sci_base_subject.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0
3 *
4 * This file is provided under a dual BSD/GPLv2 license.  When using or
5 * redistributing this file, you may do so under either license.
6 *
7 * GPL LICENSE SUMMARY
8 *
9 * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of version 2 of the GNU General Public License as
13 * published by the Free Software Foundation.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
23 * The full GNU General Public License is included in this distribution
24 * in the file called LICENSE.GPL.
25 *
26 * BSD LICENSE
27 *
28 * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
29 * All rights reserved.
30 *
31 * Redistribution and use in source and binary forms, with or without
32 * modification, are permitted provided that the following conditions
33 * are met:
34 *
35 *   * Redistributions of source code must retain the above copyright
36 *     notice, this list of conditions and the following disclaimer.
37 *   * Redistributions in binary form must reproduce the above copyright
38 *     notice, this list of conditions and the following disclaimer in
39 *     the documentation and/or other materials provided with the
40 *     distribution.
41 *
42 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
43 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
44 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
45 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
46 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
47 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
48 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
49 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
50 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
51 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
52 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
53 */
54
55#include <sys/cdefs.h>
56__FBSDID("$FreeBSD: stable/11/sys/dev/isci/scil/sci_base_subject.c 330897 2018-03-14 03:19:51Z eadler $");
57
58/**
59 * @file
60 *
61 * @brief This file contains the base subject method implementations and
62 *        any constants or structures private to the base subject object.
63 *        A subject is a participant in the observer design pattern.  A
64 *        subject represents the object being observed.
65 */
66
67#include <dev/isci/scil/sci_types.h>
68#include <dev/isci/scil/sci_base_subject.h>
69#include <dev/isci/scil/sci_base_observer.h>
70
71#if defined(SCI_LOGGING)
72
73//******************************************************************************
74//* P R O T E C T E D    M E T H O D S
75//******************************************************************************
76
77void sci_base_subject_construct(
78   SCI_BASE_SUBJECT_T *this_subject
79)
80{
81   this_subject->observer_list = NULL;
82}
83
84// ---------------------------------------------------------------------------
85
86void sci_base_subject_notify(
87   SCI_BASE_SUBJECT_T *this_subject
88)
89{
90   SCI_BASE_OBSERVER_T *this_observer = this_subject->observer_list;
91
92   while (this_observer != NULL)
93   {
94      sci_base_observer_update(this_observer, this_subject);
95
96      this_observer = this_observer->next;
97   }
98}
99
100// ---------------------------------------------------------------------------
101
102void sci_base_subject_attach_observer(
103   SCI_BASE_SUBJECT_T   *this_subject,
104   SCI_BASE_OBSERVER_T  *observer
105)
106{
107   observer->next = this_subject->observer_list;
108
109   this_subject->observer_list = observer;
110}
111
112// ---------------------------------------------------------------------------
113
114void sci_base_subject_detach_observer(
115   SCI_BASE_SUBJECT_T   *this_subject,
116   SCI_BASE_OBSERVER_T  *observer
117)
118{
119   SCI_BASE_OBSERVER_T *current_observer = this_subject->observer_list;
120   SCI_BASE_OBSERVER_T *previous_observer = NULL;
121
122   // Search list for the item to remove
123   while (
124              current_observer != NULL
125           && current_observer != observer
126         )
127   {
128      previous_observer = current_observer;
129      current_observer = current_observer->next;
130   }
131
132   // Was this observer in the list?
133   if (current_observer == observer)
134   {
135      if (previous_observer != NULL)
136      {
137         // Remove from middle or end of list
138         previous_observer->next = observer->next;
139      }
140      else
141      {
142         // Remove from the front of the list
143         this_subject->observer_list = observer->next;
144      }
145
146      // protect the list so people dont follow bad pointers
147      observer->next = NULL;
148   }
149}
150
151#endif // defined(SCI_LOGGING)
152