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. 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 * @(#)rec_delete.c 8.7 (Berkeley) 7/14/94
33 * $FreeBSD: head/lib/libc/db/recno/rec_delete.c 189292 2009-03-03 02:16:12Z delphij $
34 */
35
36 #include <sys/param.h>
37
38 #include <errno.h>
39 #include <stdio.h>
40 #include <string.h>
41
42 #include <db.h>
43 #include "recno.h"
44
45 static int rec_rdelete(BTREE *, recno_t);
46
47 /*
48 * __REC_DELETE -- Delete the item(s) referenced by a key.
49 *
50 * Parameters:
51 * dbp: pointer to access method
52 * key: key to delete
53 * flags: R_CURSOR if deleting what the cursor references
54 *
55 * Returns:
56 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
57 */
58 int
__rec_delete(const DB * dbp,const DBT * key,unsigned int flags)59 __rec_delete(const DB *dbp, const DBT *key, unsigned int flags)
60 {
61 BTREE *t;
62 recno_t nrec;
63 int status;
64
65 t = dbp->internal;
66
67 /* Toss any page pinned across calls. */
68 if (t->bt_pinned != NULL) {
69 mpool_put(t->bt_mp, t->bt_pinned, 0);
70 t->bt_pinned = NULL;
71 }
72
73 switch(flags) {
74 case 0:
75 if ((nrec = *(recno_t *)key->data) == 0)
76 goto einval;
77 if (nrec > t->bt_nrecs)
78 return (RET_SPECIAL);
79 --nrec;
80 status = rec_rdelete(t, nrec);
81 break;
82 case R_CURSOR:
83 if (!F_ISSET(&t->bt_cursor, CURS_INIT))
84 goto einval;
85 if (t->bt_nrecs == 0)
86 return (RET_SPECIAL);
87 status = rec_rdelete(t, t->bt_cursor.rcursor - 1);
88 if (status == RET_SUCCESS)
89 --t->bt_cursor.rcursor;
90 break;
91 default:
92 einval: errno = EINVAL;
93 return (RET_ERROR);
94 }
95
96 if (status == RET_SUCCESS)
97 F_SET(t, B_MODIFIED | R_MODIFIED);
98 return (status);
99 }
100
101 /*
102 * REC_RDELETE -- Delete the data matching the specified key.
103 *
104 * Parameters:
105 * tree: tree
106 * nrec: record to delete
107 *
108 * Returns:
109 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
110 */
111 static int
rec_rdelete(BTREE * t,recno_t nrec)112 rec_rdelete(BTREE *t, recno_t nrec)
113 {
114 EPG *e;
115 PAGE *h;
116 int status;
117
118 /* Find the record; __rec_search pins the page. */
119 if ((e = __rec_search(t, nrec, SDELETE)) == NULL)
120 return (RET_ERROR);
121
122 /* Delete the record. */
123 h = e->page;
124 status = __rec_dleaf(t, h, e->index);
125 if (status != RET_SUCCESS) {
126 mpool_put(t->bt_mp, h, 0);
127 return (status);
128 }
129 mpool_put(t->bt_mp, h, MPOOL_DIRTY);
130 return (RET_SUCCESS);
131 }
132
133 /*
134 * __REC_DLEAF -- Delete a single record from a recno leaf page.
135 *
136 * Parameters:
137 * t: tree
138 * idx: index on current page to delete
139 *
140 * Returns:
141 * RET_SUCCESS, RET_ERROR.
142 */
143 int
__rec_dleaf(BTREE * t,PAGE * h,uint32_t idx)144 __rec_dleaf(BTREE *t, PAGE *h, uint32_t idx)
145 {
146 RLEAF *rl;
147 indx_t *ip, cnt, offset;
148 uint32_t nbytes;
149 char *from;
150 void *to;
151
152 /*
153 * Delete a record from a recno leaf page. Internal records are never
154 * deleted from internal pages, regardless of the records that caused
155 * them to be added being deleted. Pages made empty by deletion are
156 * not reclaimed. They are, however, made available for reuse.
157 *
158 * Pack the remaining entries at the end of the page, shift the indices
159 * down, overwriting the deleted record and its index. If the record
160 * uses overflow pages, make them available for reuse.
161 */
162 to = rl = GETRLEAF(h, idx);
163 if (rl->flags & P_BIGDATA && __ovfl_delete(t, rl->bytes) == RET_ERROR)
164 return (RET_ERROR);
165 nbytes = NRLEAF(rl);
166
167 /*
168 * Compress the key/data pairs. Compress and adjust the [BR]LEAF
169 * offsets. Reset the headers.
170 */
171 from = (char *)h + h->upper;
172 memmove(from + nbytes, from, (char *)to - from);
173 h->upper += nbytes;
174
175 offset = h->linp[idx];
176 for (cnt = &h->linp[idx] - (ip = &h->linp[0]); cnt--; ++ip)
177 if (ip[0] < offset)
178 ip[0] += nbytes;
179 for (cnt = &h->linp[NEXTINDEX(h)] - ip; --cnt; ++ip)
180 ip[0] = ip[1] < offset ? ip[1] + nbytes : ip[1];
181 h->lower -= sizeof(indx_t);
182 --t->bt_nrecs;
183 return (RET_SUCCESS);
184 }
185