1 // Copyright 2013 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef BASE_METRICS_HISTOGRAM_DELTA_SERIALIZATION_H_ 6 #define BASE_METRICS_HISTOGRAM_DELTA_SERIALIZATION_H_ 7 8 #include <string> 9 #include <vector> 10 11 #include "base/base_export.h" 12 #include "base/basictypes.h" 13 #include "base/memory/scoped_ptr.h" 14 #include "base/metrics/histogram_flattener.h" 15 #include "base/metrics/histogram_snapshot_manager.h" 16 17 namespace base { 18 19 class HistogramBase; 20 21 // Serializes and restores histograms deltas. 22 class BASE_EXPORT HistogramDeltaSerialization : public HistogramFlattener { 23 public: 24 // |caller_name| is string used in histograms for counting inconsistencies. 25 explicit HistogramDeltaSerialization(const std::string& caller_name); 26 virtual ~HistogramDeltaSerialization(); 27 28 // Computes deltas in histogram bucket counts relative to the previous call to 29 // this method. Stores the deltas in serialized form into |serialized_deltas|. 30 // If |serialized_deltas| is NULL, no data is serialized, though the next call 31 // will compute the deltas relative to this one. 32 void PrepareAndSerializeDeltas(std::vector<std::string>* serialized_deltas); 33 34 // Deserialize deltas and add samples to corresponding histograms, creating 35 // them if necessary. Silently ignores errors in |serialized_deltas|. 36 static void DeserializeAndAddSamples( 37 const std::vector<std::string>& serialized_deltas); 38 39 private: 40 // HistogramFlattener implementation. 41 virtual void RecordDelta(const HistogramBase& histogram, 42 const HistogramSamples& snapshot) OVERRIDE; 43 virtual void InconsistencyDetected( 44 HistogramBase::Inconsistency problem) OVERRIDE; 45 virtual void UniqueInconsistencyDetected( 46 HistogramBase::Inconsistency problem) OVERRIDE; 47 virtual void InconsistencyDetectedInLoggedCount(int amount) OVERRIDE; 48 49 // Calculates deltas in histogram counters. 50 HistogramSnapshotManager histogram_snapshot_manager_; 51 52 // Output buffer for serialized deltas. 53 std::vector<std::string>* serialized_deltas_; 54 55 // Histograms to count inconsistencies in snapshots. 56 HistogramBase* inconsistencies_histogram_; 57 HistogramBase* inconsistencies_unique_histogram_; 58 HistogramBase* inconsistent_snapshot_histogram_; 59 60 DISALLOW_COPY_AND_ASSIGN(HistogramDeltaSerialization); 61 }; 62 63 } // namespace base 64 65 #endif // BASE_METRICS_HISTOGRAM_DELTA_SERIALIZATION_H_ 66
