From bd15b23987e9d6d1f42fa8987e5c1ff5a1eeee8b Mon Sep 17 00:00:00 2001
From: Erik Verbruggen <erik.verbruggen@theqtcompany.com>
Date: Fri, 20 Mar 2015 14:20:16 +0100
Subject: 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>
---
 src/corelib/statemachine/qstatemachine_p.h | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

(limited to 'src/corelib/statemachine/qstatemachine_p.h')

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);
-- 
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