XMLDocument.cc

Go to the documentation of this file.

#include <assert.h>
#include <iostream>
#include <iomanip>
#include <sstream>
#include <memory>
#include <string>
#include <cstdio>
#include <stdio.h>
#include <ext/stdio_filebuf.h>

#include "FWCore/Concurrency/interface/Xerces.h"
#include <xercesc/util/XMLString.hpp>
#include <xercesc/util/XMLUni.hpp>
#include <xercesc/util/BinInputStream.hpp>
#include <xercesc/dom/DOM.hpp>
#include <xercesc/dom/DOMImplementationLS.hpp>
#include <xercesc/dom/DOMLSSerializer.hpp>
#include <xercesc/framework/LocalFileFormatTarget.hpp>
#include <xercesc/parsers/XercesDOMParser.hpp>
#include <xercesc/sax/InputSource.hpp>
#include <xercesc/sax/HandlerBase.hpp>


#include "FWCore/Utilities/interface/Exception.h"

#include "PhysicsTools/MVATrainer/interface/XMLSimpleStr.h"
#include "PhysicsTools/MVATrainer/interface/XMLUniStr.h"
#include "PhysicsTools/MVATrainer/interface/XMLDocument.h"

XERCES_CPP_NAMESPACE_USE

unsigned int XMLDocument::XercesPlatform::instances = 0;

namespace { // anonymous
    struct DocReleaser {
        inline DocReleaser(DOMDocument *doc) : doc(doc) {}
        inline ~DocReleaser() { doc->release(); }

        DOMDocument *doc;
    };

    template<typename T>
    class XMLInputSourceWrapper :
        public XERCES_CPP_NAMESPACE_QUALIFIER InputSource {
        public:
        typedef typename T::Stream_t Stream_t;

        XMLInputSourceWrapper(std::unique_ptr<Stream_t>& obj) : obj(obj) {}
        virtual ~XMLInputSourceWrapper() {}

        virtual XERCES_CPP_NAMESPACE_QUALIFIER BinInputStream*
                            makeStream() const override
        { return new T(*obj); }

        private:
        std::unique_ptr<Stream_t>&  obj;
    };

    class STLInputStream :
            public XERCES_CPP_NAMESPACE_QUALIFIER BinInputStream {
        public:
            typedef std::istream Stream_t;

            STLInputStream(std::istream &in) : in(in) {}
            virtual ~STLInputStream() {}

            virtual XMLFilePos curPos() const override { return pos; }

            virtual XMLSize_t readBytes(XMLByte *const buf,
                        const XMLSize_t size) override;
      
            virtual const XMLCh* getContentType() const override { return 0; }

        private:
            std::istream    &in;
            unsigned int    pos;
    };

    template<int (*close)(FILE*)>
    class stdio_istream : public std::istream {
        public:
        typedef __gnu_cxx::stdio_filebuf<char>  __filebuf_type;
        typedef stdio_istream<close>        __istream_type;

        stdio_istream(FILE *file) :
            file_(file), filebuf_(file, std::ios_base::in)
        { this->init(&filebuf_); }

        ~stdio_istream()
        { close(file_); }

        __filebuf_type *rdbuf() const
        { return const_cast<__filebuf_type*>(&filebuf_); }

        private:
        FILE        *file_;
        __filebuf_type  filebuf_;
    };

    typedef XMLInputSourceWrapper<STLInputStream> STLInputSource;
} // anonymous namespace

XMLSize_t STLInputStream::readBytes(XMLByte* const buf,
                    const XMLSize_t size)
{
    char *rawBuf = reinterpret_cast<char*>(buf);
    unsigned int bytes = size * sizeof(XMLByte);
    in.read(rawBuf, bytes);
    unsigned int readBytes = in.gcount();

    if (in.bad())
        throw cms::Exception("XMLDocument")
            << "I/O stream bad in STLInputStream::readBytes()"
            << std::endl;

    unsigned int read = (unsigned int)(readBytes / sizeof(XMLByte));
    unsigned int rest = (unsigned int)(readBytes % sizeof(XMLByte));
    for(unsigned int i = 1; i <= rest; i++)
        in.putback(rawBuf[readBytes - i]);

    pos += read;
    return read;
}

XMLDocument::XercesPlatform::XercesPlatform()
{
    if (!instances++) {
        try {
            cms::concurrency::xercesInitialize();
        } catch(const XMLException &e) {
            throw cms::Exception("XMLDocument")
                << "cms::concurrency::xercesInitialize failed "
                   "because of: "
                << XMLSimpleStr(e.getMessage()) << std::endl;
        }
    }
}

