/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1997, 1998
* Sleepycat Software. All rights reserved.
*/
#include "config.h"
#ifndef lint
static const char sccsid[] = "@(#)bt_recno.c 10.53 (Sleepycat) 12/11/98";
#endif /* not lint */
#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>
#include <errno.h>
#include <limits.h>
#include <string.h>
#endif
#include "db_int.h"
#include "db_page.h"
#include "btree.h"
#include "db_ext.h"
#include "shqueue.h"
#include "db_shash.h"
#include "lock.h"
#include "lock_ext.h"
static int __ram_add __P((DBC *, db_recno_t *, DBT *, u_int32_t, u_int32_t));
static int __ram_delete __P((DB *, DB_TXN *, DBT *, u_int32_t));
static int __ram_fmap __P((DBC *, db_recno_t));
static int __ram_i_delete __P((DBC *));
static int __ram_put __P((DB *, DB_TXN *, DBT *, DBT *, u_int32_t));
static int __ram_source __P((DB *, RECNO *, const char *));
static int __ram_sync __P((DB *, u_int32_t));
static int __ram_update __P((DBC *, db_recno_t, int));
static int __ram_vmap __P((DBC *, db_recno_t));
static int __ram_writeback __P((DBC *));
/*
* In recno, there are two meanings to the on-page "deleted" flag. If we're
* re-numbering records, it means the record was implicitly created. We skip
* over implicitly created records if doing a cursor "next" or "prev", and
* return DB_KEYEMPTY if they're explicitly requested.. If not re-numbering
* records, it means that the record was implicitly created, or was deleted.
* We skip over implicitly created or deleted records if doing a cursor "next"
* or "prev", and return DB_KEYEMPTY if they're explicitly requested.
*
* If we're re-numbering records, then we have to detect in the cursor that
* a record was deleted, and adjust the cursor as necessary on the next get.
* If we're not re-numbering records, then we can detect that a record has
* been deleted by looking at the actual on-page record, so we completely
* ignore the cursor's delete flag. This is different from the B+tree code.
* It also maintains whether the cursor references a deleted record in the
* cursor, and it doesn't always check the on-page value.
*/
#define CD_SET(dbp, cp) { \
if (F_ISSET(dbp, DB_RE_RENUMBER)) \
F_SET(cp, C_DELETED); \
}
#define CD_CLR(dbp, cp) { \
if (F_ISSET(dbp, DB_RE_RENUMBER)) \
F_CLR(cp, C_DELETED); \
}
#define CD_ISSET(dbp, cp) \
(F_ISSET(dbp, DB_RE_RENUMBER) && F_ISSET(cp, C_DELETED))
/*
* __ram_open --
* Recno open function.
*
* PUBLIC: int __ram_open __P((DB *, DB_INFO *));
*/
int
__ram_open(dbp, dbinfo)
DB *dbp;
DB_INFO *dbinfo;
{
BTREE *t;
DBC *dbc;
RECNO *rp;
int ret, t_ret;
/* Allocate and initialize the private btree structure. */
if ((ret = __os_calloc(1, sizeof(BTREE), &t)) != 0)
return (ret);
dbp->internal = t;
__bam_setovflsize(dbp);
/* Allocate and initialize the private recno structure. */
if ((ret = __os_calloc(1, sizeof(*rp), &rp)) != 0)
return (ret);
/* Link in the private recno structure. */
t->recno = rp;
/*
* Intention is to make sure all of the user's selections are okay
* here and then use them without checking.
*/
if (dbinfo == NULL) {
rp->re_delim = '\n';
rp->re_pad = ' ';
rp->re_fd = -1;
F_SET(rp, RECNO_EOF);
} else {
/*
* If the user specified a source tree, open it and map it in.
*
* !!!
* We don't complain if the user specified transactions or
* threads. It's possible to make it work, but you'd better
* know what you're doing!
