*** DO NOT LAND *** Attempt to understand Regions complexity

Source/core/dom/NamedFlowCollection.cpp

-/*
- * Copyright (C) 2012 Adobe Systems Incorporated. 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 notice, this list of conditions and the following
- *    disclaimer in the documentation and/or other materials
- *    provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER "AS IS" AND ANY
- * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE
- * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
- * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
- * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
- * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
- * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#include "config.h"
-#include "core/dom/NamedFlowCollection.h"
-
-#include "RuntimeEnabledFeatures.h"
-#include "core/dom/DOMNamedFlowCollection.h"
-#include "core/dom/Document.h"
-#include "core/inspector/InspectorInstrumentation.h"
-#include "wtf/text/AtomicString.h"
-#include "wtf/text/StringHash.h"
-#include "wtf/text/WTFString.h"
-
-namespace WebCore {
-
-NamedFlowCollection::NamedFlowCollection(Document* document)
-    : DocumentLifecycleObserver(document)
-{
-    ASSERT(RuntimeEnabledFeatures::cssRegionsEnabled());
-}
-
-Vector<RefPtr<NamedFlow> > NamedFlowCollection::namedFlows()
-{
-    Vector<RefPtr<NamedFlow> > namedFlows;
-
-    for (NamedFlowSet::iterator it = m_namedFlows.begin(); it != m_namedFlows.end(); ++it) {
-        if ((*it)->flowState() == NamedFlow::FlowStateNull)
-            continue;
-
-        namedFlows.append(RefPtr<NamedFlow>(*it));
-    }
-
-    return namedFlows;
-}
-
-// Takes an AtomicString in argument because RenderStyle::flowThread() returns an AtomicString.
-NamedFlow* NamedFlowCollection::flowByName(const AtomicString& flowName)
-{
-    NamedFlowSet::iterator it = m_namedFlows.find<NamedFlowHashTranslator>(flowName);
-    if (it == m_namedFlows.end() || (*it)->flowState() == NamedFlow::FlowStateNull)
-        return 0;
-
-    return *it;
-}
-
-// Takes an AtomicString in argument because RenderStyle::flowThread() returns an AtomicString.
-PassRefPtr<NamedFlow> NamedFlowCollection::ensureFlowWithName(const AtomicString& flowName)
-{
-    NamedFlowSet::iterator it = m_namedFlows.find<NamedFlowHashTranslator>(flowName);
-    if (it != m_namedFlows.end()) {
-        NamedFlow* namedFlow = *it;
-        ASSERT(namedFlow->flowState() == NamedFlow::FlowStateNull);
-
-        return namedFlow;
-    }
-
-    RefPtr<NamedFlow> newFlow = NamedFlow::create(this, flowName);
-    m_namedFlows.add(newFlow.get());
-
-    InspectorInstrumentation::didCreateNamedFlow(document(), newFlow.get());
-
-    return newFlow.release();
-}
-
-void NamedFlowCollection::discardNamedFlow(NamedFlow* namedFlow)
-{
-    // The document is not valid anymore so the collection will be destroyed anyway.
-    if (!document())
-        return;
-
-    ASSERT(namedFlow->flowState() == NamedFlow::FlowStateNull);
-    ASSERT(m_namedFlows.contains(namedFlow));
-
-    InspectorInstrumentation::willRemoveNamedFlow(document(), namedFlow);
-
-    m_namedFlows.remove(namedFlow);
-}
-
-Document* NamedFlowCollection::document() const
-{
-    return lifecycleContext();
-}
-
-PassRefPtr<DOMNamedFlowCollection> NamedFlowCollection::createCSSOMSnapshot()
-{
-    Vector<NamedFlow*> createdFlows;
-    for (NamedFlowSet::iterator it = m_namedFlows.begin(); it != m_namedFlows.end(); ++it)
-        if ((*it)->flowState() == NamedFlow::FlowStateCreated)
-            createdFlows.append(*it);
-    return DOMNamedFlowCollection::create(createdFlows);
-}
-
-// The HashFunctions object used by the HashSet to compare between NamedFlows.
-// It is safe to set safeToCompareToEmptyOrDeleted because the HashSet will never contain null pointers or deleted values.
-struct NamedFlowCollection::NamedFlowHashFunctions {
-    static unsigned hash(NamedFlow* key) { return DefaultHash<AtomicString>::Hash::hash(key->name()); }
-    static bool equal(NamedFlow* a, NamedFlow* b) { return a->name() == b->name(); }
-    static const bool safeToCompareToEmptyOrDeleted = true;
-};
-
-// The HashTranslator is used to lookup a NamedFlow in the set using a name.
-struct NamedFlowCollection::NamedFlowHashTranslator {
-    static unsigned hash(const AtomicString& key) { return DefaultHash<AtomicString>::Hash::hash(key); }
-    static bool equal(NamedFlow* a, const AtomicString& b) { return a->name() == b; }
-};
-
-} // namespace WebCore