XMLDocument::XercesPlatform::~XercesPlatform()
{
    if (!--instances)
        cms::concurrency::xercesTerminate();
}

XMLDocument::XMLDocument(const std::string &fileName, bool write) :
    platform(new XercesPlatform()), fileName(fileName),
    write(write), impl(0), doc(0), rootNode(0)
{
    if (write)
        openForWrite(fileName);
    else {
        std::unique_ptr<std::istream> inputStream(
                    new std::ifstream(fileName.c_str()));
        if (!inputStream->good())
            throw cms::Exception("XMLDocument")
                << "XML input file \"" << fileName << "\" "
                   "could not be opened for reading."
                << std::endl;
        openForRead(inputStream);
    }
}

XMLDocument::XMLDocument(const std::string &fileName,
                         const std::string &command) :
    platform(new XercesPlatform()), fileName(fileName),
    write(false), impl(0), doc(0), rootNode(0)
{
    FILE *file = popen(command.c_str(), "r");
    if (!file)
        throw cms::Exception("XMLDocument")
            << "Could not execute XML preprocessing "
               " command \"" << command << "\"."
            << std::endl;

    std::unique_ptr<std::istream> inputStream(
                    new stdio_istream<pclose>(file));
    if (!inputStream->good())
        throw cms::Exception("XMLDocument")
            << "XML preprocessing command \"" << fileName
            << "\" stream could not be opened for reading."
            << std::endl;

    openForRead(inputStream);
}

XMLDocument::~XMLDocument()
{
    if (!write)
        return;

    std::unique_ptr<DocReleaser> docReleaser(new DocReleaser(doc));

    std::unique_ptr<DOMLSSerializer> writer(((DOMImplementationLS*)impl)->createLSSerializer());
    assert(writer.get());

    if( writer->getDomConfig()->canSetParameter(XMLUni::fgDOMWRTDiscardDefaultContent,true))
      writer->getDomConfig()->setParameter(XMLUni::fgDOMWRTDiscardDefaultContent,true);
    if( writer->getDomConfig()->canSetParameter(XMLUni::fgDOMWRTFormatPrettyPrint, true))
      writer->getDomConfig()->setParameter(XMLUni::fgDOMWRTFormatPrettyPrint, true);

    std::unique_ptr<DOMLSOutput> outputDesc(((DOMImplementationLS*)impl)->createLSOutput());
    assert(outputDesc.get());
    outputDesc->setEncoding(XMLUniStr("UTF-8"));
    
    try {
        std::unique_ptr<XMLFormatTarget> target(
                new LocalFileFormatTarget(fileName.c_str()));
        outputDesc->setByteStream(target.get());
        writer->write( doc, outputDesc.get());
    } catch(...) {
        std::remove(fileName.c_str());
    }
}

void XMLDocument::openForRead(std::unique_ptr<std::istream> &stream)
{
    parser.reset(new XercesDOMParser());
    parser->setValidationScheme(XercesDOMParser::Val_Auto);
    parser->setDoNamespaces(false);
    parser->setDoSchema(false);
    parser->setValidationSchemaFullChecking(false);
    errHandler.reset(new HandlerBase());
    parser->setErrorHandler(errHandler.get());
    parser->setCreateEntityReferenceNodes(false);

    inputSource.reset(new STLInputSource(stream));

    try {
        parser->parse(*inputSource);
        if (parser->getErrorCount())
            throw cms::Exception("XMLDocument")
                << "XML parser reported errors."
                << std::endl;
    } catch(const XMLException &e) {
        throw cms::Exception("XMLDocument")
            << "XML parser reported DOM error no. "
            << (unsigned long)e.getCode()
            << ": " << XMLSimpleStr(e.getMessage()) << "."
            << std::endl;
    } catch(const SAXException &e) {
        throw cms::Exception("XMLDocument")
            << "XML parser reported: "
            << XMLSimpleStr(e.getMessage()) << "."
            << std::endl;
    }

    doc = parser->getDocument();

