db

hash_dup.c

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00001 /*-
00002  * See the file LICENSE for redistribution information.
00003  *
00004  * Copyright (c) 1996, 1997, 1998, 1999, 2000
00005  * Sleepycat Software. All rights reserved.
00006  */
00007 /*
00008  * Copyright (c) 1990, 1993, 1994
00009  * The Regents of the University of California. All rights reserved.
00010  *
00011  * This code is derived from software contributed to Berkeley by
00012  * Margo Seltzer.
00013  *
00014  * Redistribution and use in source and binary forms, with or without
00015  * modification, are permitted provided that the following conditions
00016  * are met:
00017  * 1. Redistributions of source code must retain the above copyright
00018  * notice, this list of conditions and the following disclaimer.
00019  * 2. Redistributions in binary form must reproduce the above copyright
00020  * notice, this list of conditions and the following disclaimer in the
00021  * documentation and/or other materials provided with the distribution.
00022  * 3. Neither the name of the University nor the names of its contributors
00023  * may be used to endorse or promote products derived from this software
00024  * without specific prior written permission.
00025  *
00026  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
00027  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00028  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00029  * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
00030  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
00031  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
00032  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
00033  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00034  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
00035  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
00036  * SUCH DAMAGE.
00037  */
00038 #include "config.h"
00039 
00040 #ifndef lint
00041 static const char revid[] = "$Id: hash__dup_8c-source.html,v 1.1 2008年06月08日 10:19:25 sebdiaz Exp $";
00042 #endif /* not lint */
00043 
00044 /*
00045  * PACKAGE: hashing
00046  *
00047  * DESCRIPTION:
00048  * Manipulation of duplicates for the hash package.
00049  *
00050  * ROUTINES:
00051  *
00052  * External
00053  * __add_dup
00054  * Internal
00055  */
00056 
00057 #ifndef NO_SYSTEM_INCLUDES
00058 #include <sys/types.h>
00059 
00060 #include <errno.h>
00061 #include <string.h>
00062 #endif
00063 
00064 #include "db_int.h"
00065 #include "db_page.h"
00066 #include "hash.h"
00067 #include "btree.h"
00068 
00069 static int __ham_check_move __P((DBC *, u_int32_t));
00070 static int __ham_dcursor __P((DBC *, db_pgno_t, u_int32_t));
00071 
00072 /*
00073  * Called from hash_access to add a duplicate key. nval is the new
00074  * value that we want to add. The flags correspond to the flag values
00075  * to cursor_put indicating where to add the new element.
00076  * There are 4 cases.
00077  * Case 1: The existing duplicate set already resides on a separate page.
00078  * We return and let the common code handle this.
00079  * Case 2: The element is small enough to just be added to the existing set.
00080  * Case 3: The element is large enough to be a big item, so we're going to
00081  * have to push the set onto a new page.
00082  * Case 4: The element is large enough to push the duplicate set onto a
00083  * separate page.
00084  *
00085  * PUBLIC: int CDB___ham_add_dup __P((DBC *, DBT *, u_int32_t, db_pgno_t *));
00086  */
00087 int
00088 CDB___ham_add_dup(dbc, nval, flags, pgnop)
00089 DBC *dbc;
00090 DBT *nval;
00091 u_int32_t flags;
00092 db_pgno_t *pgnop;
00093 {
00094 DB *dbp;
00095 HASH_CURSOR *hcp;
00096 DBT pval, tmp_val;
00097 u_int32_t add_bytes, new_size;
00098 int cmp, ret;
00099 u_int8_t *hk;
00100 
00101 dbp = dbc->dbp;
00102 hcp = (HASH_CURSOR *)dbc->internal;
00103 
00104 DB_ASSERT(flags != DB_CURRENT);
00105 
00106 add_bytes = nval->size +
00107 (F_ISSET(nval, DB_DBT_PARTIAL) ? nval->doff : 0);
00108 add_bytes = DUP_SIZE(add_bytes);
00109 
00110 if ((ret = __ham_check_move(dbc, add_bytes)) != 0)
00111 return (ret);
00112 
00113 /*
00114  * Check if resulting duplicate set is going to need to go
00115  * onto a separate duplicate page. If so, convert the
00116  * duplicate set and add the new one. After conversion,
00117  * hcp->dndx is the first free ndx or the index of the
00118  * current pointer into the duplicate set.
