lib/libc/db/btree/bt_put.c

   1 /*      $NetBSD: bt_put.c,v 1.20 2011/06/26 22:20:31 christos Exp $     */
   2
   3 /*-
   4  * Copyright (c) 1990, 1993, 1994
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Mike Olson.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #if HAVE_NBTOOL_CONFIG_H
  36 #include "nbtool_config.h"
  37 #endif
  38
  39 #include <sys/cdefs.h>
  40 __RCSID("$NetBSD: bt_put.c,v 1.20 2011/06/26 22:20:31 christos Exp $");
  41
  42 #include "namespace.h"
  43 #include <sys/types.h>
  44
  45 #include <assert.h>
  46 #include <errno.h>
  47 #include <stdio.h>
  48 #include <stdlib.h>
  49 #include <string.h>
  50
  51 #include <db.h>
  52 #include "btree.h"
  53
  54 static EPG *bt_fast(BTREE *, const DBT *, const DBT *, int *);
  55
  56 /*
  57  * __BT_PUT -- Add a btree item to the tree.
  58  *
  59  * Parameters:
  60  *      dbp:    pointer to access method
  61  *      key:    key
  62  *      data:   data
  63  *      flag:   R_NOOVERWRITE
  64  *
  65  * Returns:
  66  *      RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key is already in the
  67  *      tree and R_NOOVERWRITE specified.
  68  */
  69 int
  70 __bt_put(const DB *dbp, DBT *key, const DBT *data, u_int flags)
  71 {
  72         BTREE *t;
  73         DBT tkey, tdata;
  74         EPG *e = NULL; /* pacify gcc */
  75         PAGE *h;
  76         indx_t idx, nxtindex;
  77         pgno_t pg;
  78         uint32_t nbytes, temp;
  79         int dflags, exact, status;
  80         char *dest, db[NOVFLSIZE], kb[NOVFLSIZE];
  81
  82         t = dbp->internal;
  83
  84         /* Toss any page pinned across calls. */
  85         if (t->bt_pinned != NULL) {
  86                 mpool_put(t->bt_mp, t->bt_pinned, 0);
  87                 t->bt_pinned = NULL;
  88         }
  89
  90         /* Check for change to a read-only tree. */
  91         if (F_ISSET(t, B_RDONLY)) {
  92                 errno = EPERM;
  93                 return (RET_ERROR);
  94         }
  95
  96         switch (flags) {
  97         case 0:
  98         case R_NOOVERWRITE:
  99                 break;
 100         case R_CURSOR:
 101                 /*
 102                  * If flags is R_CURSOR, put the cursor.  Must already
 103                  * have started a scan and not have already deleted it.
 104                  */
 105                 if (F_ISSET(&t->bt_cursor, CURS_INIT) &&
 106                     !F_ISSET(&t->bt_cursor,
 107                         CURS_ACQUIRE | CURS_AFTER | CURS_BEFORE))
 108                         break;
 109                 /* FALLTHROUGH */
 110         default:
 111                 errno = EINVAL;
 112                 return (RET_ERROR);
 113         }
 114
 115         /*
 116          * If the key/data pair won't fit on a page, store it on overflow
 117          * pages.  Only put the key on the overflow page if the pair are
 118          * still too big after moving the data to an overflow page.
 119          *
 120          * XXX
 121          * If the insert fails later on, the overflow pages aren't recovered.
 122          */
 123         dflags = 0;
 124         if (key->size + data->size > t->bt_ovflsize) {
 125                 if (key->size > t->bt_ovflsize) {
 126 storekey:               if (__ovfl_put(t, key, &pg) == RET_ERROR)
 127                                 return (RET_ERROR);
 128                         tkey.data = kb;
 129                         tkey.size = NOVFLSIZE;
 130                         memmove(kb, &pg, sizeof(pg));
 131                         memmove(kb + sizeof(pgno_t),
 132                             &key->size, sizeof(uint32_t));
 133                         dflags |= P_BIGKEY;
 134                         key = &tkey;
 135                 }
 136                 if (key->size + data->size > t->bt_ovflsize) {
 137                         if (__ovfl_put(t, data, &pg) == RET_ERROR)
 138                                 return (RET_ERROR);
 139                         tdata.data = db;
 140                         tdata.size = NOVFLSIZE;
 141                         memmove(db, &pg, sizeof(pg));
 142                         _DBFIT(data->size, uint32_t);
 143                         temp = (uint32_t)data->size;
 144                         (void)memmove(db + sizeof(pgno_t),
 145                             &temp, sizeof(uint32_t));
 146                         dflags |= P_BIGDATA;
 147                         data = &tdata;
 148                 }
 149                 if (key->size + data->size > t->bt_ovflsize)
 150                         goto storekey;
 151         }
 152
 153         /* Replace the cursor. */
 154         if (flags == R_CURSOR) {
 155                 if ((h = mpool_get(t->bt_mp, t->bt_cursor.pg.pgno, 0)) == NULL)
 156                         return (RET_ERROR);
 157                 idx = t->bt_cursor.pg.index;
 158                 goto delete;
 159         }
 160
 161         /*
 162          * Find the key to delete, or, the location at which to insert.
 163          * Bt_fast and __bt_search both pin the returned page.
 164          */
 165         if (t->bt_order == NOT || (e = bt_fast(t, key, data, &exact)) == NULL)
 166                 if ((e = __bt_search(t, key, &exact)) == NULL)
 167                         return (RET_ERROR);
 168         h = e->page;
 169         idx = e->index;
 170
 171         /*
 172          * Add the key/data pair to the tree.  If an identical key is already
 173          * in the tree, and R_NOOVERWRITE is set, an error is returned.  If
 174          * R_NOOVERWRITE is not set, the key is either added (if duplicates are
 175          * permitted) or an error is returned.
