bt_recno.c
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上传日期:2022-05-23
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文件大小:34k
- /*-
- * See the file LICENSE for redistribution information.
- *
- * Copyright (c) 1997-2002
- * Sleepycat Software. All rights reserved.
- */
- #include "db_config.h"
- #ifndef lint
- static const char revid[] = "$Id: bt_recno.c,v 11.106 2002/08/16 04:56:30 ubell Exp $";
- #endif /* not lint */
- #ifndef NO_SYSTEM_INCLUDES
- #include <sys/types.h>
- #include <limits.h>
- #include <stdio.h>
- #include <string.h>
- #endif
- #include "db_int.h"
- #include "dbinc/db_page.h"
- #include "dbinc/btree.h"
- #include "dbinc/db_shash.h"
- #include "dbinc/lock.h"
- static int __ram_add __P((DBC *, db_recno_t *, DBT *, u_int32_t, u_int32_t));
- static int __ram_source __P((DB *));
- static int __ram_sread __P((DBC *, db_recno_t));
- static int __ram_update __P((DBC *, db_recno_t, int));
- /*
- * 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(cp) {
- if (F_ISSET(cp, C_RENUMBER))
- F_SET(cp, C_DELETED);
- }
- #define CD_CLR(cp) {
- if (F_ISSET(cp, C_RENUMBER)) {
- F_CLR(cp, C_DELETED);
- cp->order = INVALID_ORDER;
- }
- }
- #define CD_ISSET(cp)
- (F_ISSET(cp, C_RENUMBER) && F_ISSET(cp, C_DELETED))
- /*
- * Macros for comparing the ordering of two cursors.
- * cp1 comes before cp2 iff one of the following holds:
- * cp1's recno is less than cp2's recno
- * recnos are equal, both deleted, and cp1's order is less than cp2's
- * recnos are equal, cp1 deleted, and cp2 not deleted
- */
- #define C_LESSTHAN(cp1, cp2)
- (((cp1)->recno < (cp2)->recno) ||
- (((cp1)->recno == (cp2)->recno) &&
- ((CD_ISSET((cp1)) && CD_ISSET((cp2)) && (cp1)->order < (cp2)->order) ||
- (CD_ISSET((cp1)) && !CD_ISSET((cp2))))))
- /*
- * cp1 is equal to cp2 iff their recnos and delete flags are identical,
- * and if the delete flag is set their orders are also identical.
- */
- #define C_EQUAL(cp1, cp2)
- ((cp1)->recno == (cp2)->recno && CD_ISSET((cp1)) == CD_ISSET((cp2)) &&
- (!CD_ISSET((cp1)) || (cp1)->order == (cp2)->order))
- /*
- * Do we need to log the current cursor adjustment?
- */
- #define CURADJ_LOG(dbc)
- (DBC_LOGGING((dbc)) && (dbc)->txn != NULL && (dbc)->txn->parent != NULL)
- /*
- * After a search, copy the found page into the cursor, discarding any
- * currently held lock.
- */
- #define STACK_TO_CURSOR(cp) {
- (cp)->page = (cp)->csp->page;
- (cp)->pgno = (cp)->csp->page->pgno;
- (cp)->indx = (cp)->csp->indx;
- (void)__TLPUT(dbc, (cp)->lock);
- (cp)->lock = (cp)->csp->lock;
- (cp)->lock_mode = (cp)->csp->lock_mode;
- }
- /*
- * __ram_open --
- * Recno open function.
- *
- * PUBLIC: int __ram_open __P((DB *,
- * PUBLIC: DB_TXN *, const char *, db_pgno_t, u_int32_t));
- */
- int
- __ram_open(dbp, txn, name, base_pgno, flags)
- DB *dbp;
- DB_TXN *txn;
- const char *name;
- db_pgno_t base_pgno;
- u_int32_t flags;
- {
- BTREE *t;
- DBC *dbc;
- int ret, t_ret;
- COMPQUIET(name, NULL);
- t = dbp->bt_internal;
- /* Initialize the remaining fields/methods of the DB. */
- dbp->stat = __bam_stat;
- /* Start up the tree. */
- if ((ret = __bam_read_root(dbp, txn, base_pgno, flags)) != 0)
- return (ret);
- /*
- * 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 (t->re_source != NULL && (ret = __ram_source(dbp)) != 0)
- return (ret);
- /* If we're snapshotting an underlying source file, do it now. */
- if (F_ISSET(dbp, DB_AM_SNAPSHOT)) {
- /* Allocate a cursor. */
- if ((ret = dbp->cursor(dbp, NULL, &dbc, 0)) != 0)
- return (ret);
- /* 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;
- }
- return (ret);
- }
- /*
- * __ram_append --
- * Recno append function.
