Allow sending static/top-level functions through ports and as isolate

tests/isolate/function_send_test.dart

+// 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.
+
+import "dart:isolate";
+import "dart:async";
+import "package:expect/expect.dart";
+import "package:async_helper/async_helper.dart";
+
+void toplevel(port, message) { port.send("toplevel:$message"); }
+void mkToplevelFunc() => (p, m) { p.send(m); };

[floitsch, 2014/09/19 19:52:45]

mkFuncToplevel
or
funcGeneratorToplevel

[Lasse Reichstein Nielsen, 2014/09/23 07:25:07]

I'll go for createFuncToplevel.

+class C {
+  Function initializer;
+  Function body;
+  C() : initializer = ((p, m) { throw "initializer"; }) {
+    body = (p, m) { throw "body"; };
+  }
+  static void staticFunc(port, message) { port.send("static:$message"); }
+  static Function mkStaticFunc() => (p, m) { throw "static expr"; };
+  void member(p, m) { throw "member"; }
+  void mkFunc() => (p, m) { throw "instance expr"; };
+  void call(n, p) { throw "C"; }
+}
+
+class Callable {
+  void call(p, m) { p.send(["callable", m]); }
+}
+
+
+void main() {
+  asyncStart();
+
+  // Sendables are top-level functions and static functions only.
+  testSendable("toplevel", toplevel);
+  testSendable("static", C.staticFunc);
+
+  // Unsendables are any closure - instance methods or function expression.
+  var c = new C();
+  testUnsendable("instance method", c.member);
+  testUnsendable("static context expression", mkToplevelFunc());
+  testUnsendable("static context expression", C.mkStaticFunc());
+  testUnsendable("initializer context expression", c.initializer);
+  testUnsendable("constructor context expression", c.body);
+  testUnsendable("instance method context expression", c.mkFunc());
+
+  // Actually allowed. Identical in VM, different, but still static, in dart2js.

[floitsch, 2014/09/19 19:52:45]

If it's allowed, why is it commented?

[Lasse Reichstein Nielsen, 2014/09/23 07:25:07]

I can't say whether it should be allowed or not, and the spec isn't helping.
I would have expected it to not work, but it turns out that it does.

I'll make the test match the current behavior and just make a comment saying
that it's unknown whether toplevel.call is equal to or identical to toplevel,
and whether it should be sendable if not identical.

+  // testUnsendable("toplevel.call closure", toplevel.call);
+  // testUnsendable("static.call closure", C.staticFunc.call);
+
+  // Callable objects are sendable if general objects are (VM yes, dart2js no).
+  //testSendable("callable object", new Callable());    /// 01: ok

[floitsch, 2014/09/19 19:52:45]

Why is it commented?
Especially with "/// 01: ok".

[Lasse Reichstein Nielsen, 2014/09/23 07:25:07]

Again I can't decide on whether it should be one or the other, and since the VM
will likely allow sending any object, including callable objects, and dart2js
will not, there is no clear answer.

+  testUnsendable("callable object", new Callable());    /// 02: ok

[floitsch, 2014/09/19 19:52:45]

That looks like the same as above...

[Lasse Reichstein Nielsen, 2014/09/23 07:25:07]

This one is test*Un*sendablem the one above is testSendable.

Neither is a hard requirement, so I'll just leave it out until the time when we
actually define what can be sent to which other isolates.

+  testUnsendable("callable object", new Callable().call);
+  asyncEnd();
+  return;
+}
+
+// Create a receive port that expects exactly one message.
+// Pass the message to `callback` and return the sendPort.
+void singleMessagePort(callback) {
+  var p;
+  p = new RawReceivePort((v) { p.close(); callback(v); });
+  return p.sendPort;
+}
+
+// A singleMessagePort that expects the message to be a specific value.
+void expectMessagePort(message) {
+  asyncStart();
+  return singleMessagePort((v) {
+    Expect.equals(message, v);
+    asyncEnd();
+  });
+}
+
+void testSendable(name, func) {
+  // Function as spawn message.
+  Isolate.spawn(callFunc, [func, expectMessagePort("$name:spawn"), "spawn"]);
+
+  // Send function to same isolate.
+  var reply = expectMessagePort("$name:direct");
+  singleMessagePort(callFunc).send([func, reply, "direct"]);
+
+  // Send function to other isolate, call it there.
+  reply = expectMessagePort("$name:other isolate");
+  callPort().then((p) {
+    p.send([func, reply, "other isolate"]);
+  });
+
+  // Round-trip function trough other isolate.
+  echoPort((roundtripFunc) {
+    Expect.identical(func, roundtripFunc, "$name:send through isolate");
+  }).then((port) { port.send(func); });
+}
+
+// Creates a new isolate and a pair of ports that expect a single message
+// to be sent to the other isolate and back to the callback function.
+Future<SendPort> echoPort(callback(value)) {
+  Completer completer = new Completer<SendPort>();
+  SendPort replyPort = singleMessagePort(callback);
+  RawReceivePort initPort;
+  initPort = new RawReceivePort((p) {
+    completer.complete(p);
+    initPort.close();
+  });
+  return Isolate.spawn(_echo, [replyPort, initPort.sendPort])
+                .then((isolate) => completer.future);
+}
+
+void _echo(msg) {
+  var replyPort = msg[0];
+  RawReceivePort requestPort;
+  requestPort = new RawReceivePort((msg) {
+    replyPort.send(msg);
+    requestPort.close();  // Single echo only.
+  });
+  msg[1].send(requestPort.sendPort);
+}
+
+// Creates other isolate that waits for a single message, `msg`, on the returned
+// port, and executes it as `msg[0](msg[1],msg[2])` in the other isolate.
+Future<SendPort> callPort() {
+  Completer completer = new Completer<SendPort>();
+  SendPort initPort = singleMessagePort(completer.complete);
+  return Isolate.spawn(_call, initPort)
+                .then((_) => completer.future);
+}
+
+void _call(initPort) {
+  initPort.send(singleMessagePort(callFunc));
+}
+  // Expect.throws(() {
+  //   noReply.sendPort.send([func]);
+  // }, null, "send wrapped");
+
+
+void testUnsendable(name, func) {
+  asyncStart();
+  Isolate.spawn(nop, func).then((v) => throw "allowed spawn direct?",
+                                onError: (e,s){ asyncEnd(); });
+  asyncStart();
+  Isolate.spawn(nop, [func]).then((v) => throw "allowed spawn wrapped?",
+                                  onError: (e,s){ asyncEnd(); });
+
+  asyncStart();
+  var noReply = new RawReceivePort((_) { throw "Unexpected message: $_"; });
+  // Currently succeedes incorrectly in dart2js.
+  // Expect.throws(() {
+  //   noReply.sendPort.send(func);
+  // }, null, "send direct");
+  // Expect.throws(() {
+  //   noReply.sendPort.send([func]);
+  // }, null, "send wrapped");
+  scheduleMicrotask(() {
+    noReply.close();
+    asyncEnd();
+  });
+
+  // Try sending through other isolate.
+  asyncStart();
+  echoPort((_) => throw "unreachable")
+    .then((p) => p.send(func))
+    .then((p) => throw "unreachable 2",
+          onError: (e, s) {asyncEnd();});
+}
+
+void nop(_) {}
+
+void callFunc(message) {
+  message[0](message[1], message[2]);
+}