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 'dart:collection' show HashMap;
 
 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"
-/// }
-///
-/// If a key doesn't begin with `dart:` it is ignored.
-class SdkExtUriResolver extends UriResolver {
-  static const String SDK_EXT_NAME = '_sdkext';
-  static const String DART_COLON_PREFIX = 'dart:';
+/// Given a packageMap, check in each package's lib directory for the
+/// existence of an `_embedder.yaml` file. If the file contains a top level
+/// YamlMap, it will be added to the [embedderYamls] map.
+class EmbedderYamlLocator {
+  static const String EMBEDDER_FILE_NAME = '_embedder.yaml';
 
-  final Map<String, String> _urlMappings = <String, String>{};
+  // Map from package's library directory to the parsed
+  // YamlMap.
+  final Map<Folder, YamlMap> embedderYamls = new HashMap<Folder, YamlMap>();
 
-  /// Construct a [SdkExtUriResolver] from a package map
-  /// (see [PackageMapProvider]).
-  SdkExtUriResolver(Map<String, List<Folder>> packageMap) {
+  EmbedderYamlLocator(Map<String, List<Folder>> packageMap) {
+    if (packageMap != null) {
+      refresh(packageMap);
+    }
+  }
+
+  void refresh(Map<String, List<Folder>> packageMap) {
+    // Clear existing.
+    embedderYamls.clear();
     if (packageMap == null) {
       return;
     }
     packageMap.forEach(_processPackage);
   }
 
-  /// Number of sdk extensions.
+  /// Programatically add an _embedder.yaml mapping.
+  void addEmbedderYaml(Folder libDir, String embedderYaml) {
+    _processEmbedderYaml(libDir, embedderYaml);
+  }
+
+  /// Given a package [name] and a list of folders ([libDirs]),
+  /// add any found `_embedder.yaml` files.
+  void _processPackage(String name, List<Folder> libDirs) {
+    for (Folder libDir in libDirs) {
+      String embedderYaml = _readEmbedderYaml(libDir);
+      if (embedderYaml != null) {
+        _processEmbedderYaml(libDir, embedderYaml);
+      }
+    }
+  }
+
+  /// Given the yaml for an embedder ([embedderYaml]) and a folder
+  /// ([libDir]), setup the uri mapping.
+  void _processEmbedderYaml(Folder libDir, String embedderYaml) {
+    YamlNode yaml;
+    try {
+      yaml = loadYaml(embedderYaml);
+    } catch (_) {
+      // TODO(pquitslund): Notify developer that something is wrong with the
+      // _embedder.yaml file in libDir.
+      return;
+    }
+    if (yaml == null) {
+      // TODO(pquitslund): Notify developer that something is wrong with the
+      // _embedder.yaml file in libDir.
+      return;
+    }
+    if (yaml is! YamlMap) {
+      // TODO(pquitslund): Notify developer that something is wrong with the
+      // _embedder.yaml file in libDir.
+      return;
+    }
+    embedderYamls[libDir] = yaml;
+  }
+
+
+  /// Read the contents of [libDir]/[EMBEDDER_FILE_NAME] as a string.
+  /// Returns null if the file doesn't exist.
+  String _readEmbedderYaml(Folder libDir) {
+    File file = libDir.getChild(EMBEDDER_FILE_NAME);
+    try {
+      return file.readAsStringSync();
+    } on FileSystemException {
+      // File can't be read.
+      return null;
+    }
+  }
+}
+
+/// Given the [embedderYamls] from [EmbedderYamlLocator] check each one for the
+/// top level key 'embedder_libs'. Under the 'embedder_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:
+///
+/// embedder_libs:
+///   'dart:io': '../../sdk/io/io.dart'
+///
+/// If a key doesn't begin with `dart:` it is ignored.
+///
+class EmbedderUriResolver extends UriResolver {
+  static const String DART_COLON_PREFIX = 'dart:';
+
+  final Map<String, String> _urlMappings = <String, String>{};
+
+  /// Construct a [EmbedderUriResolver] from a package map
+  /// (see [PackageMapProvider]).
+  EmbedderUriResolver(Map<Folder, YamlMap> embedderYamls) {
+    if (embedderYamls == null) {
+      return;
+    }
+    embedderYamls.forEach(_processEmbedderYaml);
+  }
+
+  void _processEmbedderYaml(Folder libDir, YamlMap map) {
+    YamlNode embedder_libs = map['embedder_libs'];
+    if (embedder_libs == null) {
+      return;
+    }
+    if (embedder_libs is! YamlMap) {
+      return;
+    }
+    (embedder_libs as YamlMap).forEach((k, v) =>
+        _processEmbedderLibs(k, v, libDir));
+  }
+
+  /// Install the mapping from [name] to [libDir]/[file].
+  void _processEmbedderLibs(String name, String file, Folder libDir) {
+    if (!name.startsWith(DART_COLON_PREFIX)) {
+      // SDK libraries must begin with 'dart:'.
+      // TODO(pquitslund): Notify developer that something is wrong with the
+      // _embedder.yaml file in libDir.
+      return;
+    }
+    String key = name;
+    String value = libDir.canonicalizePath(file);
+    _urlMappings[key] = value;
+  }
+
+  /// 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);
-  }
-
   @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);
     }
   }
 
