Remove begin/end subseq. display items, and store on PaintController instead.

third_party/WebKit/Source/platform/graphics/paint/PaintController.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 "platform/graphics/paint/PaintController.h"
 
 #include "platform/graphics/GraphicsLayer.h"
 #include "platform/graphics/paint/DrawingDisplayItem.h"
 #include "platform/instrumentation/tracing/TraceEvent.h"
 #include "platform/wtf/AutoReset.h"
@@ skipping 81 matching lines @@
 
   if (RuntimeEnabledFeatures::paintUnderInvalidationCheckingEnabled() &&
       isCheckingUnderInvalidation()) {
     // We are checking under-invalidation of an ancestor subsequence enclosing
     // this one. The ancestor subsequence is supposed to have already "copied",
     // so we should let the client continue to actually paint the descendant
     // subsequences without "copying".
     return false;
   }
 
-  size_t cachedItem =
-      findCachedItem(DisplayItem::Id(client, DisplayItem::kSubsequence));
-  if (cachedItem == kNotFound) {
-    NOTREACHED();
+  SubsequenceMarkers* markers = getSubsequenceMarkers(client);
+  if (!markers) {
     return false;
   }
 
   // |cachedItem| will point to the first item after the subsequence or end of
   // the current list.
   ensureNewDisplayItemListInitialCapacity();
-  copyCachedSubsequence(cachedItem);
 
-  m_nextItemToMatch = cachedItem;
-  // Items before |cachedItem| have been copied so we don't need to index them.
-  if (cachedItem > m_nextItemToIndex)
-    m_nextItemToIndex = cachedItem;
+  size_t sizeBeforeCopy = m_newDisplayItemList.size();
+  copyCachedSubsequence(markers->start, markers->end);
+
+  if (!RuntimeEnabledFeatures::paintUnderInvalidationCheckingEnabled()) {
+    addCachedSubsequence(client, sizeBeforeCopy,
+                         m_newDisplayItemList.size() - 1);
+  }
+
+  m_nextItemToMatch = markers->end + 1;
+  // Items before |m_nextItemToMatch| have been copied so we don't need to index
+  // them.
+  if (m_nextItemToMatch > m_nextItemToIndex)
+    m_nextItemToIndex = m_nextItemToMatch;
 
   if (RuntimeEnabledFeatures::paintUnderInvalidationCheckingEnabled()) {
     // Return false to let the painter actually paint. We will check if the new
     // painting is the same as the cached one.
     return false;
   }
 
   return true;
 }
 
+PaintController::SubsequenceMarkers* PaintController::getSubsequenceMarkers(
+    const DisplayItemClient& client) {
+  auto result = m_currentCachedSubsequences.find(&client);
+  if (result == m_currentCachedSubsequences.end())
+    return nullptr;
+  return &result->value;
+}
+
+void PaintController::addCachedSubsequence(const DisplayItemClient& client,
+                                           unsigned start,
+                                           unsigned end) {
+  DCHECK(start <= end);
+  DCHECK(end < m_newDisplayItemList.size());
+  if (isCheckingUnderInvalidation()) {
+    SubsequenceMarkers* markers = getSubsequenceMarkers(client);
+    if (!markers) {
+      showSequenceUnderInvalidationError(
+          "under-invalidation : unexpected subsequence", client, start, end);
+      DCHECK(false);
+    }
+    if (markers->end - markers->start != end - start) {
+      showSequenceUnderInvalidationError(
+          "under-invalidation: new subsequence wrong length", client, start,
+          end);
+      DCHECK(false);
+    }
+  }
+
+  DCHECK(m_newCachedSubsequences.find(&client) ==
+         m_newCachedSubsequences.end());
+
+  m_newCachedSubsequences.insert(&client, SubsequenceMarkers(start, end));
+}
+
 bool PaintController::lastDisplayItemIsNoopBegin() const {
   if (m_newDisplayItemList.isEmpty())
     return false;
 
   const auto& lastDisplayItem = m_newDisplayItemList.last();
   return lastDisplayItem.isBegin() && !lastDisplayItem.drawsContent();
 }
 
 void PaintController::removeLastDisplayItem() {
   if (m_newDisplayItemList.isEmpty())
@@ skipping 25 matching lines @@
   if (RuntimeEnabledFeatures::slimmingPaintV2Enabled())
     m_newPaintChunks.decrementDisplayItemIndex();
 }
 
 const DisplayItem* PaintController::lastDisplayItem(unsigned offset) {
   if (offset < m_newDisplayItemList.size())
     return &m_newDisplayItemList[m_newDisplayItemList.size() - offset - 1];
   return nullptr;
 }
 
