Start to implement FetchEvent for ServiceWorker

Source/modules/serviceworkers/RespondWithObserver.cpp

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "config.h"
+#include "modules/serviceworkers/RespondWithObserver.h"
+
+#include "V8Response.h"
+#include "bindings/v8/ScriptFunction.h"
+#include "bindings/v8/ScriptPromise.h"
+#include "bindings/v8/ScriptValue.h"
+#include "bindings/v8/V8Binding.h"
+#include "core/dom/ExecutionContext.h"
+#include "modules/serviceworkers/ServiceWorkerGlobalScopeClient.h"
+#include "wtf/Assertions.h"
+#include "wtf/RefPtr.h"
+
+namespace WebCore {
+
+class RespondWithObserver::ThenFunction FINAL : public ScriptFunction {
+public:
+    enum ResolveType {
+        Fulfilled,
+        Rejected,
+    };

[kinuko, 2014/02/26 05:42:49]

(these promise-waiter functions could be probably generalized a bit further..?)

[falken, 2014/02/27 06:45:09]

Yes, this copied WaitUntilObserver. Let me do a refactoring in a future patch.

+
+    static PassOwnPtr<ScriptFunction> create(PassRefPtr<RespondWithObserver> observer, ResolveType type)
+    {
+        return adoptPtr(new ThenFunction(toIsolate(observer->executionContext()), observer, type));
+    }
+
+private:
+    ThenFunction(v8::Isolate* isolate, PassRefPtr<RespondWithObserver> observer, ResolveType type)
+        : ScriptFunction(isolate)
+        , m_observer(observer)
+        , m_resolveType(type)
+    {
+    }
+
+    virtual ScriptValue call(ScriptValue value) OVERRIDE
+    {
+        ASSERT(m_observer);
+        ASSERT(m_resolveType == Fulfilled || m_resolveType == Rejected);
+        if (m_resolveType == Rejected)
+            m_observer->responseWasRejected();
+        else
+            m_observer->responseWasFulfilled(value);
+        m_observer = nullptr;
+        return value;
+    }
+
+    RefPtr<RespondWithObserver> m_observer;
+    ResolveType m_resolveType;
+};
+
+PassRefPtr<RespondWithObserver> RespondWithObserver::create(ExecutionContext* context, int eventID)
+{
+    return adoptRef(new RespondWithObserver(context, eventID));
+}
+
+RespondWithObserver::~RespondWithObserver()
+{
+    ASSERT(m_state == Done);
+}
+
+void RespondWithObserver::didDispatchEvent()
+{
+    if (m_state == Initial)
+        sendResponse(nullptr);
+}
+
+void RespondWithObserver::respondWith(const ScriptValue& value)
+{
+    if (m_state != Initial)
+        return;
+
+    m_state = Pending;
+    ScriptPromise(value).then(
+        ThenFunction::create(this, ThenFunction::Fulfilled),
+        ThenFunction::create(this, ThenFunction::Rejected));
+}
+
+void RespondWithObserver::sendResponse(PassRefPtr<Response> response)
+{

[kinuko, 2014/02/26 05:42:49]

Shouldn't we check executionContext() is non-null here? (If not we wouldn't need
to inherit from LifecycleObserver)

[falken, 2014/02/27 06:45:09]

Oops, right. I guess this happens if the SW context dies before the respondWith
Promise is settled, or it died right before didDispatchEvent.

Fixed to be aware of destroyed executionContext.

+    ServiceWorkerGlobalScopeClient::from(executionContext())->didHandleFetchEvent(m_eventID, response);
+    m_state = Done;
+    observeContext(0);

[kinuko, 2014/02/26 05:42:49]

I don't think this is necessary

[falken, 2014/02/27 06:45:09]

Done.

+}
+
+void RespondWithObserver::responseWasRejected()
+{
+    // FIXME: Throw a NetworkError to service worker's execution context.
+    sendResponse(nullptr);
+}
+
+void RespondWithObserver::responseWasFulfilled(const ScriptValue& value)
+{
+    if (!V8Response::hasInstance(value.v8Value(), toIsolate(executionContext()))) {
+        responseWasRejected();
+        return;
+    }
+    v8::Handle<v8::Object> object = v8::Handle<v8::Object>::Cast(value.v8Value());
+    sendResponse(V8Response::toNative(object));
+}
+
+RespondWithObserver::RespondWithObserver(ExecutionContext* context, int eventID)
+    : ContextLifecycleObserver(context)
+    , m_eventID(eventID)
+    , m_state(Initial)
+{
+}
+
+} // namespace WebCore