From a129444bb0156c936900dbd2f12bd9f427ff366c Mon Sep 17 00:00:00 2001 From: Qt by Nokia Date: Wed, 27 Apr 2011 14:13:26 +0200 Subject: Initial import from qtquick2. Branched from the monolithic repo, Qt qtquick2 branch, at commit a4a585d2ee907746682846ae6e8a48e19deef469 --- .../qml/qdeclarativescarceresourcescriptclass.cpp | 193 +++++++++++++++++++++ 1 file changed, 193 insertions(+) create mode 100644 src/declarative/qml/qdeclarativescarceresourcescriptclass.cpp (limited to 'src/declarative/qml/qdeclarativescarceresourcescriptclass.cpp') diff --git a/src/declarative/qml/qdeclarativescarceresourcescriptclass.cpp b/src/declarative/qml/qdeclarativescarceresourcescriptclass.cpp new file mode 100644 index 0000000000..121d0a1a35 --- /dev/null +++ b/src/declarative/qml/qdeclarativescarceresourcescriptclass.cpp @@ -0,0 +1,193 @@ +/**************************************************************************** +** +** 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. +** +** +** +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "private/qdeclarativescarceresourcescriptclass_p.h" + +#include "private/qdeclarativeengine_p.h" +#include "private/qdeclarativecontext_p.h" +#include "private/qdeclarativedata_p.h" +#include "private/qdeclarativetypenamescriptclass_p.h" +#include "private/qdeclarativelistscriptclass_p.h" +#include "private/qdeclarativebinding_p.h" +#include "private/qdeclarativeguard_p.h" +#include "private/qdeclarativevmemetaobject_p.h" + +#include +#include +#include + +Q_DECLARE_METATYPE(QScriptValue); + +QT_BEGIN_NAMESPACE + +QDeclarativeScarceResourceScriptClass::QDeclarativeScarceResourceScriptClass(QDeclarativeEngine *bindEngine) + : QScriptDeclarativeClass(QDeclarativeEnginePrivate::getScriptEngine(bindEngine)), engine(bindEngine) +{ + QScriptEngine *scriptEngine = QDeclarativeEnginePrivate::getScriptEngine(engine); + + // Properties of this type can be explicitly preserved by clients, + // which prevents the scarce resource from being automatically + // released after the binding has been evaluated. + m_preserve = scriptEngine->newFunction(preserve); + m_preserveId = createPersistentIdentifier(QLatin1String("preserve")); + + // Similarly, they can be explicitly destroyed by clients, + // which releases the scarce resource. + m_destroy = scriptEngine->newFunction(destroy); + m_destroyId = createPersistentIdentifier(QLatin1String("destroy")); +} + +QDeclarativeScarceResourceScriptClass::~QDeclarativeScarceResourceScriptClass() +{ +} + +/* + Returns a JavaScript object whose instance data is a new scarce resource data. + The scarce resource is added to the doubly-linked-list of scarce resources in the engine + so that the scarce resource can be released after evaluation completes. + */ +QScriptValue QDeclarativeScarceResourceScriptClass::newScarceResource(const QVariant &v) +{ + // create the scarce resource + ScarceResourceData *srd = new ScarceResourceData(v); + + // insert into the linked list + QDeclarativeEnginePrivate *enginePrivate = QDeclarativeEnginePrivate::get(engine); + srd->insertInto(&enginePrivate->scarceResources); + Q_ASSERT(enginePrivate->scarceResourcesRefCount > 0); + + // return the javascript object with the scarce resource instance data + QScriptEngine *scriptEngine = QDeclarativeEnginePrivate::getScriptEngine(engine); + return QScriptDeclarativeClass::newObject(scriptEngine, this, srd); // JSC takes ownership of srd. +} + +QVariant QDeclarativeScarceResourceScriptClass::toVariant(Object *object, bool *ok) +{ + ScarceResourceData *obj = static_cast(object); + if (ok) *ok = true; + return obj->resource; +} + +QVariant QDeclarativeScarceResourceScriptClass::toVariant(const QScriptValue &value) +{ + Q_ASSERT(scriptClass(value) == this); + + return toVariant(object(value), 0); +} + +// The destroy() and preserve() function properties are readable. +QScriptClass::QueryFlags +QDeclarativeScarceResourceScriptClass::queryProperty(Object *object, const Identifier &name, + QScriptClass::QueryFlags flags) +{ + Q_UNUSED(object) + Q_UNUSED(flags) + + if (name == m_destroyId.identifier || name == m_preserveId.identifier) + return (QScriptClass::HandlesReadAccess); + return 0; +} + +// Return the (function) values which may be evaluated by clients. +QDeclarativeScarceResourceScriptClass::Value +QDeclarativeScarceResourceScriptClass::property(Object *object, const Identifier &name) +{ + Q_UNUSED(object) + + QScriptEngine *scriptEngine = QDeclarativeEnginePrivate::getScriptEngine(engine); + + // functions + if (name == m_preserveId.identifier) + return Value(scriptEngine, m_preserve); + else if (name == m_destroyId.identifier) + return Value(scriptEngine, m_destroy); + + return Value(); +} + +/* + The user explicitly wants to preserve the resource. + We remove the scarce resource from the engine's linked list + of resources to release after evaluation completes. + */ +QScriptValue QDeclarativeScarceResourceScriptClass::preserve(QScriptContext *context, QScriptEngine *engine) +{ + QDeclarativeEnginePrivate *p = QDeclarativeEnginePrivate::get(engine); + QScriptValue that = context->thisObject(); + + if (scriptClass(that) != p->scarceResourceClass) + return engine->undefinedValue(); + + // The client wishes to preserve the resource in this SRD. + ScarceResourceData *data = static_cast(p->scarceResourceClass->object(that)); + if (!data) + return engine->undefinedValue(); + + // remove node from list, without releasing the resource. + data->removeNode(); + + return engine->undefinedValue(); +} + +/* + The user explicitly wants to release the resource. + We set the internal scarce resource variant to the invalid variant. + */ +QScriptValue QDeclarativeScarceResourceScriptClass::destroy(QScriptContext *context, QScriptEngine *engine) +{ + QDeclarativeEnginePrivate *p = QDeclarativeEnginePrivate::get(engine); + QScriptValue that = context->thisObject(); + + if (scriptClass(that) != p->scarceResourceClass) + return engine->undefinedValue(); + + // the client wishes to release the resource in this SRD. + ScarceResourceData *data = static_cast(p->scarceResourceClass->object(that)); + if (!data) + return engine->undefinedValue(); + + // release the resource and remove the node from the list. + data->releaseResource(); + + return engine->undefinedValue(); +} + +QT_END_NAMESPACE -- cgit v1.2.3 From 4ff72975b6501a0003329bb8183479d4df5eda4d Mon Sep 17 00:00:00 2001 From: Chris Adams Date: Tue, 10 May 2011 12:10:06 +1000 Subject: Add user documentation for scarce resource properties Relates to commit 59ace5c5a666b1588560d2aeaa79a57da535e863. Task-number: QMLNG-18 Reviewed-by: Aaron Kennedy Change-Id: I216ced4c663ebab8003978999dc16ac809443a5f --- .../qml/qdeclarativescarceresourcescriptclass.cpp | 36 +++++++++++++++++++--- 1 file changed, 31 insertions(+), 5 deletions(-) (limited to 'src/declarative/qml/qdeclarativescarceresourcescriptclass.cpp') diff --git a/src/declarative/qml/qdeclarativescarceresourcescriptclass.cpp b/src/declarative/qml/qdeclarativescarceresourcescriptclass.cpp index 121d0a1a35..d94e2d9332 100644 --- a/src/declarative/qml/qdeclarativescarceresourcescriptclass.cpp +++ b/src/declarative/qml/qdeclarativescarceresourcescriptclass.cpp @@ -144,9 +144,22 @@ QDeclarativeScarceResourceScriptClass::property(Object *object, const Identifier } /* - The user explicitly wants to preserve the resource. - We remove the scarce resource from the engine's linked list - of resources to release after evaluation completes. + This method is called when the user explicitly calls the "preserve" method of a scarce resource in JavaScript + within the specified evaluation context \a context of the script engine \a engine. + Calling this function signifies that the user explicitly wants to preserve the resource rather than let it + be automatically released once evaluation of the expression is complete. + This function removes the internal scarce resource from the declarative engine's linked list of scarce resources + to release after evaluation of the expression completes. This means that the resource will only be truly + released when the JavaScript engine's garbage collector is run. + + Example: + \qml + function getIcon(model) { + var icon = model.avatar; // a pixmap property + icon.preserve(); // explicitly preserves the resource + return icon; // a valid variant will be returned + } + \endqml */ QScriptValue QDeclarativeScarceResourceScriptClass::preserve(QScriptContext *context, QScriptEngine *engine) { @@ -168,8 +181,21 @@ QScriptValue QDeclarativeScarceResourceScriptClass::preserve(QScriptContext *con } /* - The user explicitly wants to release the resource. - We set the internal scarce resource variant to the invalid variant. + This method is called when the user explicitly calls the "destroy" method of a scarce resource in JavaScript + within the specified evaluation context \a context of the script engine \a engine. + Calling this function signifies that the user explicitly wants to release the resource. + This function sets the internal scarce resource variant to the invalid variant, in order to release the original resource, + and then removes the resource from the declarative engine's linked-list of scarce resources to + to release after evaluation of the expression completes, as it has already been released. + + Example: + \qml + function getIcon(model) { + var icon = model.avatar; // a pixmap property + icon.destroy(); // explicitly releases the resource + return icon; // an invalid variant will be returned + } + \endqml */ QScriptValue QDeclarativeScarceResourceScriptClass::destroy(QScriptContext *context, QScriptEngine *engine) { -- cgit v1.2.3