Intersection Observer first draft

Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 58 matching lines @@
 #include "core/dom/DocumentFragment.h"
 #include "core/dom/DocumentLifecycleObserver.h"
 #include "core/dom/DocumentType.h"
 #include "core/dom/Element.h"
 #include "core/dom/ElementDataCache.h"
 #include "core/dom/ElementRegistrationOptions.h"
 #include "core/dom/ElementTraversal.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/ExecutionContextTask.h"
 #include "core/dom/FrameRequestCallback.h"
+#include "core/dom/IntersectionObserver.h"
 #include "core/dom/LayoutTreeBuilderTraversal.h"
 #include "core/dom/MainThreadTaskRunner.h"
 #include "core/dom/Microtask.h"
 #include "core/dom/MutationObserver.h"
 #include "core/dom/NodeChildRemovalTracker.h"
 #include "core/dom/NodeComputedStyle.h"
 #include "core/dom/NodeFilter.h"
 #include "core/dom/NodeIterator.h"
 #include "core/dom/NodeRareData.h"
 #include "core/dom/NodeTraversal.h"
@@ skipping 130 matching lines @@
 #include "wtf/text/StringBuffer.h"
 #include "wtf/text/TextEncodingRegistry.h"
 
 using namespace WTF;
 using namespace Unicode;
 
 namespace blink {
 
 using namespace HTMLNames;
 
+using IntersectionObserverVector = WillBeHeapVector<RefPtrWillBeMember<IntersectionObserver>>;
+
 static const unsigned cMaxWriteRecursionDepth = 21;
 
 // This amount of time must have elapsed before we will even consider scheduling a layout without a delay.
 // FIXME: For faster machines this value can really be lowered to 200.  250 is adequate, but a little high
 // for dual G5s. :)
 static const int cLayoutScheduleThreshold = 250;
 
 // DOM Level 2 says (letters added):
 //
 // a) Name start characters must have one of the categories Ll, Lu, Lo, Lt, Nl.
@@ skipping 176 matching lines @@
     , m_isMobileDocument(false)
     , m_layoutView(0)
 #if !ENABLE(OILPAN)
     , m_weakFactory(this)
 #endif
     , m_contextDocument(initializer.contextDocument())
     , m_hasFullscreenSupplement(false)
     , m_loadEventDelayCount(0)
     , m_loadEventDelayTimer(this, &Document::loadEventDelayTimerFired)
     , m_pluginLoadingTimer(this, &Document::pluginLoadingTimerFired)
+    , m_deliverIntersectionObservationsTimer(this, &Document::deliverIntersectionObservationsTimerFired)
     , m_documentTiming(*this)
     , m_writeRecursionIsTooDeep(false)
     , m_writeRecursionDepth(0)
     , m_taskRunner(MainThreadTaskRunner::create(this))
     , m_registrationContext(initializer.registrationContext(this))
     , m_elementDataCacheClearTimer(this, &Document::elementDataCacheClearTimerFired)
     , m_timeline(AnimationTimeline::create(this))
     , m_templateDocumentHost(nullptr)
     , m_didAssociateFormControlsTimer(this, &Document::didAssociateFormControlsTimerFired)
     , m_hasViewportUnits(false)
@@ skipping 5190 matching lines @@
                     if (!context->securityOrigin()->isPotentiallyTrustworthy(errorMessage))
                         return false;
                 }
             }
             context = context->parentDocument();
         }
     }
     return true;
 }
 
+void Document::activateIntersectionObserver(IntersectionObserver& observer)
+{
+    if (m_activeIntersectionObservers.isEmpty())
+        m_deliverIntersectionObservationsTimer.startOneShot(0, FROM_HERE);
+
+    m_activeIntersectionObservers.add(&observer);
+}
+
+void Document::resumeSuspendedIntersectionObservers()
+{
+    ASSERT(isMainThread());
+    if (m_suspendedIntersectionObservers.isEmpty())
+        return;
+
+    IntersectionObserverVector suspended;
+    copyToVector(m_suspendedIntersectionObservers, suspended);
+    for (size_t i = 0; i < suspended.size(); ++i) {
+        if (!suspended[i]->shouldBeSuspended()) {
+            m_suspendedIntersectionObservers.remove(suspended[i]);
+            activateIntersectionObserver(*suspended[i]);
+        }
+    }
+}
+
+void Document::deliverIntersectionObservationsTimerFired(Timer<Document>*)
+{
+    ASSERT(isMainThread());
+    IntersectionObserverVector observers;
+    copyToVector(m_activeIntersectionObservers, observers);
+    m_activeIntersectionObservers.clear();
+    for (size_t i = 0; i < observers.size(); ++i) {
+        if (observers[i]->shouldBeSuspended())
+            m_suspendedIntersectionObservers.add(observers[i]);
+        else
+            observers[i]->deliver();
+    }
+}
+
 DEFINE_TRACE(Document)
 {
 #if ENABLE(OILPAN)
     visitor->trace(m_importsController);
     visitor->trace(m_docType);
     visitor->trace(m_implementation);
     visitor->trace(m_autofocusElement);
     visitor->trace(m_focusedElement);
     visitor->trace(m_hoverNode);
     visitor->trace(m_activeHoverElement);
@@ skipping 36 matching lines @@
     visitor->trace(m_timers);
     visitor->trace(m_templateDocument);
     visitor->trace(m_templateDocumentHost);
     visitor->trace(m_visibilityObservers);
     visitor->trace(m_userActionElements);
     visitor->trace(m_svgExtensions);
     visitor->trace(m_timeline);
     visitor->trace(m_compositorPendingAnimations);
     visitor->trace(m_contextDocument);
     visitor->trace(m_canvasFontCache);
+    visitor->trace(m_activeIntersectionObservers);
+    visitor->trace(m_suspendedIntersectionObservers);
     WillBeHeapSupplementable<Document>::trace(visitor);
 #endif
     TreeScope::trace(visitor);
     ContainerNode::trace(visitor);
     ExecutionContext::trace(visitor);
     DocumentLifecycleNotifier::trace(visitor);
     SecurityContext::trace(visitor);
 }
 
 template class CORE_TEMPLATE_EXPORT WillBeHeapSupplement<Document>;
 
 } // namespace blink
 
 #ifndef NDEBUG
 using namespace blink;
 void showLiveDocumentInstances()
 {
     Document::WeakDocumentSet& set = Document::liveDocumentSet();
     fprintf(stderr, "There are %u documents currently alive:\n", set.size());
     for (Document* document : set)
         fprintf(stderr, "- Document %p URL: %s\n", document, document->url().string().utf8().data());
 }
 #endif