Blink-side contiguous allocation of display items.

Source/platform/graphics/paint/DisplayItemList.cpp

 // Copyright 2014 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 "config.h"
 #include "platform/graphics/paint/DisplayItemList.h"
 
 #include "platform/NotImplemented.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/TraceEvent.h"
@@ skipping 14 matching lines @@
 
 namespace blink {
 
 const DisplayItems& DisplayItemList::displayItems() const
 {
     ASSERT(RuntimeEnabledFeatures::slimmingPaintEnabled());
     ASSERT(m_newDisplayItems.isEmpty());
     return m_currentDisplayItems;
 }
 
-void DisplayItemList::add(WTF::PassOwnPtr<DisplayItem> displayItem)
+void DisplayItemList::processNewItem(DisplayItem& addedDisplayItem)
 {
     ASSERT(RuntimeEnabledFeatures::slimmingPaintEnabled());
     ASSERT(!m_constructionDisabled);
-    ASSERT(!skippingCache() || !displayItem->isCached());
+    ASSERT(!skippingCache() || !addedDisplayItem.isCached());
 
-    if (displayItem->isEnd()) {
-        ASSERT(!m_newDisplayItems.isEmpty());
-        if (m_newDisplayItems.last().isBegin() && !m_newDisplayItems.last().drawsContent()) {
-            ASSERT(displayItem->isEndAndPairedWith(m_newDisplayItems.last().type()));
-            // Remove the beginning display item of this empty pair.
-            m_newDisplayItems.removeLast();
+    if (addedDisplayItem.isEnd()) {
+        ASSERT(m_newDisplayItems.size() >= 2);
+        DisplayItems::ItemHandle previousDisplayItem = m_newDisplayItems[m_newDisplayItems.size() - 2];
+        if (previousDisplayItem.isBegin() && !previousDisplayItem.drawsContent()) {
 #if ENABLE(ASSERT)
-            // Also remove the index pointing to the removed display item.
-            DisplayItemIndicesByClientMap::iterator it = m_newDisplayItemIndicesByClient.find(displayItem->client());
+            ASSERT(addedDisplayItem.isEndAndPairedWith(previousDisplayItem.type()));
+            // Remove the index pointing to the begin display item.
+            DisplayItemIndicesByClientMap::iterator it = m_newDisplayItemIndicesByClient.find(previousDisplayItem.client());
             if (it != m_newDisplayItemIndicesByClient.end()) {
                 Vector<size_t>& indices = it->value;
-                if (!indices.isEmpty() && indices.last() == m_newDisplayItems.size())
+                if (!indices.isEmpty() && indices.last() == m_newDisplayItems.size() - 1)
                     indices.removeLast();
             }
 #endif
+            // Remove the no-op pair.
+            m_newDisplayItems.removeLast();
+            m_newDisplayItems.removeLast();
             return;
         }
     }
 
     if (!m_scopeStack.isEmpty())
-        displayItem->setScope(m_scopeStack.last().id, m_scopeStack.last().client);
+        addedDisplayItem.setScope(m_scopeStack.last().id, m_scopeStack.last().client);
 
 #if ENABLE(ASSERT)
-    size_t index = findMatchingItemFromIndex(displayItem->id(), displayItem->type(), m_newDisplayItemIndicesByClient, m_newDisplayItems);
-    if (index != kNotFound) {
-#ifndef NDEBUG
-        showDebugData();
-        WTFLogAlways("DisplayItem %s has duplicated id with previous %s (index=%d)\n",
-            displayItem->asDebugString().utf8().data(), m_newDisplayItems[index].asDebugString().utf8().data(), static_cast<int>(index));
+    addItemToIndex(addedDisplayItem.client(), addedDisplayItem.type(), m_newDisplayItems.size() - 1, m_newDisplayItemIndicesByClient);
 #endif
-        ASSERT_NOT_REACHED();

[Xianzhu, 2015/06/19 16:19:11]

Is the above code moved elsewhere or removed?

-    }
-    addItemToIndex(displayItem->client(), displayItem->type(), m_newDisplayItems.size(), m_newDisplayItemIndicesByClient);
-#endif // ENABLE(ASSERT)
 
-    ASSERT(!displayItem->skippedCache()); // Only DisplayItemList can set the flag.
+    ASSERT(!addedDisplayItem.skippedCache()); // Only DisplayItemList can set the flag.
     if (skippingCache())
-        displayItem->setSkippedCache();
-
-    m_newDisplayItems.append(displayItem);
+        addedDisplayItem.setSkippedCache();
 }
 
 void DisplayItemList::beginScope(DisplayItemClient client)
 {
     ClientScopeIdMap::iterator it = m_clientScopeIdMap.find(client);
     int scopeId;
     if (it == m_clientScopeIdMap.end()) {
         m_clientScopeIdMap.add(client, 0);
         scopeId = 0;
     } else {
@@ skipping 379 matching lines @@
 
 void DisplayItemList::replay(GraphicsContext& context) const
 {
     TRACE_EVENT0("blink,benchmark", "DisplayItemList::replay");
     ASSERT(m_newDisplayItems.isEmpty());
     for (auto& displayItem : m_currentDisplayItems)
         displayItem.replay(context);
 }
 
 } // namespace blink