QStateMachine: cache expensive calculations.

As nothing changes in the state machine when selecting transitions for
events and then calculating the exit- and entry-sets, some calculations
can be cached.

The exit set for a transition was calculated multiple times. First in
removeConflictingTransitions, where the two loops would each calculate
them multiple times. Then secondly in microstep(), which would calculate
the exit set for all transitions.

Transition selection, exit set calculation, and entry set calculation
all calculate the transition domain and effective target states for
transitions.

Change-Id: I217328a73db2f71e371eb5f60a0c7b222303f0ca
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@theqtcompany.com>

1 files changed, 10 insertions, 7 deletions

diff --git a/src/corelib/statemachine/qstatemachine_p.h b/src/corelib/statemachine/qstatemachine_p.h
index a88f95f1f5..28fd96f507 100644
--- a/src/corelib/statemachine/qstatemachine_p.h
+++ b/src/corelib/statemachine/qstatemachine_p.h
@@ -75,6 +75,7 @@ class QState;
 class QAbstractAnimation;
 #endif
 
+struct CalculationCache;
 class QStateMachine;
 class Q_CORE_EXPORT QStateMachinePrivate : public QStatePrivate
 {
@@ -124,13 +125,14 @@ public:
     void clearHistory();
     QAbstractTransition *createInitialTransition() const;
 
-    void removeConflictingTransitions(QList<QAbstractTransition*> &enabledTransitions);
-    void microstep(QEvent *event, const QList<QAbstractTransition*> &transitionList);
-    QList<QAbstractTransition *> selectTransitions(QEvent *event);
+    void removeConflictingTransitions(QList<QAbstractTransition*> &enabledTransitions, CalculationCache *cache);
+    void microstep(QEvent *event, const QList<QAbstractTransition*> &transitionList, CalculationCache *cache);
+    QList<QAbstractTransition *> selectTransitions(QEvent *event, CalculationCache *cache);
     void exitStates(QEvent *event, const QList<QAbstractState *> &statesToExit_sorted,
                     const QHash<QAbstractState*, QList<QPropertyAssignment> > &assignmentsForEnteredStates);
-    QList<QAbstractState*> computeExitSet(const QList<QAbstractTransition*> &enabledTransitions);
-    QSet<QAbstractState*> computeExitSet_Unordered(const QList<QAbstractTransition*> &enabledTransitions);
+    QList<QAbstractState*> computeExitSet(const QList<QAbstractTransition*> &enabledTransitions, CalculationCache *cache);
+    QSet<QAbstractState*> computeExitSet_Unordered(const QList<QAbstractTransition*> &enabledTransitions, CalculationCache *cache);
+    QSet<QAbstractState*> computeExitSet_Unordered(QAbstractTransition *t, CalculationCache *cache);
     void executeTransitionContent(QEvent *event, const QList<QAbstractTransition*> &transitionList);
     void enterStates(QEvent *event, const QList<QAbstractState*> &exitedStates_sorted,
                      const QList<QAbstractState*> &statesToEnter_sorted,
@@ -141,9 +143,10 @@ public:
 #endif
                      );
     QList<QAbstractState*> computeEntrySet(const QList<QAbstractTransition*> &enabledTransitions,
-                                           QSet<QAbstractState*> &statesForDefaultEntry);
+                                           QSet<QAbstractState*> &statesForDefaultEntry, CalculationCache *cache);
     QAbstractState *getTransitionDomain(QAbstractTransition *t,
-                                        const QList<QAbstractState *> &effectiveTargetStates) const;
+                                        const QList<QAbstractState *> &effectiveTargetStates,
+                                        CalculationCache *cache) const;
     void addDescendantStatesToEnter(QAbstractState *state,
                                     QSet<QAbstractState*> &statesToEnter,
                                     QSet<QAbstractState*> &statesForDefaultEntry);