Implement ScriptPromise and ScriptFunction

Source/bindings/v8/ScriptFunction.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 10 matching lines @@
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef LayerRect_h
-#define LayerRect_h
+#ifndef ScriptFunction_h
+#define ScriptFunction_h
 
-#include "core/dom/ClientRect.h"
-
-#include "wtf/PassRefPtr.h"
+#include "bindings/v8/GarbageCollected.h"
+#include "bindings/v8/ScriptValue.h"
+#include "bindings/v8/V8Binding.h"
 #include "wtf/RefCounted.h"
-#include "wtf/RefPtr.h"
+#include <v8.h>
 
 namespace WebCore {
 
-class Node;
+// This class allows C++ to be passed as a v8::Function. To use it:
+// 1. Inherit from ScriptFunction and override call().
+// 2. toV8() will return a v8::Function that, when called, will call
+//    the overridden call() method.
+//
+// This exists primarily to support ScriptPromise::then().
+class ScriptFunction : public RefCounted<ScriptFunction> {
+public:
+    ScriptFunction() { }
 
-class LayerRect : public RefCounted<LayerRect> {
-public:
-    static PassRefPtr<LayerRect> create(PassRefPtr<Node> node, PassRefPtr<ClientRect> rect)
+    // override this
+    virtual ScriptValue call(ScriptValue arg) { return ScriptValue(); }
+
+    v8::Handle<v8::Function> toV8()
     {
-        return adoptRef(new LayerRect(node, rect));
+        v8::Isolate* isolate = v8::Isolate::GetCurrent();
+        if (m_function.isEmpty()) {
+            ref();

[abarth-chromium, 2013/08/15 00:23:54]

You should be able to encapsulate all this nastiness in GarbageCollected.  In
fact, you should be able to avoid using RefCounted as a base class entirely. 
When the v8 object dies, you can just delete |this| because it's been collected
by the GC.

+            m_function.set(isolate, v8::FunctionTemplate::New(&callCallback, v8::External::New(this))->GetFunction());
+        }
+        return m_function.newLocal(isolate);
     }
 
-    Node* layerRootNode() const { return m_layerRootNode.get(); }
-    ClientRect* layerRelativeRect() const { return m_rect.get(); }
+protected:
+    virtual ~ScriptFunction() { }
 
 private:
-    LayerRect(PassRefPtr<Node> node, PassRefPtr<ClientRect> rect)
-        : m_layerRootNode(node)
-        , m_rect(rect)
+    static void callCallback(const v8::FunctionCallbackInfo<v8::Value>& args)
     {
+        v8::Isolate* isolate = args.GetIsolate();
+        ASSERT(!args.Data().IsEmpty());
+        RefPtr<ScriptFunction> function = adoptRef(static_cast<ScriptFunction*>(args.Data().As<v8::External>()->Value()));
+        v8::Local<v8::Value> value = args.Length() > 0 ? (args[0]) : v8::Local<v8::Value>(v8::Undefined(isolate));
+
+        ScriptValue result = function->call(ScriptValue(value));
+        v8SetReturnValue(args, result.v8Value());
     }
 
-    RefPtr<Node> m_layerRootNode;
-    RefPtr<ClientRect> m_rect;
+    GarbageCollected<v8::Function> m_function;

[abarth-chromium, 2013/08/15 00:35:15]

ScriptFunction need to hold a ScopedPeristent<v8::Function>.  That v8::Function
will then hold the v8::External.  The GarbageCollected base class then holds a
weak handle to the v8::External to detect when it's time to delete the void*
stored in the v8::External.

+    friend class RefCounted<ScriptFunction>;
 };
 
 } // namespace WebCore
 
 #endif