Add _embedder.yaml support to analyzer and analysis_server

pkg/analyzer/lib/source/embedder.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.
 
-library source.sdk_ext;
+library source.embedder;
 
-import 'dart:convert';
 import 'dart:core' hide Resource;
 
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/generated/java_io.dart' show JavaFile;
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/source_io.dart' show FileBasedSource;
 import 'package:path/path.dart' as pathos;
+import 'package:yaml/yaml.dart';
 
 /// Given a packageMap (see [PackageMapProvider]), check in each package's lib
-/// directory for the existence of a `_sdkext` file. This file must contain a
-/// JSON encoded map. Each key in the map is a `dart:` library name. Each value
-/// is a path (relative to the directory containing `_sdkext`) to a dart script
-/// for the given library. For example:
-/// {
-///   "dart:sky": "../sdk_ext/dart_sky.dart"
-/// }
+/// directory for the existence of a `_embedder.yaml` file. This file must
+/// contain a yaml map with the top level key 'embedder_libs'. Under the
+/// 'embedder_libs' key are key value pairs. Each key is a 'dart:' library uri
+/// Each value is a path (relative to the directory containing `_embedder.yaml`)
+/// to a dart script for the given library. For example:
+/// embedder_libs:
+///   'dart:io': '../../sdk/io/io.dart'
 ///
 /// If a key doesn't begin with `dart:` it is ignored.
-class SdkExtUriResolver extends UriResolver {
-  static const String SDK_EXT_NAME = '_sdkext';
+///
+class EmbedderUriResolver extends UriResolver {
+  static const String EMBEDDER_FILE_NAME = '_embedder.yaml';
   static const String DART_COLON_PREFIX = 'dart:';
 
   final Map<String, String> _urlMappings = <String, String>{};
 
-  /// Construct a [SdkExtUriResolver] from a package map
+  /// Construct a [EmbedderUriResolver] from a package map
   /// (see [PackageMapProvider]).
-  SdkExtUriResolver(Map<String, List<Folder>> packageMap) {
+  EmbedderUriResolver(Map<String, List<Folder>> packageMap) {
     if (packageMap == null) {
       return;
     }
     packageMap.forEach(_processPackage);
   }
 
-  /// Number of sdk extensions.
+  /// Number of embedder libraries.
   int get length => _urlMappings.length;
 
   /// Return the path mapping for [libName] or null if there is none.
   String operator [](String libName) => _urlMappings[libName];
 
-  /// Programmatically add a new SDK extension given a JSON description
-  /// ([sdkExtJSON]) and a lib directory ([libDir]).
-  void addSdkExt(String sdkExtJSON, Folder libDir) {
-    _processSdkExt(sdkExtJSON, libDir);
+  /// Programmatically add a new embedder given a yaml description
+  /// ([embedderYaml]) and a lib directory ([libDir]).
+  void addEmbedderYaml(String embedderYaml, Folder libDir) {
+    _processEmbedderYaml(embedderYaml, libDir);
   }
 
   @override
   Source resolveAbsolute(Uri importUri, [Uri actualUri]) {
     String libraryName = _libraryName(importUri);
     String partPath = _partPath(importUri);
     // Lookup library name in mappings.
     String mapping = _urlMappings[libraryName];
     if (mapping == null) {
       // Not found.
       return null;
     }
-    // This mapping points to the main entry file of the sdk extension.
+    // This mapping points to the main entry file of the dart: library.
     Uri libraryEntry = new Uri.file(mapping);
     if (!libraryEntry.isAbsolute) {
       // We expect an absolute path.
       return null;
     }
 
     if (partPath != null) {
       return _resolvePart(libraryEntry, partPath, importUri);
     } else {
       return _resolveEntry(libraryEntry, importUri);
@@ skipping 35 matching lines @@
   String _partPath(Uri importUri) {
     var uri = importUri.toString();
     int index = uri.indexOf('/');
     if (index >= 0) {
       return uri.substring(index + 1);
     }
     return null;
   }
 
