dev/tools/update_icons.dart - mirrors/flutter - Git at Google

 // 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.

 // Regenerates the material icons file.
 // See https://github.com/flutter/flutter/wiki/Updating-Material-Design-Fonts-&-Icons

 import 'dart:collection';
 import 'dart:convert' show LineSplitter;
 import 'dart:io';

 import 'package:args/args.dart';
 import 'package:meta/meta.dart';
 import 'package:path/path.dart' as path;

 const String _iconsPathOption = 'icons';
 const String _iconsTemplatePathOption = 'icons-template';
 const String _newCodepointsPathOption = 'new-codepoints';
 const String _oldCodepointsPathOption = 'old-codepoints';
 const String _fontFamilyOption = 'font-family';
 const String _enforceSafetyChecks = 'enforce-safety-checks';
 const String _dryRunOption = 'dry-run';

 const String _defaultIconsPath = 'packages/flutter/lib/src/material/icons.dart';
 const String _defaultNewCodepointsPath = 'codepoints';
 const String _defaultOldCodepointsPath = 'bin/cache/artifacts/material_fonts/codepoints';
 const String _defaultFontFamily = 'MaterialIcons';

 const String _beginGeneratedMark = '// BEGIN GENERATED ICONS';
 const String _endGeneratedMark = '// END GENERATED ICONS';
 const String _beginPlatformAdaptiveGeneratedMark = '// BEGIN GENERATED PLATFORM ADAPTIVE ICONS';
 const String _endPlatformAdaptiveGeneratedMark = '// END GENERATED PLATFORM ADAPTIVE ICONS';

 const Map<String, List<String>> _platformAdaptiveIdentifiers = <String, List<String>>{
   // Mapping of Flutter IDs to an Android/agnostic ID and an iOS ID.
   // Flutter IDs can be anything, but should be chosen to be agnostic.
   'arrow_back': <String>['arrow_back', 'arrow_back_ios'],
   'arrow_forward': <String>['arrow_forward', 'arrow_forward_ios'],
   'flip_camera': <String>['flip_camera_android', 'flip_camera_ios'],
   'more': <String>['more_vert', 'more_horiz'],
   'share': <String>['share', 'ios_share'],
 };

 // Rewrite certain Flutter IDs (numbers) using prefix matching.
 const Map<String, String> identifierPrefixRewrites = <String, String>{
   '1': 'one_',
   '2': 'two_',
   '3': 'three_',
   '4': 'four_',
   '5': 'five_',
   '6': 'six_',
   '7': 'seven_',
   '8': 'eight_',
   '9': 'nine_',
   '10': 'ten_',
   '11': 'eleven_',
   '12': 'twelve_',
   '13': 'thirteen_',
   '14': 'fourteen_',
   '15': 'fifteen_',
   '16': 'sixteen_',
   '17': 'seventeen_',
   '18': 'eighteen_',
   '19': 'nineteen_',
   '20': 'twenty_',
   '21': 'twenty_one_',
   '22': 'twenty_two_',
   '23': 'twenty_three_',
   '24': 'twenty_four_',
   '30': 'thirty_',
   '60': 'sixty_',
   '123': 'onetwothree',
   '360': 'threesixty',
   '2d': 'twod',
   '3d': 'threed',
   '3d_rotation': 'threed_rotation',
 };

 // Rewrite certain Flutter IDs (reserved keywords) using exact matching.
 const Map<String, String> identifierExactRewrites = <String, String>{
   'class': 'class_',
   'new': 'new_',
   'switch': 'switch_',
   'try': 'try_sms_star',
   'door_back': 'door_back_door',
   'door_front': 'door_front_door',
 };

 const Set<String> _iconsMirroredWhenRTL = <String>{
   // This list is obtained from:
   // http://google.github.io/material-design-icons/#icons-in-rtl
   'arrow_back',
   'arrow_back_ios',
   'arrow_forward',
   'arrow_forward_ios',
   'arrow_left',
   'arrow_right',
   'assignment',
   'assignment_return',
   'backspace',
   'battery_unknown',
   'call_made',
   'call_merge',
   'call_missed',
   'call_missed_outgoing',
   'call_received',
   'call_split',
   'chevron_left',
   'chevron_right',
   'chrome_reader_mode',
   'device_unknown',
   'dvr',
   'event_note',
   'featured_play_list',
   'featured_video',
   'first_page',
   'flight_land',
   'flight_takeoff',
   'format_indent_decrease',
   'format_indent_increase',
   'format_list_bulleted',
   'forward',
   'functions',
   'help',
   'help_outline',
   'input',
   'keyboard_backspace',
   'keyboard_tab',
   'label',
   'label_important',
   'label_outline',
   'last_page',
   'launch',
   'list',
   'live_help',
   'mobile_screen_share',
   'multiline_chart',
   'navigate_before',
   'navigate_next',
   'next_week',
   'note',
   'open_in_new',
   'playlist_add',
   'queue_music',
   'redo',
   'reply',
   'reply_all',
   'screen_share',
   'send',
   'short_text',
   'show_chart',
   'sort',
   'star_half',
   'subject',
   'trending_flat',
   'toc',
   'trending_down',
   'trending_up',
   'undo',
   'view_list',
   'view_quilt',
   'wrap_text',
 };

