Andrea Maria Piana 4ab08629f6 Add postgres
This commits adds support for postgres database.
Currently two fields are stored: the bloom filter and the topic.
Only the bloom filter is actually used to query, but potentially we will
use also the topic in the future, so easier to separate it now in order
to avoid a migration.
2019-05-15 11:01:34 +02:00

94 lines
2.4 KiB
Go

package pq
import (
"math"
"reflect"
"time"
"github.com/lib/pq/oid"
)
const headerSize = 4
type fieldDesc struct {
// The object ID of the data type.
OID oid.Oid
// The data type size (see pg_type.typlen).
// Note that negative values denote variable-width types.
Len int
// The type modifier (see pg_attribute.atttypmod).
// The meaning of the modifier is type-specific.
Mod int
}
func (fd fieldDesc) Type() reflect.Type {
switch fd.OID {
case oid.T_int8:
return reflect.TypeOf(int64(0))
case oid.T_int4:
return reflect.TypeOf(int32(0))
case oid.T_int2:
return reflect.TypeOf(int16(0))
case oid.T_varchar, oid.T_text:
return reflect.TypeOf("")
case oid.T_bool:
return reflect.TypeOf(false)
case oid.T_date, oid.T_time, oid.T_timetz, oid.T_timestamp, oid.T_timestamptz:
return reflect.TypeOf(time.Time{})
case oid.T_bytea:
return reflect.TypeOf([]byte(nil))
default:
return reflect.TypeOf(new(interface{})).Elem()
}
}
func (fd fieldDesc) Name() string {
return oid.TypeName[fd.OID]
}
func (fd fieldDesc) Length() (length int64, ok bool) {
switch fd.OID {
case oid.T_text, oid.T_bytea:
return math.MaxInt64, true
case oid.T_varchar, oid.T_bpchar:
return int64(fd.Mod - headerSize), true
default:
return 0, false
}
}
func (fd fieldDesc) PrecisionScale() (precision, scale int64, ok bool) {
switch fd.OID {
case oid.T_numeric, oid.T__numeric:
mod := fd.Mod - headerSize
precision = int64((mod >> 16) & 0xffff)
scale = int64(mod & 0xffff)
return precision, scale, true
default:
return 0, 0, false
}
}
// ColumnTypeScanType returns the value type that can be used to scan types into.
func (rs *rows) ColumnTypeScanType(index int) reflect.Type {
return rs.colTyps[index].Type()
}
// ColumnTypeDatabaseTypeName return the database system type name.
func (rs *rows) ColumnTypeDatabaseTypeName(index int) string {
return rs.colTyps[index].Name()
}
// ColumnTypeLength returns the length of the column type if the column is a
// variable length type. If the column is not a variable length type ok
// should return false.
func (rs *rows) ColumnTypeLength(index int) (length int64, ok bool) {
return rs.colTyps[index].Length()
}
// ColumnTypePrecisionScale should return the precision and scale for decimal
// types. If not applicable, ok should be false.
func (rs *rows) ColumnTypePrecisionScale(index int) (precision, scale int64, ok bool) {
return rs.colTyps[index].PrecisionScale()
}