Use libraryFilters flag to speed up coverage collection (#104122)

* Use libraryFilters flag to speed up coverage collection

* Allow libraryNames to be null

* Unconditionally enable the reportLines flag

* Fix analysis errors

packages/flutter_tools/bin/fuchsia_tester.dart

@@ -112,16 +112,13 @@ Future<void> run(List<String> args) async {
     Directory testDirectory;
     CoverageCollector collector;
     if (argResults['coverage'] as bool) {
+      // If we have a specified coverage directory then accept all libraries by
+      // setting libraryNames to null.
+      final Set<String> libraryNames = coverageDirectory != null ? null :
+          <String>{FlutterProject.current().manifest.appName};
       collector = CoverageCollector(
         packagesPath: globals.fs.path.normalize(globals.fs.path.absolute(argResults[_kOptionPackages] as String)),
-        libraryPredicate: (String libraryName) {
-          // If we have a specified coverage directory then accept all libraries.
-          if (coverageDirectory != null) {
-            return true;
-          }
-          final String projectName = FlutterProject.current().manifest.appName;
-          return libraryName.contains(projectName);
-        });
+        libraryNames: libraryNames);
       if (!argResults.options.contains(_kOptionTestDirectory)) {
         throwToolExit('Use of --coverage requires setting --test-directory');
       }

packages/flutter_tools/lib/src/commands/test.dart

@@ -380,7 +380,7 @@ class TestCommand extends FlutterCommand with DeviceBasedDevelopmentArtifacts {
       final String projectName = flutterProject.manifest.appName;
       collector = CoverageCollector(
         verbose: !machine,
-        libraryPredicate: (String libraryName) => libraryName.contains(projectName),
+        libraryNames: <String>{projectName},
         packagesPath: buildInfo.packagesPath
       );
     }

packages/flutter_tools/lib/src/test/coverage_collector.dart

@@ -19,7 +19,7 @@ import 'watcher.dart';
 
 /// A class that collects code coverage data during test runs.
 class CoverageCollector extends TestWatcher {
-  CoverageCollector({this.libraryPredicate, this.verbose = true, @required this.packagesPath});
+  CoverageCollector({this.libraryNames, this.verbose = true, @required this.packagesPath});
 
   /// True when log messages should be emitted.
   final bool verbose;
@@ -31,9 +31,9 @@ class CoverageCollector extends TestWatcher {
   /// Map of file path to coverage hit map for that file.
   Map<String, coverage.HitMap> _globalHitmap;
 
-  /// Predicate function that returns true if the specified library URI should
-  /// be included in the computed coverage.
-  bool Function(String) libraryPredicate;
+  /// The names of the libraries to gather coverage for. If null, all libraries
+  /// will be accepted.
+  Set<String> libraryNames;
 
   @override
   Future<void> handleFinishedTest(TestDevice testDevice) async {
@@ -83,7 +83,7 @@ class CoverageCollector extends TestWatcher {
   Future<void> collectCoverageIsolate(Uri observatoryUri) async {
     assert(observatoryUri != null);
     _logMessage('collecting coverage data from $observatoryUri...');
-    final Map<String, dynamic> data = await collect(observatoryUri, libraryPredicate);
+    final Map<String, dynamic> data = await collect(observatoryUri, libraryNames);
     if (data == null) {
       throw Exception('Failed to collect coverage.');
     }
@@ -121,7 +121,7 @@ class CoverageCollector extends TestWatcher {
     final Future<void> collectionComplete = testDevice.observatoryUri
       .then((Uri observatoryUri) {
         _logMessage('collecting coverage data from $testDevice at $observatoryUri...');
-        return collect(observatoryUri, libraryPredicate)
+        return collect(observatoryUri, libraryNames)
           .then<void>((Map<String, dynamic> result) {
             if (result == null) {
               throw Exception('Failed to collect coverage.');
@@ -237,31 +237,57 @@ Future<FlutterVmService> _defaultConnect(Uri serviceUri) {
       serviceUri, compression: CompressionOptions.compressionOff, logger: globals.logger,);
 }
 
