diff options
Diffstat (limited to 'debian/htdig/htdig-3.2.0b6/db/bt_put.c')
| -rw-r--r-- | debian/htdig/htdig-3.2.0b6/db/bt_put.c | 896 |
1 files changed, 896 insertions, 0 deletions
diff --git a/debian/htdig/htdig-3.2.0b6/db/bt_put.c b/debian/htdig/htdig-3.2.0b6/db/bt_put.c new file mode 100644 index 00000000..c6039529 --- /dev/null +++ b/debian/htdig/htdig-3.2.0b6/db/bt_put.c @@ -0,0 +1,896 @@ +/*- + * See the file LICENSE for redistribution information. + * + * Copyright (c) 1996, 1997, 1998, 1999 + * Sleepycat Software. All rights reserved. + */ +/* + * Copyright (c) 1990, 1993, 1994, 1995, 1996 + * Keith Bostic. All rights reserved. + */ +/* + * Copyright (c) 1990, 1993, 1994, 1995 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Mike Olson. + * + * 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[] = "@(#)bt_put.c 11.20 (Sleepycat) 10/28/99"; +#endif /* not lint */ + +#ifndef NO_SYSTEM_INCLUDES +#include <sys/types.h> + +#include <errno.h> +#include <string.h> +#endif + +#include "db_int.h" +#include "db_page.h" +#include "btree.h" + +static int CDB___bam_ndup __P((DBC *, PAGE *, u_int32_t)); +static int CDB___bam_ovput __P((DBC *, PAGE *, u_int32_t, DBT *)); + +/* + * CDB___bam_iitem -- + * Insert an item into the tree. + * + * PUBLIC: int CDB___bam_iitem __P((DBC *, + * PUBLIC: PAGE **, db_indx_t *, DBT *, DBT *, u_int32_t, u_int32_t)); + */ +int +CDB___bam_iitem(dbc, hp, indxp, key, data, op, flags) + DBC *dbc; + PAGE **hp; + db_indx_t *indxp; + DBT *key, *data; + u_int32_t op, flags; +{ + BKEYDATA *bk; + BTREE *t; + BTREE_CURSOR *cp; + DB *dbp; + DBT tdbt; + PAGE *h; + db_indx_t indx; + db_pgno_t pgno; + u_int32_t data_size, have_bytes, need_bytes, needed; + int bigkey, bigdata, dupadjust, padrec, replace, ret, was_deleted; + + COMPQUIET(bk, NULL); + + dbp = dbc->dbp; + t = dbp->bt_internal; + h = *hp; + indx = *indxp; + dupadjust = replace = was_deleted = 0; + + /* + * Fixed-length records with partial puts: it's an error to specify + * anything other simple overwrite. + */ + if (F_ISSET(dbp, DB_RE_FIXEDLEN) && + F_ISSET(data, DB_DBT_PARTIAL) && data->dlen != data->size) + return (EINVAL); + + /* + * Figure out how much space the data will take, including if it's a + * partial record. + * + * Fixed-length records: it's an error to specify a record that's + * longer than the fixed-length, and we never require less than + * the fixed-length record size. + */ + data_size = F_ISSET(data, DB_DBT_PARTIAL) ? + CDB___bam_partsize(op, data, h, indx) : data->size; + padrec = 0; + if (F_ISSET(dbp, DB_RE_FIXEDLEN)) { + if (data_size > t->re_len) + return (EINVAL); + if (data_size < t->re_len) { + padrec = 1; + data_size = t->re_len; + } + } + + /* + * Handle partial puts or short fixed-length records: build the + * real record. + * + * XXX + * I'd much rather wait until after we figure out if we need to do + * a split or not, but there are currently too many places that need + * the real record before we get there. Revisit this decision after + * we move off-page duplicates into their own Btree. + */ + if (padrec || F_ISSET(data, DB_DBT_PARTIAL)) { + tdbt = *data; + if ((ret = + CDB___bam_build(dbc, op, &tdbt, h, indx, data_size)) != 0) + return (ret); + data = &tdbt; + } + + /* + * If the user has specified a duplicate comparison function, return + * an error if