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/*
* UCW Library -- Configuration files: journaling
*
* (c) 2001--2006 Robert Spalek <robert@ucw.cz>
* (c) 2003--2012 Martin Mares <mj@ucw.cz>
*
* This software may be freely distributed and used according to the terms
* of the GNU Lesser General Public License.
*/
#include <ucw/lib.h>
#include <ucw/conf.h>
#include <ucw/getopt.h>
#include <ucw/conf-internal.h>
#include <ucw/mempool.h>
#include <string.h>
struct old_pools {
struct old_pools *prev;
struct mempool *pool;
}; // link-list of older cf_pool's
struct cf_journal_item {
struct cf_journal_item *prev;
byte *ptr;
uint len;
byte copy[0];
};
void
cf_set_journalling(int enable)
{
struct cf_context *cc = cf_get_context();
ASSERT(!cc->journal);
cc->enable_journal = enable;
}
void
cf_journal_block(void *ptr, uint len)
{
struct cf_context *cc = cf_get_context();
if (!cc->enable_journal)
return;
struct cf_journal_item *ji = cf_malloc(sizeof(struct cf_journal_item) + len);
ji->prev = cc->journal;
ji->ptr = ptr;
ji->len = len;
memcpy(ji->copy, ptr, len);
cc->journal = ji;
}
void
cf_journal_swap(void)
// swaps the contents of the memory and the journal, and reverses the list
{
struct cf_context *cc = cf_get_context();
struct cf_journal_item *curr, *prev, *next;
for (next=NULL, curr=cc->journal; curr; next=curr, curr=prev)
{
prev = curr->prev;
curr->prev = next;
for (uint i=0; i<curr->len; i++)
{
byte x = curr->copy[i];
curr->copy[i] = curr->ptr[i];
curr->ptr[i] = x;
}
}
cc->journal = next;
}
struct cf_journal_item *
cf_journal_new_transaction(uint new_pool)
{
struct cf_context *cc = cf_get_context();
if (new_pool)
cc->pool = mp_new(1<<10);
struct cf_journal_item *oldj = cc->journal;
cc->journal = NULL;
return oldj;
}
void
cf_journal_commit_transaction(uint new_pool, struct cf_journal_item *oldj)
{
struct cf_context *cc = cf_get_context();
if (new_pool)
{
struct old_pools *p = cf_malloc(sizeof(struct old_pools));
p->prev = cc->pools;
p->pool = cc->pool;
cc->pools = p;
}
if (oldj)
{
struct cf_journal_item **j = &cc->journal;
while (*j)
j = &(*j)->prev;
*j = oldj;
}
}
void
cf_journal_rollback_transaction(uint new_pool, struct cf_journal_item *oldj)
{
struct cf_context *cc = cf_get_context();
if (!cc->enable_journal)
return;
cf_journal_swap();
cc->journal = oldj;
if (new_pool)
{
mp_delete(cc->pool);
cc->pool = cc->pools ? cc->pools->pool : NULL;
}
}
void
cf_journal_delete(void)
{
struct cf_context *cc = cf_get_context();
for (struct old_pools *p=cc->pools; p; p=cc->pools)
{
cc->pools = p->prev;
mp_delete(p->pool);
}
}