Revert 148055 - Move CachedRanges out and add support for checksum.

base/metrics/histogram.h

Index: base/metrics/histogram.h
===================================================================
--- base/metrics/histogram.h	(revision 148059)
+++ base/metrics/histogram.h	(working copy)
@@ -49,7 +49,6 @@
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
 #include "base/logging.h"
-#include "base/metrics/bucket_ranges.h"
 #include "base/metrics/histogram_base.h"
 #include "base/time.h"
 
@@ -319,7 +318,7 @@
 //------------------------------------------------------------------------------
 
 class BooleanHistogram;
-class BucketRanges;
+class CachedRanges;
 class CustomHistogram;
 class Histogram;
 class LinearHistogram;
@@ -469,6 +468,9 @@
   // The following methods provide graphical histogram displays.
   virtual void WriteHTMLGraph(std::string* output) const OVERRIDE;
   virtual void WriteAscii(std::string* output) const OVERRIDE;
+  void WriteAsciiImpl(bool graph_it,
+                      const std::string& newline,
+                      std::string* output) const;
 
   // Support generic flagging of Histograms.
   // 0x1 Currently used to mark this histogram to be recorded by UMA..
@@ -509,9 +511,9 @@
   virtual Sample ranges(size_t i) const;
   uint32 range_checksum() const { return range_checksum_; }
   virtual size_t bucket_count() const;
-  BucketRanges* bucket_ranges() const { return bucket_ranges_; }
-  void set_bucket_ranges(BucketRanges* bucket_ranges) {
-    bucket_ranges_ = bucket_ranges;
+  CachedRanges* cached_ranges() const { return cached_ranges_; }
+  void set_cached_ranges(CachedRanges* cached_ranges) {
+    cached_ranges_ = cached_ranges;
   }
   // Snapshot the current complete set of sample data.
   // Override with atomic/locked snapshot if needed.
@@ -524,7 +526,7 @@
                                                 TimeDelta maximum,
                                                 size_t bucket_count);
   // Return true iff the range_checksum_ matches current |ranges_| vector in
-  // |bucket_ranges_|.
+  // |cached_ranges_|.
   bool HasValidRangeChecksum() const;
 
  protected:
@@ -541,7 +543,7 @@
   // serialized parameters.
   virtual bool SerializeRanges(Pickle* pickle) const;
 
-  // Initialize ranges_ mapping in bucket_ranges_.
+  // Initialize ranges_ mapping in cached_ranges_.
   void InitializeBucketRange();
 
   // Method to override to skip the display of the i'th bucket if it's empty.
@@ -574,7 +576,7 @@
   //----------------------------------------------------------------------------
   void SetBucketRange(size_t i, Sample value);
 
-  // Validate that ranges_ in bucket_ranges_ was created sensibly (top and
+  // Validate that ranges_ in cached_ranges_ was created sensibly (top and
   // bottom range values relate properly to the declared_min_ and
   // declared_max_).
   bool ValidateBucketRanges() const;
@@ -599,10 +601,6 @@
   //----------------------------------------------------------------------------
   // Helpers for emitting Ascii graphic.  Each method appends data to output.
 
-  void WriteAsciiImpl(bool graph_it,
-                      const std::string& newline,
-                      std::string* output) const;
-
   // Find out how large the (graphically) the largest bucket will appear to be.
   double GetPeakBucketSize(const SampleSet& snapshot) const;
 
@@ -641,8 +639,8 @@
   // For each index, show the least value that can be stored in the
   // corresponding bucket. We also append one extra element in this array,
   // containing kSampleType_MAX, to make calculations easy.
-  // The dimension of ranges_ in bucket_ranges_ is bucket_count + 1.
-  BucketRanges* bucket_ranges_;
+  // The dimension of ranges_ in cached_ranges_ is bucket_count + 1.
+  CachedRanges* cached_ranges_;
 
   // For redundancy, we store a checksum of all the sample ranges when ranges
   // are generated.  If ever there is ever a difference, then the histogram must
@@ -692,7 +690,7 @@
   LinearHistogram(const std::string& name, TimeDelta minimum,
                   TimeDelta maximum, size_t bucket_count);
 
-  // Initialize ranges_ mapping in bucket_ranges_.
+  // Initialize ranges_ mapping in cached_ranges_.
   void InitializeBucketRange();
   virtual double GetBucketSize(Count current, size_t i) const OVERRIDE;
 
@@ -764,13 +762,51 @@
 
   virtual bool SerializeRanges(Pickle* pickle) const OVERRIDE;
 
-  // Initialize ranges_ mapping in bucket_ranges_.
+  // Initialize ranges_ mapping in cached_ranges_.
   void InitializedCustomBucketRange(const std::vector<Sample>& custom_ranges);
   virtual double GetBucketSize(Count current, size_t i) const OVERRIDE;
 
   DISALLOW_COPY_AND_ASSIGN(CustomHistogram);
 };
 
+// CachedRanges stores the Ranges vector. Histograms that have same Ranges
+// vector will use the same CachedRanges object.
+class BASE_EXPORT CachedRanges {
+ public:
+  typedef std::vector<Histogram::Sample> Ranges;
+
+  CachedRanges(size_t bucket_count, int initial_value);
+  ~CachedRanges();
+
+  //----------------------------------------------------------------------------
+  // Accessors methods for ranges_ and range_checksum_.
+  //----------------------------------------------------------------------------
+  size_t size() const { return ranges_.size(); }
+  Histogram::Sample ranges(size_t i) const { return ranges_[i]; }
+  void SetBucketRange(size_t i, Histogram::Sample value);
+  uint32 range_checksum(uint32 checksum) const { return range_checksum_; }
+  void SetRangeChecksum(uint32 checksum) { range_checksum_ = checksum; }
+
+  // Return true iff |other| object has same ranges_ as |this| object's ranges_.
+  bool Equals(CachedRanges* other) const;
+
+ private:
+  // Allow tests to corrupt our innards for testing purposes.
+  FRIEND_TEST_ALL_PREFIXES(HistogramTest, CorruptBucketBounds);
+
+  // A monotonically increasing list of values which determine which bucket to
+  // put a sample into.  For each index, show the smallest sample that can be
+  // added to the corresponding bucket.
+  Ranges ranges_;
+
+  // Checksum for the conntents of ranges_.  Used to detect random over-writes
+  // of our data, and to quickly see if some other CachedRanges instance is
+  // possibly Equal() to this instance.
+  uint32 range_checksum_;
+
+  DISALLOW_COPY_AND_ASSIGN(CachedRanges);
+};
+
 }  // namespace base
 
 #endif  // BASE_METRICS_HISTOGRAM_H_