xml_sax_parser.cc

// Copyright 2009, Squish Tech, LLC.

#include "nan.h"
#include <node.h>

#include "parserInternals.h"

#include "libxmljs.h"
#include "xml_sax_parser.h"

libxmljs::XmlSaxParser *LXJS_GET_PARSER_FROM_CONTEXT(void *context) {
    _xmlParserCtxt *the_context = static_cast<_xmlParserCtxt *>(context);
    return static_cast<libxmljs::XmlSaxParser *>(the_context->_private);
}

#define EMIT_SYMBOL_STRING "emit"

namespace {
using namespace v8; // node 0.4.7 fails to use v8:: in NODE_PSYMBOL
Nan::Persistent<v8::String> emit_symbol;
} // namespace

namespace libxmljs {

XmlSaxParser::XmlSaxParser() : context_(NULL) {
    xmlSAXHandler tmp = {
        0, // internalSubset;
        0, // isStandalone;
        0, // hasInternalSubset;
        0, // hasExternalSubset;
        0, // resolveEntity;
        0, // getEntity;
        0, // entityDecl;
        0, // notationDecl;
        0, // attributeDecl;
        0, // elementDecl;
        0, // unparsedEntityDecl;
        0, // setDocumentLocator;
        XmlSaxParser::start_document,
        XmlSaxParser::end_document, // endDocument;
        0,                          // startElement;
        0,                          // endElement;
        0,                          // reference;
        XmlSaxParser::characters,   // characters;
        0,                          // ignorableWhitespace;
        0,                          // processingInstruction;
        XmlSaxParser::comment,      // comment;
        XmlSaxParser::warning,      // warning;
        XmlSaxParser::error,        // error;
        0, // fatalError; /* unused error() get all the errors */
        0, // getParameterEntity;
        XmlSaxParser::cdata_block,      // cdataBlock;
        0,                              // externalSubset;
        XML_SAX2_MAGIC,                 /* force SAX2 */
        this,                           /* _private */
        XmlSaxParser::start_element_ns, // startElementNs;
        XmlSaxParser::end_element_ns,   // endElementNs;
        0 // SaxParserCallback::structured_error // serror
    };

    sax_handler_ = tmp;
}

XmlSaxParser::~XmlSaxParser() { this->releaseContext(); }

void XmlSaxParser::initializeContext() {
    assert(context_);
    context_->validate = 0;
    context_->_private = this;
}

void XmlSaxParser::releaseContext() {
    if (context_) {
        context_->_private = 0;
        if (context_->myDoc != NULL) {
            xmlFreeDoc(context_->myDoc);
            context_->myDoc = NULL;
        }

        xmlFreeParserCtxt(context_);
        context_ = 0;
    }
}

NAN_METHOD(XmlSaxParser::NewParser) {
    Nan::HandleScope scope;
    XmlSaxParser *parser = new XmlSaxParser();
    parser->Wrap(info.Holder());

    return info.GetReturnValue().Set(info.Holder());
}

NAN_METHOD(XmlSaxParser::NewPushParser) {
    Nan::HandleScope scope;
    XmlSaxParser *parser = new XmlSaxParser();
    parser->initialize_push_parser();
    parser->Wrap(info.Holder());

    return info.GetReturnValue().Set(info.Holder());
}

void XmlSaxParser::Callback(const char *what, int argc,
                            v8::Local<v8::Value> argv[]) {
    Nan::HandleScope scope;

    // new arguments array with first argument being the event name
    v8::Local<v8::Value> *args = new v8::Local<v8::Value>[argc + 1];
    args[0] = Nan::New<v8::String>(what).ToLocalChecked();
    for (int i = 1; i <= argc; ++i) {
        args[i] = argv[i - 1];
    }

    // get the 'emit' function from ourselves
    v8::Local<v8::Value> emit_v =
        Nan::Get(this->handle(), Nan::New(emit_symbol)).ToLocalChecked();
    assert(emit_v->IsFunction());

