette
+                                , (option.state & QStyle::State_Enabled), SEPARATOR);
+
+            coloredPen.setColor(index.data(BaseLogModel::ForegroundRole).value<QColor>());
+            painter->setPen(coloredPen);
+            const int messageCoordinateX = separatorCoordinateX + horizontalAdvance(fontMetrics, SEPARATOR);
+            style->drawItemText(painter, textRect.adjusted(messageCoordinateX, 0, 0, 0), option.displayAlignment, option.palette
+                                , (option.state & QStyle::State_Enabled), index.data(BaseLogModel::MessageRole).toString());
+            painter->restore();
+        }
+
+        QSize sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const override
+        {
+            const QSize minimumFontPadding(4, 4);
+            const QSize fontSize = option.fontMetrics.size(0, logText(index)) + minimumFontPadding;
+            const QSize defaultSize = QStyledItemDelegate::sizeHint(option, index);
+            const QSize margins = (defaultSize - fontSize).expandedTo({0, 0});
+            return fontSize + margins;
+        }
+    };
+}
+
+LogListView::LogListView(QWidget *parent)
+    : QListView(parent)
+{
+    setSelectionMode(QAbstractItemView::ExtendedSelection);
+    setItemDelegate(new LogItemDelegate(this));
+
+#if defined(Q_OS_MAC)
+    setAttribute(Qt::WA_MacShowFocusRect, false);
+#endif
+}
+
+void LogListView::keyPressEvent(QKeyEvent *event)
+{
+    if (event->matches(QKeySequence::Copy))
+        copySelection();
+    else
+        QListView::keyPressEvent(event);
+}
+
+void LogListView::copySelection() const
+{
+    QStringList list;
+    const QModelIndexList selectedIndexes = selectionModel()->selectedRows();
+    for (const QModelIndex &index : selectedIndexes)
+        list.append(logText(index));
+    QApplication::clipboard()->setText(list.join('\n'));
+}