ServiceWorker: Keep the worker alive until FetchEvent.waitUntil settles

third_party/WebKit/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 "modules/serviceworkers/RespondWithObserver.h"
 
 #include "bindings/core/v8/ScriptFunction.h"
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptValue.h"
 #include "bindings/core/v8/V8Binding.h"
@@ skipping 127 matching lines @@
         m_observer = nullptr;
         return value;
     }
 
     Member<RespondWithObserver> m_observer;
     ResolveType m_resolveType;
 };
 
 RespondWithObserver::~RespondWithObserver() {}
 
-RespondWithObserver* RespondWithObserver::create(ExecutionContext* context, int eventID, const KURL& requestURL, WebURLRequest::FetchRequestMode requestMode, WebURLRequest::FrameType frameType, WebURLRequest::RequestContext requestContext)
+RespondWithObserver* RespondWithObserver::create(ExecutionContext* context, int eventID, const KURL& requestURL, WebURLRequest::FetchRequestMode requestMode, WebURLRequest::FrameType frameType, WebURLRequest::RequestContext requestContext, WaitUntilObserver* observer)
 {
-    return new RespondWithObserver(context, eventID, requestURL, requestMode, frameType, requestContext);
+    return new RespondWithObserver(context, eventID, requestURL, requestMode, frameType, requestContext, observer);
 }
 
 void RespondWithObserver::contextDestroyed()
 {
     ContextLifecycleObserver::contextDestroyed();
     m_state = Done;
+    if (m_observer) {
+        m_observer->decrementPendingActivity();

[falken, 2016/06/22 01:27:32]

Where is the incrementPendingActivity this balances out? Are we sure it's
correct to decrement here?

[shimazu, 2016/06/22 05:41:27]

m_observer is non-null only when respondWith is in-flight at this point 
because didDispatchEvent decrements the counter and clears m_observer if there
is no respondWith, so this might be not a problem. 

Anyway, I found another bug; there is an excess decrementPendingActivity at the
last of didDispatchEvent... I removed it.

+        m_observer.clear();
+    }
 }
 
 void RespondWithObserver::didDispatchEvent(DispatchEventResult dispatchResult)
 {
     ASSERT(getExecutionContext());
     if (m_state != Initial)
         return;
 
     if (dispatchResult != DispatchEventResult::NotCanceled) {
         responseWasRejected(WebServiceWorkerResponseErrorDefaultPrevented);
         return;
     }
 
-    ServiceWorkerGlobalScopeClient::from(getExecutionContext())->didHandleFetchEvent(m_eventID);
+    ServiceWorkerGlobalScopeClient::from(getExecutionContext())->respondToFetchEvent(m_eventID);
     m_state = Done;
+    m_observer->decrementPendingActivity();
+    m_observer.clear();
 }
 
 void RespondWithObserver::respondWith(ScriptState* scriptState, ScriptPromise scriptPromise, ExceptionState& exceptionState)
 {
     if (m_state != Initial) {
         exceptionState.throwDOMException(InvalidStateError, "The fetch event has already been responded to.");
         return;
     }
 
     m_state = Pending;
+    m_observer->incrementPendingActivity();
     scriptPromise.then(
         ThenFunction::createFunction(scriptState, this, ThenFunction::Fulfilled),
         ThenFunction::createFunction(scriptState, this, ThenFunction::Rejected));
 }
 
 void RespondWithObserver::responseWasRejected(WebServiceWorkerResponseError error)
 {
     ASSERT(getExecutionContext());
     getExecutionContext()->addConsoleMessage(ConsoleMessage::create(JSMessageSource, WarningMessageLevel, getMessageForResponseError(error, m_requestURL)));
 
     // The default value of WebServiceWorkerResponse's status is 0, which maps
     // to a network error.
     WebServiceWorkerResponse webResponse;
     webResponse.setError(error);
-    ServiceWorkerGlobalScopeClient::from(getExecutionContext())->didHandleFetchEvent(m_eventID, webResponse);
+    ServiceWorkerGlobalScopeClient::from(getExecutionContext())->respondToFetchEvent(m_eventID, webResponse);
     m_state = Done;
+    m_observer->decrementPendingActivity();
+    m_observer.clear();
 }
 
 void RespondWithObserver::responseWasFulfilled(const ScriptValue& value)
 {
     ASSERT(getExecutionContext());
     if (!V8Response::hasInstance(value.v8Value(), toIsolate(getExecutionContext()))) {
         responseWasRejected(WebServiceWorkerResponseErrorNoV8Instance);
         return;
     }
     Response* response = V8Response::toImplWithTypeCheck(toIsolate(getExecutionContext()), value.v8Value());
@@ skipping 42 matching lines @@
     if (buffer) {
         RefPtr<BlobDataHandle> blobDataHandle = buffer->drainAsBlobDataHandle(FetchDataConsumerHandle::Reader::AllowBlobWithInvalidSize);
         if (blobDataHandle) {
             webResponse.setBlobDataHandle(blobDataHandle);
         } else {
             Stream* outStream = Stream::create(getExecutionContext(), "");
             webResponse.setStreamURL(outStream->url());
             buffer->startLoading(FetchDataLoader::createLoaderAsStream(outStream), new NoopLoaderClient);
         }
     }
-    ServiceWorkerGlobalScopeClient::from(getExecutionContext())->didHandleFetchEvent(m_eventID, webResponse);
+    ServiceWorkerGlobalScopeClient::from(getExecutionContext())->respondToFetchEvent(m_eventID, webResponse);
     m_state = Done;
+    m_observer->decrementPendingActivity();
+    m_observer.clear();
 }
 
-RespondWithObserver::RespondWithObserver(ExecutionContext* context, int eventID, const KURL& requestURL, WebURLRequest::FetchRequestMode requestMode, WebURLRequest::FrameType frameType, WebURLRequest::RequestContext requestContext)
+RespondWithObserver::RespondWithObserver(ExecutionContext* context, int eventID, const KURL& requestURL, WebURLRequest::FetchRequestMode requestMode, WebURLRequest::FrameType frameType, WebURLRequest::RequestContext requestContext, WaitUntilObserver* observer)
     : ContextLifecycleObserver(context)
     , m_eventID(eventID)
     , m_requestURL(requestURL)
     , m_requestMode(requestMode)
     , m_frameType(frameType)
     , m_requestContext(requestContext)
     , m_state(Initial)
+    , m_observer(observer)
 {
 }
 
 DEFINE_TRACE(RespondWithObserver)
 {
+    visitor->trace(m_observer);
     ContextLifecycleObserver::trace(visitor);
 }
 
 } // namespace blink