/*
* __curindex_search_near --
* WT_CURSOR->search_near method for index cursors.
*/
static int
__curindex_search_near(WT_CURSOR *cursor, int *exact)
{
WT_CURSOR *child;
WT_CURSOR_INDEX *cindex;
WT_DECL_RET;
WT_ITEM found_key;
WT_SESSION_IMPL *session;
int cmp;
cindex = (WT_CURSOR_INDEX *)cursor;
child = cindex->child;
JOINABLE_CURSOR_API_CALL(cursor, session, search, NULL);
/*
* We are searching using the application-specified key, which
* (usually) doesn't contain the primary key, so it is just a prefix of
* any matching index key. That said, if there is an exact match, we
* want to find the first matching index entry and set exact equal to
* zero.
*
* Do a search_near, and if we find an entry that is too small, step to
* the next one. In the unlikely event of a search past the end of the
* tree, go back to the last key.
*/
__wt_cursor_set_raw_key(child, &cursor->key);
WT_ERR(child->search_near(child, &cmp));
if (cmp < 0) {
if ((ret = child->next(child)) == WT_NOTFOUND)
ret = child->prev(child);
WT_ERR(ret);
}
/*
* We expect partial matches, and want the smallest record with a key
* greater than or equal to the search key.
*
* If the found key starts with the search key, we indicate a match by
* setting exact equal to zero.
*
* The compare function expects application-supplied keys to come first
* so we flip the sign of the result to match what callers expect.
*/
found_key = child->key;
if (found_key.size > cursor->key.size)
found_key.size = cursor->key.size;
WT_ERR(__wt_compare(
session, cindex->index->collator, &cursor->key, &found_key, exact));
*exact = -*exact;
WT_ERR(__curindex_move(cindex));
if (0) {
err: F_CLR(cursor, WT_CURSTD_KEY_INT | WT_CURSTD_VALUE_INT);
}
API_END_RET(session, ret);
}
/*
* __curindex_search --
* WT_CURSOR->search method for index cursors.
*/
static int
__curindex_search(WT_CURSOR *cursor)
{
WT_CURSOR *child;
WT_CURSOR_INDEX *cindex;
WT_DECL_RET;
WT_ITEM found_key;
WT_SESSION_IMPL *session;
int cmp;
cindex = (WT_CURSOR_INDEX *)cursor;
child = cindex->child;
JOINABLE_CURSOR_API_CALL(cursor, session, search, NULL);
/*
* We are searching using the application-specified key, which
* (usually) doesn't contain the primary key, so it is just a prefix of
* any matching index key. Do a search_near, step to the next entry if
* we land on one that is too small, then check that the prefix
* matches.
*/
__wt_cursor_set_raw_key(child, &cursor->key);
WT_ERR(child->search_near(child, &cmp));
if (cmp < 0)
WT_ERR(child->next(child));
/*
* We expect partial matches, and want the smallest record with a key
* greater than or equal to the search key.
*
* If the key we find is shorter than the search key, it can't possibly
* match.
*
* The only way for the key to be exactly equal is if there is an index
* on the primary key, because otherwise the primary key columns will
* be appended to the index key, but we don't disallow that (odd) case.
*/
found_key = child->key;
if (found_key.size < cursor->key.size)
WT_ERR(WT_NOTFOUND);
found_key.size = cursor->key.size;
WT_ERR(__wt_compare(
session, cindex->index->collator, &cursor->key, &found_key, &cmp));
if (cmp != 0) {
ret = WT_NOTFOUND;
goto err;
}
WT_ERR(__curindex_move(cindex));
if (0) {
err: F_CLR(cursor, WT_CURSTD_KEY_INT | WT_CURSTD_VALUE_INT);
}
API_END_RET(session, ret);
}
/*
* __curindex_prev --
* WT_CURSOR->prev method for index cursors.
*/
static int
__curindex_prev(WT_CURSOR *cursor)
{
WT_CURSOR_INDEX *cindex;
WT_DECL_RET;
WT_SESSION_IMPL *session;
cindex = (WT_CURSOR_INDEX *)cursor;
JOINABLE_CURSOR_API_CALL(cursor, session, prev, NULL);
F_CLR(cursor, WT_CURSTD_KEY_SET | WT_CURSTD_VALUE_SET);
if ((ret = cindex->child->prev(cindex->child)) == 0)
ret = __curindex_move(cindex);
err: API_END_RET(session, ret);
}
/*
* __curindex_search_near --
* WT_CURSOR->search_near method for index cursors.
*/
static int
__curindex_search_near(WT_CURSOR *cursor, int *exact)
{
WT_CURSOR_INDEX *cindex;
WT_DECL_RET;
WT_SESSION_IMPL *session;
cindex = (WT_CURSOR_INDEX *)cursor;
JOINABLE_CURSOR_API_CALL(cursor, session, search_near, NULL);
__wt_cursor_set_raw_key(cindex->child, &cursor->key);
if ((ret = cindex->child->search_near(cindex->child, exact)) == 0)
ret = __curindex_move(cindex);
else
F_CLR(cursor, WT_CURSTD_KEY_INT | WT_CURSTD_VALUE_INT);
err: API_END_RET(session, ret);
}
