CentralConfig.cc

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#include <config.h>

#include <fwk/CentralConfig.h>
#include <fwk/GITGlobalRevision.h>
#include <fwk/VModule.h>

#include <utl/ReaderErrorReporter.h>
#include <utl/ErrorLogger.h>
#include <utl/Reader.h>
#include <utl/XercesUtil.h>
#include <utl/StringCompare.h>

#include <fwk/RunController.h>

#include "CentralConfig/Md5Fingerprints.icc"  // fingerprint generated by configure
#include "CentralConfig/Md5Excludes.icc"  // list of files to ignore when checking fingerprints

#include <xercesc/dom/DOM.hpp>

#ifndef _GNU_SOURCE
#  define _GNU_SOURCE
#endif
#include <dlfcn.h>
#include <boost/filesystem.hpp>
#include <boost/process.hpp>

#include <fstream>

using namespace fwk;
using namespace std;
using namespace utl;
using namespace xercesc;
namespace bfs = boost::filesystem;


namespace fwk {

  CentralConfig* CentralConfig::fgInstance = nullptr;
  bool CentralConfig::fgIsInitialized = false;
  bool CentralConfig::fgValidate = true;


  string
  AsString(DOMNode& n)
  {
    switch (n.getNodeType()) {
    case DOMNode::TEXT_NODE:
      return utl::AsString(n.getNodeValue());
    case DOMNode::COMMENT_NODE:
      return "<!--" + utl::AsString(n.getNodeValue()) + "-->";
    default:
      return "!!!unhandled DOMNode type " + to_string(n.getNodeType()) + "!!!";
    }
  }


  inline
  string
  AsXML(const AttributeMap& attr)
  {
    ostringstream os;
    for (const auto& kv : attr)
      os << ' ' << kv.first << "=\"" << kv.second << '\"';
    return os.str();
  }


  const char*
  GetLibraryPath()
  {
    Dl_info dlInfo;
    return dladdr((void*)GetLibraryPath, &dlInfo) ? dlInfo.dli_fname : "";
  }

}


CentralConfig::CentralConfig()
{
  const char* const libPath = GetLibraryPath();
  if (libPath && libPath[0])
    fInstallPath = bfs::path(libPath).parent_path().parent_path().string();
}


CentralConfig::~CentralConfig()
{
  delete fBootstrapReader;

  for (const auto& c : fConfigMap)
    delete c.second.GetReader();

  fgIsInitialized = false;
}


CentralConfig*
CentralConfig::GetInstance(const string& name,
                           const bool fingerprintFatal,
                           const bool validate)
{
  fgValidate = validate;

  static CentralConfig cc;  // Mayer's singleton

  fgInstance = &cc;

  static string bootstrapFile;

  if (!fgIsInitialized) {

    cc.ReadConfig(name);
    cc.FillMd5Excludes();
    cc.CheckFingerprints(fingerprintFatal);
    fgIsInitialized = true;
    bootstrapFile = name;

  } else if (bootstrapFile != name) {

    INFO("You have requested the instance of CentralConfig "
         "specifying a bootstrap file. "
         "However, in a previous instantiation, you requested "
         "a different bootstrap file. This is not "
         "allowed. Not changing the configuraton.");

  }

  return fgInstance;
}


void
CentralConfig::Reset(const std::string& bootstrapFileName,
                     const bool fingerprintFatal,
                     const bool validate)
{
  const string b = fgInstance->GetBootstrapUri();
  fgInstance = nullptr;
  fgIsInitialized = false;
  if (bootstrapFileName.empty())
    CentralConfig::GetInstance(b, fingerprintFatal, validate);
  else
    CentralConfig::GetInstance(bootstrapFileName, fingerprintFatal, validate);
}


void
CentralConfig::ReadConfig(const string& bootstrapFile)
{
  if (fBootstrapReader)
    throw XMLParseException("CentralConfig should be initialized only once!");

  fBootstrapReader = new Reader(bootstrapFile, Reader::eSCHEMA);

  Branch topBranch = fBootstrapReader->GetTopBranch();