- *
- * PUBLIC: int __ram_append __P((DBC *, DBT *, DBT *));
- */
- int
- __ram_append(dbc, key, data)
- DBC *dbc;
- DBT *key, *data;
- {
- BTREE_CURSOR *cp;
- int ret;
- cp = (BTREE_CURSOR *)dbc->internal;
- /*
- * Make sure we've read in all of the backing source file. If
- * we found the record or it simply didn't exist, add the
- * user's record.
- */
- ret = __ram_update(dbc, DB_MAX_RECORDS, 0);
- if (ret == 0 || ret == DB_NOTFOUND)
- ret = __ram_add(dbc, &cp->recno, data, DB_APPEND, 0);
- /* Return the record number. */
- if (ret == 0)
- ret = __db_retcopy(dbc->dbp->dbenv, key, &cp->recno,
- sizeof(cp->recno), &dbc->rkey->data, &dbc->rkey->ulen);
- return (ret);
- }
- /*
- * __ram_c_del --
- * Recno cursor->c_del function.
- *
- * PUBLIC: int __ram_c_del __P((DBC *));
- */
- int
- __ram_c_del(dbc)
- DBC *dbc;
- {
- BKEYDATA bk;
- BTREE *t;
- BTREE_CURSOR *cp;
- DB *dbp;
- DB_LSN lsn;
- DBT hdr, data;
- EPG *epg;
- int exact, ret, stack;
- dbp = dbc->dbp;
- cp = (BTREE_CURSOR *)dbc->internal;
- t = dbp->bt_internal;
- stack = 0;
- /*
- * The semantics of cursors during delete are as follows: in
- * non-renumbering recnos, 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.
- *
- * In renumbering recnos, cursors which represent deleted items
- * are flagged with the C_DELETED flag, and it is an error to
- * call c_del a second time without an intervening cursor motion.
- */
- if (CD_ISSET(cp))
- return (DB_KEYEMPTY);
- /* 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;
- /* Copy the page into the cursor. */
- STACK_TO_CURSOR(cp);
- /*
- * 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(dbp, cp->page, cp->indx)->type)) {
- ret = DB_KEYEMPTY;
- goto err;
- }
- if (F_ISSET(cp, C_RENUMBER)) {
- /* Delete the item, adjust the counts, adjust the cursors. */
- if ((ret = __bam_ditem(dbc, cp->page, cp->indx)) != 0)
- goto err;
- __bam_adjust(dbc, -1);
- if (__ram_ca(dbc, CA_DELETE) > 0 &&
- CURADJ_LOG(dbc) && (ret = __bam_rcuradj_log(dbp, dbc->txn,
- &lsn, 0, CA_DELETE, cp->root, cp->recno, cp->order)) != 0)
- goto err;
- /*
- * If the page is empty, delete it.
- *
- * We never delete a root page. First, root pages of primary
- * databases never go away, recno or otherwise. However, if
- * it's the root page of an off-page duplicates database, then
- * it can be deleted. We don't delete it here because we have
- * no way of telling the primary database page holder (e.g.,
- * the hash access method) that its page element should cleaned
- * up because the underlying tree is gone. So, we keep the page
- * around until the last cursor referencing the empty tree is
- * are closed, and then clean it up.
- */
- if (NUM_ENT(cp->page) == 0 && PGNO(cp->page) != cp->root) {
- /*
- * We already have a locked stack of pages. However,
- * there are likely entries in the stack that aren't
- * going to be emptied by removing the single reference
- * to the emptied page (or one of its parents).
- */
- for (epg = cp->csp; epg >= cp->sp; --epg)
- if (NUM_ENT(epg->page) > 1)
- break;
- /*
- * We want to delete a single item out of the last page
- * that we're not deleting.
- */
- ret = __bam_dpages(dbc, epg);
- /*
- * Regardless of the return from __bam_dpages, it will
- * discard our stack and pinned page.