*/
if (dbinfo->re_source == NULL) {
rp->re_fd = -1;
F_SET(rp, RECNO_EOF);
} else {
if ((ret =
__ram_source(dbp, rp, dbinfo->re_source)) != 0)
goto err;
}
/* Copy delimiter, length and padding values. */
rp->re_delim =
F_ISSET(dbp, DB_RE_DELIMITER) ? dbinfo->re_delim : '\n';
rp->re_pad = F_ISSET(dbp, DB_RE_PAD) ? dbinfo->re_pad : ' ';
if (F_ISSET(dbp, DB_RE_FIXEDLEN)) {
if ((rp->re_len = dbinfo->re_len) == 0) {
__db_err(dbp->dbenv,
"record length must be greater than 0");
ret = EINVAL;
goto err;
}
} else
rp->re_len = 0;
}
/* Initialize the remaining fields/methods of the DB. */
dbp->am_close = __ram_close;
dbp->del = __ram_delete;
dbp->put = __ram_put;
dbp->stat = __bam_stat;
dbp->sync = __ram_sync;
/* Start up the tree. */
if ((ret = __bam_read_root(dbp)) != 0)
goto err;
/* Set the overflow page size. */
__bam_setovflsize(dbp);
/* If we're snapshotting an underlying source file, do it now. */
if (dbinfo != NULL && F_ISSET(dbinfo, DB_SNAPSHOT)) {
/* Allocate a cursor. */
if ((ret = dbp->cursor(dbp, NULL, &dbc, 0)) != 0)
goto err;
/* Do the snapshot. */
if ((ret = __ram_update(dbc,
DB_MAX_RECORDS, 0)) != 0 && ret == DB_NOTFOUND)
ret = 0;
/* Discard the cursor. */
if ((t_ret = dbc->c_close(dbc)) != 0 && ret == 0)
ret = t_ret;
if (ret != 0)
goto err;
}
return (0);
err: /* If we mmap'd a source file, discard it. */
if (rp->re_smap != NULL)
(void)__db_unmapfile(rp->re_smap, rp->re_msize);
/* If we opened a source file, discard it. */
if (rp->re_fd != -1)
(void)__os_close(rp->re_fd);
if (rp->re_source != NULL)
__os_freestr(rp->re_source);
__os_free(rp, sizeof(*rp));
return (ret);
}
/*
* __ram_delete --
* Recno db->del function.
*/
static int
__ram_delete(dbp, txn, key, flags)
DB *dbp;
DB_TXN *txn;
DBT *key;
u_int32_t flags;
{
CURSOR *cp;
DBC *dbc;
db_recno_t recno;
int ret, t_ret;
DB_PANIC_CHECK(dbp);
/* Check for invalid flags. */
if ((ret = __db_delchk(dbp,
key, flags, F_ISSET(dbp, DB_AM_RDONLY))) != 0)
return (ret);
/* Acquire a cursor. */
if ((ret = dbp->cursor(dbp, txn, &dbc, DB_WRITELOCK)) != 0)
return (ret);
DEBUG_LWRITE(dbc, txn, "ram_delete", key, NULL, flags);
/* Check the user's record number and fill in as necessary. */
if ((ret = __ram_getno(dbc, key, &recno, 0)) != 0)
goto err;
/* Do the delete. */
cp = dbc->internal;
cp->recno = recno;
ret = __ram_i_delete(dbc);
/* Release the cursor. */
err: if ((t_ret = dbc->c_close(dbc)) != 0 && ret == 0)
ret = t_ret;
return (ret);
}
/*
* __ram_i_delete --
* Internal version of recno delete, called by __ram_delete and
* __ram_c_del.
*/
static int
__ram_i_delete(dbc)
DBC *dbc;
{
BKEYDATA bk;
BTREE *t;
CURSOR *cp;
DB *dbp;
DBT hdr, data;
PAGE *h;
db_indx_t indx;
int exact, ret, stack;
dbp = dbc->dbp;
cp = dbc->internal;
t = dbp->internal;
stack = 0;
/*
* If this is CDB and this isn't a write cursor, then it's an error.
* If it is a write cursor, but we don't yet hold the write lock, then
* we need to upgrade to the write lock.
*/
if (F_ISSET(dbp, DB_AM_CDB)) {
/* Make sure it's a valid update cursor. */
if (!F_ISSET(dbc, DBC_RMW | DBC_WRITER))
return (EINVAL);
if (F_ISSET(dbc, DBC_RMW) &&
(ret = lock_get(dbp->dbenv->lk_info, dbc->locker,
DB_LOCK_UPGRADE, &dbc->lock_dbt, DB_LOCK_WRITE,
&dbc->mylock)) != 0)
return (EAGAIN);
}
/* Search the tree for the key; delete only deletes exact matches. */
if ((ret = __bam_rsearch(dbc, &cp->recno, S_DELETE, 1, &exact)) != 0)
goto err;
if (!exact) {
ret = DB_NOTFOUND;
goto err;
}
stack = 1;
h = cp->csp->page;
indx = cp->csp->indx;
/*
* If re-numbering records, the on-page deleted flag can only mean
* that this record was implicitly created. Applications aren't
* permitted to delete records they never created, return an error.
*
* If not re-numbering records, the on-page deleted flag means that
* this record was implicitly created, or, was deleted at some time.
* The former is an error because applications aren't permitted to
* delete records they never created, the latter is an error because
* if the record was "deleted", we could never have found it.
*/
if (B_DISSET(GET_BKEYDATA(h, indx)->type)) {
ret = DB_KEYEMPTY;
goto err;
}
if (F_ISSET(dbp, DB_RE_RENUMBER)) {
/* Delete the item, adjust the counts, adjust the cursors. */
if ((ret = __bam_ditem(dbc, h, indx)) != 0)
goto err;
__bam_adjust(dbc, -1);
__ram_ca(dbp, cp->recno, CA_DELETE);
/*
* If the page is empty, delete it. The whole tree is locked
* so there are no preparations to make.