    // trigger the event
    Nan::MakeCallback(this->handle(), v8::Local<v8::Function>::Cast(emit_v),
                      argc + 1, args);

    delete[] args;
}

NAN_METHOD(XmlSaxParser::Push) {
    Nan::HandleScope scope;
    LIBXMLJS_ARGUMENT_TYPE_CHECK(info[0], IsString,
                                 "Bad Argument: parseString requires a string");

    XmlSaxParser *parser = Nan::ObjectWrap::Unwrap<XmlSaxParser>(info.Holder());

    Nan::Utf8String parsable(Nan::To<v8::String>(info[0]).ToLocalChecked());

    bool terminate =
        info.Length() > 1
            ? Nan::To<v8::Boolean>(info[1]).ToLocalChecked()->Value()
            : false;

    parser->push(*parsable, parsable.length(), terminate);

    return info.GetReturnValue().Set(Nan::True());
}

void XmlSaxParser::initialize_push_parser() {
    context_ = xmlCreatePushParserCtxt(&sax_handler_, NULL, NULL, 0, "");
    context_->replaceEntities = 1;
    initializeContext();
}

void XmlSaxParser::push(const char *str, unsigned int size,
                        bool terminate = false) {
    auto prevCtx = xmlStructuredErrorContext;
    auto prevErr = xmlStructuredError;
    xmlSetStructuredErrorFunc(NULL, NULL);
    xmlParseChunk(context_, str, size, terminate);
    xmlSetStructuredErrorFunc(prevCtx, prevErr);
}

NAN_METHOD(XmlSaxParser::ParseString) {
    Nan::HandleScope scope;
    LIBXMLJS_ARGUMENT_TYPE_CHECK(info[0], IsString,
                                 "Bad Argument: parseString requires a string");

    XmlSaxParser *parser = Nan::ObjectWrap::Unwrap<XmlSaxParser>(info.Holder());

    Nan::Utf8String parsable(Nan::To<v8::String>(info[0]).ToLocalChecked());
    parser->parse_string(*parsable, parsable.length());

    // TODO(sprsquish): return based on the parser
    return info.GetReturnValue().Set(Nan::True());
}

void XmlSaxParser::parse_string(const char *str, unsigned int size) {
    auto prevCtx = xmlStructuredErrorContext;
    auto prevErr = xmlStructuredError;
    xmlSetStructuredErrorFunc(NULL, NULL);
    context_ = xmlCreateMemoryParserCtxt(str, size);
    initializeContext();
    context_->replaceEntities = 1;
    xmlSAXHandler *old_sax = context_->sax;
    context_->sax = &sax_handler_;
    xmlParseDocument(context_);
    context_->sax = old_sax;
    releaseContext();
    xmlSetStructuredErrorFunc(prevCtx, prevErr);
}

void XmlSaxParser::start_document(void *context) {
    libxmljs::XmlSaxParser *parser = LXJS_GET_PARSER_FROM_CONTEXT(context);
    parser->Callback("startDocument");
}

void XmlSaxParser::end_document(void *context) {
    libxmljs::XmlSaxParser *parser = LXJS_GET_PARSER_FROM_CONTEXT(context);
    parser->Callback("endDocument");
}

void XmlSaxParser::start_element_ns(void *context, const xmlChar *localname,
                                    const xmlChar *prefix, const xmlChar *uri,
                                    int nb_namespaces,
                                    const xmlChar **namespaces,
                                    int nb_attributes, int nb_defaulted,
                                    const xmlChar **attributes) {
    Nan::HandleScope scope;
    libxmljs::XmlSaxParser *parser = LXJS_GET_PARSER_FROM_CONTEXT(context);

    const int argc = 5;
    const xmlChar *nsPref, *nsUri, *attrLocal, *attrPref, *attrUri, *attrVal;
    int i, j;

    v8::Local<v8::Array> elem;

    // Initialize argv with localname, prefix, and uri
    v8::Local<v8::Value> argv[argc] = {
        Nan::New<v8::String>((const char *)localname).ToLocalChecked()};

