1 files changed, 53 insertions, 32 deletions

diff --git a/src/qml/qml/qqmlengine_p.h b/src/qml/qml/qqmlengine_p.h
index 072a6c436a..003cfa0112 100644
--- a/src/qml/qml/qqmlengine_p.h
+++ b/src/qml/qml/qqmlengine_p.h
@@ -1,31 +1,37 @@
 /****************************************************************************
 **
-** Copyright (C) 2015 The Qt Company Ltd.
-** Contact: http://www.qt.io/licensing/
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtQml module of the Qt Toolkit.
 **
-** $QT_BEGIN_LICENSE:LGPL21$
+** $QT_BEGIN_LICENSE:LGPL$
 ** Commercial License Usage
 ** Licensees holding valid commercial Qt licenses may use this file in
 ** accordance with the commercial license agreement provided with the
 ** Software or, alternatively, in accordance with the terms contained in
 ** a written agreement between you and The Qt Company. For licensing terms
-** and conditions see http://www.qt.io/terms-conditions. For further
-** information use the contact form at http://www.qt.io/contact-us.
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
 **
 ** GNU Lesser General Public License Usage
 ** Alternatively, this file may be used under the terms of the GNU Lesser
-** General Public License version 2.1 or version 3 as published by the Free
-** Software Foundation and appearing in the file LICENSE.LGPLv21 and
-** LICENSE.LGPLv3 included in the packaging of this file. Please review the
-** following information to ensure the GNU Lesser General Public License
-** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
-** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
 **
-** As a special exception, The Qt Company gives you certain additional
-** rights. These rights are described in The Qt Company LGPL Exception
-** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
 **
 ** $QT_END_LICENSE$
 **
@@ -216,9 +222,6 @@ public:
     bool isTypeLoaded(const QUrl &url) const;
     bool isScriptLoaded(const QUrl &url) const;
 
-    inline void setDebugChangesCache(const QHash<QUrl, QByteArray> &changes);
-    inline QHash<QUrl, QByteArray> debugChangesCache();
-
     void sendQuit();
     void warning(const QQmlError &);
     void warning(const QList<QQmlError> &);
@@ -258,15 +261,46 @@ private:
     QHash<QPair<QQmlType *, int>, QQmlPropertyCache *> typePropertyCache;
     QHash<int, int> m_qmlLists;
     QHash<int, QQmlCompiledData *> m_compositeTypes;
-    QHash<QUrl, QByteArray> debugChangesHash;
     static bool s_designerMode;
 
     // These members is protected by the full QQmlEnginePrivate::mutex mutex
     struct Deletable { Deletable():next(0) {} virtual ~Deletable() {} Deletable *next; };
     QFieldList<Deletable, &Deletable::next> toDeleteInEngineThread;
     void doDeleteInEngineThread();
+
+    void cleanupScarceResources();
 };
 
+/*
+   This function should be called prior to evaluation of any js expression,
+   so that scarce resources are not freed prematurely (eg, if there is a
+   nested javascript expression).
+ */
+inline void QQmlEnginePrivate::referenceScarceResources()
+{
+    scarceResourcesRefCount += 1;
+}
+
+/*
+   This function should be called after evaluation of the js expression is
+   complete, and so the scarce resources may be freed safely.
+ */
+inline void QQmlEnginePrivate::dereferenceScarceResources()
+{
+    Q_ASSERT(scarceResourcesRefCount > 0);
+    scarceResourcesRefCount -= 1;
+
+    // if the refcount is zero, then evaluation of the "top level"
+    // expression must have completed.  We can safely release the
+    // scarce resources.
+    if (Q_LIKELY(scarceResourcesRefCount == 0)) {
+        QV4::ExecutionEngine *engine = QV8Engine::getV4(v8engine());
+        if (Q_UNLIKELY(!engine->scarceResources.isEmpty())) {
+            cleanupScarceResources();
+        }
+    }
+}
+
 /*!
 Returns true if the calling thread is the QQmlEngine thread.
 */
@@ -373,7 +407,7 @@ const QQmlEnginePrivate *QQmlEnginePrivate::get(const QQmlEngine *e)
 {
     Q_ASSERT(e);
 
-    return e->d_func();
+    return e ? e->d_func() : nullptr;
 }
 
 QQmlEnginePrivate *QQmlEnginePrivate::get(QQmlContext *c)
@@ -403,19 +437,6 @@ QQmlEnginePrivate *QQmlEnginePrivate::get(QV4::ExecutionEngine *e)
     return get(qmlEngine);
 }
 
-void QQmlEnginePrivate::setDebugChangesCache(const QHash<QUrl, QByteArray> &changes)
-{
-    Locker locker(this);
-    foreach (const QUrl &key, changes.keys())
-        debugChangesHash.insert(key, changes.value(key));
-}
-
-QHash<QUrl, QByteArray> QQmlEnginePrivate::debugChangesCache()
-{
-    Locker locker(this);
-    return debugChangesHash;
-}
-
 QT_END_NAMESPACE
 
 #endif // QQMLENGINE_P_H