- */
- stack = 0;
- cp->page = NULL;
- }
- } else {
- /* Use a delete/put pair to replace the record with a marker. */
- if ((ret = __bam_ditem(dbc, cp->page, cp->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 = (void *)"";
- data.size = 0;
- if ((ret = __db_pitem(dbc,
- cp->page, cp->indx, BKEYDATA_SIZE(0), &hdr, &data)) != 0)
- goto err;
- }
- t->re_modified = 1;
- err: if (stack)
- __bam_stkrel(dbc, STK_CLRDBC);
- return (ret);
- }
- /*
- * __ram_c_get --
- * Recno cursor->c_get function.
- *
- * PUBLIC: int __ram_c_get
- * PUBLIC: __P((DBC *, DBT *, DBT *, u_int32_t, db_pgno_t *));
- */
- int
- __ram_c_get(dbc, key, data, flags, pgnop)
- DBC *dbc;
- DBT *key, *data;
- u_int32_t flags;
- db_pgno_t *pgnop;
- {
- BTREE_CURSOR *cp;
- DB *dbp;
- int cmp, exact, ret;
- COMPQUIET(pgnop, NULL);
- dbp = dbc->dbp;
- cp = (BTREE_CURSOR *)dbc->internal;
- LF_CLR(DB_MULTIPLE|DB_MULTIPLE_KEY);
- retry: switch (flags) {
- case DB_CURRENT:
- /*
- * If we're using mutable records and the deleted flag is
- * set, the cursor is pointing at a nonexistent record;
- * return an error.
- */
- if (CD_ISSET(cp))
- return (DB_KEYEMPTY);
- break;
- case DB_NEXT_DUP:
- /*
- * If we're not in an off-page dup set, we know there's no
- * next duplicate since recnos don't have them. If we
- * are in an off-page dup set, the next item assuredly is
- * a dup, so we set flags to DB_NEXT and keep going.
- */
- if (!F_ISSET(dbc, DBC_OPD))
- return (DB_NOTFOUND);
- /* FALLTHROUGH */
- case DB_NEXT_NODUP:
- /*
- * Recno databases don't have duplicates, set flags to DB_NEXT
- * and keep going.
- */
- /* FALLTHROUGH */
- case DB_NEXT:
- flags = 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(cp))
- break;
- if (cp->recno != RECNO_OOB) {
- ++cp->recno;
- break;
- }
- /* FALLTHROUGH */
- case DB_FIRST:
- flags = DB_NEXT;
- cp->recno = 1;
- break;
- case DB_PREV_NODUP:
- /*
- * Recno databases don't have duplicates, set flags to DB_PREV
- * and keep going.
- */
- /* FALLTHROUGH */
- case DB_PREV:
- flags = 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_GET_BOTHC:
- /*
- * If we're doing a join and these are offpage dups,
- * we want to keep searching forward from after the
- * current cursor position. Increment the recno by 1,
- * then proceed as for a DB_SET.
- *
- * Otherwise, we know there are no additional matching
- * data, as recnos don't have dups. return DB_NOTFOUND.
- */
- if (F_ISSET(dbc, DBC_OPD)) {
- cp->recno++;
- break;
- }
- ret = DB_NOTFOUND;
- goto err;
- /* NOTREACHED */
- case DB_GET_BOTH:
- case DB_GET_BOTH_RANGE:
- /*
- * If we're searching a set of off-page dups, we start
- * a new linear search from the first record. Otherwise,
- * we compare the single data item associated with the
- * requested record for a match.
- */
- if (F_ISSET(dbc, DBC_OPD)) {
- cp->recno = 1;
- break;
- }
- /* FALLTHROUGH */
- case DB_SET:
- case DB_SET_RANGE:
- if ((ret = __ram_getno(dbc, key, &cp->recno, 0)) != 0)
- goto err;
- break;
- default:
- ret = __db_unknown_flag(dbp->dbenv, "__ram_c_get", flags);
- goto err;
- }
- /*
- * For DB_PREV, DB_LAST, DB_SET and DB_SET_RANGE, we have already
- * called __ram_update() to make sure sufficient records have been
- * read from the backing source file. Do it now for DB_CURRENT (if
- * the current record was deleted we may need more records from the
- * backing file for a DB_CURRENT operation), DB_FIRST and DB_NEXT.
- * (We don't have to test for flags == DB_FIRST, because the switch
- * statement above re-set flags to DB_NEXT in that case.)
- */
- if ((flags == DB_NEXT || flags == DB_CURRENT) && ((ret =
- __ram_update(dbc, cp->recno, 0)) != 0) && ret != DB_NOTFOUND)
- goto err;
- for (;; ++cp->recno) {
- /* 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;
- if (!exact) {
- ret = DB_NOTFOUND;
- goto err;
- }
- /* Copy the page into the cursor. */
- STACK_TO_CURSOR(cp);
- /*
- * 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 or
- * walking through off-page duplicates, and fail if they were
- * requested explicitly by the application.
