/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996, 1997, 1998, 1999
 *	Sleepycat Software.  All rights reserved.
 */
/*
 * Copyright (c) 1995, 1996
 *	The President and Fellows of Harvard University.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Margo Seltzer.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "db_config.h"

#ifndef lint
static const char sccsid[] = "@(#)db_dispatch.c	11.7 (Sleepycat) 9/9/99";
#endif /* not lint */

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>

#include <errno.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#endif

#include "db_int.h"
#include "db_page.h"
#include "db_dispatch.h"
#include "db_am.h"
#include "log_auto.h"
#include "txn.h"
#include "txn_auto.h"
#include "log.h"

/*
 * CDB___db_dispatch --
 *
 * This is the transaction dispatch function used by the db access methods.
 * It is designed to handle the record format used by all the access
 * methods (the one automatically generated by the db_{h,log,read}.sh
 * scripts in the tools directory).  An application using a different
 * recovery paradigm will supply a different dispatch function to txn_open.
 *
 * PUBLIC: int CDB___db_dispatch __P((DB_ENV *, DBT *, DB_LSN *, int, void *));
 */
int
CDB___db_dispatch(dbenv, db, lsnp, redo, info)
	DB_ENV *dbenv;		/* The environment. */
	DBT *db;		/* The log record upon which to dispatch. */
	DB_LSN *lsnp;		/* The lsn of the record being dispatched. */
	int redo;		/* Redo this op (or undo it). */
	void *info;
{
	u_int32_t rectype, txnid;

	memcpy(&rectype, db->data, sizeof(rectype));
	memcpy(&txnid, (u_int8_t *)db->data + sizeof(rectype), sizeof(txnid));

	switch (redo) {
	case TXN_REDO:
	case TXN_UNDO:
		return ((dbenv->dtab[rectype])(dbenv, db, lsnp, redo, info));
	case TXN_OPENFILES:
		if (rectype < DB_txn_BEGIN )
			return ((dbenv->dtab[rectype])(dbenv,
			    db, lsnp, redo, info));
		break;
	case TXN_BACKWARD_ROLL:
		/*
		 * Running full recovery in the backward pass.  If we've
		 * seen this txnid before and added to it our commit list,
		 * then we do nothing during this pass.  If we've never
		 * seen it, then we call the appropriate recovery routine
		 * in "abort mode".
		 *
 		 * We need to always undo DB_db_noop records, so that we
 		 * properly handle any aborts before the file was closed.
  		 */
  		if (rectype == DB_log_register || rectype == DB_txn_ckp ||
		    rectype == DB_db_noop ||
		    (CDB___db_txnlist_find(info, txnid) == DB_NOTFOUND &&
		    txnid != 0))
			return ((dbenv->dtab[rectype])(dbenv,
			    db, lsnp, TXN_UNDO, info));
		break;
	case TXN_FORWARD_ROLL:
		/*
		 * In the forward pass, if we haven't seen the transaction,
		 * do nothing, else recovery it.
		 *
		 * We need to always redo DB_db_noop records, so that we
		 * properly handle any commits after the file was closed.
		 */
		if (rectype == DB_log_register || rectype == DB_txn_ckp ||
		    rectype == DB_db_noop ||
		    CDB___db_txnlist_find(info, txnid) != DB_NOTFOUND)
			return ((dbenv->dtab[rectype])(dbenv,
			    db, lsnp, TXN_REDO, info));
		break;
	default:
		abort();
	}
	return (0);
}

/*
 * CDB___db_add_recovery --
 *
 * PUBLIC: int CDB___db_add_recovery __P((DB_ENV *,
 * PUBLIC:    int (*)(DB_ENV *, DBT *, DB_LSN *, int, void *), u_int32_t));
 */
int
CDB___db_add_recovery(dbenv, func, ndx)
	DB_ENV *dbenv;
	int (*func) __P((DB_ENV *, DBT *, DB_LSN *, int, void *));
	u_int32_t ndx;
{
	u_int32_t i;
	int ret;

