1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
|
/*-
* Public Domain 2014-2016 MongoDB, Inc.
* Public Domain 2008-2014 WiredTiger, Inc.
*
* This is free and unencumbered software released into the public domain.
*
* Anyone is free to copy, modify, publish, use, compile, sell, or
* distribute this software, either in source code form or as a compiled
* binary, for any purpose, commercial or non-commercial, and by any
* means.
*
* In jurisdictions that recognize copyright laws, the author or authors
* of this software dedicate any and all copyright interest in the
* software to the public domain. We make this dedication for the benefit
* of the public at large and to the detriment of our heirs and
* successors. We intend this dedication to be an overt act of
* relinquishment in perpetuity of all present and future rights to this
* software under copyright law.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
* ex_scope.c
* demonstrates the scope of buffers holding cursor keys and values.
*/
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wiredtiger.h>
#ifdef _WIN32
/* snprintf is not supported on <= VS2013 */
#define snprintf _snprintf
#endif
static const char *home;
static int
cursor_scope_ops(WT_CURSOR *cursor)
{
struct {
const char *op;
const char *key;
const char *value;
int (*apply)(WT_CURSOR *);
} *op, ops[] = {
{ "insert", "key1", "value1", cursor->insert, },
{ "update", "key1", "value2", cursor->update, },
{ "search", "key1", "value2", cursor->search, },
{ "remove", "key1", "value2", cursor->remove, },
{ NULL, NULL, NULL, NULL }
};
WT_SESSION *session;
const char *key, *value;
char keybuf[10], valuebuf[10];
int ret;
session = cursor->session;
for (op = ops; op->key != NULL; op++) {
key = value = NULL;
/*! [cursor scope operation] */
(void)snprintf(keybuf, sizeof(keybuf), "%s", op->key);
cursor->set_key(cursor, keybuf);
(void)snprintf(valuebuf, sizeof(valuebuf), "%s", op->value);
cursor->set_value(cursor, valuebuf);
/*
* The application must keep key and value memory valid until
* the next operation that positions the cursor, modifies the
* data, or resets or closes the cursor.
*
* Modifying either the key or value buffers is not permitted.
*/
/* Apply the operation (insert, update, search or remove). */
if ((ret = op->apply(cursor)) != 0) {
fprintf(stderr,
"%s: error performing the operation: %s\n",
op->op, session->strerror(session, ret));
return (ret);
}
/*
* The cursor no longer references application memory, so
* application buffers can be safely overwritten.
*/
strcpy(keybuf, "no key");
strcpy(valuebuf, "no value");
/*
* Check that get_key/value behave as expected after the
* operation.
*/
if (op->apply == cursor->insert) {
/*
* WT_CURSOR::insert no longer references application
* memory, but as it does not position the cursor, it
* doesn't reference memory owned by the cursor, either.
*/
if ((ret = cursor->get_key(cursor, &key)) == 0 ||
(ret = cursor->get_value(cursor, &value)) == 0) {
fprintf(stderr,
"%s: error in s get_key/value: %s\n",
op->op, session->strerror(session, ret));
return (ret);
}
continue;
}
if (op->apply == cursor->remove) {
/*
* WT_CURSOR::remove no longer references application
* memory; as it does not position the cursor, it will
* reference key memory owned by the cursor, but has no
* value.
*/
if ((ret = cursor->get_key(cursor, &key)) != 0 ||
(ret = cursor->get_value(cursor, &value)) == 0) {
fprintf(stderr,
"%s: error in get_key/value: %s\n",
op->op, session->strerror(session, ret));
return (ret);
}
} else /* search, update */{
/*
* WT_CURSOR::search and WT_CURSOR::update no longer
* reference application memory; as they position the
* cursor, they will reference key/value memory owned
* by the cursor.
*/
if ((ret = cursor->get_key(cursor, &key)) != 0 ||
(ret = cursor->get_value(cursor, &value)) != 0) {
fprintf(stderr,
"%s: error in get_key/value: %s\n",
op->op, session->strerror(session, ret));
return (ret);
}
}
/*
* Modifying the memory referenced by either key or value is
* not permitted.
*
* Check that the cursor's key and value are what we expect.
*/
if (key == keybuf ||
(op->apply != cursor->remove && value == valuebuf)) {
fprintf(stderr,
"%s: cursor points at application memory!\n",
op->op);
return (EINVAL);
}
if (strcmp(key, op->key) != 0 ||
(op->apply != cursor->remove &&
strcmp(value, op->value) != 0)) {
fprintf(stderr,
"%s: unexpected key / value!\n", op->op);
return (EINVAL);
}
/*! [cursor scope operation] */
}
return (0);
}
int
main(void)
{
WT_CONNECTION *conn;
WT_CURSOR *cursor;
WT_SESSION *session;
int ret, tret;
/*
* Create a clean test directory for this run of the test program if the
* environment variable isn't already set (as is done by make check).
*/
if (getenv("WIREDTIGER_HOME") == NULL) {
home = "WT_HOME";
ret = system("rm -rf WT_HOME && mkdir WT_HOME");
} else
home = NULL;
/* Open a connection, create a simple table, open a cursor. */
if ((ret = wiredtiger_open(home, NULL, "create", &conn)) != 0 ||
(ret = conn->open_session(conn, NULL, NULL, &session)) != 0) {
fprintf(stderr, "Error connecting to %s: %s\n",
home, wiredtiger_strerror(ret));
return (ret);
}
ret = session->create(session,
"table:scope", "key_format=S,value_format=S,columns=(k,v)");
ret = session->open_cursor(session,
"table:scope", NULL, NULL, &cursor);
ret = cursor_scope_ops(cursor);
/* Close the connection and clean up. */
if ((tret = conn->close(conn, NULL)) != 0 && ret == 0)
ret = tret;
return (ret);
}
|
