Refactor utils/utils, fixes #11923

Signed-off-by: Antonio Murdaca <me@runcom.ninja>

ioutils/readers.go

@@ -3,6 +3,8 @@ package ioutils
 import (
 	"bytes"
 	"crypto/rand"
+	"crypto/sha256"
+	"encoding/hex"
 	"io"
 	"math/big"
 	"sync"
@@ -215,3 +217,11 @@ func (r *bufReader) Close() error {
 	}
 	return closer.Close()
 }
+
+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
+}

ioutils/writers.go

@@ -37,3 +37,24 @@ func NewWriteCloserWrapper(r io.Writer, closer func() error) io.WriteCloser {
 		closer: closer,
 	}
 }
+
+// Wrap a concrete io.Writer and hold a count of the number
+// of bytes written to the writer during a "session".
+// This can be convenient when write return is masked
+// (e.g., json.Encoder.Encode())
+type WriteCounter struct {
+	Count  int64
+	Writer io.Writer
+}
+
+func NewWriteCounter(w io.Writer) *WriteCounter {
+	return &WriteCounter{
+		Writer: w,
+	}
+}
+
+func (wc *WriteCounter) Write(p []byte) (count int, err error) {
+	count, err = wc.Writer.Write(p)
+	wc.Count += int64(count)
+	return
+}

ioutils/writers_test.go

@@ -0,0 +1,41 @@
+package ioutils
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+)
+
+func TestNopWriter(t *testing.T) {
+	nw := &NopWriter{}
+	l, err := nw.Write([]byte{'c'})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if l != 1 {
+		t.Fatalf("Expected 1 got %d", l)
+	}
+}
+
+func TestWriteCounter(t *testing.T) {
+	dummy1 := "This is a dummy string."
+	dummy2 := "This is another dummy string."
+	totalLength := int64(len(dummy1) + len(dummy2))
+
+	reader1 := strings.NewReader(dummy1)
+	reader2 := strings.NewReader(dummy2)
+
+	var buffer bytes.Buffer
+	wc := NewWriteCounter(&buffer)
+
+	reader1.WriteTo(wc)
+	reader2.WriteTo(wc)
+
+	if wc.Count != totalLength {
+		t.Errorf("Wrong count: %d vs. %d", wc.Count, totalLength)
+	}
+
+	if buffer.String() != dummy1+dummy2 {
+		t.Error("Wrong message written")
+	}
+}