Implement ScriptPromise and ScriptFunction

Source/bindings/v8/ScriptPromise.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
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * 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 ScriptPromise_h
+#define ScriptPromise_h
+
+#include "bindings/v8/ScopedPersistent.h"
+#include "bindings/v8/ScriptFunction.h"
+#include "bindings/v8/V8ScriptRunner.h"
+
+#include <v8.h>
+
+namespace WebCore {
+
+// ScriptPromise is a class for hooking into the then() chain for a
+// Promise from the C++ world.
+//
+// To use this, provide a subclass of ScriptFunction where the 'call'
+// method the function to pass to 'Promise.then'.
+//
+// class MyCallback : public ScriptFunction {
+// public:
+//   MyCallback(PassRefPtr<MyClass> reciever) : m_receiver(receiver) { }
+//   virtual ScriptValue call(ScriptValue scriptValue) {
+//     m_receiver->HaveValue(scriptValue.v8Value().As<v8::Integer>()->Value())
+//     return scriptValue;
+//   }
+//   int value() const { return m_value; }
+//
+// private:
+//   RefPtr<MyClass> m_receiver;
+// };
+//
+// void MyClass::saveValue(ScriptPromise* promise) {
+//   promise->then(adoptRef(new MyCallback(this)));
+// }
+//
+// void MyClass::HaveValue(int value) {
+//   .. deal with the value here.
+// }
+class ScriptPromise {
+public:
+    explicit ScriptPromise(ScriptValue promise)
+        : m_promise(promise.v8Value()) { }
+
+    bool then(PassRefPtr<ScriptFunction> prpFunction)
+    {
+        if (m_promise.isEmpty())
+            return false;
+        v8::Isolate* isolate = v8::Isolate::GetCurrent();
+        v8::Handle<v8::Value> promise = m_promise.newLocal(isolate);
+        if (!promise->IsObject())
+            return false;
+
+        v8::Handle<v8::Object> promiseObject = promise.As<v8::Object>();
+        v8::Handle<v8::Value> then = promiseObject->Get(v8::String::NewSymbol("then"));
+        if (then.IsEmpty() || !then->IsFunction())
+            return false;
+
+        RefPtr<ScriptFunction> function(prpFunction);
+        v8::Handle<v8::Value> argv[] = {
+            function->toV8(isolate)
+        };
+        m_result.set(isolate, V8ScriptRunner::callFunction(then.As<v8::Function>(), getScriptExecutionContext(), promiseObject, WTF_ARRAY_LENGTH(argv), argv));
+        return true;
+    }
+
+    ScriptValue ResultPromise() { return ScriptValue(m_result.newLocal(v8::Isolate::GetCurrent())); }
+
+private:
+    ScopedPersistent<v8::Value> m_promise;
+    ScopedPersistent<v8::Value> m_result;
+};
+
+} // namespace WebCore
+
+
+#endif // ScriptPromise_h