// Copyright (c) 1994 James Clark

// See the file COPYING for copying permission.

#include "splib.h"

#include "DescriptorManager.h"

#include "ListIter.h"

#ifdef SP_NAMESPACE

namespace SP_NAMESPACE {

#endif

DescriptorUser::DescriptorUser(DescriptorManager *manager)

: manager_(manager)

{

  if (manager_)

    manager_->addUser(this);

}

DescriptorUser::~DescriptorUser()

{

  if (manager_)

    manager_->removeUser(this);

}

void DescriptorUser::managerDeleted()

{

  manager_ = 0;

}

Boolean DescriptorUser::suspend()

{

  return 0;

}

void DescriptorUser::acquireD()

{

  if (manager_)

    manager_->acquireD();

}

void DescriptorUser::releaseD()

{

  if (manager_)

    manager_->releaseD();

}

DescriptorManager::DescriptorManager(int maxD)

: maxD_(maxD), usedD_(0)

{

}

DescriptorManager::~DescriptorManager()

{

  for (ListIter<DescriptorUser *> iter(users_);

       !iter.done();

       iter.next())

    iter.cur()->managerDeleted();

}

void DescriptorManager::addUser(DescriptorUser *p)

{

  users_.insert(p);

}

void DescriptorManager::removeUser(DescriptorUser *p)

{

  users_.remove(p);

}

void DescriptorManager::acquireD()

{

  if (usedD_ >= maxD_) {

    for (ListIter<DescriptorUser *> iter(users_);

	 !iter.done();

	 iter.next()) {

      if (iter.cur()->suspend())

	break;

    }

  }

  usedD_++;

}

void DescriptorManager::releaseD()

{

  usedD_--;

}

#ifdef SP_NAMESPACE

}

#endif