sync: Count nodes more efficiently

sync/syncable/directory.h

 // Copyright 2013 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 SYNC_SYNCABLE_DIRECTORY_H_
 #define SYNC_SYNCABLE_DIRECTORY_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 303 matching lines @@
   // children.
   bool GetChildHandlesById(BaseTransaction*, const Id& parent_id,
       ChildHandles* result);
 
   // Returns the child meta handles (even those for deleted/unlinked
   // nodes) for given meta handle.  Clears |result| if there are no
   // children.
   bool GetChildHandlesByHandle(BaseTransaction*, int64 handle,
       ChildHandles* result);
 
+  // Counts all items under the given node, including the node itself.
+  int GetTotalNodeCount(BaseTransaction*, EntryKernel* kernel_) const;
+
   // Returns true iff |id| has children.
   bool HasChildren(BaseTransaction* trans, const Id& id);
 
   // Find the first child in the positional ordering under a parent,
   // and fill in |*first_child_id| with its id.  Fills in a root Id if
   // parent has no children.  Returns true if the first child was
   // successfully found, or false if an error was encountered.
   Id GetFirstChildId(BaseTransaction* trans, const EntryKernel* parent);
 
   // These functions allow one to fetch the next or previous item under
@@ skipping 113 matching lines @@
   // For new entry creation only
   bool InsertEntry(WriteTransaction* trans,
                    EntryKernel* entry, ScopedKernelLock* lock);
   bool InsertEntry(WriteTransaction* trans, EntryKernel* entry);
 
   // Used by CheckTreeInvariants
   void GetAllMetaHandles(BaseTransaction* trans, MetahandleSet* result);
   bool SafeToPurgeFromMemory(WriteTransaction* trans,
                              const EntryKernel* const entry) const;
 
+  // A helper used by GetTotalNodeCount.
+  void GetChildSetForKernel(
+      BaseTransaction*,
+      EntryKernel* kernel_,
+      std::deque<const OrderedChildSet*>* child_sets) const;
+
   Directory& operator = (const Directory&);
 
  public:
   // These contain all items, including IS_DEL items.
   typedef Index<MetahandleIndexer>::Set MetahandlesIndex;
   typedef Index<IdIndexer>::Set IdsIndex;
 
   // Contains both deleted and existing entries with tags.
   // We can't store only existing tags because the client would create
   // items that had a duplicated ID in the end, resulting in a DB key
@@ skipping 109 matching lines @@
 
   // Maintain deleted entries not in |kernel_| until it's verified that they
   // are deleted in native models as well.
   scoped_ptr<DeleteJournal> delete_journal_;
 };
 
 }  // namespace syncable
 }  // namespace syncer
 
 #endif // SYNC_SYNCABLE_DIRECTORY_H_