 void main(List<String> args) {
   // If we're run from the `tools` dir, set the cwd to the repo root.
   if (path.basename(Directory.current.path) == 'tools')
     Directory.current = Directory.current.parent.parent;

   final ArgResults argResults = _handleArguments(args);

   final File iconsFile = File(path.normalize(path.absolute(argResults[_iconsPathOption] as String)));
   if (!iconsFile.existsSync()) {
     stderr.writeln('Error: Icons file not found: ${iconsFile.path}');
     exit(1);
   }
   final File iconsTemplateFile = File(path.normalize(path.absolute(argResults[_iconsTemplatePathOption] as String)));
   if (!iconsTemplateFile.existsSync()) {
     stderr.writeln('Error: Icons template file not found: ${iconsTemplateFile.path}');
     exit(1);
   }
   final File newCodepointsFile = File(argResults[_newCodepointsPathOption] as String);
   if (!newCodepointsFile.existsSync()) {
     stderr.writeln('Error: New codepoints file not found: ${newCodepointsFile.path}');
     exit(1);
   }
   final File oldCodepointsFile = File(argResults[_oldCodepointsPathOption] as String);
   if (!oldCodepointsFile.existsSync()) {
     stderr.writeln('Error: Old codepoints file not found: ${oldCodepointsFile.path}');
     exit(1);
   }

   final String newCodepointsString = newCodepointsFile.readAsStringSync();
   final Map<String, String> newTokenPairMap = _stringToTokenPairMap(newCodepointsString);

   final String oldCodepointsString = oldCodepointsFile.readAsStringSync();
   final Map<String, String> oldTokenPairMap = _stringToTokenPairMap(oldCodepointsString);

   stderr.writeln('Performing safety checks');
   final bool isSuperset = testIsSuperset(newTokenPairMap, oldTokenPairMap);
   final bool isStable = testIsStable(newTokenPairMap, oldTokenPairMap);
   if ((!isSuperset || !isStable) && argResults[_enforceSafetyChecks] as bool) {
     exit(1);
   }
   final String iconsTemplateContents = iconsTemplateFile.readAsStringSync();

   stderr.writeln("Generating icons ${argResults[_dryRunOption] as bool ? '' : 'to ${iconsFile.path}'}");
   final String newIconsContents = _regenerateIconsFile(
     iconsTemplateContents,
     newTokenPairMap,
     argResults[_fontFamilyOption] as String,
     argResults[_enforceSafetyChecks] as bool,
   );

   if (argResults[_dryRunOption] as bool) {
     stdout.write(newIconsContents);
   } else {
     iconsFile.writeAsStringSync(newIconsContents);
     _regenerateCodepointsFile(oldCodepointsFile, newTokenPairMap);
   }
 }

 ArgResults _handleArguments(List<String> args) {
   final ArgParser argParser = ArgParser()
     ..addOption(_iconsPathOption,
         defaultsTo: _defaultIconsPath,
         help: 'Location of the material icons file')
     ..addOption(_iconsTemplatePathOption,
         defaultsTo: _defaultIconsPath,
         help:
             'Location of the material icons file template. Usually the same as --$_iconsPathOption')
     ..addOption(_newCodepointsPathOption,
         defaultsTo: _defaultNewCodepointsPath,
         help: 'Location of the new codepoints directory')
     ..addOption(_oldCodepointsPathOption,
         defaultsTo: _defaultOldCodepointsPath,
         help: 'Location of the existing codepoints directory')
     ..addOption(_fontFamilyOption,
         defaultsTo: _defaultFontFamily,
         help: 'The font family to use for the IconData constants')
     ..addFlag(_enforceSafetyChecks,
         defaultsTo: true,
         help: 'Whether to exit if safety checks fail (e.g. codepoints are missing or unstable')
     ..addFlag(_dryRunOption);
   argParser.addFlag('help', abbr: 'h', negatable: false, callback: (bool help) {
     if (help) {
       print(argParser.usage);
       exit(1);
     }
   });
   return argParser.parse(args);
 }