    DOMNode *node = doc->getFirstChild();
    while(node && node->getNodeType() != DOMNode::ELEMENT_NODE)
        node = node->getNextSibling();

    if (!node)
        throw cms::Exception("XMLDocument")
            << "XML document didn't contain a valid "
            << "root node." << std::endl;

    rootNode = static_cast<DOMElement*>(node);
}

void XMLDocument::openForWrite(const std::string &fileName)
{
    impl = DOMImplementationRegistry::getDOMImplementation(
                            XMLUniStr("LS"));
    assert(impl);
}

DOMDocument *XMLDocument::createDocument(const std::string &root)
{
    if (doc)
        throw cms::Exception("XMLDocument")
            << "Document already exists in createDocument."
            << std::endl;

    doc = impl->createDocument(0, XMLUniStr(root.c_str()), 0);
    rootNode = doc->getDocumentElement();

    return doc;
}

// specialization of read/write method templates for bool

static bool isBool(std::string value)
{
    for(unsigned int i = 0; i < value.size(); i++)
        if (value[i] >= 'A' && value[i] <= 'Z')
            value[i] += 'a' - 'A';

    if (value == "1" || value == "y" || value == "yes" ||
        value == "true" || value == "ok")
        return true;

    if (value == "0" || value == "n" || value == "no" || value == "false")
        return false;

    throw cms::Exception("XMLDocument")
        << "Invalid boolean value in XML document" << std::endl;
}

static const char *makeBool(bool value)
{
    return value ? "true" : "false";
}

bool XMLDocument::hasAttribute(XERCES_CPP_NAMESPACE_QUALIFIER DOMElement *elem,
                               const char *name)
{
    XMLUniStr uniName(name);
    return elem->hasAttribute(uniName);
}

template<>
bool XMLDocument::readAttribute(
            XERCES_CPP_NAMESPACE_QUALIFIER DOMElement *elem,
            const char *name)
{
    XMLUniStr uniName(name);
    if (!elem->hasAttribute(uniName))
        throw cms::Exception("MVAComputer")
            << "Missing attribute " << name << " in tag "
            << XMLSimpleStr(elem->getNodeName())
            << "." << std::endl;
    const XMLCh *attribute = elem->getAttribute(uniName);
    return isBool(XMLSimpleStr(attribute));
}

template<>
bool XMLDocument::readAttribute(
            XERCES_CPP_NAMESPACE_QUALIFIER DOMElement *elem,
            const char *name, const bool &defValue)
{
    XMLUniStr uniName(name);
    if (!elem->hasAttribute(uniName))
        return defValue;
    const XMLCh *attribute = elem->getAttribute(uniName);
    return isBool(XMLSimpleStr(attribute));
}

template<>
void XMLDocument::writeAttribute(
            XERCES_CPP_NAMESPACE_QUALIFIER DOMElement *elem,
            const char *name, const bool &value)
{
    elem->setAttribute(XMLUniStr(name), XMLUniStr(makeBool(value)));
}

template<>
bool XMLDocument::readContent(
            XERCES_CPP_NAMESPACE_QUALIFIER DOMNode *node)
{
    const XMLCh *content = node->getTextContent();
    return isBool(XMLSimpleStr(content));
}

template<>
void XMLDocument::writeContent(
            XERCES_CPP_NAMESPACE_QUALIFIER DOMNode *node,
            XERCES_CPP_NAMESPACE_QUALIFIER DOMDocument *doc,
            const bool &value)
{
    node->appendChild(doc->createTextNode(XMLUniStr(makeBool(value))));
}