00119  */
00120 hk = H_PAIRDATA(hcp->page, hcp->indx);
00121 new_size =
00122 LEN_HKEYDATA(hcp->page, dbp->pgsize, H_DATAINDEX(hcp->indx)) +
00123 add_bytes;
00124 
00125 /*
00126  * We convert to off-page duplicates if the item is a big item,
00127  * the addition of the new item will make the set large, or
00128  * if there isn't enough room on this page to add the next item.
00129  */
00130 if (HPAGE_PTYPE(hk) != H_OFFDUP &&
00131 (HPAGE_PTYPE(hk) == H_OFFPAGE || ISBIG(hcp, new_size) ||
00132 add_bytes > P_FREESPACE(hcp->page))) {
00133 
00134 if ((ret = CDB___ham_dup_convert(dbc)) != 0)
00135 return (ret);
00136 return(hcp->opd->c_am_put(hcp->opd,
00137 NULL, nval, flags, NULL));
00138 }
00139 
00140 /* There are two separate cases here: on page and off page. */
00141 if (HPAGE_PTYPE(hk) != H_OFFDUP) {
00142 if (HPAGE_PTYPE(hk) != H_DUPLICATE) {
00143 pval.flags = 0;
00144 pval.data = HKEYDATA_DATA(hk);
00145 pval.size = LEN_HDATA(hcp->page, dbp->pgsize,
00146 hcp->indx);
00147 if ((ret = CDB___ham_make_dup(dbp->dbenv,
00148 &pval, &tmp_val, &dbc->rdata.data,
00149 &dbc->rdata.ulen)) != 0 || (ret =
00150 CDB___ham_replpair(dbc, &tmp_val, 1)) != 0)
00151 return (ret);
00152 hk = H_PAIRDATA(hcp->page, hcp->indx);
00153 HPAGE_PTYPE(hk) = H_DUPLICATE;
00154 
00155 /*
00156  * Update the cursor position since we now are in
00157  * duplicates.
00158  */
00159 F_SET(hcp, H_ISDUP);
00160 hcp->dup_off = 0;
00161 hcp->dup_len = pval.size;
00162 hcp->dup_tlen = DUP_SIZE(hcp->dup_len);
00163 }
00164 
00165 /* Now make the new entry a duplicate. */
00166 if ((ret = CDB___ham_make_dup(dbp->dbenv, nval,
00167 &tmp_val, &dbc->rdata.data, &dbc->rdata.ulen)) != 0)
00168 return (ret);
00169 
00170 tmp_val.dlen = 0;
00171 switch (flags) { /* On page. */
00172 case DB_KEYFIRST:
00173 case DB_KEYLAST:
00174 case DB_NODUPDATA:
00175 if (dbp->dup_compare != NULL) {
00176 CDB___ham_dsearch(dbc, nval, &tmp_val.doff, &cmp);
00177 
00178 /* dup dups are not supported w/ sorted dups */
00179 if (cmp == 0)
00180 return (CDB___db_duperr(dbp, flags));
00181 } else {
00182 hcp->dup_tlen = LEN_HDATA(hcp->page,
00183 dbp->pgsize, hcp->indx);
00184 hcp->dup_len = nval->size;
00185 F_SET(hcp, H_ISDUP);
00186 if (flags == DB_KEYFIRST)
00187 hcp->dup_off = tmp_val.doff = 0;
00188 else
00189 hcp->dup_off =
00190 tmp_val.doff = hcp->dup_tlen;
00191 }
00192 break;
00193 case DB_BEFORE:
00194 tmp_val.doff = hcp->dup_off;
00195 break;
00196 case DB_AFTER:
00197 tmp_val.doff = hcp->dup_off + DUP_SIZE(hcp->dup_len);
00198 break;
00199 }
00200 /* Add the duplicate. */
00201 ret = CDB___ham_replpair(dbc, &tmp_val, 0);
00202 if (ret == 0)
00203 ret = CDB___ham_dirty_page(dbp, hcp->page);
00204 
00205 /* Now, update the cursor if necessary. */
00206 switch (flags) {
00207 case DB_AFTER:
00208 hcp->dup_off += DUP_SIZE(hcp->dup_len);
00209 hcp->dup_len = nval->size;
00210 hcp->dup_tlen += DUP_SIZE(nval->size);
00211 break;
00212 case DB_KEYFIRST:
00213 case DB_KEYLAST:
00214 case DB_BEFORE:
00215 hcp->dup_tlen += DUP_SIZE(nval->size);
00216 hcp->dup_len = nval->size;
00217 break;
00218 }
00219 CDB___ham_c_update(dbc, hcp->pgno, tmp_val.size, 1, 1);
00220 return (ret);
00221 }
00222 
00223 /*
00224  * If we get here, then we're on duplicate pages; set pgnop and
00225  * return so the common code can handle it.