   @override
   Uri restoreAbsolute(Source source) {
     String extensionName = _findExtensionNameFor(source.fullName);
     if (extensionName != null) {
       return Uri.parse(extensionName);
     }
     // TODO(johnmccutchan): Handle restoring parts.
     return null;
   }
 
   /// Return the extension name for [fullName] or `null`.
   String _findExtensionNameFor(String fullName) {
-    var result;
+    String result;
     _urlMappings.forEach((extensionName, pathMapping) {
       if (pathMapping == fullName) {
         result = extensionName;
       }
     });
     return result;
   }
 
   /// Return the library name of [importUri].
   String _libraryName(Uri importUri) {
-    var uri = importUri.toString();
+    String uri = importUri.toString();
     int index = uri.indexOf('/');
     if (index >= 0) {
       return uri.substring(0, index);
     }
     return uri;
   }
 
   /// Return the part path of [importUri].
   String _partPath(Uri importUri) {
-    var uri = importUri.toString();
+    String 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.
-  void _processPackage(String name, List<Folder> libDirs) {
-    for (var libDir in libDirs) {
-      var sdkExt = _readDotSdkExt(libDir);
-      if (sdkExt != null) {
-        _processSdkExt(sdkExt, libDir);
-      }
-    }
-  }
-
-  /// Given the JSON for an SDK extension ([sdkExtJSON]) and a folder
-  /// ([libDir]), setup the uri mapping.
-  void _processSdkExt(String sdkExtJSON, Folder libDir) {
-    var sdkExt;
-    try {
-      sdkExt = JSON.decode(sdkExtJSON);
-    } catch (e) {
-      return;
-    }
-    if ((sdkExt == null) || (sdkExt is! Map)) {
-      return;
-    }
-    sdkExt.forEach((k, v) => _processSdkExtension(k, v, libDir));
-  }
-
-  /// Install the mapping from [name] to [libDir]/[file].
-  void _processSdkExtension(String name, String file, Folder libDir) {
-    if (!name.startsWith(DART_COLON_PREFIX)) {
-      // SDK extensions 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.
-  /// Returns null if the file doesn't exist.
-  String _readDotSdkExt(Folder libDir) {
-    var file = libDir.getChild(SDK_EXT_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));
+    String directory = pathos.dirname(libraryEntry.path);
+    Uri partUri = new Uri.file(pathos.join(directory, partPath));
     assert(partUri.isAbsolute);
     JavaFile javaFile = new JavaFile.fromUri(partUri);
     return new FileBasedSource(javaFile, importUri);
   }
 }