sdk/pkg/compiler/test/sourcemaps/tools/save.dart

// 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.

// @dart = 2.7

/// Loads a human-readable source map and outputs the source map file for it.

library save;

import 'dart:convert';
import 'dart:io';
import 'package:source_maps/source_maps.dart';
import '../helpers/lax_json.dart' as lazon;

void main(List<String> args) {
  if (args.isEmpty) {
    print('''
Usage: save <dir-containing 'out.js.map2'>
   or: save <human-readable-source-map-file> [<source-map-file>]''');
    exit(1);
  }

  File humanReadableSourceMapFile;
  File sourceMapFile;
  if (args.length == 1 && new Directory(args[0]).existsSync()) {
    humanReadableSourceMapFile = new File('${args[0]}/out.js.map2');
    sourceMapFile = new File('${args[0]}/out.js.map');
  } else {
    humanReadableSourceMapFile = new File(args[0]);
    if (args.length > 1) {
      sourceMapFile = new File(args[1]);
    }
  }

  String humanReadableSourceMap = humanReadableSourceMapFile.readAsStringSync();
  SingleMapping mapping =
      convertFromHumanReadableSourceMap(humanReadableSourceMap);

  if (sourceMapFile != null) {
    sourceMapFile.writeAsStringSync(json.encoder.convert(mapping.toJson()));
  } else {
    print(new JsonEncoder.withIndent('  ').convert(mapping.toJson()));
  }
}

SingleMapping convertFromHumanReadableSourceMap(String json) {
  Map inputMap = lazon.decode(json);
  Map urls = inputMap['sources'];
  List<String> sources = new List<String>.filled(urls.length, null);
  urls.forEach((Object index, Object url) {
    int i = int.parse(index);
    assert(sources[i] == null);
    sources[i] = url;
  });
  List lines = inputMap['lines'];
  Map<String, int> names = <String, int>{};
  Map<int, TargetLineEntry> lineEntryMap = {};

  for (Map line in lines) {
    String targetString = line['target'];
    String sourceString = line['source'];
    String name = line['name'];
    int nameIndex;
    if (name != null) {
      nameIndex = names.putIfAbsent(name, () => names.length);
    }

    int lineNo;
    int columnStart;
    int columnEnd;
    if (targetString != null) {
      int commaPos = targetString.indexOf(',');
      lineNo = int.parse(targetString.substring(0, commaPos)) - 1;
      if (lineNo < 0) {
        throw new ArgumentError('target line must be > 0: $lineNo');
      }
      targetString = targetString.substring(commaPos + 1);
      int dashPos = targetString.indexOf('-');
      columnStart = int.parse(targetString.substring(0, dashPos)) - 1;
      if (columnStart < 0) {
        throw new ArgumentError(
            'target column start must be > 0: $columnStart');
      }
      targetString = targetString.substring(dashPos + 1);
      if (!targetString.isEmpty) {
        columnEnd = int.parse(targetString) - 1;
        if (columnEnd < 0) {
          throw new ArgumentError('target column end must be > 0: $columnEnd');
        }
      }
    }
    int sourceUrlId;
    int sourceLine;
    int sourceColumn;
    if (sourceString != null) {
      int colonPos = sourceString.indexOf(':');
      sourceUrlId = int.parse(sourceString.substring(0, colonPos));
      if (sourceUrlId < 0) {
        throw new ArgumentError('source url id end must be > 0: $sourceUrlId');
      } else if (sourceUrlId >= sources.length) {
        throw new ArgumentError(
            'source url id end must be < ${sources.length}: $sourceUrlId');
      }

      sourceString = sourceString.substring(colonPos + 1);
      int commaPos = sourceString.indexOf(',');
      sourceLine = int.parse(sourceString.substring(0, commaPos)) - 1;
      if (sourceLine < 0) {
        throw new ArgumentError('source line end must be > 0: $sourceLine');
      }
      sourceString = sourceString.substring(commaPos + 1);
      sourceColumn = int.parse(sourceString) - 1;
      if (sourceColumn < 0) {
        throw new ArgumentError('source column must be > 0: $sourceColumn');
      }
    }

    TargetLineEntry lineEntry =
        lineEntryMap.putIfAbsent(lineNo, () => new TargetLineEntry(lineNo, []));
    lineEntry.entries.add(new TargetEntry(
        columnStart, sourceUrlId, sourceLine, sourceColumn, nameIndex));
    if (columnEnd != null) {
      lineEntry.entries.add(new TargetEntry(columnEnd));
    }
  }

  List<TargetLineEntry> lineEntries = lineEntryMap.values.toList();

  Map outputMap = {
    'version': 3,
    'sourceRoot': inputMap['sourceRoot'],
    'file': inputMap['file'],
    'sources': sources,
    'names': names.keys.toList(),
    'mappings': '',
  };

  SingleMapping mapping = new SingleMapping.fromJson(outputMap);
  mapping.lines.addAll(lineEntries);
  return mapping;
}