ScriptPromise implementation for V8 Promises

Source/bindings/v8/ScriptPromiseResolver.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 33 matching lines @@
 
 namespace WebCore {
 
 class ExecutionContext;
 
 // ScriptPromiseResolver is a class for performing operations on Promise
 // (resolve / reject) from C++ world.
 // ScriptPromiseResolver holds a PromiseResolver.
 // Here is a typical usage:
 //  1. Create a ScriptPromiseResolver.
-//  2. Pass the promise object of the holder to a JavaScript program
+//  2. Pass the associated promise object to a JavaScript program
 //     (such as XMLHttpRequest return value).
 //  3. Call resolve or reject when the operation completes or
 //     the operation fails respectively.
 //
 // Most methods including constructors must be called within a v8 context.
 // To use ScriptPromiseResolver out of a v8 context the caller must
 // enter a v8 context, for example by using ScriptScope and ScriptState.
 //
 // To prevent memory leaks, you should release the reference manually
 // by calling resolve or reject.
 // Destroying the object will also release the reference.
-//
+// Note that ScriptPromiseResolver::promise returns an empty value when the
+// resolver is already resolved or rejected. If you want to resolve a resolver
+// immediately and return the associated promise, you should get the promise
+// before resolving.
 class ScriptPromiseResolver : public RefCounted<ScriptPromiseResolver> {
     WTF_MAKE_NONCOPYABLE(ScriptPromiseResolver);
 public:
     static PassRefPtr<ScriptPromiseResolver> create(ExecutionContext*);
     static PassRefPtr<ScriptPromiseResolver> create(v8::Isolate*);
 
     // A ScriptPromiseResolver should be resolved / rejected before
     // its destruction.
     // A ScriptPromiseResolver can be destructed safely without
     // entering a v8 context.
     ~ScriptPromiseResolver();
 
-    // Return true if the promise object is in pending state.
-    bool isPending() const;
-
-    ScriptPromise promise()
-    {
-        ASSERT(m_promise.isolate()->InContext());
-        return m_promise;
-    }
+    // Returns the underlying Promise.
+    // Note that the underlying Promise is cleared when |resolve| or |reject|
+    // is called.
+    ScriptPromise promise();
 
     // To use following template methods, T must be a DOM class.
 
     // This method will be implemented by the code generator.
     template<typename T>
     void resolve(T* value, v8::Handle<v8::Object> creationContext) { resolve(toV8NoInline(value, creationContext, m_isolate)); }
     template<typename T>
     void reject(T* value, v8::Handle<v8::Object> creationContext) { reject(toV8NoInline(value, creationContext, m_isolate)); }
 
     template<typename T>
@@ skipping 37 matching lines @@
     void reject(ScriptValue);
 
 private:
     ScriptPromiseResolver(ExecutionContext*);
     ScriptPromiseResolver(v8::Isolate*);
 
     void resolve(v8::Handle<v8::Value>);
     void reject(v8::Handle<v8::Value>);
 
     v8::Isolate* m_isolate;
+    // Used when scriptPromiseOnV8Promise is disabled.
     ScriptPromise m_promise;
+    // Used when scriptPromiseOnV8Promise is enabled.
+    ScriptValue m_resolver;
 };
 
 template<typename T>
 void ScriptPromiseResolver::resolve(T* value, ExecutionContext* context)
 {
     ASSERT(m_isolate->InContext());
     v8::Handle<v8::Context> v8Context = toV8Context(context, DOMWrapperWorld::current(m_isolate));
     resolve(value, v8Context->Global());
 }
 
@@ skipping 16 matching lines @@
 void ScriptPromiseResolver::reject(T* value)
 {
     ASSERT(m_isolate->InContext());
     reject(value, v8::Object::New(m_isolate));
 }
 
 } // namespace WebCore
 
 
 #endif // ScriptPromiseResolver_h