 Map<String, String> _stringToTokenPairMap(String codepointData) {
   final Iterable<String> cleanData = LineSplitter.split(codepointData)
       .map((String line) => line.trim())
       .where((String line) => line.isNotEmpty);

   final Map<String, String> pairs = <String, String>{};

   for (final String line in cleanData) {
     final List<String> tokens = line.split(' ');
     if (tokens.length != 2) {
       throw FormatException('Unexpected codepoint data: $line');
     }
     pairs.putIfAbsent(tokens[0], () => tokens[1]);
   }

   return pairs;
 }

 String _regenerateIconsFile(
     String templateFileContents,
     Map<String, String> tokenPairMap,
     String fontFamily,
     bool enforceSafetyChecks,
   ) {
   final List<Icon> newIcons = tokenPairMap.entries
       .map((MapEntry<String, String> entry) => Icon(entry, fontFamily))
       .toList();
   newIcons.sort((Icon a, Icon b) => a._compareTo(b));

   final StringBuffer buf = StringBuffer();
   bool generating = false;

   for (final String line in LineSplitter.split(templateFileContents)) {
     if (!generating) {
       buf.writeln(line);
     }

     // Generate for PlatformAdaptiveIcons
     if (line.contains(_beginPlatformAdaptiveGeneratedMark)) {
       generating = true;
       final List<String> platformAdaptiveDeclarations = <String>[];
       _platformAdaptiveIdentifiers.forEach((String flutterId, List<String> ids) {
         // Automatically finds and generates all icon declarations.
         for (final String style in <String>['', '_outlined', '_rounded', '_sharp']) {
           try {
             final Icon agnosticIcon = newIcons.firstWhere(
                 (Icon icon) => icon.id == '${ids[0]}$style',
                 orElse: () => throw ids[0]);
             final Icon iOSIcon = newIcons.firstWhere(
                 (Icon icon) => icon.id == '${ids[1]}$style',
                 orElse: () => throw ids[1]);
             platformAdaptiveDeclarations.add(Icon.platformAdaptiveDeclaration('$flutterId$style', agnosticIcon, iOSIcon),
             );
           } catch (e) {
             if (style == '') {
               // Throw an error for baseline icons.
               stderr.writeln("❌ Platform adaptive icon '$e' not found.");
               if (enforceSafetyChecks) {
                 stderr.writeln('Safety checks failed');
                 exit(1);
               }
             } else {
               // Ignore errors for styled icons since some don't exist.
             }
           }
         }
       });
       buf.write(platformAdaptiveDeclarations.join());
     } else if (line.contains(_endPlatformAdaptiveGeneratedMark)) {
       generating = false;
       buf.writeln(line);
     }

     // Generate for Icons
     if (line.contains(_beginGeneratedMark)) {
       generating = true;
       final String iconDeclarationsString = newIcons.map((Icon icon) => icon.fullDeclaration).join();
       buf.write(iconDeclarationsString);
     } else if (line.contains(_endGeneratedMark)) {
       generating = false;
       buf.writeln(line);
     }
   }
   return buf.toString();
 }

 @visibleForTesting
 bool testIsSuperset(Map<String, String> newCodepoints, Map<String, String> oldCodepoints) {
   final Set<String> newCodepointsSet = newCodepoints.keys.toSet();
   final Set<String> oldCodepointsSet = oldCodepoints.keys.toSet();

   final int diff = newCodepointsSet.length - oldCodepointsSet.length;
   if (diff > 0) {
     stderr.writeln('🆕 $diff new codepoints: ${newCodepointsSet.difference(oldCodepointsSet)}');
   }
   if (!newCodepointsSet.containsAll(oldCodepointsSet)) {
     stderr.writeln(
         '❌ new codepoints file does not contain all ${oldCodepointsSet.length} '
         'existing codepoints. Missing: ${oldCodepointsSet.difference(newCodepointsSet)}');
     return false;
   } else {
     stderr.writeln('✅ new codepoints file contains all ${oldCodepointsSet.length} existing codepoints');
   }
   return true;
 }

 @visibleForTesting
 bool testIsStable(Map<String, String> newCodepoints, Map<String, String> oldCodepoints) {
   final int oldCodepointsCount = oldCodepoints.length;
   final List<String> unstable = <String>[];

   oldCodepoints.forEach((String key, String value) {
     if (newCodepoints.containsKey(key)) {
       if (value != newCodepoints[key]) {
         unstable.add(key);
       }
     }
   });

   if (unstable.isNotEmpty) {
     stderr.writeln('❌ out of $oldCodepointsCount existing codepoints, ${unstable.length} were unstable: $unstable');
     return false;
   } else {
     stderr.writeln('✅ all existing $oldCodepointsCount codepoints are stable');
     return true;
   }
 }

 void _regenerateCodepointsFile(File oldCodepointsFile, Map<String, String> newTokenPairMap) {
   stderr.writeln('Regenerating old codepoints file ${oldCodepointsFile.path}');

   final StringBuffer buf = StringBuffer();
   final SplayTreeMap<String, String> sortedNewTokenPairMap = SplayTreeMap<String, String>.of(newTokenPairMap);
   sortedNewTokenPairMap.forEach((String key, String value) => buf.writeln('$key $value'));
   oldCodepointsFile.writeAsStringSync(buf.toString());
 }

 class Icon {
   // Parse tokenPair (e.g. {"6_ft_apart_outlined": "e004"}).
   Icon(MapEntry<String, String> tokenPair, this.fontFamily) {
     id = tokenPair.key;
     hexCodepoint = tokenPair.value;

