Add IsolateRunner as a helper around Isolate.

lib/src/functionref.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.
+
+/**
+ * Convert top-level or static functions to objects that can be sent to
+ * other isolates.
+ *
+ * This package is only needed until such functions can be sent directly
+ * through send-ports.
+ */
+library pkg.isolate.functionref;
+
+import "dart:mirrors";
+
+abstract class FunctionRef {
+  static FunctionRef from(Function function) {
+    var cm = reflect(function);
+    if (cm is ClosureMirror) {
+      MethodMirror fm = cm.function;
+      if (fm.isRegularMethod && fm.isStatic) {
+        Symbol functionName = fm.simpleName;
+        Symbol className;
+        DeclarationMirror owner = fm.owner;
+        if (owner is ClassMirror) {
+          className = owner.simpleName;
+          owner = owner.owner;
+        }
+        if (owner is LibraryMirror) {
+          LibraryMirror ownerLibrary = owner;
+          Uri libraryUri = ownerLibrary.uri;
+          return new _FunctionRef(libraryUri, className, functionName);
+        }
+      }
+      throw new ArgumentError.value(function, "function",
+                                    "Not a static or top-level function");
+    }
+    // It's a Function but not a closure, so it's a callable object.
+    return new _CallableObjectRef(function);
+  }
+
+  Function get function;
+}
+
+class _FunctionRef implements FunctionRef {
+  final Uri libraryUri;
+  final Symbol className;
+  final Symbol functionName;
+
+  _FunctionRef(this.libraryUri, this.className, this.functionName);
+
+  Function get function {
+    LibraryMirror lm = currentMirrorSystem().libraries[libraryUri];
+    if (lm != null) {
+      ObjectMirror owner = lm;
+      if (className != null) {
+        ClassMirror cm = lm.declarations[className];
+        owner = cm;
+      }
+      if (owner != null) {
+        ClosureMirror function = owner.getField(this.functionName);
+        if (function != null) return function.reflectee;
+      }
+    }
+    String functionName = MirrorSystem.getName(this.functionName);
+    String classQualifier = "";
+    if (this.className != null) {
+      classQualifier  = " in class ${MirrorSystem.getName(this.className)}";
+    }
+    throw new UnsupportedError(
+      "Function $functionName${classQualifier} not found in library $libraryUri"
+    );
+  }
+}
+
+class _CallableObjectRef implements FunctionRef {
+  final Function object;
+  _CallableObjectRef(this.object);
+  Function get function => object;
+}