- */
- if (B_DISSET(GET_BKEYDATA(dbp, cp->page, cp->indx)->type))
- switch (flags) {
- case DB_NEXT:
- case DB_PREV:
- (void)__bam_stkrel(dbc, STK_CLRDBC);
- goto retry;
- case DB_GET_BOTH:
- case DB_GET_BOTH_RANGE:
- /*
- * If we're an OPD tree, we don't care about
- * matching a record number on a DB_GET_BOTH
- * -- everything belongs to the same tree. A
- * normal recno should give up and return
- * DB_NOTFOUND if the matching recno is deleted.
- */
- if (F_ISSET(dbc, DBC_OPD)) {
- (void)__bam_stkrel(dbc, STK_CLRDBC);
- continue;
- }
- ret = DB_NOTFOUND;
- goto err;
- default:
- ret = DB_KEYEMPTY;
- goto err;
- }
- if (flags == DB_GET_BOTH ||
- flags == DB_GET_BOTHC || flags == DB_GET_BOTH_RANGE) {
- if ((ret = __bam_cmp(dbp, data,
- cp->page, cp->indx, __bam_defcmp, &cmp)) != 0)
- return (ret);
- if (cmp == 0)
- break;
- if (!F_ISSET(dbc, DBC_OPD)) {
- ret = DB_NOTFOUND;
- goto err;
- }
- (void)__bam_stkrel(dbc, STK_CLRDBC);
- } else
- break;
- }
- /* Return the key if the user didn't give us one. */
- if (!F_ISSET(dbc, DBC_OPD)) {
- if (flags != DB_GET_BOTH && flags != DB_GET_BOTH_RANGE &&
- flags != DB_SET && flags != DB_SET_RANGE)
- ret = __db_retcopy(dbp->dbenv,
- key, &cp->recno, sizeof(cp->recno),
- &dbc->rkey->data, &dbc->rkey->ulen);
- F_SET(key, DB_DBT_ISSET);
- }
- /* The cursor was reset, no further delete adjustment is necessary. */
- err: CD_CLR(cp);
- return (ret);
- }
- /*
- * __ram_c_put --
- * Recno cursor->c_put function.
- *
- * PUBLIC: int __ram_c_put __P((DBC *, DBT *, DBT *, u_int32_t, db_pgno_t *));
- */
- int
- __ram_c_put(dbc, key, data, flags, pgnop)
- DBC *dbc;
- DBT *key, *data;
- u_int32_t flags;
- db_pgno_t *pgnop;
- {
- BTREE_CURSOR *cp;
- DB *dbp;
- DB_LSN lsn;
- int exact, nc, ret, t_ret;
- u_int32_t iiflags;
- void *arg;
- COMPQUIET(pgnop, NULL);
- dbp = dbc->dbp;
- cp = (BTREE_CURSOR *)dbc->internal;
- /*
- * DB_KEYFIRST and DB_KEYLAST mean different things if they're
- * used in an off-page duplicate tree. If we're an off-page
- * duplicate tree, they really mean "put at the beginning of the
- * tree" and "put at the end of the tree" respectively, so translate
- * them to something else.
- */
- if (F_ISSET(dbc, DBC_OPD))
- switch (flags) {
- case DB_KEYFIRST:
- cp->recno = 1;
- flags = DB_BEFORE;
- break;
- case DB_KEYLAST:
- if ((ret = __ram_add(dbc,
- &cp->recno, data, DB_APPEND, 0)) != 0)
- return (ret);
- if (CURADJ_LOG(dbc) &&
- (ret = __bam_rcuradj_log(dbp, dbc->txn, &lsn, 0,
- CA_ICURRENT, cp->root, cp->recno, cp->order)))
- return (ret);
- return (0);
- }
- /*
- * Handle normal DB_KEYFIRST/DB_KEYLAST; for a recno, which has
- * no duplicates, these are identical and mean "put the given
- * datum at the given recno".
- *
- * Note that the code here used to be in __ram_put; now, we
- * go through the access-method-common __db_put function, which
- * handles DB_NOOVERWRITE, so we and __ram_add don't have to.