  Branch severityBranch = topBranch.GetChild("minSeverity");
  if (severityBranch) {
    ErrorLogger& logger = ErrorLogger::GetInstance();
    string severity;
    severityBranch.GetData(severity);
    if (severity == "debug")
      logger.SetMinSeverity(ErrorLogger::eDebug);
    else if (severity == "info")
      logger.SetMinSeverity(ErrorLogger::eInfo);
    else if (severity == "warning")
      logger.SetMinSeverity(ErrorLogger::eWarning);
    else if (severity == "error")
      logger.SetMinSeverity(ErrorLogger::eError);
    else if (severity == "fatal")
      logger.SetMinSeverity(ErrorLogger::eFatal);
  }

  // Loop over all children of the top Branch which are called
  // centralConfig.  configLinks appearing in later centralConfig
  // file will replace those in earlier ones
  //
  for (Branch ccB = topBranch.GetFirstChild(); ccB; ccB = ccB.GetNextSibling()) {
    const string& name = ccB.GetName();
    if (name == "centralConfig" || name == "defaultConfig")
      FillMap(ccB);
    else if (name == "parameterOverrides")
      ReplaceParameters(ccB);
  }
}


CentralConfig*
CentralConfig::GetInstance()
{
  if (!fgInstance)
    throw utl::IOFailureException(
      "The first time you call CentralConfig::GetInstance(...), "
      "you MUST pass the name of the bootstrap configuration file"
    );

  return fgInstance;
}


Branch
CentralConfig::GetTopBranch(const std::string& id)
{
  const Reader* const reader = GetReader(id);
  if (reader)
    return reader->GetTopBranch();
  else {
    ostringstream msg;
    msg << "Cannot find Configuration file for <configLink> with id=\""
        << id << '"';
    Branch b;
    b.SetWarning(msg.str());
    return b;
  }
}


const Reader*
CentralConfig::GetReader(const string& id)
{
  fUsedConfigs.emplace(id);

  const auto it = fConfigMap.find(id);

  if (it != fConfigMap.end()) {

    Reader* const reader = it->second.GetReader();
    if (reader)
      return reader;
    else {
      ostringstream msg;
      msg << "You requested a Reader for a file format "
             "which cannot be accessed by the Reader "
             "Configuration Id '"
          << it->second.fXLink << "' of type "
          << it->second.fFileType;
      INFO(msg);
    }

  } else {
    ostringstream msg;
    msg << "Cannot find requested Id: '" << id << '\'';
    DEBUGLOG(msg);
  }

  return nullptr;
}


string
CentralConfig::GetBootstrapUri()
{
  if (fBootstrapReader)
    return fBootstrapReader->GetUri();
  return "";
}


/*void
CentralConfig::SetTopBranch(const std::string& id, const utl::Branch& branch)
{
  ConfigLink configLink;
  configLink.fFileType = "XML";
  configLink.fReader = new Reader(branch.Clone());

  // Check for configLink override
  const auto previousConfigLink = fConfigMap.find(id);
  if (previousConfigLink != fConfigMap.end()) {
    delete previousConfigLink->second.fReader;
    previousConfigLink->second = configLink;
  } else {
    fConfigMap.insert(pair<string, ConfigLink>(id, configLink));
    GetTopBranch(id);
  }
}*/


void
CentralConfig::FillMap(const Branch& configBranch)
{
  typedef map<string, list<string>> OvConfig;

  if (!configBranch)
    return;

  // holds information about overridden config files for report generation
  OvConfig overriddenConfigs;

  for (Branch cB = configBranch.GetFirstChild(); cB; cB = cB.GetNextSibling()) {

    if (cB.GetName() == "configLink") {

      const AttributeMap attMap = cB.GetAttributes();

      string id;
      {
        const auto it = attMap.find("id");
        if (it != attMap.end())
          id = it->second;
        else {
          const auto it = attMap.find("ID");
          if (it != attMap.end())
            id = it->second;
          else
            AbortParse("<configLink> found without 'id' attribute.");
        }
      }

      ConfigLink configLink;
      {
        const auto it = attMap.find("type");
        if (it == attMap.end())
          AbortParse("<configLink> found without 'type' attribute.");
        configLink.fFileType = it->second;
      }
      {
        const auto it = attMap.find("xlink:href");
        if (it == attMap.end())
          AbortParse("<configLink> found without 'xlink:href' attribute.");
        configLink.fXLink = it->second;
      }

