Disk Cache: Make Stats independent of the backend implementation.

net/disk_cache/stats.h

Index: net/disk_cache/stats.h
===================================================================
--- net/disk_cache/stats.h	(revision 201602)
+++ net/disk_cache/stats.h	(working copy)
@@ -9,6 +9,7 @@
 #include <vector>
 
 #include "base/basictypes.h"
+#include "net/disk_cache/addr.h"
 #include "net/disk_cache/stats_histogram.h"
 
 namespace base {
@@ -17,8 +18,6 @@
 
 namespace disk_cache {
 
-class BackendImpl;
-
 typedef std::vector<std::pair<std::string, std::string> > StatsItems;
 
 // This class stores cache-specific usage information, for tunning purposes.
@@ -55,8 +54,15 @@
   Stats();
   ~Stats();
 
-  bool Init(BackendImpl* backend, uint32* storage_addr);
+  // Initializes this object with the provided |data| comming from disk.

[gavinp, 2013/05/23 15:32:33]

Spelling, but also I think the grammar is a bit awkward.

How about:

// Initialize |*this| with |data| from disk.

Perhaps with prose instead of |*this| ?

[rvargas (doing something else), 2013/05/23 19:39:43]

Done.

+  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);
 
@@ -73,8 +79,8 @@
   // Returns the lower bound of the space used by entries bigger than 512 KB.
   int GetLargeEntriesSize();
 
-  // Saves the stats to disk.
-  void Store();
+  // Writes the stats into |data|, to be stored at the given cache address.
+  bool 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.
@@ -85,8 +91,7 @@
   int GetStatsBucket(int32 size);
   int GetRatio(Counters hit, Counters miss) const;
 
-  BackendImpl* backend_;
-  uint32 storage_addr_;
+  Addr storage_addr_;
   int data_sizes_[kDataSizesLength];
   int64 counters_[MAX_COUNTER];
   StatsHistogram* size_histogram_;