Add access to the isolate package-root/package-map in Platform.

sdk/lib/io/platform_impl.dart

Index: sdk/lib/io/platform_impl.dart
diff --git a/sdk/lib/io/platform_impl.dart b/sdk/lib/io/platform_impl.dart
index 6380e0d7c92f622495d3c9ca2149db2baafdfda9..f790b8c55e133b20cb15102b591a0517cac63266 100644
--- a/sdk/lib/io/platform_impl.dart
+++ b/sdk/lib/io/platform_impl.dart
@@ -21,7 +21,7 @@ class _Platform {
    * a non-empty name and a value separated by a '=' character.
    * The name does not contain a '=' character,
    * so the name is everything up to the first '=' character.
-   * Values are everything after the first '=' charcacter.
+   * Values are everything after the first '=' character.
    * A value may contain further '=' characters, and it may be empty.
    *
    * Returns an [OSError] if retrieving the environment fails.
@@ -29,13 +29,31 @@ class _Platform {
   external static _environment();
   external static List<String> _executableArguments();
   external static String _packageRoot();
+  external static _packageResolution();
   external static String _version();
 
   static String executable = _executable();
   static String resolvedExecutable = _resolvedExecutable();
   static String packageRoot = _packageRoot();
+  static var _resolution = () {
+    var res = _packageResolution();
+    // Do not give users access to the real map.
+    if (res is Map) res = new Map<String, Uri>.unmodifiable(res);
+    return res;
+  } ();
 
-  // Cache the OS environemnt. This can be an OSError instance if
+  static Uri get packageRootUri {
+    if (_resolution is Uri) return _resolution;

[Ivan Posva, 2015/08/26 04:29:36]

I'll implement these without going through native code. How about throwing
unsupported errors for now?

[Lasse Reichstein Nielsen, 2015/08/26 06:26:06]

That's fine. I'll just add the interface for now.

+    return null;
+  }
+
+  static Map<String, Uri> get packageMap {
+    if (_resolution is Map) return _resolution;
+    if (_resolution == null) return const <String, Uri>{};
+    return null;
+  }
+
+  // Cache the OS environment. This can be an OSError instance if
   // retrieving the environment failed.
   static var _environmentCache;