1 /* active_list.h - the opkg package management system
2
3 Tick Chen <tick@openmoko.com>
4
5 Copyright (C) 2008 Openmoko Inc.
6
7 This program is free software; you can redistribute it and/or
8 modify it under the terms of the GNU General Public License as
9 published by the Free Software Foundation; either version 2, or (at
10 your option) any later version.
11
12 This program is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 General Public License for more details.
16 */
17
18 #include "active_list.h"
19 #include <stdio.h>
20 #include <string.h>
21 #include <stdlib.h>
22
23 #include "libbb/libbb.h"
24
active_list_init(struct active_list * ptr)25 void active_list_init(struct active_list *ptr)
26 {
27 INIT_LIST_HEAD(&ptr->node);
28 INIT_LIST_HEAD(&ptr->depend);
29 ptr->depended = NULL;
30 }
31
32 /**
33 */
active_list_next(struct active_list * head,struct active_list * ptr)34 struct active_list *active_list_next(struct active_list *head,
35 struct active_list *ptr)
36 {
37 struct active_list *next = NULL;
38 if (!head) {
39 opkg_msg(ERROR, "Internal error: head=%p, ptr=%p\n", head, ptr);
40 return NULL;
41 }
42 if (!ptr)
43 ptr = head;
44 next = list_entry(ptr->node.next, struct active_list, node);
45 if (next == head) {
46 return NULL;
47 }
48 if (ptr->depended && &ptr->depended->depend == ptr->node.next) {
49 return ptr->depended;
50 }
51 while (next->depend.next != &next->depend) {
52 next = list_entry(next->depend.next, struct active_list, node);
53 }
54 return next;
55 }
56
active_list_prev(struct active_list * head,struct active_list * ptr)57 struct active_list *active_list_prev(struct active_list *head,
58 struct active_list *ptr)
59 {
60 struct active_list *prev = NULL;
61 if (!head) {
62 opkg_msg(ERROR, "Internal error: head=%p, ptr=%p\n", head, ptr);
63 return NULL;
64 }
65 if (!ptr)
66 ptr = head;
67 if (ptr->depend.prev != &ptr->depend) {
68 prev = list_entry(ptr->depend.prev, struct active_list, node);
69 return prev;
70 }
71 if (ptr->depended && ptr->depended != head
72 && &ptr->depended->depend == ptr->node.prev) {
73 prev =
74 list_entry(ptr->depended->node.prev, struct active_list,
75 node);
76 } else
77 prev = list_entry(ptr->node.prev, struct active_list, node);
78 if (prev == head)
79 return NULL;
80 return prev;
81 }
82
active_list_move_node(struct active_list * old_head,struct active_list * new_head,struct active_list * node)83 struct active_list *active_list_move_node(struct active_list *old_head,
84 struct active_list *new_head,
85 struct active_list *node)
86 {
87 struct active_list *prev;
88 if (!old_head || !new_head || !node)
89 return NULL;
90 if (old_head == new_head)
91 return node;
92 prev = active_list_prev(old_head, node);
93 active_list_add(new_head, node);
94 return prev;
95 }
96
list_head_clear(struct list_head * head)97 static void list_head_clear(struct list_head *head)
98 {
99 struct active_list *next;
100 struct list_head *n, *ptr;
101 if (!head)
102 return;
103 list_for_each_safe(ptr, n, head) {
104 next = list_entry(ptr, struct active_list, node);
105 if (next->depend.next != &next->depend) {
106 list_head_clear(&next->depend);
107 }
108 active_list_init(next);
109 }
110 }
111
active_list_clear(struct active_list * head)112 void active_list_clear(struct active_list *head)
113 {
114 list_head_clear(&head->node);
115 if (head->depend.next != &head->depend) {
116 list_head_clear(&head->depend);
117 }
118 active_list_init(head);
119 }
120
active_list_add(struct active_list * head,struct active_list * node)121 void active_list_add(struct active_list *head, struct active_list *node)
122 {
123 list_del_init(&node->node);
124 list_add_tail(&node->node, &head->node);
125 node->depended = head;
126 }
127
active_list_head_new(void)128 struct active_list *active_list_head_new(void)
129 {
130 struct active_list *head = xcalloc(1, sizeof(struct active_list));
131 active_list_init(head);
132 return head;
133 }
134
active_list_head_delete(struct active_list * head)135 void active_list_head_delete(struct active_list *head)
136 {
137 active_list_clear(head);
138 free(head);
139 }
140