    // Build attributes list
    // Each attribute is an array of [localname, prefix, URI, value, end]
    v8::Local<v8::Array> attrList = Nan::New<v8::Array>(nb_attributes);
    if (attributes) {
        for (i = 0, j = 0; j < nb_attributes; i += 5, j++) {
            attrLocal = attributes[i + 0];
            attrPref = attributes[i + 1];
            attrUri = attributes[i + 2];
            attrVal = attributes[i + 3];

            elem = Nan::New<v8::Array>(4);

            Nan::Set(elem, Nan::New<v8::Integer>(0),
                     Nan::New<v8::String>((const char *)attrLocal,
                                          xmlStrlen(attrLocal))
                         .ToLocalChecked());

            Nan::Set(elem, Nan::New<v8::Integer>(1),
                     Nan::New<v8::String>((const char *)attrPref,
                                          xmlStrlen(attrPref))
                         .ToLocalChecked());

            Nan::Set(
                elem, Nan::New<v8::Integer>(2),
                Nan::New<v8::String>((const char *)attrUri, xmlStrlen(attrUri))
                    .ToLocalChecked());

            Nan::Set(elem, Nan::New<v8::Integer>(3),
                     Nan::New<v8::String>((const char *)attrVal,
                                          attributes[i + 4] - attrVal)
                         .ToLocalChecked());

            Nan::Set(attrList, Nan::New<v8::Integer>(j), elem);
        }
    }
    argv[1] = attrList;

    if (prefix) {
        argv[2] = Nan::New<v8::String>((const char *)prefix).ToLocalChecked();
    } else {
        argv[2] = Nan::Null();
    }

    if (uri) {
        argv[3] = Nan::New<v8::String>((const char *)uri).ToLocalChecked();
    } else {
        argv[3] = Nan::Null();
    }

    // Build namespace array of arrays [[prefix, ns], [prefix, ns]]
    v8::Local<v8::Array> nsList = Nan::New<v8::Array>(nb_namespaces);
    if (namespaces) {
        for (i = 0, j = 0; j < nb_namespaces; j++) {
            nsPref = namespaces[i++];
            nsUri = namespaces[i++];

            elem = Nan::New<v8::Array>(2);
            if (xmlStrlen(nsPref) == 0) {
                Nan::Set(elem, Nan::New<v8::Integer>(0), Nan::Null());
            } else {
                Nan::Set(elem, Nan::New<v8::Integer>(0),
                         Nan::New<v8::String>((const char *)nsPref,
                                              xmlStrlen(nsPref))
                             .ToLocalChecked());
            }

            Nan::Set(elem, Nan::New<v8::Integer>(1),
                     Nan::New<v8::String>((const char *)nsUri, xmlStrlen(nsUri))
                         .ToLocalChecked());

            Nan::Set(nsList, Nan::New<v8::Integer>(j), elem);
        }
    }
    argv[4] = nsList;

    parser->Callback("startElementNS", argc, argv);
}

void XmlSaxParser::end_element_ns(void *context, const xmlChar *localname,
                                  const xmlChar *prefix, const xmlChar *uri) {
    Nan::HandleScope scope;
    libxmljs::XmlSaxParser *parser = LXJS_GET_PARSER_FROM_CONTEXT(context);

    v8::Local<v8::Value> argv[3];
    argv[0] = Nan::New<v8::String>((const char *)localname).ToLocalChecked();

    if (prefix) {
        argv[1] = Nan::New<v8::String>((const char *)prefix).ToLocalChecked();
    } else {
        argv[1] = Nan::Null();
    }

    if (uri) {
        argv[2] = Nan::New<v8::String>((const char *)uri).ToLocalChecked();
    } else {
        argv[2] = Nan::Null();
    }

    parser->Callback("endElementNS", 3, argv);
}

void XmlSaxParser::characters(void *context, const xmlChar *ch, int len) {
    Nan::HandleScope scope;
    libxmljs::XmlSaxParser *parser = LXJS_GET_PARSER_FROM_CONTEXT(context);

    v8::Local<v8::Value> argv[1] = {
        Nan::New<v8::String>((const char *)ch, len).ToLocalChecked()};
    parser->Callback("characters", 1, argv);
}

