third_party/WebKit/Source/core/observer/ResizeObserverController.cpp

// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "core/observer/ResizeObserverController.h"

#include "core/observer/ResizeObserver.h"


namespace blink {

ResizeObserverController::ResizeObserverController()
    : m_observersChanged(false)
{
}

void ResizeObserverController::addObserver(ResizeObserver& observer)
{
    m_observers.add(&observer);
}

size_t ResizeObserverController::gatherObservations(size_t deeperThan)
{
    size_t shallowest = ResizeObserverController::kDepthBottom;
    if (!m_observersChanged)
        return shallowest;
    for (auto& observer : m_observers) {
        size_t depth = observer->gatherObservations(deeperThan);
        if (depth < shallowest)
            shallowest = depth;
    }
    return shallowest;
}

bool ResizeObserverController::skippedObservations()
{
    for (auto& observer : m_observers) {
        if (observer->skippedObservations())
            return true;
    }
    return false;
}

void ResizeObserverController::deliverObservations()
{
    m_observersChanged = false;
    // Copy is needed because m_observers might get modified during deliverObservations.
    HeapVector<Member<ResizeObserver>> observers;
    copyToVector(m_observers, observers);

    for (auto& observer : observers) {
        if (observer) {
            observer->deliverObservations();
            m_observersChanged = m_observersChanged || observer->hasElementSizeChanged();
        }
    }
}

void ResizeObserverController::clearObservations()
{
    for (auto& observer : m_observers)
        observer->clearObservations();
}

DEFINE_TRACE(ResizeObserverController)
{
    visitor->trace(m_observers);
}

} // namespace blink