pkg/analyzer/lib/src/dart/sdk/sdk.dart - sdk.git - Git at Google

 // 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.

 import 'dart:collection';
 import 'dart:io' as io;

 import 'package:analyzer/dart/analysis/features.dart';
 import 'package:analyzer/dart/analysis/utilities.dart';
 import 'package:analyzer/exception/exception.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/java_engine_io.dart';
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:pub_semver/pub_semver.dart';
 import 'package:yaml/yaml.dart';

 Version languageVersionFromSdkVersion(String sdkVersionStr) {
   var sdkVersionParts = sdkVersionStr.split('.');
   var sdkVersionMajor = int.parse(sdkVersionParts[0]);
   var sdkVersionMinor = int.parse(sdkVersionParts[1]);
   return Version(sdkVersionMajor, sdkVersionMinor, 0);
 }

 /// An abstract implementation of a Dart SDK in which the available libraries
 /// are stored in a library map. Subclasses are responsible for populating the
 /// library map.
 abstract class AbstractDartSdk implements DartSdk {
   /// The resource provider used to access the file system.
   late final ResourceProvider resourceProvider;

   /// A mapping from Dart library URI's to the library represented by that URI.
   LibraryMap libraryMap = LibraryMap();

   /// The mapping from Dart URI's to the corresponding sources.
   final Map<String, Source?> _uriToSourceMap = HashMap<String, Source?>();

   @override
   List<SdkLibraryImpl> get sdkLibraries => libraryMap.sdkLibraries;

   /// Return the path separator used by the resource provider.
   String get separator => resourceProvider.pathContext.separator;

   @override
   List<String> get uris => libraryMap.uris;

   /// Return info for debugging https://github.com/dart-lang/sdk/issues/35226.
   Map<String, Object> debugInfo() {
     return <String, Object>{
       'runtimeType': '$runtimeType',
       'libraryMap': libraryMap.debugInfo(),
     };
   }

   @override
   Source? fromFileUri(Uri uri) {
     File file =
         resourceProvider.getFile(resourceProvider.pathContext.fromUri(uri));
     String? path = _getPath(file);
     if (path == null) {
       return null;
     }
     try {
       return file.createSource(Uri.parse(path));
     } on FormatException catch (exception, stackTrace) {
       AnalysisEngine.instance.instrumentationService.logInfo(
           "Failed to create URI: $path",
           CaughtException(exception, stackTrace));
     }
     return null;
   }

   String? getRelativePathFromFile(File file);

   @override
   SdkLibrary? getSdkLibrary(String dartUri) => libraryMap.getLibrary(dartUri);

   Source? internalMapDartUri(String dartUri) {
     // TODO(brianwilkerson) Figure out how to unify the implementations in the
     // two subclasses.
     String libraryName;
     String relativePath;
     int index = dartUri.indexOf('/');
     if (index >= 0) {
       libraryName = dartUri.substring(0, index);
       relativePath = dartUri.substring(index + 1);
     } else {
       libraryName = dartUri;
       relativePath = "";
     }
     SdkLibrary? library = getSdkLibrary(libraryName);
     if (library == null) {
       return null;
     }
     String srcPath;
     if (relativePath.isEmpty) {
       srcPath = library.path;
     } else {
       String libraryPath = library.path;
       int index = libraryPath.lastIndexOf(separator);
       if (index == -1) {
         index = libraryPath.lastIndexOf('/');
         if (index == -1) {
           return null;
         }
       }
       String prefix = libraryPath.substring(0, index + 1);
       srcPath = '$prefix$relativePath';
     }
     String filePath = srcPath.replaceAll('/', separator);
     try {
       File file = resourceProvider.getFile(filePath);
       return file.createSource(Uri.parse(dartUri));
     } on FormatException {
       return null;
     }
   }

   @override
   Source? mapDartUri(String dartUri) {
     Source? source = _uriToSourceMap[dartUri];
     if (source == null) {
       source = internalMapDartUri(dartUri);
       _uriToSourceMap[dartUri] = source;
     }
     return source;
   }

   @override
   Uri? pathToUri(String path) {
     var file = resourceProvider.getFile(path);

     var uriStr = _getPath(file);
     if (uriStr == null) {
       return null;
     }

     try {
       return Uri.parse(uriStr);
     } on FormatException {
       return null;
     }
   }

   /// TODO(scheglov) This name is misleading, returns `dart:foo/bar.dart`.
   String? _getPath(File file) {
     // TODO(scheglov) Ideally, all `SdkLibrary` should have `File`, with
     // an absolute path, not a relative `path`. For now, we do this only
     // for building SDK summary with `dart:ui`, included from outside
     // of the SDK root.
     for (final library in libraryMap.sdkLibraries) {
       final pathContext = resourceProvider.pathContext;
       if (pathContext.isAbsolute(library.path)) {
         if (library.path == file.path) {
           return library.shortName;
         }
       }
     }
     for (final library in libraryMap.sdkLibraries) {
       final pathContext = resourceProvider.pathContext;
       if (pathContext.isAbsolute(library.path)) {
         final libraryFile = resourceProvider.getFile(library.path);
         final libraryFolder = libraryFile.parent;
         if (libraryFolder.contains(file.path)) {
           final relPath = pathContext
               .relative(file.path, from: libraryFolder.path)
               .replaceAll(separator, '/');
           return '${library.shortName}/$relPath';
         }
       }
     }