void XmlSaxParser::comment(void *context, const xmlChar *value) {
    Nan::HandleScope scope;
    libxmljs::XmlSaxParser *parser = LXJS_GET_PARSER_FROM_CONTEXT(context);
    v8::Local<v8::Value> argv[1] = {
        Nan::New<v8::String>((const char *)value).ToLocalChecked()};
    parser->Callback("comment", 1, argv);
}

void XmlSaxParser::cdata_block(void *context, const xmlChar *value, int len) {
    Nan::HandleScope scope;
    libxmljs::XmlSaxParser *parser = LXJS_GET_PARSER_FROM_CONTEXT(context);
    v8::Local<v8::Value> argv[1] = {
        Nan::New<v8::String>((const char *)value, len).ToLocalChecked()};
    parser->Callback("cdata", 1, argv);
}

#ifdef WIN32
// https://github.com/json-c/json-c/blob/master/printbuf.c
// Copyright (c) 2004, 2005 Metaparadigm Pte Ltd
static int vasprintf(char **buf, const char *fmt, va_list ap) {
    int chars;
    char *b;

    if (!buf) {
        return -1;
    }

    chars = _vscprintf(fmt, ap) + 1;

    b = (char *)malloc(sizeof(char) * chars);
    if (!b) {
        return -1;
    }

    if ((chars = vsprintf(b, fmt, ap)) < 0) {
        free(b);
    } else {
        *buf = b;
    }

    return chars;
}
#endif /* WIN32 */

void XmlSaxParser::warning(void *context, const char *msg, ...) {
    Nan::HandleScope scope;
    libxmljs::XmlSaxParser *parser = LXJS_GET_PARSER_FROM_CONTEXT(context);

    char *message;

    va_list args;
    va_start(args, msg);
    if (vasprintf(&message, msg, args) >= 0) {
        v8::Local<v8::Value> argv[1] = {
            Nan::New<v8::String>((const char *)message).ToLocalChecked()};
        parser->Callback("warning", 1, argv);
    }

    va_end(args);
    free(message);
}

void XmlSaxParser::error(void *context, const char *msg, ...) {
    Nan::HandleScope scope;
    libxmljs::XmlSaxParser *parser = LXJS_GET_PARSER_FROM_CONTEXT(context);

    char *message;

    va_list args;
    va_start(args, msg);
    if (vasprintf(&message, msg, args) >= 0) {
        v8::Local<v8::Value> argv[1] = {
            Nan::New<v8::String>((const char *)message).ToLocalChecked()};
        parser->Callback("error", 1, argv);
    }

    va_end(args);
    free(message);
}

void XmlSaxParser::Initialize(v8::Local<v8::Object> target) {
    Nan::HandleScope scope;

    emit_symbol.Reset(
        Nan::New<v8::String>(EMIT_SYMBOL_STRING).ToLocalChecked());

    // SAX Parser
    v8::Local<v8::FunctionTemplate> parser_t =
        Nan::New<v8::FunctionTemplate>(NewParser);

    Nan::Persistent<v8::FunctionTemplate> sax_parser_template;
    sax_parser_template.Reset(parser_t);

    parser_t->InstanceTemplate()->SetInternalFieldCount(1);

    Nan::SetPrototypeMethod(parser_t, "parseString", XmlSaxParser::ParseString);

    Nan::Set(target, Nan::New<v8::String>("SaxParser").ToLocalChecked(),
             Nan::GetFunction(parser_t).ToLocalChecked());

    v8::Local<v8::FunctionTemplate> push_parser_t =
        Nan::New<v8::FunctionTemplate>(NewPushParser);

    // Push Parser
    Nan::Persistent<v8::FunctionTemplate> sax_push_parser_template;
    sax_push_parser_template.Reset(push_parser_t);

    push_parser_t->InstanceTemplate()->SetInternalFieldCount(1);

    Nan::SetPrototypeMethod(push_parser_t, "push", XmlSaxParser::Push);

    Nan::Set(target, Nan::New<v8::String>("SaxPushParser").ToLocalChecked(),
             Nan::GetFunction(push_parser_t).ToLocalChecked());
}
} // namespace libxmljs