qam.c

这是国外的resip协议栈

		ret = DB_NOTFOUND;
		goto err;
	}

	pagep = cp->page;
	qp = QAM_GET_RECORD(dbp, pagep, cp->indx);

	if (DBC_LOGGING(dbc)) {
		if (((QUEUE *)dbp->q_internal)->page_ext == 0 ||
		    ((QUEUE *)dbp->q_internal)->re_len == 0) {
			if ((ret = __qam_del_log(dbp,
			    dbc->txn, &LSN(pagep), 0, &LSN(pagep),
			    pagep->pgno, cp->indx, cp->recno)) != 0)
				goto err;
		} else {
			data.size = ((QUEUE *)dbp->q_internal)->re_len;
			data.data = qp->data;
			if ((ret = __qam_delext_log(dbp,
			    dbc->txn, &LSN(pagep), 0, &LSN(pagep),
			    pagep->pgno, cp->indx, cp->recno, &data)) != 0)
				goto err;
		}
	}

	F_CLR(qp, QAM_VALID);

	if (cp->recno == first) {
		pg = ((QUEUE *)dbp->q_internal)->q_meta;
		if ((ret =
		    __db_lget(dbc, 0, pg,  DB_LOCK_WRITE, 0, &metalock)) != 0)
			goto err;
		ret = __qam_consume(dbc, meta, first);
		if ((t_ret = __LPUT(dbc, metalock)) != 0 && ret == 0)
			ret = t_ret;
	}

err:	if ((t_ret = __memp_fput(mpf, meta, 0)) != 0 && ret == 0)
		ret = t_ret;
	if (cp->page != NULL && (t_ret = __qam_fput(dbp, cp->pgno,
	    cp->page, ret == 0 ? DB_MPOOL_DIRTY : 0)) != 0 && ret == 0)
		ret = t_ret;
	cp->page = NULL;

	/* Doing record locking, release the page lock */
	if ((t_ret = __LPUT(dbc, cp->lock)) != 0 && ret == 0)
		ret = t_ret;
	cp->lock = lock;

	return (ret);
}

#ifdef	DEBUG_WOP
#define	QDEBUG
#endif

/*
 * __qam_c_get --
 *	Queue cursor->c_get function.
 */
static int
__qam_c_get(dbc, key, data, flags, pgnop)
	DBC *dbc;
	DBT *key, *data;
	u_int32_t flags;
	db_pgno_t *pgnop;
{
	DB *dbp;
	DBC *dbcdup;
	DBT tmp;
	DB_ENV *dbenv;
	DB_LOCK lock, pglock, metalock;
	DB_MPOOLFILE *mpf;
	PAGE *pg;
	QAMDATA *qp;
	QMETA *meta;
	QUEUE *t;
	QUEUE_CURSOR *cp;
	db_lockmode_t lock_mode;
	db_pgno_t metapno;
	db_recno_t first;
	qam_position_mode mode;
	int exact, inorder, is_first, locked, ret, t_ret, wait, with_delete;
	int put_mode, retrying;

	dbp = dbc->dbp;
	dbenv = dbp->dbenv;
	mpf = dbp->mpf;
	cp = (QUEUE_CURSOR *)dbc->internal;

	PANIC_CHECK(dbenv);

	wait = 0;
	with_delete = 0;
	retrying = 0;
	lock_mode = DB_LOCK_READ;
	meta = NULL;
	inorder = F_ISSET(dbp, DB_AM_INORDER);
	put_mode = 0;
	t_ret = 0;
	*pgnop = 0;
	pg = NULL;

	mode = QAM_READ;
	if (F_ISSET(dbc, DBC_RMW)) {
		lock_mode = DB_LOCK_WRITE;
		mode = QAM_WRITE;
	}

	if (flags == DB_CONSUME_WAIT) {
		wait = 1;
		flags = DB_CONSUME;
	}
	if (flags == DB_CONSUME) {
		with_delete = 1;
		flags = DB_FIRST;
		lock_mode = DB_LOCK_WRITE;
		mode = QAM_CONSUME;
	}

	DEBUG_LREAD(dbc, dbc->txn, "qam_c_get",
	    flags == DB_SET || flags == DB_SET_RANGE ? key : NULL, NULL, flags);

	/* Make lint and friends happy. */
	locked = 0;

	is_first = 0;

	t = (QUEUE *)dbp->q_internal;
	metapno = t->q_meta;

	/*
	 * Get the meta page first, we don't want to write lock it while
	 * trying to pin it.  This is because someone my have it pinned
	 * but not locked.
	 */
	if ((ret = __memp_fget(mpf, &metapno, 0, &meta)) != 0)
		return (ret);
	if ((ret = __db_lget(dbc, 0, metapno, lock_mode, 0, &metalock)) != 0)
		goto err;
	locked = 1;

	first = 0;