     List<SdkLibrary> libraries = libraryMap.sdkLibraries;
     int length = libraries.length;
     String? filePath = getRelativePathFromFile(file);
     if (filePath == null) {
       return null;
     }
     List<String> paths = <String>[];
     for (int i = 0; i < length; i++) {
       SdkLibrary library = libraries[i];
       String libraryPath = library.path.replaceAll('/', separator);
       if (filePath == libraryPath) {
         return library.shortName;
       }
       paths.add(libraryPath);
     }
     for (int i = 0; i < length; i++) {
       SdkLibrary library = libraries[i];
       String libraryPath = paths[i];
       int index = libraryPath.lastIndexOf(separator);
       if (index >= 0) {
         String prefix = libraryPath.substring(0, index + 1);
         if (filePath.startsWith(prefix)) {
           String relPath =
               filePath.substring(prefix.length).replaceAll(separator, '/');
           return '${library.shortName}/$relPath';
         }
       }
     }
     return null;
   }
 }

 /// An SDK backed by URI mappings derived from an `_embedder.yaml` file.
 class EmbedderSdk extends AbstractDartSdk {
   static const String _DART_COLON_PREFIX = 'dart:';

   static const String _EMBEDDED_LIB_MAP_KEY = 'embedded_libs';

   late final Version _languageVersion;

   final Map<String, String> _urlMappings = HashMap<String, String>();

   /// TODO(scheglov) Make [languageVersion] required.
   /// https://github.com/dart-lang/sdk/issues/42890
   EmbedderSdk(
     ResourceProvider resourceProvider,
     Map<Folder, YamlMap>? embedderYamls, {
     Version? languageVersion,
   }) {
     this.resourceProvider = resourceProvider;
     _languageVersion =
         languageVersion ?? languageVersionFromSdkVersion(io.Platform.version);
     embedderYamls?.forEach(_processEmbedderYaml);
   }

   @override
   String? get allowedExperimentsJson {
     var coreSource = mapDartUri('dart:core');
     if (coreSource != null) {
       var coreFile = resourceProvider.getFile(coreSource.fullName);
       var embeddedFolder = coreFile.parent.parent;
       try {
         return embeddedFolder
             .getChildAssumingFolder('_internal')
             .getChildAssumingFile('allowed_experiments.json')
             .readAsStringSync();
       } catch (_) {}
     }
     return null;
   }

   @override
   Version get languageVersion => _languageVersion;

   @override
   // TODO(danrubel) Determine SDK version
   String get sdkVersion => '0';

   /// The url mappings for this SDK.
   Map<String, String> get urlMappings => _urlMappings;

   @override
   String getRelativePathFromFile(File file) => file.path;

   @override
   Source? internalMapDartUri(String dartUri) {
     String libraryName;
     String relativePath;
     int index = dartUri.indexOf('/');
     if (index >= 0) {
       libraryName = dartUri.substring(0, index);
       relativePath = dartUri.substring(index + 1);
     } else {
       libraryName = dartUri;
       relativePath = "";
     }
     SdkLibrary? library = getSdkLibrary(libraryName);
     if (library == null) {
       return null;
     }
     String srcPath;
     if (relativePath.isEmpty) {
       srcPath = library.path;
     } else {
       String libraryPath = library.path;
       int index = libraryPath.lastIndexOf(separator);
       if (index == -1) {
         index = libraryPath.lastIndexOf('/');
         if (index == -1) {
           return null;
         }
       }
       String prefix = libraryPath.substring(0, index + 1);
       srcPath = '$prefix$relativePath';
     }
     String filePath = srcPath.replaceAll('/', separator);
     try {
       File file = resourceProvider.getFile(filePath);
       return file.createSource(Uri.parse(dartUri));
     } on FormatException {
       return null;
     }
   }

   /// Install the mapping from [name] to [libDir]/[file].
   void _processEmbeddedLibs(String name, String file, Folder libDir) {
     if (!name.startsWith(_DART_COLON_PREFIX)) {
       // SDK libraries must begin with 'dart:'.
       return;
     }
     String libPath = libDir.canonicalizePath(file);
     _urlMappings[name] = libPath;
     SdkLibraryImpl library = SdkLibraryImpl(name);
     library.path = libPath;
     libraryMap.setLibrary(name, library);
   }

   /// Given the 'embedderYamls' from [EmbedderYamlLocator] check each one for
   /// the top level key 'embedded_libs'. Under the 'embedded_libs' key are key
   /// value pairs. Each key is a 'dart:' library uri and each value is a path
   /// (relative to the directory containing `_embedder.yaml`) to a dart script
   /// for the given library. For example:
   ///
   /// embedded_libs:
   ///   'dart:io': '../../sdk/io/io.dart'
   ///
   /// If a key doesn't begin with `dart:` it is ignored.
   void _processEmbedderYaml(Folder libDir, YamlMap map) {
     YamlNode embeddedLibs = map[_EMBEDDED_LIB_MAP_KEY];
     if (embeddedLibs is YamlMap) {
       embeddedLibs.forEach((k, v) => _processEmbeddedLibs(k, v, libDir));
     }
   }
 }

