blob: 3ceb2be33f3b4217b470f4bbb533fad50c783436 [file] [log] [blame]
// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'dart:io';
abstract class TokenTemplate {
const TokenTemplate(this.blockName, this.fileName, this.tokens, {
this.colorSchemePrefix = 'Theme.of(context).colorScheme.',
this.textThemePrefix = 'Theme.of(context).textTheme.'
/// Name of the code block that this template will generate.
/// Used to identify an existing block when updating it.
final String blockName;
/// Name of the file that will be updated with the generated code.
final String fileName;
/// Map of token data extracted from the Material Design token database.
final Map<String, dynamic> tokens;
/// Optional prefix prepended to color definitions.
/// Defaults to 'Theme.of(context).colorScheme.'
final String colorSchemePrefix;
/// Optional prefix prepended to text style definitians.
/// Defaults to 'Theme.of(context).textTheme.'
final String textThemePrefix;
static const String beginGeneratedComment = '''
static const String headerComment = '''
// Do not edit by hand. The code between the "BEGIN GENERATED" and
// "END GENERATED" comments are generated from data in the Material
// Design token database by the script:
// dev/tools/gen_defaults/bin/gen_defaults.dart.
static const String endGeneratedComment = '''
/// Replace or append the contents of the file with the text from [generate].
/// If the file already contains a generated text block matching the
/// [blockName], it will be replaced by the [generate] output. Otherwise
/// the content will just be appended to the end of the file.
Future<void> updateFile() async {
final String contents = File(fileName).readAsStringSync();
final String beginComment = '$beginGeneratedComment - $blockName\n';
final String endComment = '$endGeneratedComment - $blockName\n';
final int beginPreviousBlock = contents.indexOf(beginComment);
final int endPreviousBlock = contents.indexOf(endComment);
late String contentBeforeBlock;
late String contentAfterBlock;
if (beginPreviousBlock != -1) {
if (endPreviousBlock < beginPreviousBlock) {
print('Unable to find block named $blockName in $fileName, skipping code generation.');
// Found a valid block matching the name, so record the content before and after.
contentBeforeBlock = contents.substring(0, beginPreviousBlock);
contentAfterBlock = contents.substring(endPreviousBlock + endComment.length);
} else {
// Just append to the bottom.
contentBeforeBlock = contents;
contentAfterBlock = '';
final StringBuffer buffer = StringBuffer(contentBeforeBlock);
buffer.write('// Token database version: ${tokens['version']}\n\n');
/// Provide the generated content for the template.
/// This abstract method needs to be implemented by subclasses
/// to provide the content that [updateFile] will append to the
/// bottom of the file.
String generate();
/// Generate a [ColorScheme] color name for the given token.
/// If there is a value for the given token, this will return
/// the value prepended with [colorSchemePrefix].
/// Otherwise it will return [defaultValue].
/// See also:
/// * [componentColor], that provides support for an optional opacity.
String color(String colorToken, [String defaultValue = 'null']) {
return tokens.containsKey(colorToken)
? '$colorSchemePrefix${tokens[colorToken]}'
: defaultValue;
/// Generate a [ColorScheme] color name for the given token or a transparent
/// color if there is no value for the token.
/// If there is a value for the given token, this will return
/// the value prepended with [colorSchemePrefix].
/// Otherwise it will return 'Colors.transparent'.
/// See also:
/// * [componentColor], that provides support for an optional opacity.
String? colorOrTransparent(String token) => color(token, 'Colors.transparent');
/// Generate a [ColorScheme] color name for the given component's color
/// with opacity if available.
/// If there is a value for the given component's color, this will return
/// the value prepended with [colorSchemePrefix]. If there is also
/// an opacity specified for the component, then the returned value
/// will include this opacity calculation.
/// If there is no value for the component's color, 'null' will be returned.
/// See also:
/// * [color], that provides support for looking up a raw color token.
String componentColor(String componentToken) {
final String colorToken = '$componentToken.color';
if (!tokens.containsKey(colorToken)) {
return 'null';
String value = color(colorToken);
final String opacityToken = '$componentToken.opacity';
if (tokens.containsKey(opacityToken)) {
value += '.withOpacity(${opacity(opacityToken)})';
return value;
/// Generate the opacity value for the given token.
String? opacity(String token) {
final dynamic value = tokens[token];
if (value == null) {
return null;
if (value is double) {
return value.toString();
return tokens[value].toString();
/// Generate an elevation value for the given component token.
String elevation(String componentToken) {
return tokens[tokens['$componentToken.elevation']!]!.toString();
/// Generate a shape constant for the given component token.
/// Currently supports family:
/// - "SHAPE_FAMILY_ROUNDED_CORNERS" which maps to [RoundedRectangleBorder].
/// - "SHAPE_FAMILY_CIRCULAR" which maps to a [StadiumBorder].
String shape(String componentToken, [String prefix = 'const ']) {
final Map<String, dynamic> shape = tokens[tokens['$componentToken.shape']!]! as Map<String, dynamic>;
switch (shape['family']) {
final double topLeft = shape['topLeft'] as double;
final double topRight = shape['topRight'] as double;
final double bottomLeft = shape['bottomLeft'] as double;
final double bottomRight = shape['bottomRight'] as double;
if (topLeft == topRight && topLeft == bottomLeft && topLeft == bottomRight) {
return '${prefix}RoundedRectangleBorder(borderRadius: BorderRadius.all(Radius.circular($topLeft)))';
return '${prefix}RoundedRectangleBorder(borderRadius: '
'topLeft: Radius.circular(${shape['topLeft']}), '
'topRight: Radius.circular(${shape['topRight']}), '
'bottomLeft: Radius.circular(${shape['bottomLeft']}), '
'bottomRight: Radius.circular(${shape['bottomRight']})))';
return '${prefix}StadiumBorder()';
print('Unsupported shape family type: ${shape['family']} for $componentToken');
return '';
/// Generate a [BorderSide] for the given component.
String border(String componentToken) {
if (!tokens.containsKey('$componentToken.color')) {
return 'null';
final String borderColor = componentColor(componentToken);
final double width = (tokens['$componentToken.width'] ?? 1.0) as double;
return 'BorderSide(color: $borderColor${width != 1.0 ? ", width: $width" : ""})';
/// Generate a [TextTheme] text style name for the given component token.
String textStyle(String componentToken) {
return '$textThemePrefix${tokens["$componentToken.text-style"]}';