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Diffstat (limited to 'src/declarative/qml/qdeclarativescarceresourcescriptclass_p.h')
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diff --git a/src/declarative/qml/qdeclarativescarceresourcescriptclass_p.h b/src/declarative/qml/qdeclarativescarceresourcescriptclass_p.h new file mode 100644 index 0000000000..2a1390a230 --- /dev/null +++ b/src/declarative/qml/qdeclarativescarceresourcescriptclass_p.h @@ -0,0 +1,163 @@ +/**************************************************************************** +** +** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies). +** All rights reserved. +** Contact: Nokia Corporation (qt-info@nokia.com) +** +** This file is part of the QtDeclarative module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the Technology Preview License Agreement accompanying +** this package. +** +** 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 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain additional +** rights. These rights are described in the Nokia Qt LGPL Exception +** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. +** +** If you have questions regarding the use of this file, please contact +** Nokia at qt-info@nokia.com. +** +** +** +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#ifndef QDECLARATIVESCARCERESOURCESCRIPTCLASS_P_H +#define QDECLARATIVESCARCERESOURCESCRIPTCLASS_P_H + +// +// W A R N I N G +// ------------- +// +// This file is not part of the Qt API. It exists purely as an +// implementation detail. This header file may change from version to +// version without notice, or even be removed. +// +// We mean it. +// + +#include "private/qdeclarativepropertycache_p.h" +#include "private/qdeclarativetypenamecache_p.h" + +#include <private/qscriptdeclarativeclass_p.h> +#include <QtScript/qscriptengine.h> + +QT_BEGIN_NAMESPACE + +class QDeclarativeEngine; + +/* + Scarce resources (like pixmaps and textures) are managed manually + in that the variant will be set to the invalid variant once the + JavaScript engine has finished using the JavaScript object whose + instance data is the ScarceResourceData (but before the garbage + collector frees the JavaScript object itself). + + The engine stores a doubly-linked-list of scarce resources which + will to be cleaned up after a binding is successfully evaluated + (unless the user explicitly preserves the scarce resource). + + A ScarceResourceData pointer should not be deleted manually, as + all instances of a ScarceResourceData should be owned by the + JavaScript engine. + */ +struct ScarceResourceData : public QScriptDeclarativeClass::Object { + ScarceResourceData(const QVariant &v) : resource(v), prev(0), next(0) + { + } + + virtual ~ScarceResourceData() + { + releaseResource(); + } + + // Insert this resource into the given list of resources. + void insertInto(ScarceResourceData **list) + { + // This node becomes the head of the list. + next = *list; // so our next = old list head + *list = this; // list now points to us (we're the head) + prev = list; // as we're the head, our prev ptr becomes the list ptr. + + // and the next node's prev pointer must contain a ptr to our next ptr, + // since per definition, prev always contains a pointer to the previous node's "next" ptr, + // and the "this" node is the "this->next" node's "prev" node. + if (next) next->prev = &next; + } + + // Remove this resource from the list of resources, without releasing the resource. + void removeNode() + { + // whatever previously pointed to this node (ie, as that node's "next" node) + // should now point to our next node (since we no longer exist in the list). + // and the next node's prev ptr should point to our prev node. + if (prev) *prev = next; + if (next) next->prev = prev; + prev = 0; + next = 0; + } + + // Release this resource, and remove from the list. + void releaseResource() + { + resource = QVariant(); + removeNode(); + } + + QVariant resource; + + // prev always contains a pointer to the previous node's "next" ptr. + // :. for the head node, [*prev] will be engine->scarceResources + // :. for every other node, [*prev] will be the previous node's "next" ptr. + ScarceResourceData **prev; + ScarceResourceData *next; +}; + +class Q_AUTOTEST_EXPORT QDeclarativeScarceResourceScriptClass : public QScriptDeclarativeClass +{ +public: + QDeclarativeScarceResourceScriptClass(QDeclarativeEngine *); + ~QDeclarativeScarceResourceScriptClass(); + + // Creates a new JavaScript object whose instance data is the scarce resource v + QScriptValue newScarceResource(const QVariant &v); + + // inherited from QScriptDeclarativeClass + virtual QScriptClass::QueryFlags queryProperty(Object *, const Identifier &, + QScriptClass::QueryFlags flags); + virtual Value property(Object *, const Identifier &); + virtual QVariant toVariant(Object *, bool *ok = 0); + QVariant toVariant(const QScriptValue &value); + +private: + PersistentIdentifier m_preserveId; + PersistentIdentifier m_destroyId; + QScriptValue m_preserve; + QScriptValue m_destroy; + + static QScriptValue preserve(QScriptContext *context, QScriptEngine *engine); + static QScriptValue destroy(QScriptContext *context, QScriptEngine *engine); + + QDeclarativeEngine *engine; +}; + +QT_END_NAMESPACE + +#endif // QDECLARATIVESCARCERESOURCESCRIPTCLASS_P_H |