EnvVars.cpp

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#include "blocxx/BLOCXX_config.h"
#include "blocxx/EnvVars.hpp"

#include <algorithm>
#include <cstring>

#if defined(OW_DARWIN)
// On MacOSX, environ is not defined in shared libraries.  It is only provided
// for executables.  Since the linker must resolve all symbols at link time,
// the normal extern declaration of environ won't work.  As a substitute, we
// need to use this:
#include <crt_externs.h>
#define environ (*_NSGetEnviron())

// For more details on the subject, follow one of these links:
// http://lists.gnu.org/archive/html/bug-guile/2004-01/msg00013.html
// http://lists.apple.com/archives/darwin-dev/2005/Mar/msg00132.html
// http://www.metapkg.org/wiki/15 (under the linking problems)

#else /* !DARWIN */
// according to man environ:
// This variable must be declared in the user program, but is
// declared in the header file unistd.h in case the header files came from
// libc4 or libc5, and in case they came from glibc and _GNU_SOURCE was
// defined.
extern char** environ;
#endif

namespace BLOCXX_NAMESPACE
{

namespace
{

void getKeyValue(
   const char *const strArg, 
   String& key, 
   String& value)
{
   key.erase();
   value.erase();

   const char* p = ::strchr(strArg, '=');
   if(p)
   {
      key = String(strArg, size_t(p-strArg));
      value = p+1;
   }
}

inline bool isValidKey(const String &key)
{
    //
    // SUSv3 specifies that the setenv() function shall fail,
    // if the environment variable name is NULL, empty or
    // contains a '=' character:
    //
    return key.length() && key.indexOf('=') == String::npos;
}

}  // End of anonymous namespace

EnvVars::EnvVars(EEnvVarFlag flag)
   : m_envMap()
   , m_envp(0)
{
   if(flag == E_CURRENT_ENVIRONMENT)
   {
      fillEnvMap(environ, m_envMap);
   }
}

EnvVars::EnvVars(const char* const envp[])
   : m_envMap()
   , m_envp(0)
{
   fillEnvMap(envp, m_envMap);
}

EnvVars::~EnvVars()
{
   deleteEnvp();
}

// STATIC
void 
EnvVars::fillEnvMap(EnvMap& envMap)
{
   fillEnvMap(environ, envMap);
}

// STATIC
void 
EnvVars::fillEnvMap(const char* const envp[], EnvMap& envMap)
{
   envMap.clear();
   String key, value;
   for(size_t i = 0; envp[i]; i++)
   {
      getKeyValue(envp[i], key, value);
      if(isValidKey(key))
      {
         envMap[key] = value;
      }
   }
}

void 
EnvVars::deleteEnvp() const
{
   if(m_envp)
   {
      int i;
   
      // Delete all char pointers env var array
      for(i = 0; m_envp[i]; i++)
      {
         // m_envp[i] may be null if deleteEnvp was called because an
         // exception was caught while trying to allocate the array
         // in getenvp()
         delete [] m_envp[i];
      }

      delete [] m_envp;    // Delete pointer array
      m_envp = 0;
   }
}

String 
EnvVars::getValue(const String& key, 
   const String& notFoundRetVal) const
{
   EnvMap::const_iterator it = m_envMap.find(key);
   return (it != m_envMap.end()) ? it->second : notFoundRetVal;
}

const char* const* 
EnvVars::getenvp() const
{
   if(!m_envp)
   {
      int i;
      m_envp = new char* [m_envMap.size()+1];
      std::fill(m_envp, m_envp+m_envMap.size()+1, (char*)0);
      try
      {
         EnvMap::const_iterator it = m_envMap.begin();
         for(i = 0; it != m_envMap.end(); i++, it++)
         {
            size_t klen = it->first.length();
            size_t vlen = it->second.length();

            m_envp[i] = new char[klen + vlen + 2];
            ::strcpy(m_envp[i], it->first.c_str());
            m_envp[i][klen] = '=';
            ::strcpy(m_envp[i]+klen+1, it->second.c_str());
         }
      }
      catch(...)
      {
         deleteEnvp();  // Delete what has been allocated thus far.
         throw;         // Re-throw this exception
      }
   }

   return m_envp;
}

bool 
EnvVars::removeVar(const String& varName)
{
   bool cc = false;
   EnvMap::iterator it = m_envMap.find(varName);
   if (it != m_envMap.end())
   {
      cc = true;
      deleteEnvp();
      m_envMap.erase(it);
   }

   return cc;
}

bool 
EnvVars::addVar(const String& name, const String& value)
{
   bool cc = false;
   if(isValidKey(name) && m_envMap.find(name) == m_envMap.end())
   {
      cc = true;
      deleteEnvp();
      m_envMap[name] = value;
   }
   return cc;
}

bool 
EnvVars::setVar(const String& key, const String& value)
{
   bool cc = false;
   if( isValidKey(key))
   {
      cc = true;
      deleteEnvp();
      m_envMap[key] = value;
   }
   return cc;
}

bool 
EnvVars::setVar(const String& keyValue)
{
   String key, value;
   getKeyValue(keyValue.c_str(), key, value);
   return setVar(key, value);
}

bool 
EnvVars::updateVar(const String& name, const String& value)
{
   bool cc = false;
   EnvMap::iterator it = m_envMap.find(name);
   if (it != m_envMap.end())
   {
      cc = true;
      deleteEnvp();
      it->second = value;
   }

   return cc;
}

}  // End of BLOCXX_NAMESPACE

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