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/*
Ousía
Copyright (C) 2014, 2015 Benjamin Paaßen, Andreas Stöckel
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <iostream>
#include <expat.h>
#include "XmlParser.hpp"
namespace ousia {
namespace parser {
namespace xml {
/**
* Wrapper class around the XML_Parser pointer which safely frees it whenever
* the scope is left (e.g. because an exception was thrown).
*/
class ScopedExpatXmlParser {
private:
/**
* Internal pointer to the XML_Parser instance.
*/
XML_Parser parser;
public:
/**
* Constructor of the ScopedExpatXmlParser class. Calls XML_ParserCreateNS
* from the expat library. Throws a parser exception if the XML parser
* cannot be initialized.
*
* @param encoding is the protocol-defined encoding passed to expat (or
* nullptr if expat should determine the encoding by itself).
*/
ScopedExpatXmlParser(const XML_Char *encoding)
: parser(nullptr)
{
parser = XML_ParserCreate(encoding);
if (!parser) {
throw ParserException{
"Internal error: Could not create expat XML parser!"};
}
}
/**
* Destuctor of the ScopedExpatXmlParser, frees the XML parser instance.
*/
~ScopedExpatXmlParser()
{
if (parser) {
XML_ParserFree(parser);
parser = nullptr;
}
}
/**
* Returns the XML_Parser pointer.
*/
XML_Parser operator&() { return parser; }
};
static void xmlStartElementHandler(void *userData, const XML_Char *name,
const XML_Char **attrs)
{
std::cout << "start tag: " << name << std::endl;
const XML_Char **attr = attrs;
while (*attr) {
std::cout << "\t" << *attr;
attr++;
std::cout << " -> " << *attr << std::endl;
attr++;
}
}
static void xmlEndElementHandler(void *userData, const XML_Char *name) {
std::cout << "end tag: " << name << std::endl;
}
static void xmlCharacterDataHandler(void *userData, const XML_Char *s, int len) {
std::cout << "\tdata: " << std::string(s, len) << std::endl;
}
std::set<std::string> XmlParser::mimetypes()
{
return std::set<std::string>{{"text/vnd.ousia.oxm", "text/vnd.ousia.oxd"}};
}
Rooted<Node> XmlParser::parse(std::istream &is, ParserContext &ctx)
{
// Create the parser object
ScopedExpatXmlParser p{"UTF-8"};
XML_SetUserData(&p, &ctx);
// Set the callback functions
XML_SetStartElementHandler(&p, xmlStartElementHandler);
XML_SetEndElementHandler(&p, xmlEndElementHandler);
XML_SetCharacterDataHandler(&p, xmlCharacterDataHandler);
// Feed data into expat while there is data to process
const std::streamsize BUFFER_SIZE = 4096; // TODO: Move to own header?
while (true) {
// Fetch a buffer from expat for the input data
char *buf = static_cast<char *>(XML_GetBuffer(&p, BUFFER_SIZE));
if (!buf) {
throw ParserException{"Internal error: XML parser out of memory!"};
}
// Read the input data from the stream
const std::streamsize bytesRead = is.read(buf, BUFFER_SIZE).gcount();
// Parse the data and handle any XML error
if (!XML_ParseBuffer(&p, bytesRead, bytesRead == 0)) {
const int line = XML_GetCurrentLineNumber(&p);
const int column = XML_GetCurrentColumnNumber(&p);
const XML_Error code = XML_GetErrorCode(&p);
const std::string msg = std::string{XML_ErrorString(code)};
throw ParserException{"XML Syntax Error: " + msg, line, column,
false};
}
// Abort once there are no more bytes in the stream
if (bytesRead == 0) {
break;
}
}
return nullptr;
}
}
}
}
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