root/Source/core/dom/MutationObserver.cpp

/* [<][>][^][v][top][bottom][index][help] */

DEFINITIONS

This source file includes following definitions.
  1. create
  2. m_priority
  3. observe
  4. takeRecords
  5. disconnect
  6. observationStarted
  7. observationEnded
  8. activeMutationObservers
  9. suspendedMutationObservers
  10. activateObserver
  11. enqueueMutationRecord
  12. setHasTransientRegistration
  13. getObservedNodes
  14. canDeliver
  15. deliver
  16. resumeSuspendedObservers
  17. deliverMutations

/*
 * Copyright (C) 2011 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:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "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
 * OWNER OR CONTRIBUTORS 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/MutationObserver.h"

#include <algorithm>
#include "bindings/v8/Dictionary.h"
#include "bindings/v8/ExceptionState.h"
#include "core/dom/Document.h"
#include "core/dom/ExceptionCode.h"
#include "core/dom/Microtask.h"
#include "core/dom/MutationCallback.h"
#include "core/dom/MutationObserverRegistration.h"
#include "core/dom/MutationRecord.h"
#include "core/dom/Node.h"
#include "core/inspector/InspectorInstrumentation.h"
#include "wtf/MainThread.h"

namespace WebCore {

static unsigned s_observerPriority = 0;

struct MutationObserver::ObserverLessThan {
    bool operator()(const RefPtr<MutationObserver>& lhs, const RefPtr<MutationObserver>& rhs)
    {
        return lhs->m_priority < rhs->m_priority;
    }
};

PassRefPtr<MutationObserver> MutationObserver::create(PassOwnPtr<MutationCallback> callback)
{
    ASSERT(isMainThread());
    return adoptRef(new MutationObserver(callback));
}

MutationObserver::MutationObserver(PassOwnPtr<MutationCallback> callback)
    : m_callback(callback)
    , m_priority(s_observerPriority++)
{
    ScriptWrappable::init(this);
}

MutationObserver::~MutationObserver()
{
    ASSERT(m_registrations.isEmpty());
    if (!m_records.isEmpty())
        InspectorInstrumentation::didClearAllMutationRecords(m_callback->executionContext(), this);
}

void MutationObserver::observe(Node* node, const Dictionary& optionsDictionary, ExceptionState& exceptionState)
{
    if (!node) {
        exceptionState.throwDOMException(NotFoundError, "The provided node was null.");
        return;
    }

    MutationObserverOptions options = 0;

    bool attributeOldValue = false;
    bool attributeOldValuePresent = optionsDictionary.get("attributeOldValue", attributeOldValue);
    if (attributeOldValue)
        options |= AttributeOldValue;

    HashSet<AtomicString> attributeFilter;
    bool attributeFilterPresent = optionsDictionary.get("attributeFilter", attributeFilter);
    if (attributeFilterPresent)
        options |= AttributeFilter;

    bool attributes = false;
    bool attributesPresent = optionsDictionary.get("attributes", attributes);
    if (attributes || (!attributesPresent && (attributeOldValuePresent || attributeFilterPresent)))
        options |= Attributes;

    bool characterDataOldValue = false;
    bool characterDataOldValuePresent = optionsDictionary.get("characterDataOldValue", characterDataOldValue);
    if (characterDataOldValue)
        options |= CharacterDataOldValue;

    bool characterData = false;
    bool characterDataPresent = optionsDictionary.get("characterData", characterData);
    if (characterData || (!characterDataPresent && characterDataOldValuePresent))
        options |= CharacterData;

    bool childListValue = false;
    if (optionsDictionary.get("childList", childListValue) && childListValue)
        options |= ChildList;

    bool subtreeValue = false;
    if (optionsDictionary.get("subtree", subtreeValue) && subtreeValue)
        options |= Subtree;

    if (!(options & Attributes)) {
        if (options & AttributeOldValue) {
            exceptionState.throwTypeError("The options object may only set 'attributeOldValue' to true when 'attributes' is true or not present.");
            return;
        }
        if (options & AttributeFilter) {
            exceptionState.throwTypeError("The options object may only set 'attributeFilter' when 'attributes' is true or not present.");
            return;
        }
    }
    if (!((options & CharacterData) || !(options & CharacterDataOldValue))) {
        exceptionState.throwTypeError("The options object may only set 'characterDataOldValue' to true when 'characterData' is true or not present.");
        return;
    }

    if (!(options & (Attributes | CharacterData | ChildList))) {
        exceptionState.throwTypeError("The options object must set at least one of 'attributes', 'characterData', or 'childList' to true.");
        return;
    }