*/
if (NUM_ENT(h) == 0 && h->pgno != PGNO_ROOT) {
stack = 0;
ret = __bam_dpages(dbc);
}
} else {
/* Use a delete/put pair to replace the record with a marker. */
if ((ret = __bam_ditem(dbc, h, indx)) != 0)
goto err;
B_TSET(bk.type, B_KEYDATA, 1);
bk.len = 0;
memset(&hdr, 0, sizeof(hdr));
hdr.data = &bk;
hdr.size = SSZA(BKEYDATA, data);
memset(&data, 0, sizeof(data));
data.data = (char *)"";
data.size = 0;
if ((ret = __db_pitem(dbc,
h, indx, BKEYDATA_SIZE(0), &hdr, &data)) != 0)
goto err;
}
F_SET(t->recno, RECNO_MODIFIED);
err: if (stack)
__bam_stkrel(dbc, 0);
/* If we upgraded the CDB lock upon entry; downgrade it now. */
if (F_ISSET(dbp, DB_AM_CDB) && F_ISSET(dbc, DBC_RMW))
(void)__lock_downgrade(dbp->dbenv->lk_info, dbc->mylock,
DB_LOCK_IWRITE, 0);
return (ret);
}
/*
* __ram_put --
* Recno db->put function.
*/
static int
__ram_put(dbp, txn, key, data, flags)
DB *dbp;
DB_TXN *txn;
DBT *key, *data;
u_int32_t flags;
{
DBC *dbc;
db_recno_t recno;
int ret, t_ret;
DB_PANIC_CHECK(dbp);
/* Check for invalid flags. */
if ((ret = __db_putchk(dbp,
key, data, flags, F_ISSET(dbp, DB_AM_RDONLY), 0)) != 0)
return (ret);
/* Allocate a cursor. */
if ((ret = dbp->cursor(dbp, txn, &dbc, DB_WRITELOCK)) != 0)
return (ret);
DEBUG_LWRITE(dbc, txn, "ram_put", key, data, flags);
/*
* If we're appending to the tree, make sure we've read in all of
* the backing source file. Otherwise, check the user's record
* number and fill in as necessary.
*/
ret = flags == DB_APPEND ?
__ram_update(dbc, DB_MAX_RECORDS, 0) :
__ram_getno(dbc, key, &recno, 1);
/* Add the record. */
if (ret == 0)
ret = __ram_add(dbc, &recno, data, flags, 0);
/* Discard the cursor. */
if ((t_ret = dbc->c_close(dbc)) != 0 && ret == 0)
ret = t_ret;
/* Return the record number if we're appending to the tree. */
if (ret == 0 && flags == DB_APPEND)
*(db_recno_t *)key->data = recno;
return (ret);
}
/*
* __ram_sync --
* Recno db->sync function.
*/
static int
__ram_sync(dbp, flags)
DB *dbp;
u_int32_t flags;
{
DBC *dbc;
int ret, t_ret;
/*
* Sync the underlying btree.
*
* !!!
* We don't need to do a panic check or flags check, the "real"
* sync function does all that for us.
*/
if ((ret = __db_sync(dbp, flags)) != 0)
return (ret);
/* Allocate a cursor. */
if ((ret = dbp->cursor(dbp, NULL, &dbc, 0)) != 0)
return (ret);
DEBUG_LWRITE(dbc, NULL, "ram_sync", NULL, NULL, flags);
/* Copy back the backing source file. */
ret = __ram_writeback(dbc);
/* Discard the cursor. */
if ((t_ret = dbc->c_close(dbc)) != 0 && ret == 0)
ret = t_ret;
return (ret);
}
/*
* __ram_close --
* Recno db->close function.
*
* PUBLIC: int __ram_close __P((DB *));
*/
int
__ram_close(dbp)
DB *dbp;
{
RECNO *rp;
rp = ((BTREE *)dbp->internal)->recno;
/* Close any underlying mmap region. */
if (rp->re_smap != NULL)
(void)__db_unmapfile(rp->re_smap, rp->re_msize);
/* Close any backing source file descriptor. */
if (rp->re_fd != -1)
(void)__os_close(rp->re_fd);
/* Free any backing source file name. */
if (rp->re_source != NULL)
__os_freestr(rp->re_source);
/* Free allocated memory. */
__os_free(rp, sizeof(RECNO));
((BTREE *)dbp->internal)->recno = NULL;
/* Close the underlying btree. */
return (__bam_close(dbp));
}
/*
* __ram_c_del --
* Recno cursor->c_del function.
*
* PUBLIC: int __ram_c_del __P((DBC *, u_int32_t));
*/
int
__ram_c_del(dbc, flags)
DBC *dbc;
u_int32_t flags;
{
CURSOR *cp;
DB *dbp;
int ret;
dbp = dbc->dbp;
cp = dbc->internal;
DB_PANIC_CHECK(dbp);
/* Check for invalid flags. */
if ((ret = __db_cdelchk(dbp, flags,
F_ISSET(dbp, DB_AM_RDONLY), cp->recno != RECNO_OOB)) != 0)
return (ret);
DEBUG_LWRITE(dbc, dbc->txn, "ram_c_del", NULL, NULL, flags);
/*
* If we are running CDB, this had better be either a write
* cursor or an immediate writer.
