llsdserialize_xml.cpp

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#include "linden_common.h"
#include "llsdserialize_xml.h"

#include <iostream>
#include <deque>

#include "apr-1/apr_base64.h"

extern "C"
{
#ifdef LL_STANDALONE
# include <expat.h>
#else
# include "expat/expat.h"
#endif
}

LLSDXMLFormatter::LLSDXMLFormatter()
{
}

// virtual
LLSDXMLFormatter::~LLSDXMLFormatter()
{
}

// virtual
S32 LLSDXMLFormatter::format(const LLSD& data, std::ostream& ostr, U32 options) const
{
        std::streamsize old_precision = ostr.precision(25);

        LLString post = "";
        if (options & LLSDFormatter::OPTIONS_PRETTY)
        {
                post = "\n";
        }
        ostr << "<llsd>" << post;
        S32 rv = format_impl(data, ostr, options, 1);
        ostr << "</llsd>\n";

        ostr.precision(old_precision);
        return rv;
}

S32 LLSDXMLFormatter::format_impl(const LLSD& data, std::ostream& ostr, U32 options, U32 level) const
{
        S32 format_count = 1;
        LLString pre = "";
        LLString post = "";

        if (options & LLSDFormatter::OPTIONS_PRETTY)
        {
                for (U32 i = 0; i < level; i++)
                {
                        pre += "    ";
                }
                post = "\n";
        }

        switch(data.type())
        {
        case LLSD::TypeMap:
                if(0 == data.size())
                {
                        ostr << pre << "<map />" << post;
                }
                else
                {
                        ostr << pre << "<map>" << post;
                        LLSD::map_const_iterator iter = data.beginMap();
                        LLSD::map_const_iterator end = data.endMap();
                        for(; iter != end; ++iter)
                        {
                                ostr << pre << "<key>" << escapeString((*iter).first) << "</key>" << post;
                                format_count += format_impl((*iter).second, ostr, options, level + 1);
                        }
                        ostr << pre <<  "</map>" << post;
                }
                break;

        case LLSD::TypeArray:
                if(0 == data.size())
                {
                        ostr << pre << "<array />" << post;
                }
                else
                {
                        ostr << pre << "<array>" << post;
                        LLSD::array_const_iterator iter = data.beginArray();
                        LLSD::array_const_iterator end = data.endArray();
                        for(; iter != end; ++iter)
                        {
                                format_count += format_impl(*iter, ostr, options, level + 1);
                        }
                        ostr << pre << "</array>" << post;
                }
                break;

        case LLSD::TypeUndefined:
                ostr << pre << "<undef />" << post;
                break;

        case LLSD::TypeBoolean:
                ostr << pre << "<boolean>";
                if(mBoolAlpha ||
#if( LL_WINDOWS || __GNUC__ > 2)
                   (ostr.flags() & std::ios::boolalpha)
#else
                   (ostr.flags() & 0x0100)
#endif
                        )
                {
                        ostr << (data.asBoolean() ? "true" : "false");
                }
                else
                {
                        ostr << (data.asBoolean() ? 1 : 0);
                }
                ostr << "</boolean>" << post;
                break;

        case LLSD::TypeInteger:
                ostr << pre << "<integer>" << data.asInteger() << "</integer>" << post;
                break;

        case LLSD::TypeReal:
                ostr << pre << "<real>";
                if(mRealFormat.empty())
                {
                        ostr << data.asReal();
                }
                else
                {
                        formatReal(data.asReal(), ostr);
                }
                ostr << "</real>" << post;
                break;

        case LLSD::TypeUUID:
                if(data.asUUID().isNull()) ostr << pre << "<uuid />" << post;
                else ostr << pre << "<uuid>" << data.asUUID() << "</uuid>" << post;
                break;

        case LLSD::TypeString:
                if(data.asString().empty()) ostr << pre << "<string />" << post;
                else ostr << pre << "<string>" << escapeString(data.asString()) <<"</string>" << post;
                break;

        case LLSD::TypeDate:
                ostr << pre << "<date>" << data.asDate() << "</date>" << post;
                break;

        case LLSD::TypeURI:
                ostr << pre << "<uri>" << escapeString(data.asString()) << "</uri>" << post;
                break;

        case LLSD::TypeBinary:
        {
                LLSD::Binary buffer = data.asBinary();
                if(buffer.empty())
                {
                        ostr << pre << "<binary />" << post;
                }
                else
                {
                        // *FIX: memory inefficient.
                        // *TODO: convert to use LLBase64
                        ostr << pre << "<binary encoding=\"base64\">";
                        int b64_buffer_length = apr_base64_encode_len(buffer.size());
                        char* b64_buffer = new char[b64_buffer_length];
                        b64_buffer_length = apr_base64_encode_binary(
                                b64_buffer,
                                &buffer[0],
                                buffer.size());
                        ostr.write(b64_buffer, b64_buffer_length - 1);
                        delete[] b64_buffer;
                        ostr << "</binary>" << post;
                }
                break;
        }
        default:
                // *NOTE: This should never happen.
                ostr << pre << "<undef />" << post;
                break;
        }
        return format_count;
}