    node->registerMutationObserver(*this, options, attributeFilter);
}

Vector<RefPtr<MutationRecord> > MutationObserver::takeRecords()
{
    Vector<RefPtr<MutationRecord> > records;
    records.swap(m_records);
    InspectorInstrumentation::didClearAllMutationRecords(m_callback->executionContext(), this);
    return records;
}

void MutationObserver::disconnect()
{
    m_records.clear();
    InspectorInstrumentation::didClearAllMutationRecords(m_callback->executionContext(), this);
    HashSet<MutationObserverRegistration*> registrations(m_registrations);
    for (HashSet<MutationObserverRegistration*>::iterator iter = registrations.begin(); iter != registrations.end(); ++iter)
        (*iter)->unregister();
}

void MutationObserver::observationStarted(MutationObserverRegistration* registration)
{
    ASSERT(!m_registrations.contains(registration));
    m_registrations.add(registration);
}

void MutationObserver::observationEnded(MutationObserverRegistration* registration)
{
    ASSERT(m_registrations.contains(registration));
    m_registrations.remove(registration);
}

typedef HashSet<RefPtr<MutationObserver> > MutationObserverSet;

static MutationObserverSet& activeMutationObservers()
{
    DEFINE_STATIC_LOCAL(MutationObserverSet, activeObservers, ());
    return activeObservers;
}

static MutationObserverSet& suspendedMutationObservers()
{
    DEFINE_STATIC_LOCAL(MutationObserverSet, suspendedObservers, ());
    return suspendedObservers;
}

static void activateObserver(PassRefPtr<MutationObserver> observer)
{
    if (activeMutationObservers().isEmpty())
        Microtask::enqueueMicrotask(&MutationObserver::deliverMutations);

    activeMutationObservers().add(observer);
}

void MutationObserver::enqueueMutationRecord(PassRefPtr<MutationRecord> mutation)
{
    ASSERT(isMainThread());
    m_records.append(mutation);
    activateObserver(this);
    InspectorInstrumentation::didEnqueueMutationRecord(m_callback->executionContext(), this);
}

void MutationObserver::setHasTransientRegistration()
{
    ASSERT(isMainThread());
    activateObserver(this);
}

HashSet<Node*> MutationObserver::getObservedNodes() const
{
    HashSet<Node*> observedNodes;
    for (HashSet<MutationObserverRegistration*>::const_iterator iter = m_registrations.begin(); iter != m_registrations.end(); ++iter)
        (*iter)->addRegistrationNodesToSet(observedNodes);
    return observedNodes;
}

bool MutationObserver::canDeliver()
{
    return !m_callback->executionContext()->activeDOMObjectsAreSuspended();
}

void MutationObserver::deliver()
{
    ASSERT(canDeliver());

    // Calling clearTransientRegistrations() can modify m_registrations, so it's necessary
    // to make a copy of the transient registrations before operating on them.
    Vector<MutationObserverRegistration*, 1> transientRegistrations;
    for (HashSet<MutationObserverRegistration*>::iterator iter = m_registrations.begin(); iter != m_registrations.end(); ++iter) {
        if ((*iter)->hasTransientRegistrations())
            transientRegistrations.append(*iter);
    }
    for (size_t i = 0; i < transientRegistrations.size(); ++i)
        transientRegistrations[i]->clearTransientRegistrations();

    if (m_records.isEmpty())
        return;

    Vector<RefPtr<MutationRecord> > records;
    records.swap(m_records);

    InspectorInstrumentation::willDeliverMutationRecords(m_callback->executionContext(), this);
    m_callback->call(records, this);
    InspectorInstrumentation::didDeliverMutationRecords(m_callback->executionContext());
}

void MutationObserver::resumeSuspendedObservers()
{
    ASSERT(isMainThread());
    if (suspendedMutationObservers().isEmpty())
        return;

    Vector<RefPtr<MutationObserver> > suspended;
    copyToVector(suspendedMutationObservers(), suspended);
    for (size_t i = 0; i < suspended.size(); ++i) {
        if (suspended[i]->canDeliver()) {
            suspendedMutationObservers().remove(suspended[i]);
            activateObserver(suspended[i]);
        }
    }
}

void MutationObserver::deliverMutations()
{
    ASSERT(isMainThread());
    Vector<RefPtr<MutationObserver> > observers;
    copyToVector(activeMutationObservers(), observers);
    activeMutationObservers().clear();
    std::sort(observers.begin(), observers.end(), ObserverLessThan());
    for (size_t i = 0; i < observers.size(); ++i) {
        if (observers[i]->canDeliver())
            observers[i]->deliver();
        else
            suspendedMutationObservers().add(observers[i]);
    }
}

} // namespace WebCore

/* [<][>][^][v][top][bottom][index][help] */