1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
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 #include <sys/types.h>
36
37 #include <errno.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41
42 #include <db.h>
43 #include "btree.h"
44
45 static EPG *bt_fast(BTREE *, const DBT *, const DBT *, int *);
46
47 /*
48 * __BT_PUT -- Add a btree item to the tree.
49 *
50 * Parameters:
51 * dbp: pointer to access method
52 * key: key
53 * data: data
54 * flag: R_NOOVERWRITE, R_SETCURSOR, R_CURSOR
55 *
56 * Returns:
57 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key is already in the
58 * tree and R_NOOVERWRITE specified.
59 */
60 int
__bt_put(const DB * dbp,DBT * key,const DBT * data,u_int flags)61 __bt_put(const DB *dbp, DBT *key, const DBT *data, u_int flags)
62 {
63 BTREE *t;
64 DBT tkey, tdata;
65 EPG *e;
66 PAGE *h;
67 indx_t idx, nxtindex;
68 pgno_t pg;
69 u_int32_t nbytes, tmp;
70 int dflags, exact, status;
71 char *dest, db[NOVFLSIZE], kb[NOVFLSIZE];
72
73 t = dbp->internal;
74
75 /* Toss any page pinned across calls. */
76 if (t->bt_pinned != NULL) {
77 mpool_put(t->bt_mp, t->bt_pinned, 0);
78 t->bt_pinned = NULL;
79 }
80
81 /* Check for change to a read-only tree. */
82 if (F_ISSET(t, B_RDONLY)) {
83 errno = EPERM;
84 return (RET_ERROR);
85 }
86
87 switch (flags) {
88 case 0:
89 case R_NOOVERWRITE:
90 case R_SETCURSOR:
91 break;
92 case R_CURSOR:
93 /*
94 * If flags is R_CURSOR, put the cursor. Must already
95 * have started a scan and not have already deleted it.
96 */
97 if (F_ISSET(&t->bt_cursor, CURS_INIT) &&
98 !F_ISSET(&t->bt_cursor,
99 CURS_ACQUIRE | CURS_AFTER | CURS_BEFORE))
100 break;
101 /* FALLTHROUGH */
102 default:
103 errno = EINVAL;
104 return (RET_ERROR);
105 }
106
107 /*
108 * If the key/data pair won't fit on a page, store it on overflow
109 * pages. Only put the key on the overflow page if the pair are
110 * still too big after moving the data to an overflow page.
111 *
112 * XXX
113 * If the insert fails later on, the overflow pages aren't recovered.
114 */
115 dflags = 0;
116 if (key->size + data->size > t->bt_ovflsize) {
117 if (key->size > t->bt_ovflsize) {
118 storekey: if (__ovfl_put(t, key, &pg) == RET_ERROR)
119 return (RET_ERROR);
120 tkey.data = kb;
121 tkey.size = NOVFLSIZE;
122 memmove(kb, &pg, sizeof(pgno_t));
123 tmp = key->size;
124 memmove(kb + sizeof(pgno_t),
125 &tmp, sizeof(u_int32_t));
126 dflags |= P_BIGKEY;
127 key = &tkey;
128 }
129 if (key->size + data->size > t->bt_ovflsize) {
130 if (__ovfl_put(t, data, &pg) == RET_ERROR)
131 return (RET_ERROR);
132 tdata.data = db;
133 tdata.size = NOVFLSIZE;
134 memmove(db, &pg, sizeof(pgno_t));
135 tmp = data->size;
136 memmove(db + sizeof(pgno_t),
137 &tmp, sizeof(u_int32_t));
138 dflags |= P_BIGDATA;
139 data = &tdata;
140 }
141 if (key->size + data->size > t->bt_ovflsize)
142 goto storekey;
143 }
144
145 /* Replace the cursor. */
146 if (flags == R_CURSOR) {
147 if ((h = mpool_get(t->bt_mp, t->bt_cursor.pg.pgno, 0)) == NULL)
148 return (RET_ERROR);
149 idx = t->bt_cursor.pg.index;
150 goto delete;
151 }
152
153 /*
154 * Find the key to delete, or, the location at which to insert.
155 * Bt_fast and __bt_search both pin the returned page.
156 */
157 if (t->bt_order == NOT || (e = bt_fast(t, key, data, &exact)) == NULL)
158 if ((e = __bt_search(t, key, &exact)) == NULL)
159 return (RET_ERROR);
160 h = e->page;
161 idx = e->index;
162
163 /*
164 * Add the key/data pair to the tree. If an identical key is already
165 * in the tree, and R_NOOVERWRITE is set, an error is returned. If
166 * R_NOOVERWRITE is not set, the key is either added (if duplicates are
167 * permitted) or an error is returned.
168 */
169 switch (flags) {
170 case R_NOOVERWRITE:
171 if (!exact)
172 break;
173 mpool_put(t->bt_mp, h, 0);
174 return (RET_SPECIAL);
175 default:
176 if (!exact || !F_ISSET(t, B_NODUPS))
177 break;
178 /*
179 * !!!