	/* Check if we have to grow the table. */
	if (ndx >= dbenv->dtab_size) {
		if ((ret = CDB___os_realloc(
		    (DB_user_BEGIN + dbenv->dtab_size) * sizeof(dbenv->dtab[0]),
		    NULL, &dbenv->dtab)) != 0)
			return (ret);
		for (i = dbenv->dtab_size,
		    dbenv->dtab_size += DB_user_BEGIN;
		    i < dbenv->dtab_size; ++i)
			dbenv->dtab[i] = NULL;
	}

	dbenv->dtab[ndx] = func;
	return (0);
}

/*
 * CDB___db_txnlist_init --
 *	Initialize transaction linked list.
 *
 * PUBLIC: int CDB___db_txnlist_init __P((void *));
 */
int
CDB___db_txnlist_init(retp)
	void *retp;
{
	DB_TXNHEAD *headp;
	int ret;

	if ((ret = CDB___os_malloc(sizeof(DB_TXNHEAD), NULL, &headp)) != 0)
		return (ret);

	LIST_INIT(&headp->head);
	headp->maxid = 0;
	headp->generation = 1;

	*(void **)retp = headp;
	return (0);
}

/*
 * CDB___db_txnlist_add --
 *	Add an element to our transaction linked list.
 *
 * PUBLIC: int CDB___db_txnlist_add __P((void *, u_int32_t));
 */
int
CDB___db_txnlist_add(listp, txnid)
	void *listp;
	u_int32_t txnid;
{
	DB_TXNHEAD *hp;
	DB_TXNLIST *elp;
	int ret;

	if ((ret = CDB___os_malloc(sizeof(DB_TXNLIST), NULL, &elp)) != 0)
		return (ret);

	hp = (DB_TXNHEAD *)listp;
	LIST_INSERT_HEAD(&hp->head, elp, links);

	elp->type = TXNLIST_TXNID;
	elp->u.t.txnid = txnid;
	if (txnid > hp->maxid)
		hp->maxid = txnid;
	elp->u.t.generation = hp->generation;

	return (0);
}

/* CDB___db_txnlist_close --
 *
 * 	Call this when we close a file.  It allows us to reconcile whether
 * we have done any operations on this file with whether the file appears
 * to have been deleted.  If you never do any operations on a file, then
 * we assume it's OK to appear deleted.
 *
 * PUBLIC: int CDB___db_txnlist_close __P((void *, u_int32_t, u_int32_t));
 */

int
CDB___db_txnlist_close(listp, lid, count)
	void *listp;
	u_int32_t lid;
	u_int32_t count;
{
	DB_TXNHEAD *hp;
	DB_TXNLIST *p;

	hp = (DB_TXNHEAD *)listp;
	for (p = hp->head.lh_first; p != NULL; p = p->links.le_next) {
		if (p->type == TXNLIST_DELETE)
			if (lid == p->u.d.fileid &&
			    !F_ISSET(&p->u.d, TXNLIST_FLAG_CLOSED)) {
				p->u.d.count += count;
				return (0);
			}
	}

	return (0);
}

/*
 * CDB___db_txnlist_delete --
 *
 *	Record that a file was missing or deleted.  If the deleted
 * flag is set, then we've encountered a delete of a file, else we've
 * just encountered a file that is missing.  The lid is the log fileid
 * and is only meaningful if deleted is not equal to 0.
 *
 * PUBLIC: int CDB___db_txnlist_delete __P((void *, char *, u_int32_t, int));
 */
int
CDB___db_txnlist_delete(listp, name, lid, deleted)
	void *listp;
	char *name;
	u_int32_t lid;
	int deleted;
{
	DB_TXNHEAD *hp;
	DB_TXNLIST *p;
	int ret;

	hp = (DB_TXNHEAD *)listp;
	for (p = hp->head.lh_first; p != NULL; p = p->links.le_next) {
		if (p->type == TXNLIST_DELETE)
			if (strcmp(name, p->u.d.fname) == 0) {
				if (deleted)
					F_SET(&p->u.d, TXNLIST_FLAG_DELETED);
				else
					F_CLR(&p->u.d, TXNLIST_FLAG_CLOSED);
				return (0);
			}
	}

	/* Need to add it. */
	if ((ret = CDB___os_malloc(sizeof(DB_TXNLIST), NULL, &p)) != 0)
		return (ret);
	LIST_INSERT_HEAD(&hp->head, p, links);

	p->type = TXNLIST_DELETE;
	p->u.d.flags = 0;
	if (deleted)
		F_SET(&p->u.d, TXNLIST_FLAG_DELETED);
	p->u.d.fileid = lid;
	p->u.d.count = 0;
	ret = CDB___os_strdup(name, &p->u.d.fname);