DB_CURRENT was specified and the replacement data + * doesn't compare equal to the current data. This stops apps from + * screwing up the duplicate sort order. We have to do this after + * we build the real record so that we're comparing the real items. + */ + if (op == DB_CURRENT && dbp->dup_compare != NULL && + CDB___bam_cmp(dbp, data, h, + indx + (TYPE(h) == P_LBTREE ? O_INDX : 0), dbp->dup_compare) != 0) + return (EINVAL); + + /* + * If it's a page of duplicates, call the common code to do the work. + * + * !!! + * Here's where hp and indxp are important. The duplicate code may + * decide to rework/rearrange the pages and indices we're using, so + * the caller must understand that the page stack may change. + */ + if (TYPE(h) == P_DUPLICATE) { + /* If appending a new entry adjust the index for the item. */ + if (op == DB_AFTER || op == DB_CURRENT) + ++*indxp; + + /* + * Put the new/replacement item onto the page. + * + * !!! + * *hp and *indxp may be changed after the return. + */ + if ((ret = CDB___db_dput(dbc, data, hp, indxp)) != 0) + return (ret); + + /* + * XXX + * If this is CURRENT, we do an append followed by a delete, + * because the underlying duplicate code doesn't support the + * replace operation. The tricky part is to make sure we + * delete the proper row. The append may have caused the row + * to move, in which case, the cursor will be updated to point + * at it. This code ASSUMES that the cursor passed in is + * pointing at the current record. + */ + cp = dbc->internal; + if (op == DB_CURRENT) { + /* + * The append may have allocated a new page, in which + * case it discarded the page we held -- re-acquire + * that page. + */ + if (PGNO(*hp) != cp->dpgno) { + if ((ret = CDB_memp_fget( + dbp->mpf, &cp->dpgno, 0, &h)) != 0) + return (ret); + } else + h = *hp; + + /* Delete the original item. */ + if ((ret = CDB___db_drem(dbc, &h, cp->dindx)) != 0) + return (ret); + + /* + * Clear the deleted flag on any cursors referencing + * the item. + */ + (void)CDB___bam_ca_delete(dbp, cp->dpgno, cp->dindx, 0); + + /* + * If the insert and delete are on different pages, we + * have to adjust cursors on both pages. + */ + if (PGNO(*hp) != cp->dpgno) { + indx = cp->dindx; + pgno = cp->dpgno; + CDB___bam_ca_di(dbp, PGNO(*hp), *indxp, 1); + CDB___bam_ca_repl(dbp, + pgno, indx, PGNO(*hp), *indxp); + CDB___bam_ca_di(dbp, pgno, indx + 1, -1); + + if ((ret = CDB_memp_fput( + dbp->mpf, h, DB_MPOOL_DIRTY)) != 0) + return (ret); + } + } else { + h = *hp; + indx = *indxp; + CDB___bam_ca_di(dbp, PGNO(h), indx, 1); + cp->dindx = indx; + cp->dpgno = PGNO(h); + } + goto done; + } + + /* + * If the key or data item won't fit on a page, we'll have to store + * them on overflow pages. + */ + needed = 0; + bigdata = data_size > t->bt_ovflsize; + switch (op) { + case DB_KEYFIRST: + /* We're adding a new key and data pair. */ + bigkey = key->size > t->bt_ovflsize; + if (bigkey) + needed += BOVERFLOW_PSIZE; + else + needed += BKEYDATA_PSIZE(key->size); + if (bigdata) + needed += BOVERFLOW_PSIZE; + else + needed += BKEYDATA_PSIZE(data_size); + break; + case DB_AFTER: + case DB_BEFORE: + case DB_CURRENT: + /* + * We're either overwriting the data item of a key/data pair + * or we're adding the data item only, i.e. a new duplicate. + */ + bigkey = 0; + if (op == DB_CURRENT) { + bk = GET_BKEYDATA(h, + indx + (TYPE(h) == P_LBTREE ? O_INDX : 0)); + if (B_TYPE(bk->type) == B_KEYDATA) + have_bytes = BKEYDATA_PSIZE(bk->len); + else + have_bytes = BOVERFLOW_PSIZE; + need_bytes = 0; + } else { + have_bytes = 0; + need_bytes = sizeof(db_indx_t); + } + if (bigdata) + need_bytes += BOVERFLOW_PSIZE; + else + need_bytes += BKEYDATA_PSIZE(data_size); + + if (have_bytes < need_bytes) + needed += need_bytes - have_bytes; + break; + default: + return (EINVAL); + } + + /* + * If there's not enough room, or the user has put a ceiling on the + * number of keys permitted in the page, split the page. + * + * XXX + * The t->bt_maxkey test here may be insufficient -- do we have to + * check in the btree split code, so we don't undo it there!?!? + */ + if (P_FREESPACE(h) < needed || + (t->bt_maxkey != 0 && NUM_ENT(h) > t->bt_maxkey)) + return (DB_NEEDSPLIT); + + /* + * The code breaks it up into five cases: + * + * 1. Insert a new key/data pair. + * 2. Append a new data item (a new duplicate). + * 3. Insert a new data item (a new duplicate). + * 4. Delete and re-add the data item (overflow item). + * 5. Overwrite the data item. + */ + switch (op) { + case DB_KEYFIRST: /* 1. Insert a new key/data pair. */ + if (bigkey) { + if ((ret = CDB___bam_ovput(dbc, h, indx, key)) != 0) + return (ret); + } else + if ((ret = CDB___db_pitem(dbc, h, indx, + BKEYDATA_SIZE(key->size), NULL, key)) != 0) + return (ret); + + CDB___bam_ca_di(dbp, PGNO(h), indx, 1); + ++indx; + break; + case DB_AFTER: /* 2. Append a new data item. */ + if (TYPE(h) == P_LBTREE) { + /* + * Adjust the cursor and copy in the key for the + * duplicate. + */ + if ((ret = + CDB___bam_adjindx(dbc, h, indx + P_INDX, indx, 1)) != 0) + return (ret); + + indx += 3; + dupadjust = 1; + + *indxp += 2; + } else { + ++indx; + CDB___bam_ca_di(dbp, PGNO(h), indx, 1); + + *indxp += 1; + } + break; + case DB_BEFORE: /* 3. Insert a new data item. */ + if (TYPE(h) == P_LBTREE) { + /* + * Adjust the cursor and copy in the key for the + * duplicate. + */ + if ((ret = CDB___bam_adjindx(dbc, h, indx, indx, 1)) != 0) + return (ret); + + ++indx; + dupadjust = 1; + } else + CDB___bam_ca_di(dbp, PGNO(h), indx, 1); + break; + case DB_CURRENT: + if (TYPE(h) == P_LBTREE) { + ++indx; + dupadjust = 1; + + /* + * In a Btree deleted records aren't counted (deleted + * records are counted in a Recno because all accesses + * are based on record number). If it's a Btree and + * it's a DB_CURRENT operation overwriting a previously + * deleted record, increment the record count. + */ + was_deleted = B_DISSET(bk->type); + } + + /* + * 4. Delete and re-add the data item. + * + * If we're dealing with offpage items, we have to delete and + * then re-add the item. + */ + if (bigdata || B_TYPE(bk->type) != B_KEYDATA) { + if ((ret = CDB___bam_ditem(dbc, h, indx)) != 0) + return (ret); + break; + } + + /* 5. Overwrite the data item. */ + replace = 1; + break; + default: + return (EINVAL); + } + + /* Add the data. */ + if (bigdata) { + if ((ret = CDB___bam_ovput(dbc, h, indx, data)) != 0) + return (ret); + } else { + BKEYDATA __bk; + DBT __hdr; + + if (LF_ISSET(BI_DELETED)) { + B_TSET(__bk.type, B_KEYDATA, 1); + __bk.len = data->size; + __hdr.data = &__bk; + __hdr.size = SSZA(BKEYDATA, data); + ret = CDB___db_pitem(dbc, h, indx, + BKEYDATA_SIZE(data->size), &__hdr, data); + } else