      // Set the reader
      if (StringEquivalent(configLink.fFileType, "XML")) {

        if (configLink.fXLink[0] == '#') {

          const string path = configLink.fXLink.substr(1);

          Branch branch = Find(path);
          if (branch) {
            branch = branch.GetFirstChild();
            const string mybranch = AsString(branch);
            try {
              configLink.fReader = new Reader(ReaderStringInput(mybranch));
            } catch (XMLParseException& ex) {
              AbortParse("Failure to parse from input string. " + ex.GetMessage());
            }
          }
        } else if (!fgValidate) {
          try {
            ostringstream msg;
            msg << "Explicit request to parse a file without validation."
                   "Filename = " << configLink.fXLink;
            WARNING(msg);
            configLink.fReader = new Reader(configLink.fXLink, Reader::eNONE);
          } catch (XMLParseException& ex) {
            AbortParse("Failure to parse with (validation switched off). " + ex.GetMessage());
          }
        } else {
          try {
            configLink.fReader = new Reader(configLink.fXLink, Reader::eSCHEMA);
          } catch (XMLParseException& ex) {
            AbortParse(ex.GetMessage());
          }
        }
      }

      // Check for configLink override
      const auto previousConfigLink = fConfigMap.find(id);

      if (previousConfigLink != fConfigMap.end()) {

        if (previousConfigLink->second.fXLink != configLink.fXLink) {
          // previously overridden
          auto& ov = overriddenConfigs[id];
          if (ov.empty())
            ov.push_back(previousConfigLink->second.fXLink);
          ov.push_back(configLink.fXLink);
        }

        delete previousConfigLink->second.fReader;
        fConfigMap.erase(previousConfigLink);

      }

      // Insert the config info into the configMap
      fConfigMap.emplace(id, configLink);

    }

  }

  // generate report about overridden configuration files
  if (!overriddenConfigs.empty()) {
    ostringstream msg;
    msg << "The following configuration files have been overridden. "
           "Files sorted from original to newest override:";
    for (const auto& c : overriddenConfigs) {
      const string& id = c.first;
      const list<string>& files = c.second;
      if (files.empty())
        continue;
      msg << "\n  * Id: '" << id << "', files:";
      const unsigned int n = files.size();
      unsigned int i = 0;
      for (const auto& f : files) {
        msg << "\n      ";
        if (!i)
          msg << "(original   )";
        else if (i == n-1)
          msg << "(replaced by)";
        else
          msg << "(        old)";
        msg << " '" << f << '\'';
        ++i;
      }
    }
    INFO(msg);
  }

  static bool checkedAlready = false;
  if (!checkedAlready) {
    checkedAlready = true;
    // check for duplicated top branches
    map<string, set<string>> dupBrCl;
    for (auto it = fConfigMap.begin(), end = fConfigMap.end(); it != end; ++it) {
      if (const Reader* const ri = it->second.GetReader()) {
        const string& topBranchName = ri->GetTopBranch().GetName();
        for (auto jt = next(it); jt != end; ++jt) {
          if (const Reader* const rj = jt->second.GetReader()) {
            if (topBranchName == rj->GetTopBranch().GetName()) {
              auto& d = dupBrCl[topBranchName];
              d.insert(it->first);
              d.insert(jt->first);
            }
          }
        }
      }
    }
    if (!dupBrCl.empty()) {
      ostringstream warn;
      for (const auto& d : dupBrCl) {
        warn << "The same top branch <" << d.first << "> has been "
                "encountered in the following <configLink>s with ids:";
        for (const auto& c : d.second)
          warn << ' ' << c;
      }
      WARNING(warn);
    }
  }
}


void
CentralConfig::ReplaceParameters(const Branch& b)
{
  for (Branch cB = b.GetFirstChild(); cB; cB = cB.GetNextSibling()) {

    // Look up the reader for requested configLink override
    // and override specified data
    const auto atts = cB.GetAttributes();
    const auto idIt = atts.find("id");
    if (idIt != atts.end()) {
      const auto configIt = fConfigMap.find(idIt->second);
      if (configIt != fConfigMap.end()) {
        const ConfigLink& readerLink = configIt->second;

