Move CachedRanges out and add support for checksum.

base/metrics/histogram.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.
 
 // Histogram is an object that aggregates statistics, and can summarize them in
 // various forms, including ASCII graphical, HTML, and numerically (as a
 // vector of numbers corresponding to each of the aggregating buckets).
 
 // It supports calls to accumulate either time intervals (which are processed
 // as integral number of milliseconds), or arbitrary integral units.
@@ skipping 31 matching lines @@
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/atomicops.h"
 #include "base/base_export.h"
 #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"
 
 class Pickle;
 class PickleIterator;
 
 namespace base {
 
 class Lock;
 //------------------------------------------------------------------------------
@@ skipping 249 matching lines @@
             boundary_value + 1, base::Histogram::kUmaTargetedHistogramFlag))
 
 #define UMA_HISTOGRAM_CUSTOM_ENUMERATION(name, sample, custom_ranges) \
     STATIC_HISTOGRAM_POINTER_BLOCK(name, Add(sample), \
         base::CustomHistogram::FactoryGet(name, custom_ranges, \
             base::Histogram::kUmaTargetedHistogramFlag))
 
 //------------------------------------------------------------------------------
 
 class BooleanHistogram;
-class CachedRanges;
+class BucketRanges;
 class CustomHistogram;
 class Histogram;
 class LinearHistogram;
 
 class BASE_EXPORT Histogram : public HistogramBase {
  public:
   // Initialize maximum number of buckets in histograms as 16,384.
   static const size_t kBucketCount_MAX;
 
   typedef std::vector<Count> Counts;
@@ skipping 129 matching lines @@
   }
 
   void AddSampleSet(const SampleSet& sample);
 
   // This method is an interface, used only by LinearHistogram.
   virtual void SetRangeDescriptions(const DescriptionPair descriptions[]);
 
   // 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..
   // 0x8000 means print ranges in hex.
   void SetFlags(Flags flags) { flags_ = static_cast<Flags> (flags_ | flags); }
   void ClearFlags(Flags flags) { flags_ = static_cast<Flags>(flags_ & ~flags); }
   int flags() const { return flags_; }
 
   // Convenience methods for serializing/deserializing the histograms.
   // Histograms from Renderer process are serialized and sent to the browser.
@@ skipping 20 matching lines @@
 
   //----------------------------------------------------------------------------
   // Accessors for factory constuction, serialization and testing.
   //----------------------------------------------------------------------------
   virtual ClassType histogram_type() const;
   Sample declared_min() const { return declared_min_; }
   Sample declared_max() const { return declared_max_; }
   virtual Sample ranges(size_t i) const;
   uint32 range_checksum() const { return range_checksum_; }
   virtual size_t bucket_count() const;
-  CachedRanges* cached_ranges() const { return cached_ranges_; }
-  void set_cached_ranges(CachedRanges* cached_ranges) {
-    cached_ranges_ = cached_ranges;
+  BucketRanges* bucket_ranges() const { return bucket_ranges_; }
+  void set_bucket_ranges(BucketRanges* bucket_ranges) {
+    bucket_ranges_ = bucket_ranges;
   }
   // Snapshot the current complete set of sample data.
   // Override with atomic/locked snapshot if needed.
   virtual void SnapshotSample(SampleSet* sample) const;
 
   virtual bool HasConstructorArguments(Sample minimum, Sample maximum,
                                        size_t bucket_count);
 
   virtual bool HasConstructorTimeDeltaArguments(TimeDelta minimum,
                                                 TimeDelta maximum,
                                                 size_t bucket_count);
   // Return true iff the range_checksum_ matches current |ranges_| vector in
-  // |cached_ranges_|.
+  // |bucket_ranges_|.
   bool HasValidRangeChecksum() const;
 
  protected:
   Histogram(const std::string& name, Sample minimum,
             Sample maximum, size_t bucket_count);
   Histogram(const std::string& name, TimeDelta minimum,
             TimeDelta maximum, size_t bucket_count);
 
   virtual ~Histogram();
 
   // Serialize the histogram's ranges to |*pickle|, returning true on success.
   // Most subclasses can leave this no-op implementation, but some will want to
   // override it, especially if the ranges cannot be re-derived from other
   // serialized parameters.
   virtual bool SerializeRanges(Pickle* pickle) const;
 
-  // Initialize ranges_ mapping in cached_ranges_.
+  // Initialize ranges_ mapping in bucket_ranges_.
   void InitializeBucketRange();
 