00226  */
00227 memcpy(pgnop,
00228 HOFFDUP_PGNO(H_PAIRDATA(hcp->page, hcp->indx)), sizeof(db_pgno_t));
00229 
00230 return (ret);
00231 }
00232 
00233 /*
00234  * Convert an on-page set of duplicates to an offpage set of duplicates.
00235  *
00236  * PUBLIC: int CDB___ham_dup_convert __P((DBC *));
00237  */
00238 int
00239 CDB___ham_dup_convert(dbc)
00240 DBC *dbc;
00241 {
00242 DB *dbp;
00243 DBC **hcs;
00244 PAGE *dp;
00245 HASH_CURSOR *hcp;
00246 BOVERFLOW bo;
00247 DBT dbt;
00248 HOFFPAGE ho;
00249 db_indx_t i, len, off;
00250 int c, ret, t_ret;
00251 u_int8_t *p, *pend;
00252 
00253 dbp = dbc->dbp;
00254 hcp = (HASH_CURSOR *)dbc->internal;
00255 
00256 /*
00257  * Create a new page for the duplicates.
00258  */
00259 if ((ret = CDB___db_new(dbc,
00260 ((dbp->dup_compare == NULL ? P_LRECNO : P_LDUP) | dbp->tags), &dp)) != 0)
00261 return (ret);
00262 P_INIT(dp, dbp->pgsize,
00263 dp->pgno, PGNO_INVALID, PGNO_INVALID, LEAFLEVEL, TYPE(dp), TAGS(dp));
00264 
00265 /*
00266  * Get the list of cursors that may need to be updated.
00267  */
00268 if ((ret = CDB___ham_get_clist(dbp,
00269 PGNO(hcp->page), (u_int32_t)hcp->indx, &hcs)) != 0)
00270 return (ret);
00271 
00272 /*
00273  * Now put the duplicates onto the new page.
00274  */
00275 dbt.flags = 0;
00276 switch (HPAGE_PTYPE(H_PAIRDATA(hcp->page, hcp->indx))) {
00277 case H_KEYDATA:
00278 /* Simple case, one key on page; move it to dup page. */
00279 dbt.size = LEN_HDATA(hcp->page, dbp->pgsize, hcp->indx);
00280 dbt.data = HKEYDATA_DATA(H_PAIRDATA(hcp->page, hcp->indx));
00281 ret = CDB___db_pitem(dbc,
00282 dp, 0, BKEYDATA_SIZE(dbt.size), NULL, &dbt);
00283 goto finish;
00284 case H_OFFPAGE:
00285 /* Simple case, one key on page; move it to dup page. */
00286 memcpy(&ho,
00287 P_ENTRY(hcp->page, H_DATAINDEX(hcp->indx)), HOFFPAGE_SIZE);
00288 UMRW(bo.unused1);
00289 B_TSET(bo.type, ho.type, 0);
00290 UMRW(bo.unused2);
00291 bo.pgno = ho.pgno;
00292 bo.tlen = ho.tlen;
00293 dbt.size = BOVERFLOW_SIZE;
00294 dbt.data = &bo;
00295 
00296 ret = CDB___db_pitem(dbc, dp, 0, dbt.size, &dbt, NULL);
00297 
00298 finish: if (ret == 0) {
00299 CDB___ham_dirty_page(dbp, dp);
00300 /*
00301  * Update any other cursors
00302  */
00303 for (c = 0; hcs != NULL && hcs[c] != NULL; c++)
00304 if ((ret = __ham_dcursor(hcs[c],
00305 PGNO(dp), 0)) != 0)
00306 break;
00307 }
00308 break;
00309 
00310 case H_DUPLICATE:
00311 p = HKEYDATA_DATA(H_PAIRDATA(hcp->page, hcp->indx));
00312 pend = p +
00313 LEN_HDATA(hcp->page, dbp->pgsize, hcp->indx);
00314 
00315 /*
00316  * We need to maintain the duplicate cursor position.