if (replace) + ret = CDB___bam_ritem(dbc, h, indx, data); + else + ret = CDB___db_pitem(dbc, h, indx, + BKEYDATA_SIZE(data->size), NULL, data); + if (ret != 0) + return (ret); + } + if ((ret = CDB_memp_fset(dbp->mpf, h, DB_MPOOL_DIRTY)) != 0) + return (ret); + + /* + * Adjust the cursors in general. After that's done, reset the current + * cursor to point to the new item. + */ + if (op == DB_CURRENT) + (void)CDB___bam_ca_delete(dbp, PGNO(h), + TYPE(h) == P_LBTREE ? indx - O_INDX : indx, 0); + else { + CDB___bam_ca_di(dbp, PGNO(h), indx, 1); + ((BTREE_CURSOR *)dbc->internal)->indx = + TYPE(h) == P_LBTREE ? indx - O_INDX : indx; + } + + /* + * If we've changed the record count, update the tree. Record counts + * need to be updated in Recno databases and in Btree databases where + * we are supporting records. In both cases, adjust the count if the + * operation wasn't performed on the current record or when the record + * was previously deleted. + */ + if ((op != DB_CURRENT || was_deleted) && + (F_ISSET(dbp, DB_BT_RECNUM) || dbp->type == DB_RECNO)) + if ((ret = CDB___bam_adjust(dbc, 1)) != 0) + return (ret); + + /* + * If a Btree leaf page is at least 50% full and we may have added or + * modified a duplicate data item, see if the set of duplicates takes + * up at least 25% of the space on the page. If it does, move it off + * int its own page. + */ + if (dupadjust && P_FREESPACE(h) <= dbp->pgsize / 2) { + --indx; + if ((ret = CDB___bam_ndup(dbc, h, indx)) != 0) + return (ret); + } + + /* If we've modified a recno file, set the flag. */ +done: if (dbp->type == DB_RECNO) + F_SET(t, RECNO_MODIFIED); + + return (ret); +} + +/* + * CDB___bam_partsize -- + * Figure out how much space a partial data item is in total. + * + * PUBLIC: u_int32_t CDB___bam_partsize __P((u_int32_t, DBT *, PAGE *, u_int32_t)); + */ +u_int32_t +CDB___bam_partsize(op, data, h, indx) + u_int32_t op, indx; + DBT *data; + PAGE *h; +{ + BKEYDATA *bk; + u_int32_t nbytes; + + /* + * If the record doesn't already exist, it's simply the data we're + * provided. + */ + if (op != DB_CURRENT) + return (data->doff + data->size); + + /* + * Otherwise, it's the data provided plus any already existing data + * that we're not replacing. + */ + bk = GET_BKEYDATA(h, indx + (TYPE(h) == P_LBTREE ? O_INDX : 0)); + nbytes = + B_TYPE(bk->type) == B_OVERFLOW ? ((BOVERFLOW *)bk)->tlen : bk->len; + + /* + * There are really two cases here: + * + * Case 1: We are replacing some bytes that do not exist (i.e., they + * are past the end of the record). In this case the number of bytes + * we are replacing is irrelevant and all we care about is how many + * bytes we are going to add from offset. So, the new record length + * is going to be the size of the new bytes (size) plus wherever those + * new bytes begin (doff). + * + * Case 2: All the bytes we are replacing exist. Therefore, the new + * size is the oldsize (nbytes) minus the bytes we are replacing (dlen) + * plus the bytes we are adding (size). + */ + if (nbytes < data->doff + data->dlen) /* Case 1 */ + return (data->doff + data->size); + + return (nbytes + data->size - data->dlen); /* Case 2 */ +} + +/* + * CDB___bam_build -- + * Build the real record for a partial put, or short fixed-length record. + * + * PUBLIC: int CDB___bam_build __P((DBC *, u_int32_t, + * PUBLIC: