Add SimpleCache index file heuristics

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 "base/basictypes.h"
@@ skipping 50 matching lines @@
   // Returns a scoped_ptr for a newly allocated Pickle containing the serialized
   // data to be written to a file.
   static scoped_ptr<Pickle> Serialize(
       const SimpleIndexFile::IndexMetadata& index_metadata,
       const SimpleIndex::EntrySet& entries);
 
   // Write the serialized data from |pickle| into the index file.
   static void WriteToDisk(const base::FilePath& index_filename,
                           const Pickle& pickle);
 
+  // Using mtime of the file and the path, it detects if the index file is

[gavinp, 2013/04/19 11:30:17]

// Using the mtime of the file and its mtime, detects if the index file is
stale.

[felipeg, 2013/04/19 12:20:29]

Done.

+  // stale.
+  static bool IsIndexFileStale(const base::FilePath& index_filename);
+
  private:
   FRIEND_TEST_ALL_PREFIXES(SimpleIndexFileTest, Serialize);
 
   // Deserialize() is separate from LoadFromDisk() for easier testing.
   static scoped_ptr<SimpleIndex::EntrySet> Deserialize(const char* data,
                                                        int data_len);
 
   struct PickleHeader : public Pickle::Header {
     uint32 crc;
   };
 
   DISALLOW_COPY_AND_ASSIGN(SimpleIndexFile);
 };
 
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_SIMPLE_SIMPLE_INDEX_FILE_H_