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authorMarc Mutz <marc.mutz@kdab.com>2015-01-08 14:57:09 +0100
committerMarc Mutz <marc.mutz@kdab.com>2015-01-09 12:06:23 +0100
commit3b9629e8bdbf23bb793c88f967b2cfe2b8256278 (patch)
tree2eff4cedcccf1683845579c6cc587dc68f1d6973 /src/corelib/statemachine
parent65eb57392685d69313217fd17e06376db8f9c05b (diff)
QStateMachine: replace a QHash key involving a QPointer
Using QPointers (or any type that makes a QPointer part of its identity) as a key in any associative container is wrong. They get externally set to nullptr, violating the associative container's class invariants, which could lead to data corruption, even though bucket-based hash implementations are less susceptible than binary trees. To fix, write a new class that acts much like the old QPair<QPointer<>,QByteArray>, but uses the QPointer only as a guard, not as part of its identity. To preseve identity, also saves the naked pointer originally passed and uses that for op== and qHash(). Change-Id: I4fa5a6bf86bad8fe7f5abe53d7c7f3ad3754d8d6 Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Diffstat (limited to 'src/corelib/statemachine')
-rw-r--r--src/corelib/statemachine/qstatemachine.cpp7
-rw-r--r--src/corelib/statemachine/qstatemachine_p.h19
2 files changed, 22 insertions, 4 deletions
diff --git a/src/corelib/statemachine/qstatemachine.cpp b/src/corelib/statemachine/qstatemachine.cpp
index 27c7b077c6..fa5e49c882 100644
--- a/src/corelib/statemachine/qstatemachine.cpp
+++ b/src/corelib/statemachine/qstatemachine.cpp
@@ -947,14 +947,15 @@ QList<QPropertyAssignment> QStateMachinePrivate::restorablesToPropertyList(const
QList<QPropertyAssignment> result;
QHash<RestorableId, QVariant>::const_iterator it;
for (it = restorables.constBegin(); it != restorables.constEnd(); ++it) {
- if (!it.key().first) {
+ const RestorableId &id = it.key();
+ if (!id.object()) {
// Property object was deleted
continue;
}
#ifdef QSTATEMACHINE_RESTORE_PROPERTIES_DEBUG
- qDebug() << q_func() << ": restoring" << it.key().first << it.key().second << "to" << it.value();
+ qDebug() << q_func() << ": restoring" << id.object() << id.proertyName() << "to" << it.value();
#endif
- result.append(QPropertyAssignment(it.key().first, it.key().second, it.value(), /*explicitlySet=*/false));
+ result.append(QPropertyAssignment(id.object(), id.propertyName(), it.value(), /*explicitlySet=*/false));
}
return result;
}
diff --git a/src/corelib/statemachine/qstatemachine_p.h b/src/corelib/statemachine/qstatemachine_p.h
index 465d8aff0d..51eed07548 100644
--- a/src/corelib/statemachine/qstatemachine_p.h
+++ b/src/corelib/statemachine/qstatemachine_p.h
@@ -189,7 +189,24 @@ public:
void cancelAllDelayedEvents();
#ifndef QT_NO_PROPERTIES
- typedef QPair<QPointer<QObject>, QByteArray> RestorableId;
+ class RestorableId {
+ QPointer<QObject> guard;
+ QObject *obj;
+ QByteArray prop;
+ // two overloads because friends can't have default arguments
+ friend uint qHash(const RestorableId &key, uint seed) Q_DECL_NOEXCEPT_EXPR(noexcept(std::declval<QByteArray>()))
+ { return qHash(qMakePair(key.obj, key.prop), seed); }
+ friend uint qHash(const RestorableId &key) Q_DECL_NOEXCEPT_EXPR(noexcept(qHash(key, 0U)))
+ { return qHash(key, 0U); }
+ friend bool operator==(const RestorableId &lhs, const RestorableId &rhs) Q_DECL_NOTHROW
+ { return lhs.obj == rhs.obj && lhs.prop == rhs.prop; }
+ friend bool operator!=(const RestorableId &lhs, const RestorableId &rhs) Q_DECL_NOTHROW
+ { return !operator==(lhs, rhs); }
+ public:
+ explicit RestorableId(QObject *o, QByteArray p) Q_DECL_NOTHROW : guard(o), obj(o), prop(qMove(p)) {}
+ QObject *object() const Q_DECL_NOTHROW { return guard; }
+ QByteArray propertyName() const Q_DECL_NOTHROW { return prop; }
+ };
QHash<QAbstractState*, QHash<RestorableId, QVariant> > registeredRestorablesForState;
bool hasRestorable(QAbstractState *state, QObject *object, const QByteArray &propertyName) const;
QVariant savedValueForRestorable(const QList<QAbstractState*> &exitedStates_sorted,