- */
- if (flags == DB_KEYFIRST || flags == DB_KEYLAST) {
- ret = __ram_getno(dbc, key, &cp->recno, 1);
- if (ret == 0 || ret == DB_NOTFOUND)
- ret = __ram_add(dbc, &cp->recno, data, 0, 0);
- return (ret);
- }
- /*
- * If we're putting with a cursor that's marked C_DELETED, we need to
- * take special care; the cursor doesn't "really" reference the item
- * corresponding to its current recno, but instead is "between" that
- * record and the current one. Translate the actual insert into
- * DB_BEFORE, and let the __ram_ca work out the gory details of what
- * should wind up pointing where.
- */
- if (CD_ISSET(cp))
- iiflags = DB_BEFORE;
- else
- iiflags = flags;
- split: if ((ret = __bam_rsearch(dbc, &cp->recno, S_INSERT, 1, &exact)) != 0)
- goto err;
- /*
- * An inexact match is okay; it just means we're one record past the
- * end, which is reasonable if we're marked deleted.
- */
- DB_ASSERT(exact || CD_ISSET(cp));
- /* Copy the page into the cursor. */
- STACK_TO_CURSOR(cp);
- ret = __bam_iitem(dbc, key, data, iiflags, 0);
- t_ret = __bam_stkrel(dbc, STK_CLRDBC);
- if (t_ret != 0 && (ret == 0 || ret == DB_NEEDSPLIT))
- ret = t_ret;
- else if (ret == DB_NEEDSPLIT) {
- arg = &cp->recno;
- if ((ret = __bam_split(dbc, arg, NULL)) != 0)
- goto err;
- goto split;
- }
- if (ret != 0)
- goto err;
- switch (flags) { /* Adjust the cursors. */
- case DB_AFTER:
- nc = __ram_ca(dbc, CA_IAFTER);
- /*
- * We only need to adjust this cursor forward if we truly added
- * the item after the current recno, rather than remapping it
- * to DB_BEFORE.
- */
- if (iiflags == DB_AFTER)
- ++cp->recno;
- /* Only log if __ram_ca found any relevant cursors. */
- if (nc > 0 && CURADJ_LOG(dbc) &&
- (ret = __bam_rcuradj_log(dbp, dbc->txn, &lsn, 0, CA_IAFTER,
- cp->root, cp->recno, cp->order)) != 0)
- goto err;
- break;
- case DB_BEFORE:
- nc = __ram_ca(dbc, CA_IBEFORE);
- --cp->recno;
- /* Only log if __ram_ca found any relevant cursors. */
- if (nc > 0 && CURADJ_LOG(dbc) &&
- (ret = __bam_rcuradj_log(dbp, dbc->txn, &lsn, 0, CA_IBEFORE,
- cp->root, cp->recno, cp->order)) != 0)
- goto err;
- break;
- case DB_CURRENT:
- /*
- * We only need to do an adjustment if we actually
- * added an item, which we only would have done if the
- * cursor was marked deleted.
- *
- * Only log if __ram_ca found any relevant cursors.
- */
- if (CD_ISSET(cp) && __ram_ca(dbc, CA_ICURRENT) > 0 &&
- CURADJ_LOG(dbc) &&
- (ret = __bam_rcuradj_log(dbp, dbc->txn, &lsn, 0,
- CA_ICURRENT, cp->root, cp->recno, cp->order)) != 0)
- goto err;
- break;
- }
- /* Return the key if we've created a new record. */
- if (!F_ISSET(dbc, DBC_OPD) && (flags == DB_AFTER || flags == DB_BEFORE))
- ret = __db_retcopy(dbp->dbenv, key, &cp->recno,
- sizeof(cp->recno), &dbc->rkey->data, &dbc->rkey->ulen);
- /* The cursor was reset, no further delete adjustment is necessary. */
- err: CD_CLR(cp);
- return (ret);
- }
- /*
- * __ram_ca --
- * Adjust cursors. Returns the number of relevant cursors.
- *
- * PUBLIC: int __ram_ca __P((DBC *, ca_recno_arg));
- */
- int
- __ram_ca(dbc_arg, op)
- DBC *dbc_arg;
- ca_recno_arg op;
- {
- BTREE_CURSOR *cp, *cp_arg;
- DB *dbp, *ldbp;
- DB_ENV *dbenv;
- DBC *dbc;
- db_recno_t recno;
- int adjusted, found;
- u_int32_t order;
- dbp = dbc_arg->dbp;
- dbenv = dbp->dbenv;
- cp_arg = (BTREE_CURSOR *)dbc_arg->internal;
- recno = cp_arg->recno;
- found = 0;
- /*
- * It only makes sense to adjust cursors if we're a renumbering
- * recno; we should only be called if this is one.
