WIP: Restore previous DropArea when creating a new FloatingWindow

The idea works in theory, code is done, now just debugging is needed as there's some weird results still For issue #513
KDAB · Jul 20, 2024 · f7b38e0 · f7b38e0
1 parent bafe1f8
commit f7b38e0
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Showing 6 changed files with 44 additions and 13 deletions.
diff --git a/src/LayoutSaver.cpp b/src/LayoutSaver.cpp
@@ -553,7 +553,7 @@ bool LayoutSaver::restoreLayout(const QByteArray &data)
         flags.setFlag(FloatingWindowFlag::StartsMinimized, int(fw.windowState) & int(WindowState::Minimized));
 
         auto floatingWindow =
-            new Core::FloatingWindow({}, parent, flags);
+            new Core::FloatingWindow({}, nullptr, parent, flags);
         fw.floatingWindowInstance = floatingWindow;
         d->deserializeWindowGeometry(fw, floatingWindow->view()->window());
         if (!floatingWindow->deserialize(fw)) {

diff --git a/src/core/DockWidget.cpp b/src/core/DockWidget.cpp
@@ -622,7 +622,8 @@ Core::FloatingWindow *DockWidget::Private::morphIntoFloatingWindow()
         geo.setSize(geo.size().boundedTo(group->view()->maxSizeHint()));
         geo.setSize(geo.size().expandedTo(group->view()->minSize()));
         Core::FloatingWindow::ensureRectIsOnScreen(geo);
-        auto floatingWindow = new Core::FloatingWindow(group, geo);
+        auto floatingWindow = m_previousFloatingLayout ? FloatingWindow::fromExistingDropArea(group, geo, m_previousFloatingLayout->layout)
+                                                       : new Core::FloatingWindow(group, geo, nullptr);
 
         Core::AtomicSanityChecks checks(floatingWindow->dropArea()->rootItem());
         floatingWindow->view()->show();

diff --git a/src/core/DropArea.h b/src/core/DropArea.h
@@ -201,8 +201,7 @@ class PreviousFloatingLayout
     explicit PreviousFloatingLayout(Core::DropArea *);
     ~PreviousFloatingLayout();
 
-private:
-    Core::DropArea *const layout;
+    Core::DropArea *layout = nullptr;
 };
 
 }

diff --git a/src/core/FloatingWindow.cpp b/src/core/FloatingWindow.cpp
@@ -140,7 +140,7 @@ MainWindow *actualParent(MainWindow *candidate)
         : candidate;
 }
 
-FloatingWindow::FloatingWindow(Rect suggestedGeometry, MainWindow *parent,
+FloatingWindow::FloatingWindow(Rect suggestedGeometry, DropArea *dropAreaToReuse, MainWindow *parent,
                                FloatingWindowFlags requestedFlags)
     : Controller(ViewType::FloatingWindow,
                  Config::self().viewFactory()->createFloatingWindow(
@@ -151,7 +151,7 @@ FloatingWindow::FloatingWindow(Rect suggestedGeometry, MainWindow *parent,
                                                                 // Otherwise the
                                                                 // KDDockWidgets::TitleBar is the
                                                                 // draggable
-    , d(new Private(requestedFlags, this))
+    , d(new Private(requestedFlags, this, dropAreaToReuse))
     , m_titleBar(new Core::TitleBar(this))
 {
     view()->init();
@@ -205,8 +205,8 @@ FloatingWindow::FloatingWindow(Rect suggestedGeometry, MainWindow *parent,
 }
 
 FloatingWindow::FloatingWindow(Core::Group *group, Rect suggestedGeometry,
-                               MainWindow *parent)
-    : FloatingWindow({}, hackFindParentHarder(group, parent), floatingWindowFlagsForGroup(group))
+                               DropArea *dropAreaToReuse, MainWindow *parent)
+    : FloatingWindow({}, dropAreaToReuse, hackFindParentHarder(group, parent), floatingWindowFlagsForGroup(group))
 {
     ScopedValueRollback guard(m_disableSetVisible, true);
 
@@ -264,6 +264,27 @@ FloatingWindow::FloatingWindow(Core::Group *group, Rect suggestedGeometry,
         view()->setGeometry(suggestedGeometry);
 }
 
