/* ----------------
* index_rescan - (re)start a scan of an index
*
* During a restart, the caller may specify a new set of scankeys and/or
* orderbykeys; but the number of keys cannot differ from what index_beginscan
* was told. (Later we might relax that to "must not exceed", but currently
* the index AMs tend to assume that scan->numberOfKeys is what to believe.)
* To restart the scan without changing keys, pass NULL for the key arrays.
* (Of course, keys *must* be passed on the first call, unless
* scan->numberOfKeys is zero.)
* ----------------
*/
void
index_rescan(IndexScanDesc scan,
ScanKey keys, int nkeys,
ScanKey orderbys, int norderbys)
{
FmgrInfo *procedure;
SCAN_CHECKS;
GET_SCAN_PROCEDURE(amrescan);
Assert(nkeys == scan->numberOfKeys);
Assert(norderbys == scan->numberOfOrderBys);
/* Release any held pin on a heap page */
if (BufferIsValid(scan->xs_cbuf))
{
ReleaseBuffer(scan->xs_cbuf);
scan->xs_cbuf = InvalidBuffer;
}
scan->xs_continue_hot = false;
scan->kill_prior_tuple = false; /* for safety */
FunctionCall5(procedure,
PointerGetDatum(scan),
PointerGetDatum(keys),
Int32GetDatum(nkeys),
PointerGetDatum(orderbys),
Int32GetDatum(norderbys));
}
/*
* Perform default encoding conversion using cached FmgrInfo. Since
* this function does not access database at all, it is safe to call
* outside transactions. Explicit setting client encoding required
* before calling this function. Otherwise no conversion is
* performed.
*/
static unsigned char *
perform_default_encoding_conversion(unsigned char *src, int len, bool is_client_to_server)
{
unsigned char *result;
int src_encoding,
dest_encoding;
FmgrInfo *flinfo;
if (is_client_to_server)
{
src_encoding = ClientEncoding->encoding;
dest_encoding = DatabaseEncoding->encoding;
flinfo = ToServerConvProc;
}
else
{
src_encoding = DatabaseEncoding->encoding;
dest_encoding = ClientEncoding->encoding;
flinfo = ToClientConvProc;
}
if (flinfo == NULL)
return src;
result = palloc(len * 4 + 1);
FunctionCall5(flinfo,
Int32GetDatum(src_encoding),
Int32GetDatum(dest_encoding),
CStringGetDatum(src),
CStringGetDatum(result),
Int32GetDatum(len));
return result;
}
/*
* Perform default encoding conversion using cached FmgrInfo. Since
* this function does not access database at all, it is safe to call
* outside transactions. Explicit setting client encoding required
* before calling this function. Otherwise no conversion is
* performed.
*
* NOTE: this function was slightly updated to allow passing in a source
* encoding that is not necessarily ClientEncoding->encoding for client-to-
* server conversion. Default value is -1, which means: use ClientEncoding.
* See pg_custom_client_to_server for information.
*/
static char *
perform_default_encoding_conversion(const char *src, int len, bool is_client_to_server,
int custom_client_encoding,
FmgrInfo *custom_encoding_proc)
{
char *result;
int src_encoding,
dest_encoding;
FmgrInfo *flinfo;
if (is_client_to_server)
{
if(custom_client_encoding == -1)
{
/* this is the normal path of execution */
src_encoding = ClientEncoding->encoding;
dest_encoding = DatabaseEncoding->encoding;
flinfo = ToServerConvProc;
}
else
{
/* this is the custom path of execution, for external tbl encodings */
src_encoding = custom_client_encoding;
dest_encoding = DatabaseEncoding->encoding;
flinfo = custom_encoding_proc;
}
}
else
{
if(custom_client_encoding == -1)
{
/* this is the normal path of execution */
src_encoding = DatabaseEncoding->encoding;
dest_encoding = ClientEncoding->encoding;
flinfo = ToClientConvProc;
}
else
{
/* this is the custom path of execution, for external tbl encodings */
src_encoding = DatabaseEncoding->encoding;
dest_encoding = custom_client_encoding;
flinfo = custom_encoding_proc;
}
}
if (flinfo == NULL)
return (char *) src;
/*
* Allocate space for conversion result, being wary of integer overflow
*/
if ((Size) len >= (MaxAllocSize / (Size) MAX_CONVERSION_GROWTH))
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("out of memory"),
errdetail("String of %d bytes is too long for encoding conversion.",
len)));
result = palloc(len * MAX_CONVERSION_GROWTH + 1);
FunctionCall5(flinfo,
Int32GetDatum(src_encoding),
Int32GetDatum(dest_encoding),
CStringGetDatum((char *) src),
CStringGetDatum(result),
Int32GetDatum(len));
return result;
}
