From 0058ac5f28c64979f359972e03ee91ae146b0cd3 Mon Sep 17 00:00:00 2001
From: Simon Hausmann <simon.hausmann@qt.io>
Date: Tue, 14 Jun 2016 15:44:09 +0200
Subject: Clean up property cache array handling

The QQmlPropertyCacheVector in the CompilationUnit encapsulates the
property caches for the objects declared in the QML tree as well as the
bits indicating whether a VME meta-object is needed. The ref-counting
for the caches in that vector was done "manually" and thus error prone.
This patch replaces the vector with a wrapper container that has
explicit move semantics and takes care of the addref() and release()
calls upon insertion, replacement and destruction.

Change-Id: If805fe016f1a1c70e56f8a90909ab87b653ea026
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
---
 src/qml/qml/qqmlobjectcreator.cpp | 11 +++++-----
 src/qml/qml/qqmlobjectcreator_p.h |  2 +-
 src/qml/qml/qqmlpropertycache_p.h | 43 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 49 insertions(+), 7 deletions(-)

(limited to 'src/qml/qml')

diff --git a/src/qml/qml/qqmlobjectcreator.cpp b/src/qml/qml/qqmlobjectcreator.cpp
index 9e2040469b..6a54555f3f 100644
--- a/src/qml/qml/qqmlobjectcreator.cpp
+++ b/src/qml/qml/qqmlobjectcreator.cpp
@@ -73,7 +73,7 @@ QQmlObjectCreator::QQmlObjectCreator(QQmlContextData *parentContext, QV4::Compil
     : phase(Startup)
     , compilationUnit(compilationUnit)
     , resolvedTypes(compilationUnit->resolvedTypes)
-    , propertyCaches(compilationUnit->propertyCaches)
+    , propertyCaches(&compilationUnit->propertyCaches)
     , activeVMEDataForRootContext(activeVMEDataForRootContext)
 {
     init(parentContext);
@@ -97,7 +97,7 @@ QQmlObjectCreator::QQmlObjectCreator(QQmlContextData *parentContext, QV4::Compil
     : phase(Startup)
     , compilationUnit(compilationUnit)
     , resolvedTypes(compilationUnit->resolvedTypes)
-    , propertyCaches(compilationUnit->propertyCaches)
+    , propertyCaches(&compilationUnit->propertyCaches)
     , activeVMEDataForRootContext(0)
 {
     init(parentContext);
@@ -1147,7 +1147,7 @@ QObject *QQmlObjectCreator::createInstance(int index, QObject *parent, bool isCo
         return instance;
     }
 
-    QQmlRefPointer<QQmlPropertyCache> cache = propertyCaches.at(index).data();
+    QQmlRefPointer<QQmlPropertyCache> cache = propertyCaches->at(index);
     Q_ASSERT(!cache.isNull());
     if (installPropertyCache) {
         if (ddata->propertyCache)
@@ -1278,11 +1278,10 @@ bool QQmlObjectCreator::populateInstance(int index, QObject *instance, QObject *
     QV4::Scope valueScope(v4);
     QV4::ScopedValue scopeObjectProtector(valueScope);
 
-    QQmlRefPointer<QQmlPropertyCache> cache = propertyCaches.at(_compiledObjectIndex).data();
+    QQmlRefPointer<QQmlPropertyCache> cache = propertyCaches->at(_compiledObjectIndex);
 
     QQmlVMEMetaObject *vmeMetaObject = 0;
-    const bool needVMEMetaObject = propertyCaches.at(_compiledObjectIndex).flag();
-    if (needVMEMetaObject) {
+    if (propertyCaches->needsVMEMetaObject(_compiledObjectIndex)) {
         Q_ASSERT(!cache.isNull());
         // install on _object
         vmeMetaObject = new QQmlVMEMetaObject(_qobject, cache, compilationUnit, _compiledObjectIndex);
diff --git a/src/qml/qml/qqmlobjectcreator_p.h b/src/qml/qml/qqmlobjectcreator_p.h
index b4e706941b..2320edf809 100644
--- a/src/qml/qml/qqmlobjectcreator_p.h
+++ b/src/qml/qml/qqmlobjectcreator_p.h
@@ -140,7 +140,7 @@ private:
     QQmlGuardedContextData parentContext;
     QQmlContextData *context;
     const QHash<int, QV4::CompiledData::CompilationUnit::ResolvedTypeReference*> &resolvedTypes;
-    const QQmlPropertyCacheVector &propertyCaches;
+    const QQmlPropertyCacheVector *propertyCaches;
     QExplicitlySharedDataPointer<QQmlObjectCreatorSharedState> sharedState;
     bool topLevelCreator;
     void *activeVMEDataForRootContext;
diff --git a/src/qml/qml/qqmlpropertycache_p.h b/src/qml/qml/qqmlpropertycache_p.h
index 3e84fb3070..34b6b96ebe 100644
--- a/src/qml/qml/qqmlpropertycache_p.h
+++ b/src/qml/qml/qqmlpropertycache_p.h
@@ -655,6 +655,49 @@ const QMetaObject *QQmlMetaObject::metaObject() const
     else return _m.asT2();
 }
 
+class QQmlPropertyCacheVector
+{
+public:
+    QQmlPropertyCacheVector() {}
+    QQmlPropertyCacheVector(QQmlPropertyCacheVector &&other)
+        : data(std::move(other.data)) {}
+    QQmlPropertyCacheVector &operator=(QQmlPropertyCacheVector &&other) {
+        QVector<QFlagPointer<QQmlPropertyCache>> moved(std::move(other.data));
+        data.swap(moved);
+        return *this;
+    }
+
+    ~QQmlPropertyCacheVector() { clear(); }
+    void resize(int size) { return data.resize(size); }
+    int count() const { return data.count(); }
+    void clear()
+    {
+        for (int i = 0; i < data.count(); ++i) {
+            if (QQmlPropertyCache *cache = data.at(i).data())
+                cache->release();
+        }
+        data.clear();
+    }
+
+    void append(QQmlPropertyCache *cache) { cache->addref(); data.append(cache); }
+    QQmlPropertyCache *at(int index) const { return data.at(index).data(); }
+    void set(int index, QQmlPropertyCache *replacement) {
+        if (QQmlPropertyCache *oldCache = data.at(index).data()) {
+            if (replacement == oldCache)
+                return;
+            oldCache->release();
+        }
+        data[index] = replacement;
+        replacement->addref();
+    }
+
+    void setNeedsVMEMetaObject(int index) { data[index].setFlag(); }
+    bool needsVMEMetaObject(int index) const { return data.at(index).flag(); }
+private:
+    Q_DISABLE_COPY(QQmlPropertyCacheVector)
+    QVector<QFlagPointer<QQmlPropertyCache>> data;
+};
+
 QT_END_NAMESPACE
 
 #endif // QQMLPROPERTYCACHE_P_H
-- 
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