00317  * Keep track of where we are in the duplicate set via
00318  * the offset, and when it matches the one in the cursor,
00319  * set the off-page duplicate cursor index to the current
00320  * index.
00321  */
00322 for (off = 0, i = 0; p < pend; i++) {
00323 memcpy(&len, p, sizeof(db_indx_t));
00324 dbt.size = len;
00325 p += sizeof(db_indx_t);
00326 dbt.data = p;
00327 p += len + sizeof(db_indx_t);
00328 if ((ret = CDB___db_pitem(dbc, dp,
00329 i, BKEYDATA_SIZE(dbt.size), NULL, &dbt)) != 0)
00330 break;
00331 /*
00332  * Update any other cursors
00333  */
00334 for (c = 0; hcs != NULL && hcs[c] != NULL; c++)
00335 if (((HASH_CURSOR *)(hcs[c]->internal))->dup_off
00336 == off && (ret = __ham_dcursor(hcs[c],
00337 PGNO(dp), i)) != 0)
00338 goto out;
00339 off += len + 2 * sizeof(db_indx_t);
00340 }
00341 out: break;
00342 
00343 default:
00344 ret = CDB___db_pgfmt(dbp, (u_long)hcp->pgno);
00345 break;
00346 }
00347 if (ret == 0) {
00348 /*
00349  * Now attach this to the source page in place of
00350  * the old duplicate item.
00351  */
00352 CDB___ham_move_offpage(dbc, hcp->page,
00353 (u_int32_t)H_DATAINDEX(hcp->indx), PGNO(dp));
00354 
00355 ret = CDB___ham_dirty_page(dbp, hcp->page);
00356 if ((t_ret = CDB___ham_put_page(dbp, dp, 1)) != 0)
00357 ret = t_ret;
00358 hcp->dup_tlen = hcp->dup_off = hcp->dup_len = 0;
00359 } else
00360 (void)CDB___db_free(dbc, dp);
00361 
00362 if (hcs != NULL)
00363 CDB___os_free(hcs, 0);
00364 
00365 return (ret);
00366 }
00367 
00368 /*
00369  * CDB___ham_make_dup
00370  *
00371  * Take a regular dbt and make it into a duplicate item with all the partial
00372  * information set appropriately. If the incoming dbt is a partial, assume
00373  * we are creating a new entry and make sure that we do any initial padding.
