aria2/src/XML2SAXMetalinkProcessor.cc

/* <!-- copyright */
/*
 * aria2 - The high speed download utility
 *
 * Copyright (C) 2006 Tatsuhiro Tsujikawa
 *
 * 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 2 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * In addition, as a special exception, the copyright holders give
 * permission to link the code of portions of this program with the
 * OpenSSL library under certain conditions as described in each
 * individual source file, and distribute linked combinations
 * including the two.
 * You must obey the GNU General Public License in all respects
 * for all of the code used other than OpenSSL.  If you modify
 * file(s) with this exception, you may extend this exception to your
 * version of the file(s), but you are not obligated to do so.  If you
 * do not wish to do so, delete this exception statement from your
 * version.  If you delete this exception statement from all source
 * files in the program, then also delete it here.
 */
/* copyright --> */
#include "XML2SAXMetalinkProcessor.h"
#include "BinaryStream.h"
#include "MetalinkParserStateMachine.h"
#include "Metalinker.h"
#include "MetalinkEntry.h"
#include "util.h"
#include "message.h"
#include "DlAbortEx.h"

namespace aria2 {

class SessionData {
public:
  SharedHandle<MetalinkParserStateMachine> _stm;

  std::deque<std::string> _charactersStack;

  SessionData(const SharedHandle<MetalinkParserStateMachine>& stm):_stm(stm) {}
};

static void mlStartElement(void* userData, const xmlChar* name, const xmlChar** attrs)
{
  SessionData* sd = reinterpret_cast<SessionData*>(userData);
  std::map<std::string, std::string> attrmap;
  if(attrs) {
    const xmlChar** p = attrs;
    while(*p != 0) {
      std::string name = reinterpret_cast<const char*>(*p);
      ++p;
      if(*p == 0) {
        break;
      }
      std::string value = util::trim(reinterpret_cast<const char*>(*p));
      ++p;
      attrmap[name] = value;
    }
  }
  sd->_stm->beginElement(reinterpret_cast<const char*>(name), attrmap);
  if(sd->_stm->needsCharactersBuffering()) {
    sd->_charactersStack.push_front(std::string());
  }
}

static void mlEndElement(void* userData, const xmlChar* name)
{
  SessionData* sd = reinterpret_cast<SessionData*>(userData);
  std::string characters;
  if(sd->_stm->needsCharactersBuffering()) {
    characters = util::trim(sd->_charactersStack.front());
    sd->_charactersStack.pop_front();
  }
  sd->_stm->endElement(reinterpret_cast<const char*>(name), characters);
}

static void mlCharacters(void* userData, const xmlChar* ch, int len)
{
  SessionData* sd = reinterpret_cast<SessionData*>(userData);
  if(sd->_stm->needsCharactersBuffering()) {
    sd->_charactersStack.front() += std::string(&ch[0], &ch[len]);
  }
}

static xmlSAXHandler mySAXHandler =
  {
    0, // internalSubsetSAXFunc
    0, // isStandaloneSAXFunc
    0, // hasInternalSubsetSAXFunc
    0, // hasExternalSubsetSAXFunc
    0, // resolveEntitySAXFunc
    0, // getEntitySAXFunc
    0, // entityDeclSAXFunc
    0, // notationDeclSAXFunc
    0, // attributeDeclSAXFunc
    0, // elementDeclSAXFunc
    0, //   unparsedEntityDeclSAXFunc
    0, //   setDocumentLocatorSAXFunc
    0, //   startDocumentSAXFunc
    0, //   endDocumentSAXFunc
    &mlStartElement, //   startElementSAXFunc
    &mlEndElement, //   endElementSAXFunc
    0, //   referenceSAXFunc
    &mlCharacters, //   charactersSAXFunc
    0, //   ignorableWhitespaceSAXFunc
    0, //   processingInstructionSAXFunc
    0, //   commentSAXFunc
    0, //   warningSAXFunc
    0, //   errorSAXFunc
    0, //   fatalErrorSAXFunc
    0, //   getParameterEntitySAXFunc
    0, //   cdataBlockSAXFunc
    0, //   externalSubsetSAXFunc
    0, //   unsigned int        initialized
    0, //   void *      _private
    0, //   startElementNsSAX2Func
    0, //   endElementNsSAX2Func
    0, //   xmlStructuredErrorFunc
  };

SharedHandle<Metalinker>
MetalinkProcessor::parseFile(const std::string& filename)
{
  _stm.reset(new MetalinkParserStateMachine());
  SharedHandle<SessionData> sessionData(new SessionData(_stm));
  int retval = xmlSAXUserParseFile(&mySAXHandler, sessionData.get(),
                                   filename.c_str());
  if(retval != 0) {
    throw DL_ABORT_EX(MSG_CANNOT_PARSE_METALINK);
  }
  return _stm->getResult();
}
         
SharedHandle<Metalinker>
MetalinkProcessor::parseFromBinaryStream(const SharedHandle<BinaryStream>& binaryStream)
{
  _stm.reset(new MetalinkParserStateMachine());
  size_t bufSize = 4096;
  unsigned char buf[bufSize];

  ssize_t res = binaryStream->readData(buf, 4, 0);
  if(res != 4) {
    throw DL_ABORT_EX("Too small data for parsing XML.");
  }

  SharedHandle<SessionData> sessionData(new SessionData(_stm));
  xmlParserCtxtPtr ctx = xmlCreatePushParserCtxt
    (&mySAXHandler, sessionData.get(),
     reinterpret_cast<const char*>(buf), res, 0);
  try {
    off_t readOffset = res;
    while(1) {
      ssize_t res = binaryStream->readData(buf, bufSize, readOffset);
      if(res == 0) {
        break;
      }
      if(xmlParseChunk(ctx, reinterpret_cast<const char*>(buf), res, 0) != 0) {
        throw DL_ABORT_EX(MSG_CANNOT_PARSE_METALINK);
      }
      readOffset += res;
    }
    xmlParseChunk(ctx, reinterpret_cast<const char*>(buf), 0, 1);
  } catch(Exception& e) {
    xmlFreeParserCtxt(ctx);
    throw;
  }
  xmlFreeParserCtxt(ctx);

  if(!_stm->finished()) {
    throw DL_ABORT_EX(MSG_CANNOT_PARSE_METALINK);
  }
  return _stm->getResult();
}

} // namespace aria2