     // Determine family and htmlSuffix.
     if (id.endsWith('_gm_outlined')) {
       family = 'GM';
       htmlSuffix = '-outlined';
     } else if (id.endsWith('_gm_filled')) {
       family = 'GM';
       htmlSuffix = '-filled';
     } else if (id.endsWith('_monoline_outlined')) {
       family = 'Monoline';
       htmlSuffix = '-outlined';
     } else if (id.endsWith('_monoline_filled')) {
       family = 'Monoline';
       htmlSuffix = '-filled';
     } else {
       family = 'material';
       if (id.endsWith('_baseline')) {
         id = _removeLast(id, '_baseline');
         htmlSuffix = '';
       } else if (id.endsWith('_outlined')) {
         htmlSuffix = '-outlined';
       } else if (id.endsWith('_rounded')) {
         htmlSuffix = '-round';
       } else if (id.endsWith('_sharp')) {
         htmlSuffix = '-sharp';
       }
     }

     shortId = _generateShortId(id);
     flutterId = generateFlutterId(id);
   }

   static const List<String> _idSuffixes = <String>[
     '_gm_outlined',
     '_gm_filled',
     '_monoline_outlined',
     '_monoline_filled',
     '_outlined',
     '_rounded',
     '_sharp'
   ];

   late String id; // e.g. 5g, 5g_outlined, 5g_rounded, 5g_sharp
   late String shortId; // e.g. 5g
   late String flutterId; // e.g. five_g, five_g_outlined, five_g_rounded, five_g_sharp
   late String family; // e.g. material
   late String hexCodepoint; // e.g. e547
   late String htmlSuffix = ''; // The suffix for the 'material-icons' HTML class.
   String fontFamily; // The IconData font family.

   String get name => shortId.replaceAll('_', ' ').trim();

   String get style => htmlSuffix == '' ? '' : ' (${htmlSuffix.replaceFirst('-', '')})';

   String get dartDoc =>
       '<i class="material-icons$htmlSuffix md-36">$shortId</i> &#x2014; $family icon named "$name"$style';

   String get mirroredInRTL => _iconsMirroredWhenRTL.contains(shortId)
       ? ', matchTextDirection: true'
       : '';

   String get declaration =>
       "static const IconData $flutterId = IconData(0x$hexCodepoint, fontFamily: '$fontFamily'$mirroredInRTL);";

   String get fullDeclaration => '''

   /// $dartDoc.
   $declaration
 ''';

   static String platformAdaptiveDeclaration(String fullFlutterId, Icon agnosticIcon, Icon iOSIcon) => '''

   /// Platform-adaptive icon for ${agnosticIcon.dartDoc} and ${iOSIcon.dartDoc}.;
   IconData get $fullFlutterId => !_isCupertino() ? Icons.${agnosticIcon.flutterId} : Icons.${iOSIcon.flutterId};
 ''';

   @override
   String toString() => id;

   /// Analogous to [String.compareTo]
   int _compareTo(Icon b) {
     if (shortId == b.shortId) {
       // Sort a regular icon before its variants.
       return id.length - b.id.length;
     }
     return shortId.compareTo(b.shortId);
   }

   static String _removeLast(String string, String toReplace) {
     return string.replaceAll(RegExp('$toReplace\$'), '');
   }

   static String _generateShortId(String id) {
     String shortId = id;
     for (final String styleSuffix in _idSuffixes) {
       shortId = _removeLast(shortId, styleSuffix);
       if (shortId != id) {
         break;
       }
     }
     return shortId;
   }

   /// Given some icon's raw id, returns a valid Dart icon identifier
   static String generateFlutterId(String id) {
     String flutterId = id;
     // Exact identifier rewrites.
     for (final MapEntry<String, String> rewritePair in identifierExactRewrites.entries) {
       final String shortId = Icon._generateShortId(id);
       if (shortId == rewritePair.key) {
         flutterId = id.replaceFirst(
           rewritePair.key,
           identifierExactRewrites[rewritePair.key]!,
         );
       }
     }
     // Prefix identifier rewrites.
     for (final MapEntry<String, String> rewritePair in identifierPrefixRewrites.entries) {
       if (id.startsWith(rewritePair.key)) {
         flutterId = id.replaceFirst(
           rewritePair.key,
           identifierPrefixRewrites[rewritePair.key]!,
         );
       }
     }

     // Prevent double underscores.
     flutterId = flutterId.replaceAll('__', '_');

     return flutterId;
   }
 }
	// 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.