00374  *
00375  * PUBLIC: int CDB___ham_make_dup __P((DB_ENV *,
00376  * PUBLIC: const DBT *, DBT *d, void **, u_int32_t *));
00377  */
00378 int
00379 CDB___ham_make_dup(dbenv, notdup, duplicate, bufp, sizep)
00380 DB_ENV *dbenv;
00381 const DBT *notdup;
00382 DBT *duplicate;
00383 void **bufp;
00384 u_int32_t *sizep;
00385 {
00386 db_indx_t tsize, item_size;
00387 int ret;
00388 u_int8_t *p;
00389 
00390 item_size = (db_indx_t)notdup->size;
00391 if (F_ISSET(notdup, DB_DBT_PARTIAL))
00392 item_size += notdup->doff;
00393 
00394 tsize = DUP_SIZE(item_size);
00395 if ((ret = CDB___ham_init_dbt(dbenv, duplicate, tsize, bufp, sizep)) != 0)
00396 return (ret);
00397 
00398 duplicate->dlen = 0;
00399 duplicate->flags = notdup->flags;
00400 F_SET(duplicate, DB_DBT_PARTIAL);
00401 
00402 p = duplicate->data;
00403 memcpy(p, &item_size, sizeof(db_indx_t));
00404 p += sizeof(db_indx_t);
00405 if (F_ISSET(notdup, DB_DBT_PARTIAL)) {
00406 memset(p, 0, notdup->doff);
00407 p += notdup->doff;
00408 }
00409 memcpy(p, notdup->data, notdup->size);
00410 p += notdup->size;
00411 memcpy(p, &item_size, sizeof(db_indx_t));
00412 
00413 duplicate->doff = 0;
00414 duplicate->dlen = notdup->size;
00415 
00416 return (0);
00417 }
00418 
00419 /*
00420  * __ham_check_move --
00421  *
00422  * Check if we can do whatever we need to on this page. If not,
00423  * then we'll have to move the current element to a new page.
00424  */
00425 static int
00426 __ham_check_move(dbc, add_len)
00427 DBC *dbc;
00428 u_int32_t add_len;
00429 {
00430 DB *dbp;
00431 HASH_CURSOR *hcp;
00432 DBT k, d;
00433 DB_LSN new_lsn;
00434 PAGE *next_pagep;
00435 db_pgno_t next_pgno;
00436 u_int32_t new_datalen, old_len, rectype;
00437 u_int8_t *hk;
00438 int ret;
00439 
00440 dbp = dbc->dbp;
00441 hcp = (HASH_CURSOR *)dbc->internal;
00442 
00443 hk = H_PAIRDATA(hcp->page, hcp->indx);
00444 
00445 /*
00446  * If the item is already off page duplicates or an offpage item,
00447  * then we know we can do whatever we need to do in-place
00448  */
00449 if (HPAGE_PTYPE(hk) == H_OFFDUP || HPAGE_PTYPE(hk) == H_OFFPAGE)
00450 return (0);
00451 
00452 old_len = LEN_HITEM(hcp->page, dbp->pgsize, H_DATAINDEX(hcp->indx));
00453 new_datalen = old_len - HKEYDATA_SIZE(0) + add_len;
00454 if (HPAGE_PTYPE(hk) != H_DUPLICATE)
00455 new_datalen += DUP_SIZE(0);
00456 
00457 /*
00458  * We need to add a new page under two conditions:
00459  * 1. The addition makes the total data length cross the BIG
00460  * threshold and the OFFDUP structure won't fit on this page.
00461  * 2. The addition does not make the total data cross the
00462  * threshold, but the new data won't fit on the page.
00463  * If neither of these is true, then we can return.
00464  */
00465 if (ISBIG(hcp, new_datalen) && (old_len > HOFFDUP_SIZE ||
00466 HOFFDUP_SIZE - old_len <= P_FREESPACE(hcp->page)))
00467 return (0);
00468 
00469 if (!ISBIG(hcp, new_datalen) && add_len <= P_FREESPACE(hcp->page))
00470 return (0);
00471 
00472 /*
00473  * If we get here, then we need to move the item to a new page.
00474  * Check if there are more pages in the chain.
00475  */
00476 
00477 new_datalen = ISBIG(hcp, new_datalen) ?
