rAc: make requestAutocomplete() return a promise.

Source/core/html/HTMLFormElement.cpp

Index: Source/core/html/HTMLFormElement.cpp
diff --git a/Source/core/html/HTMLFormElement.cpp b/Source/core/html/HTMLFormElement.cpp
index cfb51cacf91998afe5f5dc2cbdac2188f85e7699..99561fcc63ff24250a7f4863ae1c7cbd6bb893ec 100644
--- a/Source/core/html/HTMLFormElement.cpp
+++ b/Source/core/html/HTMLFormElement.cpp
@@ -28,8 +28,11 @@
 #include <limits>
 #include "HTMLNames.h"
 #include "bindings/v8/Dictionary.h"
+#include "bindings/v8/NewScriptState.h"
 #include "bindings/v8/ScriptController.h"
 #include "bindings/v8/ScriptEventListener.h"
+#include "bindings/v8/ScriptPromiseResolver.h"
+#include "bindings/v8/ScriptValue.h"
 #include "core/dom/Attribute.h"
 #include "core/dom/Document.h"
 #include "core/dom/ElementTraversal.h"
@@ -85,6 +88,67 @@ HTMLFormElement::~HTMLFormElement()
     document().formController().willDeleteForm(this);
 }
 
+class AutocompleteRequest {
+public:
+    static PassOwnPtr<AutocompleteRequest> create(HTMLFormElement* form)
+    {
+        return adoptPtr(new AutocompleteRequest(form));
+    }
+
+    ScriptPromise promise()
+    {
+        return m_resolver->promise();
+    }
+
+    void setResult(HTMLFormElement::AutocompleteResult result)
+    {
+        ASSERT(!m_isResultSet);
+        m_result = result;
+        m_isResultSet = true;
+    }
+
+    void dispatchAndFulfill()
+    {
+        ASSERT(m_isResultSet);
+
+        String reason;
+        if (m_result == HTMLFormElement::AutocompleteResultErrorDisabled)
+            reason = "disabled";
+        else if (m_result == HTMLFormElement::AutocompleteResultErrorCancel)
+            reason = "cancel";
+        else if (m_result == HTMLFormElement::AutocompleteResultErrorInvalid)
+            reason = "invalid";
+
+        RefPtrWillBeRawPtr<Event> event = reason.isEmpty() ? Event::createBubble(EventTypeNames::autocomplete) : AutocompleteErrorEvent::create(reason);
+        event->setTarget(m_form);
+        m_form->dispatchEvent(event.release());
+
+        v8::Isolate* isolate = m_scriptState->isolate();
+        NewScriptState::Scope scope(m_scriptState.get());

[yhirano, 2014/04/17 10:57:48]

Can you use ScriptPromiseResolverWithContext instead of a pair of
ScriptPromiseResolver and NewScriptState?
Currently it doesn't provide a way to resolve a promise with undefined outside a
V8 context, but https://codereview.chromium.org/238723009/ implements the
functionality, which should be landed soon.

[Dan Beam, 2014/04/17 23:02:04]

Done. (patched in your CL locally)

+        if (reason.isEmpty()) {
+            m_resolver->resolve(v8::Undefined(isolate));
+        } else {
+            v8::Handle<v8::Value> error = v8::Exception::Error(v8String(isolate, "requestAutocomplete: failed."));
+            error.As<v8::Object>()->Set(v8String(isolate, "reason"), v8String(isolate, reason));
+            m_resolver->reject(ScriptValue(error, isolate));
+        }
+    }
+
+private:
+    AutocompleteRequest(HTMLFormElement* form)
+        : m_form(form)
+        , m_resolver(ScriptPromiseResolver::create(form->executionContext()))
+        , m_scriptState(NewScriptState::current(toIsolate(form->executionContext())))
+        , m_isResultSet(false)
+    { }
+
+    HTMLFormElement* m_form;
+    RefPtr<ScriptPromiseResolver> m_resolver;
+    RefPtr<NewScriptState> m_scriptState;
+    HTMLFormElement::AutocompleteResult m_result;
+    bool m_isResultSet;
+};
+
 bool HTMLFormElement::rendererIsNeeded(const RenderStyle& style)
 {
     if (!m_wasDemoted)
@@ -416,53 +480,55 @@ void HTMLFormElement::reset()
     m_isInResetFunction = false;
 }
 