	// Regenerates the material icons file.
	// See https://github.com/flutter/flutter/wiki/Updating-Material-Design-Fonts-&-Icons

	import 'dart:collection';
	import 'dart:convert' show LineSplitter;
	import 'dart:io';

	import 'package:args/args.dart';
	import 'package:meta/meta.dart';
	import 'package:path/path.dart' as path;

	const String _iconsPathOption = 'icons';
	const String _iconsTemplatePathOption = 'icons-template';
	const String _newCodepointsPathOption = 'new-codepoints';
	const String _oldCodepointsPathOption = 'old-codepoints';
	const String _fontFamilyOption = 'font-family';
	const String _enforceSafetyChecks = 'enforce-safety-checks';
	const String _dryRunOption = 'dry-run';

	const String _defaultIconsPath = 'packages/flutter/lib/src/material/icons.dart';
	const String _defaultNewCodepointsPath = 'codepoints';
	const String _defaultOldCodepointsPath = 'bin/cache/artifacts/material_fonts/codepoints';
	const String _defaultFontFamily = 'MaterialIcons';

	const String _beginGeneratedMark = '// BEGIN GENERATED ICONS';
	const String _endGeneratedMark = '// END GENERATED ICONS';
	const String _beginPlatformAdaptiveGeneratedMark = '// BEGIN GENERATED PLATFORM ADAPTIVE ICONS';
	const String _endPlatformAdaptiveGeneratedMark = '// END GENERATED PLATFORM ADAPTIVE ICONS';

	const Map<String, List<String>> _platformAdaptiveIdentifiers = <String, List<String>>{
	// Mapping of Flutter IDs to an Android/agnostic ID and an iOS ID.
	// Flutter IDs can be anything, but should be chosen to be agnostic.
	'arrow_back': <String>['arrow_back', 'arrow_back_ios'],
	'arrow_forward': <String>['arrow_forward', 'arrow_forward_ios'],
	'flip_camera': <String>['flip_camera_android', 'flip_camera_ios'],
	'more': <String>['more_vert', 'more_horiz'],
	'share': <String>['share', 'ios_share'],
	};

	// Rewrite certain Flutter IDs (numbers) using prefix matching.
	const Map<String, String> identifierPrefixRewrites = <String, String>{
	'1': 'one_',
	'2': 'two_',
	'3': 'three_',
	'4': 'four_',
	'5': 'five_',
	'6': 'six_',
	'7': 'seven_',
	'8': 'eight_',
	'9': 'nine_',
	'10': 'ten_',
	'11': 'eleven_',
	'12': 'twelve_',
	'13': 'thirteen_',
	'14': 'fourteen_',
	'15': 'fifteen_',
	'16': 'sixteen_',
	'17': 'seventeen_',
	'18': 'eighteen_',
	'19': 'nineteen_',
	'20': 'twenty_',
	'21': 'twenty_one_',
	'22': 'twenty_two_',
	'23': 'twenty_three_',
	'24': 'twenty_four_',
	'30': 'thirty_',
	'60': 'sixty_',
	'123': 'onetwothree',
	'360': 'threesixty',
	'2d': 'twod',
	'3d': 'threed',
	'3d_rotation': 'threed_rotation',
	};

	// Rewrite certain Flutter IDs (reserved keywords) using exact matching.
	const Map<String, String> identifierExactRewrites = <String, String>{
	'class': 'class_',
	'new': 'new_',
	'switch': 'switch_',
	'try': 'try_sms_star',
	'door_back': 'door_back_door',
	'door_front': 'door_front_door',
	};

	const Set<String> _iconsMirroredWhenRTL = <String>{
	// This list is obtained from:
	// http://google.github.io/material-design-icons/#icons-in-rtl
	'arrow_back',
	'arrow_back_ios',
	'arrow_forward',
	'arrow_forward_ios',
	'arrow_left',
	'arrow_right',
	'assignment',
	'assignment_return',
	'backspace',
	'battery_unknown',
	'call_made',
	'call_merge',
	'call_missed',
	'call_missed_outgoing',
	'call_received',
	'call_split',
	'chevron_left',
	'chevron_right',
	'chrome_reader_mode',
	'device_unknown',
	'dvr',
	'event_note',
	'featured_play_list',
	'featured_video',
	'first_page',
	'flight_land',
	'flight_takeoff',
	'format_indent_decrease',
	'format_indent_increase',
	'format_list_bulleted',
	'forward',
	'functions',
	'help',
	'help_outline',
	'input',
	'keyboard_backspace',
	'keyboard_tab',
	'label',
	'label_important',
	'label_outline',
	'last_page',
	'launch',
	'list',
	'live_help',
	'mobile_screen_share',
	'multiline_chart',
	'navigate_before',
	'navigate_next',
	'next_week',
	'note',
	'open_in_new',
	'playlist_add',
	'queue_music',
	'redo',
	'reply',
	'reply_all',
	'screen_share',
	'send',
	'short_text',
	'show_chart',
	'sort',
	'star_half',
	'subject',
	'trending_flat',
	'toc',
	'trending_down',
	'trending_up',
	'undo',
	'view_list',
	'view_quilt',
	'wrap_text',
	};

