/*============================================================================
  CMake - Cross Platform Makefile Generator
  Copyright 2012 Stephen Kelly <steveire@gmail.com>

  Distributed under the OSI-approved BSD License (the "License");
  see accompanying file Copyright.txt for details.

  This software is distributed WITHOUT ANY WARRANTY; without even the
  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  See the License for more information.
============================================================================*/

#include "cmGeneratorExpressionDAGChecker.h"

#include "cmMakefile.h"

//----------------------------------------------------------------------------
cmGeneratorExpressionDAGChecker::cmGeneratorExpressionDAGChecker(
                const cmListFileBacktrace &backtrace,
                const std::string &target,
                const std::string &property,
                const GeneratorExpressionContent *content,
                cmGeneratorExpressionDAGChecker *parent)
  : Parent(parent), Target(target), Property(property),
    Content(content), Backtrace(backtrace)
{
  this->IsDAG = this->isDAG();
}

//----------------------------------------------------------------------------
bool cmGeneratorExpressionDAGChecker::check() const
{
  return this->IsDAG;
}

//----------------------------------------------------------------------------
void cmGeneratorExpressionDAGChecker::reportError(
                  cmGeneratorExpressionContext *context,
                  const std::string &expr)
{
  if (this->IsDAG)
    {
    return;
    }

  context->HadError = true;
  if (context->Quiet)
    {
    return;
    }

  const cmGeneratorExpressionDAGChecker *parent = this->Parent;

  if (parent && !parent->Parent)
    {
    cmOStringStream e;
    e << "Error evaluating generator expression:\n"
      << "  " << expr << "\n"
      << "Self reference on target \""
      << context->Target->GetName() << "\".\n";
    context->Makefile->GetCMakeInstance()
      ->IssueMessage(cmake::FATAL_ERROR, e.str().c_str(),
                      parent->Backtrace);
    return;
    }

  {
  cmOStringStream e;
  e << "Error evaluating generator expression:\n"
    << "  " << expr << "\n"
    << "Dependency loop found.";
  context->Makefile->GetCMakeInstance()
    ->IssueMessage(cmake::FATAL_ERROR, e.str().c_str(),
                    context->Backtrace);
  }

  int loopStep = 1;
  while (parent)
    {
    cmOStringStream e;
    e << "Loop step " << loopStep << "\n"
      << "  "
      << (parent->Content ? parent->Content->GetOriginalExpression() : expr)
      << "\n";
    context->Makefile->GetCMakeInstance()
      ->IssueMessage(cmake::FATAL_ERROR, e.str().c_str(),
                      parent->Backtrace);
    parent = parent->Parent;
    ++loopStep;
    }
}

//----------------------------------------------------------------------------
bool cmGeneratorExpressionDAGChecker::isDAG() const
{
  const cmGeneratorExpressionDAGChecker *parent = this->Parent;
  while (parent)
    {
    if (this->Target == parent->Target && this->Property == parent->Property)
      {
      return false;
      }
    parent = parent->Parent;
    }
  return true;
}