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Diffstat (limited to 'doc/codesnippets/doc/src/snippets/xml/rsslisting/handler.cpp')
-rw-r--r-- | doc/codesnippets/doc/src/snippets/xml/rsslisting/handler.cpp | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/doc/codesnippets/doc/src/snippets/xml/rsslisting/handler.cpp b/doc/codesnippets/doc/src/snippets/xml/rsslisting/handler.cpp new file mode 100644 index 000000000..3ba8d34e7 --- /dev/null +++ b/doc/codesnippets/doc/src/snippets/xml/rsslisting/handler.cpp @@ -0,0 +1,179 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Nokia Corporation (qt-info@nokia.com) +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** Commercial Usage +** Licensees holding valid Qt Commercial licenses may use this file in +** accordance with the Qt Commercial License Agreement provided with the +** Software or, alternatively, in accordance with the terms contained in +** a written agreement between you and Nokia. +** +** 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 1.0, 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 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at http://www.qtsoftware.com/contact. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +/* +handler.cpp + +Provides a handler for processing XML elements found by the reader. + +The handler looks for <title> and <link> elements within <item> elements, +and records the text found within them. Link information stored within +rdf:about attributes of <item> elements is also recorded when it is +available. + +For each item found, a signal is emitted which specifies its title and +link information. This may be used by user interfaces for the purpose of +displaying items as they are read. +*/ + +#include <QtGui> + +#include "handler.h" + +/* + Reset the state of the handler to ensure that new documents are + read correctly. + + We return true to indicate that parsing should continue. +*/ + +bool Handler::startDocument() +{ + inItem = false; + inTitle = false; + inLink = false; + + return true; +} + +/* + Process each starting element in the XML document. + + Nested item, title, or link elements are not allowed, so we return false + if we encounter any of these. We also prohibit multiple definitions of + title strings. + + Link destinations are read by this function if they are specified as + attributes in item elements. + + For all cases not explicitly checked for, we return true to indicate that + the element is acceptable, and that parsing should continue. By doing + this, we can ignore elements in which we are not interested. +*/ + +bool Handler::startElement(const QString &, const QString &, + const QString & qName, const QXmlAttributes &attr) +{ + if (qName == "item") { + + if (inItem) + return false; + else { + inItem = true; + linkString = attr.value("rdf:about"); + } + } + else if (qName == "title") { + + if (inTitle) + return false; + else if (!titleString.isEmpty()) + return false; + else if (inItem) + inTitle = true; + } + else if (qName == "link") { + + if (inLink) + return false; + else if (inItem) + inLink = true; + } + + return true; +} + +/* + Process each ending element in the XML document. + + For recognized elements, we reset flags to ensure that we can read new + instances of these elements. If we have read an item element, emit a + signal to indicate that a new item is available for display. + + We return true to indicate that parsing should continue. +*/ + +bool Handler::endElement(const QString &, const QString &, + const QString & qName) +{ + if (qName == "title" && inTitle) + inTitle = false; + else if (qName == "link" && inLink) + inLink = false; + else if (qName == "item") { + if (!titleString.isEmpty() && !linkString.isEmpty()) + emit newItem(titleString, linkString); + inItem = false; + titleString = ""; + linkString = ""; + } + + return true; +} + +/* + Collect characters when reading the contents of title or link elements + when they occur within an item element. + + We return true to indicate that parsing should continue. +*/ + +bool Handler::characters (const QString &chars) +{ + if (inTitle) + titleString += chars; + else if (inLink) + linkString += chars; + + return true; +} + +/* + Report a fatal parsing error, and return false to indicate to the reader + that parsing should stop. +*/ + +//! [0] +def fatalError(self, exception): + qWarning("Fatal error on line %d, column %d:%s" % (exception.lineNumber(), exception.columnNumber(), exception.message()) + + return False +//! [0] |