Port sidebar to QDockWidget

With this MR, the sidebar can now be (if not locked):
* docked to the left or right side
* undocked and floated as an independent window
* closed with the close button in the header

BUG: 455013

interfaces/viewerinterface.h

@@ -79,6 +79,13 @@ public:
      */
     virtual bool openNewFilesInTabs() const = 0;
 
+    /**
+     * Returns the sidebar container.
+     *
+     * @since 23.04
+     */
+    virtual QWidget *getSideContainer() const = 0;
+
     // SIGNALS
     /**
      * The signal 'openSourceReference' is emitted whenever the user has triggered a source

part/part.cpp

@@ -1107,6 +1107,11 @@ bool Part::openNewFilesInTabs() const
     return Okular::Settings::self()->shellOpenFileInTabs();
 }
 
+QWidget *Part::getSideContainer() const
+{
+    return m_sidebar->getSideContainer();
+}
+
 bool Part::activateTabIfAlreadyOpenFile() const
 {
     return Okular::Settings::self()->switchToTabIfOpen();

part/part.h

@@ -147,6 +147,7 @@ public:
     bool areSourceLocationsShownGraphically() const override;
     void setShowSourceLocationsGraphically(bool show) override;
     bool openNewFilesInTabs() const override;
+    QWidget *getSideContainer() const override;
     Q_INVOKABLE bool activateTabIfAlreadyOpenFile() const;
 
     void setModified(bool modified) override;

part/sidebar.cpp

@@ -166,6 +166,11 @@ void Sidebar::moveSplitter(int sideWidgetSize)
     d->splitter->setSizes(splitterSizeList);
 }
 
+QWidget *Sidebar::getSideContainer() const
+{
+    return d->sideContainer;
+}
+
 void Sidebar::splitterMoved(int /*pos*/, int index)
 {
     // if the side panel has been resized, save splitter sizes

part/sidebar.h

@@ -33,6 +33,8 @@ public:
 
     void moveSplitter(int sideWidgetSize);
 
+    QWidget *getSideContainer() const;
+
 Q_SIGNALS:
     void urlsDropped(const QList<QUrl> &urls);
 

shell/shell.cpp

@@ -36,6 +36,7 @@
 #include <KXMLGUIFactory>
 #include <QApplication>
 #include <QDBusConnection>
+#include <QDockWidget>
 #include <QDragMoveEvent>
 #include <QFileDialog>
 #include <QMenuBar>
@@ -62,6 +63,86 @@ static const char *shouldShowToolBarComingFromFullScreen = "shouldShowToolBarCom
 static const char *const SESSION_URL_KEY = "Urls";
 static const char *const SESSION_TAB_KEY = "ActiveTab";
 