	/* Release any previous lock if not in a transaction. */
	if ((ret = __TLPUT(dbc, cp->lock)) != 0)
		goto err;

retry:	/* Update the record number. */
	switch (flags) {
	case DB_CURRENT:
		break;
	case DB_NEXT_DUP:
		ret = DB_NOTFOUND;
		goto err;
		/* NOTREACHED */
	case DB_NEXT:
	case DB_NEXT_NODUP:
get_next:	if (cp->recno != RECNO_OOB) {
			++cp->recno;
			/* Wrap around, skipping zero. */
			if (cp->recno == RECNO_OOB)
				cp->recno++;
			/*
			 * Check to see if we are out of data.
			 */
			if (cp->recno == meta->cur_recno ||
			    QAM_AFTER_CURRENT(meta, cp->recno)) {
				pg = NULL;
				if (!wait) {
					ret = DB_NOTFOUND;
					goto err;
				}
				flags = DB_FIRST;
				/*
				 * If first is not set, then we skipped
				 * a locked record, go back and find it.
				 * If we find a locked record again
				 * wait for it.
				 */
				if (first == 0) {
					retrying = 1;
					goto retry;
				}

				if (CDB_LOCKING(dbenv)) {
					/* Drop the metapage before we wait. */
					if ((ret =
					    __memp_fput(mpf, meta, 0)) != 0)
						goto err;
					meta = NULL;
					if ((ret = __lock_get(
					    dbenv, dbc->locker,
					    DB_LOCK_SWITCH, &dbc->lock_dbt,
					    DB_LOCK_WAIT, &dbc->mylock)) != 0)
						goto err;

					if ((ret = __memp_fget(mpf,
					     &metapno, 0, &meta)) != 0)
						goto err;
					if ((ret = __lock_get(
					    dbenv, dbc->locker,
					    DB_LOCK_UPGRADE, &dbc->lock_dbt,
					    DB_LOCK_WRITE, &dbc->mylock)) != 0)
						goto err;
					goto retry;
				}
				/*
				 * Wait for someone to update the meta page.
				 * This will probably mean there is something
				 * in the queue.  We then go back up and
				 * try again.
				 */
				if (locked == 0) {
					if ((ret = __db_lget(dbc, 0, metapno,
					     lock_mode, 0, &metalock)) != 0)
						goto err;
					locked = 1;
					if (cp->recno != meta->cur_recno &&
					    cp->recno != RECNO_OOB &&
					    !QAM_AFTER_CURRENT(meta, cp->recno))
						goto retry;
				}
				/* Drop the metapage before we wait. */
				if ((ret = __memp_fput(mpf, meta, 0)) != 0)
					goto err;
				meta = NULL;
				if ((ret = __db_lget(dbc,
				     0, metapno, DB_LOCK_WAIT,
				     DB_LOCK_SWITCH, &metalock)) != 0) {
					if (ret == DB_LOCK_DEADLOCK)
						ret = DB_LOCK_NOTGRANTED;
					goto err;
				}
				if ((ret = __memp_fget(
				     mpf, &metapno, 0, &meta)) != 0)
					goto err;
				if ((ret = __db_lget(dbc, 0,
				     PGNO_INVALID, DB_LOCK_WRITE,
				     DB_LOCK_UPGRADE, &metalock)) != 0) {
					if (ret == DB_LOCK_DEADLOCK)
						ret = DB_LOCK_NOTGRANTED;
					goto err;
				}
				locked = 1;
				goto retry;
			}
			break;
		}
		/* FALLTHROUGH */
	case DB_FIRST:
		flags = DB_NEXT;
		is_first = 1;

		/* get the first record number */
		cp->recno = first = meta->first_recno;

		break;
	case DB_PREV:
	case DB_PREV_NODUP:
		if (cp->recno != RECNO_OOB) {
			if (cp->recno == meta->first_recno ||
			   QAM_BEFORE_FIRST(meta, cp->recno)) {
				ret = DB_NOTFOUND;
				goto err;
			}
			--cp->recno;
			/* Wrap around, skipping zero. */
			if (cp->recno == RECNO_OOB)
				--cp->recno;
			break;
		}
		/* FALLTHROUGH */
	case DB_LAST:
		if (meta->first_recno == meta->cur_recno) {
			ret = DB_NOTFOUND;
			goto err;
		}
		cp->recno = meta->cur_recno - 1;
		if (cp->recno == RECNO_OOB)
			cp->recno--;
		break;
	case DB_SET:
	case DB_SET_RANGE:
	case DB_GET_BOTH:
	case DB_GET_BOTH_RANGE:
		if ((ret = __qam_getno(dbp, key, &cp->recno)) != 0)
			goto err;
		if (QAM_NOT_VALID(meta, cp->recno)) {
			ret = DB_NOTFOUND;
			goto err;
		}
		break;
	default:
		ret = __db_unknown_flag(dbenv, "__qam_c_get", flags);
		goto err;
	}