 176          */
 177         switch (flags) {
 178         case R_NOOVERWRITE:
 179                 if (!exact)
 180                         break;
 181                 mpool_put(t->bt_mp, h, 0);
 182                 return (RET_SPECIAL);
 183         default:
 184                 if (!exact || !F_ISSET(t, B_NODUPS))
 185                         break;
 186                 /*
 187                  * !!!
 188                  * Note, the delete may empty the page, so we need to put a
 189                  * new entry into the page immediately.
 190                  */
 191 delete:         if (__bt_dleaf(t, key, h, (u_int)idx) == RET_ERROR) {
 192                         mpool_put(t->bt_mp, h, 0);
 193                         return (RET_ERROR);
 194                 }
 195                 break;
 196         }
 197
 198         /*
 199          * If not enough room, or the user has put a ceiling on the number of
 200          * keys permitted in the page, split the page.  The split code will
 201          * insert the key and data and unpin the current page.  If inserting
 202          * into the offset array, shift the pointers up.
 203          */
 204         nbytes = NBLEAFDBT(key->size, data->size);
 205         if ((uint32_t)h->upper - (uint32_t)h->lower < nbytes + sizeof(indx_t)) {
 206                 if ((status = __bt_split(t, h, key,
 207                     data, dflags, nbytes, (u_int)idx)) != RET_SUCCESS)
 208                         return (status);
 209                 goto success;
 210         }
 211
 212         if (idx < (nxtindex = NEXTINDEX(h)))
 213                 memmove(h->linp + idx + 1, h->linp + idx,
 214                     (nxtindex - idx) * sizeof(indx_t));
 215         h->lower += sizeof(indx_t);
 216
 217         h->linp[idx] = h->upper -= nbytes;
 218         dest = (char *)(void *)h + h->upper;
 219         WR_BLEAF(dest, key, data, dflags);
 220
 221         /* If the cursor is on this page, adjust it as necessary. */
 222         if (F_ISSET(&t->bt_cursor, CURS_INIT) &&
 223             !F_ISSET(&t->bt_cursor, CURS_ACQUIRE) &&
 224             t->bt_cursor.pg.pgno == h->pgno && t->bt_cursor.pg.index >= idx)
 225                 ++t->bt_cursor.pg.index;
 226
 227         if (t->bt_order == NOT) {
 228                 if (h->nextpg == P_INVALID) {
 229                         if (idx == NEXTINDEX(h) - 1) {
 230                                 t->bt_order = FORWARD;
 231                                 t->bt_last.index = idx;
 232                                 t->bt_last.pgno = h->pgno;
 233                         }
 234                 } else if (h->prevpg == P_INVALID) {
 235                         if (idx == 0) {
 236                                 t->bt_order = BACK;
 237                                 t->bt_last.index = 0;
 238                                 t->bt_last.pgno = h->pgno;
 239                         }
 240                 }
 241         }
 242
 243         mpool_put(t->bt_mp, h, MPOOL_DIRTY);
 244
 245 success:
 246         if (flags == R_SETCURSOR)
 247                 __bt_setcur(t, e->page->pgno, (u_int)e->index);
 248
 249         F_SET(t, B_MODIFIED);
 250         return (RET_SUCCESS);
 251 }
 252
 253 #ifdef STATISTICS
 254 unsigned long bt_cache_hit, bt_cache_miss;
 255 #endif
 256
 257 /*
 258  * BT_FAST -- Do a quick check for sorted data.
 259  *
 260  * Parameters:
 261  *      t:      tree
 262  *      key:    key to insert
 263  *
 264  * Returns:
 265  *      EPG for new record or NULL if not found.
 266  */
 267 static EPG *
 268 bt_fast(BTREE *t, const DBT *key, const DBT *data, int *exactp)
 269 {
 270         PAGE *h;
 271         uint32_t nbytes;
 272         int cmp;
 273
 274         if ((h = mpool_get(t->bt_mp, t->bt_last.pgno, 0)) == NULL) {
 275                 t->bt_order = NOT;
 276                 return (NULL);
 277         }
 278         t->bt_cur.page = h;
 279         t->bt_cur.index = t->bt_last.index;
 280
 281         /*
 282          * If won't fit in this page or have too many keys in this page,
 283          * have to search to get split stack.
 284          */
 285         nbytes = NBLEAFDBT(key->size, data->size);
 286         if ((uint32_t)h->upper - (uint32_t)h->lower < nbytes + sizeof(indx_t))
 287                 goto miss;
 288
 289         if (t->bt_order == FORWARD) {
 290                 if (t->bt_cur.page->nextpg != P_INVALID)
 291                         goto miss;
 292                 if (t->bt_cur.index != NEXTINDEX(h) - 1)
 293                         goto miss;
 294                 if ((cmp = __bt_cmp(t, key, &t->bt_cur)) < 0)
 295                         goto miss;
 296                 t->bt_last.index = cmp ? ++t->bt_cur.index : t->bt_cur.index;
 297         } else {
 298                 if (t->bt_cur.page->prevpg != P_INVALID)
 299                         goto miss;
 300                 if (t->bt_cur.index != 0)
 301                         goto miss;
 302                 if ((cmp = __bt_cmp(t, key, &t->bt_cur)) > 0)
 303                         goto miss;
 304                 t->bt_last.index = 0;
 305         }
 306         *exactp = cmp == 0;
 307 #ifdef STATISTICS
 308         ++bt_cache_hit;
 309 #endif
 310         return (&t->bt_cur);
 311
 312 miss:
 313 #ifdef STATISTICS
 314         ++bt_cache_miss;
 315 #endif
 316         t->bt_order = NOT;
 317         mpool_put(t->bt_mp, h, 0);
 318         return (NULL);
 319 }