Add 'startPaused' option to Isolate.spawn*.

Initial implementation of startPaused in dart2js.

R=floitsch@google.com

Review URL: https://codereview.chromium.org//163523003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@32722 260f80e4-7a28-3924-810f-c04153c831b5

runtime/lib/isolate_patch.dart

@@ -227,7 +227,8 @@ void _startIsolate(Function entryPoint, bool isSpawnUri) {
 
 patch class Isolate {
   /* patch */ static Future<Isolate> spawn(
-      void entryPoint(message), var message) {
+      void entryPoint(message), var message, { bool paused: false }) {
+    // `paused` isn't handled yet.
     try {
       // The VM will invoke [_startIsolate] with entryPoint as argument.
       SendPort controlPort = _spawnFunction(entryPoint);
@@ -246,7 +247,8 @@ patch class Isolate {
   }
 
   /* patch */ static Future<Isolate> spawnUri(
-      Uri uri, List<String> args, var message) {
+      Uri uri, List<String> args, var message, { bool paused: false }) {
+    // `paused` isn't handled yet.
     try {
       // The VM will invoke [_startIsolate] and not `main`.
       SendPort controlPort = _spawnUri(uri.toString());

sdk/lib/_internal/lib/isolate_helper.dart

@@ -264,7 +264,7 @@ class _IsolateContext implements IsolateContext {
 
   final Capability pauseCapability = new Capability();
 
-  // TODO(lrn): Store these in single "pausestate" object, so they don't take
+  // TODO(lrn): Store these in single "PauseState" object, so they don't take
   // up as much room when not pausing.
   bool isPaused = false;
   List<_IsolateEvent> delayedEvents = [];
@@ -279,6 +279,7 @@ class _IsolateContext implements IsolateContext {
     if (pauseTokens.add(resume) && !isPaused) {
       isPaused = true;
     }
+    _updateGlobalState();
   }
 
   void removePause(Capability resume) {
@@ -291,6 +292,7 @@ class _IsolateContext implements IsolateContext {
       }
       isPaused = false;
     }
+    _updateGlobalState();
   }
 
   /**
@@ -354,7 +356,7 @@ class _IsolateContext implements IsolateContext {
   }
 
   _updateGlobalState() {
-    if (ports.length - weakPorts.length > 0) {
+    if (ports.length - weakPorts.length > 0 || isPaused) {
       _globalState.isolates[id] = this; // indicate this isolate is active
     } else {
       _globalState.isolates.remove(id); // indicate this isolate is not active
@@ -592,10 +594,12 @@ class IsolateNatives {
         var args = msg['args'];
         var message = _deserializeMessage(msg['msg']);
         var isSpawnUri = msg['isSpawnUri'];
+        var startPaused = msg['startPaused'];
         var replyTo = _deserializeMessage(msg['replyTo']);
         var context = new _IsolateContext();
         _globalState.topEventLoop.enqueue(context, () {
-          _startIsolate(entryPoint, args, message, isSpawnUri, replyTo);
+          _startIsolate(entryPoint, args, message,
+                        isSpawnUri, startPaused, replyTo);
         }, 'worker-start');
         // Make sure we always have a current context in this worker.
         // TODO(7907): This is currently needed because we're using
@@ -609,7 +613,8 @@ class IsolateNatives {
       case 'spawn-worker':
         _spawnWorker(msg['functionName'], msg['uri'],
                      msg['args'], msg['msg'],
-                     msg['isSpawnUri'], msg['replyPort']);
+                     msg['isSpawnUri'], msg['startPaused'],
+                     msg['replyPort']);
         break;
       case 'message':
         SendPort port = msg['port'];
@@ -677,17 +682,24 @@ class IsolateNatives {
   }
 
   static Future<List> spawnFunction(void topLevelFunction(message),
-                                        message) {
+                                    var message,
+                                    bool startPaused) {
     final name = _getJSFunctionName(topLevelFunction);
     if (name == null) {
       throw new UnsupportedError(
           "only top-level functions can be spawned.");
     }
-    return spawn(name, null, null, message, false, false);
+    bool isLight = false;
+    bool isSpawnUri = false;
+    return spawn(name, null, null, message, isLight, isSpawnUri, startPaused);
   }
 
-  static Future<List> spawnUri(Uri uri, List<String> args, message) {
-    return spawn(null, uri.toString(), args, message, false, true);
+  static Future<List> spawnUri(Uri uri, List<String> args, var message,
+                               bool startPaused) {
+    bool isLight = false;
+    bool isSpawnUri = true;
+    return spawn(null, uri.toString(), args, message,
+                 isLight, isSpawnUri, startPaused);
   }
 