*/
if (F_ISSET(dbp, DB_AM_CDB))
if (!F_ISSET(dbc, DBC_RMW | DBC_WRITER))
return (EINVAL);
/*
* The semantics of cursors during delete are as follows: if record
* numbers are mutable (DB_RE_RENUMBER is set), deleting a record
* causes the cursor to automatically point to the record immediately
* following. In this case it is possible to use a single cursor for
* repeated delete operations, without intervening operations.
*
* If record numbers are not mutable, then records are replaced with
* a marker containing a delete flag. If the record referenced by
* this cursor has already been deleted, we will detect that as part
* of the delete operation, and fail.
*/
return (__ram_i_delete(dbc));
}
/*
* __ram_c_get --
* Recno cursor->c_get function.
*
* PUBLIC: int __ram_c_get __P((DBC *, DBT *, DBT *, u_int32_t));
*/
int
__ram_c_get(dbc, key, data, flags)
DBC *dbc;
DBT *key, *data;
u_int32_t flags;
{
CURSOR *cp, copy;
DB *dbp;
PAGE *h;
db_indx_t indx;
int exact, ret, stack, tmp_rmw;
dbp = dbc->dbp;
cp = dbc->internal;
DB_PANIC_CHECK(dbp);
/* Check for invalid flags. */
if ((ret = __db_cgetchk(dbc->dbp,
key, data, flags, cp->recno != RECNO_OOB)) != 0)
return (ret);
/* Clear OR'd in additional bits so we can check for flag equality. */
tmp_rmw = 0;
if (LF_ISSET(DB_RMW)) {
if (!F_ISSET(dbp, DB_AM_CDB)) {
tmp_rmw = 1;
F_SET(dbc, DBC_RMW);
}
LF_CLR(DB_RMW);
}
DEBUG_LREAD(dbc, dbc->txn, "ram_c_get",
flags == DB_SET || flags == DB_SET_RANGE ? key : NULL, NULL, flags);
/* Initialize the cursor for a new retrieval. */
copy = *cp;
retry: /* Update the record number. */
stack = 0;
switch (flags) {
case DB_CURRENT:
/*
* If record numbers are mutable: if we just deleted a record,
* there is no action necessary, we return the record following
* the deleted item by virtue of renumbering the tree.
*/
break;
case DB_NEXT:
/*
* If record numbers are mutable: if we just deleted a record,
* we have to avoid incrementing the record number so that we
* return the right record by virtue of renumbering the tree.
*/
if (CD_ISSET(dbp, cp))
break;
if (cp->recno != RECNO_OOB) {
++cp->recno;
break;
}
/* FALLTHROUGH */
case DB_FIRST:
flags = DB_NEXT;
cp->recno = 1;
break;
case DB_PREV:
if (cp->recno != RECNO_OOB) {
if (cp->recno == 1) {
ret = DB_NOTFOUND;
goto err;
}
--cp->recno;
break;
}
/* FALLTHROUGH */
case DB_LAST:
flags = DB_PREV;
if (((ret = __ram_update(dbc,
DB_MAX_RECORDS, 0)) != 0) && ret != DB_NOTFOUND)
goto err;
if ((ret = __bam_nrecs(dbc, &cp->recno)) != 0)
goto err;
if (cp->recno == 0) {
ret = DB_NOTFOUND;
goto err;
}
break;
case DB_SET:
case DB_SET_RANGE:
if ((ret = __ram_getno(dbc, key, &cp->recno, 0)) != 0)
goto err;
break;
}
/* Return the key if the user didn't give us one. */
if (flags != DB_SET && flags != DB_SET_RANGE &&
(ret = __db_retcopy(key, &cp->recno, sizeof(cp->recno),
&dbc->rkey.data, &dbc->rkey.ulen, dbp->db_malloc)) != 0)
goto err;
/* Search the tree for the record. */
if ((ret = __bam_rsearch(dbc, &cp->recno,
F_ISSET(dbc, DBC_RMW) ? S_FIND_WR : S_FIND, 1, &exact)) != 0)
goto err;
stack = 1;
if (!exact) {
ret = DB_NOTFOUND;
goto err;
}
h = cp->csp->page;
indx = cp->csp->indx;
/*
* If re-numbering records, the on-page deleted flag means this record
* was implicitly created. If not re-numbering records, the on-page
* deleted flag means this record was implicitly created, or, it was
* deleted at some time. Regardless, we skip such records if doing
* cursor next/prev operations, and fail if the application requested
* them explicitly.