- */
- DB_ASSERT(F_ISSET(cp_arg, C_RENUMBER));
- MUTEX_THREAD_LOCK(dbenv, dbenv->dblist_mutexp);
- /*
- * Adjust the cursors. See the comment in __bam_ca_delete().
- */
- /*
- * If we're doing a delete, we need to find the highest
- * order of any cursor currently pointing at this item,
- * so we can assign a higher order to the newly deleted
- * cursor. Unfortunately, this requires a second pass through
- * the cursor list.
- */
- if (op == CA_DELETE) {
- order = 1;
- for (ldbp = __dblist_get(dbenv, dbp->adj_fileid);
- ldbp != NULL && ldbp->adj_fileid == dbp->adj_fileid;
- ldbp = LIST_NEXT(ldbp, dblistlinks)) {
- MUTEX_THREAD_LOCK(dbenv, dbp->mutexp);
- for (dbc = TAILQ_FIRST(&ldbp->active_queue);
- dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
- cp = (BTREE_CURSOR *)dbc->internal;
- if (cp_arg->root == cp->root &&
- recno == cp->recno && CD_ISSET(cp) &&
- order <= cp->order)
- order = cp->order + 1;
- }
- MUTEX_THREAD_UNLOCK(dbenv, dbp->mutexp);
- }
- } else
- order = INVALID_ORDER;
- /* Now go through and do the actual adjustments. */
- for (ldbp = __dblist_get(dbenv, dbp->adj_fileid);
- ldbp != NULL && ldbp->adj_fileid == dbp->adj_fileid;
- ldbp = LIST_NEXT(ldbp, dblistlinks)) {
- MUTEX_THREAD_LOCK(dbenv, dbp->mutexp);
- for (dbc = TAILQ_FIRST(&ldbp->active_queue);
- dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
- cp = (BTREE_CURSOR *)dbc->internal;
- if (cp_arg->root != cp->root)
- continue;
- ++found;
- adjusted = 0;
- switch (op) {
- case CA_DELETE:
- if (recno < cp->recno) {
- --cp->recno;
- /*
- * If the adjustment made them equal,
- * we have to merge the orders.
- */
- if (recno == cp->recno && CD_ISSET(cp))
- cp->order += order;
- } else if (recno == cp->recno &&
- !CD_ISSET(cp)) {
- CD_SET(cp);
- cp->order = order;
- }
- break;
- case CA_IBEFORE:
- /*
- * IBEFORE is just like IAFTER, except that we
- * adjust cursors on the current record too.
- */
- if (C_EQUAL(cp_arg, cp)) {
- ++cp->recno;
- adjusted = 1;
- }
- goto iafter;
- case CA_ICURRENT:
- /*
- * If the original cursor wasn't deleted, we
- * just did a replacement and so there's no
- * need to adjust anything--we shouldn't have
- * gotten this far. Otherwise, we behave
- * much like an IAFTER, except that all
- * cursors pointing to the current item get
- * marked undeleted and point to the new
- * item.
- */
- DB_ASSERT(CD_ISSET(cp_arg));
- if (C_EQUAL(cp_arg, cp)) {
- CD_CLR(cp);
- break;
- }
- /* FALLTHROUGH */
- case CA_IAFTER:
- iafter: if (!adjusted && C_LESSTHAN(cp_arg, cp)) {
- ++cp->recno;
- adjusted = 1;
- }
- if (recno == cp->recno && adjusted)
- /*
- * If we've moved this cursor's recno,
- * split its order number--i.e.,
- * decrement it by enough so that
- * the lowest cursor moved has order 1.
- * cp_arg->order is the split point,
- * so decrement by one less than that.
- */
- cp->order -= (cp_arg->order - 1);
- break;
- }
- }
- MUTEX_THREAD_UNLOCK(dbp->dbenv, dbp->mutexp);
- }
- MUTEX_THREAD_UNLOCK(dbenv, dbenv->dblist_mutexp);
- return (found);
- }
- /*
- * __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 (dbc->dbtype == 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;
- DBT *rdata;
- db_recno_t nrecs;
- int ret;
- dbp = dbc->dbp;
- t = dbp->bt_internal;
- /*
- * If we can't create records and we've read the entire backing input
- * file, we're done.
