Repo created

TMessagesProj/jni/voip/webrtc/base/metrics/histogram_delta_serialization.h

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+// Copyright 2013 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.
+
+#ifndef BASE_METRICS_HISTOGRAM_DELTA_SERIALIZATION_H_
+#define BASE_METRICS_HISTOGRAM_DELTA_SERIALIZATION_H_
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "base/base_export.h"
+#include "base/macros.h"
+#include "base/metrics/histogram_flattener.h"
+#include "base/metrics/histogram_snapshot_manager.h"
+#include "base/threading/thread_checker.h"
+
+namespace base {
+
+class HistogramBase;
+
+// Serializes and restores histograms deltas.
+class BASE_EXPORT HistogramDeltaSerialization : public HistogramFlattener {
+ public:
+  // |caller_name| is string used in histograms for counting inconsistencies.
+  explicit HistogramDeltaSerialization(const std::string& caller_name);
+  ~HistogramDeltaSerialization() override;
+
+  // Computes deltas in histogram bucket counts relative to the previous call to
+  // this method. Stores the deltas in serialized form into |serialized_deltas|.
+  // If |serialized_deltas| is null, no data is serialized, though the next call
+  // will compute the deltas relative to this one. Setting |include_persistent|
+  // will include histograms held in persistent memory (and thus may be reported
+  // elsewhere); otherwise only histograms local to this process are serialized.
+  void PrepareAndSerializeDeltas(std::vector<std::string>* serialized_deltas,
+                                 bool include_persistent);
+
+  // Deserialize deltas and add samples to corresponding histograms, creating
+  // them if necessary. Silently ignores errors in |serialized_deltas|.
+  static void DeserializeAndAddSamples(
+      const std::vector<std::string>& serialized_deltas);
+
+ private:
+  // HistogramFlattener implementation.
+  void RecordDelta(const HistogramBase& histogram,
+                   const HistogramSamples& snapshot) override;
+
+  ThreadChecker thread_checker_;
+
+  // Calculates deltas in histogram counters.
+  HistogramSnapshotManager histogram_snapshot_manager_;
+
+  // Output buffer for serialized deltas.
+  std::vector<std::string>* serialized_deltas_;
+
+  DISALLOW_COPY_AND_ASSIGN(HistogramDeltaSerialization);
+};
+
+}  // namespace base
+
+#endif  // BASE_METRICS_HISTOGRAM_DELTA_SERIALIZATION_H_