*/
if (B_DISSET(GET_BKEYDATA(h, indx)->type)) {
if (flags == DB_NEXT || flags == DB_PREV) {
(void)__bam_stkrel(dbc, 0);
goto retry;
}
ret = DB_KEYEMPTY;
goto err;
}
/* Return the data item. */
if ((ret = __db_ret(dbp,
h, indx, data, &dbc->rdata.data, &dbc->rdata.ulen)) != 0)
goto err;
/* The cursor was reset, no further delete adjustment is necessary. */
CD_CLR(dbp, cp);
err: if (stack)
(void)__bam_stkrel(dbc, 0);
/* Release temporary lock upgrade. */
if (tmp_rmw)
F_CLR(dbc, DBC_RMW);
if (ret != 0)
*cp = copy;
return (ret);
}
/*
* __ram_c_put --
* Recno cursor->c_put function.
*
* PUBLIC: int __ram_c_put __P((DBC *, DBT *, DBT *, u_int32_t));
*/
int
__ram_c_put(dbc, key, data, flags)
DBC *dbc;
DBT *key, *data;
u_int32_t flags;
{
CURSOR *cp, copy;
DB *dbp;
int exact, ret;
void *arg;
dbp = dbc->dbp;
cp = dbc->internal;
DB_PANIC_CHECK(dbp);
if ((ret = __db_cputchk(dbc->dbp, key, data, flags,
F_ISSET(dbc->dbp, DB_AM_RDONLY), cp->recno != RECNO_OOB)) != 0)
return (ret);
DEBUG_LWRITE(dbc, dbc->txn, "ram_c_put", NULL, data, flags);
/*
* If we are running CDB, this had better be either a write
* cursor or an immediate writer. If it's a regular writer,
* that means we have an IWRITE lock and we need to upgrade
* it to a write lock.
*/
if (F_ISSET(dbp, DB_AM_CDB)) {
if (!F_ISSET(dbc, DBC_RMW | DBC_WRITER))
return (EINVAL);
if (F_ISSET(dbc, DBC_RMW) &&
(ret = lock_get(dbp->dbenv->lk_info, dbc->locker,
DB_LOCK_UPGRADE, &dbc->lock_dbt, DB_LOCK_WRITE,
&dbc->mylock)) != 0)
return (EAGAIN);
}
/* Initialize the cursor for a new retrieval. */
copy = *cp;
/*
* To split, we need a valid key for the page. Since it's a cursor,
* we have to build one.
*
* The split code discards all short-term locks and stack pages.
*/
if (0) {
split: arg = &cp->recno;
if ((ret = __bam_split(dbc, arg)) != 0)
goto err;
}
if ((ret = __bam_rsearch(dbc, &cp->recno, S_INSERT, 1, &exact)) != 0)
goto err;
if (!exact) {
ret = DB_NOTFOUND;
goto err;
}
if ((ret = __bam_iitem(dbc, &cp->csp->page,
&cp->csp->indx, key, data, flags, 0)) == DB_NEEDSPLIT) {
if ((ret = __bam_stkrel(dbc, 0)) != 0)
goto err;
goto split;
}
if ((ret = __bam_stkrel(dbc, 0)) != 0)
goto err;
switch (flags) {
case DB_AFTER:
/* Adjust the cursors. */
__ram_ca(dbp, cp->recno, CA_IAFTER);
/* Set this cursor to reference the new record. */
cp->recno = copy.recno + 1;
break;
case DB_BEFORE:
/* Adjust the cursors. */
__ram_ca(dbp, cp->recno, CA_IBEFORE);
/* Set this cursor to reference the new record. */
cp->recno = copy.recno;
break;
}
/* The cursor was reset, no further delete adjustment is necessary. */
CD_CLR(dbp, cp);
err: if (F_ISSET(dbp, DB_AM_CDB) && F_ISSET(dbc, DBC_RMW))
(void)__lock_downgrade(dbp->dbenv->lk_info, dbc->mylock,
DB_LOCK_IWRITE, 0);
if (ret != 0)
*cp = copy;
return (ret);
}
/*
* __ram_ca --
* Adjust cursors.
*
* PUBLIC: void __ram_ca __P((DB *, db_recno_t, ca_recno_arg));
*/
void
__ram_ca(dbp, recno, op)
DB *dbp;
db_recno_t recno;
ca_recno_arg op;
{
CURSOR *cp;
DBC *dbc;
/*
* Adjust the cursors. See the comment in __bam_ca_delete().
*/
DB_THREAD_LOCK(dbp);
for (dbc = TAILQ_FIRST(&dbp->active_queue);
dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
cp = dbc->internal;
switch (op) {
case CA_DELETE:
if (recno > cp->recno)
--cp->recno;
if (recno == cp->recno)
CD_SET(dbp, cp);
break;
case CA_IAFTER:
if (recno > cp->recno)
++cp->recno;
break;
case CA_IBEFORE:
if (recno >= cp->recno)
++cp->recno;
break;
}
}
DB_THREAD_UNLOCK(dbp);
}
/*
* __ram_getno --
* Check the user's record number, and make sure we've seen it.