 /// A Dart SDK installed in a specified directory. Typical Dart SDK layout is
 /// something like...
 ///
 ///     dart-sdk/
 ///        bin/
 ///           dart[.exe]  <-- VM
 ///        lib/
 ///           core/
 ///              core.dart
 ///              ... other core library files ...
 ///           ... other libraries ...
 ///        util/
 ///           ... Dart utilities ...
 ///     Chromium/   <-- Dartium typically exists in a sibling directory
 class FolderBasedDartSdk extends AbstractDartSdk {
   /// The name of the directory within the SDK directory that contains
   /// executables.
   static const String _BIN_DIRECTORY_NAME = "bin";

   /// The name of the directory within the SDK directory that contains
   /// documentation for the libraries.
   static const String _DOCS_DIRECTORY_NAME = "docs";

   /// The name of the directory within the SDK directory that contains the
   /// sdk_library_metadata directory.
   static const String _INTERNAL_DIR = "_internal";

   /// The name of the sdk_library_metadata directory that contains the package
   /// holding the libraries.dart file.
   static const String _SDK_LIBRARY_METADATA_DIR = "sdk_library_metadata";

   /// The name of the directory within the sdk_library_metadata that contains
   /// libraries.dart.
   static const String _SDK_LIBRARY_METADATA_LIB_DIR = "lib";

   /// The name of the directory within the SDK directory that contains the
   /// libraries.
   static const String _LIB_DIRECTORY_NAME = "lib";

   /// The name of the libraries file.
   static const String _LIBRARIES_FILE = "libraries.dart";

   /// The name of the pub executable on windows.
   static const String _PUB_EXECUTABLE_NAME_WIN = "pub.bat";

   /// The name of the pub executable on non-windows operating systems.
   static const String _PUB_EXECUTABLE_NAME = "pub";

   /// The name of the file within the SDK directory that contains the version
   /// number of the SDK.
   static const String _VERSION_FILE_NAME = "version";

   /// The directory containing the SDK.
   final Folder _sdkDirectory;

   /// The directory within the SDK directory that contains the libraries.
   Folder? _libraryDirectory;

   /// The revision number of this SDK, or `"0"` if the revision number cannot be
   /// discovered.
   String? _sdkVersion;

   /// The cached language version of this SDK.
   Version? _languageVersion;

   /// The file containing the pub executable.
   File? _pubExecutable;

   /// Initialize a newly created SDK to represent the Dart SDK installed in the
   /// [sdkDirectory].
   FolderBasedDartSdk(ResourceProvider resourceProvider, Folder sdkDirectory)
       : _sdkDirectory = sdkDirectory {
     this.resourceProvider = resourceProvider;
     libraryMap = initialLibraryMap();
   }

   @override
   String get allowedExperimentsJson {
     return _sdkDirectory
         .getChildAssumingFolder('lib')
         .getChildAssumingFolder('_internal')
         .getChildAssumingFile('allowed_experiments.json')
         .readAsStringSync();
   }

   /// Return the directory containing the SDK.
   Folder get directory => _sdkDirectory;

   /// Return the directory containing documentation for the SDK.
   Folder get docDirectory =>
       _sdkDirectory.getChildAssumingFolder(_DOCS_DIRECTORY_NAME);

   @override
   Version get languageVersion {
     if (_languageVersion == null) {
       var sdkVersionStr = _sdkDirectory
           .getChildAssumingFile(_VERSION_FILE_NAME)
           .readAsStringSync();
       _languageVersion = languageVersionFromSdkVersion(sdkVersionStr);
     }

     return _languageVersion!;
   }

   /// Return the directory within the SDK directory that contains the libraries.
   Folder get libraryDirectory {
     return _libraryDirectory ??=
         _sdkDirectory.getChildAssumingFolder(_LIB_DIRECTORY_NAME);
   }

   /// Return the file containing the Pub executable, or `null` if it does not
   /// exist.
   File get pubExecutable {
     return _pubExecutable ??= _sdkDirectory
         .getChildAssumingFolder(_BIN_DIRECTORY_NAME)
         .getChildAssumingFile(OSUtilities.isWindows()
             ? _PUB_EXECUTABLE_NAME_WIN
             : _PUB_EXECUTABLE_NAME);
   }

   /// Return the revision number of this SDK, or `"0"` if the revision number
   /// cannot be discovered.
   @override
   String get sdkVersion {
     if (_sdkVersion == null) {
       File revisionFile =
           _sdkDirectory.getChildAssumingFile(_VERSION_FILE_NAME);
       try {
         String revision = revisionFile.readAsStringSync();
         _sdkVersion = revision.trim();
       } on FileSystemException {
         return _sdkVersion = DartSdk.DEFAULT_VERSION;
       }
     }
     return _sdkVersion!;
   }