   // TODO(sigmund): clean up above, after we make the new API the default:
@@ -695,7 +707,7 @@ class IsolateNatives {
   /// If [uri] is `null` it is replaced with the current script.
   static Future<List> spawn(String functionName, String uri,
                             List<String> args, message,
-                            bool isLight, bool isSpawnUri) {
+                            bool isLight, bool isSpawnUri, bool startPaused) {
     // Assume that the compiled version of the Dart file lives just next to the
     // dart file.
     // TODO(floitsch): support precompiled version of dart2js output.
@@ -710,10 +722,12 @@ class IsolateNatives {
     SendPort signalReply = port.sendPort;
 
     if (_globalState.useWorkers && !isLight) {
-      _startWorker(functionName, uri, args, message, isSpawnUri, signalReply);
+      _startWorker(functionName, uri, args, message, isSpawnUri, startPaused,
+                   signalReply);
     } else {
       _startNonWorker(
-          functionName, uri, args, message, isSpawnUri, signalReply);
+          functionName, uri, args, message, isSpawnUri, startPaused,
+          signalReply);
     }
     return result;
   }
@@ -722,6 +736,7 @@ class IsolateNatives {
       String functionName, String uri,
       List<String> args, message,
       bool isSpawnUri,
+      bool startPaused,
       SendPort replyPort) {
     if (_globalState.isWorker) {
       _globalState.mainManager.postMessage(_serializeMessage({
@@ -731,16 +746,19 @@ class IsolateNatives {
           'msg': message,
           'uri': uri,
           'isSpawnUri': isSpawnUri,
+          'startPaused': startPaused,
           'replyPort': replyPort}));
     } else {
-      _spawnWorker(functionName, uri, args, message, isSpawnUri, replyPort);
+      _spawnWorker(functionName, uri, args, message,
+                   isSpawnUri, startPaused, replyPort);
     }
   }
 
   static void _startNonWorker(
       String functionName, String uri,
-      List<String> args, message,
+      List<String> args, var message,
       bool isSpawnUri,
+      bool startPaused,
       SendPort replyPort) {
     // TODO(eub): support IE9 using an iframe -- Dart issue 1702.
     if (uri != null) {
@@ -749,13 +767,14 @@ class IsolateNatives {
     }
     _globalState.topEventLoop.enqueue(new _IsolateContext(), () {
       final func = _getJSFunctionFromName(functionName);
-      _startIsolate(func, args, message, isSpawnUri, replyPort);
+      _startIsolate(func, args, message, isSpawnUri, startPaused, replyPort);
     }, 'nonworker start');
   }
 
   static void _startIsolate(Function topLevel,
                             List<String> args, message,
                             bool isSpawnUri,
+                            bool startPaused,
                             SendPort replyTo) {
     _IsolateContext context = JS_CURRENT_ISOLATE_CONTEXT();
     Primitives.initializeStatics(context.id);
@@ -763,6 +782,8 @@ class IsolateNatives {
     replyTo.send([_SPAWNED_SIGNAL,
                   context.controlPort.sendPort,
                   context.pauseCapability]);
+
+    void runStartFunction() {
       if (!isSpawnUri) {
         topLevel(message);
       } else if (topLevel is _MainFunctionArgsMessage) {
@@ -774,6 +795,15 @@ class IsolateNatives {
       }
     }
 
+    if (startPaused) {
+      context.addPause(context.pauseCapability, context.pauseCapability);
+      _globalState.topEventLoop.enqueue(context, runStartFunction,
+                                        'start isolate');
+    } else {
+      runStartFunction();
+    }
+  }
+
   /**
    * Spawns an isolate in a worker. [factoryName] is the Javascript constructor
    * name for the isolate entry point class.
@@ -781,6 +811,7 @@ class IsolateNatives {
   static void _spawnWorker(functionName, String uri,
                            List<String> args, message,
                            bool isSpawnUri,
+                           bool startPaused,
                            SendPort replyPort) {
     if (uri == null) uri = thisScript;
     final worker = JS('var', 'new Worker(#)', uri);
@@ -805,6 +836,7 @@ class IsolateNatives {
         'args': args,
         'msg': _serializeMessage(message),
         'isSpawnUri': isSpawnUri,
+        'startPaused': startPaused,
         'functionName': functionName }));
   }
 }
@@ -844,7 +876,6 @@ class _NativeJsSendPort extends _BaseSendPort implements SendPort {
     final isolate = _globalState.isolates[_isolateId];
     if (isolate == null) return;
     if (_receivePort._isClosed) return;
-
     // We force serialization/deserialization as a simple way to ensure
     // isolate communication restrictions are respected between isolates that
     // live in the same worker. [_NativeJsSendPort] delivers both messages

sdk/lib/_internal/lib/isolate_patch.dart

@@ -12,9 +12,10 @@ import 'dart:_isolate_helper' show CapabilityImpl,
                                    RawReceivePortImpl;
 
