func ReadDataRow(m *Message) (*DataRow, error) {
if t := m.MsgType(); t != MsgDataRowD {
return nil, e.BadTypeCode(t)
}
b := m.Payload()
fieldCount, err := ReadUint16(b)
if err != nil {
return nil, err
}
values := make([][]byte, fieldCount)
for i := range values {
fieldLen, err := ReadInt32(b)
if err != nil {
return nil, err
}
if fieldLen >= 0 {
fieldData := make([]byte, fieldLen)
io.ReadFull(b, fieldData)
values[i] = fieldData
} else if fieldLen == -1 {
values[i] = nil
} else {
return nil, e.WrongSize("Invalid length %v for field %v",
fieldLen, i)
}
}
return &DataRow{values}, nil
}
func ReadCancelRequest(m *Message) (*CancelRequest, error) {
var err error
body, err := readFirst(m)
if size := m.Size() - 4; size != 12 {
return nil, e.WrongSize(
"expected CancelRequest to be 12 bytes; got %v",
size,
)
}
var b Reader
b.InitReader(body)
if code, _ := ReadUint32(&b); code != 80877102 {
return nil, fmt.Errorf(
"expected cancel message code 80877102; got %v",
code,
)
}
bePid, err := ReadUint32(&b)
if err != nil {
return nil, err
}
secret, err := ReadUint32(&b)
if err != nil {
return nil, err
}
return &CancelRequest{BackendPid: bePid, SecretKey: secret}, nil
}
// Read the first message from a client: either a StartupMessage or a CancelRequest
func readFirst(m *Message) ([]byte, error) {
if remainingSz := m.Size() - 4; remainingSz > 10000 {
// Startup packets longer than this are considered
// invalid. Copied from the PostgreSQL source code.
err := e.TooBig(
"Rejecting oversized startup packet: got %v",
m.Size())
return nil, err
} else if remainingSz < 4 {
// We expect all initialization messages to
// have at least a 4-byte header
err := e.WrongSize(
"Expected message of at least 4 bytes; got %v",
remainingSz)
return nil, err
}
return m.Force()
}
func ReadBackendKeyData(msg *Message) (*BackendKeyData, error) {
if t := msg.MsgType(); t != MsgBackendKeyDataK {
return nil, e.BadTypeCode(t)
}
const RIGHT_SZ = 12
if msg.Size() != RIGHT_SZ {
return nil, e.WrongSize("BackendKeyData is wrong size: "+
"expected %v, got %v", RIGHT_SZ, msg.Size())
}
r := msg.Payload()
pid, err := ReadUint32(r)
if err != nil {
return nil, err
}
key, err := ReadUint32(r)
if err != nil {
return nil, err
}
return &BackendKeyData{BackendPid: pid, SecretKey: key}, err
}