+#if CHECK_DISPLAY_ITEM_CLIENT_ALIVENESS
+void PaintController::beginShouldKeepAlive(const DisplayItemClient& client) {
+  if (!isSkippingCache()) {
+    // Mark the client shouldKeepAlive under this PaintController.
+    // The status will end after the new display items are committed.
+    client.beginShouldKeepAlive(this);
+
+    if (!m_currentSubsequenceClients.isEmpty()) {
+      // Mark the client shouldKeepAlive under the current subsequence.
+      // The status will end when the subsequence owner is invalidated or
+      // deleted.
+      client.beginShouldKeepAlive(m_currentSubsequenceClients.back());
+    }
+  }
+}
+#endif
+
 void PaintController::processNewItem(DisplayItem& displayItem) {
   DCHECK(!m_constructionDisabled);
 
 #if CHECK_DISPLAY_ITEM_CLIENT_ALIVENESS
-  if (!isSkippingCache()) {
-    if (displayItem.isCacheable()) {
-      // Mark the client shouldKeepAlive under this PaintController.
-      // The status will end after the new display items are committed.
-      displayItem.client().beginShouldKeepAlive(this);
-
-      if (!m_currentSubsequenceClients.isEmpty()) {
-        // Mark the client shouldKeepAlive under the current subsequence.
-        // The status will end when the subsequence owner is invalidated or
-        // deleted.
-        displayItem.client().beginShouldKeepAlive(
-            m_currentSubsequenceClients.back());
-      }
-    }
-
-    if (displayItem.getType() == DisplayItem::kSubsequence) {
-      m_currentSubsequenceClients.push_back(&displayItem.client());
-    } else if (displayItem.getType() == DisplayItem::kEndSubsequence) {
-      CHECK(m_currentSubsequenceClients.back() == &displayItem.client());
-      m_currentSubsequenceClients.pop_back();
-    }
+  if (displayItem.isCacheable()) {
+    beginShouldKeepAlive(displayItem.client());
   }
 #endif
 
   if (isSkippingCache())
     displayItem.setSkippedCache();
 
   if (RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
     size_t lastChunkIndex = m_newPaintChunks.lastChunkIndex();
     if (m_newPaintChunks.incrementDisplayItemIndex(displayItem)) {
       DCHECK(lastChunkIndex != m_newPaintChunks.lastChunkIndex());
       if (lastChunkIndex != kNotFound)
         generateChunkRasterInvalidationRects(
             m_newPaintChunks.paintChunkAt(lastChunkIndex));
     }
   }
 
 #if DCHECK_IS_ON()
   // Verify noop begin/end pairs have been removed.
   if (m_newDisplayItemList.size() >= 2 && displayItem.isEnd()) {
     const auto& beginDisplayItem =
         m_newDisplayItemList[m_newDisplayItemList.size() - 2];
     if (beginDisplayItem.isBegin() &&
-        beginDisplayItem.getType() != DisplayItem::kSubsequence &&
         !beginDisplayItem.drawsContent())
       DCHECK(!displayItem.isEndAndPairedWith(beginDisplayItem.getType()));
   }
 
   size_t index = findMatchingItemFromIndex(displayItem.getId(),
                                            m_newDisplayItemIndicesByClient,
                                            m_newDisplayItemList);
   if (index != kNotFound) {
 #ifndef NDEBUG
     showDebugData();
@@ skipping 155 matching lines @@
   if (RuntimeEnabledFeatures::paintUnderInvalidationCheckingEnabled())
     CHECK(false) << "Can't find cached display item";
 
   // We did not find the cached display item. This should be impossible, but may
   // occur if there is a bug in the system, such as under-invalidation,
   // incorrect cache checking or duplicate display ids. In this case, the caller
   // should fall back to repaint the display item.
   return kNotFound;
 }
 
