Environment.cpp

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/***********************************************************************************\
* (c) Copyright 1998-2025 CERN for the benefit of the LHCb and ATLAS collaborations *
*                                                                                   *
* This software is distributed under the terms of the Apache version 2 licence,     *
* copied verbatim in the file "LICENSE".                                            *
*                                                                                   *
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* granted to it by virtue of its status as an Intergovernmental Organization        *
* or submit itself to any jurisdiction.                                             *
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#include <GaudiKernel/Environment.h>
#include <GaudiKernel/System.h>
#include <cstdlib>
 
namespace {
  std::string i_resolve( std::string& source, int recursions ) {
    if ( recursions > 0 ) {
      int lvl = 0, mx_lvl = 0;
      for ( const char *c = source.c_str(), *beg = nullptr; *c != 0; ++c ) {
        switch ( *c ) {
        case '$':
          if ( *( c + 1 ) == '{' ) {
            lvl++;
            if ( lvl > mx_lvl ) {
              mx_lvl = lvl;
              beg    = c;
            }
            c += 2;
          }
          break;
        case '}':
          if ( lvl == mx_lvl ) {
            std::string env( beg + 2, c - beg - 2 );
            std::string rep;
            if ( !System::getEnv( env.c_str(), rep ) ) rep = i_resolve( env, --recursions );
            if ( rep.length() ) {
              std::string e( beg, c - beg + 1 );
              size_t      idx = std::string::npos;
              while ( ( idx = source.find( e ) ) != std::string::npos ) { source.replace( idx, e.length(), rep ); }
              return i_resolve( source, --recursions );
            } else {
              // error: environment cannot be resolved....
              // Try to continue, but there is not too much hope.
            }
          }
          lvl--;
          break;
        default:
          break;
        }
      }
    }
    return source;
  }
} // namespace
 
StatusCode System::resolveEnv( const std::string& var, std::string& res, int recursions ) {
  std::string source = var;
  res                = i_resolve( source, recursions );
  if ( res.find( "${" ) == std::string::npos ) { return StatusCode::SUCCESS; }
  return StatusCode::FAILURE;
}
 
std::string System::homeDirectory() {
  // Return the user's home directory.
  std::string home_dir = "./";
  // Try to replace the current value with the content of several
  // environment variables
  System::getEnv( "home", home_dir ) || System::getEnv( "HOME", home_dir );
  return home_dir;
}
 
std::string System::tempDirectory() {
  // Return a user configured or systemwide directory to create
  // temporary files in.
  std::string dir;
  if ( System::getEnv( "TEMP", dir ) || System::getEnv( "TEMPDIR", dir ) || System::getEnv( "TEMP_DIR", dir ) ||
       System::getEnv( "TMP", dir ) || System::getEnv( "TMPDIR", dir ) || System::getEnv( "TMP_DIR", dir ) )
    return dir;
  else
    return homeDirectory();
}