// static
std::string LLSDXMLFormatter::escapeString(const std::string& in)
{
        std::ostringstream out;
        std::string::const_iterator it = in.begin();
        std::string::const_iterator end = in.end();
        for(; it != end; ++it)
        {
                switch((*it))
                {
                case '<':
                        out << "&lt;";
                        break;
                case '>':
                        out << "&gt;";
                        break;
                case '&':
                        out << "&amp;";
                        break;
                case '\'':
                        out << "&apos;";
                        break;
                case '"':
                        out << "&quot;";
                        break;
                default:
                        out << (*it);
                        break;
                }
        }
        return out.str();
}



class LLSDXMLParser::Impl
{
public:
        Impl();
        ~Impl();
        
        S32 parse(std::istream& input, LLSD& data);

        void parsePart(const char *buf, int len);
        
private:
        void reset();
        
        void startElementHandler(const XML_Char* name, const XML_Char** attributes);
        void endElementHandler(const XML_Char* name);
        void characterDataHandler(const XML_Char* data, int length);
        
        static void sStartElementHandler(
                void* userData, const XML_Char* name, const XML_Char** attributes);
        static void sEndElementHandler(
                void* userData, const XML_Char* name);
        static void sCharacterDataHandler(
                void* userData, const XML_Char* data, int length);

        void startSkipping();
        
        enum Element {
                ELEMENT_LLSD,
                ELEMENT_UNDEF,
                ELEMENT_BOOL,
                ELEMENT_INTEGER,
                ELEMENT_REAL,
                ELEMENT_STRING,
                ELEMENT_UUID,
                ELEMENT_DATE,
                ELEMENT_URI,
                ELEMENT_BINARY,
                ELEMENT_MAP,
                ELEMENT_ARRAY,
                ELEMENT_KEY,
                ELEMENT_UNKNOWN
        };
        static Element readElement(const XML_Char* name);
        
        static const XML_Char* findAttribute(const XML_Char* name, const XML_Char** pairs);
        

        XML_Parser      mParser;

        LLSD mResult;
        S32 mParseCount;
        
        bool mInLLSDElement;
        bool mGracefullStop;
        
        typedef std::deque<LLSD*> LLSDRefStack;
        LLSDRefStack mStack;
        
        int mDepth;
        bool mSkipping;
        int mSkipThrough;
        
        std::string mCurrentKey;
        std::ostringstream mCurrentContent;

        bool mPreStaged;
};


LLSDXMLParser::Impl::Impl()
{
        mParser = XML_ParserCreate(NULL);
        mPreStaged = false;
        reset();
}

LLSDXMLParser::Impl::~Impl()
{
        XML_ParserFree(mParser);
}

bool is_eol(char c)
{
        return (c == '\n' || c == '\r');
}

void clear_eol(std::istream& input)
{
        char c = input.peek();
        while (input.good() && is_eol(c))
        {
                input.get(c);
                c = input.peek();
        }
}

static unsigned get_till_eol(std::istream& input, char *buf, unsigned bufsize)
{
        unsigned count = 0;
        while (count < bufsize && input.good())
        {
                input.get(buf[count]);
                count++;
                if (is_eol(buf[count - 1]))
                        break;
        }
        return count;
}

S32 LLSDXMLParser::Impl::parse(std::istream& input, LLSD& data)
{
        reset();
        XML_Status status;
        
        static const int BUFFER_SIZE = 1024;
        void* buffer = NULL;    
        int count = 0;
        while (input.good() && !input.eof())
        {
                buffer = XML_GetBuffer(mParser, BUFFER_SIZE);

                /*
                 * If we happened to end our last buffer right at the end of the llsd, but the
                 * stream is still going we will get a null buffer here.  Check for mGracefullStop.
                 */
                if (!buffer)
                {
                        break;
                }
                count = get_till_eol(input, (char *)buffer, BUFFER_SIZE);
                if (!count)
                {
                        break;
                }
                status = XML_ParseBuffer(mParser, count, false);

                if (status == XML_STATUS_ERROR)
                {
                        break;
                }
        }
        