*
* PUBLIC: int __ram_getno __P((DBC *, const DBT *, db_recno_t *, int));
*/
int
__ram_getno(dbc, key, rep, can_create)
DBC *dbc;
const DBT *key;
db_recno_t *rep;
int can_create;
{
DB *dbp;
db_recno_t recno;
dbp = dbc->dbp;
/* Check the user's record number. */
if ((recno = *(db_recno_t *)key->data) == 0) {
__db_err(dbp->dbenv, "illegal record number of 0");
return (EINVAL);
}
if (rep != NULL)
*rep = recno;
/*
* Btree can neither create records nor read them in. Recno can
* do both, see if we can find the record.
*/
return (dbp->type == DB_RECNO ?
__ram_update(dbc, recno, can_create) : 0);
}
/*
* __ram_update --
* Ensure the tree has records up to and including the specified one.
*/
static int
__ram_update(dbc, recno, can_create)
DBC *dbc;
db_recno_t recno;
int can_create;
{
BTREE *t;
DB *dbp;
RECNO *rp;
db_recno_t nrecs;
int ret;
dbp = dbc->dbp;
t = dbp->internal;
rp = t->recno;
/*
* If we can't create records and we've read the entire backing input
* file, we're done.
*/
if (!can_create && F_ISSET(rp, RECNO_EOF))
return (0);
/*
* If we haven't seen this record yet, try to get it from the original
* file.
*/
if ((ret = __bam_nrecs(dbc, &nrecs)) != 0)
return (ret);
if (!F_ISSET(rp, RECNO_EOF) && recno > nrecs) {
if ((ret = rp->re_irec(dbc, recno)) != 0)
return (ret);
if ((ret = __bam_nrecs(dbc, &nrecs)) != 0)
return (ret);
}
/*
* If we can create records, create empty ones up to the requested
* record.
*/
if (!can_create || recno <= nrecs + 1)
return (0);
dbc->rdata.dlen = 0;
dbc->rdata.doff = 0;
dbc->rdata.flags = 0;
if (F_ISSET(dbp, DB_RE_FIXEDLEN)) {
if (dbc->rdata.ulen < rp->re_len) {
if ((ret =
__os_realloc(&dbc->rdata.data, rp->re_len)) != 0) {
dbc->rdata.ulen = 0;
dbc->rdata.data = NULL;
return (ret);
}
dbc->rdata.ulen = rp->re_len;
}
dbc->rdata.size = rp->re_len;
memset(dbc->rdata.data, rp->re_pad, rp->re_len);
} else
dbc->rdata.size = 0;
while (recno > ++nrecs)
if ((ret = __ram_add(dbc,
&nrecs, &dbc->rdata, 0, BI_DELETED)) != 0)
return (ret);
return (0);
}
/*
* __ram_source --
* Load information about the backing file.
*/
static int
__ram_source(dbp, rp, fname)
DB *dbp;
RECNO *rp;
const char *fname;
{
size_t size;
u_int32_t bytes, mbytes, oflags;
int ret;
/*
* !!!
* The caller has full responsibility for cleaning up on error --
* (it has to anyway, in case it fails after this routine succeeds).
*/
if ((ret = __db_appname(dbp->dbenv,
DB_APP_DATA, NULL, fname, 0, NULL, &rp->re_source)) != 0)
return (ret);
oflags = F_ISSET(dbp, DB_AM_RDONLY) ? DB_RDONLY : 0;
if ((ret =
__db_open(rp->re_source, oflags, oflags, 0, &rp->re_fd)) != 0) {
__db_err(dbp->dbenv, "%s: %s", rp->re_source, strerror(ret));
return (ret);
}
/*
* XXX
* We'd like to test to see if the file is too big to mmap. Since we
* don't know what size or type off_t's or size_t's are, or the largest
* unsigned integral type is, or what random insanity the local C
* compiler will perpetrate, doing the comparison in a portable way is
* flatly impossible. Hope that mmap fails if the file is too large.
*/
if ((ret = __os_ioinfo(rp->re_source,
rp->re_fd, &mbytes, &bytes, NULL)) != 0) {
__db_err(dbp->dbenv, "%s: %s", rp->re_source, strerror(ret));
return (ret);
}
if (mbytes == 0 && bytes == 0) {
F_SET(rp, RECNO_EOF);
return (0);
}
size = mbytes * MEGABYTE + bytes;
if ((ret = __db_mapfile(rp->re_source,
rp->re_fd, (size_t)size, 1, &rp->re_smap)) != 0)
return (ret);
rp->re_cmap = rp->re_smap;
rp->re_emap = (u_int8_t *)rp->re_smap + (rp->re_msize = size);
rp->re_irec = F_ISSET(dbp, DB_RE_FIXEDLEN) ? __ram_fmap : __ram_vmap;
return (0);
}
/*
* __ram_writeback --
* Rewrite the backing file.