	void main(List<String> args) {
	// If we're run from the `tools` dir, set the cwd to the repo root.
	if (path.basename(Directory.current.path) == 'tools')
	Directory.current = Directory.current.parent.parent;

	final ArgResults argResults = _handleArguments(args);

	final File iconsFile = File(path.normalize(path.absolute(argResults[_iconsPathOption] as String)));
	if (!iconsFile.existsSync()) {
	stderr.writeln('Error: Icons file not found: ${iconsFile.path}');
	exit(1);
	}
	final File iconsTemplateFile = File(path.normalize(path.absolute(argResults[_iconsTemplatePathOption] as String)));
	if (!iconsTemplateFile.existsSync()) {
	stderr.writeln('Error: Icons template file not found: ${iconsTemplateFile.path}');
	exit(1);
	}
	final File newCodepointsFile = File(argResults[_newCodepointsPathOption] as String);
	if (!newCodepointsFile.existsSync()) {
	stderr.writeln('Error: New codepoints file not found: ${newCodepointsFile.path}');
	exit(1);
	}
	final File oldCodepointsFile = File(argResults[_oldCodepointsPathOption] as String);
	if (!oldCodepointsFile.existsSync()) {
	stderr.writeln('Error: Old codepoints file not found: ${oldCodepointsFile.path}');
	exit(1);
	}

	final String newCodepointsString = newCodepointsFile.readAsStringSync();
	final Map<String, String> newTokenPairMap = _stringToTokenPairMap(newCodepointsString);

	final String oldCodepointsString = oldCodepointsFile.readAsStringSync();
	final Map<String, String> oldTokenPairMap = _stringToTokenPairMap(oldCodepointsString);

	stderr.writeln('Performing safety checks');
	final bool isSuperset = testIsSuperset(newTokenPairMap, oldTokenPairMap);
	final bool isStable = testIsStable(newTokenPairMap, oldTokenPairMap);
	if ((!isSuperset \|\| !isStable) && argResults[_enforceSafetyChecks] as bool) {
	exit(1);
	}
	final String iconsTemplateContents = iconsTemplateFile.readAsStringSync();

	stderr.writeln("Generating icons ${argResults[_dryRunOption] as bool ? '' : 'to ${iconsFile.path}'}");
	final String newIconsContents = _regenerateIconsFile(
	iconsTemplateContents,
	newTokenPairMap,
	argResults[_fontFamilyOption] as String,
	argResults[_enforceSafetyChecks] as bool,
	);

	if (argResults[_dryRunOption] as bool) {
	stdout.write(newIconsContents);
	} else {
	iconsFile.writeAsStringSync(newIconsContents);
	_regenerateCodepointsFile(oldCodepointsFile, newTokenPairMap);
	}
	}

	ArgResults _handleArguments(List<String> args) {
	final ArgParser argParser = ArgParser()
	..addOption(_iconsPathOption,
	defaultsTo: _defaultIconsPath,
	help: 'Location of the material icons file')
	..addOption(_iconsTemplatePathOption,
	defaultsTo: _defaultIconsPath,
	help:
	'Location of the material icons file template. Usually the same as --$_iconsPathOption')
	..addOption(_newCodepointsPathOption,
	defaultsTo: _defaultNewCodepointsPath,
	help: 'Location of the new codepoints directory')
	..addOption(_oldCodepointsPathOption,
	defaultsTo: _defaultOldCodepointsPath,
	help: 'Location of the existing codepoints directory')
	..addOption(_fontFamilyOption,
	defaultsTo: _defaultFontFamily,
	help: 'The font family to use for the IconData constants')
	..addFlag(_enforceSafetyChecks,
	defaultsTo: true,
	help: 'Whether to exit if safety checks fail (e.g. codepoints are missing or unstable')
	..addFlag(_dryRunOption);
	argParser.addFlag('help', abbr: 'h', negatable: false, callback: (bool help) {
	if (help) {
	print(argParser.usage);
	exit(1);
	}
	});
	return argParser.parse(args);
	}