   /// Determine the search order for trying to locate the [_LIBRARIES_FILE].
   Iterable<File> get _libraryMapLocations sync* {
     yield libraryDirectory
         .getChildAssumingFolder(_INTERNAL_DIR)
         .getChildAssumingFolder(_SDK_LIBRARY_METADATA_DIR)
         .getChildAssumingFolder(_SDK_LIBRARY_METADATA_LIB_DIR)
         .getChildAssumingFile(_LIBRARIES_FILE);
     yield libraryDirectory
         .getChildAssumingFolder(_INTERNAL_DIR)
         .getChildAssumingFile(_LIBRARIES_FILE);
   }

   /// Return info for debugging https://github.com/dart-lang/sdk/issues/35226.
   @override
   Map<String, Object> debugInfo() {
     var result = super.debugInfo();
     result['directory'] = _sdkDirectory.path;
     return result;
   }

   @override
   String? getRelativePathFromFile(File file) {
     String filePath = file.path;
     String libPath = libraryDirectory.path;
     if (!filePath.startsWith("$libPath$separator")) {
       return null;
     }
     return filePath.substring(libPath.length + 1);
   }

   /// Read all of the configuration files to initialize the library maps.
   /// Return the initialized library map.
   LibraryMap initialLibraryMap() {
     List<String> searchedPaths = <String>[];
     late StackTrace lastStackTrace;
     late Object lastException;
     for (File librariesFile in _libraryMapLocations) {
       try {
         String contents = librariesFile.readAsStringSync();
         return SdkLibrariesReader().readFromFile(librariesFile, contents);
       } catch (exception, stackTrace) {
         print('[exception: $exception][stackTrace: $stackTrace]');
         searchedPaths.add(librariesFile.path);
         lastException = exception;
         lastStackTrace = stackTrace;
       }
     }
     StringBuffer buffer = StringBuffer();
     buffer.writeln('Could not initialize the library map from $searchedPaths');
     if (resourceProvider is MemoryResourceProvider) {
       (resourceProvider as MemoryResourceProvider).writeOn(buffer);
     }
     // TODO(39284): should this exception be silent?
     AnalysisEngine.instance.instrumentationService.logException(
         SilentException(buffer.toString(), lastException, lastStackTrace));
     return LibraryMap();
   }

   @override
   Source? internalMapDartUri(String dartUri) {
     String libraryName;
     String relativePath;
     int index = dartUri.indexOf('/');
     if (index >= 0) {
       libraryName = dartUri.substring(0, index);
       relativePath = dartUri.substring(index + 1);
     } else {
       libraryName = dartUri;
       relativePath = "";
     }
     SdkLibrary? library = getSdkLibrary(libraryName);
     if (library == null) {
       return null;
     }
     try {
       File file = libraryDirectory.getChildAssumingFile(library.path);
       if (relativePath.isNotEmpty) {
         File relativeFile = file.parent.getChildAssumingFile(relativePath);
         if (relativeFile.path == file.path) {
           // The relative file is the library, so return a Source for the
           // library rather than the part format.
           return file.createSource(Uri.parse(library.shortName));
         }
         file = relativeFile;
       }
       return file.createSource(Uri.parse(dartUri));
     } on FormatException {
       return null;
     }
   }
 }

 /// An object used to read and parse the libraries file
 /// (dart-sdk/lib/_internal/sdk_library_metadata/lib/libraries.dart) for
 /// information about the libraries in an SDK. The library information is
 /// represented as a Dart file containing a single top-level variable whose
 /// value is a const map. The keys of the map are the names of libraries defined
 /// in the SDK and the values in the map are info objects defining the library.
 /// For example, a subset of a typical SDK might have a libraries file that
 /// looks like the following:
 ///
 ///     final Map<String, LibraryInfo> LIBRARIES = const <LibraryInfo> {
 ///       // Used by VM applications
 ///       "builtin" : const LibraryInfo(
 ///         "builtin/builtin_runtime.dart",
 ///         category: "Server",
 ///         platforms: VM_PLATFORM),
 ///
 ///       "compiler" : const LibraryInfo(
 ///         "compiler/compiler.dart",
 ///         category: "Tools",
 ///         platforms: 0),
 ///     };
 class SdkLibrariesReader {
   /// Return the library map read from the given [file], given that the content
   /// of the file is already known to be [libraryFileContents].
   LibraryMap readFromFile(File file, String libraryFileContents) =>
       readFromSource(file.createSource(), libraryFileContents);

   /// Return the library map read from the given [source], given that the
   /// content of the file is already known to be [libraryFileContents].
   LibraryMap readFromSource(Source source, String libraryFileContents) {
     // TODO(paulberry): initialize the feature set appropriately based on the
     // version of the SDK we are reading, and enable flags.
     var featureSet = FeatureSet.latestLanguageVersion();

     var parseResult = parseString(
       content: libraryFileContents,
       featureSet: featureSet,
       throwIfDiagnostics: false,
       path: source.fullName,
     );
     var unit = parseResult.unit;

     var libraryBuilder = SdkLibrariesReader_LibraryBuilder();
     if (parseResult.errors.isEmpty) {
       unit.accept(libraryBuilder);
     }
     return libraryBuilder.librariesMap;
   }
 }
	// 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.

