func FormHeapTuple(values []system.Datum, tupdesc *TupleDesc) *HeapTuple {
natts := len(tupdesc.Attrs)
hasnull := false
for _, value := range values {
if value == nil {
hasnull = true
//} else if att.attlen == -1
// TODO: flatten toast value
}
}
length := unsafe.Offsetof(HeapTupleHeader{}.bits)
if hasnull {
length += uintptr(bitmapLength(natts))
}
if tupdesc.hasOid {
length += unsafe.Sizeof(system.Oid(0))
}
length = system.MaxAlign(length)
hoff := uint8(length)
data_len := computeHeapDataSize(values, tupdesc)
length += data_len
tuple_data := make([]byte, length)
tuple := &HeapTuple{
tupdesc: tupdesc,
tableOid: system.InvalidOid,
}
tuple.SetData(tuple_data, system.InvalidItemPointer)
td := tuple.data
td.SetNatts(system.AttrNumber(natts))
td.hoff = hoff
if tupdesc.hasOid {
td.infomask = heapHasOid
}
bits := []byte(nil)
if hasnull {
bits = tuple.bytes[unsafe.Offsetof(td.bits):hoff]
}
data := tuple.bytes[hoff:]
td.fill(values, tupdesc, bits, data)
return tuple
}
func (tuple *HeapTuple) Fetch(attnum system.AttrNumber) system.Datum {
if attnum <= 0 {
switch attnum {
case system.CtidAttrNumber:
return system.Datum(tuple.self)
case system.OidAttrNumber:
return system.Datum(tuple.data.Oid())
case system.XminAttrNumber:
//return system.Datum(tuple.data.Xmin())
case system.CminAttrNumber:
// TODO:
case system.XmaxAttrNumber:
//return system.Datum(tuple.data.Xmax())
case system.CmaxAttrNumber:
// TODO:
case system.TableOidAttrNumber:
return system.Datum(tuple.tableOid)
}
} else {
td := tuple.data
if td.IsNull(attnum) {
return nil
}
// TODO: attcache
offset := int(td.hoff)
for i := system.AttrNumber(1); i < attnum; i++ {
if td.IsNull(i) {
continue
}
attr := tuple.tupdesc.Attrs[i-1]
if attr.Type.IsVarlen() {
// TODO:
} else {
offset += int(attr.Type.Len)
}
}
reader := bytes.NewReader(tuple.bytes[offset:])
return system.DatumFromBytes(reader, tuple.tupdesc.Attrs[attnum-1].TypeId)
}
return nil
}
func (s *MySuite) TestHeapTuple(c *C) {
values := []system.Datum{
system.Int4(1),
system.Oid(999990),
nil,
system.Name("fooname"),
}
tupdesc := &TupleDesc{
Attrs: []*Attribute{
{
Name: "col1",
TypeId: system.Int4Type,
},
{
Name: "col2",
TypeId: system.OidType,
},
{
Name: "col3nil",
TypeId: system.NameType,
},
{
Name: "col4",
TypeId: system.NameType,
},
},
}
initTupleDesc(tupdesc)
htuple := FormHeapTuple(values, tupdesc)
c.Check(htuple.Fetch(1), Equals, values[0])
c.Check(htuple.Fetch(2), Equals, values[1])
c.Check(htuple.Fetch(3), Equals, values[2])
c.Check(htuple.Fetch(4), Equals, values[3])
c.Check(htuple.data.Oid(), Equals, system.InvalidOid)
c.Check(htuple.data.HasNulls(), Equals, true)
c.Check(htuple.data.Natts(), Equals, system.AttrNumber(4))
}
func (htup *HeapTupleHeader) Natts() system.AttrNumber {
return system.AttrNumber(htup.infomask2 & uint16(heapNattsMask))
}
