Moving GraphicsContext and dependencies from core to platform.

Source/core/platform/graphics/Canvas2DLayerManager.cpp

-/*
-Copyright (C) 2012 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
-    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 APPLE INC. AND ITS 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 APPLE INC. OR ITS 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/platform/graphics/Canvas2DLayerManager.h"
-
-#include "public/platform/Platform.h"
-#include "wtf/StdLibExtras.h"
-
-using blink::WebThread;
-
-namespace {
-enum {
-    DefaultMaxBytesAllocated = 64*1024*1024,
-    DefaultTargetBytesAllocated = 16*1024*1024,
-};
-}
-
-namespace WebCore {
-
-Canvas2DLayerManager::Canvas2DLayerManager()
-    : m_bytesAllocated(0)
-    , m_maxBytesAllocated(DefaultMaxBytesAllocated)
-    , m_targetBytesAllocated(DefaultTargetBytesAllocated)
-    , m_taskObserverActive(false)
-{
-}
-
-Canvas2DLayerManager::~Canvas2DLayerManager()
-{
-    ASSERT(!m_bytesAllocated);
-    ASSERT(!m_layerList.head());
-    ASSERT(!m_taskObserverActive);
-}
-
-void Canvas2DLayerManager::init(size_t maxBytesAllocated, size_t targetBytesAllocated)
-{
-    ASSERT(maxBytesAllocated >= targetBytesAllocated);
-    m_maxBytesAllocated = maxBytesAllocated;
-    m_targetBytesAllocated = targetBytesAllocated;
-    if (m_taskObserverActive) {
-        blink::Platform::current()->currentThread()->removeTaskObserver(this);
-        m_taskObserverActive = false;
-    }
-}
-
-Canvas2DLayerManager& Canvas2DLayerManager::get()
-{
-    DEFINE_STATIC_LOCAL(Canvas2DLayerManager, manager, ());
-    return manager;
-}
-
-void Canvas2DLayerManager::willProcessTask()
-{
-}
-
-void Canvas2DLayerManager::didProcessTask()
-{
-    // Called after the script action for the current frame has been processed.
-    ASSERT(m_taskObserverActive);
-    blink::Platform::current()->currentThread()->removeTaskObserver(this);
-    m_taskObserverActive = false;
-    for (Canvas2DLayerBridge* layer = m_layerList.head(); layer; layer = layer->next())
-        layer->limitPendingFrames();
-}
-
-void Canvas2DLayerManager::layerDidDraw(Canvas2DLayerBridge* layer)
-{
-    if (isInList(layer)) {
-        if (layer != m_layerList.head()) {
-            m_layerList.remove(layer);
-            m_layerList.push(layer); // Set as MRU
-        }
-    } else
-        addLayerToList(layer);
-
-    if (!m_taskObserverActive) {
-        m_taskObserverActive = true;
-        // Schedule a call to didProcessTask() after completion of the current script task.
-        blink::Platform::current()->currentThread()->addTaskObserver(this);
-    }
-}
-
-void Canvas2DLayerManager::addLayerToList(Canvas2DLayerBridge* layer)
-{
-    ASSERT(!isInList(layer));
-    m_bytesAllocated += layer->bytesAllocated();
-    m_layerList.push(layer); // Set as MRU
-}
-
-void Canvas2DLayerManager::layerAllocatedStorageChanged(Canvas2DLayerBridge* layer, intptr_t deltaBytes)
-{
-    if (!isInList(layer))
-        addLayerToList(layer);
-    else {
-        ASSERT((intptr_t)m_bytesAllocated + deltaBytes >= 0);
-        m_bytesAllocated = (intptr_t)m_bytesAllocated + deltaBytes;
-    }
-    if (deltaBytes > 0)
-        freeMemoryIfNecessary();
-}
-
-void Canvas2DLayerManager::layerToBeDestroyed(Canvas2DLayerBridge* layer)
-{
-    if (isInList(layer))
-        removeLayerFromList(layer);
-}
-
-void Canvas2DLayerManager::freeMemoryIfNecessary()
-{
-    if (m_bytesAllocated > m_maxBytesAllocated) {
-        // Pass 1: Free memory from caches
-        Canvas2DLayerBridge* layer = m_layerList.tail(); // LRU
-        while (m_bytesAllocated > m_targetBytesAllocated && layer) {
-            layer->freeMemoryIfPossible(m_bytesAllocated - m_targetBytesAllocated);
-            layer = layer->prev();
-        }
-
-        // Pass 2: Flush canvases
-        Canvas2DLayerBridge* leastRecentlyUsedLayer = m_layerList.tail();
-        while (m_bytesAllocated > m_targetBytesAllocated && leastRecentlyUsedLayer) {
-            leastRecentlyUsedLayer->flush();
-            leastRecentlyUsedLayer->freeMemoryIfPossible(~0);
-            removeLayerFromList(leastRecentlyUsedLayer);
-            leastRecentlyUsedLayer = m_layerList.tail();
-        }
-    }
-}
-
-void Canvas2DLayerManager::removeLayerFromList(Canvas2DLayerBridge* layer)
-{
-    ASSERT(isInList(layer));
-    m_bytesAllocated -= layer->bytesAllocated();
-    m_layerList.remove(layer);
-    layer->setNext(0);
-    layer->setPrev(0);
-}
-
-bool Canvas2DLayerManager::isInList(Canvas2DLayerBridge* layer)
-{
-    return layer->prev() || m_layerList.head() == layer;
-}
-
-}
-