Index initialization improvements for Simple Cache.

net/disk_cache/simple/simple_index_file.h

 // Copyright (c) 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 NET_DISK_CACHE_SIMPLE_SIMPLE_INDEX_FILE_H_
 #define NET_DISK_CACHE_SIMPLE_SIMPLE_INDEX_FILE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 79 matching lines @@
                            bool app_on_background);
 
   // Doom the entries specified in |entry_hashes|, calling |reply_callback|
   // with the result on the current thread when done.
   virtual void DoomEntrySet(scoped_ptr<std::vector<uint64> > entry_hashes,
                             const base::Callback<void(int)>& reply_callback);
 
  private:
   friend class WrappedSimpleIndexFile;
 
+  // When loading the entries from disk, add this many extra hash buckets to
+  // prevent reallocation on the IO thread when merging in new live entries.
+  static const int kExtraSizeForMerge = 512;
+
   // Synchronous (IO performing) implementation of LoadIndexEntries.
   static void SyncLoadIndexEntries(base::Time cache_last_modified,
                                    const base::FilePath& cache_directory,
                                    const base::FilePath& index_file_path,
                                    SimpleIndexLoadResult* out_result);
 
   // Load the index file from disk returning an EntrySet. Upon failure, returns
   // NULL.
   static void SyncLoadFromDisk(const base::FilePath& index_filename,
                                SimpleIndexLoadResult* out_result);
@@ skipping 33 matching lines @@
   static const char kIndexFileName[];
   static const char kTempIndexFileName[];
 
   DISALLOW_COPY_AND_ASSIGN(SimpleIndexFile);
 };
 
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_SIMPLE_SIMPLE_INDEX_FILE_H_