| bt_get.c (1573) | bt_get.c (14272) |
|---|---|
| 1/*- | 1/*- |
| 2 * Copyright (c) 1990, 1993 | 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: --- 19 unchanged lines hidden (view full) --- 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) | 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: --- 19 unchanged lines hidden (view full) --- 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) |
| 38static char sccsid[] = "@(#)bt_get.c 8.2 (Berkeley) 9/7/93"; | 38static char sccsid[] = "@(#)bt_get.c 8.6 (Berkeley) 7/20/94"; |
| 39#endif /* LIBC_SCCS and not lint */ 40 41#include <sys/types.h> 42 43#include <errno.h> 44#include <stddef.h> 45#include <stdio.h> 46 --- 39 unchanged lines hidden (view full) --- 86 87 if ((e = __bt_search(t, key, &exact)) == NULL) 88 return (RET_ERROR); 89 if (!exact) { 90 mpool_put(t->bt_mp, e->page, 0); 91 return (RET_SPECIAL); 92 } 93 | 39#endif /* LIBC_SCCS and not lint */ 40 41#include <sys/types.h> 42 43#include <errno.h> 44#include <stddef.h> 45#include <stdio.h> 46 --- 39 unchanged lines hidden (view full) --- 86 87 if ((e = __bt_search(t, key, &exact)) == NULL) 88 return (RET_ERROR); 89 if (!exact) { 90 mpool_put(t->bt_mp, e->page, 0); 91 return (RET_SPECIAL); 92 } 93 |
| 94 /* 95 * A special case is if we found the record but it's flagged for 96 * deletion. In this case, we want to find another record with the 97 * same key, if it exists. Rather than look around the tree we call 98 * __bt_first and have it redo the search, as __bt_first will not 99 * return keys marked for deletion. Slow, but should never happen. 100 */ 101 if (ISSET(t, B_DELCRSR) && e->page->pgno == t->bt_bcursor.pgno && 102 e->index == t->bt_bcursor.index) { 103 mpool_put(t->bt_mp, e->page, 0); 104 if ((e = __bt_first(t, key, &exact)) == NULL) 105 return (RET_ERROR); 106 if (!exact) 107 return (RET_SPECIAL); 108 } | 94 status = __bt_ret(t, e, NULL, NULL, data, &t->bt_rdata, 0); |
| 109 | 95 |
| 110 status = __bt_ret(t, e, NULL, data); | |
| 111 /* 112 * If the user is doing concurrent access, we copied the 113 * key/data, toss the page. 114 */ | 96 /* 97 * If the user is doing concurrent access, we copied the 98 * key/data, toss the page. 99 */ |
| 115 if (ISSET(t, B_DB_LOCK)) | 100 if (F_ISSET(t, B_DB_LOCK)) |
| 116 mpool_put(t->bt_mp, e->page, 0); 117 else 118 t->bt_pinned = e->page; 119 return (status); 120} | 101 mpool_put(t->bt_mp, e->page, 0); 102 else 103 t->bt_pinned = e->page; 104 return (status); 105} |
| 121 122/* 123 * __BT_FIRST -- Find the first entry. 124 * 125 * Parameters: 126 * t: the tree 127 * key: the key 128 * 129 * Returns: 130 * The first entry in the tree greater than or equal to key. 131 */ 132EPG * 133__bt_first(t, key, exactp) 134 BTREE *t; 135 const DBT *key; 136 int *exactp; 137{ 138 register PAGE *h; 139 register EPG *e; 140 EPG save; 141 pgno_t cpgno, pg; 142 indx_t cindex; 143 int found; 144 145 /* 146 * Find any matching record; __bt_search pins the page. Only exact 147 * matches are tricky, otherwise just return the location of the key 148 * if it were to be inserted into the tree. 149 */ 150 if ((e = __bt_search(t, key, exactp)) == NULL) 151 return (NULL); 152 if (!*exactp) 153 return (e); 154 155 if (ISSET(t, B_DELCRSR)) { 156 cpgno = t->bt_bcursor.pgno; 157 cindex = t->bt_bcursor.index; 158 } else { 159 cpgno = P_INVALID; 160 cindex = 0; /* GCC thinks it's uninitialized. */ 161 } 162 163 /* 164 * Walk backwards, skipping empty pages, as long as the entry matches 165 * and there are keys left in the tree. Save a copy of each match in 166 * case we go too far. A special case is that we don't return a match 167 * on records that the cursor references that have already been flagged 168 * for deletion. 169 */ 170 save = *e; 171 h = e->page; 172 found = 0; 173 do { 174 if (cpgno != h->pgno || cindex != e->index) { 175 if (save.page->pgno != e->page->pgno) { 176 mpool_put(t->bt_mp, save.page, 0); 177 save = *e; 178 } else 179 save.index = e->index; 180 found = 1; 181 } 182 /* 183 * Make a special effort not to unpin the page the last (or 184 * original) match was on, but also make sure it's unpinned 185 * if an error occurs. 186 */ 187 while (e->index == 0) { 188 if (h->prevpg == P_INVALID) 189 goto done1; 190 if (h->pgno != save.page->pgno) 191 mpool_put(t->bt_mp, h, 0); 192 if ((h = mpool_get(t->bt_mp, h->prevpg, 0)) == NULL) { 193 if (h->pgno == save.page->pgno) 194 mpool_put(t->bt_mp, save.page, 0); 195 return (NULL); 196 } 197 e->page = h; 198 e->index = NEXTINDEX(h); 199 } 200 --e->index; 201 } while (__bt_cmp(t, key, e) == 0); 202 203 /* 204 * Reach here with the last page that was looked at pinned, which may 205 * or may not be the same as the last (or original) match page. If 206 * it's not useful, release it. 207 */ 208done1: if (h->pgno != save.page->pgno) 209 mpool_put(t->bt_mp, h, 0); 210 211 /* 212 * If still haven't found a record, the only possibility left is the 213 * next one. Move forward one slot, skipping empty pages and check. 214 */ 215 if (!found) { 216 h = save.page; 217 if (++save.index == NEXTINDEX(h)) { 218 do { 219 pg = h->nextpg; 220 mpool_put(t->bt_mp, h, 0); 221 if (pg == P_INVALID) { 222 *exactp = 0; 223 return (e); 224 } 225 if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL) 226 return (NULL); 227 } while ((save.index = NEXTINDEX(h)) == 0); 228 save.page = h; 229 } 230 if (__bt_cmp(t, key, &save) != 0) { 231 *exactp = 0; 232 return (e); 233 } 234 } 235 *e = save; 236 *exactp = 1; 237 return (e); 238} | |