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Diffstat (limited to 'doc/src/snippets/xml/rsslisting/handler.cpp')
-rw-r--r-- | doc/src/snippets/xml/rsslisting/handler.cpp | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/doc/src/snippets/xml/rsslisting/handler.cpp b/doc/src/snippets/xml/rsslisting/handler.cpp new file mode 100644 index 0000000000..fe9ef5cbe9 --- /dev/null +++ b/doc/src/snippets/xml/rsslisting/handler.cpp @@ -0,0 +1,182 @@ +/**************************************************************************** +** +** 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 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." +** $QT_END_LICENSE$ +** +****************************************************************************/ + +/* +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] +bool Handler::fatalError (const QXmlParseException & exception) +{ + qWarning() << "Fatal error on line" << exception.lineNumber() + << ", column" << exception.columnNumber() << ":" + << exception.message(); + + return false; +} +//! [0] |