/
local.go
54 lines (42 loc) · 1.15 KB
/
local.go
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package files
import (
"io"
"os"
"strings"
"github.com/pkg/errors"
)
type LocalFileHelper struct{}
// NewReader creates a new Reader for local file.
func (h *LocalFileHelper) NewReader(uri string) (io.Reader, error) {
schemePrefix := FileScheme + "://"
if strings.HasPrefix(uri, schemePrefix) {
uri = uri[len(schemePrefix):]
}
reader, err := os.Open(uri)
if err != nil {
return nil, errors.WithStack(errors.Wrapf(err, "Could not read: %v", uri))
}
return reader, nil
}
// NewWriter creates a new Writer for the local file.
//
// TODO(jlewi): Can we add options to control filemode?
func (h *LocalFileHelper) NewWriter(uri string) (io.Writer, error) {
_, err := os.Stat(uri)
if err == nil || !os.IsNotExist(err) {
return nil, errors.WithStack(errors.Errorf("Can't write %v; It already exists", uri))
}
writer, err := os.Create(uri)
if err != nil {
return nil, errors.WithStack(errors.Wrapf(err, "Could not write: %v", uri))
}
return writer, nil
}
// Exists checks whether the file exists.
func (h *LocalFileHelper) Exists(uri string) (bool, error) {
_, err := os.Stat(uri)
if os.IsNotExist(err) {
return false, nil
}
return true, nil
}