parseChromeCoverage (#281)

Towards dart-lang/test#36

Add `parseChromeCoverage` method to be used by `package:test` and internal tools. This method returns a hit-map based Dart report suitable for consumption by `package:coverage` to produce LCOV reports.

Author: grouma

CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.13.4 - 2020-01-23
+
+* Add `parseChromeCoverage` for creating a Dart based coverage report from a
+  Chrome coverage report.
+
 ## 0.13.3+3 - 2019-12-03
 
 * Re-loosen the dependency on the `vm_service` package from `>=1.0.0 < 2.1.2`

lib/coverage.dart

@@ -2,6 +2,7 @@
 // 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.
 
+export 'src/chrome.dart';
 export 'src/collect.dart';
 export 'src/formatter.dart';
 export 'src/hitmap.dart';

lib/src/chrome.dart

@@ -0,0 +1,155 @@
+// Copyright (c) 2020, 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:coverage/src/util.dart';
+import 'package:source_maps/parser.dart';
+
+/// Returns a Dart based hit-map containing coverage report for the provided
+/// Chrome [preciseCoverage].
+///
+/// [sourceProvider] returns the source content for the Chrome scriptId, or null
+/// if not available.
+///
+/// [sourceMapProvider] returns the associated source map content for the Chrome
+/// scriptId, or null if not available.
+///
+/// [sourceUriProvider] returns the uri for the provided sourceUrl and
+/// associated scriptId.
+///
+/// Chrome coverage information for which the corresponding source map or source
+/// content is null will be ignored.
+Future<Map<String, dynamic>> parseChromeCoverage(
+  List<Map<String, dynamic>> preciseCoverage,
+  Future<String> Function(String scriptId) sourceProvider,
+  Future<String> Function(String scriptId) sourceMapProvider,
+  Future<Uri> Function(String sourceUrl, String scriptId) sourceUriProvider,
+) async {
+  final coverageReport = <Uri, Map<int, bool>>{};
+  for (Map<String, dynamic> entry in preciseCoverage) {
+    final String scriptId = entry['scriptId'];
+
+    final mapResponse = await sourceMapProvider(scriptId);
+    if (mapResponse == null) continue;
+
+    final SingleMapping mapping = parse(mapResponse);
+
+    final compiledSource = await sourceProvider(scriptId);
+    if (compiledSource == null) continue;
+
+    final coverageInfo = _coverageInfoFor(entry);
+    final offsetCoverage = _offsetCoverage(coverageInfo, compiledSource.length);
+    final coveredPositions = _coveredPositions(compiledSource, offsetCoverage);
+
+    for (var lineEntry in mapping.lines) {
+      for (var columnEntry in lineEntry.entries) {
+        if (columnEntry.sourceUrlId == null) continue;
+        final sourceUrl = mapping.urls[columnEntry.sourceUrlId];
+
+        // Ignore coverage information for the SDK.
+        if (sourceUrl.startsWith('org-dartlang-sdk:')) continue;
+
+        final uri = await sourceUriProvider(sourceUrl, scriptId);
+        final coverage = coverageReport.putIfAbsent(uri, () => <int, bool>{});
+
+        coverage[columnEntry.sourceLine + 1] = coveredPositions
+            .contains(_Position(lineEntry.line + 1, columnEntry.column + 1));
+      }
+    }
+  }
+
+  final coverageHitMaps = <Uri, Map<int, int>>{};
+  coverageReport.forEach((uri, coverage) {
+    final hitMap = <int, int>{};
+    for (var line in coverage.keys.toList()..sort()) {
+      hitMap[line] = coverage[line] ? 1 : 0;
+    }
+    coverageHitMaps[uri] = hitMap;
+  });
+
+  final allCoverage = <Map<String, dynamic>>[];
+  coverageHitMaps.forEach((uri, hitMap) {
+    allCoverage.add(toScriptCoverageJson(uri, hitMap));
+  });
+  return <String, dynamic>{'type': 'CodeCoverage', 'coverage': allCoverage};
+}
+
+/// Returns all covered positions in a provided source.
+Set<_Position> _coveredPositions(
+    String compiledSource, List<bool> offsetCoverage) {
+  final positions = Set<_Position>();
+  // Line is 1 based.
+  var line = 1;
+  // Column is 1 based.
+  var column = 0;
+  for (var offset = 0; offset < compiledSource.length; offset++) {
+    if (compiledSource[offset] == '\n') {
+      line++;
+      column = 0;
+    } else {
+      column++;
+    }
+    if (offsetCoverage[offset]) positions.add(_Position(line, column));
+  }
+  return positions;
+}
+
+/// Returns coverage information for a Chrome entry.
+List<_CoverageInfo> _coverageInfoFor(Map<String, dynamic> entry) {
+  final result = <_CoverageInfo>[];
+  for (Map<String, dynamic> functions in entry['functions']) {
+    for (Map<String, dynamic> range in functions['ranges']) {
+      result.add(_CoverageInfo(
+        range['startOffset'],
+        range['endOffset'],
+        range['count'] > 0,
+      ));
+    }
+  }
+  return result;
+}
+
+/// Returns the coverage information for each offset.
+List<bool> _offsetCoverage(List<_CoverageInfo> coverageInfo, int sourceLength) {
+  final offsetCoverage = List.filled(sourceLength, false);
+
+  // Sort coverage information by their size.
+  // Coverage information takes granularity as precedence.
+  coverageInfo.sort((a, b) =>
+      (b.endOffset - b.startOffset).compareTo(a.endOffset - a.startOffset));
+
+  for (var range in coverageInfo) {
+    for (var i = range.startOffset; i < range.endOffset; i++) {
+      offsetCoverage[i] = range.isCovered;
+    }
+  }
+
+  return offsetCoverage;
+}
+
+class _CoverageInfo {
+  _CoverageInfo(this.startOffset, this.endOffset, this.isCovered);
+
+  /// 0 based byte offset.
+  final int startOffset;
+
+  /// 0 based byte offset.
+  final int endOffset;
+
+  final bool isCovered;
+}
+
+/// A covered position in a source file where [line] and [column] are 1 based.
+class _Position {
+  _Position(this.line, this.column);
+
+  final int line;
+  final int column;
+
+  @override
+  int get hashCode => hash2(line, column);
+
+  @override
+  bool operator ==(dynamic o) =>
+      o is _Position && o.line == line && o.column == column;
+}