- */
- if (!can_create && t->re_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 (!t->re_eof && recno > nrecs) {
- if ((ret = __ram_sread(dbc, recno)) != 0 && ret != DB_NOTFOUND)
- 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);
- rdata = &dbc->my_rdata;
- rdata->flags = 0;
- rdata->size = 0;
- while (recno > ++nrecs)
- if ((ret = __ram_add(dbc,
- &nrecs, rdata, 0, BI_DELETED)) != 0)
- return (ret);
- return (0);
- }
- /*
- * __ram_source --
- * Load information about the backing file.
- */
- static int
- __ram_source(dbp)
- DB *dbp;
- {
- BTREE *t;
- char *source;
- int ret;
- t = dbp->bt_internal;
- /* Find the real name, and swap out the one we had before. */
- if ((ret = __db_appname(dbp->dbenv,
- DB_APP_DATA, t->re_source, 0, NULL, &source)) != 0)
- return (ret);
- __os_free(dbp->dbenv, t->re_source);
- t->re_source = source;
- /*
- * !!!
- * It's possible that the backing source file is read-only. We don't
- * much care other than we'll complain if there are any modifications
- * when it comes time to write the database back to the source.
- */
- if ((t->re_fp = fopen(t->re_source, "r")) == NULL) {
- ret = errno;
- __db_err(dbp->dbenv, "%s: %s", t->re_source, db_strerror(ret));
- return (ret);
- }
- t->re_eof = 0;
- return (0);
- }
- /*
- * __ram_writeback --
- * Rewrite the backing file.
- *
- * PUBLIC: int __ram_writeback __P((DB *));
- */
- int
- __ram_writeback(dbp)
- DB *dbp;
- {
- BTREE *t;
- DB_ENV *dbenv;
- DBC *dbc;
- DBT key, data;
- FILE *fp;
- db_recno_t keyno;
- int ret, t_ret;
- u_int8_t delim, *pad;
- t = dbp->bt_internal;
- dbenv = dbp->dbenv;
- fp = NULL;
- pad = NULL;
- /* If the file wasn't modified, we're done. */
- if (!t->re_modified)
- return (0);
- /* If there's no backing source file, we're done. */
- if (t->re_source == NULL) {
- t->re_modified = 0;
- return (0);
- }
- /* Allocate a cursor. */
- if ((ret = dbp->cursor(dbp, NULL, &dbc, 0)) != 0)
- return (ret);
- /*
- * 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 as DB->open is transaction protected. 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.
- *
- * XXX
- * This could be made to work now that we have transactions protecting
- * file operations. Margo has specifically asked for the privilege of
- * doing this work.
- */
- if ((ret =
- __ram_update(dbc, DB_MAX_RECORDS, 0)) != 0 && ret != DB_NOTFOUND)
- return (ret);
- /*
- * Close any existing file handle and re-open the file, truncating it.
- */
- if (t->re_fp != NULL) {
- if (fclose(t->re_fp) != 0) {
- ret = errno;
- goto err;
- }
- t->re_fp = NULL;
- }
- if ((fp = fopen(t->re_source, "w")) == NULL) {
- ret = errno;
- __db_err(dbenv, "%s: %s", t->re_source, db_strerror(ret));
- goto err;
- }
- /*
- * 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. The DB handle may
- * be threaded, so allocate memory as we go.
- */
- memset(&key, 0, sizeof(key));
- key.size = sizeof(db_recno_t);
- key.data = &keyno;
- memset(&data, 0, sizeof(data));
- F_SET(&data, DB_DBT_REALLOC);
- /*
- * We'll need the delimiter if we're doing variable-length records,
- * and the pad character if we're doing fixed-length records.
