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
  19 #include "active_list.h"
  20 #include <stdio.h>
  21
  22
  23 void active_list_init(struct active_list *ptr) {
  24     INIT_LIST_HEAD(&ptr->node);
  25     INIT_LIST_HEAD(&ptr->depend);
  26     ptr->walked=0;
  27     ptr->depended = NULL;
  28 }
  29
  30 /**
  31  */
  32 struct active_list * active_list_next(struct active_list *head, struct active_list *ptr) {
  33     struct active_list *next=NULL;
  34     if (!head || !ptr) {
  35         fprintf(stderr, "active_list_prev head = %p, ptr = %p invalid value!!\n", head, ptr);
  36         return NULL;
  37     }
  38     if (ptr == head) {
  39         head->walked = !head->walked;
  40         next = list_entry(ptr->node.next, struct active_list, node);
  41         if (next == head)
  42             return NULL;
  43         return active_list_next(head, next);
  44     }
  45     if (ptr->depend.next != &ptr->depend) {
  46         next = list_entry(ptr->depend.next, struct active_list, node);
  47         if (head->walked != next->walked) {
  48             ptr->walked = head->walked;
  49             return active_list_next(head, next);
  50         }
  51     }
  52     if (ptr->walked != head->walked) {
  53         ptr->walked = head->walked;
  54         return ptr;
  55     }
  56
  57     if (ptr->depended && ptr->node.next == &ptr->depended->depend ) {
  58         return ptr->depended;
  59     }
  60
  61     if (ptr->node.next != &head->node) {
  62         next = list_entry(ptr->node.next, struct active_list, node);
  63         return active_list_next(head, next);
  64     }
  65     return NULL;
  66 }
  67
  68
  69 void active_list_clear(struct active_list *head) {
  70 }
  71
  72 void active_list_add_depend(struct active_list *node, struct active_list *depend) {
  73     list_del_init(&depend->node);
  74     list_add_tail(&depend->node, &node->depend);
  75     depend->depended  = node;
  76 }
  77
  78 void active_list_add(struct active_list *head, struct active_list *node) {
  79     list_del_init(&node->node);
  80     list_add_tail(&node->node, &head->node);
  81 }