	/* Don't hold the meta page long term. */
	if (locked) {
		if ((ret = __LPUT(dbc, metalock)) != 0)
			goto err;
		locked = 0;
	}

	/* Lock the record. */
	if ((ret = __db_lget(dbc, 0, cp->recno, lock_mode,
	    (with_delete && !retrying) ?
	    DB_LOCK_NOWAIT | DB_LOCK_RECORD : DB_LOCK_RECORD,
	    &lock)) == DB_LOCK_DEADLOCK && with_delete) {
#ifdef QDEBUG
		__db_logmsg(dbenv,
		    dbc->txn, "Queue S", 0, "%x %d %d %d",
		    dbc->locker, cp->recno, first, meta->first_recno);
#endif
		first = 0;
		if ((ret =
		    __db_lget(dbc, 0, metapno, lock_mode, 0, &metalock)) != 0)
			goto err;
		locked = 1;
		goto retry;
	}

	if (ret != 0)
		goto err;

	/*
	 * In the DB_FIRST or DB_LAST cases we must wait and then start over
	 * since the first/last may have moved while we slept.
	 * We release our locks and try again.
	 */
	if (((inorder || !with_delete) && is_first) || flags == DB_LAST) {
get_first:
		if ((ret =
		    __db_lget(dbc, 0, metapno, lock_mode, 0, &metalock)) != 0)
			goto err;
		if (cp->recno !=
		    (is_first ? meta->first_recno : (meta->cur_recno - 1))) {
			if ((ret = __LPUT(dbc, lock)) != 0)
				goto err;
			if (is_first)
				flags = DB_FIRST;
			locked = 1;
			goto retry;
		}
		/* Don't hold the meta page long term. */
		if ((ret = __LPUT(dbc, metalock)) != 0)
			goto err;
	}

	/* Position the cursor on the record. */
	if ((ret = __qam_position(dbc, &cp->recno, mode, &exact)) != 0) {
		/* We cannot get the page, release the record lock. */
		(void)__LPUT(dbc, lock);
		goto err;
	}

	pg = cp->page;
	pglock = cp->lock;
	cp->lock = lock;
	cp->lock_mode = lock_mode;

	if (!exact) {
release_retry:	/* Release locks and retry, if possible. */
		if (pg != NULL)
			(void)__qam_fput(dbp, cp->pgno, pg, 0);
		cp->page = pg = NULL;
		if ((ret = __LPUT(dbc, pglock)) != 0)
			goto err1;

		switch (flags) {
		case DB_GET_BOTH_RANGE:
			flags = DB_SET_RANGE;
			/* FALLTHROUGH */
		case DB_NEXT:
		case DB_NEXT_NODUP:
		case DB_SET_RANGE:
			if (!with_delete)
				is_first = 0;
			/* Peek at the meta page unlocked. */
			if (QAM_BEFORE_FIRST(meta, cp->recno))
				goto get_first;
			/* FALLTHROUGH */
		case DB_PREV:
		case DB_PREV_NODUP:
		case DB_LAST:
			if (flags == DB_LAST)
				flags = DB_PREV;
			retrying = 0;
			if ((ret = __LPUT(dbc, cp->lock)) != 0)
				goto err1;
			if (flags == DB_SET_RANGE)
				goto get_next;
			else
				goto retry;

		default:
			/* this is for the SET and GET_BOTH cases */
			ret = DB_KEYEMPTY;
			goto err1;
		}
	}

	qp = QAM_GET_RECORD(dbp, pg, cp->indx);

	/* Return the data item. */
	if (flags == DB_GET_BOTH || flags == DB_GET_BOTH_RANGE) {
		/*
		 * Need to compare
		 */
		tmp.data = qp->data;
		tmp.size = t->re_len;
		if ((ret = __bam_defcmp(dbp, data, &tmp)) != 0) {
			if (flags == DB_GET_BOTH_RANGE)
				goto release_retry;
			ret = DB_NOTFOUND;
			goto err1;
		}
	}

