// src/backend/resource_policies_gatekeeper.cc - Copyright 2005, 2006, University
//               of Padova, dept. of Pure and Applied
//               Mathematics
//
// This file is part of SGPEMv2.
//
// This is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// SGPEMv2 is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with SGPEMv2; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

#include "config.h"

#include "resource_policies_gatekeeper.hh"
#include "resource_policy_manager.hh"
#include "resource_policy.hh"

// Include full template definition only in implementation files:
#include "singleton.tcc"

#include <algorithm>
#include <cassert>

using std::vector;
using std::map;
using std::find;
using std::runtime_error;
using namespace sgpem;

// Explicit template instantiation to allow to export symbols from the DSO.
template class SG_DLLEXPORT Singleton<ResourcePoliciesGatekeeper>;

typedef vector<ResourcePolicyManager*>::iterator ManagerIterator;
typedef map<History*, ResourcePolicy*>::iterator PolicyIterator;

const vector<ResourcePolicyManager*>&
ResourcePoliciesGatekeeper::get_registered() const
{
  return _registered;
}

void
ResourcePoliciesGatekeeper::register_manager(ResourcePolicyManager* manager)
{
  assert(manager != NULL);

  ManagerIterator end = _registered.end();

  if (find(_registered.begin(), end, manager) == end)
    _registered.push_back(manager);
}

void
ResourcePoliciesGatekeeper::unregister_manager(ResourcePolicyManager* manager)
{
  assert(manager != NULL);

  ManagerIterator end = _registered.end();
  ManagerIterator pos = find(_registered.begin(), end, manager);

  if (pos != end)
  {
    deactivate_policies(**pos);
    _registered.erase(pos);
  }
}

ResourcePolicy&
ResourcePoliciesGatekeeper::get_current_policy(History* history) throw(runtime_error)
{
  assert(history != NULL);

  PolicyIterator policy = _active_policies.find(history);

  if (policy == _active_policies.end())
    throw runtime_error("No active policy associated with this "
                        "history is available.");

  return *policy->second;
}

void
ResourcePoliciesGatekeeper::activate_policy(History *history, ResourcePolicy* policy)
{
  assert(history != NULL && policy != NULL);

  _active_policies[history] = policy;
}

ResourcePoliciesGatekeeper::ResourcePoliciesGatekeeper()
{}

void
ResourcePoliciesGatekeeper::deactivate_policies(const ResourcePolicyManager& manager)
{
  typedef vector<ResourcePolicy*>::const_iterator AvailableIt;

  const vector<ResourcePolicy*>& policies = manager.get_avail_policies();

  for (AvailableIt avail_it = policies.begin(); avail_it != policies.end(); ++avail_it)
  {
    for (PolicyIterator it = _active_policies.begin(); it != _active_policies.end();)
      if (it->second == *avail_it)
        // Please note the postfix increment (operating
	// on the old iterator, now invalidated by erase)
        _active_policies.erase(it++);
      else
        ++it;
  } //~ for(avail_it)
}