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