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 #include <string.h>
  22 #include <stdlib.h>
  23
  24 #include "libbb/libbb.h"
  25
  26 void active_list_init(struct active_list *ptr) {
  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, struct active_list *ptr) {
  35     struct active_list *next=NULL;
  36     if ( !head ) {
  37         opkg_msg(ERROR, "Internal error: head=%p, ptr=%p\n", head, ptr);
  38         return NULL;
  39     }
  40     if ( !ptr )
  41         ptr = head;
  42     next = list_entry(ptr->node.next, struct active_list, node);
  43     if ( next == head ) {
  44         return NULL;
  45     }
  46     if ( ptr->depended && &ptr->depended->depend == ptr->node.next ) {
  47         return ptr->depended;
  48     }
  49     while ( next->depend.next != &next->depend ) {
  50         next = list_entry(next->depend.next, struct active_list, node);
  51     }
  52     return next;
  53 }
  54
  55
  56 struct active_list * active_list_prev(struct active_list *head, struct active_list *ptr) {
  57     struct active_list *prev=NULL;
  58     if ( !head ) {
  59         opkg_msg(ERROR, "Internal error: head=%p, ptr=%p\n", head, ptr);
  60         return NULL;
  61     }
  62     if ( !ptr )
  63         ptr = head;
  64     if ( ptr->depend.prev != &ptr->depend ) {
  65         prev = list_entry(ptr->depend.prev, struct active_list, node);
  66         return prev;
  67     }
  68     if ( ptr->depended  && ptr->depended != head && &ptr->depended->depend == ptr->node.prev ) {
  69         prev = list_entry(ptr->depended->node.prev, struct active_list, node);
  70     } else
  71         prev = list_entry(ptr->node.prev, struct active_list, node);
  72     if ( prev == head )
  73         return NULL;
  74     return prev;
  75 }
  76
  77
  78 struct active_list *active_list_move_node(struct active_list *old_head, struct active_list *new_head, struct active_list *node) {
  79     struct active_list *prev;
  80     if (!old_head || !new_head || !node)
  81         return NULL;
  82     if (old_head == new_head)
  83         return node;
  84     prev = active_list_prev(old_head, node);
  85     active_list_add(new_head, node);
  86     return prev;
  87 }
  88
  89 static void list_head_clear (struct list_head *head) {
  90     struct active_list *next;
  91     struct list_head *n, *ptr;
  92     if (!head)
  93         return;
  94     list_for_each_safe(ptr, n , head) {
  95         next = list_entry(ptr, struct active_list, node);
  96         if (next->depend.next != &next->depend) {
  97             list_head_clear(&next->depend);
  98         }
  99         active_list_init(next);
 100     }
 101 }
 102 void active_list_clear(struct active_list *head) {
 103     list_head_clear(&head->node);
 104     if (head->depend.next != &head->depend) {
 105         list_head_clear(&head->depend);
 106     }
 107     active_list_init(head);
 108 }
 109
 110 void active_list_add_depend(struct active_list *node, struct active_list *depend) {
 111     list_del_init(&depend->node);
 112     list_add_tail(&depend->node, &node->depend);
 113     depend->depended  = node;
 114 }
 115
 116 void active_list_add(struct active_list *head, struct active_list *node) {
 117     list_del_init(&node->node);
 118     list_add_tail(&node->node, &head->node);
 119     node->depended  = head;
 120 }
 121
 122 struct active_list * active_list_head_new(void) {
 123     struct active_list * head = xcalloc(1, sizeof(struct active_list));
 124     active_list_init(head);
 125     return head;
 126 }
 127
 128 void active_list_head_delete(struct active_list *head) {
 129     active_list_clear(head);
 130     free(head);
 131 }
 132
 133 /*
 134  *  Using insert sort.
 135  *  Note. the list should not be large, or it will be very inefficient.
 136  *
 137  */
 138 struct active_list * active_list_sort(struct active_list *head, int (*compare)(const void *, const void *)) {
 139     struct active_list tmphead;
 140     struct active_list *node, *ptr;
 141     if ( !head )
 142         return NULL;
 143     active_list_init(&tmphead);
 144     for (node = active_list_next(head, NULL); node; node = active_list_next(head, NULL)) {
 145         if (tmphead.node.next == &tmphead.node) {
 146             active_list_move_node(head, &tmphead, node);
 147         } else {
 148             for (ptr = active_list_next(&tmphead, NULL); ptr; ptr=active_list_next(&tmphead, ptr)) {
 149                 if (compare(ptr, node) <= 0) {
 150                     break;
 151                 }
 152             }
 153             if (!ptr) {
 154                 active_list_move_node(head, &tmphead, node);
 155             } else {
 156                 active_list_move_node(head, ptr, node);
 157             }
 158         }
 159         node->depended = &tmphead;
 160     }
 161     for (ptr = active_list_prev(&tmphead, NULL); ptr; ptr=active_list_prev(&tmphead, NULL)) {
 162         active_list_move_node(&tmphead, head, ptr);
 163     }
 164     return head;
 165 }