	return (ret);
}

/*
 * CDB___db_txnlist_end --
 *	Discard transaction linked list. Print out any error messages
 * for deleted files.
 *
 * PUBLIC: void CDB___db_txnlist_end __P((DB_ENV *, void *));
 */
void
CDB___db_txnlist_end(dbenv, listp)
	DB_ENV *dbenv;
	void *listp;
{
	DB_TXNHEAD *hp;
	DB_TXNLIST *p;
	DB_LOG *lp;

	hp = (DB_TXNHEAD *)listp;
	lp = (DB_LOG *)dbenv->lg_handle;
	while (hp != NULL &&
	    (p = LIST_FIRST(&hp->head)) != LIST_END(&hp->head)) {
		LIST_REMOVE(p, links);
		if (p->type == TXNLIST_DELETE) {
			/*
			 * If we have a file that is not deleted and has
			 * some operations, we flag the warning.  Since
			 * the file could still be open, we need to check
			 * the actual log table as well.
			 */
			if ((!F_ISSET(&p->u.d, TXNLIST_FLAG_DELETED) &&
			    p->u.d.count != 0) ||
			    (!F_ISSET(&p->u.d, TXNLIST_FLAG_CLOSED) &&
			    p->u.d.fileid < lp->dbentry_cnt &&
			    lp->dbentry[p->u.d.fileid].count != 0))
				CDB___db_err(dbenv, "warning: %s: %s",
				    p->u.d.fname, CDB_db_strerror(ENOENT));
			CDB___os_freestr(p->u.d.fname);
		}
		CDB___os_free(p, sizeof(DB_TXNLIST));
	}
	CDB___os_free(listp, sizeof(DB_TXNHEAD));
}

/*
 * CDB___db_txnlist_find --
 *	Checks to see if a txnid with the current generation is in the
 *	txnid list.
 *
 * PUBLIC: int CDB___db_txnlist_find __P((void *, u_int32_t));
 */
int
CDB___db_txnlist_find(listp, txnid)
	void *listp;
	u_int32_t txnid;
{
	DB_TXNHEAD *hp;
	DB_TXNLIST *p;

	if ((hp = (DB_TXNHEAD *)listp) == NULL)
		return (DB_NOTFOUND);

	for (p = hp->head.lh_first; p != NULL; p = p->links.le_next) {
		if (p->type != TXNLIST_TXNID)
			continue;
		if (p->u.t.txnid == txnid &&
		    hp->generation == p->u.t.generation)
			return (0);
	}

	return (DB_NOTFOUND);
}

/*
 * CDB___db_txnlist_gen --
 *	Change the current generation number.
 *
 * PUBLIC: void CDB___db_txnlist_gen __P((void *, int));
 */
void
CDB___db_txnlist_gen(listp, incr)
	void *listp;
	int incr;
{
	DB_TXNHEAD *hp;

	/*
	 * During recovery generation numbers keep track of how many "restart"
	 * checkpoints we've seen.  Restart checkpoints occur whenever we take
	 * a checkpoint and there are no outstanding transactions.  When that
	 * happens, we can reset transaction IDs back to 1.  It always happens
	 * at recovery and it prevents us from exhausting the transaction IDs
	 * name space.
	 */
	hp = (DB_TXNHEAD *)listp;
	hp->generation += incr;
}

#ifdef DEBUG
/*
 * CDB___db_txnlist_print --
 *	Print out the transaction list.
 *
 * PUBLIC: void CDB___db_txnlist_print __P((void *));
 */
void
CDB___db_txnlist_print(listp)
	void *listp;
{
	DB_TXNHEAD *hp;
	DB_TXNLIST *p;

	hp = (DB_TXNHEAD *)listp;

	printf("Maxid: %lu Generation: %lu\n",
	    (u_long)hp->maxid, (u_long)hp->generation);
	for (p = hp->head.lh_first; p != NULL; p = p->links.le_next) {
		switch (p->type) {
		case TXNLIST_TXNID:
			printf("TXNID: %lu(%lu)\n",
			    (u_long)p->u.t.txnid, (u_long)p->u.t.generation);
			break;
		case TXNLIST_DELETE:
			printf("FILE: %s id=%d ops=%d %s %s\n",
			    p->u.d.fname, p->u.d.fileid, p->u.d.count,
			    F_ISSET(&p->u.d, TXNLIST_FLAG_DELETED) ?
			    "(deleted)" : "(missing)",
			    F_ISSET(&p->u.d, TXNLIST_FLAG_CLOSED) ?
			    "(closed)" : "(open)");

			break;
		default:
			printf("Unrecognized type: %d\n", p->type);
			break;
		}
	}
}
#endif