/*
* EOH_init_header
*
* Initialize the common header of an expanded object.
*
* The main thing this encapsulates is initializing the TOAST pointers.
*/
void
EOH_init_header(ExpandedObjectHeader *eohptr,
const ExpandedObjectMethods *methods,
MemoryContext obj_context)
{
varatt_expanded ptr;
eohptr->vl_len_ = EOH_HEADER_MAGIC;
eohptr->eoh_methods = methods;
eohptr->eoh_context = obj_context;
ptr.eohptr = eohptr;
SET_VARTAG_EXTERNAL(eohptr->eoh_rw_ptr, VARTAG_EXPANDED_RW);
memcpy(VARDATA_EXTERNAL(eohptr->eoh_rw_ptr), &ptr, sizeof(ptr));
SET_VARTAG_EXTERNAL(eohptr->eoh_ro_ptr, VARTAG_EXPANDED_RO);
memcpy(VARDATA_EXTERNAL(eohptr->eoh_ro_ptr), &ptr, sizeof(ptr));
}
Datum
make_tuple_indirect(PG_FUNCTION_ARGS)
{
HeapTupleHeader rec = PG_GETARG_HEAPTUPLEHEADER(0);
HeapTupleData tuple;
int ncolumns;
Datum *values;
bool *nulls;
Oid tupType;
int32 tupTypmod;
TupleDesc tupdesc;
HeapTuple newtup;
int i;
MemoryContext old_context;
/* Extract type info from the tuple itself */
tupType = HeapTupleHeaderGetTypeId(rec);
tupTypmod = HeapTupleHeaderGetTypMod(rec);
tupdesc = lookup_rowtype_tupdesc(tupType, tupTypmod);
ncolumns = tupdesc->natts;
/* Build a temporary HeapTuple control structure */
tuple.t_len = HeapTupleHeaderGetDatumLength(rec);
ItemPointerSetInvalid(&(tuple.t_self));
tuple.t_tableOid = InvalidOid;
tuple.t_data = rec;
values = (Datum *) palloc(ncolumns * sizeof(Datum));
nulls = (bool *) palloc(ncolumns * sizeof(bool));
heap_deform_tuple(&tuple, tupdesc, values, nulls);
old_context = MemoryContextSwitchTo(TopTransactionContext);
for (i = 0; i < ncolumns; i++)
{
struct varlena *attr;
struct varlena *new_attr;
struct varatt_indirect redirect_pointer;
/* only work on existing, not-null varlenas */
if (TupleDescAttr(tupdesc, i)->attisdropped ||
nulls[i] ||
TupleDescAttr(tupdesc, i)->attlen != -1)
continue;
attr = (struct varlena *) DatumGetPointer(values[i]);
/* don't recursively indirect */
if (VARATT_IS_EXTERNAL_INDIRECT(attr))
continue;
/* copy datum, so it still lives later */
if (VARATT_IS_EXTERNAL_ONDISK(attr))
attr = heap_tuple_fetch_attr(attr);
else
{
struct varlena *oldattr = attr;
attr = palloc0(VARSIZE_ANY(oldattr));
memcpy(attr, oldattr, VARSIZE_ANY(oldattr));
}
/* build indirection Datum */
new_attr = (struct varlena *) palloc0(INDIRECT_POINTER_SIZE);
redirect_pointer.pointer = attr;
SET_VARTAG_EXTERNAL(new_attr, VARTAG_INDIRECT);
memcpy(VARDATA_EXTERNAL(new_attr), &redirect_pointer,
sizeof(redirect_pointer));
values[i] = PointerGetDatum(new_attr);
}
newtup = heap_form_tuple(tupdesc, values, nulls);
pfree(values);
pfree(nulls);
ReleaseTupleDesc(tupdesc);
MemoryContextSwitchTo(old_context);
/*
* We intentionally don't use PG_RETURN_HEAPTUPLEHEADER here, because that
* would cause the indirect toast pointers to be flattened out of the
* tuple immediately, rendering subsequent testing irrelevant. So just
* return the HeapTupleHeader pointer as-is. This violates the general
* rule that composite Datums shouldn't contain toast pointers, but so
* long as the regression test scripts don't insert the result of this
* function into a container type (record, array, etc) it should be OK.
*/
PG_RETURN_POINTER(newtup->t_data);
}
Datum
make_tuple_indirect(PG_FUNCTION_ARGS)
{
HeapTupleHeader rec = PG_GETARG_HEAPTUPLEHEADER(0);
HeapTupleData tuple;
int ncolumns;
Datum *values;
bool *nulls;
Oid tupType;
int32 tupTypmod;
TupleDesc tupdesc;
HeapTuple newtup;
int i;
MemoryContext old_context;
/* Extract type info from the tuple itself */
tupType = HeapTupleHeaderGetTypeId(rec);
tupTypmod = HeapTupleHeaderGetTypMod(rec);
tupdesc = lookup_rowtype_tupdesc(tupType, tupTypmod);
ncolumns = tupdesc->natts;
/* Build a temporary HeapTuple control structure */
tuple.t_len = HeapTupleHeaderGetDatumLength(rec);
ItemPointerSetInvalid(&(tuple.t_self));
tuple.t_tableOid = InvalidOid;
tuple.t_data = rec;
values = (Datum *) palloc(ncolumns * sizeof(Datum));
nulls = (bool *) palloc(ncolumns * sizeof(bool));
heap_deform_tuple(&tuple, tupdesc, values, nulls);
old_context = MemoryContextSwitchTo(TopTransactionContext);
for (i = 0; i < ncolumns; i++)
{
struct varlena *attr;
struct varlena *new_attr;
struct varatt_indirect redirect_pointer;
/* only work on existing, not-null varlenas */
if (tupdesc->attrs[i]->attisdropped ||
nulls[i] ||
tupdesc->attrs[i]->attlen != -1)
continue;
attr = (struct varlena *) DatumGetPointer(values[i]);
/* don't recursively indirect */
if (VARATT_IS_EXTERNAL_INDIRECT(attr))
continue;
/* copy datum, so it still lives later */
if (VARATT_IS_EXTERNAL_ONDISK(attr))
attr = heap_tuple_fetch_attr(attr);
else
{
struct varlena *oldattr = attr;
attr = palloc0(VARSIZE_ANY(oldattr));
memcpy(attr, oldattr, VARSIZE_ANY(oldattr));
}
/* build indirection Datum */
new_attr = (struct varlena *) palloc0(INDIRECT_POINTER_SIZE);
redirect_pointer.pointer = attr;
SET_VARTAG_EXTERNAL(new_attr, VARTAG_INDIRECT);
memcpy(VARDATA_EXTERNAL(new_attr), &redirect_pointer,
sizeof(redirect_pointer));
values[i] = PointerGetDatum(new_attr);
}
newtup = heap_form_tuple(tupdesc, values, nulls);
pfree(values);
pfree(nulls);
ReleaseTupleDesc(tupdesc);
MemoryContextSwitchTo(old_context);
PG_RETURN_HEAPTUPLEHEADER(newtup->t_data);
}
