Fix uint8array check

Author: graup

binary/utils.js

@@ -1051,11 +1051,6 @@ jspb.utils.byteSourceToUint8Array = function(data) {
     return /** @type {!Uint8Array} */(new Uint8Array(data));
   }
 
-  if (typeof Buffer != 'undefined' && data.constructor === Buffer) {
-    return /** @type {!Uint8Array} */ (
-        new Uint8Array(/** @type {?} */ (data)));
-  }
-
   if (data.constructor === Array) {
     data = /** @type {!Array<number>} */(data);
     return /** @type {!Uint8Array} */(new Uint8Array(data));
@@ -1066,6 +1061,15 @@ jspb.utils.byteSourceToUint8Array = function(data) {
     return goog.crypt.base64.decodeStringToUint8Array(data);
   }
 
+  if (data instanceof Uint8Array) {
+    // Support types like nodejs Buffer and other subclasses of Uint8Array.
+    data = /** @type {!Uint8Array} */ (data);
+    // Make a shallow copy to ensure we only ever deal with Uint8Array
+    // exactly to ensure monomorphism.
+    return /** @type {!Uint8Array} */ (
+        new Uint8Array(data.buffer, data.byteOffset, data.byteLength));
+  }
+
   goog.asserts.fail('Type not convertible to Uint8Array.');
   return /** @type {!Uint8Array} */(new Uint8Array(0));
 };

binary/utils_test.js

@@ -719,7 +719,6 @@ describe('binaryUtilsTest', function() {
     var sourceBytes = new Uint8Array(sourceData);
     var sourceBuffer = sourceBytes.buffer;
     var sourceBase64 = goog.crypt.base64.encodeByteArray(sourceData);
-    var sourceString = goog.crypt.byteArrayToString(sourceData);
 
     function check(result) {
       expect(result.constructor).toEqual(Uint8Array);
@@ -740,5 +739,8 @@ describe('binaryUtilsTest', function() {
 
     // Converting base64-encoded strings into Uint8Arrays should work.
     check(convert(sourceBase64));
+
+    // Existing Uint8Array into Uint8Arrays should work.
+    check(convert(sourceUint8Array));
   });
 });