/*=========================================================================

  Program:   CMake - Cross-Platform Makefile Generator
  Module:    $RCSfile$
  Language:  C++
  Date:      $Date$
  Version:   $Revision$

  Copyright (c) 2002 Kitware, Inc., Insight Consortium.  All rights reserved.
  See Copyright.txt or http://www.cmake.org/HTML/Copyright.html for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notices for more information.

=========================================================================*/
#include "cmDefinitions.h"

//----------------------------------------------------------------------------
cmDefinitions::Def cmDefinitions::NoDef;

//----------------------------------------------------------------------------
cmDefinitions::cmDefinitions(cmDefinitions* parent): Up(parent)
{
}

//----------------------------------------------------------------------------
void cmDefinitions::Reset(cmDefinitions* parent)
{
  this->Up = parent;
  this->Map.clear();
}

//----------------------------------------------------------------------------
cmDefinitions::Def const&
cmDefinitions::GetInternal(const char* key)
{
  MapType::const_iterator i = this->Map.find(key);
  if(i != this->Map.end())
    {
    return i->second;
    }
  else if(cmDefinitions* up = this->Up)
    {
    // Query the parent scope and store the result locally.
    Def def = up->GetInternal(key);
    return this->Map.insert(MapType::value_type(key, def)).first->second;
    }
  return this->NoDef;
}

//----------------------------------------------------------------------------
cmDefinitions::Def const&
cmDefinitions::SetInternal(const char* key, Def const& def)
{
  if(this->Up || def.Exists)
    {
    // In lower scopes we store keys, defined or not.
    MapType::iterator i = this->Map.find(key);
    if(i == this->Map.end())
      {
      i = this->Map.insert(MapType::value_type(key, def)).first;
      }
    else
      {
      i->second = def;
      }
    return i->second;
    }
  else
    {
    // In the top-most scope we need not store undefined keys.
    this->Map.erase(key);
    return this->NoDef;
    }
}

//----------------------------------------------------------------------------
const char* cmDefinitions::Get(const char* key)
{
  Def const& def = this->GetInternal(key);
  return def.Exists? def.c_str() : 0;
}

//----------------------------------------------------------------------------
const char* cmDefinitions::Set(const char* key, const char* value)
{
  Def const& def = this->SetInternal(key, Def(value));
  return def.Exists? def.c_str() : 0;
}

//----------------------------------------------------------------------------
cmDefinitions cmDefinitions::Closure() const
{
  return cmDefinitions(ClosureTag(), this);
}

//----------------------------------------------------------------------------
cmDefinitions::cmDefinitions(ClosureTag const&, cmDefinitions const* root):
  Up(0)
{
  std::set<cmStdString> undefined;
  this->ClosureImpl(undefined, root);
}

//----------------------------------------------------------------------------
void cmDefinitions::ClosureImpl(std::set<cmStdString>& undefined,
                                cmDefinitions const* defs)
{
  // Consider local definitions.
  for(MapType::const_iterator mi = defs->Map.begin();
      mi != defs->Map.end(); ++mi)
    {
    // Use this key if it is not already set or unset.
    if(this->Map.find(mi->first) == this->Map.end() &&
       undefined.find(mi->first) == undefined.end())
      {
      if(mi->second.Exists)
        {
        this->Map.insert(*mi);
        }
      else
        {
        undefined.insert(mi->first);
        }
      }
    }

  // Traverse parents.
  if(cmDefinitions const* up = defs->Up)
    {
    this->ClosureImpl(undefined, up);
    }
}

//----------------------------------------------------------------------------
std::set<cmStdString> cmDefinitions::ClosureKeys() const
{
  std::set<cmStdString> defined;
  std::set<cmStdString> undefined;
  this->ClosureKeys(defined, undefined);
  return defined;
}

//----------------------------------------------------------------------------
void cmDefinitions::ClosureKeys(std::set<cmStdString>& defined,
                                std::set<cmStdString>& undefined) const
{
  // Consider local definitions.
  for(MapType::const_iterator mi = this->Map.begin();
      mi != this->Map.end(); ++mi)
    {
    // Use this key if it is not already set or unset.
    if(defined.find(mi->first) == defined.end() &&
       undefined.find(mi->first) == undefined.end())
      {
      std::set<cmStdString>& m = mi->second.Exists? defined : undefined;
      m.insert(mi->first);
      }
    }

  // Traverse parents.
  if(cmDefinitions const* up = this->Up)
    {
    up->ClosureKeys(defined, undefined);
    }
}
