crypto: add addCipherPrototypeFunctions function

This commit adds a function named addCipherPrototypeFunctions to avoid
code duplication.

lib/internal/crypto/cipher.js

@@ -236,17 +236,19 @@ function Cipheriv(cipher, key, iv, options) {
   createCipherWithIV.call(this, cipher, key, options, true, iv);
 }
 
-inherits(Cipheriv, LazyTransform);
-
-Cipheriv.prototype._transform = Cipher.prototype._transform;
-Cipheriv.prototype._flush = Cipher.prototype._flush;
-Cipheriv.prototype.update = Cipher.prototype.update;
-Cipheriv.prototype.final = Cipher.prototype.final;
-Cipheriv.prototype.setAutoPadding = Cipher.prototype.setAutoPadding;
-Cipheriv.prototype.getAuthTag = Cipher.prototype.getAuthTag;
-Cipheriv.prototype.setAuthTag = Cipher.prototype.setAuthTag;
-Cipheriv.prototype.setAAD = Cipher.prototype.setAAD;
+function addCipherPrototypeFunctions(constructor) {
+  constructor.prototype._transform = Cipher.prototype._transform;
+  constructor.prototype._flush = Cipher.prototype._flush;
+  constructor.prototype.update = Cipher.prototype.update;
+  constructor.prototype.final = Cipher.prototype.final;
+  constructor.prototype.setAutoPadding = Cipher.prototype.setAutoPadding;
+  constructor.prototype.getAuthTag = Cipher.prototype.getAuthTag;
+  constructor.prototype.setAuthTag = Cipher.prototype.setAuthTag;
+  constructor.prototype.setAAD = Cipher.prototype.setAAD;
+}
 
+inherits(Cipheriv, LazyTransform);
+addCipherPrototypeFunctions(Cipheriv);
 
 function Decipher(cipher, password, options) {
   if (!(this instanceof Decipher))
@@ -256,15 +258,7 @@ function Decipher(cipher, password, options) {
 }
 
 inherits(Decipher, LazyTransform);
-
-Decipher.prototype._transform = Cipher.prototype._transform;
-Decipher.prototype._flush = Cipher.prototype._flush;
-Decipher.prototype.update = Cipher.prototype.update;
-Decipher.prototype.final = Cipher.prototype.final;
-Decipher.prototype.setAutoPadding = Cipher.prototype.setAutoPadding;
-Decipher.prototype.getAuthTag = Cipher.prototype.getAuthTag;
-Decipher.prototype.setAuthTag = Cipher.prototype.setAuthTag;
-Decipher.prototype.setAAD = Cipher.prototype.setAAD;
+addCipherPrototypeFunctions(Decipher);
 
 
 function Decipheriv(cipher, key, iv, options) {
@@ -275,16 +269,7 @@ function Decipheriv(cipher, key, iv, options) {
 }
 
 inherits(Decipheriv, LazyTransform);
-
-Decipheriv.prototype._transform = Cipher.prototype._transform;
-Decipheriv.prototype._flush = Cipher.prototype._flush;
-Decipheriv.prototype.update = Cipher.prototype.update;
-Decipheriv.prototype.final = Cipher.prototype.final;
-Decipheriv.prototype.setAutoPadding = Cipher.prototype.setAutoPadding;
-Decipheriv.prototype.getAuthTag = Cipher.prototype.getAuthTag;
-Decipheriv.prototype.setAuthTag = Cipher.prototype.setAuthTag;
-Decipheriv.prototype.setAAD = Cipher.prototype.setAAD;
-
+addCipherPrototypeFunctions(Decipheriv);
 
 module.exports = {
   Cipher,