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->depended = NULL;
  27 }
  28
  29 /**
  30  */
  31 struct active_list * active_list_next(struct active_list *head, struct active_list *ptr) {
  32     struct active_list *next=NULL;
  33     if ( !head ) {
  34         fprintf(stderr, "active_list_next head = %p, ptr = %p invalid value!!\n", head, ptr);
  35         return NULL;
  36     }
  37     if ( !ptr )
  38         ptr = head;
  39     next = list_entry(ptr->node.next, struct active_list, node);
  40     if ( next == head ) {
  41         return NULL;
  42     }
  43     if ( ptr->depended && &ptr->depended->depend == ptr->node.next ) {
  44         return ptr->depended;
  45     }
  46     while ( next->depend.next != &next->depend ) {
  47         next = list_entry(next->depend.next, struct active_list, node);
  48     }
  49     return next;
  50 }
  51
  52
  53 struct active_list * active_list_prev(struct active_list *head, struct active_list *ptr) {
  54     struct active_list *prev=NULL;
  55     if ( !head ) {
  56         fprintf(stderr, "active_list_prev head = %p, ptr = %p invalid value!!\n", head, ptr);
  57         return NULL;
  58     }
  59     if ( !ptr )
  60         ptr = head;
  61     if ( ptr->depend.prev != &ptr->depend ) {
  62         prev = list_entry(ptr->depend.prev, struct active_list, node);
  63         return prev;
  64     }
  65     if ( ptr->depended  && ptr->depended != head && &ptr->depended->depend == ptr->node.prev ) {
  66         prev = list_entry(ptr->depended->node.prev, struct active_list, node);
  67     } else
  68         prev = list_entry(ptr->node.prev, struct active_list, node);
  69     if ( prev == head )
  70         return NULL;
  71     return prev;
  72 }
  73
  74 static void list_head_clear (struct list_head *head) {
  75     struct active_list *next;
  76     struct list_head *n, *ptr;
  77     if (!head)
  78         return;
  79     list_for_each_safe(ptr, n , head) {
  80         next = list_entry(ptr, struct active_list, node);
  81         if (next->depend.next != &next->depend) {
  82             list_head_clear(&next->depend);
  83         }
  84         active_list_init(next);
  85     }
  86 }
  87 void active_list_clear(struct active_list *head) {
  88     list_head_clear(&head->node);
  89     if (head->depend.next != &head->depend) {
  90         list_head_clear(&head->depend);
  91     }
  92     active_list_init(head);
  93 }
  94
  95 void active_list_add_depend(struct active_list *node, struct active_list *depend) {
  96     list_del_init(&depend->node);
  97     list_add_tail(&depend->node, &node->depend);
  98     depend->depended  = node;
  99 }
 100
 101 void active_list_add(struct active_list *head, struct active_list *node) {
 102     list_del_init(&node->node);
 103     list_add_tail(&node->node, &head->node);
 104     node->depended  = head;
 105 }