-// Copies a cached subsequence from current list to the new list. On return,
-// |cachedItemIndex| points to the item after the EndSubsequence item of the
-// subsequence. When paintUnderInvaldiationCheckingEnabled() we'll not actually
+// Copies a cached subsequence from current list to the new list.
+// When paintUnderInvaldiationCheckingEnabled() we'll not actually
 // copy the subsequence, but mark the begin and end of the subsequence for
 // under-invalidation checking.
-void PaintController::copyCachedSubsequence(size_t& cachedItemIndex) {
+void PaintController::copyCachedSubsequence(size_t beginIndex,
+                                            size_t endIndex) {
   AutoReset<size_t> subsequenceBeginIndex(
       &m_currentCachedSubsequenceBeginIndexInNewList,
       m_newDisplayItemList.size());
   DisplayItem* cachedItem =
-      &m_currentPaintArtifact.getDisplayItemList()[cachedItemIndex];
-  DCHECK(cachedItem->getType() == DisplayItem::kSubsequence);
+      &m_currentPaintArtifact.getDisplayItemList()[beginIndex];
 
   if (RuntimeEnabledFeatures::paintUnderInvalidationCheckingEnabled()) {
     DCHECK(!isCheckingUnderInvalidation());
-    m_underInvalidationCheckingBegin = cachedItemIndex;
+    m_underInvalidationCheckingBegin = beginIndex;
     m_underInvalidationMessagePrefix =
         "(In cached subsequence of " + cachedItem->client().debugName() + ")";
   }
 
-  DisplayItem::Id endSubsequenceId(cachedItem->client(),
-                                   DisplayItem::kEndSubsequence);
   Vector<PaintChunk>::const_iterator cachedChunk;
   if (RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
     cachedChunk =
-        m_currentPaintArtifact.findChunkByDisplayItemIndex(cachedItemIndex);
+        m_currentPaintArtifact.findChunkByDisplayItemIndex(beginIndex);
     DCHECK(cachedChunk != m_currentPaintArtifact.paintChunks().end());
     updateCurrentPaintChunkProperties(
         cachedChunk->id ? &*cachedChunk->id : nullptr, cachedChunk->properties);
   } else {
     // Avoid uninitialized variable error on Windows.
     cachedChunk = m_currentPaintArtifact.paintChunks().begin();
   }
 
-  while (true) {
+  for (size_t currentIndex = beginIndex; currentIndex <= endIndex;
+       ++currentIndex) {
+    cachedItem = &m_currentPaintArtifact.getDisplayItemList()[currentIndex];
     DCHECK(cachedItem->hasValidClient());
 #if CHECK_DISPLAY_ITEM_CLIENT_ALIVENESS
     CHECK(cachedItem->client().isAlive());
 #endif
     ++m_numCachedNewItems;
-    bool metEndSubsequence = cachedItem->getId() == endSubsequenceId;
     if (!RuntimeEnabledFeatures::paintUnderInvalidationCheckingEnabled()) {
       if (RuntimeEnabledFeatures::slimmingPaintV2Enabled() &&
-          cachedItemIndex == cachedChunk->endIndex) {
+          currentIndex == cachedChunk->endIndex) {
         ++cachedChunk;
         DCHECK(cachedChunk != m_currentPaintArtifact.paintChunks().end());
         updateCurrentPaintChunkProperties(
             cachedChunk->id ? &*cachedChunk->id : nullptr,
             cachedChunk->properties);
       }
-      processNewItem(moveItemFromCurrentListToNewList(cachedItemIndex));
+      processNewItem(moveItemFromCurrentListToNewList(currentIndex));
       if (RuntimeEnabledFeatures::slimmingPaintV2Enabled())
         DCHECK((!m_newPaintChunks.lastChunk().id && !cachedChunk->id) ||
                m_newPaintChunks.lastChunk().matches(*cachedChunk));
     }
-
-    ++cachedItemIndex;
-    if (metEndSubsequence)
-      break;
-
-    // We should always be able to find the EndSubsequence display item.
-    DCHECK(cachedItemIndex <
-           m_currentPaintArtifact.getDisplayItemList().size());
-    cachedItem = &m_currentPaintArtifact.getDisplayItemList()[cachedItemIndex];
   }
 
   if (RuntimeEnabledFeatures::paintUnderInvalidationCheckingEnabled()) {
-    m_underInvalidationCheckingEnd = cachedItemIndex;
+    m_underInvalidationCheckingEnd = endIndex + 1;
     DCHECK(isCheckingUnderInvalidation());
   }
 }
 
 DISABLE_CFI_PERF
 static IntRect visualRectForDisplayItem(
     const DisplayItem& displayItem,
     const LayoutSize& offsetFromLayoutObject) {
   LayoutRect visualRect = displayItem.client().visualRect();
   visualRect.move(-offsetFromLayoutObject);
@@ skipping 11 matching lines @@
 
