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// Copyright (C) 2019 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
#include "xmlutils_libxslt.h"
#include "xmlutils.h"
#include "qtcompat.h"
#include <QtCore/QByteArray>
#include <QtCore/QCoreApplication>
#include <QtCore/QDir>
#include <QtCore/QFile>
#include <QtCore/QString>
#include <libxslt/xsltutils.h>
#include <libxslt/transform.h>
#include <libxml/xmlsave.h>
#include <libxml/xpath.h>
#include <cstdlib>
#include <memory>
using namespace Qt::StringLiterals;
static void cleanup()
{
xsltCleanupGlobals();
xmlCleanupParser();
}
static void ensureInitialized()
{
static bool initialized = false;
if (!initialized) {
initialized = true;
xmlInitParser();
xsltInit();
qAddPostRoutine(cleanup);
}
}
// RAI Helpers for cleaning up libxml2/libxslt data
struct XmlDocDeleter // for std::unique_ptr<xmlDoc>
{
void operator()(xmlDocPtr xmlDoc) { xmlFreeDoc(xmlDoc); }
};
struct XmlXPathObjectDeleter
{
void operator()(xmlXPathObjectPtr xPathObject) { xmlXPathFreeObject(xPathObject); }
};
struct XmlStyleSheetDeleter // for std::unique_ptr<xsltStylesheet>
{
void operator()(xsltStylesheetPtr xslt) { xsltFreeStylesheet(xslt); }
};
struct XmlXPathContextDeleter
{
void operator()(xmlXPathContextPtr xPathContext) { xmlXPathFreeContext(xPathContext); }
};
using XmlDocUniquePtr = std::unique_ptr<xmlDoc, XmlDocDeleter>;
using XmlPathObjectUniquePtr = std::unique_ptr<xmlXPathObject, XmlXPathObjectDeleter>;
using XmlStyleSheetUniquePtr = std::unique_ptr<xsltStylesheet, XmlStyleSheetDeleter>;
using XmlXPathContextUniquePtr = std::unique_ptr<xmlXPathContext, XmlXPathContextDeleter>;
// Helpers for formatting nodes obtained from XPATH queries
static int qbXmlOutputWriteCallback(void *context, const char *buffer, int len)
{
static_cast<QByteArray *>(context)->append(buffer, len);
return len;
}
static int qbXmlOutputCloseCallback(void * /* context */) { return 0; }
static QByteArray formatNode(xmlNodePtr node, QString *errorMessage)
{
QByteArray result;
xmlSaveCtxtPtr saveContext =
xmlSaveToIO(qbXmlOutputWriteCallback, qbXmlOutputCloseCallback,
&result, "UTF-8", 0);
if (!saveContext) {
*errorMessage = u"xmlSaveToIO() failed."_s;
return result;
}
const long saveResult = xmlSaveTree(saveContext, node);
xmlSaveClose(saveContext);
if (saveResult < 0)
*errorMessage = u"xmlSaveTree() failed."_s;
return result;
}
// XPath expressions
class LibXmlXQuery : public XQuery
{
public:
explicit LibXmlXQuery(XmlDocUniquePtr &doc, XmlXPathContextUniquePtr &xpathContext) :
m_doc(std::move(doc)), m_xpathContext(std::move(xpathContext))
{
ensureInitialized();
}
protected:
QString doEvaluate(const QString &xPathExpression, QString *errorMessage) override;
private:
XmlDocUniquePtr m_doc;
XmlXPathContextUniquePtr m_xpathContext;
};
QString LibXmlXQuery::doEvaluate(const QString &xPathExpression, QString *errorMessage)
{
const QByteArray xPathExpressionB = xPathExpression.toUtf8();
auto xPathExpressionX = reinterpret_cast<const xmlChar *>(xPathExpressionB.constData());
XmlPathObjectUniquePtr xPathObject(xmlXPathEvalExpression(xPathExpressionX, m_xpathContext.get()));
if (!xPathObject) {
*errorMessage = u"xmlXPathEvalExpression() failed for \""_s + xPathExpression
+ u'"';
return QString();
}
QString result;
if (xmlNodeSetPtr nodeSet = xPathObject->nodesetval) {
for (int n = 0, count = nodeSet->nodeNr; n < count; ++n) {
auto node = nodeSet->nodeTab[n];
if (node->type == XML_ELEMENT_NODE) {
result += QString::fromLocal8Bit(formatNode(node, errorMessage));
if (!errorMessage->isEmpty())
return QString();
}
}
}
return result;
}
std::shared_ptr<XQuery> libXml_createXQuery(const QString &focus, QString *errorMessage)
{
XmlDocUniquePtr doc(xmlReadFile(QFile::encodeName(focus).constData(),
"utf-8", XML_PARSE_NOENT));
if (!doc) {
*errorMessage = u"libxml2: Cannot set focus to "_s + QDir::toNativeSeparators(focus);
return {};
}
XmlXPathContextUniquePtr xpathContext(xmlXPathNewContext(doc.get()));
if (!xpathContext) {
*errorMessage = u"libxml2: xmlXPathNewContext() failed"_s;
return {};
}
return std::shared_ptr<XQuery>(new LibXmlXQuery(doc, xpathContext));
}
// XSLT transformation
static constexpr auto xsltPrefix = R"(<?xml version="1.0" encoding="UTF-8" ?>
<xsl:transform version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
)"_L1;
QString libXslt_transform(const QString &xml, QString xsl, QString *errorMessage)
{
ensureInitialized();
// Read XML data
if (!xsl.startsWith(u"<?xml")) {
xsl.prepend(xsltPrefix);
xsl.append(u"</xsl:transform>"_s);
}
const QByteArray xmlData = xml.toUtf8();
XmlDocUniquePtr xmlDoc(xmlReadMemory(xmlData.constData(), int(xmlData.size()),
"", "utf-8", XML_PARSE_NOENT));
if (!xmlDoc) {
*errorMessage = u"xmlParseMemory() failed for XML."_s;
return xml;
}
// Read XSL data as a XML file
const QByteArray xslData = xsl.toUtf8();
// xsltFreeStylesheet will delete this pointer
xmlDocPtr xslDoc = xmlParseMemory(xslData.constData(), xslData.size());
if (!xslDoc) {
*errorMessage = u"xmlParseMemory() failed for XSL \""_s + xsl + u"\"."_s;
return xml;
};
// Parse XSL data
XmlStyleSheetUniquePtr xslt(xsltParseStylesheetDoc(xslDoc));
if (!xslt) {
*errorMessage = u"xsltParseStylesheetDoc() failed."_s;
return xml;
}
// Apply XSL
XmlDocUniquePtr xslResult(xsltApplyStylesheet(xslt.get(), xmlDoc.get(), nullptr));
xmlChar *buffer = nullptr;
int bufferSize;
QString result;
if (xsltSaveResultToString(&buffer, &bufferSize, xslResult.get(), xslt.get()) == 0) {
result = QString::fromUtf8(reinterpret_cast<char*>(buffer), bufferSize);
std::free(buffer);
} else {
*errorMessage = u"xsltSaveResultToString() failed."_s;
result = xml;
}
return result.trimmed();
}
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