        // guaranteed to exist by validation
        Branch originalBranch = readerLink.GetReader()->GetTopBranch();
        Branch replacementBranch = cB.GetFirstChild();
        if (replacementBranch)
          DescendAndReplace(replacementBranch, originalBranch);
        else {
          ostringstream msg;
          msg << "The <configLink> with attributes " << AsXML(cB.GetAttributes())
              << " has no children. No configuration data will be replaced for that <configLink>.";
          ERROR(msg);
          throw XMLParseException(msg.str());
        }

        // Revalidate the modified document
        ReaderStringInput readerFromStringInput(readerLink.GetReader()->GetTopBranch().String());
        Reader validationReader(readerFromStringInput, Reader::eSCHEMA);

      } else {
        ostringstream msg;
        msg << "The <parameterOverrides> portion of the bootstrap file specifies "
               "a <configLink> with " << AsXML(cB.GetAttributes()) << ", "
               "but no matching <configLink> is found in the bootstrap file.";
        ERROR(msg);
        throw XMLParseException(msg.str());
      }
    }
  }
}


void
CentralConfig::DescendAndReplace(Branch replacementBranch,
                                 Branch& originalBranch)
{
  while (replacementBranch) {

    const string replacementBranchName = replacementBranch.GetName();
    const string originalBranchName = originalBranch.GetName();
    AttributeMap replacementBranchAtts = replacementBranch.GetAttributes();
    const AttributeMap originalBranchAtts = originalBranch.GetAttributes();

    // skip units in branch selection
    // (units are a special attribute which are not selected upon)
    replacementBranchAtts.erase("unit");
    replacementBranchAtts.erase("UNIT");

    if (originalBranch.GetParent() &&  // skip the document node.
        (replacementBranchName != originalBranchName ||
         replacementBranchAtts != originalBranchAtts)) {
      originalBranch = originalBranch.GetSibling(replacementBranchName, replacementBranchAtts);
    }

    if (!originalBranch) {
      ostringstream msg;
      msg << "Failure while attempting to override configuration parameters. "
             "An override was requested for a branch "
              "<" << replacementBranchName << AsXML(replacementBranchAtts) << "> "
             "but a branch "
             "<" << originalBranchName << AsXML(originalBranchAtts) << "> "
             "was found instead at this place in the original configuration file.";
      ERROR(msg);
      throw XMLParseException(msg.str());
    }

    string replacementData;
    replacementBranch.GetData(replacementData);

    // unsupported case mentioned above
    if (replacementBranch.GetFirstChild() && !replacementData.empty()) {
      ostringstream msg;
      msg << "Problem encountered while trying to replace branch "
             "<" << originalBranchName << AsXML(originalBranchAtts) << "> "
             "with branch "
             "<" << replacementBranchName << AsXML(replacementBranchAtts) << ">. "
             "Note that replacing a branch, which contains both data and "
             "sub-branches, is not supported.";
      WARNING(msg);
      throw XMLParseException(msg.str());
    }

    if (!replacementData.empty()) {

      if (replacementBranch.GetFirstChild()) {
        ostringstream msg;
        msg << "Problem encountered while trying to replace branch "
               "<" << originalBranchName << AsXML(originalBranchAtts) << "> "
               "with branch "
               "<" << replacementBranchName << AsXML(replacementBranchAtts) << ">. "
               "Cannot replace a branch which contains both data and sub-branches.";
        WARNING(msg);
        throw XMLParseException(msg.str());
      }

      const auto dom = originalBranch.GetDOMNode();

      if (dom->getChildNodes()->getLength() != 1) {
        ostringstream msg;
        msg << "The data in the original branch "
               "<" << originalBranchName << AsXML(originalBranchAtts) << "> "
               "is unexpectedly split-up into several strings (probably by a comment) and thus "
               "cannot be simply replaced with the string of the replacement branch "
               "<" << replacementBranchName << AsXML(replacementBranchAtts) << ">. "
               "Please remove any comments in the data string of the original branch.\n"
               "original branch = ";
        auto c = dom->getFirstChild();
        if (!c)
          msg << "\"\"";
        else {
          msg << '"' << fwk::AsString(*c) << '"';
          for ( ; c; c = c->getNextSibling())
            msg << " + \"" << fwk::AsString(*c) << '"';
        }
        msg << "\nreplacement branch = \"" << replacementBranch.Get<string>() << '"';
        ERROR(msg);
        throw XMLParseException(msg.str());
      }

