Make QStateMachine inherit QState

This removes the need for a "root state" in the machine; or rather,
the machine _is_ the root state.
User code can now pass in a QStateMachine directly to the QState
constructor, instead of machine->rootState().
This also means we could get rid of the "proxying" from the machine
to the root state for things like properties (initialState et al),
finished() signal and auto-reparenting of states (the ChildAdded
event hack).
A fun little side-effect of this change is that it's now possible
to embed state machines within state machines. We can't think of
a good use case yet where you would rather embed a stand-alone
state machine (with its own event processing etc.) rather than
having just a regular nested state, but it's neat and it works.

Reviewed-by: Eskil Abrahamsen Blomfeldt

1 files changed, 8 insertions, 9 deletions

diff --git a/src/corelib/statemachine/qstatemachine_p.h b/src/corelib/statemachine/qstatemachine_p.h
index 1335b93..21e405d 100644
--- a/src/corelib/statemachine/qstatemachine_p.h
+++ b/src/corelib/statemachine/qstatemachine_p.h
@@ -53,7 +53,8 @@
 // We mean it.
 //
 
-#include <private/qobject_p.h>
+#include "private/qstate_p.h"
+
 #include <QtCore/qcoreevent.h>
 #include <QtCore/qhash.h>
 #include <QtCore/qlist.h>
@@ -61,9 +62,6 @@
 #include <QtCore/qset.h>
 #include <QtCore/qvector.h>
 
-#include "qstate.h"
-#include "private/qstate_p.h"
-
 QT_BEGIN_NAMESPACE
 
 class QEvent;
@@ -81,7 +79,7 @@ class QAbstractAnimation;
 #endif
 
 class QStateMachine;
-class QStateMachinePrivate : public QObjectPrivate
+class QStateMachinePrivate : public QStatePrivate
 {
     Q_DECLARE_PUBLIC(QStateMachine)
 public:
@@ -101,7 +99,7 @@ public:
 
     static QStateMachinePrivate *get(QStateMachine *q);
 
-    static QState *findLCA(const QList<QAbstractState*> &states);
+    QState *findLCA(const QList<QAbstractState*> &states) const;
 
     static bool stateEntryLessThan(QAbstractState *s1, QAbstractState *s2);
     static bool stateExitLessThan(QAbstractState *s1, QAbstractState *s2);
@@ -116,6 +114,8 @@ public:
     void _q_animationFinished();
 #endif
 
+    QState *rootState() const;
+
     void microstep(QEvent *event, const QList<QAbstractTransition*> &transitionList);
     bool isPreempted(const QAbstractState *s, const QSet<QAbstractTransition*> &transitions) const;
     QSet<QAbstractTransition*> selectTransitions(QEvent *event) const;
@@ -133,8 +133,8 @@ public:
     bool isInFinalState(QAbstractState *s) const;
     static bool isFinal(const QAbstractState *s);
     static bool isParallel(const QAbstractState *s);
-    static bool isCompound(const QAbstractState *s);
-    static bool isAtomic(const QAbstractState *s);
+    bool isCompound(const QAbstractState *s) const;
+    bool isAtomic(const QAbstractState *s) const;
     static bool isDescendantOf(const QAbstractState *s, const QAbstractState *other);
     static QList<QState*> properAncestors(const QAbstractState *s, const QState *upperBound);
 
@@ -164,7 +164,6 @@ public:
     bool processingScheduled;
     bool stop;
     StopProcessingReason stopProcessingReason;
-    QState *rootState;
     QSet<QAbstractState*> configuration;
     QList<QEvent*> internalEventQueue;
     QList<QEvent*> externalEventQueue;