cache-node.c

/*
 * cache-node.c
 *
 * Used in diskomd.
 */

#include <stdio.h>
#include <kom-types.h>
#include "exp.h"
#include "cache-node.h"
#include <server/smalloc.h>
#include "lyskomd.h"

EXPORT const Cache_node EMPTY_CACHE_NODE =
    ((Cache_node){{ 0, 0, 0}, NULL, NULL, 0, 0, 0, 0, NULL, NULL, 0});

EXPORT const Cache_node_block EMPTY_CACHE_NODE_BLOCK =
    ((Cache_node_block){ 0, NULL, NULL});

EXPORT const Cache_node_mcb EMPTY_CACHE_NODE_MCB =
    ((Cache_node_mcb){ 0, NULL, 0, 0, NULL, NULL, 0, NULL });


EXPORT  void
unlink_lru(Cache_node *node,
	   Cache_node **lru,
	   Cache_node **mru)
{
    Cache_node *link;
    
    link = node->next;

    if ( node->next != NULL )
	node->next->prev = node->prev;
    else if (*lru == node)
	*lru = node->prev;

    if ( node->prev != NULL )
	node->prev->next = link;
    else if (*mru == node)
	*mru = link;

    node->next = NULL;
    node->prev = NULL;
}

EXPORT  void
insert_mru(Cache_node *node,
	   Cache_node **lru,
	   Cache_node **mru)
{
    node->prev = NULL;
    node->next = *mru;
    *mru = node;
    if ( *lru == NULL )
	*lru = node;

    if ( node->next != NULL )
	node->next->prev = node;
}

static Cache_node_mcb *
alloc_cache_node_mcb(void)
{
    Cache_node_mcb *t;

    t = smalloc(sizeof(Cache_node_mcb));
    *t = EMPTY_CACHE_NODE_MCB;
    return t;
}