bin/format.dart

// Copyright (c) 2015, 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 'dart:convert';
import 'dart:io';

import 'package:args/args.dart';
import 'package:dart_style/src/dart_formatter.dart';
import 'package:dart_style/src/exceptions.dart';
import 'package:dart_style/src/formatter_options.dart';
import 'package:dart_style/src/io.dart';
import 'package:dart_style/src/source_code.dart';
import 'package:dart_style/src/style_fix.dart';

// Note: The following line of code is modified by tool/grind.dart.
const version = '1.3.3';

void main(List<String> args) {
  var parser = ArgParser(allowTrailingOptions: true);

  var verbose = args.contains('-v') || args.contains('--verbose');
  var hide = !verbose;

  parser.addSeparator('Common options:');
  parser.addFlag('help',
      abbr: 'h',
      negatable: false,
      help:
          'Shows this usage information.  Add --verbose to show hidden options.');
  parser.addFlag('version',
      negatable: false, help: 'Shows version information.');
  parser.addFlag('verbose',
      abbr: 'v', negatable: false, help: 'Verbose output.');
  parser.addOption('line-length',
      abbr: 'l', help: 'Wrap lines longer than this.', defaultsTo: '80');
  parser.addFlag('overwrite',
      abbr: 'w',
      negatable: false,
      help: 'Overwrite input files with formatted output.');
  parser.addFlag('dry-run',
      abbr: 'n',
      negatable: false,
      help: 'Show which files would be modified but make no changes.');

  parser.addSeparator('Non-whitespace fixes (off by default):');
  parser.addFlag('fix', negatable: false, help: 'Apply all style fixes.');

  for (var fix in StyleFix.all) {
    // TODO(rnystrom): Allow negating this if used in concert with "--fix"?
    parser.addFlag('fix-${fix.name}', negatable: false, help: fix.description);
  }

  if (verbose) {
    parser.addSeparator('Other options:');
  }
  parser.addOption('indent',
      abbr: 'i',
      help: 'Spaces of leading indentation.',
      defaultsTo: '0',
      hide: hide);
  parser.addFlag('machine',
      abbr: 'm',
      negatable: false,
      help: 'Produce machine-readable JSON output.',
      hide: hide);
  parser.addFlag('set-exit-if-changed',
      negatable: false,
      help: 'Return exit code 1 if there are any formatting changes.',
      hide: hide);
  parser.addFlag('follow-links',
      negatable: false,
      help: 'Follow links to files and directories.\n'
          'If unset, links will be ignored.',
      hide: hide);
  parser.addOption('preserve',
      help: 'Selection to preserve, formatted as "start:length".', hide: hide);
  parser.addOption('stdin-name',
      help: 'The path name to show when an error occurs in source read from '
          'stdin.',
      defaultsTo: '<stdin>',
      hide: hide);

  parser.addFlag('profile', negatable: false, hide: true);
  parser.addFlag('transform', abbr: 't', negatable: false, hide: true);

  ArgResults argResults;
  try {
    argResults = parser.parse(args);
  } on FormatException catch (err) {
    usageError(parser, err.message);
  }

  if (argResults['help']) {
    printUsage(parser);
    return;
  }

  if (argResults['version']) {
    print(version);
    return;
  }

  // Can only preserve a selection when parsing from stdin.
  List<int> selection;
  if (argResults['preserve'] != null && argResults.rest.isNotEmpty) {
    usageError(parser, 'Can only use --preserve when reading from stdin.');
  }

  try {
    selection = parseSelection(argResults['preserve']);
  } on FormatException catch (_) {
    usageError(
        parser,
        '--preserve must be a colon-separated pair of integers, was '
        '"${argResults['preserve']}".');
  }

  if (argResults['dry-run'] && argResults['overwrite']) {
    usageError(
        parser, 'Cannot use --dry-run and --overwrite at the same time.');
  }

  void checkForReporterCollision(String chosen, String other) {
    if (!argResults[other]) return;

    usageError(parser, 'Cannot use --$chosen and --$other at the same time.');
  }

  var reporter = OutputReporter.print;
  if (argResults['dry-run']) {
    checkForReporterCollision('dry-run', 'overwrite');
    checkForReporterCollision('dry-run', 'machine');

    reporter = OutputReporter.dryRun;
  } else if (argResults['overwrite']) {
    checkForReporterCollision('overwrite', 'machine');

    if (argResults.rest.isEmpty) {
      usageError(parser,
          'Cannot use --overwrite without providing any paths to format.');
    }

