libopkg/active_list.c

   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
  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  */
  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
  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
  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
  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
 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
 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
 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
 135 void active_list_head_delete(struct active_list *head)
 136 {
 137         active_list_clear(head);
 138         free(head);
 139 }