Support general serializing of functions between JS and Dart

client/dart.js

 // 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.
 
 // Bootstrap support for Dart scripts on the page as this script.
 if (navigator.webkitStartDart) {
   if (!navigator.webkitStartDart()) {
     document.body.innerHTML = 'This build has expired.  Please download a new Dartium at http://www.dartlang.org/dartium/index.html';
   }
 } else {
@@ skipping 28 matching lines @@
 // ---------------------------------------------------------------------------
 function SendPortSync() {
 }
 
 function ReceivePortSync() {
   this.id = ReceivePortSync.id++;
   ReceivePortSync.map[this.id] = this;
 }
 
 (function() {
+  // Track proxied functions.
+  // TODO: Fix leaks, particularly in dart2js case.
+  var functionRefMap = {};
+
+  var nextFunctionRefId = 0;
+
+  function functionRefDispatch(message) {
+    var id = message[0];
+    var args = message[1];
+    var f = functionRefMap[id];
+    // TODO: Should we capture this automatically?
+    return f.apply(null, args);
+  }
+
+  var functionRefPort = null;
+
+  function makeFunctionRef(f) {
+    if (functionRefPort == null) {
+      var port = new ReceivePortSync();
+      port.receive(functionRefDispatch);
+      functionRefPort = port.toSendPort();
+    }
+    var ref = 'func-ref-' + (nextFunctionRefId++);
+    functionRefMap[ref] = f;
+    return ref;
+  }
+
   function serialize(message) {
     var visited = [];
     function checkedSerialization(obj, serializer) {
       // Implementation detail: for now use linear search.
       // Another option is expando, but it may prohibit
       // VM optimizations (like putting object into slow mode
       // on property deletion.)
       var id = visited.indexOf(obj);
       if (id != -1) return [ 'ref', id ];
       var id = visited.length;
@@ skipping 13 matching lines @@
           var values = new Array(message.length);
           for (var i = 0; i < message.length; i++) {
             values[i] = doSerialize(message[i]);
           }
           return [ 'list', id, values ];
         });
       } else if (message instanceof LocalSendPortSync) {
         return [ 'sendport', 'nativejs', message.receivePort.id ];
       } else if (message instanceof DartSendPortSync) {
         return [ 'sendport', 'dart', message.isolateId, message.portId ];
+      } else if (message instanceof Function) {
+        return [ 'funcref', makeFunctionRef(message),
+                 doSerialize(functionRefPort) ];
       } else {
         return checkedSerialization(message, function(id) {
           var keys = Object.getOwnPropertyNames(message);
           var values = new Array(keys.length);
           for (var i = 0; i < keys.length; i++) {
             values[i] = doSerialize(message[keys[i]]);
           }
           return [ 'map', id, keys, values ];
         });
       }
@@ skipping 152 matching lines @@
   }
 
   // Leaking implementation.
   // TODO: provide proper, backend-specific implementation.
   function _makeFunctionFromRef(ref, sendPort) {
     return function() {
       return sendPort.callSync([ref, Array.prototype.slice.call(arguments)]);
     }
   }
 })();