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, 2 insertions, 4 deletions

diff --git a/examples/animation/moveblocks/main.cpp b/examples/animation/moveblocks/main.cpp
index c43e841..97d3f81 100644
--- a/examples/animation/moveblocks/main.cpp
+++ b/examples/animation/moveblocks/main.cpp
@@ -108,8 +108,7 @@ class StateSwitcher : public QState
     Q_OBJECT
 public:
     StateSwitcher(QStateMachine *machine)
-        : QState(machine->rootState()), m_machine(machine),
-          m_stateCount(0), m_lastIndex(0)
+        : QState(machine), m_stateCount(0), m_lastIndex(0)
     { }
 //![10]
 
@@ -120,7 +119,7 @@ public:
         while ((n = (qrand() % m_stateCount + 1)) == m_lastIndex)
         { }
         m_lastIndex = n;
-        m_machine->postEvent(new StateSwitchEvent(n));
+        machine()->postEvent(new StateSwitchEvent(n));
     }
     virtual void onExit(QEvent *) {}
 //![11]
@@ -135,7 +134,6 @@ public:
 //![12]
 
 private:
-    QStateMachine *m_machine;
     int m_stateCount;
     int m_lastIndex;
 };