lib/src/collect.dart

@@ -217,32 +217,11 @@ Future<List<Map<String, dynamic>>> _getCoverageJson(VmService service,
   // Output JSON
   final coverage = <Map<String, dynamic>>[];
   hitMaps.forEach((uri, hitMap) {
-    coverage.add(_toScriptCoverageJson(uri, hitMap));
+    coverage.add(toScriptCoverageJson(uri, hitMap));
   });
   return coverage;
 }
 
-/// Returns a JSON hit map backward-compatible with pre-1.16.0 SDKs.
-Map<String, dynamic> _toScriptCoverageJson(
-    Uri scriptUri, Map<int, int> hitMap) {
-  final json = <String, dynamic>{};
-  final hits = <int>[];
-  hitMap.forEach((line, hitCount) {
-    hits.add(line);
-    hits.add(hitCount);
-  });
-  json['source'] = '$scriptUri';
-  json['script'] = {
-    'type': '@Script',
-    'fixedId': true,
-    'id': 'libraries/1/scripts/${Uri.encodeComponent(scriptUri.toString())}',
-    'uri': '$scriptUri',
-    '_kind': 'library',
-  };
-  json['hits'] = hits;
-  return json;
-}
-
 class StdoutLog extends Log {
   @override
   void warning(String message) => print(message);