*/
static int
__ram_writeback(dbc)
DBC *dbc;
{
DB *dbp;
DBT key, data;
RECNO *rp;
db_recno_t keyno;
ssize_t nw;
int fd, ret, t_ret;
u_int8_t delim, *pad;
dbp = dbc->dbp;
rp = ((BTREE *)dbp->internal)->recno;
/* If the file wasn't modified, we're done. */
if (!F_ISSET(rp, RECNO_MODIFIED))
return (0);
/* If there's no backing source file, we're done. */
if (rp->re_source == NULL) {
F_CLR(rp, RECNO_MODIFIED);
return (0);
}
/*
* Read any remaining records into the tree.
*
* !!!
* This is why we can't support transactions when applications specify
* backing (re_source) files. At this point we have to read in the
* rest of the records from the file so that we can write all of the
* records back out again, which could modify a page for which we'd
* have to log changes and which we don't have locked. This could be
* partially fixed by taking a snapshot of the entire file during the
* db_open(), or, since db_open() isn't transaction protected, as part
* of the first DB operation. But, if a checkpoint occurs then, the
* part of the log holding the copy of the file could be discarded, and
* that would make it impossible to recover in the face of disaster.
* This could all probably be fixed, but it would require transaction
* protecting the backing source file, i.e. mpool would have to know
* about it, and we don't want to go there.
*/
if ((ret =
__ram_update(dbc, DB_MAX_RECORDS, 0)) != 0 && ret != DB_NOTFOUND)
return (ret);
/*
* !!!
* Close any underlying mmap region. This is required for Windows NT
* (4.0, Service Pack 2) -- if the file is still mapped, the following
* open will fail.
*/
if (rp->re_smap != NULL) {
(void)__db_unmapfile(rp->re_smap, rp->re_msize);
rp->re_smap = NULL;
}
/* Get rid of any backing file descriptor, just on GP's. */
if (rp->re_fd != -1) {
(void)__os_close(rp->re_fd);
rp->re_fd = -1;
}
/* Open the file, truncating it. */
if ((ret = __db_open(rp->re_source,
DB_SEQUENTIAL | DB_TRUNCATE,
DB_SEQUENTIAL | DB_TRUNCATE, 0, &fd)) != 0) {
__db_err(dbp->dbenv, "%s: %s", rp->re_source, strerror(ret));
return (ret);
}
/*
* We step through the records, writing each one out. Use the record
* number and the dbp->get() function, instead of a cursor, so we find
* and write out "deleted" or non-existent records.
*/
memset(&key, 0, sizeof(key));
memset(&data, 0, sizeof(data));
key.size = sizeof(db_recno_t);
key.data = &keyno;
/*
* We'll need the delimiter if we're doing variable-length records,
* and the pad character if we're doing fixed-length records.
*/
delim = rp->re_delim;
if (F_ISSET(dbp, DB_RE_FIXEDLEN)) {
if ((ret = __os_malloc(rp->re_len, NULL, &pad)) != 0)
goto err;
memset(pad, rp->re_pad, rp->re_len);
} else
COMPQUIET(pad, NULL);
for (keyno = 1;; ++keyno) {
switch (ret = dbp->get(dbp, NULL, &key, &data, 0)) {
case 0:
if ((ret =
__os_write(fd, data.data, data.size, &nw)) != 0)
goto err;
if (nw != (ssize_t)data.size) {
ret = EIO;
goto err;
}
break;
case DB_KEYEMPTY:
if (F_ISSET(dbp, DB_RE_FIXEDLEN)) {
if ((ret =
__os_write(fd, pad, rp->re_len, &nw)) != 0)
goto err;
if (nw != (ssize_t)rp->re_len) {
ret = EIO;
goto err;
}
}
break;
case DB_NOTFOUND:
ret = 0;
goto done;
}
if (!F_ISSET(dbp, DB_RE_FIXEDLEN)) {
if ((ret = __os_write(fd, &delim, 1, &nw)) != 0)
goto err;
if (nw != 1) {
ret = EIO;
goto err;
}
}
}
err:
done: /* Close the file descriptor. */
if ((t_ret = __os_close(fd)) != 0 || ret == 0)
ret = t_ret;
if (ret == 0)
F_CLR(rp, RECNO_MODIFIED);
return (ret);
}
/*
* __ram_fmap --
* Get fixed length records from a file.
*/
static int
__ram_fmap(dbc, top)
DBC *dbc;
db_recno_t top;
{
DB *dbp;
DBT data;
RECNO *rp;
db_recno_t recno;
u_int32_t len;
u_int8_t *sp, *ep, *p;
int ret;
if ((ret = __bam_nrecs(dbc, &recno)) != 0)
return (ret);
dbp = dbc->dbp;
rp = ((BTREE *)(dbp->internal))->recno;
if (dbc->rdata.ulen < rp->re_len) {
if ((ret = __os_realloc(&dbc->rdata.data, rp->re_len)) != 0) {
dbc->rdata.ulen = 0;
dbc->rdata.data = NULL;
return (ret);
}
dbc->rdata.ulen = rp->re_len;
}
memset(&data, 0, sizeof(data));
data.data = dbc->rdata.data;
data.size = rp->re_len;
sp = (u_int8_t *)rp->re_cmap;
ep = (u_int8_t *)rp->re_emap;
while (recno < top) {
if (sp >= ep) {
F_SET(rp, RECNO_EOF);
return (DB_NOTFOUND);
}
len = rp->re_len;
for (p = dbc->rdata.data;
sp < ep && len > 0; *p++ = *sp++, --len)
;
/*
* Another process may have read this record from the input
* file and stored it into the database already, in which
* case we don't need to repeat that operation. We detect
* this by checking if the last record we've read is greater
* or equal to the number of records in the database.