-void HTMLFormElement::requestAutocomplete(const Dictionary& details)
+ScriptPromise HTMLFormElement::requestAutocomplete(const Dictionary& details)
 {
-    String errorMessage;
+    OwnPtr<AutocompleteRequest> request = AutocompleteRequest::create(this);
+    ScriptPromise promise = request->promise();
 
+    String errorMessage;
     if (!document().frame())
         errorMessage = "requestAutocomplete: form is not owned by a displayed document.";
     else if (!shouldAutocomplete())
         errorMessage = "requestAutocomplete: form autocomplete attribute is set to off.";
     else if (!UserGestureIndicator::processingUserGesture())
         errorMessage = "requestAutocomplete: must be called in response to a user gesture.";
+    else if (m_pendingAutocompleteRequest)
+        errorMessage = "requestAutocomplete: already in progess.";
 
     if (!errorMessage.isEmpty()) {
         document().addConsoleMessage(RenderingMessageSource, LogMessageLevel, errorMessage);
-        finishRequestAutocomplete(AutocompleteResultErrorDisabled);
+        doFinishRequestAutocomplete(AutocompleteResultErrorDisabled, request.release());
     } else {
+        m_pendingAutocompleteRequest = request.release();
         document().frame()->loader().client()->didRequestAutocomplete(this, details);
     }
+
+    return promise;
 }
 
 void HTMLFormElement::finishRequestAutocomplete(AutocompleteResult result)
 {
-    RefPtrWillBeRawPtr<Event> event = nullptr;
-    if (result == AutocompleteResultSuccess)
-        event = Event::createBubble(EventTypeNames::autocomplete);
-    else if (result == AutocompleteResultErrorDisabled)
-        event = AutocompleteErrorEvent::create("disabled");
-    else if (result == AutocompleteResultErrorCancel)
-        event = AutocompleteErrorEvent::create("cancel");
-    else if (result == AutocompleteResultErrorInvalid)
-        event = AutocompleteErrorEvent::create("invalid");
-    else
-        ASSERT_NOT_REACHED();
+    doFinishRequestAutocomplete(result, m_pendingAutocompleteRequest.release());
+}
 
-    event->setTarget(this);
-    m_pendingAutocompleteEvents.append(event.release());
+void HTMLFormElement::doFinishRequestAutocomplete(AutocompleteResult result, PassOwnPtr<AutocompleteRequest> request)
+{
+    request->setResult(result);
+    m_finishedAutocompleteRequests.append(request);
 
-    // Dispatch events later as this API is meant to work asynchronously in all situations and implementations.
+    // Finish the request later as this API is meant to work asynchronously in all situations and implementations.
     if (!m_requestAutocompleteTimer.isActive())
         m_requestAutocompleteTimer.startOneShot(0, FROM_HERE);
 }
 
 void HTMLFormElement::requestAutocompleteTimerFired(Timer<HTMLFormElement>*)
 {
-    WillBeHeapVector<RefPtrWillBeMember<Event> > pendingEvents;
-    m_pendingAutocompleteEvents.swap(pendingEvents);
-    for (size_t i = 0; i < pendingEvents.size(); ++i)
-        dispatchEvent(pendingEvents[i].release());
+    WillBeHeapVector<OwnPtrWillBeMember<AutocompleteRequest> > finishedRequests;
+    m_finishedAutocompleteRequests.swap(finishedRequests);
+
+    RefPtr<HTMLFormElement> protector(this);
+    for (size_t i = 0; i < finishedRequests.size(); ++i)
+        finishedRequests[i]->dispatchAndFulfill();
 }
 
 void HTMLFormElement::parseAttribute(const QualifiedName& name, const AtomicString& value)