Reorganize net/disk_cache into backend specific directories.

net/disk_cache/stats.h

-// Copyright (c) 2012 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_STATS_H_
-#define NET_DISK_CACHE_STATS_H_
-
-#include <string>
-#include <vector>
-
-#include "base/basictypes.h"
-#include "net/disk_cache/addr.h"
-#include "net/disk_cache/stats_histogram.h"
-
-namespace base {
-class HistogramSamples;
-}  // namespace base
-
-namespace disk_cache {
-
-typedef std::vector<std::pair<std::string, std::string> > StatsItems;
-
-// This class stores cache-specific usage information, for tunning purposes.
-class Stats {
- public:
-  static const int kDataSizesLength = 28;
-  enum Counters {
-    MIN_COUNTER = 0,
-    OPEN_MISS = MIN_COUNTER,
-    OPEN_HIT,
-    CREATE_MISS,
-    CREATE_HIT,
-    RESURRECT_HIT,
-    CREATE_ERROR,
-    TRIM_ENTRY,
-    DOOM_ENTRY,
-    DOOM_CACHE,
-    INVALID_ENTRY,
-    OPEN_ENTRIES,  // Average number of open entries.
-    MAX_ENTRIES,  // Maximum number of open entries.
-    TIMER,
-    READ_DATA,
-    WRITE_DATA,
-    OPEN_RANKINGS,  // An entry has to be read just to modify rankings.
-    GET_RANKINGS,  // We got the ranking info without reading the whole entry.
-    FATAL_ERROR,
-    LAST_REPORT,  // Time of the last time we sent a report.
-    LAST_REPORT_TIMER,  // Timer count of the last time we sent a report.
-    DOOM_RECENT,  // The cache was partially cleared.
-    UNUSED,  // Was: ga.js was evicted from the cache.
-    MAX_COUNTER
-  };
-
-  Stats();
-  ~Stats();
-
-  // Initializes this object with |data| from disk.
-  bool Init(void* data, int num_bytes, Addr address);
-
-  // Generates a size distribution histogram.
-  void InitSizeHistogram();
-
-  // Returns the number of bytes needed to store the stats on disk.
-  int StorageSize();
-
-  // Tracks changes to the stoage space used by an entry.
-  void ModifyStorageStats(int32 old_size, int32 new_size);
-
-  // Tracks general events.
-  void OnEvent(Counters an_event);
-  void SetCounter(Counters counter, int64 value);
-  int64 GetCounter(Counters counter) const;
-
-  void GetItems(StatsItems* items);
-  int GetHitRatio() const;
-  int GetResurrectRatio() const;
-  void ResetRatios();
-
-  // Returns the lower bound of the space used by entries bigger than 512 KB.
-  int GetLargeEntriesSize();
-
-  // Writes the stats into |data|, to be stored at the given cache address.
-  // Returns the number of bytes copied.
-  int SerializeStats(void* data, int num_bytes, Addr* address);
-
-  // Support for StatsHistograms. Together, these methods allow StatsHistograms
-  // to take a snapshot of the data_sizes_ as the histogram data.
-  int GetBucketRange(size_t i) const;
-  void Snapshot(base::HistogramSamples* samples) const;
-
- private:
-  int GetStatsBucket(int32 size);
-  int GetRatio(Counters hit, Counters miss) const;
-
-  Addr storage_addr_;
-  int data_sizes_[kDataSizesLength];
-  int64 counters_[MAX_COUNTER];
-  StatsHistogram* size_histogram_;
-
-  DISALLOW_COPY_AND_ASSIGN(Stats);
-};
-
-}  // namespace disk_cache
-
-#endif  // NET_DISK_CACHE_STATS_H_