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/*
* contrib/hstore/hstore_gin.c
*/
#include "postgres.h"
#include "access/gin.h"
#include "access/stratnum.h"
#include "catalog/pg_type.h"
#include "hstore.h"
/*
* When using a GIN index for hstore, we choose to index both keys and values.
* The storage format is "text" values, with K, V, or N prepended to the string
* to indicate key, value, or null values. (As of 9.1 it might be better to
* store null values as nulls, but we'll keep it this way for on-disk
* compatibility.)
*/
#define KEYFLAG 'K'
#define VALFLAG 'V'
#define NULLFLAG 'N'
PG_FUNCTION_INFO_V1(gin_extract_hstore);
/* Build an indexable text value */
static text *
makeitem(char *str, int len, char flag)
{
text *item;
item = (text *) palloc(VARHDRSZ + len + 1);
SET_VARSIZE(item, VARHDRSZ + len + 1);
*VARDATA(item) = flag;
if (str && len > 0)
memcpy(VARDATA(item) + 1, str, len);
return item;
}
Datum
gin_extract_hstore(PG_FUNCTION_ARGS)
{
HStore *hs = PG_GETARG_HSTORE_P(0);
int32 *nentries = (int32 *) PG_GETARG_POINTER(1);
Datum *entries = NULL;
HEntry *hsent = ARRPTR(hs);
char *ptr = STRPTR(hs);
int count = HS_COUNT(hs);
int i;
*nentries = 2 * count;
if (count)
entries = (Datum *) palloc(sizeof(Datum) * 2 * count);
for (i = 0; i < count; ++i)
{
text *item;
item = makeitem(HSTORE_KEY(hsent, ptr, i),
HSTORE_KEYLEN(hsent, i),
KEYFLAG);
entries[2 * i] = PointerGetDatum(item);
if (HSTORE_VALISNULL(hsent, i))
item = makeitem(NULL, 0, NULLFLAG);
else
item = makeitem(HSTORE_VAL(hsent, ptr, i),
HSTORE_VALLEN(hsent, i),
VALFLAG);
entries[2 * i + 1] = PointerGetDatum(item);
}
PG_RETURN_POINTER(entries);
}
PG_FUNCTION_INFO_V1(gin_extract_hstore_query);
Datum
gin_extract_hstore_query(PG_FUNCTION_ARGS)
{
int32 *nentries = (int32 *) PG_GETARG_POINTER(1);
StrategyNumber strategy = PG_GETARG_UINT16(2);
int32 *searchMode = (int32 *) PG_GETARG_POINTER(6);
Datum *entries;
if (strategy == HStoreContainsStrategyNumber)
{
/* Query is an hstore, so just apply gin_extract_hstore... */
entries = (Datum *)
DatumGetPointer(DirectFunctionCall2(gin_extract_hstore,
PG_GETARG_DATUM(0),
PointerGetDatum(nentries)));
/* ... except that "contains {}" requires a full index scan */
if (entries == NULL)
*searchMode = GIN_SEARCH_MODE_ALL;
}
else if (strategy == HStoreExistsStrategyNumber)
{
text *query = PG_GETARG_TEXT_PP(0);
text *item;
*nentries = 1;
entries = (Datum *) palloc(sizeof(Datum));
item = makeitem(VARDATA_ANY(query), VARSIZE_ANY_EXHDR(query), KEYFLAG);
entries[0] = PointerGetDatum(item);
}
else if (strategy == HStoreExistsAnyStrategyNumber ||
strategy == HStoreExistsAllStrategyNumber)
{
ArrayType *query = PG_GETARG_ARRAYTYPE_P(0);
Datum *key_datums;
bool *key_nulls;
int key_count;
int i,
j;
text *item;
deconstruct_array(query,
TEXTOID, -1, false, TYPALIGN_INT,
&key_datums, &key_nulls, &key_count);
entries = (Datum *) palloc(sizeof(Datum) * key_count);
for (i = 0, j = 0; i < key_count; ++i)
{
/* Nulls in the array are ignored, cf hstoreArrayToPairs */
if (key_nulls[i])
continue;
item = makeitem(VARDATA(key_datums[i]), VARSIZE(key_datums[i]) - VARHDRSZ, KEYFLAG);
entries[j++] = PointerGetDatum(item);
}
*nentries = j;
/* ExistsAll with no keys should match everything */
if (j == 0 && strategy == HStoreExistsAllStrategyNumber)
*searchMode = GIN_SEARCH_MODE_ALL;
}
else
{
elog(ERROR, "unrecognized strategy number: %d", strategy);
entries = NULL; /* keep compiler quiet */
}
PG_RETURN_POINTER(entries);
}
PG_FUNCTION_INFO_V1(gin_consistent_hstore);
Datum
gin_consistent_hstore(PG_FUNCTION_ARGS)
{
bool *check = (bool *) PG_GETARG_POINTER(0);
StrategyNumber strategy = PG_GETARG_UINT16(1);
/* HStore *query = PG_GETARG_HSTORE_P(2); */
int32 nkeys = PG_GETARG_INT32(3);
/* Pointer *extra_data = (Pointer *) PG_GETARG_POINTER(4); */
bool *recheck = (bool *) PG_GETARG_POINTER(5);
bool res = true;
int32 i;
if (strategy == HStoreContainsStrategyNumber)
{
/*
* Index doesn't have information about correspondence of keys and
* values, so we need recheck. However, if not all the keys are
* present, we can fail at once.
*/
*recheck = true;
for (i = 0; i < nkeys; i++)
{
if (!check[i])
{
res = false;
break;
}
}
}
else if (strategy == HStoreExistsStrategyNumber)
{
/* Existence of key is guaranteed in default search mode */
*recheck = false;
res = true;
}
else if (strategy == HStoreExistsAnyStrategyNumber)
{
/* Existence of key is guaranteed in default search mode */
*recheck = false;
res = true;
}
else if (strategy == HStoreExistsAllStrategyNumber)
{
/* Testing for all the keys being present gives an exact result */
*recheck = false;
for (i = 0; i < nkeys; i++)
{
if (!check[i])
{
res = false;
break;
}
}
}
else
elog(ERROR, "unrecognized strategy number: %d", strategy);
PG_RETURN_BOOL(res);
}
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