PluginService.cpp

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/*****************************************************************************\
* (c) Copyright 2013 CERN                                                     *
*                                                                             *
* This software is distributed under the terms of the GNU General Public      *
* Licence version 3 (GPL Version 3), copied verbatim in the file "LICENCE".   *
*                                                                             *
* In applying this licence, CERN does not waive the privileges and immunities *
* granted to it by virtue of its status as an Intergovernmental Organization  *
* or submit itself to any jurisdiction.                                       *
\*****************************************************************************/


#include <Gaudi/PluginService.h>

#include <dirent.h>
#include <dlfcn.h>

#include <cstdlib>
#include <fstream>
#include <iostream>
#include <memory>
#include <regex>

#include <cxxabi.h>
#include <sys/stat.h>

#if defined( __GXX_EXPERIMENTAL_CXX0X__ ) || __cplusplus >= 201103L
#define REG_SCOPE_LOCK std::lock_guard<std::recursive_mutex> _guard( m_mutex );

namespace
{
  std::mutex registrySingletonMutex;
}
#define SINGLETON_LOCK std::lock_guard<std::mutex> _guard(::registrySingletonMutex );
#else
#define REG_SCOPE_LOCK
#define SINGLETON_LOCK
#endif

#include <algorithm>

namespace
{
  // string trimming functions taken from
  // http://stackoverflow.com/questions/216823/whats-the-best-way-to-trim-stdstring

  constexpr struct is_space_t {
    bool operator()( int i ) const { return std::isspace( i ); }
  } is_space{};

  // trim from start
  static inline std::string& ltrim( std::string& s )
  {
    s.erase( s.begin(), std::find_if_not( s.begin(), s.end(), is_space ) );
    return s;
  }

  // trim from end
  static inline std::string& rtrim( std::string& s )
  {
    s.erase( std::find_if_not( s.rbegin(), s.rend(), is_space ).base(), s.end() );
    return s;
  }
  // trim from both ends
  static inline std::string& trim( std::string& s ) { return ltrim( rtrim( s ) ); }
}

namespace
{
  inline void factoryInfoSetHelper( std::string& dest, const std::string value, const std::string& desc,
                                    const std::string& id )
  {
    if ( dest.empty() ) {
      dest = value;
    } else if ( dest != value ) {
      Gaudi::PluginService::Details::logger().warning( "new factory loaded for '" + id + "' with different " + desc +
                                                       ": " + dest + " != " + value );
    }
  }

  struct OldStyleCnv {
    std::string name;
    void operator()( const char c )
    {
      switch ( c ) {
      case '<':
      case '>':
      case ',':
      case '(':
      case ')':
      case ':':
      case '.':
        name.push_back( '_' );
        break;
      case '&':
        name.push_back( 'r' );
        break;
      case '*':
        name.push_back( 'p' );
        break;
      case ' ':
        break;
      default:
        name.push_back( c );
        break;
      }
    }
  };
  std::string old_style_name( const std::string& name )
  {
    return std::for_each( name.begin(), name.end(), OldStyleCnv() ).name;
  }
}

namespace Gaudi
{
  namespace PluginService
  {

    Exception::Exception( std::string msg ) : m_msg( std::move( msg ) ) {}
    Exception::~Exception() throw() {}
    const char* Exception::what() const throw() { return m_msg.c_str(); }

    namespace Details
    {
      void* getCreator( const std::string& id, const std::string& type )
      {
        return Registry::instance().get( id, type );
      }

      std::string demangle( const std::string& id )
      {
        int status;
        auto realname = std::unique_ptr<char, decltype( free )*>(
            abi::__cxa_demangle( id.c_str(), nullptr, nullptr, &status ), free );
        if ( !realname ) return id;
#if _GLIBCXX_USE_CXX11_ABI
        return std::regex_replace(
            realname.get(),
            std::regex{"std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > ?"},
            "std::string" );
#else
        return std::string{realname.get()};
#endif
      }
      std::string demangle( const std::type_info& id ) { return demangle( id.name() ); }

