blob: e5dab997d56028302a238e435ebf439f91a2e886 [file] [log] [blame]
// Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
import 'package:protobuf/meta.dart';
import 'package:protoc_plugin/src/dart_options.pb.dart';
import 'package:protoc_plugin/src/descriptor.pb.dart';
/// A Dart function called on each item added to a repeated list
/// to check its type and range.
const checkItem = '\$checkItem';
/// The Dart member names in a GeneratedMessage subclass for one protobuf field.
class MemberNames {
/// The descriptor of the field these member names apply to.
final FieldDescriptorProto descriptor;
/// The index of this field in MessageGenerator.fieldList.
/// The same index will be stored in FieldInfo.index.
final int index;
/// Identifier for generated getters/setters.
final String fieldName;
/// Identifier for the generated hasX() method, without braces.
/// `null` for repeated fields.
final String hasMethodName;
/// Identifier for the generated clearX() method, without braces.
/// `null` for repeated fields.
final String clearMethodName;
MemberNames(this.descriptor, this.index, this.fieldName, this.hasMethodName,
MemberNames.forRepeatedField(this.descriptor, this.index, this.fieldName)
: hasMethodName = null,
clearMethodName = null;
/// Chooses the Dart name of an extension.
String extensionName(FieldDescriptorProto descriptor) {
var existingNames = new Set<String>()
return _unusedMemberNames(descriptor, null, existingNames).fieldName;
/// Chooses the name of the Dart class holding top-level extensions.
String extensionClassName(FileDescriptorProto descriptor) {
var taken = new Set<String>();
for (var messageType in descriptor.messageType) {
for (var enumType in descriptor.enumType) {
String s = _fileNameWithoutExtension(descriptor).replaceAll('-', '_');
String candidate = '${s[0].toUpperCase()}${s.substring(1)}';
if (!taken.contains(candidate)) {
return candidate;
// Found a conflict; try again.
candidate = "${candidate}Ext";
if (!taken.contains(candidate)) {
return candidate;
// Next, try numbers.
int suffix = 2;
while (taken.contains("$candidate$suffix")) {
return "$candidate$suffix";
String _fileNameWithoutExtension(FileDescriptorProto descriptor) {
Uri path = new Uri.file(;
String fileName = path.pathSegments.last;
int dot = fileName.lastIndexOf(".");
return dot == -1 ? fileName : fileName.substring(0, dot);
// Exception thrown when a field has an invalid 'dart_name' option.
class DartNameOptionException implements Exception {
final String message;
String toString() => "$message";
/// Chooses the name of the Dart class to generate for a proto message or enum.
/// For a nested message or enum, [parent] should be provided
/// with the name of the Dart class for the immediate parent.
String messageOrEnumClassName(String descriptorName, {String parent = ''}) {
var name = descriptorName;
if (parent != '') {
name = '${parent}_${descriptorName}';
if (name == 'Function') {
name = 'Function_'; // Avoid reserved word.
} else if (name == 'List') {
name = 'List_';
} else if (name.startsWith('Function_')) {
// Avoid any further name conflicts due to 'Function' rename (unlikely).
name = name + '_';
return name;
/// Returns the set of names reserved by the ProtobufEnum class and its
/// generated subclasses.
Set<String> get reservedEnumNames => new Set<String>()
/// Chooses the ProtobufEnum names for each value.
/// Since the values all have the same type as the containing enum class, it
/// does not require all the same checks as for message member names. Still,
/// it needs to be checked against a list of reserved names to avoid collisions.
String unusedEnumNames(String name, Set<String> existingNames) {
final suffix = '_';
while (existingNames.contains(name)) {
name += suffix;
return name;
/// Chooses the GeneratedMessage member names for each field.
/// Additional names to avoid can be supplied using [reserved].
/// (This should only be used for mixins.)
/// Returns a map from the field name in the .proto file to its
/// corresponding MemberNames.
/// Throws [DartNameOptionException] if a field has this option and
/// it's set to an invalid name.
Map<String, MemberNames> messageFieldNames(DescriptorProto descriptor,
{Iterable<String> reserved = const []}) {
var sorted = new List<FieldDescriptorProto>.from(descriptor.field)
..sort((FieldDescriptorProto a, FieldDescriptorProto b) {
if (a.number < b.number) return -1;
if (a.number > b.number) return 1;
throw "multiple fields defined for tag ${a.number} in ${}";
// Choose indexes first, based on their position in the sorted list.
var indexes = <String, int>{};
for (var field in sorted) {
var index = indexes.length;
indexes[] = index;
var existingNames = new Set<String>()
var memberNames = <String, MemberNames>{};
void takeNames(MemberNames chosen) {
memberNames[] = chosen;
if (chosen.hasMethodName != null) {
if (chosen.clearMethodName != null) {
// Handle fields with a dart_name option.