-Future<Map<String, dynamic>> collect(Uri serviceUri, bool Function(String) libraryPredicate, {
+Future<Map<String, dynamic>> collect(Uri serviceUri, Set<String> libraryNames, {
   bool waitPaused = false,
   String debugName,
   Future<FlutterVmService> Function(Uri) connector = _defaultConnect,
   @visibleForTesting bool forceSequential = false,
 }) async {
   final FlutterVmService vmService = await connector(serviceUri);
-  final Map<String, dynamic> result = await _getAllCoverage(vmService.service, libraryPredicate, forceSequential);
+  final Map<String, dynamic> result = await _getAllCoverage(vmService.service, libraryNames, forceSequential);
   await vmService.dispose();
   return result;
 }
 
 Future<Map<String, dynamic>> _getAllCoverage(
   vm_service.VmService service,
-  bool Function(String) libraryPredicate,
+  Set<String> libraryNames,
   bool forceSequential,
 ) async {
   final vm_service.Version version = await service.getVersion();
-  final bool reportLines = (version.major == 3 && version.minor >= 51) || version.major > 3;
+  final bool libraryFilters = (version.major == 3 && version.minor >= 57) || version.major > 3;
   final vm_service.VM vm = await service.getVM();
   final List<Map<String, dynamic>> coverage = <Map<String, dynamic>>[];
+  bool libraryPredicate(String libraryName) {
+    if (libraryNames == null) {
+      return true;
+    }
+    final Uri uri = Uri.parse(libraryName);
+    if (uri.scheme != 'package') {
+      return false;
+    }
+    final String scope = uri.path.split('/').first;
+    return libraryNames.contains(scope);
+  }
   for (final vm_service.IsolateRef isolateRef in vm.isolates) {
     if (isolateRef.isSystemIsolate) {
       continue;
     }
+    if (libraryFilters) {
+      final vm_service.SourceReport sourceReport = await service.getSourceReport(
+          isolateRef.id,
+          <String>['Coverage'],
+          forceCompile: true,
+          reportLines: true,
+          libraryFilters: libraryNames == null ? null : List<String>.from(
+              libraryNames.map((String name) => 'package:$name/')),
+        );
+      _buildCoverageMap(
+          <String, vm_service.Script>{},
+          <vm_service.SourceReport>[sourceReport],
+          coverage,
+        );
+    } else {
       vm_service.ScriptList scriptList;
       try {
         scriptList = await service.getScripts(isolateRef.id);
@@ -271,10 +297,10 @@ Future<Map<String, dynamic>> _getAllCoverage(
 
       final List<Future<void>> futures = <Future<void>>[];
       final Map<String, vm_service.Script> scripts = <String, vm_service.Script>{};
-    final Map<String, vm_service.SourceReport> sourceReports = <String, vm_service.SourceReport>{};
-    // For each ScriptRef loaded into the VM, load the corresponding Script and
-    // SourceReport object.
+      final List<vm_service.SourceReport> sourceReports = <vm_service.SourceReport>[];
 