DBT *, PAGE *, u_int32_t, u_int32_t)); + */ +int +CDB___bam_build(dbc, op, dbt, h, indx, nbytes) + DBC *dbc; + u_int32_t op, indx, nbytes; + DBT *dbt; + PAGE *h; +{ + BKEYDATA *bk, tbk; + BOVERFLOW *bo; + BTREE *t; + DB *dbp; + DBT copy; + u_int32_t len, tlen; + u_int8_t *p; + int ret; + + COMPQUIET(bo, NULL); + + dbp = dbc->dbp; + t = dbp->bt_internal; + + /* We use the record data return memory, it's only a short-term use. */ + if (dbc->rdata.ulen < nbytes) { + if ((ret = + CDB___os_realloc(nbytes, NULL, &dbc->rdata.data)) != 0) { + dbc->rdata.ulen = 0; + dbc->rdata.data = NULL; + return (ret); + } + dbc->rdata.ulen = nbytes; + } + + /* + * We use nul or pad bytes for any part of the record that isn't + * specified; get it over with. + */ + memset(dbc->rdata.data, + F_ISSET(dbp, DB_RE_FIXEDLEN) ? t->re_pad : 0, nbytes); + + /* + * In the next clauses, we need to do three things: a) set p to point + * to the place at which to copy the user's data, b) set tlen to the + * total length of the record, not including the bytes contributed by + * the user, and c) copy any valid data from an existing record. If + * it's not a partial put (this code is called for both partial puts + * and fixed-length record padding) or it's a new key, we can cut to + * the chase. + */ + if (!F_ISSET(dbt, DB_DBT_PARTIAL) || op != DB_CURRENT) { + p = (u_int8_t *)dbc->rdata.data + dbt->doff; + tlen = dbt->doff; + goto user_copy; + } + + /* Find the current record. */ + if (indx < NUM_ENT(h)) { + bk = GET_BKEYDATA(h, indx + (TYPE(h) == P_LBTREE ? O_INDX : 0)); + bo = (BOVERFLOW *)bk; + } else { + bk = &tbk; + B_TSET(bk->type, B_KEYDATA, 0); + bk->len = 0; + } + if (B_TYPE(bk->type) == B_OVERFLOW) { + /* + * In the case of an overflow record, we shift things around + * in the current record rather than allocate a separate copy. + */ + memset(©, 0, sizeof(copy)); + if ((ret = CDB___db_goff(dbp, ©, bo->tlen, + bo->pgno, &dbc->rdata.data, &dbc->rdata.ulen)) != 0) + return (ret); + + /* Skip any leading data from the original record. */ + tlen = dbt->doff; + p = (u_int8_t *)dbc->rdata.data + dbt->doff; + + /* + * Copy in any trailing data from the original record. + * + * If the original record was larger than the original offset + * plus the bytes being deleted, there is trailing data in the + * original record we need to preserve. If we aren't deleting + * the same number of bytes as we're inserting, copy it up or + * down, into place. + * + * Use memmove(), the regions may overlap. + */ + if (bo->tlen > dbt->doff + dbt->dlen) { + len = bo->tlen - (dbt->doff + dbt->dlen); + if (dbt->dlen != dbt->size) + memmove(p + dbt->size, p + dbt->dlen, len); + tlen += len; + } + } else { + /* Copy in any leading data from the original record. */ + memcpy(dbc->rdata.data, + bk->data, dbt->doff > bk->len ? bk->len : dbt->doff); + tlen = dbt->doff; + p = (u_int8_t *)dbc->rdata.data + dbt->doff; + + /* Copy in any trailing data from the original record. */ + len = dbt->doff + dbt->dlen; + if (bk->len > len) { + memcpy(p + dbt->size, bk->data + len, bk->len - len); + tlen += bk->len - len; + } + } + +user_copy: + /* + * Copy in the application provided data -- p and tlen must have been + * initialized above. + */ + memcpy(p, dbt->data, dbt->size); + tlen += dbt->size; + + /* Set the DBT to reference our new