+/** static */
+FloatingWindow *FloatingWindow::fromExistingDropArea(Core::Group *group, Rect suggestedGeometry,
+                                                     DropArea *dropArea,
+                                                     MainWindow *parent)
+{
+    assert(dropArea);
+
+    // We're reusing a DropArea, transfer ownership to the new FloatingWindow.
+    // DockWidget's m_lastPositions has references to Core::Item* inside this DropArea, DockWidget
+    // no longer needs to keep the unused DropArea alive as it's now owned by FloatingWindow.
+    const auto allDockWidgets = DockRegistry::self()->dockwidgets();
+    for (Core::DockWidget *dw : allDockWidgets) {
+        if (dw->d->m_previousFloatingLayout && dw->d->m_previousFloatingLayout->layout == dropArea) {
+            dw->d->m_previousFloatingLayout->layout = nullptr;
+            dw->d->m_previousFloatingLayout = {};
+        }
+    }
+
+    return new FloatingWindow(group, suggestedGeometry, dropArea, parent);
+}
+
 FloatingWindow::~FloatingWindow()
 {
     m_inDtor = true;
@@ -394,6 +415,7 @@ void FloatingWindow::setSuggestedGeometry(Rect suggestedRect, SuggestedGeometryH
 void FloatingWindow::scheduleDeleteLater()
 {
     m_deleteScheduled = true;
+
     view()->d->setAboutToBeDestroyed();
     DockRegistry::self()->unregisterFloatingWindow(this);
     destroyLater();
@@ -851,10 +873,12 @@ inline FloatingWindowFlags flagsForFloatingWindow(FloatingWindowFlags requestedF
     return flags;
 }
 
-FloatingWindow::Private::Private(FloatingWindowFlags requestedFlags, FloatingWindow *q)
+FloatingWindow::Private::Private(FloatingWindowFlags requestedFlags, FloatingWindow *q, DropArea *dropAreaToReuse)
     : m_flags(flagsForFloatingWindow(requestedFlags))
-    , m_dropArea(new DropArea(q->view(), MainWindowOption_None))
+    , m_dropArea(dropAreaToReuse ? dropAreaToReuse : new DropArea(q->view(), MainWindowOption_None))
 {
+    if (dropAreaToReuse)
+        dropAreaToReuse->setParentView(q->view());
 }
 
 void FloatingWindow::saveLastFloatingLayout()
@@ -876,7 +900,7 @@ void FloatingWindow::saveLastFloatingLayout()
     // Give it to all dock widgets so they use it the next time they become floating
     auto layout = std::make_shared<PreviousFloatingLayout>(d->m_dropArea);
 
-    const auto docks = dockWidgets();
+    const auto docks = DockRegistry::self()->dockwidgetsReferencedByDropArea(d->m_dropArea);
     for (auto dock : docks) {
         if (dock->inDtor())
             continue;

diff --git a/src/core/FloatingWindow.h b/src/core/FloatingWindow.h
@@ -37,10 +37,17 @@ class DOCKS_EXPORT FloatingWindow : public Controller, public Draggable
     Q_OBJECT
 public:
     explicit FloatingWindow(
-        Rect suggestedGeometry, MainWindow *parent = nullptr,
+        Rect suggestedGeometry, DropArea *dropAreaToReuse, MainWindow *parent = nullptr,
         FloatingWindowFlags requestedFlags = FloatingWindowFlag::FromGlobalConfig);
+
     explicit FloatingWindow(Core::Group *group, Rect suggestedGeometry,
+                            DropArea *dropAreaToReuse = nullptr,
                             MainWindow *parent = nullptr);
+
+    static FloatingWindow *fromExistingDropArea(Core::Group *group, Rect suggestedGeometry,
+                                                DropArea *dropAreaToReuse,
+                                                MainWindow *parent = nullptr);
+
     virtual ~FloatingWindow() override;
 
     bool deserialize(const LayoutSaver::FloatingWindow &);

diff --git a/src/core/FloatingWindow_p.h b/src/core/FloatingWindow_p.h
@@ -25,7 +25,7 @@ namespace Core {
 class FloatingWindow::Private
 {
 public:
-    explicit Private(FloatingWindowFlags requestedFlags, FloatingWindow *q);
+    explicit Private(FloatingWindowFlags requestedFlags, FloatingWindow *q, DropArea *dropAreaToReuse);
 
     KDBindings::Signal<> activatedChanged;
     KDBindings::Signal<> numGroupsChanged;