lib/src/util.dart

@@ -72,3 +72,39 @@ Future<int> getOpenPort() async {
     await socket.close();
   }
 }
+
+/// Returns a JSON hit map backward-compatible with pre-1.16.0 SDKs.
+Map<String, dynamic> toScriptCoverageJson(Uri scriptUri, Map<int, int> hitMap) {
+  final json = <String, dynamic>{};
+  final hits = <int>[];
+  hitMap.forEach((line, hitCount) {
+    hits.add(line);
+    hits.add(hitCount);
+  });
+  json['source'] = '$scriptUri';
+  json['script'] = {
+    'type': '@Script',
+    'fixedId': true,
+    'id': 'libraries/1/scripts/${Uri.encodeComponent(scriptUri.toString())}',
+    'uri': '$scriptUri',
+    '_kind': 'library',
+  };
+  json['hits'] = hits;
+  return json;
+}
+
+/// Generates a hash code for two objects.
+int hash2(dynamic a, dynamic b) =>
+    _finish(_combine(_combine(0, a.hashCode), b.hashCode));
+
+int _combine(int hash, int value) {
+  hash = 0x1fffffff & (hash + value);
+  hash = 0x1fffffff & (hash + ((0x0007ffff & hash) << 10));
+  return hash ^ (hash >> 6);
+}
+
+int _finish(int hash) {
+  hash = 0x1fffffff & (hash + ((0x03ffffff & hash) << 3));
+  hash = hash ^ (hash >> 11);
+  return 0x1fffffff & (hash + ((0x00003fff & hash) << 15));
+}

pubspec.yaml

@@ -1,5 +1,5 @@
 name: coverage
-version: 0.13.3+3
+version: 0.13.4
 author: Dart Team <[email protected]>
 description: Coverage data manipulation and formatting
 homepage: https://github.com/dart-lang/coverage

test/chrome_test.dart

@@ -0,0 +1,63 @@
+// Copyright (c) 2020, 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:coverage/coverage.dart';
+import 'package:test/test.dart';
+
+Future<String> sourceMapProvider(String scriptId) async {
+  // The scriptId for the main_test.ddc.js in the sample report is 37.
+  if (scriptId != '37') return null;
+  return File('test/test_files/main_test.ddc.js.map').readAsString();
+}
+
+Future<String> sourceProvider(String scriptId) async {
+  // The scriptId for the main_test.ddc.js in the sample report is 37.
+  if (scriptId != '37') return null;
+  return File('test/test_files/main_test.ddc.js').readAsString();
+}
+
+Future<Uri> sourceUriProvider(String sourceUrl, String scriptId) async =>
+    Uri.parse(sourceUrl);
+
+void main() {
+  test('reports correctly', () async {
+    final preciseCoverage = json.decode(
+        await File('test/test_files/chrome_precise_report.txt').readAsString());
+
+    final report = await parseChromeCoverage(
+      // ignore: avoid_as
+      (preciseCoverage as List).cast(),
+      sourceProvider,
+      sourceMapProvider,
+      sourceUriProvider,
+    );
+
+    final coverage = report['coverage'];
+    expect(coverage.length, equals(1));
+
+    final sourceReport = coverage.first;
+    expect(sourceReport['source'], equals('main_test.dart'));
+
+    final Map<int, int> expectedHits = {
+      5: 1,
+      6: 1,
+      7: 1,
+      8: 0,
+      10: 1,
+      11: 1,
+      13: 1,
+      14: 1,
+      15: 1,
+    };
+
+    final List<int> hitMap = sourceReport['hits'];
+    expect(hitMap.length, equals(expectedHits.keys.length * 2));
+    for (var i = 0; i < hitMap.length; i += 2) {
+      expect(expectedHits[hitMap[i]], equals(hitMap[i + 1]));
+    }
+  });
+}

test/test_all.dart

@@ -4,6 +4,7 @@
 
 import 'package:test/test.dart';
 
+import 'chrome_test.dart' as chrome;
 import 'collect_coverage_api_test.dart' as collect_coverage_api;
 import 'collect_coverage_test.dart' as collect_coverage;
 import 'lcov_test.dart' as lcov;
@@ -18,4 +19,5 @@ void main() {
   group('resolver', resolver.main);
   group('run_and_collect', run_and_collect.main);
   group('util', util.main);
+  group('chrome', chrome.main);
 }