180 * Note, the delete may empty the page, so we need to put a
181 * new entry into the page immediately.
182 */
183 delete: if (__bt_dleaf(t, key, h, idx) == RET_ERROR) {
184 mpool_put(t->bt_mp, h, 0);
185 return (RET_ERROR);
186 }
187 break;
188 }
189
190 /*
191 * If not enough room, or the user has put a ceiling on the number of
192 * keys permitted in the page, split the page. The split code will
193 * insert the key and data and unpin the current page. If inserting
194 * into the offset array, shift the pointers up.
195 */
196 nbytes = NBLEAFDBT(key->size, data->size);
197 if ((u_int32_t)(h->upper - h->lower) < nbytes + sizeof(indx_t)) {
198 if ((status = __bt_split(t, h, key,
199 data, dflags, nbytes, idx)) != RET_SUCCESS)
200 return (status);
201 goto success;
202 }
203
204 if (idx < (nxtindex = NEXTINDEX(h)))
205 memmove(h->linp + idx + 1, h->linp + idx,
206 (nxtindex - idx) * sizeof(indx_t));
207 h->lower += sizeof(indx_t);
208
209 h->linp[idx] = h->upper -= nbytes;
210 dest = (char *)h + h->upper;
211 WR_BLEAF(dest, key, data, dflags);
212
213 /* If the cursor is on this page, adjust it as necessary. */
214 if (F_ISSET(&t->bt_cursor, CURS_INIT) &&
215 !F_ISSET(&t->bt_cursor, CURS_ACQUIRE) &&
216 t->bt_cursor.pg.pgno == h->pgno && t->bt_cursor.pg.index >= idx)
217 ++t->bt_cursor.pg.index;
218
219 if (t->bt_order == NOT) {
220 if (h->nextpg == P_INVALID) {
221 if (idx == NEXTINDEX(h) - 1) {
222 t->bt_order = FORWARD;
223 t->bt_last.index = idx;
224 t->bt_last.pgno = h->pgno;
225 }
226 } else if (h->prevpg == P_INVALID) {
227 if (idx == 0) {
228 t->bt_order = BACK;
229 t->bt_last.index = 0;
230 t->bt_last.pgno = h->pgno;
231 }
232 }
233 }
234
235 mpool_put(t->bt_mp, h, MPOOL_DIRTY);
236
237 success:
238 if (flags == R_SETCURSOR)
239 __bt_setcur(t, e->page->pgno, e->index);
240
241 F_SET(t, B_MODIFIED);
242 return (RET_SUCCESS);
243 }
244
245 #ifdef STATISTICS
246 u_long bt_cache_hit, bt_cache_miss;
247 #endif
248
249 /*
250 * BT_FAST -- Do a quick check for sorted data.
251 *
252 * Parameters:
253 * t: tree
254 * key: key to insert
255 *
256 * Returns:
257 * EPG for new record or NULL if not found.
258 */
259 static EPG *
bt_fast(BTREE * t,const DBT * key,const DBT * data,int * exactp)260 bt_fast(BTREE *t, const DBT *key, const DBT *data, int *exactp)
261 {
262 PAGE *h;
263 u_int32_t nbytes;
264 int cmp;
265
266 if ((h = mpool_get(t->bt_mp, t->bt_last.pgno, 0)) == NULL) {
267 t->bt_order = NOT;
268 return (NULL);
269 }
270 t->bt_cur.page = h;
271 t->bt_cur.index = t->bt_last.index;
272
273 /*
274 * If won't fit in this page or have too many keys in this page,
275 * have to search to get split stack.
276 */
277 nbytes = NBLEAFDBT(key->size, data->size);
278 if ((u_int32_t)(h->upper - h->lower) < nbytes + sizeof(indx_t))
279 goto miss;
280
281 if (t->bt_order == FORWARD) {
282 if (t->bt_cur.page->nextpg != P_INVALID)
283 goto miss;
284 if (t->bt_cur.index != NEXTINDEX(h) - 1)
285 goto miss;
286 if ((cmp = __bt_cmp(t, key, &t->bt_cur)) < 0)
287 goto miss;
288 t->bt_last.index = cmp ? ++t->bt_cur.index : t->bt_cur.index;
289 } else {
290 if (t->bt_cur.page->prevpg != P_INVALID)
291 goto miss;
292 if (t->bt_cur.index != 0)
293 goto miss;
294 if ((cmp = __bt_cmp(t, key, &t->bt_cur)) > 0)
295 goto miss;
296 t->bt_last.index = 0;
297 }
298 *exactp = cmp == 0;
299 #ifdef STATISTICS
300 ++bt_cache_hit;
301 #endif
302 return (&t->bt_cur);
303
304 miss:
305 #ifdef STATISTICS
306 ++bt_cache_miss;
307 #endif
308 t->bt_order = NOT;
309 mpool_put(t->bt_mp, h, 0);
310 return (NULL);
311 }
312