Full_Name: Max Bolingbroke
Version: LMDB HEAD
OS: OS X
URL: ftp://ftp.openldap.org/incoming/max-bolingbroke-140730.patch
Submission from: (NULL) (81.111.197.81)
1. When using mdb_cursor_get(MDB_FIRST_DUP) or mdb_cursor_get(MDB_LAST_DUP) on a
cursor that is currently positioned on a key without any duplicate values, then
we should return MDB_NOTFOUND rather than EINVAL.
2. When using mdb_cursor_get(MDB_NEXT_DUP) on a cursor that is currently
positioned on the final key in the database, we should not return MDB_NOTFOUND
unless the value we are on is actually the final one within that key.
In particular I claim that the following C program should run to completion
without any errors. It does not, but the attached patch
(max-bolingbroke-140730.patch) makes it do so.
I, Maximilian Bolingbroke, hereby place the attached modifications to liblmdb
(and only these modifications) into the public domain. Hence, these
modifications may be freely used and/or redistributed for any purpose with or
without attribution and/or other notice.
#define _XOPEN_SOURCE 500
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdarg.h>
#include "lmdb.h"
void panic(const char * restrict format, ...) {
va_list argp;
va_start(argp, format);
vprintf(format, argp);
va_end(argp);
exit(1);
}
void mdb_check(char *context, int rc) {
if (rc != 0) {
panic("%s: %s", context, mdb_strerror(rc));
}
}
void mdb_check_notfound(char *context, int rc) {
if (rc != MDB_NOTFOUND) {
panic("%s: %s", context, mdb_strerror(rc));
}
}
int main(int argc, char **argv) {
srand(1337);
MDB_env *env;
mdb_check("mdb_env_create", mdb_env_create(&env));
mdb_check("mdb_env_set_maxdbs", mdb_env_set_maxdbs(env, 1));
mdb_check("mdb_env_set_mapsize", mdb_env_set_mapsize(env, 1024 * 1024));
mdb_check("mdb_env_open", mdb_env_open(env, "testdb", MDB_NOSUBDIR,
0644));
MDB_txn *txn;
mdb_check("mdb_txn_begin", mdb_txn_begin(env, NULL, 0, &txn));
MDB_dbi dbi;
mdb_check("mdb_dbi_open", mdb_dbi_open(txn, "root", MDB_CREATE |
MDB_DUPSORT,
&dbi));
int key;
int value;
MDB_val keyBuffer;
keyBuffer.mv_size = sizeof(int);
keyBuffer.mv_data = &key;
MDB_val valueBuffer;
valueBuffer.mv_size = sizeof(int);
valueBuffer.mv_data = &value;
{
key = 1; value = 100;
mdb_check("mdb_put", mdb_put(txn, dbi, &keyBuffer,
&valueBuffer, 0));
key = 2; value = 200;
mdb_check("mdb_put", mdb_put(txn, dbi, &keyBuffer,
&valueBuffer, 0));
key = 2; value = 201;
mdb_check("mdb_put", mdb_put(txn, dbi, &keyBuffer,
&valueBuffer, 0));
//AAA:key = 3; value = 300;
//AAA:mdb_check("mdb_put", mdb_put(txn, dbi, &keyBuffer,
&valueBuffer, 0));
}
{
MDB_cursor *cursor;
mdb_check("mdb_cursor_open", mdb_cursor_open(txn, dbi,
&cursor));
// BUG 1
// =====
// The MDB_FIRST_DUP/MDB_LAST_DUP moves fail (they should leave
the cursor
unchanged and return 0)
// This seems to happen because the key "1" only has a single
item and
mdb.c:5836 does not handle that properly.
mdb_check("mdb_cursor_get", mdb_cursor_get(cursor, &keyBuffer,
&valueBuffer,
MDB_FIRST));
mdb_check_notfound("mdb_cursor_get(MDB_NEXT_DUP)",
mdb_cursor_get(cursor,
&keyBuffer, &valueBuffer, MDB_NEXT_DUP));
mdb_check_notfound("mdb_cursor_get(MDB_PREV_DUP)",
mdb_cursor_get(cursor,
&keyBuffer, &valueBuffer, MDB_PREV_DUP));
mdb_check_notfound("mdb_cursor_get(MDB_FIRST_DUP)",
mdb_cursor_get(cursor,
&keyBuffer, &valueBuffer, MDB_FIRST_DUP));
mdb_check_notfound("mdb_cursor_get(MDB_LAST_DUP)",
mdb_cursor_get(cursor,
&keyBuffer, &valueBuffer, MDB_LAST_DUP));
// BUG 2
// =====
// This fails in a slightly different way because the key "2"
has multiple
items. Specifically, the MDB_NEXT_DUP call
// fails. If you uncomment all lines beginning with "//AAA:" to
add the key
"3" to the database
// (i.e. add it just after the key we are cursoring around in
here), then it
works as I expect. I think
// the problem is that the test for EOF at mdb.c:5267 is
bailing us out, when
it should
// instead be checking whether the subcursor has any items.
mdb_check("mdb_cursor_get", mdb_cursor_get(cursor, &keyBuffer,
&valueBuffer,
MDB_LAST));
//AAA:mdb_check("mdb_cursor_get", mdb_cursor_get(cursor,
&keyBuffer,
&valueBuffer, MDB_PREV));
mdb_check("mdb_cursor_get(MDB_PREV_DUP)",
mdb_cursor_get(cursor, &keyBuffer,
&valueBuffer, MDB_PREV_DUP));
mdb_check("mdb_cursor_get(MDB_NEXT_DUP)",
mdb_cursor_get(cursor, &keyBuffer,
&valueBuffer, MDB_NEXT_DUP));
mdb_check("mdb_cursor_get(MDB_FIRST_DUP)",
mdb_cursor_get(cursor, &keyBuffer,
&valueBuffer, MDB_FIRST_DUP));
mdb_check("mdb_cursor_get(MDB_LAST_DUP)",
mdb_cursor_get(cursor, &keyBuffer,
&valueBuffer, MDB_LAST_DUP));
mdb_cursor_close(cursor);
}
mdb_check("mdb_txn_commit", mdb_txn_commit(txn));
return 0;
}
