JS: parse (un)packed fields conditionally (#7379)

Author: qnighy

binary/reader.js

@@ -206,6 +206,15 @@ jspb.BinaryReader.prototype.getWireType = function() {
 };
 
 
+/**
+ * @return {boolean} Whether the current wire type is a delimited field. Used to
+ * conditionally parse packed repeated fields.
+ */
+jspb.BinaryReader.prototype.isDelimited = function() {
+  return this.nextWireType_ == jspb.BinaryConstants.WireType.DELIMITED;
+};
+
+
 /**
  * @return {boolean} Whether the current wire type is an end-group tag. Used as
  * an exit condition in decoder loops in generated code.

src/google/protobuf/compiler/js/js_generator.cc

@@ -3163,6 +3163,16 @@ void Generator::GenerateClassDeserializeBinaryField(
           (field->type() == FieldDescriptor::TYPE_GROUP)
               ? (StrCat(field->number()) + ", ")
               : "");
+    } else if (field->is_packable()) {
+      printer->Print(
+          "      var values = /** @type {$fieldtype$} */ "
+          "(reader.isDelimited() "
+          "? reader.readPacked$reader$() : [reader.read$reader$()]);\n",
+          "fieldtype",
+          JSFieldTypeAnnotation(options, field, false, true,
+                                /* singular_if_not_packed */ false, BYTES_U8),
+          "reader",
+          JSBinaryReaderMethodType(field));
     } else {
       printer->Print(
           "      var value = /** @type {$fieldtype$} */ "
@@ -3174,7 +3184,13 @@ void Generator::GenerateClassDeserializeBinaryField(
           JSBinaryReadWriteMethodName(field, /* is_writer = */ false));
     }
 
-    if (field->is_repeated() && !field->is_packed()) {
+    if (field->is_packable()) {
+      printer->Print(
+          "      for (var i = 0; i < values.length; i++) {\n"
+          "        msg.add$name$(values[i]);\n"
+          "      }\n", "name",
+          JSGetterName(options, field, BYTES_DEFAULT, /* drop_list = */ true));
+    } else if (field->is_repeated()) {
       printer->Print(
           "      msg.add$name$(value);\n", "name",
           JSGetterName(options, field, BYTES_DEFAULT, /* drop_list = */ true));