+      // For each ScriptRef loaded into the VM, load the corresponding Script
+      // and SourceReport object.
       for (final vm_service.ScriptRef script in scriptList.scripts) {
         final String libraryUri = script.uri;
         if (!libraryPredicate(libraryUri)) {
@@ -286,28 +312,19 @@ Future<Map<String, dynamic>> _getAllCoverage(
           <String>['Coverage'],
           scriptId: scriptId,
           forceCompile: true,
-        reportLines: reportLines ? true : null,
+          reportLines: true,
         )
         .then((vm_service.SourceReport report) {
-        sourceReports[scriptId] = report;
+          sourceReports.add(report);
         });
         if (forceSequential) {
           await null;
         }
         futures.add(getSourceReport);
-      if (reportLines) {
-        continue;
-      }
-      final Future<void> getObject = service
-        .getObject(isolateRef.id, scriptId)
-        .then((vm_service.Obj response) {
-          final vm_service.Script script = response as vm_service.Script;
-          scripts[scriptId] = script;
-        });
-      futures.add(getObject);
       }
       await Future.wait(futures);
-    _buildCoverageMap(scripts, sourceReports, coverage, reportLines);
+      _buildCoverageMap(scripts, sourceReports, coverage);
+    }
   }
   return <String, dynamic>{'type': 'CodeCoverage', 'coverage': coverage};
 }
@@ -315,13 +332,11 @@ Future<Map<String, dynamic>> _getAllCoverage(
 // Build a hitmap of Uri -> Line -> Hit Count for each script object.
 void _buildCoverageMap(
   Map<String, vm_service.Script> scripts,
-  Map<String, vm_service.SourceReport> sourceReports,
+  List<vm_service.SourceReport> sourceReports,
   List<Map<String, dynamic>> coverage,
-  bool reportLines,
 ) {
   final Map<String, Map<int, int>> hitMaps = <String, Map<int, int>>{};
-  for (final String scriptId in sourceReports.keys) {
-    final vm_service.SourceReport sourceReport = sourceReports[scriptId];
+  for (final vm_service.SourceReport sourceReport  in sourceReports) {
     for (final vm_service.SourceReportRange range in sourceReport.ranges) {
       final vm_service.SourceReportCoverage coverage = range.coverage;
       // Coverage reports may sometimes be null for a Script.
@@ -335,24 +350,14 @@ void _buildCoverageMap(
       final Map<int, int> hitMap = hitMaps[uri];
       final List<int> hits = coverage.hits;
       final List<int> misses = coverage.misses;
-      final List<dynamic> tokenPositions = scripts[scriptRef.id]?.tokenPosTable;
-      // The token positions can be null if the script has no lines that may be
-      // covered. It will also be null if reportLines is true.
-      if (tokenPositions == null && !reportLines) {
-        continue;
-      }
       if (hits != null) {
-        for (final int hit in hits) {
-          final int line =
-              reportLines ? hit : _lineAndColumn(hit, tokenPositions)[0];
+        for (final int line in hits) {
           final int current = hitMap[line] ?? 0;
           hitMap[line] = current + 1;
         }
       }
       if (misses != null) {
-        for (final int miss in misses) {
-          final int line =
-              reportLines ? miss : _lineAndColumn(miss, tokenPositions)[0];
+        for (final int line in misses) {
           hitMap[line] ??= 0;
         }
       }
@@ -363,29 +368,6 @@ void _buildCoverageMap(
   });
 }
 
-// Binary search the token position table for the line and column which
-// corresponds to each token position.
-// The format of this table is described in https://github.com/dart-lang/sdk/blob/main/runtime/vm/service/service.md#script
-List<int> _lineAndColumn(int position, List<dynamic> tokenPositions) {
-  int min = 0;
-  int max = tokenPositions.length;
-  while (min < max) {
-    final int mid = min + ((max - min) >> 1);
-    final List<int> row = (tokenPositions[mid] as List<dynamic>).cast<int>();
-    if (row[1] > position) {
-      max = mid;
-    } else {
-      for (int i = 1; i < row.length; i += 2) {
-        if (row[i] == position) {
-          return <int>[row.first, row[i + 1]];
-        }
-      }
-      min = mid + 1;
-    }
-  }
-  throw StateError('Unreachable');
-}
-
 // Returns a JSON hit map backward-compatible with pre-1.16.0 SDKs.
 Map<String, dynamic> _toScriptCoverageJson(String scriptUri, Map<int, int> hitMap) {
   final Map<String, dynamic> json = <String, dynamic>{};