Disk cache: Read the index and data_0 files in a single...

net/disk_cache/block_files.h

 // Copyright (c) 2010 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.
 
 // See net/disk_cache/disk_cache.h for the public interface.
 
 #ifndef NET_DISK_CACHE_BLOCK_FILES_H__
 #define NET_DISK_CACHE_BLOCK_FILES_H__
 
 #include <vector>
@@ skipping 28 matching lines @@
 
   // Removes an entry from the block files. If deep is true, the storage is zero
   // filled; otherwise the entry is removed but the data is not altered (must be
   // already zeroed).
   void DeleteBlock(Addr address, bool deep);
 
   // Close all the files and set the internal state to be initializad again. The
   // cache is being purged.
   void CloseFiles();
 
+  // Sends UMA stats.
+  void ReportStats();
+
  private:
   // Set force to true to overwrite the file if it exists.
   bool CreateBlockFile(int index, FileType file_type, bool force);
   bool OpenBlockFile(int index);
 
   // Attemp to grow this file. Fails if the file cannot be extended anymore.
   bool GrowBlockFile(MappedFile* file, BlockFileHeader* header);
 
   // Returns the appropriate file to use for a new block.
   MappedFile* FileForNewBlock(FileType block_type, int block_count);
 
   // Returns the next block file on this chain, creating new files if needed.
   MappedFile* NextFile(const MappedFile* file);
 
   // Creates an empty block file and returns its index.
   int CreateNextBlockFile(FileType block_type);
 
   // Removes a chained block file that is now empty.
   void RemoveEmptyFile(FileType block_type);
 
   // Restores the header of a potentially inconsistent file.
   bool FixBlockFileHeader(MappedFile* file);
 
+  // Retrieves stats for the given file index.
+  void GetFileStats(int index, int* used_count, int* load);
+
   // Returns the filename for a given file index.
   FilePath Name(int index);
 
   bool init_;
   char* zero_buffer_;  // Buffer to speed-up cleaning deleted entries.
   FilePath path_;  // Path to the backing folder.
   std::vector<MappedFile*> block_files_;  // The actual files.
 
   FRIEND_TEST(DiskCacheTest, BlockFiles_ZeroSizeFile);
   FRIEND_TEST(DiskCacheTest, BlockFiles_InvalidFile);
+  FRIEND_TEST(DiskCacheTest, BlockFiles_Stats);
 
   DISALLOW_COPY_AND_ASSIGN(BlockFiles);
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_BLOCK_FILES_H__