*
* XXX
* We should just do a seek, since the records are fixed
* length.
*/
if (rp->re_last >= recno) {
if (len != 0)
memset(p, rp->re_pad, len);
++recno;
if ((ret = __ram_add(dbc, &recno, &data, 0, 0)) != 0)
return (ret);
}
++rp->re_last;
}
rp->re_cmap = sp;
return (0);
}
/*
* __ram_vmap --
* Get variable length records from a file.
*/
static int
__ram_vmap(dbc, top)
DBC *dbc;
db_recno_t top;
{
DBT data;
RECNO *rp;
db_recno_t recno;
u_int8_t *sp, *ep;
int delim, ret;
rp = ((BTREE *)(dbc->dbp->internal))->recno;
if ((ret = __bam_nrecs(dbc, &recno)) != 0)
return (ret);
memset(&data, 0, sizeof(data));
delim = rp->re_delim;
sp = (u_int8_t *)rp->re_cmap;
ep = (u_int8_t *)rp->re_emap;
while (recno < top) {
if (sp >= ep) {
F_SET(rp, RECNO_EOF);
return (DB_NOTFOUND);
}
for (data.data = sp; sp < ep && *sp != delim; ++sp)
;
/*
* Another process may have read this record from the input
* file and stored it into the database already, in which
* case we don't need to repeat that operation. We detect
* this by checking if the last record we've read is greater
* or equal to the number of records in the database.
*/
if (rp->re_last >= recno) {
data.size = sp - (u_int8_t *)data.data;
++recno;
if ((ret = __ram_add(dbc, &recno, &data, 0, 0)) != 0)
return (ret);
}
++rp->re_last;
++sp;
}
rp->re_cmap = sp;
return (0);
}
/*
* __ram_add --
* Add records into the tree.
*/
static int
__ram_add(dbc, recnop, data, flags, bi_flags)
DBC *dbc;
db_recno_t *recnop;
DBT *data;
u_int32_t flags, bi_flags;
{
BKEYDATA *bk;
CURSOR *cp;
DB *dbp;
PAGE *h;
db_indx_t indx;
int exact, isdeleted, ret, stack;
dbp = dbc->dbp;
cp = dbc->internal;
retry: /* Find the slot for insertion. */
if ((ret = __bam_rsearch(dbc, recnop,
S_INSERT | (flags == DB_APPEND ? S_APPEND : 0), 1, &exact)) != 0)
return (ret);
h = cp->csp->page;
indx = cp->csp->indx;
stack = 1;
/*
* If re-numbering records, the on-page deleted flag means this record
* was implicitly created. If not re-numbering records, the on-page
* deleted flag means this record was implicitly created, or, it was
* deleted at some time.
*
* If DB_NOOVERWRITE is set and the item already exists in the tree,
* return an error unless the item was either marked for deletion or
* only implicitly created.
*/
isdeleted = 0;
if (exact) {
bk = GET_BKEYDATA(h, indx);
if (B_DISSET(bk->type))
isdeleted = 1;
else
if (flags == DB_NOOVERWRITE) {
ret = DB_KEYEXIST;
goto err;
}
}
/*
* Select the arguments for __bam_iitem() and do the insert. If the
* key is an exact match, or we're replacing the data item with a
* new data item, replace the current item. If the key isn't an exact
* match, we're inserting a new key/data pair, before the search
* location.
*/
switch (ret = __bam_iitem(dbc,
&h, &indx, NULL, data, exact ? DB_CURRENT : DB_BEFORE, bi_flags)) {
case 0:
/*
* Don't adjust anything.
*
* If we inserted a record, no cursors need adjusting because
* the only new record it's possible to insert is at the very
* end of the tree. The necessary adjustments to the internal
* page counts were made by __bam_iitem().
*
* If we overwrote a record, no cursors need adjusting because
* future DBcursor->get calls will simply return the underlying
* record (there's no adjustment made for the DB_CURRENT flag
* when a cursor get operation immediately follows a cursor
* delete operation, and the normal adjustment for the DB_NEXT
* flag is still correct).
*/
break;
case DB_NEEDSPLIT:
/* Discard the stack of pages and split the page. */
(void)__bam_stkrel(dbc, 0);
stack = 0;
if ((ret = __bam_split(dbc, recnop)) != 0)
goto err;
goto retry;
/* NOTREACHED */
default:
goto err;
}
err: if (stack)
__bam_stkrel(dbc, 0);
return (ret);
}