db/btree/FreeBSD/bt_put.c

   1 /*-
   2  * Copyright (c) 1990, 1993, 1994
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Mike Olson.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 4. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 static char sccsid[] = "@(#)bt_put.c    8.8 (Berkeley) 7/26/94";
  35 #endif /* LIBC_SCCS and not lint */
  36 #include <sys/cdefs.h>
  37 __FBSDID("$FreeBSD: src/lib/libc/db/btree/bt_put.c,v 1.9 2009/03/28 05:45:29 delphij Exp $");
  38
  39 #include <sys/types.h>
  40
  41 #include <errno.h>
  42 #include <stdio.h>
  43 #include <stdlib.h>
  44 #include <string.h>
  45
  46 #include <db.h>
  47 #include "btree.h"
  48
  49 static EPG *bt_fast(BTREE *, const DBT *, const DBT *, int *);
  50
  51 /*
  52  * __BT_PUT -- Add a btree item to the tree.
  53  *
  54  * Parameters:
  55  *      dbp:    pointer to access method
  56  *      key:    key
  57  *      data:   data
  58  *      flag:   R_NOOVERWRITE
  59  *
  60  * Returns:
  61  *      RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key is already in the
  62  *      tree and R_NOOVERWRITE specified.
  63  */
  64 int
  65 __bt_put(const DB *dbp, DBT *key, const DBT *data, u_int flags)
  66 {
  67         BTREE *t;
  68         DBT tkey, tdata;
  69         EPG *e;
  70         PAGE *h;
  71         indx_t idx, nxtindex;
  72         pgno_t pg;
  73         u_int32_t nbytes, tmp;
  74         int dflags, exact, status;
  75         char *dest, db[NOVFLSIZE], kb[NOVFLSIZE];
  76
  77         t = dbp->internal;
  78
  79         /* Toss any page pinned across calls. */
  80         if (t->bt_pinned != NULL) {
  81                 mpool_put(t->bt_mp, t->bt_pinned, 0);
  82                 t->bt_pinned = NULL;
  83         }
  84
  85         /* Check for change to a read-only tree. */
  86         if (F_ISSET(t, B_RDONLY)) {
  87                 errno = EPERM;
  88                 return (RET_ERROR);
  89         }
  90
  91         switch (flags) {
  92         case 0:
  93         case R_NOOVERWRITE:
  94                 break;
  95         case R_CURSOR:
  96                 /*
  97                  * If flags is R_CURSOR, put the cursor.  Must already
  98                  * have started a scan and not have already deleted it.
  99                  */
 100                 if (F_ISSET(&t->bt_cursor, CURS_INIT) &&
 101                     !F_ISSET(&t->bt_cursor,
 102                         CURS_ACQUIRE | CURS_AFTER | CURS_BEFORE))
 103                         break;
 104                 /* FALLTHROUGH */
 105         default:
 106                 errno = EINVAL;
 107                 return (RET_ERROR);
 108         }
 109
 110         /*
 111          * If the key/data pair won't fit on a page, store it on overflow
 112          * pages.  Only put the key on the overflow page if the pair are
 113          * still too big after moving the data to an overflow page.
 114          *
 115          * XXX
 116          * If the insert fails later on, the overflow pages aren't recovered.
 117          */
 118         dflags = 0;
 119         if (key->size + data->size > t->bt_ovflsize) {
 120                 if (key->size > t->bt_ovflsize) {
 121 storekey:               if (__ovfl_put(t, key, &pg) == RET_ERROR)
 122                                 return (RET_ERROR);
 123                         tkey.data = kb;
 124                         tkey.size = NOVFLSIZE;
 125                         memmove(kb, &pg, sizeof(pgno_t));
 126                         tmp = key->size;
 127                         memmove(kb + sizeof(pgno_t),
 128                             &tmp, sizeof(u_int32_t));
 129                         dflags |= P_BIGKEY;
 130                         key = &tkey;
 131                 }
 132                 if (key->size + data->size > t->bt_ovflsize) {
 133                         if (__ovfl_put(t, data, &pg) == RET_ERROR)
 134                                 return (RET_ERROR);
 135                         tdata.data = db;
 136                         tdata.size = NOVFLSIZE;
 137                         memmove(db, &pg, sizeof(pgno_t));
 138                         tmp = data->size;
 139                         memmove(db + sizeof(pgno_t),
 140                             &tmp, sizeof(u_int32_t));
 141                         dflags |= P_BIGDATA;
 142                         data = &tdata;
 143                 }
 144                 if (key->size + data->size > t->bt_ovflsize)
 145                         goto storekey;
 146         }
 147
 148         /* Replace the cursor. */
 149         if (flags == R_CURSOR) {
 150                 if ((h = mpool_get(t->bt_mp, t->bt_cursor.pg.pgno, 0)) == NULL)
 151                         return (RET_ERROR);
 152                 idx = t->bt_cursor.pg.index;
 153                 goto delete;
 154         }
 155
 156         /*
 157          * Find the key to delete, or, the location at which to insert.
 158          * Bt_fast and __bt_search both pin the returned page.
 159          */
 160         if (t->bt_order == NOT || (e = bt_fast(t, key, data, &exact)) == NULL)
 161                 if ((e = __bt_search(t, key, &exact)) == NULL)
 162                         return (RET_ERROR);
 163         h = e->page;
 164         idx = e->index;
 165
 166         /*
 167          * Add the key/data pair to the tree.  If an identical key is already
 168          * in the tree, and R_NOOVERWRITE is set, an error is returned.  If
 169          * R_NOOVERWRITE is not set, the key is either added (if duplicates are
 170          * permitted) or an error is returned.