      const auto doc = dom->getOwnerDocument();
      // replace text in the node
      const auto replacementText =
        doc->createTextNode(XercesPtrX(XMLString::transcode(replacementData.c_str())).Get());
      // actual branch replacement starts here
      dom->replaceChild(replacementText, dom->getFirstChild())->release();

      // replace the unit attribute of the node, if there is one
      DOMAttr* replacementUnitAtt = nullptr;
      DOMElement* const replacementElement = dynamic_cast<DOMElement*>(replacementBranch.GetDOMNode());
      const XMLCh* replacementUnit = nullptr;

      if (replacementElement) {
        const XercesPtrX attrName(XMLString::transcode("unit"));
        replacementUnitAtt = replacementElement->getAttributeNode(attrName.Get());
        if (!replacementUnitAtt) {
          const XercesPtrX attrName(XMLString::transcode("UNIT"));
          replacementUnitAtt = replacementElement->getAttributeNode(attrName.Get());
        }
      }
      if (replacementUnitAtt)
        replacementUnit = replacementUnitAtt->getValue();

      DOMAttr* originalUnitAtt = nullptr;
      DOMElement* const originalElement = dynamic_cast<DOMElement*>(originalBranch.GetDOMNode());

      if (originalElement) {
        const XercesPtrX attrName(XMLString::transcode("unit"));
        originalUnitAtt = originalElement->getAttributeNode(attrName.Get());
        if (!originalUnitAtt) {
          const XercesPtrX attrName(XMLString::transcode("UNIT"));
          originalUnitAtt = originalElement->getAttributeNode(attrName.Get());
        }
      }
      if (originalUnitAtt && replacementUnitAtt)
        originalUnitAtt->setValue(replacementUnit);
      // Replacement ends here
    }

    // descend to next level in the hierarchy
    Branch replacementChild = replacementBranch.GetFirstChild();
    Branch originalChild = originalBranch.GetFirstChild();
    if (replacementChild && originalChild)
      DescendAndReplace(replacementChild, originalChild);

    replacementBranch = replacementBranch.GetNextSibling();
  } // while
}


void
CentralConfig::CheckFingerprints(const bool fingerprintFatal)
{
  // Fill the Fingerprint map generated at config time, if necessary
  if (!fConfigTimeFingerMap.size())
    FillConfigTimeFingerMap();

  list<string> multipleMD5List;

  for (const auto& runConfig : fConfigMap) {

    if (fMd5Excludes.find(runConfig.first) != fMd5Excludes.end())
      continue;

    const string& linkName = runConfig.second.GetLink();

    // Don't attempt to compute the md5 if the config link is an Xpath.
    // In such a case, the config file has been concatenated into a log
    // which will have already been checked at the time said log
    // was generated.
    if (linkName.empty() || linkName[0] == '#')
      continue;

    const auto cmd = "openssl dgst -md5 " + linkName;

    namespace bp = boost::process;
    bp::ipstream is;
    bp::child pipe(cmd, bp::std_out > is);
    typedef std::istreambuf_iterator<char> IstrIt;
    const std::string fullOut{IstrIt{is}, IstrIt{}};
    pipe.wait();
    if (pipe.exit_code())
      WARNING(str(boost::format("checksum command `%1%` returned status %2%") % cmd % pipe.exit_code()));

    if (fullOut.empty()) {
      WARNING("received no output from '" + cmd + "'");
      continue;
    }

    string runFinger = fullOut.substr(fullOut.find("=") + 1);
    boost::trim(runFinger);

    // Find the fingerprint for this run-time config file in the fingerprint map
    // generated at configuration time.  Paths are currently
    // stripped off both the run-time config file name and the
    // filename read at configure time.