 DISABLE_CFI_PERF
 void PaintController::commitNewDisplayItems(
     const LayoutSize& offsetFromLayoutObject) {
   TRACE_EVENT2("blink,benchmark", "PaintController::commitNewDisplayItems",
                "current_display_list_size",
                (int)m_currentPaintArtifact.getDisplayItemList().size(),
                "num_non_cached_new_items",
                (int)m_newDisplayItemList.size() - m_numCachedNewItems);
   m_numCachedNewItems = 0;
-
   // These data structures are used during painting only.
   DCHECK(!isSkippingCache());
 #if DCHECK_IS_ON()
   m_newDisplayItemIndicesByClient.clear();
 #endif
 
   if (RuntimeEnabledFeatures::slimmingPaintV2Enabled() &&
       !m_newDisplayItemList.isEmpty())
     generateChunkRasterInvalidationRects(m_newPaintChunks.lastChunk());
 
   SkPictureGpuAnalyzer gpuAnalyzer;
 
   m_currentCacheGeneration =
       DisplayItemClient::CacheGenerationOrInvalidationReason::next();
+
+  m_newCachedSubsequences.swap(m_currentCachedSubsequences);
+  m_newCachedSubsequences.clear();
+  for (auto& item : m_currentCachedSubsequences) {
+    item.key->setDisplayItemsCached(m_currentCacheGeneration);
+#if CHECK_DISPLAY_ITEM_CLIENT_ALIVENESS
+    DisplayItemClient::endShouldKeepAliveAllClients(item.key);
+#endif
+  }
+
   Vector<const DisplayItemClient*> skippedCacheClients;
   for (const auto& item : m_newDisplayItemList) {
     // No reason to continue the analysis once we have a veto.
     if (gpuAnalyzer.suitableForGpuRasterization())
       item.analyzeForGpuRasterization(gpuAnalyzer);
 
     // TODO(wkorman): Only compute and append visual rect for drawings.
     m_newDisplayItemList.appendVisualRect(
         visualRectForDisplayItem(item, offsetFromLayoutObject));
 
@@ skipping 39 matching lines @@
     for (const auto& chunk : m_currentPaintArtifact.paintChunks()) {
       if (chunk.id && chunk.id->client.isJustCreated())
         chunk.id->client.clearIsJustCreated();
     }
   }
 
   // We'll allocate the initial buffer when we start the next paint.
   m_newDisplayItemList = DisplayItemList(0);
 
 #if CHECK_DISPLAY_ITEM_CLIENT_ALIVENESS
-  CHECK(m_currentSubsequenceClients.isEmpty());
   DisplayItemClient::endShouldKeepAliveAllClients(this);
 #endif
 
 #ifndef NDEBUG
   m_numSequentialMatches = 0;
   m_numOutOfOrderMatches = 0;
   m_numIndexedItems = 0;
 #endif
 }
 
@@ skipping 198 matching lines @@
   }
   LOG(INFO) << "new record:\n"
             << (newRecord ? recordAsDebugString(newRecord) : "None");
   LOG(INFO) << "old record:\n"
             << (oldRecord ? recordAsDebugString(oldRecord) : "None");
 
   showDebugData();
 #endif  // NDEBUG
 }
 
+void PaintController::showSequenceUnderInvalidationError(
+    const char* reason,
+    const DisplayItemClient& client,
+    int start,
+    int end) {
+  LOG(ERROR) << m_underInvalidationMessagePrefix << " " << reason;
+  LOG(ERROR) << "Subsequence client: " << client.debugName();
+#ifndef NDEBUG
+//  showDebugData();
+#else
+  LOG(ERROR) << "Run debug build to get more details.";
+#endif
+  LOG(ERROR) << "See http://crbug.com/619103.";
+}
+
 void PaintController::checkUnderInvalidation() {
   DCHECK(RuntimeEnabledFeatures::paintUnderInvalidationCheckingEnabled());
 
   if (!isCheckingUnderInvalidation())
     return;
 
   const DisplayItem& newItem = m_newDisplayItemList.last();
   size_t oldItemIndex = m_underInvalidationCheckingBegin +
                         m_skippedProbableUnderInvalidationCount;
   DisplayItem* oldItem =
@@ skipping 65 matching lines @@
                        showPaintRecords
                            ? (DisplayItemList::JsonOptions::ShowPaintRecords |
                               DisplayItemList::JsonOptions::ShowClientDebugName)
                            : DisplayItemList::JsonOptions::ShowClientDebugName)
                    ->toPrettyJSONString()
                    .utf8()
                    .data());
 }
 
 }  // namespace blink