      Registry& Registry::instance()
      {
        SINGLETON_LOCK
        static Registry r;
        return r;
      }

      Registry::Registry() : m_initialized( false ) {}

      void Registry::initialize()
      {
        REG_SCOPE_LOCK
        if ( m_initialized ) return;
        m_initialized = true;
#if defined( _WIN32 )
        const char* envVar = "PATH";
        const char sep     = ';';
#elif defined( __APPLE__ )
        const char* envVar = "DYLD_LIBRARY_PATH";
        const char sep     = ':';
#else
        const char* envVar = "LD_LIBRARY_PATH";
        const char sep     = ':';
#endif
        char* search_path = ::getenv( envVar );
        if ( search_path ) {
          logger().debug( std::string( "searching factories in " ) + envVar );
          std::string path( search_path );
          std::string::size_type pos    = 0;
          std::string::size_type newpos = 0;
          while ( pos != std::string::npos ) {
            std::string dirName;
            // get the next entry in the path
            newpos = path.find( sep, pos );
            if ( newpos != std::string::npos ) {
              dirName = path.substr( pos, newpos - pos );
              pos     = newpos + 1;
            } else {
              dirName = path.substr( pos );
              pos     = newpos;
            }
            logger().debug( std::string( " looking into " ) + dirName );
            // look for files called "*.components" in the directory
            DIR* dir = opendir( dirName.c_str() );
            if ( dir ) {
              struct dirent* entry;
              while ( ( entry = readdir( dir ) ) ) {
                std::string name( entry->d_name );
                // check if the file name ends with ".components"
                std::string::size_type extpos = name.find( ".components" );
                if ( ( extpos != std::string::npos ) && ( ( extpos + 11 ) == name.size() ) ) {
                  std::string fullPath = ( dirName + '/' + name );
                  { // check if it is a regular file
                    struct stat buf;
                    stat( fullPath.c_str(), &buf );
                    if ( !S_ISREG( buf.st_mode ) ) continue;
                  }
                  // read the file
                  logger().debug( std::string( "  reading " ) + name );
                  std::ifstream factories{fullPath};
                  std::string line;
                  int factoriesCount = 0;
                  int lineCount      = 0;
                  while ( !factories.eof() ) {
                    ++lineCount;
                    std::getline( factories, line );
                    trim( line );
                    // skip empty lines and lines starting with '#'
                    if ( line.empty() || line[0] == '#' ) continue;
                    // look for the separator
                    auto pos = line.find( ':' );
                    if ( pos == std::string::npos ) {
                      logger().warning( "failed to parse line " + fullPath + ':' + std::to_string( lineCount ) );
                      continue;
                    }
                    const std::string lib( line, 0, pos );
                    const std::string fact( line, pos + 1 );
                    m_factories.emplace( fact, FactoryInfo( lib ) );
#ifdef GAUDI_REFLEX_COMPONENT_ALIASES
                    // add an alias for the factory using the Reflex convention
                    std::string old_name = old_style_name( fact );
                    if ( fact != old_name ) {
                      FactoryInfo old_info( lib );
                      old_info.properties["ReflexName"] = "true";
                      m_factories.emplace( old_name, old_info );
                    }
#endif
                    ++factoriesCount;
                  }
                  if ( logger().level() <= Logger::Debug ) {
                    logger().debug( "  found " + std::to_string( factoriesCount ) + " factories" );
                  }
                }
              }
              closedir( dir );
            }
          }
        }
      }