- */
- delim = t->re_delim;
- if (F_ISSET(dbp, DB_AM_FIXEDLEN)) {
- if ((ret = __os_malloc(dbenv, t->re_len, &pad)) != 0)
- goto err;
- memset(pad, t->re_pad, t->re_len);
- }
- for (keyno = 1;; ++keyno) {
- switch (ret = dbp->get(dbp, NULL, &key, &data, 0)) {
- case 0:
- if (data.size != 0 && (u_int32_t)fwrite(
- data.data, 1, data.size, fp) != data.size)
- goto write_err;
- break;
- case DB_KEYEMPTY:
- if (F_ISSET(dbp, DB_AM_FIXEDLEN) &&
- (u_int32_t)fwrite(pad, 1, t->re_len, fp) !=
- t->re_len)
- goto write_err;
- break;
- case DB_NOTFOUND:
- ret = 0;
- goto done;
- default:
- goto err;
- }
- if (!F_ISSET(dbp, DB_AM_FIXEDLEN) &&
- fwrite(&delim, 1, 1, fp) != 1) {
- write_err: ret = errno;
- __db_err(dbp->dbenv,
- "%s: write failed to backing file: %s",
- t->re_source, strerror(ret));
- goto err;
- }
- }
- err:
- done: /* Close the file descriptor. */
- if (fp != NULL && fclose(fp) != 0) {
- if (ret == 0)
- ret = errno;
- __db_err(dbenv, "%s: %s", t->re_source, db_strerror(errno));
- }
- /* Discard the cursor. */
- if ((t_ret = dbc->c_close(dbc)) != 0 && ret == 0)
- ret = t_ret;
- /* Discard memory allocated to hold the data items. */
- if (data.data != NULL)
- __os_ufree(dbenv, data.data);
- if (pad != NULL)
- __os_free(dbenv, pad);
- if (ret == 0)
- t->re_modified = 0;
- return (ret);
- }
- /*
- * __ram_sread --
- * Read records from a source file.
- */
- static int
- __ram_sread(dbc, top)
- DBC *dbc;
- db_recno_t top;
- {
- BTREE *t;
- DB *dbp;
- DBT data, *rdata;
- db_recno_t recno;
- size_t len;
- int ch, ret, was_modified;
- t = dbc->dbp->bt_internal;
- dbp = dbc->dbp;
- was_modified = t->re_modified;
- if ((ret = __bam_nrecs(dbc, &recno)) != 0)
- return (ret);
- /*
- * Use the record key return memory, it's only a short-term use.
- * The record data return memory is used by __bam_iitem, which
- * we'll indirectly call, so use the key so as not to collide.
- */
- len = F_ISSET(dbp, DB_AM_FIXEDLEN) ? t->re_len : 256;
- rdata = &dbc->my_rkey;
- if (rdata->ulen < len) {
- if ((ret = __os_realloc(
- dbp->dbenv, len, &rdata->data)) != 0) {
- rdata->ulen = 0;
- rdata->data = NULL;
- return (ret);
- }
- rdata->ulen = (u_int32_t)len;
- }
- memset(&data, 0, sizeof(data));
- while (recno < top) {
- data.data = rdata->data;
- data.size = 0;
- if (F_ISSET(dbp, DB_AM_FIXEDLEN))
- for (len = t->re_len; len > 0; --len) {
- if ((ch = getc(t->re_fp)) == EOF) {
- if (data.size == 0)
- goto eof;
- break;
- }
- ((u_int8_t *)data.data)[data.size++] = ch;
- }
- else
- for (;;) {
- if ((ch = getc(t->re_fp)) == EOF) {
- if (data.size == 0)
- goto eof;
- break;
- }
- if (ch == t->re_delim)
- break;
- ((u_int8_t *)data.data)[data.size++] = ch;
- if (data.size == rdata->ulen) {
- if ((ret = __os_realloc(dbp->dbenv,
- rdata->ulen *= 2,
- &rdata->data)) != 0) {
- rdata->ulen = 0;
- rdata->data = NULL;
- return (ret);
- } else
- data.data = rdata->data;
- }
- }
- /*
- * 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 (t->re_last >= recno) {
- ++recno;
- if ((ret = __ram_add(dbc, &recno, &data, 0, 0)) != 0)
- goto err;
- }
- ++t->re_last;
- }
- if (0) {
- eof: t->re_eof = 1;
- ret = DB_NOTFOUND;
- }
- err: if (!was_modified)
- t->re_modified = 0;
- return (ret);
- }
- /*
- * __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;
- {
- BTREE_CURSOR *cp;
- int exact, ret, stack;
- cp = (BTREE_CURSOR *)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);
- stack = 1;
- /* Copy the page into the cursor. */
- STACK_TO_CURSOR(cp);
- /*
- * The application may modify the data based on the selected record
- * number.
- */
- if (flags == DB_APPEND && dbc->dbp->db_append_recno != NULL &&
- (ret = dbc->dbp->db_append_recno(dbc->dbp, data, *recnop)) != 0)
- 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,
- 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, STK_CLRDBC);
- stack = 0;
- if ((ret = __bam_split(dbc, recnop, NULL)) != 0)
- goto err;
- goto retry;
- /* NOTREACHED */
- default:
- goto err;
- }
- err: if (stack)
- __bam_stkrel(dbc, STK_CLRDBC);
- return (ret);
- }