/*

 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#include "logging/logLevel.hpp"

#include "logging/logOutputList.hpp"

#include "memory/allocation.inline.hpp"

#include "runtime/atomic.inline.hpp"

#include "runtime/orderAccess.inline.hpp"

#include "utilities/globalDefinitions.hpp"

jint LogOutputList::increase_readers() {

  jint result = Atomic::add(1, &_active_readers);

  assert(_active_readers > 0, "Ensure we have consistent state");

  return result;

}

jint LogOutputList::decrease_readers() {

  jint result = Atomic::add(-1, &_active_readers);

  assert(result >= 0, "Ensure we have consistent state");

  return result;

}

void LogOutputList::wait_until_no_readers() const {

  OrderAccess::storeload();

  while (_active_readers != 0) {

    // Busy wait

  }

}

void LogOutputList::set_output_level(LogOutput* output, LogLevelType level) {

  LogOutputNode* node = find(output);

  if (level == LogLevel::Off && node != NULL) {

    remove_output(node);

  } else if (level != LogLevel::Off && node == NULL) {

    add_output(output, level);

  } else if (node != NULL) {

    update_output_level(node, level);

  }

}

LogOutputList::LogOutputNode* LogOutputList::find(const LogOutput* output) const {

  for (LogOutputNode* node = _level_start[LogLevel::Last]; node != NULL; node = node->_next) {

    if (output == node->_value) {

      return node;

    }

  }

  return NULL;

}

void LogOutputList::remove_output(LogOutputList::LogOutputNode* node) {

  assert(node != NULL, "Node must be non-null");

  // Remove node from _level_start first

  bool found = false;

  for (uint level = LogLevel::First; level < LogLevel::Count; level++) {

    if (_level_start[level] == node) {

      found = true;

      _level_start[level] = node->_next;

    }

  }

  // Now remove it from the linked list

  for (LogOutputNode* cur = _level_start[LogLevel::Last]; cur != NULL; cur = cur->_next) {

    if (cur->_next == node) {

      found = true;

      cur->_next = node->_next;

      break;

    }

  }

  assert(found, "Node to be removed should always be found");

  wait_until_no_readers();

  delete node;

}

void LogOutputList::add_output(LogOutput* output, LogLevelType level) {

  LogOutputNode* node = new LogOutputNode();

  node->_value = output;

  node->_level = level;

  // Set the next pointer to the first node of a lower level

  for (node->_next = _level_start[level];

       node->_next != NULL && node->_next->_level == level;

       node->_next = node->_next->_next) {

  }

  // Update the _level_start index

  for (int l = LogLevel::Last; l >= level; l--) {

    if (_level_start[l] == NULL || _level_start[l]->_level < level) {

      _level_start[l] = node;

    }

  }

  // Add the node the list

  for (LogOutputNode* cur = _level_start[LogLevel::Last]; cur != NULL; cur = cur->_next) {

    if (cur != node && cur->_next == node->_next) {

      cur->_next = node;

      break;

    }

  }

}

void LogOutputList::update_output_level(LogOutputList::LogOutputNode* node, LogLevelType level) {

  add_output(node->_value, level);

  wait_until_no_readers();

  remove_output(node);

}