sci_base_subject.c revision 331722 
1/*-
2 * This file is provided under a dual BSD/GPLv2 license.  When using or
3 * redistributing this file, you may do so under either license.
4 *
5 * GPL LICENSE SUMMARY
6 *
7 * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of version 2 of the GNU General Public License as
11 * published by the Free Software Foundation.
12 *
13 * This program is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16 * General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
21 * The full GNU General Public License is included in this distribution
22 * in the file called LICENSE.GPL.
23 *
24 * BSD LICENSE
25 *
26 * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
27 * All rights reserved.
28 *
29 * Redistribution and use in source and binary forms, with or without
30 * modification, are permitted provided that the following conditions
31 * are met:
32 *
33 *   * Redistributions of source code must retain the above copyright
34 *     notice, this list of conditions and the following disclaimer.
35 *   * Redistributions in binary form must reproduce the above copyright
36 *     notice, this list of conditions and the following disclaimer in
37 *     the documentation and/or other materials provided with the
38 *     distribution.
39 *
40 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
41 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
42 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
43 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
44 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
45 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
46 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
47 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
48 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
49 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
50 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
51 */
52
53#include <sys/cdefs.h>
54__FBSDID("$FreeBSD: stable/11/sys/dev/isci/scil/sci_base_subject.c 331722 2018-03-29 02:50:57Z eadler $");
55
56/**
57 * @file
58 *
59 * @brief This file contains the base subject method implementations and
60 *        any constants or structures private to the base subject object.
61 *        A subject is a participant in the observer design pattern.  A
62 *        subject represents the object being observed.
63 */
64
65#include <dev/isci/scil/sci_types.h>
66#include <dev/isci/scil/sci_base_subject.h>
67#include <dev/isci/scil/sci_base_observer.h>
68
69#if defined(SCI_LOGGING)
70
71//******************************************************************************
72//* P R O T E C T E D    M E T H O D S
73//******************************************************************************
74
75void sci_base_subject_construct(
76   SCI_BASE_SUBJECT_T *this_subject
77)
78{
79   this_subject->observer_list = NULL;
80}
81
82// ---------------------------------------------------------------------------
83
84void sci_base_subject_notify(
85   SCI_BASE_SUBJECT_T *this_subject
86)
87{
88   SCI_BASE_OBSERVER_T *this_observer = this_subject->observer_list;
89
90   while (this_observer != NULL)
91   {
92      sci_base_observer_update(this_observer, this_subject);
93
94      this_observer = this_observer->next;
95   }
96}
97
98// ---------------------------------------------------------------------------
99
100void sci_base_subject_attach_observer(
101   SCI_BASE_SUBJECT_T   *this_subject,
102   SCI_BASE_OBSERVER_T  *observer
103)
104{
105   observer->next = this_subject->observer_list;
106
107   this_subject->observer_list = observer;
108}
109
110// ---------------------------------------------------------------------------
111
112void sci_base_subject_detach_observer(
113   SCI_BASE_SUBJECT_T   *this_subject,
114   SCI_BASE_OBSERVER_T  *observer
115)
116{
117   SCI_BASE_OBSERVER_T *current_observer = this_subject->observer_list;
118   SCI_BASE_OBSERVER_T *previous_observer = NULL;
119
120   // Search list for the item to remove
121   while (
122              current_observer != NULL
123           && current_observer != observer
124         )
125   {
126      previous_observer = current_observer;
127      current_observer = current_observer->next;
128   }
129
130   // Was this observer in the list?
131   if (current_observer == observer)
132   {
133      if (previous_observer != NULL)
134      {
135         // Remove from middle or end of list
136         previous_observer->next = observer->next;
137      }
138      else
139      {
140         // Remove from the front of the list
141         this_subject->observer_list = observer->next;
142      }
143
144      // protect the list so people dont follow bad pointers
145      observer->next = NULL;
146   }
147}
148
149#endif // defined(SCI_LOGGING)
150