+static constexpr char SIDEBAR_LOCKED_KEY[] = "LockSidebar";
+static constexpr char SIDEBAR_VISIBLE_KEY[] = "ShowSidebar";
+
+/**
+ * Groups sidebar containers in a QDockWidget.
+ *
+ * This control groups all the sidebar containers provided by each tab (the Part object),
+ * allowing the user to dock it to the left and right sides of the window,
+ * or detach it from the window altogether.
+ */
+class Sidebar : public QDockWidget
+{
+    Q_OBJECT
+
+public:
+    explicit Sidebar(QWidget *parent = nullptr)
+        : QDockWidget(parent)
+    {
+        setAllowedAreas(Qt::LeftDockWidgetArea | Qt::RightDockWidgetArea);
+        setFeatures(defaultFeatures());
+
+        m_stackedWidget = new QStackedWidget;
+        setWidget(m_stackedWidget);
+    }
+
+    bool isLocked() const
+    {
+        return features().testFlag(NoDockWidgetFeatures);
+    }
+
+    void setLocked(bool locked)
+    {
+        setFeatures(locked ? NoDockWidgetFeatures : defaultFeatures());
+
+        // show titlebar only if not locked
+        if (locked) {
+            if (!m_dumbTitleWidget) {
+                m_dumbTitleWidget = new QWidget;
+            }
+            setTitleBarWidget(m_dumbTitleWidget);
+        } else {
+            setTitleBarWidget(nullptr);
+        }
+    }
+
+    int indexOf(QWidget *widget) const
+    {
+        return m_stackedWidget->indexOf(widget);
+    }
+
+    void addWidget(QWidget *widget)
+    {
+        m_stackedWidget->addWidget(widget);
+    }
+
+    void removeWidget(QWidget *widget)
+    {
+        m_stackedWidget->removeWidget(widget);
+    }
+
+    void setCurrentWidget(QWidget *widget)
+    {
+        m_stackedWidget->setCurrentWidget(widget);
+    }
+
+private:
+    static DockWidgetFeatures defaultFeatures()
+    {
+        DockWidgetFeatures dockFeatures = DockWidgetClosable | DockWidgetMovable;
+        if (!KWindowSystem::isPlatformWayland()) { // TODO : Remove this check when QTBUG-87332 is fixed
+            dockFeatures |= DockWidgetFloatable;
+        }
+
+        return dockFeatures;
+    }
+
+    QStackedWidget *m_stackedWidget = nullptr;
+    QWidget *m_dumbTitleWidget = nullptr;
+};
+
 Shell::Shell(const QString &serializedOptions)
     : KParts::MainWindow()
     , m_menuBarWasShown(true)
@@ -126,12 +207,27 @@ Shell::Shell(const QString &serializedOptions)
         connect(m_tabWidget, &QTabWidget::tabCloseRequested, this, &Shell::closeTab);
         connect(m_tabWidget->tabBar(), &QTabBar::tabMoved, this, &Shell::moveTabData);
 
+        m_sidebar = new Sidebar;
+        m_sidebar->setObjectName(QStringLiteral("okular_sidebar"));
+        m_sidebar->setContextMenuPolicy(Qt::ActionsContextMenu);
+        m_sidebar->setWindowTitle(i18n("Sidebar"));
+        connect(m_sidebar, &QDockWidget::visibilityChanged, this, [this](bool visible) {
+            // sync sidebar visibility with the m_showSidebarAction only if welcome screen is hidden
+            if (m_showSidebarAction && m_centralStackedWidget->currentWidget() != m_welcomeScreen) {
+                m_showSidebarAction->setChecked(visible);
+            }
+        });
+        addDockWidget(Qt::LeftDockWidgetArea, m_sidebar);
+
         // then, setup our actions
         setupActions();
         connect(QCoreApplication::instance(), &QCoreApplication::aboutToQuit, this, &QObject::deleteLater);
         // and integrate the part's GUI with the shell's
         setupGUI(Keys | ToolBar | Save);
 
+        // NOTE : apply default sidebar width only after calling setupGUI(...)
+        resizeDocks({m_sidebar}, {200}, Qt::Horizontal);
+
         m_tabs.append(TabState(firstPart));
         m_tabWidget->addTab(firstPart->widget(), QString()); // triggers setActiveTab that calls createGUI( part )
 
@@ -367,11 +463,25 @@ void Shell::readSettings()
         m_menuBarWasShown = group.readEntry(shouldShowMenuBarComingFromFullScreen, true);
         m_toolBarWasShown = group.readEntry(shouldShowToolBarComingFromFullScreen, true);
     }
+
+    const KConfigGroup sidebarGroup = KSharedConfig::openConfig()->group("General");
+    m_sidebar->setVisible(sidebarGroup.readEntry(SIDEBAR_VISIBLE_KEY, true));
+    m_sidebar->setLocked(sidebarGroup.readEntry(SIDEBAR_LOCKED_KEY, true));
+
+    m_showSidebarAction->setChecked(m_sidebar->isVisibleTo(this));
+    m_lockSidebarAction->setChecked(m_sidebar->isLocked());
 }
 
