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Diffstat (limited to 'doc/src/snippets/qml/integrating-javascript/scarceresources/avatarExample.cpp')
-rw-r--r-- | doc/src/snippets/qml/integrating-javascript/scarceresources/avatarExample.cpp | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/doc/src/snippets/qml/integrating-javascript/scarceresources/avatarExample.cpp b/doc/src/snippets/qml/integrating-javascript/scarceresources/avatarExample.cpp new file mode 100644 index 0000000000..e018a68292 --- /dev/null +++ b/doc/src/snippets/qml/integrating-javascript/scarceresources/avatarExample.cpp @@ -0,0 +1,124 @@ +/**************************************************************************** +** +** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies). +** Contact: http://www.qt-project.org/ +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:BSD$ +** You may use this file under the terms of the BSD license as follows: +** +** "Redistribution and use in source and binary forms, with or without +** modification, are permitted provided that the following conditions are +** met: +** * Redistributions of source code must retain the above copyright +** notice, this list of conditions and the following disclaimer. +** * Redistributions in binary form must reproduce the above copyright +** notice, this list of conditions and the following disclaimer in +** the documentation and/or other materials provided with the +** distribution. +** * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor +** the names of its contributors may be used to endorse or promote +** products derived from this software without specific prior written +** permission. +** +** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "avatarExample.h" +#include <QQmlEngine> +#include <QQmlComponent> + +void registerTypes() +{ +//![0] + qmlRegisterType<AvatarExample>("Qt.example", 1, 0, "AvatarExample"); +//![0] +} + +void expectOne() +{ +//![1] +QQmlComponent component(&engine, "exampleOne.qml"); +QObject *object = component.create(); +// The scarce resource will have been released automatically +// by this point, after the binding expression was evaluated. +delete object; +//![1] +} + +void expectTwo() +{ +//![2] +QQmlComponent component(&engine, "exampleTwo.qml"); +QObject *object = component.create(); +// The scarce resource will not have been released automatically +// after the binding expression was evaluated. +// Since the scarce resource was not released explicitly prior +// to the binding expression being evaluated, we get: +bool expectedResult = (object->property("avatar").isValid() == true); +delete object; +//![2] +} + +void expectThree() +{ +//![3] +QQmlComponent component(&engine, "exampleThree.qml"); +QObject *object = component.create(); +// The resource was preserved explicitly during evaluation of the +// JavaScript expression. Thus, during property assignment, the +// scarce resource was still valid, and so we get: +bool expectedResult = (object->property("avatar").isValid() == true); +// The scarce resource will not be released until all references to +// the resource are released, and the JavaScript garbage collector runs. +delete object; +//![3] +} + +void expectFour() +{ +//![4] +QQmlComponent component(&engine, "exampleFour.qml"); +QObject *object = component.create(); +// The scarce resource was explicitly preserved by the client during +// the importAvatar() function, and so the scarce resource +// remains valid until the explicit call to releaseAvatar(). As such, +// we get the expected results: +bool expectedResultOne = (object->property("avatarOne").isValid() == true); +bool expectedResultTwo = (object->property("avatarTwo").isValid() == false); +// Because the scarce resource referenced by avatarTwo was released explicitly, +// it will no longer be consuming any system resources (beyond what a normal +// JS Object would; that small overhead will exist until the JS GC runs, as per +// any other JavaScript object). +delete object; +//![4] +} + +void expectFive() +{ +//![5] +QQmlComponent component(&engine, "exampleFive.qml"); +QObject *object = component.create(); +// We have the expected results: +bool expectedResultOne = (object->property("avatarOne").isValid() == false); +bool expectedResultTwo = (object->property("avatarTwo").isValid() == false); +// Because although only avatarTwo was explicitly released, +// avatarOne and avatarTwo were referencing the same +// scarce resource. +delete object; +//![5] +} |