00478 HOFFDUP_SIZE : HKEYDATA_SIZE(new_datalen);
00479 
00480 next_pagep = NULL;
00481 for (next_pgno = NEXT_PGNO(hcp->page); next_pgno != PGNO_INVALID;
00482 next_pgno = NEXT_PGNO(next_pagep)) {
00483 if (next_pagep != NULL &&
00484 (ret = CDB___ham_put_page(dbp, next_pagep, 0)) != 0)
00485 return (ret);
00486 
00487 if ((ret =
00488 CDB___ham_get_page(dbp, next_pgno, &next_pagep)) != 0)
00489 return (ret);
00490 
00491 if (P_FREESPACE(next_pagep) >= new_datalen)
00492 break;
00493 }
00494 
00495 /* No more pages, add one. */
00496 if (next_pagep == NULL && (ret = CDB___ham_add_ovflpage(dbc,
00497 hcp->page, 0, &next_pagep)) != 0)
00498 return (ret);
00499 
00500 /* Add new page at the end of the chain. */
00501 if (P_FREESPACE(next_pagep) < new_datalen && (ret =
00502 CDB___ham_add_ovflpage(dbc, next_pagep, 1, &next_pagep)) != 0) {
00503 (void)CDB___ham_put_page(dbp, next_pagep, 0);
00504 return (ret);
00505 }
00506 
00507 /* Copy the item to the new page. */
00508 if (DB_LOGGING(dbc)) {
00509 rectype = PUTPAIR;
00510 k.flags = 0;
00511 d.flags = 0;
00512 if (HPAGE_PTYPE(
00513 H_PAIRKEY(hcp->page, hcp->indx)) == H_OFFPAGE) {
00514 rectype |= PAIR_KEYMASK;
00515 k.data = H_PAIRKEY(hcp->page, hcp->indx);
00516 k.size = HOFFPAGE_SIZE;
00517 } else {
00518 k.data =
00519 HKEYDATA_DATA(H_PAIRKEY(hcp->page, hcp->indx));
00520 k.size = LEN_HKEY(hcp->page, dbp->pgsize, hcp->indx);
00521 }
00522 
00523 if (HPAGE_PTYPE(hk) == H_OFFPAGE) {
00524 rectype |= PAIR_DATAMASK;
00525 d.data = H_PAIRDATA(hcp->page, hcp->indx);
00526 d.size = HOFFPAGE_SIZE;
00527 } else {
00528 if (HPAGE_PTYPE(H_PAIRDATA(hcp->page, hcp->indx))
00529 == H_DUPLICATE)
00530 rectype |= PAIR_DUPMASK;
00531 d.data =
00532 HKEYDATA_DATA(H_PAIRDATA(hcp->page, hcp->indx));
00533 d.size = LEN_HDATA(hcp->page, dbp->pgsize, hcp->indx);
00534 }
00535 
00536 if ((ret = CDB___ham_insdel_log(dbp->dbenv,
00537 dbc->txn, &new_lsn, 0, rectype,
00538 dbp->log_fileid, PGNO(next_pagep),
00539 (u_int32_t)NUM_ENT(next_pagep), &LSN(next_pagep),
00540 &k, &d)) != 0)
00541 return (ret);
00542 
00543 /* Move lsn onto page. */
00544 LSN(next_pagep) = new_lsn; /* Structure assignment. */
00545 }
00546 
00547 CDB___ham_copy_item(dbp->pgsize,
00548 hcp->page, H_KEYINDEX(hcp->indx), next_pagep);
00549 CDB___ham_copy_item(dbp->pgsize,
00550 hcp->page, H_DATAINDEX(hcp->indx), next_pagep);
00551 
00552 /* Update all cursors that used to point to this item. */
00553 CDB___ham_c_chgpg(dbc, PGNO(hcp->page), H_KEYINDEX(hcp->indx),
00554 PGNO(next_pagep), NUM_ENT(next_pagep) - 2);
00555 
00556 /* Now delete the pair from the current page. */
00557 ret = CDB___ham_del_pair(dbc, 0);
00558 
00559 /*
00560  * CDB___ham_del_pair decremented nelem. This is incorrect; we
00561  * manually copied the element elsewhere, so the total number
00562  * of elements hasn't changed. Increment it again.