        // *FIX.: This code is buggy - if the stream was empty or not
        // good, there is not buffer to parse, both the call to
        // XML_ParseBuffer and the buffer manipulations are illegal
        // futhermore, it isn't clear that the expat buffer semantics are
        // preserved

        status = XML_ParseBuffer(mParser, 0, true);
        if (status == XML_STATUS_ERROR && !mGracefullStop)
        {
                if (buffer)
                {
                        ((char*) buffer)[count ? count - 1 : 0] = '\0';
                }
                llinfos << "LLSDXMLParser::Impl::parse: XML_STATUS_ERROR parsing:" << (char*) buffer << llendl;
                data = LLSD();
                return LLSDParser::PARSE_FAILURE;
        }

        clear_eol(input);
        data = mResult;
        return mParseCount;
}

void LLSDXMLParser::Impl::reset()
{
        if (mPreStaged)
        {
                mPreStaged = false;
                return;
        }

        mResult.clear();
        mParseCount = 0;

        mInLLSDElement = false;
        mDepth = 0;

        mGracefullStop = false;

        mStack.clear();
        
        mSkipping = false;
        
#if( LL_WINDOWS || __GNUC__ > 2)
        mCurrentKey.clear();
#else
        mCurrentKey = std::string();
#endif

        
        XML_ParserReset(mParser, "utf-8");
        XML_SetUserData(mParser, this);
        XML_SetElementHandler(mParser, sStartElementHandler, sEndElementHandler);
        XML_SetCharacterDataHandler(mParser, sCharacterDataHandler);
}


void LLSDXMLParser::Impl::startSkipping()
{
        mSkipping = true;
        mSkipThrough = mDepth;
}

const XML_Char*
LLSDXMLParser::Impl::findAttribute(const XML_Char* name, const XML_Char** pairs)
{
        while (NULL != pairs && NULL != *pairs)
        {
                if(0 == strcmp(name, *pairs))
                {
                        return *(pairs + 1);
                }
                pairs += 2;
        }
        return NULL;
}

void LLSDXMLParser::Impl::parsePart(const char* buf, int len)
{
        void * buffer = XML_GetBuffer(mParser, len);
        if (buffer != NULL && buf != NULL)
        {
                memcpy(buffer, buf, len);
        }
        XML_ParseBuffer(mParser, len, false);

        mPreStaged = true;
}

void LLSDXMLParser::Impl::startElementHandler(const XML_Char* name, const XML_Char** attributes)
{
        ++mDepth;
        if (mSkipping)
        {
                return;
        }
        
        Element element = readElement(name);
        mCurrentContent.str("");

        switch (element)
        {
                case ELEMENT_LLSD:
                        if (mInLLSDElement) { return startSkipping(); }
                        mInLLSDElement = true;
                        return;
        
                case ELEMENT_KEY:
                        if (mStack.empty()  ||  !(mStack.back()->isMap()))
                        {
                                return startSkipping();
                        }
                        return;

                case ELEMENT_BINARY:
                {
                        const XML_Char* encoding = findAttribute("encoding", attributes);
                        if(encoding && strcmp("base64", encoding) != 0) { return startSkipping(); }
                        break;
                }
                
                default:
                        // all rest are values, fall through
                        ;
        }
        

        if (!mInLLSDElement) { return startSkipping(); }
        
        if (mStack.empty())
        {
                mStack.push_back(&mResult);
        }
        else if (mStack.back()->isMap())
        {
                if (mCurrentKey.empty()) { return startSkipping(); }
                
                LLSD& map = *mStack.back();
                LLSD& newElement = map[mCurrentKey];
                mStack.push_back(&newElement);          

#if( LL_WINDOWS || __GNUC__ > 2)
                mCurrentKey.clear();
#else
                mCurrentKey = std::string();
#endif
        }
        else if (mStack.back()->isArray())
        {
                LLSD& array = *mStack.back();
                array.append(LLSD());
                LLSD& newElement = array[array.size()-1];
                mStack.push_back(&newElement);
        }
        else {
                // improperly nested value in a non-structure
                return startSkipping();
        }

        ++mParseCount;
        switch (element)
        {
                case ELEMENT_MAP:
                        *mStack.back() = LLSD::emptyMap();
                        break;
                
                case ELEMENT_ARRAY:
                        *mStack.back() = LLSD::emptyArray();
                        break;
                        
                default:
                        // all the other values will be set in the end element handler
                        ;
        }
}

void LLSDXMLParser::Impl::endElementHandler(const XML_Char* name)
{
        --mDepth;
        if (mSkipping)
        {
                if (mDepth < mSkipThrough)
                {
                        mSkipping = false;
                }
                return;
        }
        
