Client side display item cache flag

third_party/WebKit/Source/platform/graphics/paint/PaintController.h

 // 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.
 
 #ifndef PaintController_h
 #define PaintController_h
 
 #include "platform/PlatformExport.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/geometry/IntRect.h"
@@ skipping 145 matching lines @@
     {
         ASSERT(RuntimeEnabledFeatures::slimmingPaintV2Enabled());
         m_trackedPaintInvalidationObjects = nullptr;
     }
     Vector<String> trackedPaintInvalidationObjects()
     {
         ASSERT(RuntimeEnabledFeatures::slimmingPaintV2Enabled());
         return m_trackedPaintInvalidationObjects ? *m_trackedPaintInvalidationObjects : Vector<String>();
     }
 
-    bool clientHasCheckedPaintInvalidation(const DisplayItemClient& client) const
-    {
-        return m_clientsCheckedPaintInvalidation.contains(&client);
-    }
-    void setClientHasCheckedPaintInvalidation(const DisplayItemClient& client)
-    {
-        m_clientsCheckedPaintInvalidation.add(&client);
-    }
-
 #if ENABLE(ASSERT)
     void assertDisplayItemClientsAreLive();
 #endif
 
+    bool canUseClientCacheStatus() const { return m_canUseClientCacheStatus; }
+    void setCanUseClientCacheStatus(bool b) { m_canUseClientCacheStatus = b; }
+
+    unsigned currentCacheGeneration() const { return m_currentCacheGeneration; }
+
 protected:
     PaintController()
         : m_newDisplayItemList(kInitialDisplayItemListCapacityBytes)
-        , m_validlyCachedClientsDirty(false)
         , m_constructionDisabled(false)
         , m_subsequenceCachingDisabled(false)
         , m_textPainted(false)
         , m_imagePainted(false)
         , m_skippingCacheCount(0)
         , m_numCachedNewItems(0)
-        , m_nextScope(1) { }
+        , m_nextScope(1)
+        , m_canUseClientCacheStatus(false)
+        , m_currentCacheGeneration(DisplayItemClient::kInvalidCacheGeneration)
+    { }
 
 private:
     // Set new item state (scopes, cache skipping, etc) for a new item.
     void processNewItem(DisplayItem&);
 
-    void updateValidlyCachedClientsIfNeeded() const;
-
 #ifndef NDEBUG
     WTF::String displayItemListAsDebugString(const DisplayItemList&) const;
 #endif
 
     // Indices into PaintList of all DrawingDisplayItems and BeginSubsequenceDisplayItems of each client.
     // Temporarily used during merge to find out-of-order display items.
     using DisplayItemIndicesByClientMap = HashMap<const DisplayItemClient*, Vector<size_t>>;
 
     static size_t findMatchingItemFromIndex(const DisplayItem::Id&, const DisplayItemIndicesByClientMap&, const DisplayItemList&);
     static void addItemToIndexIfNeeded(const DisplayItem&, size_t index, DisplayItemIndicesByClientMap&);
 
     struct OutOfOrderIndexContext;
     DisplayItemList::iterator findOutOfOrderCachedItem(const DisplayItem::Id&, OutOfOrderIndexContext&);
     DisplayItemList::iterator findOutOfOrderCachedItemForward(const DisplayItem::Id&, OutOfOrderIndexContext&);
     void copyCachedSubsequence(const DisplayItemList& currentList, DisplayItemList::iterator& currentIt, DisplayItemList& updatedList);
 
 #if ENABLE(ASSERT)
     // The following two methods are for checking under-invalidations
     // (when RuntimeEnabledFeatures::slimmingPaintUnderInvalidationCheckingEnabled).
     void checkUnderInvalidation(DisplayItemList::iterator& newIt, DisplayItemList::iterator& currentIt);
     void checkCachedDisplayItemIsUnchanged(const char* messagePrefix, const DisplayItem& newItem, const DisplayItem& oldItem);
     void checkNoRemainingCachedDisplayItems();
 #endif
 
     void commitNewDisplayItemsInternal(const LayoutSize& offsetFromLayoutObject);
 
+    static unsigned nextCacheGeneration();
+    void updateCacheGeneration();
+
     // The last complete paint artifact.
     // In SPv2, this includes paint chunks as well as display items.
     PaintArtifact m_currentPaintArtifact;
 
     // Data being used to build the next paint artifact.
     DisplayItemList m_newDisplayItemList;
     PaintChunker m_newPaintChunks;
 
-    // Contains all clients having valid cached paintings if updated.
-    // It's lazily updated in updateValidlyCachedClientsIfNeeded().
-    // TODO(wangxianzhu): In the future we can replace this with client-side repaint flags
-    // to avoid the cost of building and querying the hash table.
-    mutable HashSet<const DisplayItemClient*> m_validlyCachedClients;
-    mutable bool m_validlyCachedClientsDirty;
-
-    // Used during painting. Contains clients that have checked paint invalidation and
-    // are known to be valid.
-    // TODO(wangxianzhu): Use client side flag to avoid const of hash table.
-    HashSet<const DisplayItemClient*> m_clientsCheckedPaintInvalidation;
-
 #if ENABLE(ASSERT)
     // Set of clients which had paint offset changes since the last commit. This is used for
     // ensuring paint offsets are only updated once and are the same in all phases.
     HashSet<const DisplayItemClient*> m_clientsWithPaintOffsetInvalidations;
 #endif
 
     // Allow display item construction to be disabled to isolate the costs of construction
     // in performance metrics.
     bool m_constructionDisabled;
 
@@ skipping 15 matching lines @@
     // Record the debug names of invalidated clients for assertion and debugging.
     Vector<String> m_invalidations;
 
     // This is used to check duplicated ids during add(). We could also check
     // during commitNewDisplayItems(), but checking during add() helps developer
     // easily find where the duplicated ids are from.
     DisplayItemIndicesByClientMap m_newDisplayItemIndicesByClient;
 #endif
 
     OwnPtr<Vector<String>> m_trackedPaintInvalidationObjects;
+
+    bool m_canUseClientCacheStatus;
+    unsigned m_currentCacheGeneration;
 };
 
 } // namespace blink
 
 #endif // PaintController_h