00563  */
00564 if (!STD_LOCKING(dbc))
00565 hcp->hdr->nelem++;
00566 
00567 (void)CDB___ham_put_page(dbp, hcp->page, 1);
00568 hcp->page = next_pagep;
00569 hcp->pgno = PGNO(hcp->page);
00570 hcp->indx = NUM_ENT(hcp->page) - 2;
00571 F_SET(hcp, H_EXPAND);
00572 return (ret);
00573 }
00574 
00575 /*
00576  * CDB___ham_move_offpage --
00577  * Replace an onpage set of duplicates with the OFFDUP structure
00578  * that references the duplicate page.
00579  *
00580  * XXX
00581  * This is really just a special case of __onpage_replace; we should
00582  * probably combine them.
00583  *
00584  * PUBLIC: void CDB___ham_move_offpage __P((DBC *, PAGE *, u_int32_t, db_pgno_t));
00585  */
00586 void
00587 CDB___ham_move_offpage(dbc, pagep, ndx, pgno)
00588 DBC *dbc;
00589 PAGE *pagep;
00590 u_int32_t ndx;
00591 db_pgno_t pgno;
00592 {
00593 DB *dbp;
00594 HASH_CURSOR *hcp;
00595 DBT new_dbt;
00596 DBT old_dbt;
00597 HOFFDUP od;
00598 db_indx_t i;
00599 int32_t shrink;
00600 u_int8_t *src;
00601 
00602 dbp = dbc->dbp;
00603 hcp = (HASH_CURSOR *)dbc->internal;
00604 od.type = H_OFFDUP;
00605 UMRW(od.unused[0]);
00606 UMRW(od.unused[1]);
00607 UMRW(od.unused[2]);
00608 od.pgno = pgno;
00609 
00610 if (DB_LOGGING(dbc)) {
00611 new_dbt.data = &od;
00612 new_dbt.size = HOFFDUP_SIZE;
00613 old_dbt.data = P_ENTRY(pagep, ndx);
00614 old_dbt.size = LEN_HITEM(pagep, dbp->pgsize, ndx);
00615 (void)CDB___ham_replace_log(dbp->dbenv,
00616 dbc->txn, &LSN(pagep), 0, dbp->log_fileid,
00617 PGNO(pagep), (u_int32_t)ndx, &LSN(pagep), -1,
00618 &old_dbt, &new_dbt, 0);
00619 }
00620 
00621 shrink = LEN_HITEM(pagep, dbp->pgsize, ndx) - HOFFDUP_SIZE;
00622 
00623 if (shrink != 0) {
00624 /* Copy data. */
00625 src = (u_int8_t *)(pagep) + HOFFSET(pagep);
00626 memmove(src + shrink, src, pagep->inp[ndx] - HOFFSET(pagep));
00627 HOFFSET(pagep) += shrink;
00628 
00629 /* Update index table. */
00630 for (i = ndx; i < NUM_ENT(pagep); i++)
00631 pagep->inp[i] += shrink;
00632 }
00633 
00634 /* Now copy the offdup entry onto the page. */
00635 memcpy(P_ENTRY(pagep, ndx), &od, HOFFDUP_SIZE);
00636 }
00637 
00638 /*
00639  * CDB___ham_dsearch:
00640  * Locate a particular duplicate in a duplicate set. Make sure that
00641  * we exit with the cursor set appropriately.