 171          */
 172         switch (flags) {
 173         case R_NOOVERWRITE:
 174                 if (!exact)
 175                         break;
 176                 mpool_put(t->bt_mp, h, 0);
 177                 return (RET_SPECIAL);
 178         default:
 179                 if (!exact || !F_ISSET(t, B_NODUPS))
 180                         break;
 181                 /*
 182                  * !!!
 183                  * Note, the delete may empty the page, so we need to put a
 184                  * new entry into the page immediately.
 185                  */
 186 delete:         if (__bt_dleaf(t, key, h, idx) == RET_ERROR) {
 187                         mpool_put(t->bt_mp, h, 0);
 188                         return (RET_ERROR);
 189                 }
 190                 break;
 191         }
 192
 193         /*
 194          * If not enough room, or the user has put a ceiling on the number of
 195          * keys permitted in the page, split the page.  The split code will
 196          * insert the key and data and unpin the current page.  If inserting
 197          * into the offset array, shift the pointers up.
 198          */
 199         nbytes = NBLEAFDBT(key->size, data->size);
 200         if ((u_int32_t)(h->upper - h->lower) < nbytes + sizeof(indx_t)) {
 201                 if ((status = __bt_split(t, h, key,
 202                     data, dflags, nbytes, idx)) != RET_SUCCESS)
 203                         return (status);
 204                 goto success;
 205         }
 206
 207         if (idx < (nxtindex = NEXTINDEX(h)))
 208                 memmove(h->linp + idx + 1, h->linp + idx,
 209                     (nxtindex - idx) * sizeof(indx_t));
 210         h->lower += sizeof(indx_t);
 211
 212         h->linp[idx] = h->upper -= nbytes;
 213         dest = (char *)h + h->upper;
 214         WR_BLEAF(dest, key, data, dflags);
 215
 216         /* If the cursor is on this page, adjust it as necessary. */
 217         if (F_ISSET(&t->bt_cursor, CURS_INIT) &&
 218             !F_ISSET(&t->bt_cursor, CURS_ACQUIRE) &&
 219             t->bt_cursor.pg.pgno == h->pgno && t->bt_cursor.pg.index >= idx)
 220                 ++t->bt_cursor.pg.index;
 221
 222         if (t->bt_order == NOT) {
 223                 if (h->nextpg == P_INVALID) {
 224                         if (idx == NEXTINDEX(h) - 1) {
 225                                 t->bt_order = FORWARD;
 226                                 t->bt_last.index = idx;
 227                                 t->bt_last.pgno = h->pgno;
 228                         }
 229                 } else if (h->prevpg == P_INVALID) {
 230                         if (idx == 0) {
 231                                 t->bt_order = BACK;
 232                                 t->bt_last.index = 0;
 233                                 t->bt_last.pgno = h->pgno;
 234                         }
 235                 }
 236         }
 237
 238         mpool_put(t->bt_mp, h, MPOOL_DIRTY);
 239
 240 success:
 241         if (flags == R_SETCURSOR)
 242                 __bt_setcur(t, e->page->pgno, e->index);
 243
 244         F_SET(t, B_MODIFIED);
 245         return (RET_SUCCESS);
 246 }
 247
 248 #ifdef STATISTICS
 249 u_long bt_cache_hit, bt_cache_miss;
 250 #endif
 251
 252 /*
 253  * BT_FAST -- Do a quick check for sorted data.
 254  *
 255  * Parameters:
 256  *      t:      tree
 257  *      key:    key to insert
 258  *
 259  * Returns:
 260  *      EPG for new record or NULL if not found.
 261  */
 262 static EPG *
 263 bt_fast(BTREE *t, const DBT *key, const DBT *data, int *exactp)
 264 {
 265         PAGE *h;
 266         u_int32_t nbytes;
 267         int cmp;
 268
 269         if ((h = mpool_get(t->bt_mp, t->bt_last.pgno, 0)) == NULL) {
 270                 t->bt_order = NOT;
 271                 return (NULL);
 272         }
 273         t->bt_cur.page = h;
 274         t->bt_cur.index = t->bt_last.index;
 275
 276         /*
 277          * If won't fit in this page or have too many keys in this page,
 278          * have to search to get split stack.
 279          */
 280         nbytes = NBLEAFDBT(key->size, data->size);
 281         if ((u_int32_t)(h->upper - h->lower) < nbytes + sizeof(indx_t))
 282                 goto miss;
 283
 284         if (t->bt_order == FORWARD) {
 285                 if (t->bt_cur.page->nextpg != P_INVALID)
 286                         goto miss;
 287                 if (t->bt_cur.index != NEXTINDEX(h) - 1)
 288                         goto miss;
 289                 if ((cmp = __bt_cmp(t, key, &t->bt_cur)) < 0)
 290                         goto miss;
 291                 t->bt_last.index = cmp ? ++t->bt_cur.index : t->bt_cur.index;
 292         } else {
 293                 if (t->bt_cur.page->prevpg != P_INVALID)
 294                         goto miss;
 295                 if (t->bt_cur.index != 0)
 296                         goto miss;
 297                 if ((cmp = __bt_cmp(t, key, &t->bt_cur)) > 0)
 298                         goto miss;
 299                 t->bt_last.index = 0;
 300         }
 301         *exactp = cmp == 0;
 302 #ifdef STATISTICS
 303         ++bt_cache_hit;
 304 #endif
 305         return (&t->bt_cur);
 306
 307 miss:
 308 #ifdef STATISTICS
 309         ++bt_cache_miss;
 310 #endif
 311         t->bt_order = NOT;
 312         mpool_put(t->bt_mp, h, 0);
 313         return (NULL);
 314 }