 patch class Isolate {
-  patch static Future<Isolate> spawn(void entryPoint(message), var message) {
+  patch static Future<Isolate> spawn(void entryPoint(message), var message,
+                                     { bool paused: false }) {
     try {
-      return IsolateNatives.spawnFunction(entryPoint, message)
+      return IsolateNatives.spawnFunction(entryPoint, message, paused)
           .then((msg) => new Isolate._fromControlPort(msg[1], msg[2]));
     } catch (e, st) {
       return new Future<Isolate>.error(e, st);
@@ -22,7 +23,7 @@ patch class Isolate {
   }
 
   patch static Future<Isolate> spawnUri(
-      Uri uri, List<String> args, var message) {
+      Uri uri, List<String> args, var message, { bool paused: false }) {
     try {
       if (args is List<String>) {
         for (int i = 0; i < args.length; i++) {
@@ -33,7 +34,7 @@ patch class Isolate {
       } else if (args != null) {
         throw new ArgumentError("Args must be a list of Strings $args");
       }
-      return IsolateNatives.spawnUri(uri, args, message)
+      return IsolateNatives.spawnUri(uri, args, message, paused)
           .then((msg) => new Isolate._fromControlPort(msg[1], msg[2]));
     } catch (e, st) {
       return new Future<Isolate>.error(e, st);

sdk/lib/isolate/isolate.dart

@@ -58,7 +58,8 @@ class Isolate {
    * 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> spawn(void entryPoint(message), var message);
+  external static Future<Isolate> spawn(void entryPoint(message), var message,
+                                        { bool paused: false });
 
   /**
    * Creates and spawns an isolate that runs the code from the library with
@@ -80,7 +81,7 @@ class Isolate {
    * spawning succeeded. It will complete with an error otherwise.
    */
   external static Future<Isolate> spawnUri(
-      Uri uri, List<String> args, var message);
+      Uri uri, List<String> args, var message, { bool paused: false });
 
 
   /**

tests/isolate/isolate.status

@@ -12,6 +12,7 @@ isolate_throws_test/01: Skip # Issue 12587
 compile_time_error_test/01: Skip # Issue 12587
 capability_test: Fail   # Not implemented yet
 pause_test: Fail        # Not implemented yet
+start_paused_test: Fail # Not implemented yet
 
 [ $compiler == dart2js && $jscl ]
 browser/*: SkipByDesign  # Browser specific tests

tests/isolate/start_paused_test.dart

@@ -0,0 +1,81 @@
+// Copyright (c) 2014, 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 start_paused_test;
+
+import "dart:isolate";
+import "package:expect/expect.dart";
+import "package:async_helper/async_helper.dart";
+
+void isomain(SendPort p) {
+  p.send("DONE");
+}
+
+void notyet(_) {
+  throw "NOT YET";
+}
+
+void main() {
+  asyncStart();
+  test1();
+  test2();
+  asyncEnd();
+}
+
+void test1() {
+  // Test that a paused isolate doesn't send events.
+  // We start two isolates, one paused and one not.
+  // The unpaused one must send an event, after which
+  // we resume that paused isolate, and expect the second event.
+  // This is not a guaranteed test, since it can succeede even if the
+  // paused isolate isn't really paused.
+  // However, it must never fail, since that would mean that a paused
+  // isolate sends a message.
+  asyncStart();
+  RawReceivePort p1 = new RawReceivePort(notyet);
+  Isolate.spawn(isomain, p1.sendPort, paused: true)
+         .then((isolate) {
+    RawReceivePort p2;
+    p2 = new RawReceivePort((x) {
+      Expect.equals("DONE", x);
+      p2.close();
+      p1.handler = (x) {
+        Expect.equals("DONE", x);
+        p1.close();
+        asyncEnd();
+      };
+      isolate.resume(isolate.pauseCapability);
+    });
+    Isolate.spawn(isomain, p2.sendPort);
+  });
+}
+
+void test2() {
+  // Test that a paused isolate doesn't send events.
+  // Like the test above, except that we change the pause capability
+  // of the paused isolate by pausing it using another capability and
+  // then resuming the initial pause. This must not cause it to send
+  // a message before the second pause is resumed as well.
+  asyncStart();
+  RawReceivePort p1 = new RawReceivePort(notyet);
+  Isolate.spawn(isomain, p1.sendPort, paused: true)
+         .then((isolate) {
+    RawReceivePort p2;
+    Capability c2 = new Capability();
+    // Switch to another pause capability.
+    isolate.pause(c2);
+    isolate.resume(isolate.pauseCapability);
+    p2 = new RawReceivePort((x) {
+      Expect.equals("DONE", x);
+      p2.close();
+      p1.handler = (x) {
+        Expect.equals("DONE", x);
+        p1.close();
+        asyncEnd();
+      };
+      isolate.resume(c2);
+    });
+    Isolate.spawn(isomain, p2.sendPort);
+  });
+}