      Registry::FactoryInfo& Registry::add( const std::string& id, void* factory, const std::string& type,
                                            const std::string& rtype, const std::string& className,
                                            const Properties& props )
      {
        REG_SCOPE_LOCK
        FactoryMap& facts = factories();
        auto entry        = facts.find( id );
        if ( entry == facts.end() ) {
          // this factory was not known yet
          entry = facts.emplace( id, FactoryInfo( "unknown", factory, type, rtype, className, props ) ).first;
        } else {
          // do not replace an existing factory with a new one
          if ( !entry->second.ptr ) entry->second.ptr = factory;
          factoryInfoSetHelper( entry->second.type, type, "type", id );
          factoryInfoSetHelper( entry->second.rtype, rtype, "return type", id );
          factoryInfoSetHelper( entry->second.className, className, "class", id );
        }
#ifdef GAUDI_REFLEX_COMPONENT_ALIASES
        // add an alias for the factory using the Reflex convention
        std::string old_name = old_style_name( id );
        if ( id != old_name ) add( old_name, factory, type, rtype, className, props ).properties["ReflexName"] = "true";
#endif
        return entry->second;
      }

      void* Registry::get( const std::string& id, const std::string& type ) const
      {
        REG_SCOPE_LOCK
        const FactoryMap& facts = factories();
        auto f                  = facts.find( id );
        if ( f != facts.end() ) {
#ifdef GAUDI_REFLEX_COMPONENT_ALIASES
          const Properties& props = f->second.properties;
          if ( props.find( "ReflexName" ) != props.end() )
            logger().warning( "requesting factory via old name '" + id + "'"
                                                                         "use '" +
                              f->second.className + "' instead" );
#endif
          if ( !f->second.ptr ) {
            if ( !dlopen( f->second.library.c_str(), RTLD_LAZY | RTLD_GLOBAL ) ) {
              logger().warning( "cannot load " + f->second.library + " for factory " + id );
              char* dlmsg = dlerror();
              if ( dlmsg ) logger().warning( dlmsg );
              return nullptr;
            }
            f = facts.find( id ); // ensure that the iterator is valid
          }
          if ( f->second.type == type ) return f->second.ptr;
          logger().warning( "found factory " + id + ", but of wrong type: " + demangle( f->second.type ) +
                            " instead of " + demangle( type ) );
        }
        return nullptr; // factory not found
      }

      const Registry::FactoryInfo& Registry::getInfo( const std::string& id ) const
      {
        REG_SCOPE_LOCK
        static const FactoryInfo unknown( "unknown" );
        const FactoryMap& facts = factories();
        auto f                  = facts.find( id );
        return ( f != facts.end() ) ? f->second : unknown;
      }

      Registry& Registry::addProperty( const std::string& id, const std::string& k, const std::string& v )
      {
        REG_SCOPE_LOCK
        FactoryMap& facts                               = factories();
        auto f                                          = facts.find( id );
        if ( f != facts.end() ) f->second.properties[k] = v;
        return *this;
      }

      std::set<Registry::KeyType> Registry::loadedFactories() const
      {
        REG_SCOPE_LOCK
        const FactoryMap& facts = factories();
        std::set<KeyType> l;
        for ( const auto& f : facts ) {
          if ( f.second.ptr ) l.insert( f.first );
        }
        return l;
      }

      void Logger::report( Level lvl, const std::string& msg )
      {
        static const char* levels[] = {"DEBUG  : ", "INFO   : ", "WARNING: ", "ERROR  : "};
        if ( lvl >= level() ) {
          std::cerr << levels[lvl] << msg << std::endl;
        }
      }

      static std::unique_ptr<Logger> s_logger( new Logger );
      Logger& logger() { return *s_logger; }
      void setLogger( Logger* logger ) { s_logger.reset( logger ); }

    } // namespace Details

    void SetDebug( int debugLevel )
    {
      using namespace Details;
      Logger& l = logger();
      if ( debugLevel > 1 )
        l.setLevel( Logger::Debug );
      else if ( debugLevel > 0 )
        l.setLevel( Logger::Info );
      else
        l.setLevel( Logger::Warning );
    }

    int Debug()
    {
      using namespace Details;
      switch ( logger().level() ) {
      case Logger::Debug:
        return 2;
      case Logger::Info:
        return 1;
      default:
        return 0;
      }
    }
  }
} // namespace Gaudi::PluginService