db.1.85/btree/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  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  */
  36
  37 #if defined(LIBC_SCCS) && !defined(lint)
  38 static char sccsid[] = "@(#)bt_put.c    8.8 (Berkeley) 7/26/94";
  39 #endif /* LIBC_SCCS and not lint */
  40
  41 #include <sys/types.h>
  42
  43 #include <errno.h>
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46 #include <string.h>
  47
  48 #include <db.h>
  49 #include "btree.h"
  50
  51 static EPG *bt_fast __P((BTREE *, const DBT *, const DBT *, int *));
  52
  53 /*
  54  * __BT_PUT -- Add a btree item to the tree.
  55  *
  56  * Parameters:
  57  *      dbp:    pointer to access method
  58  *      key:    key
  59  *      data:   data
  60  *      flag:   R_NOOVERWRITE
  61  *
  62  * Returns:
  63  *      RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key is already in the
  64  *      tree and R_NOOVERWRITE specified.
  65  */
  66 int
  67 __bt_put(dbp, key, data, flags)
  68         const DB *dbp;
  69         DBT *key;
  70         const DBT *data;
  71         u_int flags;
  72 {
  73         BTREE *t;
  74         DBT tkey, tdata;
  75         EPG *e;
  76         PAGE *h;
  77         indx_t index, nxtindex;
  78         pgno_t pg;
  79         u_int32_t nbytes;
  80         int dflags, exact, status;
  81         char *dest, db[NOVFLSIZE], kb[NOVFLSIZE];
  82
  83         t = dbp->internal;
  84
  85         /* Toss any page pinned across calls. */
  86         if (t->bt_pinned != NULL) {
  87                 mpool_put(t->bt_mp, t->bt_pinned, 0);
  88                 t->bt_pinned = NULL;
  89         }
  90
  91         /* Check for change to a read-only tree. */
  92         if (F_ISSET(t, B_RDONLY)) {
  93                 errno = EPERM;
  94                 return (RET_ERROR);
  95         }
  96
  97         switch (flags) {
  98         case 0:
  99         case R_NOOVERWRITE:
 100                 break;
 101         case R_CURSOR:
 102                 /*
 103                  * If flags is R_CURSOR, put the cursor.  Must already
 104                  * have started a scan and not have already deleted it.
 105                  */
 106                 if (F_ISSET(&t->bt_cursor, CURS_INIT) &&
 107                     !F_ISSET(&t->bt_cursor,
 108                         CURS_ACQUIRE | CURS_AFTER | CURS_BEFORE))
 109                         break;
 110                 /* FALLTHROUGH */
 111         default:
 112                 errno = EINVAL;
 113                 return (RET_ERROR);
 114         }
 115
 116         /*
 117          * If the key/data pair won't fit on a page, store it on overflow
 118          * pages.  Only put the key on the overflow page if the pair are
 119          * still too big after moving the data to an overflow page.
 120          *
 121          * XXX
 122          * If the insert fails later on, the overflow pages aren't recovered.
 123          */
 124         dflags = 0;
 125         if (key->size + data->size > t->bt_ovflsize) {
 126                 if (key->size > t->bt_ovflsize) {
 127 storekey:               if (__ovfl_put(t, key, &pg) == RET_ERROR)
 128                                 return (RET_ERROR);
 129                         tkey.data = kb;
 130                         tkey.size = NOVFLSIZE;
 131                         memmove(kb, &pg, sizeof(pgno_t));
 132                         memmove(kb + sizeof(pgno_t),
 133                             &key->size, sizeof(u_int32_t));
 134                         dflags |= P_BIGKEY;
 135                         key = &tkey;
 136                 }
 137                 if (key->size + data->size > t->bt_ovflsize) {
 138                         if (__ovfl_put(t, data, &pg) == RET_ERROR)
 139                                 return (RET_ERROR);
 140                         tdata.data = db;
 141                         tdata.size = NOVFLSIZE;
 142                         memmove(db, &pg, sizeof(pgno_t));
 143                         memmove(db + sizeof(pgno_t),
 144                             &data->size, sizeof(u_int32_t));
 145                         dflags |= P_BIGDATA;
 146                         data = &tdata;
 147                 }
 148                 if (key->size + data->size > t->bt_ovflsize)
 149                         goto storekey;
 150         }
 151
 152         /* Replace the cursor. */
 153         if (flags == R_CURSOR) {
 154                 if ((h = mpool_get(t->bt_mp, t->bt_cursor.pg.pgno, 0)) == NULL)
 155                         return (RET_ERROR);
 156                 index = t->bt_cursor.pg.index;
 157                 goto delete;
 158         }
 159
 160         /*
 161          * Find the key to delete, or, the location at which to insert.
 162          * Bt_fast and __bt_search both pin the returned page.
 163          */
 164         if (t->bt_order == NOT || (e = bt_fast(t, key, data, &exact)) == NULL)
 165                 if ((e = __bt_search(t, key, &exact)) == NULL)
 166                         return (RET_ERROR);
 167         h = e->page;
 168         index = e->index;
 169
 170         /*
 171          * Add the key/data pair to the tree.  If an identical key is already
 172          * in the tree, and R_NOOVERWRITE is set, an error is returned.  If
 173          * R_NOOVERWRITE is not set, the key is either added (if duplicates are
 174          * permitted) or an error is returned.
