xref: /freebsd/sys/dev/isci/scil/sci_base_subject.c (revision b1f9167f94059fd55c630891d359bcff987bd7eb)
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("$FreeBSD$");
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 
75 void sci_base_subject_construct(
76    SCI_BASE_SUBJECT_T *this_subject
77 )
78 {
79    this_subject->observer_list = NULL;
80 }
81 
82 // ---------------------------------------------------------------------------
83 
84 void 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 
100 void 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 
112 void 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