Add package config support to dart:isolate

sdk/lib/isolate/isolate.dart

 // Copyright (c) 2012, 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.
 
 /**
  * Concurrent programming using _isolates_:
  * independent workers that are similar to threads
  * but don't share memory,
  * communicating only via messages.
  */
@@ skipping 109 matching lines @@
   /**
    * Return the current [Isolate].
    *
    * The isolate gives access to the capabilities needed to inspect,
    * pause or kill the isolate, and allows granting these capabilities
    * to others.
    */
   external static Isolate get current;
 
   /**
+   * Returns the package root of the current isolate, if any.
+   *
+   * If the isolate is using a [packageConfig] or the isolate has not been
+   * setup for package resolution, this getter returns `null`, otherwise it
+   * returns the package root - a directory that package URIs are resolved
+   * against.
+   */
+  external static Future<Uri> get packageRoot;
+
+  /**
+   * Returns the package root of the current isolate, if any.
+   *
+   * If the isolate is using a [packageRoot] or the isolate has not been
+   * setup for package resolution, this getter returns `null`, otherwise it
+   * returns the package config URI.
+   */
+  external static Future<Uri> get packageConfig;
+
+  /**
+   * Maps a package: URI to a non-package Uri.
+   *
+   * If there is no valid mapping from the package: URI in the current
+   * isolate, then this call returns `null`. Non-package: URIs are
+   * returned unmodified.
+   */
+  external static Future<Uri> resolvePackageUri(Uri packageUri);
+
+  /**
    * Creates and spawns an isolate that shares the same code as the current
    * isolate.
    *
    * The argument [entryPoint] specifies the entry point of the spawned
    * isolate. It must be a top-level function or a static method that
    * takes one argument - that is, one-parameter functions that can be
    * compile-time constant function values.
    * It is not allowed to pass the value of function expressions or an instance
    * method extracted from an object.
    *
@@ skipping 75 matching lines @@
    * If the [packageRoot] parameter is provided, it is used to find the location
    * of package sources in the spawned isolate.
    *
    * The `packageRoot` URI must be a "file" or "http"/"https" URI that specifies
    * a directory. If it doesn't end in a slash, one will be added before
    * using the URI, and any query or fragment parts are ignored.
    * Package imports (like `"package:foo/bar.dart"`) in the new isolate are
    * resolved against this location, as by
    * `packageRoot.resolve("foo/bar.dart")`.
    *
+   * If the [packageConfig] parameter is provided, then it is used to find the
+   * location of a package resolution configuration file for the spawned
+   * isolate.
+   *

[kevmoo, 2016/01/13 02:21:19]

Need notes on the behavior if both `packageRoot` and `packageConfig` are
provided

+   * If the [automaticPackageResolution] parameter is provided, then the

[kevmoo, 2016/01/13 02:21:19]

provided => `true`.

+   * location of the package sources in the spawned isolate is automatically
+   * determined.

[kevmoo, 2016/01/13 02:21:19]

determined how?

How does this relate to packageRoot and packageConfig?

+   *
    * The [environment] is a mapping from strings to strings which the
    * spawned isolate uses when looking up [String.fromEnvironment] values.
    * The system may add its own entries to environment as well.
    * If `environment` is omitted, the spawned isolate has the same environment
    * declarations as the spawning isolate.
    *
    * WARNING: The [environment] parameter is not implemented on all
    * platforms yet.
    *
    * Returns a future that will complete with an [Isolate] instance if the
    * spawning succeeded. It will complete with an error otherwise.
    */
   external static Future<Isolate> spawnUri(
       Uri uri,
       List<String> args,
       var message,
       {bool paused: false,
        SendPort onExit,
        SendPort onError,
        bool errorsAreFatal,
        bool checked,
        Map<String, String> environment,
-       Uri packageRoot});
+       Uri packageRoot,
+       Uri packageConfig,
+       bool automaticPackageResolution: false});
 
   /**
    * Requests the isolate to pause.
    *
    * The isolate should stop handling events by pausing its event queue.
    * The request will eventually make the isolate stop doing anything.
    * It will be handled before any other messages that are later sent to the
    * isolate from the current isolate, but no other guarantees are provided.
    *
    * The event loop may be paused before previously sent, but not yet exeuted,
@@ skipping 356 matching lines @@
  * as the original error, but has no other features of the original error.
  */
 class RemoteError implements Error {
   final String _description;
   final StackTrace stackTrace;
   RemoteError(String description, String stackDescription)
       : _description = description,
         stackTrace = new StackTrace.fromString(stackDescription);
   String toString() => _description;
 }