lntypes/preimage: add MakePreimage initializer

lntypes/preimage.go

@@ -9,8 +9,8 @@ import (
 // PreimageSize of array used to store preimagees.
 const PreimageSize = 32
 
-// Preimage is used in several of the lightning messages and common structures. It
-// represents a payment preimage.
+// Preimage is used in several of the lightning messages and common structures.
+// It represents a payment preimage.
 type Preimage [PreimageSize]byte
 
 // String returns the Preimage as a hexadecimal string.
@@ -18,35 +18,35 @@ func (p Preimage) String() string {
 	return hex.EncodeToString(p[:])
 }
 
-// NewPreimage returns a new Preimage from a byte slice.  An error is returned if
-// the number of bytes passed in is not PreimageSize.
-func NewPreimage(newPreimage []byte) (*Preimage, error) {
+// MakePreimage returns a new Preimage from a bytes slice. An error is returned
+// if the number of bytes passed in is not PreimageSize.
+func MakePreimage(newPreimage []byte) (Preimage, error) {
 	nhlen := len(newPreimage)
 	if nhlen != PreimageSize {
-		return nil, fmt.Errorf("invalid preimage length of %v, want %v",
-			nhlen, PreimageSize)
+		return Preimage{}, fmt.Errorf("invalid preimage length of %v, "+
+			"want %v", nhlen, PreimageSize)
 	}
 
 	var preimage Preimage
 	copy(preimage[:], newPreimage)
 
-	return &preimage, nil
+	return preimage, nil
 }
 
-// NewPreimageFromStr creates a Preimage from a hex preimage string.
-func NewPreimageFromStr(newPreimage string) (*Preimage, error) {
+// MakePreimageFromStr creates a Preimage from a hex preimage string.
+func MakePreimageFromStr(newPreimage string) (Preimage, error) {
 	// Return error if preimage string is of incorrect length.
 	if len(newPreimage) != PreimageSize*2 {
-		return nil, fmt.Errorf("invalid preimage string length of %v, "+
-			"want %v", len(newPreimage), PreimageSize*2)
+		return Preimage{}, fmt.Errorf("invalid preimage string length "+
+			"of %v, want %v", len(newPreimage), PreimageSize*2)
 	}
 
 	preimage, err := hex.DecodeString(newPreimage)
 	if err != nil {
-		return nil, err
+		return Preimage{}, err
 	}
 
-	return NewPreimage(preimage)
+	return MakePreimage(preimage)
 }
 
 // Hash returns the sha256 hash of the preimage.