   // Method to override to skip the display of the i'th bucket if it's empty.
   virtual bool PrintEmptyBucket(size_t index) const;
 
   //----------------------------------------------------------------------------
   // Methods to override to create histogram with different bucket widths.
   //----------------------------------------------------------------------------
   // Find bucket to increment for sample value.
   virtual size_t BucketIndex(Sample value) const;
@@ skipping 12 matching lines @@
   // Methods to override to create thread safe histogram.
   //----------------------------------------------------------------------------
   // Update all our internal data, including histogram
   virtual void Accumulate(Sample value, Count count, size_t index);
 
   //----------------------------------------------------------------------------
   // Accessors for derived classes.
   //----------------------------------------------------------------------------
   void SetBucketRange(size_t i, Sample value);
 
-  // Validate that ranges_ in cached_ranges_ was created sensibly (top and
+  // Validate that ranges_ in bucket_ranges_ was created sensibly (top and
   // bottom range values relate properly to the declared_min_ and
   // declared_max_).
   bool ValidateBucketRanges() const;
 
   virtual uint32 CalculateRangeChecksum() const;
 
  private:
   // Allow tests to corrupt our innards for testing purposes.
   FRIEND_TEST_ALL_PREFIXES(HistogramTest, CorruptBucketBounds);
   FRIEND_TEST_ALL_PREFIXES(HistogramTest, CorruptSampleCounts);
   FRIEND_TEST_ALL_PREFIXES(HistogramTest, Crc32SampleHash);
   FRIEND_TEST_ALL_PREFIXES(HistogramTest, Crc32TableTest);
 
   friend class StatisticsRecorder;  // To allow it to delete duplicates.
 
   // Post constructor initialization.
   void Initialize();
 
   // Checksum function for accumulating range values into a checksum.
   static uint32 Crc32(uint32 sum, Sample range);
 
   //----------------------------------------------------------------------------
   // 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;
 
   // Write a common header message describing this histogram.
   void WriteAsciiHeader(const SampleSet& snapshot,
                         Count sample_count, std::string* output) const;
 
   // Write information about previous, current, and next buckets.
   // Information such as cumulative percentage, etc.
   void WriteAsciiBucketContext(const int64 past, const Count current,
@@ skipping 18 matching lines @@
   Sample declared_min_;  // Less than this goes into counts_[0]
   Sample declared_max_;  // Over this goes into counts_[bucket_count_ - 1].
   size_t bucket_count_;  // Dimension of counts_[].
 
   // Flag the histogram for recording by UMA via metric_services.h.
   Flags flags_;
 
   // 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 cached_ranges_ is bucket_count + 1.
-  CachedRanges* cached_ranges_;
+  // The dimension of ranges_ in bucket_ranges_ is bucket_count + 1.
+  BucketRanges* bucket_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
   // have been corrupted.
   uint32 range_checksum_;
 
   // Finally, provide the state that changes with the addition of each new
   // sample.
   SampleSet sample_;
 
@@ skipping 29 matching lines @@
   virtual void SetRangeDescriptions(
       const DescriptionPair descriptions[]) OVERRIDE;
 
  protected:
   LinearHistogram(const std::string& name, Sample minimum,
                   Sample maximum, size_t bucket_count);
 
   LinearHistogram(const std::string& name, TimeDelta minimum,
                   TimeDelta maximum, size_t bucket_count);
 
-  // Initialize ranges_ mapping in cached_ranges_.
+  // Initialize ranges_ mapping in bucket_ranges_.
   void InitializeBucketRange();
   virtual double GetBucketSize(Count current, size_t i) const OVERRIDE;
 
   // If we have a description for a bucket, then return that.  Otherwise
   // let parent class provide a (numeric) description.
   virtual const std::string GetAsciiBucketRange(size_t i) const OVERRIDE;
 
   // Skip printing of name for numeric range if we have a name (and if this is
   // an empty bucket).
   virtual bool PrintEmptyBucket(size_t index) const OVERRIDE;
@@ skipping 51 matching lines @@
   static bool DeserializeRanges(PickleIterator* iter,
                                 std::vector<Histogram::Sample>* ranges);
 
 
  protected:
   CustomHistogram(const std::string& name,
                   const std::vector<Sample>& custom_ranges);
 
   virtual bool SerializeRanges(Pickle* pickle) const OVERRIDE;
 
-  // Initialize ranges_ mapping in cached_ranges_.
+  // Initialize ranges_ mapping in bucket_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_