    reporter = OutputReporter.overwrite;
  } else if (argResults['machine']) {
    reporter = OutputReporter.printJson;
  }

  if (argResults['profile']) {
    reporter = ProfileReporter(reporter);
  }

  if (argResults['set-exit-if-changed']) {
    reporter = SetExitReporter(reporter);
  }

  int pageWidth;
  try {
    pageWidth = int.parse(argResults['line-length']);
  } on FormatException catch (_) {
    usageError(
        parser,
        '--line-length must be an integer, was '
        '"${argResults['line-length']}".');
  }

  int indent;
  try {
    indent = int.parse(argResults['indent']);
    if (indent < 0 || indent.toInt() != indent) throw FormatException();
  } on FormatException catch (_) {
    usageError(
        parser,
        '--indent must be a non-negative integer, was '
        '"${argResults['indent']}".');
  }

  var followLinks = argResults['follow-links'];

  var fixes = <StyleFix>[];
  if (argResults['fix']) fixes.addAll(StyleFix.all);
  for (var fix in StyleFix.all) {
    if (argResults['fix-${fix.name}']) {
      if (argResults['fix']) {
        usageError(parser, '--fix-${fix.name} is redundant with --fix.');
      }

      fixes.add(fix);
    }
  }

  if (argResults.wasParsed('stdin-name') && argResults.rest.isNotEmpty) {
    usageError(parser, 'Cannot pass --stdin-name when not reading from stdin.');
  }

  var options = FormatterOptions(reporter,
      indent: indent,
      pageWidth: pageWidth,
      followLinks: followLinks,
      fixes: fixes);

  if (argResults.rest.isEmpty) {
    formatStdin(options, selection, argResults['stdin-name'] as String);
  } else {
    formatPaths(options, argResults.rest);
  }

  if (argResults['profile']) {
    (reporter as ProfileReporter).showProfile();
  }
}

List<int> parseSelection(String selection) {
  if (selection == null) return null;

  var coordinates = selection.split(':');
  if (coordinates.length != 2) {
    throw FormatException(
        'Selection should be a colon-separated pair of integers, "123:45".');
  }

  return coordinates.map((coord) => coord.trim()).map(int.parse).toList();
}

/// Reads input from stdin until it's closed, and the formats it.
void formatStdin(FormatterOptions options, List<int> selection, String name) {
  var selectionStart = 0;
  var selectionLength = 0;

  if (selection != null) {
    selectionStart = selection[0];
    selectionLength = selection[1];
  }

  var input = StringBuffer();
  stdin.transform(Utf8Decoder()).listen(input.write, onDone: () {
    var formatter = DartFormatter(
        indent: options.indent,
        pageWidth: options.pageWidth,
        fixes: options.fixes);
    try {
      options.reporter.beforeFile(null, name);
      var source = SourceCode(input.toString(),
          uri: name,
          selectionStart: selectionStart,
          selectionLength: selectionLength);
      var output = formatter.formatSource(source);
      options.reporter
          .afterFile(null, name, output, changed: source.text != output.text);
      return;
    } on FormatterException catch (err) {
      stderr.writeln(err.message());
      exitCode = 65; // sysexits.h: EX_DATAERR
    } catch (err, stack) {
      stderr.writeln('''Hit a bug in the formatter when formatting stdin.
Please report at: github.com/dart-lang/dart_style/issues
$err
$stack''');
      exitCode = 70; // sysexits.h: EX_SOFTWARE
    }
  });
}

/// Formats all of the files and directories given by [paths].
void formatPaths(FormatterOptions options, List<String> paths) {
  for (var path in paths) {
    var directory = Directory(path);
    if (directory.existsSync()) {
      if (!processDirectory(options, directory)) {
        exitCode = 65;
      }
      continue;
    }

    var file = File(path);
    if (file.existsSync()) {
      if (!processFile(options, file)) {
        exitCode = 65;
      }
    } else {
      stderr.writeln('No file or directory found at "$path".');
    }
  }
}

/// Prints [error] and usage help then exits with exit code 64.
void usageError(ArgParser parser, String error) {
  printUsage(parser, error);
  exit(64);
}

void printUsage(ArgParser parser, [String error]) {
  var output = stdout;

  var message = 'Idiomatically formats Dart source code.';
  if (error != null) {
    message = error;
    output = stdout;
  }

  output.write('''$message

Usage:   dartfmt [options...] [files or directories...]

Example: dartfmt -w .
         Reformats every Dart file in the current directory tree.

${parser.usage}
''');
}