Avoid duplicate hash lookups in CustomElementScheduler::ensureCallbackQueue

Source/core/dom/custom/CustomElementScheduler.cpp

 /*
  * 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:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 30 matching lines @@
 #include "core/dom/custom/CustomElementMicrotaskResolutionStep.h"
 #include "core/dom/custom/CustomElementRegistrationContext.h"
 #include "core/html/imports/HTMLImportChild.h"
 
 namespace WebCore {
 
 class HTMLImport;
 
 void CustomElementScheduler::scheduleCreatedCallback(PassRefPtr<CustomElementLifecycleCallbacks> callbacks, PassRefPtr<Element> element)
 {
-    CustomElementCallbackQueue* queue = instance().schedule(element);
-    queue->append(CustomElementCallbackInvocation::createInvocation(callbacks, CustomElementLifecycleCallbacks::Created));
+    CustomElementCallbackQueue& queue = instance().schedule(element);
+    queue.append(CustomElementCallbackInvocation::createInvocation(callbacks, CustomElementLifecycleCallbacks::Created));
 }
 
 void CustomElementScheduler::scheduleAttributeChangedCallback(PassRefPtr<CustomElementLifecycleCallbacks> callbacks, PassRefPtr<Element> element, const AtomicString& name, const AtomicString& oldValue, const AtomicString& newValue)
 {
     if (!callbacks->hasAttributeChangedCallback())
         return;
 
-    CustomElementCallbackQueue* queue = instance().schedule(element);
-    queue->append(CustomElementCallbackInvocation::createAttributeChangedInvocation(callbacks, name, oldValue, newValue));
+    CustomElementCallbackQueue& queue = instance().schedule(element);
+    queue.append(CustomElementCallbackInvocation::createAttributeChangedInvocation(callbacks, name, oldValue, newValue));
 }
 
 void CustomElementScheduler::scheduleAttachedCallback(PassRefPtr<CustomElementLifecycleCallbacks> callbacks, PassRefPtr<Element> element)
 {
     if (!callbacks->hasAttachedCallback())
         return;
 
-    CustomElementCallbackQueue* queue = instance().schedule(element);
-    queue->append(CustomElementCallbackInvocation::createInvocation(callbacks, CustomElementLifecycleCallbacks::Attached));
+    CustomElementCallbackQueue& queue = instance().schedule(element);
+    queue.append(CustomElementCallbackInvocation::createInvocation(callbacks, CustomElementLifecycleCallbacks::Attached));
 }
 
 void CustomElementScheduler::scheduleDetachedCallback(PassRefPtr<CustomElementLifecycleCallbacks> callbacks, PassRefPtr<Element> element)
 {
     if (!callbacks->hasDetachedCallback())
         return;
 
-    CustomElementCallbackQueue* queue = instance().schedule(element);
-    queue->append(CustomElementCallbackInvocation::createInvocation(callbacks, CustomElementLifecycleCallbacks::Detached));
+    CustomElementCallbackQueue& queue = instance().schedule(element);
+    queue.append(CustomElementCallbackInvocation::createInvocation(callbacks, CustomElementLifecycleCallbacks::Detached));
 }
 
 void CustomElementScheduler::resolveOrScheduleResolution(PassRefPtr<CustomElementRegistrationContext> context, PassRefPtr<Element> element, const CustomElementDescriptor& descriptor)
 {
     if (CustomElementCallbackDispatcher::inCallbackDeliveryScope()) {
         context->resolve(element.get(), descriptor);
         return;
     }
 
     HTMLImport* import = element->document().import();
@@ skipping 15 matching lines @@
 
     return rawStep;
 }
 
 CustomElementScheduler& CustomElementScheduler::instance()
 {
     DEFINE_STATIC_LOCAL(CustomElementScheduler, instance, ());
     return instance;
 }
 
-CustomElementCallbackQueue* CustomElementScheduler::ensureCallbackQueue(PassRefPtr<Element> element)
+CustomElementCallbackQueue& CustomElementScheduler::ensureCallbackQueue(PassRefPtr<Element> element)
 {
-    Element* key = element.get();
-    ElementCallbackQueueMap::iterator it = m_elementCallbackQueueMap.find(key);
-    if (it == m_elementCallbackQueueMap.end())
-        return m_elementCallbackQueueMap.add(key, CustomElementCallbackQueue::create(element)).storedValue->value.get();
-    return it->value.get();
+    ElementCallbackQueueMap::ValueType* it = m_elementCallbackQueueMap.add(element.get(), nullptr).storedValue;
+    if (!it->value)
+        it->value = CustomElementCallbackQueue::create(element);
+    return *it->value.get();
 }
 
 void CustomElementScheduler::callbackDispatcherDidFinish()
 {
     if (CustomElementMicrotaskDispatcher::instance().elementQueueIsEmpty())
         instance().clearElementCallbackQueueMap();
 }
 
 void CustomElementScheduler::microtaskDispatcherDidFinish()
 {
     ASSERT(!CustomElementCallbackDispatcher::inCallbackDeliveryScope());
     instance().clearElementCallbackQueueMap();
 }
 
 void CustomElementScheduler::clearElementCallbackQueueMap()
 {
     ElementCallbackQueueMap emptyMap;
     m_elementCallbackQueueMap.swap(emptyMap);
 }
 
 // Finds or creates the callback queue for element.
-CustomElementCallbackQueue* CustomElementScheduler::schedule(PassRefPtr<Element> passElement)
+CustomElementCallbackQueue& CustomElementScheduler::schedule(PassRefPtr<Element> passElement)
 {
     RefPtr<Element> element(passElement);
 
-    CustomElementCallbackQueue* callbackQueue = ensureCallbackQueue(element);
-    if (callbackQueue->inCreatedCallback()) {
+    CustomElementCallbackQueue& callbackQueue = ensureCallbackQueue(element);
+    if (callbackQueue.inCreatedCallback()) {
         // Don't move it. Authors use the createdCallback like a
         // constructor. By not moving it, the createdCallback
         // completes before any other callbacks are entered for this
         // element.
         return callbackQueue;
     }
 
     if (CustomElementCallbackDispatcher::inCallbackDeliveryScope()) {
         // The processing stack is active.
-        CustomElementCallbackDispatcher::instance().enqueue(callbackQueue);
+        CustomElementCallbackDispatcher::instance().enqueue(&callbackQueue);
         return callbackQueue;
     }
 
-    CustomElementMicrotaskDispatcher::instance().enqueue(callbackQueue);
+    CustomElementMicrotaskDispatcher::instance().enqueue(&callbackQueue);
     return callbackQueue;
 }
 
 } // namespace WebCore