	Map<String, String> _stringToTokenPairMap(String codepointData) {
	final Iterable<String> cleanData = LineSplitter.split(codepointData)
	.map((String line) => line.trim())
	.where((String line) => line.isNotEmpty);

	final Map<String, String> pairs = <String, String>{};

	for (final String line in cleanData) {
	final List<String> tokens = line.split(' ');
	if (tokens.length != 2) {
	throw FormatException('Unexpected codepoint data: $line');
	}
	pairs.putIfAbsent(tokens[0], () => tokens[1]);
	}

	return pairs;
	}

	String _regenerateIconsFile(
	String templateFileContents,
	Map<String, String> tokenPairMap,
	String fontFamily,
	bool enforceSafetyChecks,
	) {
	final List<Icon> newIcons = tokenPairMap.entries
	.map((MapEntry<String, String> entry) => Icon(entry, fontFamily))
	.toList();
	newIcons.sort((Icon a, Icon b) => a._compareTo(b));

	final StringBuffer buf = StringBuffer();
	bool generating = false;

	for (final String line in LineSplitter.split(templateFileContents)) {
	if (!generating) {
	buf.writeln(line);
	}

	// Generate for PlatformAdaptiveIcons
	if (line.contains(_beginPlatformAdaptiveGeneratedMark)) {
	generating = true;
	final List<String> platformAdaptiveDeclarations = <String>[];
	_platformAdaptiveIdentifiers.forEach((String flutterId, List<String> ids) {
	// Automatically finds and generates all icon declarations.
	for (final String style in <String>['', '_outlined', '_rounded', '_sharp']) {
	try {
	final Icon agnosticIcon = newIcons.firstWhere(
	(Icon icon) => icon.id == '${ids[0]}$style',
	orElse: () => throw ids[0]);
	final Icon iOSIcon = newIcons.firstWhere(
	(Icon icon) => icon.id == '${ids[1]}$style',
	orElse: () => throw ids[1]);
	platformAdaptiveDeclarations.add(Icon.platformAdaptiveDeclaration('$flutterId$style', agnosticIcon, iOSIcon),
	);
	} catch (e) {
	if (style == '') {
	// Throw an error for baseline icons.
	stderr.writeln("❌ Platform adaptive icon '$e' not found.");
	if (enforceSafetyChecks) {
	stderr.writeln('Safety checks failed');
	exit(1);
	}
	} else {
	// Ignore errors for styled icons since some don't exist.
	}
	}
	}
	});
	buf.write(platformAdaptiveDeclarations.join());
	} else if (line.contains(_endPlatformAdaptiveGeneratedMark)) {
	generating = false;
	buf.writeln(line);
	}

	// Generate for Icons
	if (line.contains(_beginGeneratedMark)) {
	generating = true;
	final String iconDeclarationsString = newIcons.map((Icon icon) => icon.fullDeclaration).join();
	buf.write(iconDeclarationsString);
	} else if (line.contains(_endGeneratedMark)) {
	generating = false;
	buf.writeln(line);
	}
	}
	return buf.toString();
	}

	@visibleForTesting
	bool testIsSuperset(Map<String, String> newCodepoints, Map<String, String> oldCodepoints) {
	final Set<String> newCodepointsSet = newCodepoints.keys.toSet();
	final Set<String> oldCodepointsSet = oldCodepoints.keys.toSet();

	final int diff = newCodepointsSet.length - oldCodepointsSet.length;
	if (diff > 0) {
	stderr.writeln('🆕 $diff new codepoints: ${newCodepointsSet.difference(oldCodepointsSet)}');
	}
	if (!newCodepointsSet.containsAll(oldCodepointsSet)) {
	stderr.writeln(
	'❌ new codepoints file does not contain all ${oldCodepointsSet.length} '
	'existing codepoints. Missing: ${oldCodepointsSet.difference(newCodepointsSet)}');
	return false;
	} else {
	stderr.writeln('✅ new codepoints file contains all ${oldCodepointsSet.length} existing codepoints');
	}
	return true;
	}

	@visibleForTesting
	bool testIsStable(Map<String, String> newCodepoints, Map<String, String> oldCodepoints) {
	final int oldCodepointsCount = oldCodepoints.length;
	final List<String> unstable = <String>[];

	oldCodepoints.forEach((String key, String value) {
	if (newCodepoints.containsKey(key)) {
	if (value != newCodepoints[key]) {
	unstable.add(key);
	}
	}
	});

	if (unstable.isNotEmpty) {
	stderr.writeln('❌ out of $oldCodepointsCount existing codepoints, ${unstable.length} were unstable: $unstable');
	return false;
	} else {
	stderr.writeln('✅ all existing $oldCodepointsCount codepoints are stable');
	return true;
	}
	}

	void _regenerateCodepointsFile(File oldCodepointsFile, Map<String, String> newTokenPairMap) {
	stderr.writeln('Regenerating old codepoints file ${oldCodepointsFile.path}');

	final StringBuffer buf = StringBuffer();
	final SplayTreeMap<String, String> sortedNewTokenPairMap = SplayTreeMap<String, String>.of(newTokenPairMap);
	sortedNewTokenPairMap.forEach((String key, String value) => buf.writeln('$key $value'));
	oldCodepointsFile.writeAsStringSync(buf.toString());
	}

	class Icon {
	// Parse tokenPair (e.g. {"6_ft_apart_outlined": "e004"}).
	Icon(MapEntry<String, String> tokenPair, this.fontFamily) {
	id = tokenPair.key;
	hexCodepoint = tokenPair.value;