	/* Return the key if the user didn't give us one. */
	if (key != NULL) {
		if (flags != DB_GET_BOTH && flags != DB_SET &&
		    (ret = __db_retcopy(dbp->dbenv,
		    key, &cp->recno, sizeof(cp->recno),
		    &dbc->rkey->data, &dbc->rkey->ulen)) != 0)
			goto err1;
		F_SET(key, DB_DBT_ISSET);
	}

	if (data != NULL) {
		if (!F_ISSET(dbc, DBC_MULTIPLE|DBC_MULTIPLE_KEY) &&
		    (ret = __db_retcopy(dbp->dbenv, data, qp->data, t->re_len,
		    &dbc->rdata->data, &dbc->rdata->ulen)) != 0)
			goto err1;
		F_SET(data, DB_DBT_ISSET);
	}

	/* Finally, if we are doing DB_CONSUME mark the record. */
	if (with_delete) {
		/*
		 * Assert that we're not a secondary index.  Doing a DB_CONSUME
		 * on a secondary makes very little sense, since one can't
		 * DB_APPEND there;  attempting one should be forbidden by
		 * the interface.
		 */
		DB_ASSERT(!F_ISSET(dbp, DB_AM_SECONDARY));

		/*
		 * Check and see if we *have* any secondary indices.
		 * If we do, we're a primary, so call __db_c_del_primary
		 * to delete the references to the item we're about to
		 * delete.
		 *
		 * Note that we work on a duplicated cursor, since the
		 * __db_ret work has already been done, so it's not safe
		 * to perform any additional ops on this cursor.
		 */
		if (LIST_FIRST(&dbp->s_secondaries) != NULL) {
			if ((ret = __db_c_idup(dbc,
			    &dbcdup, DB_POSITION)) != 0)
				goto err1;

			if ((ret = __db_c_del_primary(dbcdup)) != 0) {
				/*
				 * The __db_c_del_primary return is more
				 * interesting.
				 */
				(void)__db_c_close(dbcdup);
				goto err1;
			}

			if ((ret = __db_c_close(dbcdup)) != 0)
				goto err1;
		}

		if (DBC_LOGGING(dbc)) {
			if (t->page_ext == 0 || t->re_len == 0) {
				if ((ret = __qam_del_log(dbp, dbc->txn,
				    &LSN(pg), 0, &LSN(pg),
				    pg->pgno, cp->indx, cp->recno)) != 0)
					goto err1;
			} else {
				tmp.data = qp->data;
				tmp.size = t->re_len;
				if ((ret = __qam_delext_log(dbp,
				   dbc->txn, &LSN(pg), 0, &LSN(pg),
				   pg->pgno, cp->indx, cp->recno, &tmp)) != 0)
					goto err1;
			}
		}

		F_CLR(qp, QAM_VALID);
		put_mode = DB_MPOOL_DIRTY;

		if ((ret = __LPUT(dbc, pglock)) != 0)
			goto err1;

		/*
		 * Now we need to update the metapage
		 * first pointer. If we have deleted
		 * the record that is pointed to by
		 * first_recno then we move it as far
		 * forward as we can without blocking.
		 * The metapage lock must be held for
		 * the whole scan otherwise someone could
		 * do a random insert behind where we are
		 * looking.
		 */

		if (locked == 0 && (ret = __db_lget(
		    dbc, 0, metapno, lock_mode, 0, &metalock)) != 0)
			goto err1;
		locked = 1;

#ifdef QDEBUG
		__db_logmsg(dbenv,
		    dbc->txn, "Queue D", 0, "%x %d %d %d",
		    dbc->locker, cp->recno, first, meta->first_recno);
#endif
		/*
		 * See if we deleted the "first" record.  If
		 * first is zero then we skipped something,
		 * see if first_recno has been move passed
		 * that to the record that we deleted.
		 */
		if (first == 0)
			first = cp->recno;
		if (first != meta->first_recno)
			goto done;

		if ((ret = __qam_consume(dbc, meta, first)) != 0)
			goto err1;
	}

done:
err1:	if (cp->page != NULL) {
		if ((t_ret = __qam_fput(
		    dbp, cp->pgno, cp->page, put_mode)) != 0 && ret == 0)
			ret = t_ret;

		/* Doing record locking, release the page lock */
		if ((t_ret = __LPUT(dbc, pglock)) != 0 && ret == 0)
			ret = t_ret;
		cp->page = NULL;
	}

err:	if (meta) {
		/* Release the meta page. */
		if ((t_ret = __memp_fput(mpf, meta, 0)) != 0 && ret == 0)
			ret = t_ret;

		/* Don't hold the meta page long term. */
		if (locked)
			if ((t_ret = __LPUT(dbc, metalock)) != 0 && ret == 0)
				ret = t_ret;
	}
	DB_ASSERT(!LOCK_ISSET(metalock));