 175          */
 176         switch (flags) {
 177         case R_NOOVERWRITE:
 178                 if (!exact)
 179                         break;
 180                 mpool_put(t->bt_mp, h, 0);
 181                 return (RET_SPECIAL);
 182         default:
 183                 if (!exact || !F_ISSET(t, B_NODUPS))
 184                         break;
 185                 /*
 186                  * !!!
 187                  * Note, the delete may empty the page, so we need to put a
 188                  * new entry into the page immediately.
 189                  */
 190 delete:         if (__bt_dleaf(t, key, h, index) == RET_ERROR) {
 191                         mpool_put(t->bt_mp, h, 0);
 192                         return (RET_ERROR);
 193                 }
 194                 break;
 195         }
 196
 197         /*
 198          * If not enough room, or the user has put a ceiling on the number of
 199          * keys permitted in the page, split the page.  The split code will
 200          * insert the key and data and unpin the current page.  If inserting
 201          * into the offset array, shift the pointers up.
 202          */
 203         nbytes = NBLEAFDBT(key->size, data->size);
 204         if (h->upper - h->lower < nbytes + sizeof(indx_t)) {
 205                 if ((status = __bt_split(t, h, key,
 206                     data, dflags, nbytes, index)) != RET_SUCCESS)
 207                         return (status);
 208                 goto success;
 209         }
 210
 211         if (index < (nxtindex = NEXTINDEX(h)))
 212                 memmove(h->linp + index + 1, h->linp + index,
 213                     (nxtindex - index) * sizeof(indx_t));
 214         h->lower += sizeof(indx_t);
 215
 216         h->linp[index] = h->upper -= nbytes;
 217         dest = (char *)h + h->upper;
 218         WR_BLEAF(dest, key, data, dflags);
 219
 220         /* If the cursor is on this page, adjust it as necessary. */
 221         if (F_ISSET(&t->bt_cursor, CURS_INIT) &&
 222             !F_ISSET(&t->bt_cursor, CURS_ACQUIRE) &&
 223             t->bt_cursor.pg.pgno == h->pgno && t->bt_cursor.pg.index >= index)
 224                 ++t->bt_cursor.pg.index;
 225
 226         if (t->bt_order == NOT)
 227                 if (h->nextpg == P_INVALID) {
 228                         if (index == NEXTINDEX(h) - 1) {
 229                                 t->bt_order = FORWARD;
 230                                 t->bt_last.index = index;
 231                                 t->bt_last.pgno = h->pgno;
 232                         }
 233                 } else if (h->prevpg == P_INVALID) {
 234                         if (index == 0) {
 235                                 t->bt_order = BACK;
 236                                 t->bt_last.index = 0;
 237                                 t->bt_last.pgno = h->pgno;
 238                         }
 239                 }
 240
 241         mpool_put(t->bt_mp, h, MPOOL_DIRTY);
 242
 243 success:
 244         if (flags == R_SETCURSOR)
 245                 __bt_setcur(t, e->page->pgno, e->index);
 246
 247         F_SET(t, B_MODIFIED);
 248         return (RET_SUCCESS);
 249 }
 250
 251 #ifdef STATISTICS
 252 u_long bt_cache_hit, bt_cache_miss;
 253 #endif
 254
 255 /*
 256  * BT_FAST -- Do a quick check for sorted data.
 257  *
 258  * Parameters:
 259  *      t:      tree
 260  *      key:    key to insert
 261  *
 262  * Returns:
 263  *      EPG for new record or NULL if not found.
 264  */
 265 static EPG *
 266 bt_fast(t, key, data, exactp)
 267         BTREE *t;
 268         const DBT *key, *data;
 269         int *exactp;
 270 {
 271         PAGE *h;
 272         u_int32_t nbytes;
 273         int cmp;
 274
 275         if ((h = mpool_get(t->bt_mp, t->bt_last.pgno, 0)) == NULL) {
 276                 t->bt_order = NOT;
 277                 return (NULL);
 278         }
 279         t->bt_cur.page = h;
 280         t->bt_cur.index = t->bt_last.index;
 281
 282         /*
 283          * If won't fit in this page or have too many keys in this page,
 284          * have to search to get split stack.
 285          */
 286         nbytes = NBLEAFDBT(key->size, data->size);
 287         if (h->upper - h->lower < nbytes + sizeof(indx_t))
 288                 goto miss;
 289
 290         if (t->bt_order == FORWARD) {
 291                 if (t->bt_cur.page->nextpg != P_INVALID)
 292                         goto miss;
 293                 if (t->bt_cur.index != NEXTINDEX(h) - 1)
 294                         goto miss;
 295                 if ((cmp = __bt_cmp(t, key, &t->bt_cur)) < 0)
 296                         goto miss;
 297                 t->bt_last.index = cmp ? ++t->bt_cur.index : t->bt_cur.index;
 298         } else {
 299                 if (t->bt_cur.page->prevpg != P_INVALID)
 300                         goto miss;
 301                 if (t->bt_cur.index != 0)
 302                         goto miss;
 303                 if ((cmp = __bt_cmp(t, key, &t->bt_cur)) > 0)
 304                         goto miss;
 305                 t->bt_last.index = 0;
 306         }
 307         *exactp = cmp == 0;
 308 #ifdef STATISTICS
 309         ++bt_cache_hit;
 310 #endif
 311         return (&t->bt_cur);
 312
 313 miss:
 314 #ifdef STATISTICS
 315         ++bt_cache_miss;
 316 #endif
 317         t->bt_order = NOT;
 318         mpool_put(t->bt_mp, h, 0);
 319         return (NULL);
 320 }