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 #if defined(LIBC_SCCS) && !defined(lint)
36 static char sccsid[] = "@(#)rec_delete.c 8.7 (Berkeley) 7/14/94";
37 #endif /* LIBC_SCCS and not lint */
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40
41 #include <sys/types.h>
42
43 #include <errno.h>
44 #include <stdio.h>
45 #include <string.h>
46
47 #include <db.h>
48 #include "recno.h"
49
50 static int rec_rdelete(BTREE *, recno_t);
51
52 /*
53 * __REC_DELETE -- Delete the item(s) referenced by a key.
54 *
55 * Parameters:
56 * dbp: pointer to access method
57 * key: key to delete
58 * flags: R_CURSOR if deleting what the cursor references
59 *
60 * Returns:
61 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
62 */
63 int
__rec_delete(const DB * dbp,const DBT * key,u_int flags)64 __rec_delete(const DB *dbp, const DBT *key, u_int flags)
65 {
66 BTREE *t;
67 recno_t nrec;
68 int status;
69
70 t = dbp->internal;
71
72 /* Toss any page pinned across calls. */
73 if (t->bt_pinned != NULL) {
74 mpool_put(t->bt_mp, t->bt_pinned, 0);
75 t->bt_pinned = NULL;
76 }
77
78 switch(flags) {
79 case 0:
80 if ((nrec = *(recno_t *)key->data) == 0)
81 goto einval;
82 if (nrec > t->bt_nrecs)
83 return (RET_SPECIAL);
84 --nrec;
85 status = rec_rdelete(t, nrec);
86 break;
87 case R_CURSOR:
88 if (!F_ISSET(&t->bt_cursor, CURS_INIT))
89 goto einval;
90 if (t->bt_nrecs == 0)
91 return (RET_SPECIAL);
92 status = rec_rdelete(t, t->bt_cursor.rcursor - 1);
93 if (status == RET_SUCCESS)
94 --t->bt_cursor.rcursor;
95 break;
96 default:
97 einval: errno = EINVAL;
98 return (RET_ERROR);
99 }
100
101 if (status == RET_SUCCESS)
102 F_SET(t, B_MODIFIED | R_MODIFIED);
103 return (status);
104 }
105
106 /*
107 * REC_RDELETE -- Delete the data matching the specified key.
108 *
109 * Parameters:
110 * tree: tree
111 * nrec: record to delete
112 *
113 * Returns:
114 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
115 */
116 static int
rec_rdelete(BTREE * t,recno_t nrec)117 rec_rdelete(BTREE *t, recno_t nrec)
118 {
119 EPG *e;
120 PAGE *h;
121 int status;
122
123 /* Find the record; __rec_search pins the page. */
124 if ((e = __rec_search(t, nrec, SDELETE)) == NULL)
125 return (RET_ERROR);
126
127 /* Delete the record. */
128 h = e->page;
129 status = __rec_dleaf(t, h, e->index);
130 if (status != RET_SUCCESS) {
131 mpool_put(t->bt_mp, h, 0);
132 return (status);
133 }
134 mpool_put(t->bt_mp, h, MPOOL_DIRTY);
135 return (RET_SUCCESS);
136 }
137
138 /*
139 * __REC_DLEAF -- Delete a single record from a recno leaf page.
140 *
141 * Parameters:
142 * t: tree
143 * idx: index on current page to delete
144 *
145 * Returns:
146 * RET_SUCCESS, RET_ERROR.
147 */
148 int
__rec_dleaf(BTREE * t,PAGE * h,u_int32_t idx)149 __rec_dleaf(BTREE *t, PAGE *h, u_int32_t idx)
150 {
151 RLEAF *rl;
152 indx_t *ip, cnt, offset;
153 u_int32_t nbytes;
154 char *from;
155 void *to;
156
157 /*
158 * Delete a record from a recno leaf page. Internal records are never
159 * deleted from internal pages, regardless of the records that caused
160 * them to be added being deleted. Pages made empty by deletion are
161 * not reclaimed. They are, however, made available for reuse.
162 *
163 * Pack the remaining entries at the end of the page, shift the indices
164 * down, overwriting the deleted record and its index. If the record
165 * uses overflow pages, make them available for reuse.
166 */
167 to = rl = GETRLEAF(h, idx);
168 if (rl->flags & P_BIGDATA && __ovfl_delete(t, rl->bytes) == RET_ERROR)
169 return (RET_ERROR);
170 nbytes = NRLEAF(rl);
171
172 /*
173 * Compress the key/data pairs. Compress and adjust the [BR]LEAF
174 * offsets. Reset the headers.
175 */
176 from = (char *)h + h->upper;
177 memmove(from + nbytes, from, (char *)to - from);
178 h->upper += nbytes;
179
180 offset = h->linp[idx];
181 for (cnt = &h->linp[idx] - (ip = &h->linp[0]); cnt--; ++ip)
182 if (ip[0] < offset)
183 ip[0] += nbytes;
184 for (cnt = &h->linp[NEXTINDEX(h)] - ip; --cnt; ++ip)
185 ip[0] = ip[1] < offset ? ip[1] + nbytes : ip[1];
186 h->lower -= sizeof(indx_t);
187 --t->bt_nrecs;
188 return (RET_SUCCESS);
189 }
190