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readers.go
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/
readers.go
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package ioutils
import (
"crypto/sha256"
"encoding/hex"
"io"
)
type readCloserWrapper struct {
io.Reader
closer func() error
}
func (r *readCloserWrapper) Close() error {
return r.closer()
}
// NewReadCloserWrapper returns a new io.ReadCloser.
func NewReadCloserWrapper(r io.Reader, closer func() error) io.ReadCloser {
return &readCloserWrapper{
Reader: r,
closer: closer,
}
}
type readerErrWrapper struct {
reader io.Reader
closer func()
}
func (r *readerErrWrapper) Read(p []byte) (int, error) {
n, err := r.reader.Read(p)
if err != nil {
r.closer()
}
return n, err
}
// NewReaderErrWrapper returns a new io.Reader.
func NewReaderErrWrapper(r io.Reader, closer func()) io.Reader {
return &readerErrWrapper{
reader: r,
closer: closer,
}
}
// HashData returns the sha256 sum of src.
func HashData(src io.Reader) (string, error) {
h := sha256.New()
if _, err := io.Copy(h, src); err != nil {
return "", err
}
return "sha256:" + hex.EncodeToString(h.Sum(nil)), nil
}
// OnEOFReader wraps a io.ReadCloser and a function
// the function will run at the end of file or close the file.
type OnEOFReader struct {
Rc io.ReadCloser
Fn func()
}
func (r *OnEOFReader) Read(p []byte) (n int, err error) {
n, err = r.Rc.Read(p)
if err == io.EOF {
r.runFunc()
}
return
}
// Close closes the file and run the function.
func (r *OnEOFReader) Close() error {
err := r.Rc.Close()
r.runFunc()
return err
}
func (r *OnEOFReader) runFunc() {
if fn := r.Fn; fn != nil {
fn()
r.Fn = nil
}
}