# include	"AA_liba.h"

static int	AA_2_TA;

AAlock(d, rel, mod)
register DESCXX		*d;
register char		*rel;
register int		mod;
{
# ifdef AMX_TRACE
	AAtTfp(14, 0,
# ifdef MSDOS
		"use\t\t`%.10s' (%d) mod %d\n",
# else
		"use\t\t`%.14s' (%d) mod %d\n",
# endif
		rel, d->xx_locks, mod);
# endif
	errno = 0;

	if (!d)

	if (AA_NOLOCKS)
		return;

	if (AA_LOCKS)
		AAerror(107, "TA-begin");

	if (mod < 0)
	{
		if (AA_2_TA)
			goto concur;
		mod = -mod;
		AA_2_TA++;
	}
	else if (!AA_2_TA)
	{
concur:
		AAerror(107, "second TA");
	}

	do AArel_lock(d, mod); while (d = d->xx_index);
}


static	AArel_lock(d, mod)
register DESCXX		*d;
register int		mod;
{
# ifdef AMX_TRACE
	AAtTfp(31, 0,
# ifdef MSDOS
		"lock\t\t`%.10s' (%d) mod %d\n",
# else
		"lock\t\t`%.14s' (%d) mod %d\n",
# endif
		d->xx_desc.reldum.relid, d->xx_locks, mod);
# endif
	AA = errno = 0;

	if (d->xx_ta)
		AAerror(17, d->xx_desc.reldum.relid);

	if ((d->xx_excl = mod) == M_EXCL)
	{
		/* restore relation of descriptor d to read/write mode */
		d->xx_desc.relopn = RELWOPEN(d->xx_desc.relfp);
	}

	if (AA_TA)
	{
		d->xx_ta = AA_TA->xx_ta;
		AA_TA->xx_ta = d;
	}
	else
		d->xx_ta = d;
	AA_TA = d->xx_ta;

	do
	{
# ifdef AMX_TRACE
		AAtTfp(31, 1,
# ifdef MSDOS
			".... rtn (%d)\t`%.10s'\n",
# else
			".... rtn (%d)\t`%.14s'\n",
# endif
			d->xx_excl, d->xx_desc.reldum.relid);
# endif
		if (AAsetrll(A_RTN, d->xx_desc.reltid, d->xx_excl) < 0)
		{
			/* the lock request fails */
			AAunlock(0);
			/* wait on problem lock */
# ifdef AMX_TRACE
			AAtTfp(31, 2,
# ifdef MSDOS
				".... slp (%d)\t`%.10s'\n",
# else
				".... slp (%d)\t`%.14s'\n",
# endif
				d->xx_excl, d->xx_desc.reldum.relid);
# endif
			if (AAsetrll(A_SLP, d->xx_desc.reltid, AA = d->xx_excl) < 0)
				AAerror(17, d->xx_desc.reldum.relid);
			AA_TA = d;
		}
		d->xx_locks++;
	} while ((d = d->xx_ta) != AA_TA);
}


AAunlock(really)
register int	really;
{
	register DESCXX		*next;
	register DESCXX		*d;

# ifdef AMX_TRACE
	AAtTfp(15, 0, "commit\t\t(%d)\n", really);
# endif

	if (AA_NOLOCKS)
		return;

	if (!(next = AA_TA))
		AAerror(107, "TA-end");

	do
	{
		d = next;
		next = d->xx_ta;

		if (really)
		{
			d->xx_excl = 0;
			d->xx_ta = (DESCXX *) 0;
			AAnoclose(d);
			/* make believe relation is read only	*/
			/* for concurrency that means,		*/
			/* readed pages are not locked		*/
			if (!bitset(S_CATALOG, d->xx_desc.reldum.relstat))
				d->xx_desc.relopn = RELROPEN(d->xx_desc.relfp);
		}

		if ((AA = d->xx_locks) && AAunlrl(d->xx_desc.reltid) < 0)
			AAerror(18, d->xx_desc.reldum.relid);
		d->xx_locks = 0;
	} while (next != AA_TA);

	if (really)
	{
		AA_TA = (DESCXX *) 0;
		AA_2_TA = 0;
		AAdaemon = 0;
	}
}