    const auto start = linkName.rfind("/") + 1;
    const auto length = linkName.rfind(".xml") - start;
    const string strippedName = linkName.substr(start, length);

    const auto fileMatch = fConfigTimeFingerMap.equal_range(strippedName);
    int nFilenameMatches = 0;
    bool fingerprintMatch = false;
    for (auto fingerIt = fileMatch.first; fingerIt != fileMatch.second; ++fingerIt) {
      ++nFilenameMatches;
      if (fingerIt->second == runFinger)
        fingerprintMatch = true;
    }

    if (!nFilenameMatches)
      fNoMd5List.push_back(strippedName);
    else if (nFilenameMatches > 1)
      multipleMD5List.push_back(strippedName);
    else if (!fingerprintMatch)
      fMismatchedMd5List.push_back(strippedName);

  }

  // Warn about missing MD5s
  if (!fNoMd5List.empty()) {
    ostringstream msg;
    msg << "No configuration-time MD5 fingerprint found for the following configuration files. "
        << "Checking the validity of these configuration files is impossible.";
    for (const auto& file : fNoMd5List)
      msg << "\n  - " << file;
    WARNING(msg);
  }

  // Warn about multiple MD5s
  if (!multipleMD5List.empty()) {
    ostringstream msg;
    msg << "More than one configuration-time md5 fingerprint found corresponding to each of the "
        << "following configuration files. If at least one matching fingerprint is found, I "
        << "will continue execution. But you have been warned.";
    for (const auto& file : multipleMD5List)
      msg << "\n  - " << file;
    WARNING(msg);
  }

  // Bitterly complain about mismatching MD5s
  if (!fMismatchedMd5List.empty()) {
    ostringstream msg;
    msg << "Incorrect MD5 fingerprints were found for the following configuration files. "
        << "This implies this configuration file has been altered.";
    for (const auto& file : fMismatchedMd5List)
      msg << "\n  - " << file;
    if (fingerprintFatal) {
      ERROR(msg);
      throw InvalidConfigurationException(msg.str());
    } else
      WARNING(msg);
  }
}


void
CentralConfig::WriteConfig(const string& fileName)
{
  ofstream out(fileName.c_str());
  out << GetConfig();
}


string
CentralConfig::GetConfig()
{
  // poor-man's lazy evaluation, to avoid adding to the config
  // stream if GetConfig is called multiple times
  // This should probably be replaced with something better.
  if (fConfigInfoIsValid)
    return fConfigInfo.str();
  fConfigInfoIsValid = true;

  // stylesheet to browse
  // (removing stylesheet because it is unmaintained.. tp 2 July 07)
  //  fConfigInfo << "<?xml-stylesheet href=\""
  //              << LOGSTYLESHEETDIR << "/LogStyleSheet.xsl\" type=\"text/xsl\"?>\n\n"

  fConfigInfo << "<?xml version='1.0' encoding='iso-8859-1'?>\n"
    "<bootstrap xmlns:xlink=\"http://www.auger.org/schema/types\">\n"
    "<header>\n"
    "<softwareVersion> " << OFFLINE_PACKAGE_STRING << " </softwareVersion>\n"
    "<GITGlobalRevision> " << GITGlobalRevision::GetInstance().GetId() << " </GITGlobalRevision>\n";

  if (fNoMd5List.size()) {
    fConfigInfo << "<noMd5> <!-- no md5 fingerprint was found for these config files -->\n";
    for (const auto& file : fNoMd5List)
      fConfigInfo << "  " << file << '\n';
    fConfigInfo << "</noMd5>\n";
  }
  if (fMismatchedMd5List.size()) {
    fConfigInfo << "<mismatchedMd5> "
                   "<!-- the md5 fingerprints for these config files do not match the defaults -->\n";
    for (const auto& file : fMismatchedMd5List)
      fConfigInfo << "  " << file << '\n';
    fConfigInfo << "</mismatchedMd5>\n";
  }

  fConfigInfo << "<moduleVersions>\n";

  const auto& usedModules = RunController::GetInstance().GetUsedModuleNames();
  for (const auto& name : usedModules) {
    VModule& mod = RunController::GetInstance().GetModule(name);
    fConfigInfo
      << "  <module>\n"
         "    <logicalName> " << name <<  " </logicalName>\n"
         "    <lastSVNRevision> " << mod.GetVersionInfo(VModule::eRevisionNumber) << " </lastSVNRevision>\n"
         "    <lastRevisionDate> " << mod.GetVersionInfo(VModule::eDate) << " </lastRevisionDate>\n"
         "    <lastEditor> " << mod.GetVersionInfo(VModule::eLastEditor) << " </lastEditor>\n"
         "  </module>\n";
  }