record. */ + dbc->rdata.size = F_ISSET(dbp, DB_RE_FIXEDLEN) ? t->re_len : tlen; + dbc->rdata.dlen = 0; + dbc->rdata.doff = 0; + dbc->rdata.flags = 0; + *dbt = dbc->rdata; + return (0); +} + +/* + * OVPUT -- + * Copy an overflow item onto a page. + */ +#undef OVPUT +#define OVPUT(h, indx, bo) do { \ + DBT __hdr; \ + memset(&__hdr, 0, sizeof(__hdr)); \ + __hdr.data = &bo; \ + __hdr.size = BOVERFLOW_SIZE; \ + if ((ret = CDB___db_pitem(dbc, \ + h, indx, BOVERFLOW_SIZE, &__hdr, NULL)) != 0) \ + return (ret); \ +} while (0) + +/* + * CDB___bam_ovput -- + * Build an overflow item and put it on the page. + */ +static int +CDB___bam_ovput(dbc, h, indx, item) + DBC *dbc; + PAGE *h; + u_int32_t indx; + DBT *item; +{ + BOVERFLOW bo; + int ret; + + UMRW(bo.unused1); + B_TSET(bo.type, B_OVERFLOW, 0); + UMRW(bo.unused2); + if ((ret = CDB___db_poff(dbc, item, &bo.pgno)) != 0) + return (ret); + bo.tlen = item->size; + + OVPUT(h, indx, bo); + + return (0); +} + +/* + * CDB___bam_ritem -- + * Replace an item on a page. + * + * PUBLIC: int CDB___bam_ritem __P((DBC *, PAGE *, u_int32_t, DBT *)); + */ +int +CDB___bam_ritem(dbc, h, indx, data) + DBC *dbc; + PAGE *h; + u_int32_t indx; + DBT *data; +{ + BKEYDATA *bk; + DB *dbp; + DBT orig, repl; + db_indx_t cnt, lo, ln, min, off, prefix, suffix; + int32_t nbytes; + int ret; + u_int8_t *p, *t; + + dbp = dbc->dbp; + + /* + * Replace a single item onto a page. The logic figuring out where + * to insert and whether it fits is handled in the caller. All we do + * here is manage the page shuffling. + */ + bk = GET_BKEYDATA(h, indx); + + /* Log the change. */ + if (DB_LOGGING(dbc)) { + /* + * We might as well check to see if the two data items share + * a common prefix and suffix -- it can save us a lot of log + * message if they're large. + */ + min = data->size < bk->len ? data->size : bk->len; + for (prefix = 0, + p = bk->data, t = data->data; + prefix < min && *p == *t; ++prefix, ++p, ++t) + ; + + min -= prefix; + for (suffix = 0, + p = (u_int8_t *)bk->data + bk->len - 1, + t = (u_int8_t *)data->data + data->size - 1; + suffix < min && *p == *t; ++suffix, --p, --t) + ; + + /* We only log the parts of the keys that have changed. */ + orig.data = (u_int8_t *)bk->data + prefix; + orig.size = bk->len - (prefix + suffix); + repl.data = (u_int8_t *)data->data + prefix; + repl.size = data->size - (prefix + suffix); + if ((ret = CDB___bam_repl_log(dbp->dbenv, dbc->txn, + &LSN(h), 0, dbp->log_fileid, PGNO(h), &LSN(h), + (u_int32_t)indx, (u_int32_t)B_DISSET(bk->type), + &orig, &repl, (u_int32_t)prefix, (u_int32_t)suffix)) != 0) + return (ret); + } + + /* + * Set references to the first in-use byte on the page and the + * first byte of the item being replaced. + */ + p = (u_int8_t *)h + HOFFSET(h); + t = (u_int8_t *)bk; + + /* + * If the entry is growing in size, shift the beginning of the data + * part of the page down. If the entry is shrinking in size, shift + * the beginning of the data part of the page up. Use memmove(3), + * the regions overlap. + */ + lo = BKEYDATA_SIZE(bk->len); + ln = BKEYDATA_SIZE(data->size); + if (lo != ln) { + nbytes = lo - ln; /* Signed difference. */ + if (p == t) /* First index is fast. */ + h->inp[indx] += nbytes; + else { /* Else, shift the page. */ + memmove(p + nbytes, p, t - p); + + /* Adjust the indices' offsets. */ + off = h->inp[indx]; + for (cnt = 0; cnt < NUM_ENT(h); ++cnt) + if (h->inp[cnt] <= off) + h->inp[cnt] += nbytes; + } + + /* Clean up the page and adjust the item's reference. */ + HOFFSET(h) += nbytes; + t += nbytes; + } + + /* Copy the new item onto the page. */ + bk = (BKEYDATA *)t; + B_TSET(bk->type, B_KEYDATA, 0); + bk->len = data->size; + memcpy(bk->data, data->data, data->size); + + return (0); +} + +/* + * CDB___bam_ndup -- + * Check to see if the duplicate set at indx should have its own page. + * If it should, create it. + */ +static int +CDB___bam_ndup(dbc, h, indx) + DBC *dbc; + PAGE *h; + u_int32_t indx; +{ + BKEYDATA *bk; + BOVERFLOW bo; + DB *dbp; + DBT hdr; + PAGE *cp; + db_indx_t cnt, cpindx, first, sz; + int ret; + + dbp = dbc->dbp; + + /* + * Count the duplicate records and calculate how much room they're + * using on the page. + */ + while (indx > 0 && h->inp[indx] == h->inp[indx - P_INDX]) + indx -= P_INDX; + for (cnt = 0, sz = 0, first = indx;; ++cnt, indx += P_INDX) { + if (indx >= NUM_ENT(h) || h->inp[first] != h->inp[indx]) + break; + bk = GET_BKEYDATA(h, indx); + sz += B_TYPE(bk->type) == B_KEYDATA ? + BKEYDATA_PSIZE(bk->len) : BOVERFLOW_PSIZE; + bk = GET_BKEYDATA(h, indx + O_INDX); + sz += B_TYPE(bk->type) == B_KEYDATA ? + BKEYDATA_PSIZE(bk->len) : BOVERFLOW_PSIZE; + } + + /* + * We have to do these checks when the user is replacing the cursor's + * data item -- if the application replaces a duplicate item with a + * larger data item, it can increase the amount of space used by the + * duplicates, requiring this check. But that means it may not be a + * duplicate after all. + */ + if (cnt == 1) + return (0); + + /* + * If this set of duplicates is using more than 25% of the page, move + * them off. The choice of 25% is a WAG, but it has to be small enough + * that we can always split regardless of the presence of duplicates. + */ + if (sz < dbp->pgsize / 4) + return (0); + + /* Get a new page. */ + if ((ret = CDB___db_new(dbc, P_DUPLICATE, &cp)) != 0) + return (ret); + + /* + * Move this set of duplicates off the page. First points to the first + * key of the first duplicate key/data pair, cnt is the number of pairs + * we're dealing with. + */ + memset(&hdr, 0, sizeof(hdr)); + for (indx = first + O_INDX, cpindx = 0;; ++cpindx) { + /* Copy the entry to the new page. */ + bk = GET_BKEYDATA(h, indx); + hdr.data = bk; + hdr.size = B_TYPE(bk->type) == B_KEYDATA ? + BKEYDATA_SIZE(bk->len) : BOVERFLOW_SIZE; + if ((ret = + CDB___db_pitem(dbc, cp, cpindx, hdr.size, &hdr, NULL)) != 0) + goto err; + + /* Move cursors referencing the old entry to the new entry. */ + CDB___bam_ca_dup(dbp, + PGNO(h), first, indx - O_INDX, PGNO(cp), cpindx); + + /* Delete the data item. */ + if ((ret = CDB___db_ditem(dbc, h, indx, hdr.size)) != 0) + goto err; + + CDB___bam_ca_di(dbp, PGNO(h), indx, -1); + + /* Delete all but the first reference to the key. */ + if (--cnt == 0) + break; + if ((ret = CDB___bam_adjindx(dbc, h, indx, first, 0)) != 0) + goto err; + } + + /* Put in a new data item that points to the duplicates page. */ + UMRW(bo.unused1); + B_TSET(bo.type, B_DUPLICATE, 0); + UMRW(bo.unused2); + bo.pgno = cp->pgno; + bo.tlen = 0; + + OVPUT(h, indx, bo); + + return (CDB_memp_fput(dbp->mpf, cp, DB_MPOOL_DIRTY)); + +err: (void)CDB___db_free(dbc, cp); + return (ret); +} |