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:$message"); }
+Function createFuncToplevel() => (p, m) { p.send(m); };
+class C {
+  Function initializer;
+  Function body;
+  C() : initializer = ((p, m) { throw "initializer"; }) {
+    body = (p, m) { throw "body"; };
+  }
+  static void staticFunc(port, message) { port.send("static:$message"); }
+  static Function createFuncStatic() => (p, m) { throw "static expr"; };
+  void instanceMethod(p, m) { throw "instanceMethod"; }
+  Function createFuncMember() => (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.instanceMethod);
+  testUnsendable("static context expression", createFuncToplevel());
+  testUnsendable("static context expression", C.createFuncStatic());
+  testUnsendable("initializer context expression", c.initializer);
+  testUnsendable("constructor context expression", c.body);
+  testUnsendable("instance method context expression", c.createFuncMember());
+
+  // The result of `toplevel.call` and `staticFunc.call` may or may not be
+  // identical to `toplevel` and `staticFunc` respectively. If they are not
+  // equal, they may or may not be considered toplevel/static functions anyway,
+  // and therefore sendable. The VM and dart2js curretnly disagrees on whether
+  // `toplevel` and `toplevel.call` are identical, both allow them to be sent.
+  // If this is ever specified to something else, use:
+  //     testUnsendable("toplevel.call", toplevel.call);
+  //     testUnsendable("static.call", C.staticFunc.call);
+  // instead.
+  // These two tests should be considered canaries for accidental behavior
+  // change rather than requirements.
+  testSendable("toplevel", toplevel.call);
+  testSendable("static", C.staticFunc.call);
+
+  // Callable objects are sendable if general objects are (VM yes, dart2js no).
+  // It's unspecified whether arbitrary objects can be sent. If it is specified,
+  // add a test that `new Callable()` is either sendable or unsendable.
+
+  // The call method of a callable object is a closure holding the object,
+  // not a top-level or static function, so it should be blocked, just as
+  // a normal method.
+  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.
+SendPort 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.
+SendPort 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(() {                /// 01: ok
+    noReply.sendPort.send(func);    /// 01: continued
+  }, null, "send direct");          /// 01: continued
+  Expect.throws(() {                /// 01: continued
+    noReply.sendPort.send([func]);  /// 01: continued
+  }, null, "send wrapped");         /// 01: continued
+  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]);
+}