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/macros.h" 13 #include "base/memory/scoped_ptr.h" 14 #include "base/metrics/histogram_flattener.h" 15 #include "base/metrics/histogram_snapshot_manager.h" 16 #include "base/threading/thread_checker.h" 17 18 namespace base { 19 20 class HistogramBase; 21 22 // Serializes and restores histograms deltas. 23 class BASE_EXPORT HistogramDeltaSerialization : public HistogramFlattener { 24 public: 25 // |caller_name| is string used in histograms for counting inconsistencies. 26 explicit HistogramDeltaSerialization(const std::string& caller_name); 27 ~HistogramDeltaSerialization() override; 28 29 // Computes deltas in histogram bucket counts relative to the previous call to 30 // this method. Stores the deltas in serialized form into |serialized_deltas|. 31 // If |serialized_deltas| is NULL, no data is serialized, though the next call 32 // will compute the deltas relative to this one. 33 void PrepareAndSerializeDeltas(std::vector<std::string>* serialized_deltas); 34 35 // Deserialize deltas and add samples to corresponding histograms, creating 36 // them if necessary. Silently ignores errors in |serialized_deltas|. 37 static void DeserializeAndAddSamples( 38 const std::vector<std::string>& serialized_deltas); 39 40 private: 41 // HistogramFlattener implementation. 42 void RecordDelta(const HistogramBase& histogram, 43 const HistogramSamples& snapshot) override; 44 void InconsistencyDetected(HistogramBase::Inconsistency problem) override; 45 void UniqueInconsistencyDetected( 46 HistogramBase::Inconsistency problem) override; 47 void InconsistencyDetectedInLoggedCount(int amount) override; 48 49 ThreadChecker thread_checker_; 50 51 // Calculates deltas in histogram counters. 52 HistogramSnapshotManager histogram_snapshot_manager_; 53 54 // Output buffer for serialized deltas. 55 std::vector<std::string>* serialized_deltas_; 56 57 // Histograms to count inconsistencies in snapshots. 58 HistogramBase* inconsistencies_histogram_; 59 HistogramBase* inconsistencies_unique_histogram_; 60 HistogramBase* inconsistent_snapshot_histogram_; 61 62 DISALLOW_COPY_AND_ASSIGN(HistogramDeltaSerialization); 63 }; 64 65 } // namespace base 66 67 #endif // BASE_METRICS_HISTOGRAM_DELTA_SERIALIZATION_H_ 68
