forked from dropbox/godropbox
/
temporal_fields.go
255 lines (214 loc) · 5.67 KB
/
temporal_fields.go
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package binlog
import (
"time"
"github.com/dropbox/godropbox/errors"
mysql_proto "github.com/dropbox/godropbox/proto/mysql"
)
// This contains field descriptors for temporal types as defined by
// sql/field.h. In particular:
//
// Field (abstract)
// |
// ...
// | +--Field_year
// ...
// |
// +--Field_temporal (abstract)
// +--Field_time_common (abstract)
// | +--Field_time
// | +--Field_timef
// |
// +--Field_temporal_with_date (abstract)
// +--Field_newdate
// +--Field_temporal_with_date_and_time (abstract)
// +--Field_timestamp
// +--Field_datetime
// +--Field_temporal_with_date_and_timef (abstract)
// +--Field_timestampf
// +--Field_datetimef
// This returns a field descriptor for FieldType_YEAR (i.e., Field_year)
func NewYearFieldDescriptor(nullable NullableColumn) FieldDescriptor {
return newFixedLengthFieldDescriptor(
mysql_proto.FieldType_YEAR,
nullable,
1,
func(b []byte) interface{} {
return time.Date(int(b[0])+1900, 0, 0, 0, 0, 0, 0, time.UTC)
})
}
// This returns a fields descriptor for FieldType_TIMESTAMP
// (i.e., Field_timestamp)
func NewTimestampFieldDescriptor(nullable NullableColumn) FieldDescriptor {
return newFixedLengthFieldDescriptor(
mysql_proto.FieldType_TIMESTAMP,
nullable,
4,
func(b []byte) interface{} {
return time.Unix(int64(LittleEndian.Uint32(b)), 0).UTC()
})
}
// This returns a fields descriptor for FieldType_DATETIME
// (i.e., Field_datetime). See number_to_datetime (in sql-common/my_time.c)
// for encoding detail.
func NewDateTimeFieldDescriptor(nullable NullableColumn) FieldDescriptor {
return newFixedLengthFieldDescriptor(
mysql_proto.FieldType_DATETIME,
nullable,
8,
func(b []byte) interface{} {
val := LittleEndian.Uint64(b)
d := val / 1000000
t := val % 1000000
return time.Date(
int(d/10000), // year
time.Month((d%10000)/100), // month
int(d%100), // day
int(t/10000), // hour
int((t%10000)/100), // minute
int(t%100), // second
0, // nanosecond
time.UTC)
})
}
// Common functionality for datetime2 and timestamp2
type usecTemporalFieldDescriptor struct {
baseFieldDescriptor
microSecondPrecision uint8
fixedSize int
neededBytes int
}
func (d *usecTemporalFieldDescriptor) init(
fieldType mysql_proto.FieldType_Type,
nullable NullableColumn,
fixedSize int,
metadata []byte) (
remaining []byte,
err error) {
d.fieldType = fieldType
d.isNullable = nullable
if len(metadata) < 1 {
return nil, errors.New("Metadata has too few bytes")
}
d.fixedSize = fixedSize
d.neededBytes = fixedSize
d.microSecondPrecision = uint8(metadata[0])
switch d.microSecondPrecision {
case 0:
// do nothing
case 1, 2:
d.neededBytes++
case 3, 4:
d.neededBytes += 2
case 5, 6:
d.neededBytes += 3
default:
return nil, errors.New("Invalid usec precision")
}
return metadata[1:], nil
}
func (d *usecTemporalFieldDescriptor) readData(data []byte) (
fixedBytes []byte,
msec int64,
remaining []byte,
err error) {
raw, remaining, err := readSlice(data, d.neededBytes)
if err != nil {
return nil, 0, nil, err
}
msecBytes := raw[d.fixedSize:]
msec = int64(0)
switch d.microSecondPrecision {
case 0:
// do nothing
case 1, 2:
msec = int64(BigEndian.Int8(msecBytes)) * 10000
case 3, 4:
msec = int64(BigEndian.Int16(msecBytes)) * 100
case 5, 6:
msec = int64(BigEndian.Int24(msecBytes))
}
return raw[:d.fixedSize], msec, remaining, nil
}
type timestamp2FieldDescriptor struct {
usecTemporalFieldDescriptor
}
// This returns a field descriptor for FieldType_TIMESTAMP2
// (i.e., Field_timestampf). See my_timestamp_from_binary (in
// sql-common/my_time.c) for encoding detail.
func NewTimestamp2FieldDescriptor(nullable NullableColumn, metadata []byte) (
fd FieldDescriptor,
remaining []byte,
err error) {
t := ×tamp2FieldDescriptor{}
remaining, err = t.init(
mysql_proto.FieldType_TIMESTAMP2,
nullable,
4,
metadata)
if err != nil {
return nil, nil, err
}
return t, remaining, nil
}
func (d *timestamp2FieldDescriptor) ParseValue(data []byte) (
value interface{},
remaining []byte,
err error) {
secBytes, msec, remaining, err := d.readData(data)
if err != nil {
return nil, nil, err
}
sec := int64(BigEndian.Int32(secBytes))
return time.Unix(sec, msec*1000).UTC(), remaining, nil
}
// equivalent to DATETIMEF_INT_OFS
const datetimefIntOffset = 0x8000000000
type datetime2FieldDescriptor struct {
usecTemporalFieldDescriptor
}
// This returns a field descriptor for FieldType_DATETIME2
// (i.e., Field_datetimef). See TIME_from_longlong_datetime_packed (
// in sql-common/my_time.c) for encoding detail.
func NewDateTime2FieldDescriptor(nullable NullableColumn, metadata []byte) (
fd FieldDescriptor,
reamining []byte,
err error) {
d := &datetime2FieldDescriptor{}
remaining, err := d.init(
mysql_proto.FieldType_DATETIME2,
nullable,
5,
metadata)
if err != nil {
return nil, nil, err
}
return d, remaining, nil
}
func (d *datetime2FieldDescriptor) ParseValue(data []byte) (
value interface{},
remaining []byte,
err error) {
dtBytes, msec, remaining, err := d.readData(data)
if err != nil {
return nil, nil, err
}
ymdhms := BigEndian.Uint40(dtBytes) - datetimefIntOffset
ymd := ymdhms >> 17
ym := ymd >> 5
hms := ymdhms % (1 << 17)
day := ymd % (1 << 5)
month := ym % 13
year := ym / 13
second := hms % (1 << 6)
minute := (hms >> 6) % (1 << 6)
hour := hms >> 12
return time.Date(
int(year),
time.Month(month),
int(day),
int(hour),
int(minute),
int(second),
int(msec)*1000, // nanosecond
time.UTC), remaining, nil
}