// They have higher priority than automatically chosen names.
// Explicitly setting a name that's already taken is a build error.
for (var field in sorted) {
if (_nameOption(field).isNotEmpty) {
descriptor, field, indexes[], existingNames));
// Then do other fields.
// They are automatically renamed until we find something unused.
for (var field in sorted) {
if (_nameOption(field).isEmpty) {
var index = indexes[];
takeNames(_unusedMemberNames(field, index, existingNames));
// Return a map with entries in sorted order.
var result = <String, MemberNames>{};
for (var field in sorted) {
result[] = memberNames[];
return result;
/// Chooses the member names for a field that has the 'dart_name' option.
/// If the explicitly-set Dart name is already taken, throw an exception.
/// (Fails the build.)
MemberNames _memberNamesFromOption(DescriptorProto message,
FieldDescriptorProto field, int index, Set<String> existingNames) {
// TODO(skybrian): provide more context in errors (filename).
var where = "${}.${}";
void checkAvailable(String name) {
if (existingNames.contains(name)) {
throw new DartNameOptionException(
"$where: dart_name option is invalid: '$name' is already used");
var name = _nameOption(field);
if (name.isEmpty) {
throw new ArgumentError("field doesn't have dart_name option");
if (!_isDartFieldName(name)) {
throw new DartNameOptionException("$where: dart_name option is invalid: "
"'$name' is not a valid Dart field name");
if (_isRepeated(field)) {
return new MemberNames.forRepeatedField(field, index, name);
String hasMethod = "has${_capitalize(name)}";
String clearMethod = "clear${_capitalize(name)}";
return new MemberNames(field, index, name, hasMethod, clearMethod);
MemberNames _unusedMemberNames(
FieldDescriptorProto field, int index, Set<String> existingNames) {
var suffix = '_' + field.number.toString();
if (_isRepeated(field)) {
var name = _defaultFieldName(field);
while (existingNames.contains(name)) {
name += suffix;
return new MemberNames.forRepeatedField(field, index, name);
String name = _defaultFieldName(field);
String hasMethod = _defaultHasMethodName(field);
String clearMethod = _defaultClearMethodName(field);
while (existingNames.contains(name) ||
existingNames.contains(hasMethod) ||
existingNames.contains(clearMethod)) {
name += suffix;
hasMethod += suffix;
clearMethod += suffix;
return new MemberNames(field, index, name, hasMethod, clearMethod);
/// The name to use by default for the Dart getter and setter.
/// (A suffix will be added if there is a conflict.)
String _defaultFieldName(FieldDescriptorProto field) {
String name = _fieldMethodSuffix(field);
return '${name[0].toLowerCase()}${name.substring(1)}';
String _defaultHasMethodName(FieldDescriptorProto field) =>
String _defaultClearMethodName(FieldDescriptorProto field) =>
/// The suffix to use for this field in Dart method names.
/// (It should be camelcase and begin with an uppercase letter.)
String _fieldMethodSuffix(FieldDescriptorProto field) {
var name = _nameOption(field);
if (name.isNotEmpty) return _capitalize(name);
if (field.type != FieldDescriptorProto_Type.TYPE_GROUP) {
return _underscoresToCamelCase(;
// For groups, use capitalization of 'typeName' rather than 'name'.
name = field.typeName;
int index = name.lastIndexOf('.');
if (index != -1) {
name = name.substring(index + 1);
return _underscoresToCamelCase(name);
String _underscoresToCamelCase(s) => s.split('_').map(_capitalize).join('');
String _capitalize(s) =>
s.isEmpty ? s : '${s[0].toUpperCase()}${s.substring(1)}';
bool _isRepeated(FieldDescriptorProto field) =>
field.label == FieldDescriptorProto_Label.LABEL_REPEATED;
String _nameOption(FieldDescriptorProto field) =>
bool _isDartFieldName(name) => name.startsWith(_dartFieldNameExpr);
final _dartFieldNameExpr = new RegExp(r'^[a-z]\w+$');
// List of Dart language reserved words in names which cannot be used in a
// subclass of GeneratedMessage.
const List<String> _dartReservedWords = const [
// List of names used in the generated message classes.
// This is in addition to GeneratedMessage_reservedNames, which are names from
// the base GeneratedMessage class determined by reflection.
const _generatedMessageNames = const <String>[
// List of names used in the generated enum classes.
// This is in addition to ProtobufEnum_reservedNames, which are names from the
// base ProtobufEnum class determined by reflection.
const _protobufEnumNames = const <String>[