	import 'dart:collection';
	import 'dart:io' as io;

	import 'package:analyzer/dart/analysis/features.dart';
	import 'package:analyzer/dart/analysis/utilities.dart';
	import 'package:analyzer/exception/exception.dart';
	import 'package:analyzer/file_system/file_system.dart';
	import 'package:analyzer/file_system/memory_file_system.dart';
	import 'package:analyzer/src/generated/engine.dart';
	import 'package:analyzer/src/generated/java_engine_io.dart';
	import 'package:analyzer/src/generated/sdk.dart';
	import 'package:analyzer/src/generated/source.dart';
	import 'package:pub_semver/pub_semver.dart';
	import 'package:yaml/yaml.dart';

	Version languageVersionFromSdkVersion(String sdkVersionStr) {
	var sdkVersionParts = sdkVersionStr.split('.');
	var sdkVersionMajor = int.parse(sdkVersionParts[0]);
	var sdkVersionMinor = int.parse(sdkVersionParts[1]);
	return Version(sdkVersionMajor, sdkVersionMinor, 0);
	}

	/// An abstract implementation of a Dart SDK in which the available libraries
	/// are stored in a library map. Subclasses are responsible for populating the
	/// library map.
	abstract class AbstractDartSdk implements DartSdk {
	/// The resource provider used to access the file system.
	late final ResourceProvider resourceProvider;

	/// A mapping from Dart library URI's to the library represented by that URI.
	LibraryMap libraryMap = LibraryMap();

	/// The mapping from Dart URI's to the corresponding sources.
	final Map<String, Source?> _uriToSourceMap = HashMap<String, Source?>();

	@override
	List<SdkLibraryImpl> get sdkLibraries => libraryMap.sdkLibraries;

	/// Return the path separator used by the resource provider.
	String get separator => resourceProvider.pathContext.separator;

	@override
	List<String> get uris => libraryMap.uris;

	/// Return info for debugging https://github.com/dart-lang/sdk/issues/35226.
	Map<String, Object> debugInfo() {
	return <String, Object>{
	'runtimeType': '$runtimeType',
	'libraryMap': libraryMap.debugInfo(),
	};
	}

	@override
	Source? fromFileUri(Uri uri) {
	File file =
	resourceProvider.getFile(resourceProvider.pathContext.fromUri(uri));
	String? path = _getPath(file);
	if (path == null) {
	return null;
	}
	try {
	return file.createSource(Uri.parse(path));
	} on FormatException catch (exception, stackTrace) {
	AnalysisEngine.instance.instrumentationService.logInfo(
	"Failed to create URI: $path",
	CaughtException(exception, stackTrace));
	}
	return null;
	}

	String? getRelativePathFromFile(File file);

	@override
	SdkLibrary? getSdkLibrary(String dartUri) => libraryMap.getLibrary(dartUri);

	Source? internalMapDartUri(String dartUri) {
	// TODO(brianwilkerson) Figure out how to unify the implementations in the
	// two subclasses.
	String libraryName;
	String relativePath;
	int index = dartUri.indexOf('/');
	if (index >= 0) {
	libraryName = dartUri.substring(0, index);
	relativePath = dartUri.substring(index + 1);
	} else {
	libraryName = dartUri;
	relativePath = "";
	}
	SdkLibrary? library = getSdkLibrary(libraryName);
	if (library == null) {
	return null;
	}
	String srcPath;
	if (relativePath.isEmpty) {
	srcPath = library.path;
	} else {
	String libraryPath = library.path;
	int index = libraryPath.lastIndexOf(separator);
	if (index == -1) {
	index = libraryPath.lastIndexOf('/');
	if (index == -1) {
	return null;
	}
	}
	String prefix = libraryPath.substring(0, index + 1);
	srcPath = '$prefix$relativePath';
	}
	String filePath = srcPath.replaceAll('/', separator);
	try {
	File file = resourceProvider.getFile(filePath);
	return file.createSource(Uri.parse(dartUri));
	} on FormatException {
	return null;
	}
	}

	@override
	Source? mapDartUri(String dartUri) {
	Source? source = _uriToSourceMap[dartUri];
	if (source == null) {
	source = internalMapDartUri(dartUri);
	_uriToSourceMap[dartUri] = source;
	}
	return source;
	}

	@override
	Uri? pathToUri(String path) {
	var file = resourceProvider.getFile(path);

	var uriStr = _getPath(file);
	if (uriStr == null) {
	return null;
	}

	try {
	return Uri.parse(uriStr);
	} on FormatException {
	return null;
	}
	}

	/// TODO(scheglov) This name is misleading, returns `dart:foo/bar.dart`.
	String? _getPath(File file) {
	// TODO(scheglov) Ideally, all `SdkLibrary` should have `File`, with
	// an absolute path, not a relative `path`. For now, we do this only
	// for building SDK summary with `dart:ui`, included from outside
	// of the SDK root.
	for (final library in libraryMap.sdkLibraries) {
	final pathContext = resourceProvider.pathContext;
	if (pathContext.isAbsolute(library.path)) {
	if (library.path == file.path) {
	return library.shortName;
	}
	}
	}
	for (final library in libraryMap.sdkLibraries) {
	final pathContext = resourceProvider.pathContext;
	if (pathContext.isAbsolute(library.path)) {
	final libraryFile = resourceProvider.getFile(library.path);
	final libraryFolder = libraryFile.parent;
	if (libraryFolder.contains(file.path)) {
	final relPath = pathContext
	.relative(file.path, from: libraryFolder.path)
	.replaceAll(separator, '/');
	return '${library.shortName}/$relPath';
	}
	}
	}

