craban/server/vendor/github.com/Masterminds/squirrel/part.go

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package squirrel
import (
"fmt"
"io"
)
type part struct {
pred interface{}
args []interface{}
}
func newPart(pred interface{}, args ...interface{}) Sqlizer {
return &part{pred, args}
}
func (p part) ToSql() (sql string, args []interface{}, err error) {
switch pred := p.pred.(type) {
case nil:
// no-op
case Sqlizer:
sql, args, err = pred.ToSql()
case string:
sql = pred
args = p.args
default:
err = fmt.Errorf("expected string or Sqlizer, not %T", pred)
}
return
}
func appendToSql(parts []Sqlizer, w io.Writer, sep string, args []interface{}) ([]interface{}, error) {
for i, p := range parts {
partSql, partArgs, err := p.ToSql()
if err != nil {
return nil, err
} else if len(partSql) == 0 {
continue
}
if i > 0 {
_, err := io.WriteString(w, sep)
if err != nil {
return nil, err
}
}
_, err = io.WriteString(w, partSql)
if err != nil {
return nil, err
}
args = append(args, partArgs...)
}
return args, nil
}