  fConfigInfo << "</moduleVersions>\n"
                 "</header>\n"
                 "<centralConfig>\n";
  LogBootstrap();
  fConfigInfo << "</centralConfig>\n";

  for (const auto& conf : fUsedConfigs) {

    const auto used = fConfigMap.find(conf);
    if (used != fConfigMap.end()) {

      // Here we fiddle the document tag such that no namespace or schema
      // stuff appears in it.  This is necessary, since otherwise the
      // readback gets confused and throws exceptions.  It appears that
      // namespace/schema related attributes can only be in the very top
      // document tag.
      Branch topB = used->second.GetReader()->GetTopBranch();
      fConfigInfo << '<' << conf << ">\n"
                     "  <" << topB.GetName() << ">\n";  // drops any attributes

      for (auto b = topB.GetFirstChild(); b; b = b.GetNextSibling())
        fConfigInfo << AsString(b, 4);

      fConfigInfo << "  </" << topB.GetName() << ">\n"
                     "</" << conf << ">\n";

    }

  }

  fConfigInfo << "</bootstrap>\n";

  return fConfigInfo.str();
}


// called from GetConfig

void
CentralConfig::LogBootstrap()
{
  for (auto ccB = fBootstrapReader->GetTopBranch().GetFirstChild(); ccB; ccB = ccB.GetNextSibling()) {
    if (ccB.GetName() == "centralConfig" || ccB.GetName() == "defaultConfig") {
      ostringstream attributes;
      for (auto cLink = ccB.GetFirstChild(); cLink; cLink = cLink.GetNextSibling()) {
        const auto attr = cLink.GetAttributes();
        const string& id = attr.find("id")->second;
        for (const auto& a : attr) {
          attributes << ' ' << a.first << "=\"";
          if (a.first == "xlink:href")
            attributes << '#' << id;
          else
            attributes << a.second;
          attributes << '"';
        }
        for (const auto& c : fUsedConfigs) {
          if (id == c) {
            fConfigInfo << " <" << cLink.GetName() << attributes.str() << "/>\n";
            break;
          }
        }
        attributes.str("");
      }
    }
  }
}


Branch
CentralConfig::Find(std::string path)
{
  string name;
  Branch branch = fBootstrapReader->GetTopBranch();
  while (path.find("/") != string::npos) {
    name = path.substr(0, path.find("/"));
    path = path.substr(path.find("/") + 1);
    branch = branch.GetChild(name);
  }
  branch = branch.GetChild(path);
  return branch;
}


string
CentralConfig::AsString(const Branch& branch, const int indent, const int indentIncrement)
{
  stringstream contents;

  contents << string(indent, ' ') << '<' << branch.GetName();

  stringstream attrString;
  for (const auto& a : branch.GetAttributes())
    attrString << ' ' << a.first << "=\"" << a.second << '\"';
  contents << attrString.str() << '>';

  Branch child = branch.GetFirstChild();
  if (!child) {
    // one-liner
    contents << ' ' << branch.Get<string>() << ' ' << "</" << branch.GetName() << ">\n";
  } else {
    // recurse
    contents << '\n';
    do {
      contents << AsString(child, indent + indentIncrement, indentIncrement);
      child = child.GetNextSibling();
    } while (child);
    contents << string(indent, ' ') << "</" << branch.GetName() << ">\n";
  }

  return contents.str();
}


CentralConfig::IdIterator
CentralConfig::IdsBegin()
{
  return CentralConfig::IdIterator(fConfigMap.begin());
}


CentralConfig::IdIterator
CentralConfig::IdsEnd()
{
  return CentralConfig::IdIterator(fConfigMap.end());
}


void
CentralConfig::AbortParse(const string& s)
{
  ostringstream msg;
  msg << "Aborting configuration because of parse error. " << s;
  ERROR(msg);
  throw XMLParseException(msg.str());
}