gitea/vendor/github.com/pingcap/tidb/evaluator/helper.go

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package evaluator
import (
"strconv"
"strings"
"time"
"github.com/juju/errors"
"github.com/pingcap/tidb/ast"
"github.com/pingcap/tidb/context"
"github.com/pingcap/tidb/mysql"
"github.com/pingcap/tidb/sessionctx/variable"
"github.com/pingcap/tidb/util/types"
)
var (
// CurrentTimestamp is the keyword getting default value for datetime and timestamp type.
CurrentTimestamp = "CURRENT_TIMESTAMP"
currentTimestampL = "current_timestamp"
// ZeroTimestamp shows the zero datetime and timestamp.
ZeroTimestamp = "0000-00-00 00:00:00"
)
var (
errDefaultValue = errors.New("invalid default value")
)
// GetTimeValue gets the time value with type tp.
func GetTimeValue(ctx context.Context, v interface{}, tp byte, fsp int) (interface{}, error) {
return getTimeValue(ctx, v, tp, fsp)
}
func getTimeValue(ctx context.Context, v interface{}, tp byte, fsp int) (interface{}, error) {
value := mysql.Time{
Type: tp,
Fsp: fsp,
}
defaultTime, err := getSystemTimestamp(ctx)
if err != nil {
return nil, errors.Trace(err)
}
switch x := v.(type) {
case string:
upperX := strings.ToUpper(x)
if upperX == CurrentTimestamp {
value.Time = defaultTime
} else if upperX == ZeroTimestamp {
value, _ = mysql.ParseTimeFromNum(0, tp, fsp)
} else {
value, err = mysql.ParseTime(x, tp, fsp)
if err != nil {
return nil, errors.Trace(err)
}
}
case *ast.ValueExpr:
switch x.Kind() {
case types.KindString:
value, err = mysql.ParseTime(x.GetString(), tp, fsp)
if err != nil {
return nil, errors.Trace(err)
}
case types.KindInt64:
value, err = mysql.ParseTimeFromNum(x.GetInt64(), tp, fsp)
if err != nil {
return nil, errors.Trace(err)
}
case types.KindNull:
return nil, nil
default:
return nil, errors.Trace(errDefaultValue)
}
case *ast.FuncCallExpr:
if x.FnName.L == currentTimestampL {
return CurrentTimestamp, nil
}
return nil, errors.Trace(errDefaultValue)
case *ast.UnaryOperationExpr:
// support some expression, like `-1`
v, err := Eval(ctx, x)
if err != nil {
return nil, errors.Trace(err)
}
ft := types.NewFieldType(mysql.TypeLonglong)
xval, err := types.Convert(v, ft)
if err != nil {
return nil, errors.Trace(err)
}
value, err = mysql.ParseTimeFromNum(xval.(int64), tp, fsp)
if err != nil {
return nil, errors.Trace(err)
}
default:
return nil, nil
}
return value, nil
}
// IsCurrentTimeExpr returns whether e is CurrentTimeExpr.
func IsCurrentTimeExpr(e ast.ExprNode) bool {
x, ok := e.(*ast.FuncCallExpr)
if !ok {
return false
}
return x.FnName.L == currentTimestampL
}
func getSystemTimestamp(ctx context.Context) (time.Time, error) {
value := time.Now()
if ctx == nil {
return value, nil
}
// check whether use timestamp varibale
sessionVars := variable.GetSessionVars(ctx)
if v, ok := sessionVars.Systems["timestamp"]; ok {
if v != "" {
timestamp, err := strconv.ParseInt(v, 10, 64)
if err != nil {
return time.Time{}, errors.Trace(err)
}
if timestamp <= 0 {
return value, nil
}
return time.Unix(timestamp, 0), nil
}
}
return value, nil
}