 void Shell::writeSettings()
 {
     saveRecents();
+
+    KConfigGroup sidebarGroup = KSharedConfig::openConfig()->group("General");
+    sidebarGroup.writeEntry(SIDEBAR_LOCKED_KEY, m_sidebar->isLocked());
+    // NOTE : Consider whether the m_showSidebarAction is checked, because
+    // the sidebar can be forcibly hidden if the welcome screen is displayed
+    sidebarGroup.writeEntry(SIDEBAR_VISIBLE_KEY, m_sidebar->isVisibleTo(this) || m_showSidebarAction->isChecked());
+
     KConfigGroup group = KSharedConfig::openConfig()->group("Desktop Entry");
     group.writeEntry("FullScreen", m_fullScreenAction->isChecked());
     if (m_fullScreenAction->isChecked()) {
@@ -425,6 +535,19 @@ void Shell::setupActions()
     m_undoCloseTab->setIcon(QIcon::fromTheme(QStringLiteral("edit-undo")));
     m_undoCloseTab->setEnabled(false);
     connect(m_undoCloseTab, &QAction::triggered, this, &Shell::undoCloseTab);
+
+    m_showSidebarAction = actionCollection()->addAction(QStringLiteral("okular_show_sidebar"));
+    m_showSidebarAction->setCheckable(true);
+    m_showSidebarAction->setIcon(QIcon::fromTheme(QStringLiteral("sidebar-show-symbolic")));
+    m_showSidebarAction->setText(i18n("Show Sidebar"));
+    connect(m_showSidebarAction, &QAction::triggered, m_sidebar, &Sidebar::setVisible);
+
+    m_lockSidebarAction = actionCollection()->addAction(QStringLiteral("okular_lock_sidebar"));
+    m_lockSidebarAction->setCheckable(true);
+    m_lockSidebarAction->setIcon(QIcon::fromTheme(QStringLiteral("lock")));
+    m_lockSidebarAction->setText(i18n("Lock Sidebar"));
+    connect(m_lockSidebarAction, &QAction::triggered, m_sidebar, &Sidebar::setLocked);
+    m_sidebar->addAction(m_lockSidebarAction);
 }
 
 void Shell::saveProperties(KConfigGroup &group)
@@ -673,7 +796,24 @@ bool Shell::queryClose()
 void Shell::setActiveTab(int tab)
 {
     m_tabWidget->setCurrentIndex(tab);
+
+    // NOTE : createGUI(...) breaks the visibility of the sidebar, so we need
+    // to save and restore it
+    const bool isSidebarVisible = m_sidebar->isVisible();
     createGUI(m_tabs[tab].part);
+    m_sidebar->setVisible(isSidebarVisible);
+
+    // dock KPart's sidebar if new and make it current
+    Okular::ViewerInterface *iPart = qobject_cast<Okular::ViewerInterface *>(m_tabs[tab].part);
+    Q_ASSERT(iPart);
+    QWidget *sideContainer = iPart->getSideContainer();
+    if (m_sidebar->indexOf(sideContainer) == -1) {
+        m_sidebar->addWidget(sideContainer);
+        if (m_sidebar->maximumWidth() > sideContainer->maximumWidth()) {
+            m_sidebar->setMaximumWidth(sideContainer->maximumWidth());
+        }
+    }
+    m_sidebar->setCurrentWidget(sideContainer);
 
     m_printAction->setEnabled(m_tabs[tab].printEnabled);
     m_closeAction->setEnabled(m_tabs[tab].closeEnabled);
@@ -689,6 +829,13 @@ void Shell::closeTab(int tab)
             part->factory()->removeClient(part);
         }
         part->disconnect();
+
+        Okular::ViewerInterface *iPart = qobject_cast<Okular::ViewerInterface *>(m_tabs[tab].part);
+        Q_ASSERT(iPart);
+        QWidget *sideContainer = iPart->getSideContainer();
+        m_sidebar->removeWidget(sideContainer);
+        connect(part, &QObject::destroyed, sideContainer, &QObject::deleteLater);
+
         part->deleteLater();
         m_tabs.removeAt(tab);
         m_tabWidget->removeTab(tab);
@@ -776,7 +923,7 @@ void Shell::applyOptionsToPart(QObject *part, const QString &serializedOptions)
     }
 }
 