00642  *
00643  * PUBLIC: void CDB___ham_dsearch __P((DBC *, DBT *, u_int32_t *, int *));
00644  */
00645 void
00646 CDB___ham_dsearch(dbc, dbt, offp, cmpp)
00647 DBC *dbc;
00648 DBT *dbt;
00649 u_int32_t *offp;
00650 int *cmpp;
00651 {
00652 DB *dbp;
00653 HASH_CURSOR *hcp;
00654 DBT cur;
00655 db_indx_t i, len;
00656 int (*func) __P((const DBT *, const DBT *));
00657 u_int8_t *data;
00658 
00659 dbp = dbc->dbp;
00660 hcp = (HASH_CURSOR *)dbc->internal;
00661 if (dbp->dup_compare == NULL)
00662 func = CDB___bam_defcmp;
00663 else
00664 func = dbp->dup_compare;
00665 
00666 i = F_ISSET(hcp, H_CONTINUE) ? hcp->dup_off: 0;
00667 data = HKEYDATA_DATA(H_PAIRDATA(hcp->page, hcp->indx)) + i;
00668 hcp->dup_tlen = LEN_HDATA(hcp->page, dbp->pgsize, hcp->indx);
00669 while (i < hcp->dup_tlen) {
00670 memcpy(&len, data, sizeof(db_indx_t));
00671 data += sizeof(db_indx_t);
00672 cur.data = data;
00673 cur.size = (u_int32_t)len;
00674 *cmpp = func(dbt, &cur);
00675 if (*cmpp == 0 || (*cmpp < 0 && dbp->dup_compare != NULL))
00676 break;
00677 i += len + 2 * sizeof(db_indx_t);
00678 data += len + sizeof(db_indx_t);
00679 }
00680 *offp = i;
00681 hcp->dup_off = i;
00682 hcp->dup_len = len;
00683 F_SET(hcp, H_ISDUP);
00684 }
00685 
00686 #ifdef DEBUG
00687 /*
00688  * CDB___ham_cprint --
00689  * Display the current cursor list.
00690  *
00691  * PUBLIC: int CDB___ham_cprint __P((DB *));
00692  */
00693 int
00694 CDB___ham_cprint(dbp)
00695 DB *dbp;
00696 {
00697 HASH_CURSOR *cp;
00698 DBC *dbc;
00699 
00700 MUTEX_THREAD_LOCK(dbp->mutexp);
00701 for (dbc = TAILQ_FIRST(&dbp->active_queue);
00702 dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
00703 cp = (HASH_CURSOR *)dbc->internal;
00704 fprintf(stderr, "%#0lx->%#0lx: page: %lu index: %lu",
00705 P_TO_ULONG(dbc), P_TO_ULONG(cp), (u_long)cp->pgno,
00706 (u_long)cp->indx);
00707 if (F_ISSET(cp, H_DELETED))
00708 fprintf(stderr, " (deleted)");
00709 fprintf(stderr, "\n");
00710 }
00711 MUTEX_THREAD_UNLOCK(dbp->mutexp);
00712 
00713 return (0);
00714 }
00715 #endif /* DEBUG */
00716 
00717 /*
00718  * __ham_dcursor --
00719  *
00720  * Create an off page duplicate cursor for this cursor.
00721  */
00722 static int
00723 __ham_dcursor(dbc, pgno, indx)
00724 DBC *dbc;
00725 db_pgno_t pgno;
00726 u_int32_t indx;
00727 {
00728 DB *dbp;
00729 DBC *dbc_nopd;
00730 HASH_CURSOR *hcp;
00731 BTREE_CURSOR *dcp;
00732 int ret;
00733 
00734 dbp = dbc->dbp;
00735 
00736 dbc_nopd = NULL;
00737 if ((ret = CDB___db_icursor(dbp, dbc->txn,
00738 dbp->dup_compare == NULL ? DB_RECNO : DB_BTREE,
00739 pgno, 1, &dbc_nopd)) != 0)
00740 return (ret);
00741 
00742 dcp = (BTREE_CURSOR *)dbc_nopd->internal;
00743 dcp->pgno = pgno;
00744 dcp->indx = indx;
00745 
00746 if (dbp->dup_compare == NULL) {
00747 /*
00748  * Converting to off-page Recno trees is tricky. The
00749  * record number for the cursor is the index + 1 (to
00750  * convert to 1-based record numbers).
00751  */
00752 dcp->recno = indx + 1;
00753 }
00754 
00755 /*
00756  * Transfer the deleted flag from the top-level cursor to the
00757  * created one.
00758  */
00759 hcp = (HASH_CURSOR *)dbc->internal;
00760 if (F_ISSET(hcp, H_DELETED)) {
00761 F_SET(dcp, C_DELETED);
00762 F_CLR(hcp, H_DELETED);
00763 }
00764 
00765 /* Stack the cursors and reset the initial cursor's index. */
00766 hcp->opd = dbc_nopd;
00767 
00768 return (0);
00769 }

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