	// Determine family and htmlSuffix.
	if (id.endsWith('_gm_outlined')) {
	family = 'GM';
	htmlSuffix = '-outlined';
	} else if (id.endsWith('_gm_filled')) {
	family = 'GM';
	htmlSuffix = '-filled';
	} else if (id.endsWith('_monoline_outlined')) {
	family = 'Monoline';
	htmlSuffix = '-outlined';
	} else if (id.endsWith('_monoline_filled')) {
	family = 'Monoline';
	htmlSuffix = '-filled';
	} else {
	family = 'material';
	if (id.endsWith('_baseline')) {
	id = _removeLast(id, '_baseline');
	htmlSuffix = '';
	} else if (id.endsWith('_outlined')) {
	htmlSuffix = '-outlined';
	} else if (id.endsWith('_rounded')) {
	htmlSuffix = '-round';
	} else if (id.endsWith('_sharp')) {
	htmlSuffix = '-sharp';
	}
	}

	shortId = _generateShortId(id);
	flutterId = generateFlutterId(id);
	}

	static const List<String> _idSuffixes = <String>[
	'_gm_outlined',
	'_gm_filled',
	'_monoline_outlined',
	'_monoline_filled',
	'_outlined',
	'_rounded',
	'_sharp'
	];

	late String id; // e.g. 5g, 5g_outlined, 5g_rounded, 5g_sharp
	late String shortId; // e.g. 5g
	late String flutterId; // e.g. five_g, five_g_outlined, five_g_rounded, five_g_sharp
	late String family; // e.g. material
	late String hexCodepoint; // e.g. e547
	late String htmlSuffix = ''; // The suffix for the 'material-icons' HTML class.
	String fontFamily; // The IconData font family.

	String get name => shortId.replaceAll('_', ' ').trim();

	String get style => htmlSuffix == '' ? '' : ' (${htmlSuffix.replaceFirst('-', '')})';

	String get dartDoc =>
	'<i class="material-icons$htmlSuffix md-36">$shortId</i> — $family icon named "$name"$style';

	String get mirroredInRTL => _iconsMirroredWhenRTL.contains(shortId)
	? ', matchTextDirection: true'
	: '';

	String get declaration =>
	"static const IconData $flutterId = IconData(0x$hexCodepoint, fontFamily: '$fontFamily'$mirroredInRTL);";

	String get fullDeclaration => '''

	/// $dartDoc.
	$declaration
	''';

	static String platformAdaptiveDeclaration(String fullFlutterId, Icon agnosticIcon, Icon iOSIcon) => '''

	/// Platform-adaptive icon for ${agnosticIcon.dartDoc} and ${iOSIcon.dartDoc}.;
	IconData get $fullFlutterId => !_isCupertino() ? Icons.${agnosticIcon.flutterId} : Icons.${iOSIcon.flutterId};
	''';

	@override
	String toString() => id;

	/// Analogous to [String.compareTo]
	int _compareTo(Icon b) {
	if (shortId == b.shortId) {
	// Sort a regular icon before its variants.
	return id.length - b.id.length;
	}
	return shortId.compareTo(b.shortId);
	}

	static String _removeLast(String string, String toReplace) {
	return string.replaceAll(RegExp('$toReplace\$'), '');
	}

	static String _generateShortId(String id) {
	String shortId = id;
	for (final String styleSuffix in _idSuffixes) {
	shortId = _removeLast(shortId, styleSuffix);
	if (shortId != id) {
	break;
	}
	}
	return shortId;
	}

	/// Given some icon's raw id, returns a valid Dart icon identifier
	static String generateFlutterId(String id) {
	String flutterId = id;
	// Exact identifier rewrites.
	for (final MapEntry<String, String> rewritePair in identifierExactRewrites.entries) {
	final String shortId = Icon._generateShortId(id);
	if (shortId == rewritePair.key) {
	flutterId = id.replaceFirst(
	rewritePair.key,
	identifierExactRewrites[rewritePair.key]!,
	);
	}
	}
	// Prefix identifier rewrites.
	for (final MapEntry<String, String> rewritePair in identifierPrefixRewrites.entries) {
	if (id.startsWith(rewritePair.key)) {
	flutterId = id.replaceFirst(
	rewritePair.key,
	identifierPrefixRewrites[rewritePair.key]!,
	);
	}
	}

	// Prevent double underscores.
	flutterId = flutterId.replaceAll('__', '_');

	return flutterId;
	}
	}