Removed fixed dependencies

packages/isolate/lib/isolate_runner.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 isolate.isolate_runner;
+
+import "dart:async";
+import "dart:isolate";
+
+import 'ports.dart';
+import 'runner.dart';
+import 'src/lists.dart';
+
+// Command tags. Shared between IsolateRunner and IsolateRunnerRemote.
+const int _SHUTDOWN = 0;
+const int _RUN = 1;
+
+/// An easier to use interface on top of an [Isolate].
+///
+/// Wraps an `Isolate` and allows pausing, killing and inspecting
+/// the isolate more conveniently than the raw `Isolate` methods.
+///
+/// Also allows running simple functions in the other isolate, and get back
+/// the result.
+class IsolateRunner implements Runner {
+  /// The underlying [Isolate] object of the isolate being controlled.
+  final Isolate isolate;
+
+  /// Command port for the [IsolateRunnerRemote].
+  final SendPort _commandPort;
+
+  /// Future returned by [onExit]. Set when [onExit] is first read.
+  Future _onExitFuture;
+
+  /// Create an [IsolateRunner] wrapper for [isolate]
+  ///
+  /// The preferred way to create an `IsolateRunner` is to use [spawn]
+  /// to create a new isolate and a runner for it.
+  ///
+  /// This constructor allows creating a runner for an already existing
+  /// isolate.
+  /// The [commandPort] must be the [IsolateRunnerRemote.commandPort] of
+  /// a remote running in that isolate.
+  IsolateRunner(this.isolate, SendPort commandPort)
+      : _commandPort = commandPort;
+
+  /// Create a new [Isolate], as by [Isolate.spawn] and wrap that.
+  ///
+  /// The returned [IsolateRunner] forwards operations to the new isolate,
+  /// and keeps a port open in the new isolate that receives commands
+  /// from the `IsolateRunner`. Remember to [close] the `IsolateRunner` when
+  /// it's no longer needed.
+  ///
+  /// The created isolate is set to have errors not be fatal.
+  static Future<IsolateRunner> spawn() async {
+    var channel = new SingleResponseChannel();
+    var isolate = await Isolate.spawn(IsolateRunnerRemote._create,
+                                      channel.port);
+    // The runner can be used to run multiple independent functions.
+    // An accidentally uncaught error shouldn't ruin it for everybody else.
+    isolate.setErrorsFatal(false);
+    var pingChannel = new SingleResponseChannel();
+    isolate.ping(pingChannel.port);
+    var commandPort = await channel.result;
+    var result = new IsolateRunner(isolate, commandPort);
+    // Guarantees that setErrorsFatal has completed.
+    await pingChannel.result;
+    return result;
+  }
+
+  /// Closes the `IsolateRunner` communication down.
+  ///
+  /// If the isolate isn't running something else to keep it alive,
+  /// this will also make the isolate shut down.
+  ///
+  /// Can be used to create an isolate, use [run] to start a service, and
+  /// then drop the connection and let the service control the isolate's
+  /// life cycle.
+  Future close() {
+    var channel = new SingleResponseChannel();
+    _commandPort.send(list2(_SHUTDOWN, channel.port));
+    return channel.result;
+  }
+
+  /// Kills the isolate.
+  ///
+  /// Starts by calling [close], but if that doesn't cause the isolate to
+  /// shut down in a timely manner, as given by [timeout], it follows up
+  /// with [Isolate.kill], with increasing urgency if necessary.
+  ///
+  /// If [timeout] is a zero duration, it goes directly to the most urgent
+  /// kill.
+  ///
+  /// If the isolate is already dead, the returned future will not complete.
+  /// If that may be the case, use [Future.timeout] on the returned future
+  /// to take extra action after a while. Example:
+  ///
+  ///     var f = isolate.kill();
+  ///     f.then((_) => print('Dead')
+  ///      .timeout(new Duration(...), onTimeout: () => print('No response'));
+  Future kill({Duration timeout: const Duration(seconds: 1)}) {
+    Future onExit = singleResponseFuture(isolate.addOnExitListener);
+    if (Duration.ZERO == timeout) {
+      isolate.kill(priority: Isolate.IMMEDIATE);
+      return onExit;
+    } else {
+      // Try a more gentle shutdown sequence.
+      _commandPort.send(list1(_SHUTDOWN));
+      return onExit.timeout(timeout, onTimeout: () {
+        isolate.kill(priority: Isolate.IMMEDIATE);
+        return onExit;
+      });
+    }
+  }
+
+  /// Queries the isolate on whether it's alive.
+  ///
+  /// If the isolate is alive and responding to commands, the
+  /// returned future completes with `true`.
+  ///
+  /// If the other isolate is not alive (like after calling [kill]),
+  /// or doesn't answer within [timeout] for any other reason,
+  /// the returned future completes with `false`.
+  ///
+  /// Guaranteed to only complete after all previous sent isolate commands
+  /// (like pause and resume) have been handled.
+  /// Paused isolates do respond to ping requests.
+  Future<bool> ping({Duration timeout: const Duration(seconds: 1)}) {
+    var channel = new SingleResponseChannel(callback: _kTrue,
+                                            timeout: timeout,
+                                            timeoutValue: false);
+    isolate.ping(channel.port);
+    return channel.result;
+  }
+
+  static bool _kTrue(_) => true;
+
+  /// Pauses the isolate.
+  ///
+  /// While paused, no normal messages are processed, and calls to [run] will
+  /// be delayed until the isolate is resumed.