        Element element = readElement(name);
        
        switch (element)
        {
                case ELEMENT_LLSD:
                        if (mInLLSDElement)
                        {
                                mInLLSDElement = false;
                                mGracefullStop = true;
                                XML_StopParser(mParser, false);
                        }
                        return;
        
                case ELEMENT_KEY:
                        mCurrentKey = mCurrentContent.str();
                        return;
                        
                default:
                        // all rest are values, fall through
                        ;
        }
        
        if (!mInLLSDElement) { return; }

        LLSD& value = *mStack.back();
        mStack.pop_back();
        
        std::string content = mCurrentContent.str();
        mCurrentContent.str("");

        switch (element)
        {
                case ELEMENT_UNDEF:
                        value.clear();
                        break;
                
                case ELEMENT_BOOL:
                        value = content == "true" || content == "1";
                        break;
                
                case ELEMENT_INTEGER:
                        value = LLSD(content).asInteger();
                        break;
                
                case ELEMENT_REAL:
                        value = LLSD(content).asReal();
                        break;
                
                case ELEMENT_STRING:
                        value = content;
                        break;
                
                case ELEMENT_UUID:
                        value = LLSD(content).asUUID();
                        break;
                
                case ELEMENT_DATE:
                        value = LLSD(content).asDate();
                        break;
                
                case ELEMENT_URI:
                        value = LLSD(content).asURI();
                        break;
                
                case ELEMENT_BINARY:
                {
                        S32 len = apr_base64_decode_len(content.c_str());
                        std::vector<U8> data;
                        data.resize(len);
                        len = apr_base64_decode_binary(&data[0], content.c_str());
                        data.resize(len);
                        value = data;
                        break;
                }
                
                case ELEMENT_UNKNOWN:
                        value.clear();
                        break;
                        
                default:
                        // other values, map and array, have already been set
                        break;
        }
}

void LLSDXMLParser::Impl::characterDataHandler(const XML_Char* data, int length)
{
        mCurrentContent.write(data, length);
}


void LLSDXMLParser::Impl::sStartElementHandler(
        void* userData, const XML_Char* name, const XML_Char** attributes)
{
        ((LLSDXMLParser::Impl*)userData)->startElementHandler(name, attributes);
}

void LLSDXMLParser::Impl::sEndElementHandler(
        void* userData, const XML_Char* name)
{
        ((LLSDXMLParser::Impl*)userData)->endElementHandler(name);
}

void LLSDXMLParser::Impl::sCharacterDataHandler(
        void* userData, const XML_Char* data, int length)
{
        ((LLSDXMLParser::Impl*)userData)->characterDataHandler(data, length);
}


LLSDXMLParser::Impl::Element LLSDXMLParser::Impl::readElement(const XML_Char* name)
{
        if (strcmp(name, "llsd") == 0) { return ELEMENT_LLSD; }
        if (strcmp(name, "undef") == 0) { return ELEMENT_UNDEF; }
        if (strcmp(name, "boolean") == 0) { return ELEMENT_BOOL; }
        if (strcmp(name, "integer") == 0) { return ELEMENT_INTEGER; }
        if (strcmp(name, "real") == 0) { return ELEMENT_REAL; }
        if (strcmp(name, "string") == 0) { return ELEMENT_STRING; }
        if (strcmp(name, "uuid") == 0) { return ELEMENT_UUID; }
        if (strcmp(name, "date") == 0) { return ELEMENT_DATE; }
        if (strcmp(name, "uri") == 0) { return ELEMENT_URI; }
        if (strcmp(name, "binary") == 0) { return ELEMENT_BINARY; }
        if (strcmp(name, "map") == 0) { return ELEMENT_MAP; }
        if (strcmp(name, "array") == 0) { return ELEMENT_ARRAY; }
        if (strcmp(name, "key") == 0) { return ELEMENT_KEY; }
        
        return ELEMENT_UNKNOWN;
}





LLSDXMLParser::LLSDXMLParser() : impl(* new Impl)
{
}

LLSDXMLParser::~LLSDXMLParser()
{
        delete &impl;
}

void LLSDXMLParser::parsePart(const char *buf, int len)
{
        impl.parsePart(buf, len);
}

// virtual
S32 LLSDXMLParser::doParse(std::istream& input, LLSD& data) const
{
        return impl.parse(input, data); 
}

---