	List<SdkLibrary> libraries = libraryMap.sdkLibraries;
	int length = libraries.length;
	String? filePath = getRelativePathFromFile(file);
	if (filePath == null) {
	return null;
	}
	List<String> paths = <String>[];
	for (int i = 0; i < length; i++) {
	SdkLibrary library = libraries[i];
	String libraryPath = library.path.replaceAll('/', separator);
	if (filePath == libraryPath) {
	return library.shortName;
	}
	paths.add(libraryPath);
	}
	for (int i = 0; i < length; i++) {
	SdkLibrary library = libraries[i];
	String libraryPath = paths[i];
	int index = libraryPath.lastIndexOf(separator);
	if (index >= 0) {
	String prefix = libraryPath.substring(0, index + 1);
	if (filePath.startsWith(prefix)) {
	String relPath =
	filePath.substring(prefix.length).replaceAll(separator, '/');
	return '${library.shortName}/$relPath';
	}
	}
	}
	return null;
	}
	}

	/// An SDK backed by URI mappings derived from an `_embedder.yaml` file.
	class EmbedderSdk extends AbstractDartSdk {
	static const String _DART_COLON_PREFIX = 'dart:';

	static const String _EMBEDDED_LIB_MAP_KEY = 'embedded_libs';

	late final Version _languageVersion;

	final Map<String, String> _urlMappings = HashMap<String, String>();

	/// TODO(scheglov) Make [languageVersion] required.
	/// https://github.com/dart-lang/sdk/issues/42890
	EmbedderSdk(
	ResourceProvider resourceProvider,
	Map<Folder, YamlMap>? embedderYamls, {
	Version? languageVersion,
	}) {
	this.resourceProvider = resourceProvider;
	_languageVersion =
	languageVersion ?? languageVersionFromSdkVersion(io.Platform.version);
	embedderYamls?.forEach(_processEmbedderYaml);
	}

	@override
	String? get allowedExperimentsJson {
	var coreSource = mapDartUri('dart:core');
	if (coreSource != null) {
	var coreFile = resourceProvider.getFile(coreSource.fullName);
	var embeddedFolder = coreFile.parent.parent;
	try {
	return embeddedFolder
	.getChildAssumingFolder('_internal')
	.getChildAssumingFile('allowed_experiments.json')
	.readAsStringSync();
	} catch (_) {}
	}
	return null;
	}

	@override
	Version get languageVersion => _languageVersion;

	@override
	// TODO(danrubel) Determine SDK version
	String get sdkVersion => '0';

	/// The url mappings for this SDK.
	Map<String, String> get urlMappings => _urlMappings;

	@override
	String getRelativePathFromFile(File file) => file.path;

	@override
	Source? internalMapDartUri(String dartUri) {
	String libraryName;
	String relativePath;
	int index = dartUri.indexOf('/');
	if (index >= 0) {
	libraryName = dartUri.substring(0, index);
	relativePath = dartUri.substring(index + 1);
	} else {
	libraryName = dartUri;
	relativePath = "";
	}
	SdkLibrary? library = getSdkLibrary(libraryName);
	if (library == null) {
	return null;
	}
	String srcPath;
	if (relativePath.isEmpty) {
	srcPath = library.path;
	} else {
	String libraryPath = library.path;
	int index = libraryPath.lastIndexOf(separator);
	if (index == -1) {
	index = libraryPath.lastIndexOf('/');
	if (index == -1) {
	return null;
	}
	}
	String prefix = libraryPath.substring(0, index + 1);
	srcPath = '$prefix$relativePath';
	}
	String filePath = srcPath.replaceAll('/', separator);
	try {
	File file = resourceProvider.getFile(filePath);
	return file.createSource(Uri.parse(dartUri));
	} on FormatException {
	return null;
	}
	}

	/// Install the mapping from [name] to [libDir]/[file].
	void _processEmbeddedLibs(String name, String file, Folder libDir) {
	if (!name.startsWith(_DART_COLON_PREFIX)) {
	// SDK libraries must begin with 'dart:'.
	return;
	}
	String libPath = libDir.canonicalizePath(file);
	_urlMappings[name] = libPath;
	SdkLibraryImpl library = SdkLibraryImpl(name);
	library.path = libPath;
	libraryMap.setLibrary(name, library);
	}

	/// Given the 'embedderYamls' from [EmbedderYamlLocator] check each one for
	/// the top level key 'embedded_libs'. Under the 'embedded_libs' key are key
	/// value pairs. Each key is a 'dart:' library uri and each value is a path
	/// (relative to the directory containing `_embedder.yaml`) to a dart script
	/// for the given library. For example:
	///
	/// embedded_libs:
	/// 'dart:io': '../../sdk/io/io.dart'
	///
	/// If a key doesn't begin with `dart:` it is ignored.
	void _processEmbedderYaml(Folder libDir, YamlMap map) {
	YamlNode embeddedLibs = map[_EMBEDDED_LIB_MAP_KEY];
	if (embeddedLibs is YamlMap) {
	embeddedLibs.forEach((k, v) => _processEmbeddedLibs(k, v, libDir));
	}
	}
	}

