freebsd-dev/sys/dev/isci/scil/sci_base_subject.c

/*-
 * SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0
 *
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * GPL LICENSE SUMMARY
 *
 * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 * The full GNU General Public License is included in this distribution
 * in the file called LICENSE.GPL.
 *
 * BSD LICENSE
 *
 * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in
 *     the documentation and/or other materials provided with the
 *     distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

/**
 * @file
 *
 * @brief This file contains the base subject method implementations and
 *        any constants or structures private to the base subject object.
 *        A subject is a participant in the observer design pattern.  A
 *        subject represents the object being observed.
 */

#include <dev/isci/scil/sci_types.h>
#include <dev/isci/scil/sci_base_subject.h>
#include <dev/isci/scil/sci_base_observer.h>

#if defined(SCI_LOGGING)

//******************************************************************************
//* P R O T E C T E D    M E T H O D S
//******************************************************************************

void sci_base_subject_construct(
   SCI_BASE_SUBJECT_T *this_subject
)
{
   this_subject->observer_list = NULL;
}

// ---------------------------------------------------------------------------

void sci_base_subject_notify(
   SCI_BASE_SUBJECT_T *this_subject
)
{
   SCI_BASE_OBSERVER_T *this_observer = this_subject->observer_list;

   while (this_observer != NULL)
   {
      sci_base_observer_update(this_observer, this_subject);

      this_observer = this_observer->next;
   }
}

// ---------------------------------------------------------------------------

void sci_base_subject_attach_observer(
   SCI_BASE_SUBJECT_T   *this_subject,
   SCI_BASE_OBSERVER_T  *observer
)
{
   observer->next = this_subject->observer_list;

   this_subject->observer_list = observer;
}

// ---------------------------------------------------------------------------

void sci_base_subject_detach_observer(
   SCI_BASE_SUBJECT_T   *this_subject,
   SCI_BASE_OBSERVER_T  *observer
)
{
   SCI_BASE_OBSERVER_T *current_observer = this_subject->observer_list;
   SCI_BASE_OBSERVER_T *previous_observer = NULL;

   // Search list for the item to remove
   while (
              current_observer != NULL
           && current_observer != observer
         )
   {
      previous_observer = current_observer;
      current_observer = current_observer->next;
   }

   // Was this observer in the list?
   if (current_observer == observer)
   {
      if (previous_observer != NULL)
      {
         // Remove from middle or end of list
         previous_observer->next = observer->next;
      }
      else
      {
         // Remove from the front of the list
         this_subject->observer_list = observer->next;
      }

      // protect the list so people dont follow bad pointers
      observer->next = NULL;
   }
}

#endif // defined(SCI_LOGGING)