   /// Given a package [name] and a list of folders ([libDirs]),
-  /// add any found sdk extensions.
+  /// add any found `_embedder.yaml` files.
   void _processPackage(String name, List<Folder> libDirs) {
     for (var libDir in libDirs) {
-      var sdkExt = _readDotSdkExt(libDir);
-      if (sdkExt != null) {
-        _processSdkExt(sdkExt, libDir);
+      var embedderYaml = _readEmbedderYaml(libDir);
+      if (embedderYaml != null) {
+        _processEmbedderYaml(embedderYaml, libDir);
       }
     }
   }
 
-  /// Given the JSON for an SDK extension ([sdkExtJSON]) and a folder
+  /// Given the yaml for an embedder ([embedderYaml]) and a folder
   /// ([libDir]), setup the uri mapping.
-  void _processSdkExt(String sdkExtJSON, Folder libDir) {
-    var sdkExt;
+  void _processEmbedderYaml(String embedderYaml, Folder libDir) {
+    YamlNode yaml;
     try {
-      sdkExt = JSON.decode(sdkExtJSON);
+      yaml = loadYaml(embedderYaml);
     } catch (e) {

[pquitslund, 2015/11/11 19:19:09]

Maybe a TODO to do some error handling down the road?

[Cutch, 2015/11/12 14:13:43]

Done.

       return;
     }
-    if ((sdkExt == null) || (sdkExt is! Map)) {
+    if ((yaml == null) || (yaml is! YamlMap)) {
       return;
     }
-    sdkExt.forEach((k, v) => _processSdkExtension(k, v, libDir));
+    YamlNode embedder_libs = (yaml as YamlMap)['embedder_libs'];
+    if ((embedder_libs == null) || (embedder_libs is! YamlMap)) {

[pquitslund, 2015/11/11 19:19:09]

Maybe just:

if (embedder_libs is! YamlMap) {
   ...
}

The null check is unneeded I think?

[Brian Wilkerson, 2015/11/11 22:09:14]

Nope. e is! T is always true (unless T is Object, dynamic, or Null).

[Cutch, 2015/11/12 14:13:43]

Acknowledged.

[Cutch, 2015/11/12 14:13:43]

Acknowledged.

+      return;
+    }
+    (embedder_libs as YamlMap).forEach((k, v) =>
+        _processEmbedderLibs(k, v, libDir));
   }
 
   /// Install the mapping from [name] to [libDir]/[file].
-  void _processSdkExtension(String name, String file, Folder libDir) {
+  void _processEmbedderLibs(String name, String file, Folder libDir) {
     if (!name.startsWith(DART_COLON_PREFIX)) {
-      // SDK extensions must begin with 'dart:'.
+      // SDK libraries must begin with 'dart:'.
       return;
     }
     var key = name;
     var value = libDir.canonicalizePath(file);
     _urlMappings[key] = value;
   }
 
-  /// Read the contents of [libDir]/[SDK_EXT_NAME] as a string.
+  /// Read the contents of [libDir]/[EMBEDDER_FILE_NAME] as a string.
   /// Returns null if the file doesn't exist.
-  String _readDotSdkExt(Folder libDir) {
-    var file = libDir.getChild(SDK_EXT_NAME);
+  String _readEmbedderYaml(Folder libDir) {
+    var file = libDir.getChild(EMBEDDER_FILE_NAME);
     try {
       return file.readAsStringSync();
     } on FileSystemException {
       // File can't be read.
       return null;
     }
   }
 
   /// Resolve an import of an sdk extension.
   Source _resolveEntry(Uri libraryEntry, Uri importUri) {
     // Library entry.
     JavaFile javaFile = new JavaFile.fromUri(libraryEntry);
     return new FileBasedSource(javaFile, importUri);
   }
 
   /// Resolve a 'part' statement inside an sdk extension.
   Source _resolvePart(Uri libraryEntry, String partPath, Uri importUri) {
     // Library part.
     var directory = pathos.dirname(libraryEntry.path);
     var partUri = new Uri.file(pathos.join(directory, partPath));
     assert(partUri.isAbsolute);
     JavaFile javaFile = new JavaFile.fromUri(partUri);
     return new FileBasedSource(javaFile, importUri);
   }
 }