	/// A Dart SDK installed in a specified directory. Typical Dart SDK layout is
	/// something like...
	///
	/// dart-sdk/
	/// bin/
	/// dart[.exe] <-- VM
	/// lib/
	/// core/
	/// core.dart
	/// ... other core library files ...
	/// ... other libraries ...
	/// util/
	/// ... Dart utilities ...
	/// Chromium/ <-- Dartium typically exists in a sibling directory
	class FolderBasedDartSdk extends AbstractDartSdk {
	/// The name of the directory within the SDK directory that contains
	/// executables.
	static const String _BIN_DIRECTORY_NAME = "bin";

	/// The name of the directory within the SDK directory that contains
	/// documentation for the libraries.
	static const String _DOCS_DIRECTORY_NAME = "docs";

	/// The name of the directory within the SDK directory that contains the
	/// sdk_library_metadata directory.
	static const String _INTERNAL_DIR = "_internal";

	/// The name of the sdk_library_metadata directory that contains the package
	/// holding the libraries.dart file.
	static const String _SDK_LIBRARY_METADATA_DIR = "sdk_library_metadata";

	/// The name of the directory within the sdk_library_metadata that contains
	/// libraries.dart.
	static const String _SDK_LIBRARY_METADATA_LIB_DIR = "lib";

	/// The name of the directory within the SDK directory that contains the
	/// libraries.
	static const String _LIB_DIRECTORY_NAME = "lib";

	/// The name of the libraries file.
	static const String _LIBRARIES_FILE = "libraries.dart";

	/// The name of the pub executable on windows.
	static const String _PUB_EXECUTABLE_NAME_WIN = "pub.bat";

	/// The name of the pub executable on non-windows operating systems.
	static const String _PUB_EXECUTABLE_NAME = "pub";

	/// The name of the file within the SDK directory that contains the version
	/// number of the SDK.
	static const String _VERSION_FILE_NAME = "version";

	/// The directory containing the SDK.
	final Folder _sdkDirectory;

	/// The directory within the SDK directory that contains the libraries.
	Folder? _libraryDirectory;

	/// The revision number of this SDK, or `"0"` if the revision number cannot be
	/// discovered.
	String? _sdkVersion;

	/// The cached language version of this SDK.
	Version? _languageVersion;

	/// The file containing the pub executable.
	File? _pubExecutable;

	/// Initialize a newly created SDK to represent the Dart SDK installed in the
	/// [sdkDirectory].
	FolderBasedDartSdk(ResourceProvider resourceProvider, Folder sdkDirectory)
	: _sdkDirectory = sdkDirectory {
	this.resourceProvider = resourceProvider;
	libraryMap = initialLibraryMap();
	}

	@override
	String get allowedExperimentsJson {
	return _sdkDirectory
	.getChildAssumingFolder('lib')
	.getChildAssumingFolder('_internal')
	.getChildAssumingFile('allowed_experiments.json')
	.readAsStringSync();
	}

	/// Return the directory containing the SDK.
	Folder get directory => _sdkDirectory;

	/// Return the directory containing documentation for the SDK.
	Folder get docDirectory =>
	_sdkDirectory.getChildAssumingFolder(_DOCS_DIRECTORY_NAME);

	@override
	Version get languageVersion {
	if (_languageVersion == null) {
	var sdkVersionStr = _sdkDirectory
	.getChildAssumingFile(_VERSION_FILE_NAME)
	.readAsStringSync();
	_languageVersion = languageVersionFromSdkVersion(sdkVersionStr);
	}

	return _languageVersion!;
	}

	/// Return the directory within the SDK directory that contains the libraries.
	Folder get libraryDirectory {
	return _libraryDirectory ??=
	_sdkDirectory.getChildAssumingFolder(_LIB_DIRECTORY_NAME);
	}

	/// Return the file containing the Pub executable, or `null` if it does not
	/// exist.
	File get pubExecutable {
	return _pubExecutable ??= _sdkDirectory
	.getChildAssumingFolder(_BIN_DIRECTORY_NAME)
	.getChildAssumingFile(OSUtilities.isWindows()
	? _PUB_EXECUTABLE_NAME_WIN
	: _PUB_EXECUTABLE_NAME);
	}

	/// Return the revision number of this SDK, or `"0"` if the revision number
	/// cannot be discovered.
	@override
	String get sdkVersion {
	if (_sdkVersion == null) {
	File revisionFile =
	_sdkDirectory.getChildAssumingFile(_VERSION_FILE_NAME);
	try {
	String revision = revisionFile.readAsStringSync();
	_sdkVersion = revision.trim();
	} on FileSystemException {
	return _sdkVersion = DartSdk.DEFAULT_VERSION;
	}
	}
	return _sdkVersion!;
	}