+  ///
+  /// Commands like [kill] and [ping] are still executed while the isolate is
+  /// paused.
+  ///
+  /// If [resumeCapability] is omitted, it defaults to the [isolate]'s
+  /// [Isolate.pauseCapability].
+  ///
+  /// Calling pause more than once with the same `resumeCapability`
+  /// has no further effect. Only a single call to [resume] is needed
+  /// to resume the isolate.
+  void pause([Capability resumeCapability]) {
+    if (resumeCapability == null) resumeCapability = isolate.pauseCapability;
+    isolate.pause(resumeCapability);
+  }
+
+  /// Resumes after a [pause].
+  ///
+  /// If [resumeCapability] is omitted, it defaults to the isolate's
+  /// [Isolate.pauseCapability].
+  ///
+  /// Even if `pause` has been called more than once with the same
+  /// `resumeCapability`, a single resume call with stop the pause.
+  void resume([Capability resumeCapability]) {
+    if (resumeCapability == null) resumeCapability = isolate.pauseCapability;
+    isolate.resume(resumeCapability);
+  }
+
+  /// Execute `function(argument)` in the isolate and return the result.
+  ///
+  /// Sends [function] and [argument] to the isolate, runs the call, and
+  /// returns the result, whether it returned a value or threw.
+  /// If the call returns a [Future], the final result of that future
+  /// will be returned.
+  ///
+  /// This works similar to the arguments to [Isolate.spawn], except that
+  /// it runs in the existing isolate and the return value is returned to
+  /// the caller.
+  ///
+  /// Example:
+  ///
+  ///     IsolateRunner iso = await IsolateRunner.spawn();
+  ///     try {
+  ///       return await iso.run(heavyComputation, argument);
+  ///     } finally {
+  ///       await iso.close();
+  ///     }
+  Future run(function(argument), argument, {Duration timeout, onTimeout()}) {
+    return singleResultFuture((SendPort port) {
+      _commandPort.send(list4(_RUN, function, argument, port));
+    }, timeout: timeout, onTimeout: onTimeout);
+  }
+
+  /// A broadcast stream of uncaught errors from the isolate.
+  ///
+  /// When listening on the stream, errors from the isolate will be reported
+  /// as errors in the stream. Be ready to handle the errors.
+  ///
+  /// The stream closes when the isolate shuts down.
+  Stream get errors {
+    StreamController controller;
+    RawReceivePort port;
+    void handleError(message) {
+      if (message == null) {
+        // Isolate shutdown.
+        port.close();
+        controller.close();
+      } else {
+        // Uncaught error.
+        String errorDescription = message[0];
+        String stackDescription = message[1];
+        var error = new RemoteError(errorDescription, stackDescription);
+        controller.addError(error, error.stackTrace);
+      }
+    }
+    controller = new StreamController.broadcast(
+        sync: true,
+        onListen: () {
+          port = new RawReceivePort(handleError);
+          isolate.addErrorListener(port.sendPort);
+          isolate.addOnExitListener(port.sendPort);
+        },
+        onCancel: () {
+          isolate.removeErrorListener(port.sendPort);
+          isolate.removeOnExitListener(port.sendPort);
+          port.close();
+          port = null;
+        });
+    return controller.stream;
+  }
+
+  /// Waits for the [isolate] to terminate.
+  ///
+  /// Completes the returned future when the isolate terminates.
+  ///
+  /// If the isolate has already stopped responding to commands,
+  /// the returned future will be completed after one second,
+  /// using [ping] to check if the isolate is still alive.
+  Future get onExit {
+    // TODO(lrn): Is there a way to see if an isolate is dead
+    // so we can close the receive port for this future?
+    if (_onExitFuture == null) {
+      var channel = new SingleResponseChannel();
+      isolate.addOnExitListener(channel.port);
+      _onExitFuture = channel.result;
+      ping().then((bool alive) {
+        if (!alive) {
+          channel.interrupt();
+          _onExitFuture = null;
+        }
+      });
+    }
+    return _onExitFuture;
+  }
+}
+
+/// The remote part of an [IsolateRunner].
+///
+/// The `IsolateRunner` sends commands to the controlled isolate through
+/// the `IsolateRunnerRemote` [commandPort].
+///
+/// Only use this class if you need to set up the isolate manually
+/// instead of relying on [IsolateRunner.spawn].
+class IsolateRunnerRemote {
+  final RawReceivePort _commandPort = new RawReceivePort();
+  IsolateRunnerRemote() {
+    _commandPort.handler = _handleCommand;
+  }
+
+  /// The command port that can be used to send commands to this remote.
+  ///
+  /// Use this as argument to [new IsolateRunner] if creating the link
+  /// manually, otherwise it's handled by [IsolateRunner.spawn].
+  SendPort get commandPort => _commandPort.sendPort;
+
+  static void _create(SendPort initPort) {
+    var remote = new IsolateRunnerRemote();
+    initPort.send(remote.commandPort);
+  }
+
+  void _handleCommand(List command) {
+    switch (command[0]) {
+      case _SHUTDOWN:
+        SendPort responsePort = command[1];
+        _commandPort.close();
+        responsePort.send(null);
+        return;
+      case _RUN:
+        Function function = command[1];
+        var argument = command[2];
+        SendPort responsePort = command[3];
+        sendFutureResult(new Future.sync(() => function(argument)),
+                         responsePort);
+        return;
+    }
+  }
+}