-void Shell::connectPart(QObject *part)
+void Shell::connectPart(const KParts::ReadWritePart *part)
 {
     // We're abusing the fact we know the part is our part here
     connect(this, SIGNAL(moveSplitter(int)), part, SLOT(moveSplitter(int)));                     // clazy:exclude=old-style-connect
@@ -788,6 +935,12 @@ void Shell::connectPart(QObject *part)
     // Otherwise the QSize,QSize gets turned into QSize, QSize that is not normalized signals and is slightly slower
     connect(part, SIGNAL(fitWindowToPage(QSize,QSize)), this, SLOT(slotFitWindowToPage(QSize,QSize)));   // clazy:exclude=old-style-connect
     // clang-format on
+
+    // since sidebar is now docked to main window, we use another action
+    // to show/hide it, so we should hide a similar KPart's action
+    if (QAction *action = part->actionCollection()->action(QStringLiteral("show_leftpanel"))) {
+        action->setVisible(false);
+    }
 }
 
 void Shell::print()
@@ -903,12 +1056,17 @@ void Shell::slotFitWindowToPage(const QSize pageViewSize, const QSize pageSize)
 
 void Shell::hideWelcomeScreen()
 {
+    m_sidebar->setVisible(m_showSidebarAction->isChecked());
     m_centralStackedWidget->setCurrentWidget(m_tabWidget);
+    m_showSidebarAction->setEnabled(true);
 }
 
 void Shell::showWelcomeScreen()
 {
+    m_showSidebarAction->setEnabled(false);
     m_centralStackedWidget->setCurrentWidget(m_welcomeScreen);
+    m_sidebar->setVisible(false);
+
     refreshRecentsOnWelcomeScreen();
 }
 
@@ -927,4 +1085,6 @@ void Shell::forgetRecentItem(QUrl const &url)
     }
 }
 
+#include "shell.moc"
+
 /* kate: replace-tabs on; indent-width 4; */

shell/shell.h

@@ -24,6 +24,7 @@
 
 #include "welcomescreen.h"
 
+class Sidebar;
 class KRecentFilesAction;
 class KToggleAction;
 class QTabWidget;
@@ -155,7 +156,7 @@ private:
     void setupActions();
     void openNewTab(const QUrl &url, const QString &serializedOptions);
     void applyOptionsToPart(QObject *part, const QString &serializedOptions);
-    void connectPart(QObject *part);
+    void connectPart(const KParts::ReadWritePart *part);
     int findTabIndex(QObject *sender) const;
     int findTabIndex(const QUrl &url) const;
 
@@ -177,6 +178,7 @@ private:
     KToggleAction *m_openInTab;
     WelcomeScreen *m_welcomeScreen;
     QStackedWidget *m_centralStackedWidget;
+    Sidebar *m_sidebar = nullptr;
 
     struct TabState {
         explicit TabState(KParts::ReadWritePart *p)
@@ -194,6 +196,8 @@ private:
     QAction *m_nextTabAction;
     QAction *m_prevTabAction;
     QAction *m_undoCloseTab;
+    QAction *m_showSidebarAction = nullptr;
+    QAction *m_lockSidebarAction = nullptr;
 
 #ifndef Q_OS_WIN
     KActivities::ResourceInstance *m_activityResource;

shell/shell.rc

@@ -1,6 +1,6 @@
 <?xml version="1.0"?>
 <!DOCTYPE gui SYSTEM "kpartgui.dtd">
-<gui version="9" name="okular_shell" >
+<gui version="10" name="okular_shell" >
  <MenuBar>
   <Menu name="file" >
    <DefineGroup append="open_merge" name="file_open" />
@@ -13,6 +13,7 @@
   </Menu-->
   <Menu name="settings" >
    <DefineGroup append="show_merge" name="show_merge" />
+   <Action name="okular_show_sidebar" append="show_merge" />
    <DefineGroup append="configure_merge" name="configure_merge" />
   </Menu>
   <Merge/>
@@ -21,8 +22,12 @@
   </Menu>
  </MenuBar>
  <ToolBar noMerge="1" name="mainToolBar" >
+  <Action name="okular_show_sidebar" />
   <text>Main Toolbar</text>
   <!--Action name="file_open_recent" /-->
   <!--Action name="file_print" /-->
  </ToolBar>
+ <ActionProperties scheme="Default">
+  <Action priority="0" name="okular_show_sidebar"/>
+ </ActionProperties>
 </gui>