	/// Determine the search order for trying to locate the [_LIBRARIES_FILE].
	Iterable<File> get _libraryMapLocations sync* {
	yield libraryDirectory
	.getChildAssumingFolder(_INTERNAL_DIR)
	.getChildAssumingFolder(_SDK_LIBRARY_METADATA_DIR)
	.getChildAssumingFolder(_SDK_LIBRARY_METADATA_LIB_DIR)
	.getChildAssumingFile(_LIBRARIES_FILE);
	yield libraryDirectory
	.getChildAssumingFolder(_INTERNAL_DIR)
	.getChildAssumingFile(_LIBRARIES_FILE);
	}

	/// Return info for debugging https://github.com/dart-lang/sdk/issues/35226.
	@override
	Map<String, Object> debugInfo() {
	var result = super.debugInfo();
	result['directory'] = _sdkDirectory.path;
	return result;
	}

	@override
	String? getRelativePathFromFile(File file) {
	String filePath = file.path;
	String libPath = libraryDirectory.path;
	if (!filePath.startsWith("$libPath$separator")) {
	return null;
	}
	return filePath.substring(libPath.length + 1);
	}

	/// Read all of the configuration files to initialize the library maps.
	/// Return the initialized library map.
	LibraryMap initialLibraryMap() {
	List<String> searchedPaths = <String>[];
	late StackTrace lastStackTrace;
	late Object lastException;
	for (File librariesFile in _libraryMapLocations) {
	try {
	String contents = librariesFile.readAsStringSync();
	return SdkLibrariesReader().readFromFile(librariesFile, contents);
	} catch (exception, stackTrace) {
	print('[exception: $exception][stackTrace: $stackTrace]');
	searchedPaths.add(librariesFile.path);
	lastException = exception;
	lastStackTrace = stackTrace;
	}
	}
	StringBuffer buffer = StringBuffer();
	buffer.writeln('Could not initialize the library map from $searchedPaths');
	if (resourceProvider is MemoryResourceProvider) {
	(resourceProvider as MemoryResourceProvider).writeOn(buffer);
	}
	// TODO(39284): should this exception be silent?
	AnalysisEngine.instance.instrumentationService.logException(
	SilentException(buffer.toString(), lastException, lastStackTrace));
	return LibraryMap();
	}

	@override
	Source? internalMapDartUri(String dartUri) {
	String libraryName;
	String relativePath;
	int index = dartUri.indexOf('/');
	if (index >= 0) {
	libraryName = dartUri.substring(0, index);
	relativePath = dartUri.substring(index + 1);
	} else {
	libraryName = dartUri;
	relativePath = "";
	}
	SdkLibrary? library = getSdkLibrary(libraryName);
	if (library == null) {
	return null;
	}
	try {
	File file = libraryDirectory.getChildAssumingFile(library.path);
	if (relativePath.isNotEmpty) {
	File relativeFile = file.parent.getChildAssumingFile(relativePath);
	if (relativeFile.path == file.path) {
	// The relative file is the library, so return a Source for the
	// library rather than the part format.
	return file.createSource(Uri.parse(library.shortName));
	}
	file = relativeFile;
	}
	return file.createSource(Uri.parse(dartUri));
	} on FormatException {
	return null;
	}
	}
	}

	/// An object used to read and parse the libraries file
	/// (dart-sdk/lib/_internal/sdk_library_metadata/lib/libraries.dart) for
	/// information about the libraries in an SDK. The library information is
	/// represented as a Dart file containing a single top-level variable whose
	/// value is a const map. The keys of the map are the names of libraries defined
	/// in the SDK and the values in the map are info objects defining the library.
	/// For example, a subset of a typical SDK might have a libraries file that
	/// looks like the following:
	///
	/// final Map<String, LibraryInfo> LIBRARIES = const <LibraryInfo> {
	/// // Used by VM applications
	/// "builtin" : const LibraryInfo(
	/// "builtin/builtin_runtime.dart",
	/// category: "Server",
	/// platforms: VM_PLATFORM),
	///
	/// "compiler" : const LibraryInfo(
	/// "compiler/compiler.dart",
	/// category: "Tools",
	/// platforms: 0),
	/// };
	class SdkLibrariesReader {
	/// Return the library map read from the given [file], given that the content
	/// of the file is already known to be [libraryFileContents].
	LibraryMap readFromFile(File file, String libraryFileContents) =>
	readFromSource(file.createSource(), libraryFileContents);

	/// Return the library map read from the given [source], given that the
	/// content of the file is already known to be [libraryFileContents].
	LibraryMap readFromSource(Source source, String libraryFileContents) {
	// TODO(paulberry): initialize the feature set appropriately based on the
	// version of the SDK we are reading, and enable flags.
	var featureSet = FeatureSet.latestLanguageVersion();

	var parseResult = parseString(
	content: libraryFileContents,
	featureSet: featureSet,
	throwIfDiagnostics: false,
	path: source.fullName,
	);
	var unit = parseResult.unit;

	var libraryBuilder = SdkLibrariesReader_LibraryBuilder();
	if (parseResult.errors.isEmpty) {
	unit.accept(libraryBuilder);
	}
	return libraryBuilder.librariesMap;
	}
	}