Utils: Add Undo facilities for aspects

Change-Id: I2a8acfa23b3a4303414be21af224b08c13561666
Reviewed-by: hjk <hjk@qt.io>

src/libs/utils/aspects.cpp

@@ -31,6 +31,7 @@
 #include <QSettings>
 #include <QSpinBox>
 #include <QTextEdit>
+#include <QUndoStack>
 
 using namespace Layouting;
 
@@ -84,6 +85,8 @@ public:
     BaseAspect::DataCreator m_dataCreator;
     BaseAspect::DataCloner m_dataCloner;
     QList<BaseAspect::DataExtractor> m_dataExtractors;
+
+    QUndoStack *m_undoStack = nullptr;
 };
 
 /*!
@@ -302,6 +305,29 @@ void BaseAspect::setToolTip(const QString &tooltip)
     }
 }
 
+void BaseAspect::setUndoStack(QUndoStack *undoStack)
+{
+    d->m_undoStack = undoStack;
+}
+
+QUndoStack *BaseAspect::undoStack() const
+{
+    return d->m_undoStack;
+}
+
+void BaseAspect::pushUndo(QUndoCommand *cmd)
+{
+    if (!cmd)
+        return;
+
+    if (d->m_undoStack)
+        d->m_undoStack->push(cmd);
+    else {
+        cmd->redo();
+        delete cmd;
+    }
+}
+
 bool BaseAspect::isEnabled() const
 {
     return d->m_enabled;
@@ -2645,6 +2671,14 @@ bool AspectContainer::isDirty()
     return false;
 }
 
+void AspectContainer::setUndoStack(QUndoStack *undoStack)
+{
+    BaseAspect::setUndoStack(undoStack);
+
+    for (BaseAspect *aspect : std::as_const(d->m_items))
+        aspect->setUndoStack(undoStack);
+}
+
 bool AspectContainer::equals(const AspectContainer &other) const
 {
     // FIXME: Expensive, but should not really be needed in a fully aspectified world.

src/libs/utils/aspects.h

@@ -15,9 +15,12 @@
 #include <memory>
 #include <optional>
 
+#include <QUndoCommand>
+
 QT_BEGIN_NAMESPACE
 class QAction;
 class QSettings;
+class QUndoStack;
 QT_END_NAMESPACE
 
 namespace Layouting { class LayoutItem; }
@@ -81,6 +84,10 @@ public:
     bool isAutoApply() const;
     virtual void setAutoApply(bool on);
 
+    virtual void setUndoStack(QUndoStack *undoStack);
+    QUndoStack *undoStack() const;
+    void pushUndo(QUndoCommand *cmd);
+
     bool isEnabled() const;
     void setEnabled(bool enabled);
     void setEnabler(BoolAspect *checker);
@@ -862,6 +869,7 @@ public:
     void copyFrom(const AspectContainer &other);
     void setAutoApply(bool on) override;
     bool isDirty() override;
+    void setUndoStack(QUndoStack *undoStack) override;
 
     template <typename T> T *aspect() const
     {
@@ -900,4 +908,61 @@ private:
     std::unique_ptr<Internal::AspectContainerPrivate> d;
 };
 
+// Because QObject cannot be a template
+class QTCREATOR_UTILS_EXPORT UndoSignaller : public QObject
+{
+    Q_OBJECT
+public:
+    void emitChanged() { emit changed(); }
+signals:
+    void changed();
+};
+
+template<class T>
+class QTCREATOR_UTILS_EXPORT UndoableValue
+{
+public:
+    class UndoCmd : public QUndoCommand
+    {
+    public:
+        UndoCmd(UndoableValue<T> *value, const T &oldValue, const T &newValue)
+            : m_value(value)
+            , m_oldValue(oldValue)
+            , m_newValue(newValue)
+        {}
+
+        void undo() override { m_value->setInternal(m_oldValue); }
+        void redo() override { m_value->setInternal(m_newValue); }
+
+    private:
+        UndoableValue<T> *m_value;
+        T m_oldValue;
+        T m_newValue;
+    };
+
+    QUndoCommand *set(const T &value)
+    {
+        if (m_value == value)
+            return nullptr;
+
+        return new UndoCmd(this, m_value, value);
+    }
+
+    void setSilently(const T &value) { m_value = value; }
+
+    T get() const { return m_value; }
+
+    UndoSignaller m_signal;
+
+private:
+    void setInternal(const T &value)
+    {
+        m_value = value;
+        m_signal.emitChanged();
+    }
+
+private:
+    T m_value;
+};
+
 } // namespace Utils