Repo created

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

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+// 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.
+
+#ifndef BASE_METRICS_SPARSE_HISTOGRAM_H_
+#define BASE_METRICS_SPARSE_HISTOGRAM_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <map>
+#include <memory>
+#include <string>
+
+#include "base/base_export.h"
+#include "base/macros.h"
+#include "base/metrics/histogram_base.h"
+#include "base/metrics/histogram_samples.h"
+#include "base/synchronization/lock.h"
+
+namespace base {
+
+class HistogramSamples;
+class PersistentHistogramAllocator;
+class Pickle;
+class PickleIterator;
+
+class BASE_EXPORT SparseHistogram : public HistogramBase {
+ public:
+  // If there's one with same name, return the existing one. If not, create a
+  // new one.
+  static HistogramBase* FactoryGet(const std::string& name, int32_t flags);
+
+  // Create a histogram using data in persistent storage. The allocator must
+  // live longer than the created sparse histogram.
+  static std::unique_ptr<HistogramBase> PersistentCreate(
+      PersistentHistogramAllocator* allocator,
+      const char* name,
+      HistogramSamples::Metadata* meta,
+      HistogramSamples::Metadata* logged_meta);
+
+  ~SparseHistogram() override;
+
+  // HistogramBase implementation:
+  uint64_t name_hash() const override;
+  HistogramType GetHistogramType() const override;
+  bool HasConstructionArguments(Sample expected_minimum,
+                                Sample expected_maximum,
+                                uint32_t expected_bucket_count) const override;
+  void Add(Sample value) override;
+  void AddCount(Sample value, int count) override;
+  void AddSamples(const HistogramSamples& samples) override;
+  bool AddSamplesFromPickle(base::PickleIterator* iter) override;
+  std::unique_ptr<HistogramSamples> SnapshotSamples() const override;
+  std::unique_ptr<HistogramSamples> SnapshotDelta() override;
+  std::unique_ptr<HistogramSamples> SnapshotFinalDelta() const override;
+  void WriteHTMLGraph(std::string* output) const override;
+  void WriteAscii(std::string* output) const override;
+
+ protected:
+  // HistogramBase implementation:
+  void SerializeInfoImpl(base::Pickle* pickle) const override;
+
+ private:
+  // Clients should always use FactoryGet to create SparseHistogram.
+  explicit SparseHistogram(const char* name);
+
+  SparseHistogram(PersistentHistogramAllocator* allocator,
+                  const char* name,
+                  HistogramSamples::Metadata* meta,
+                  HistogramSamples::Metadata* logged_meta);
+
+  friend BASE_EXPORT HistogramBase* DeserializeHistogramInfo(
+      base::PickleIterator* iter);
+  static HistogramBase* DeserializeInfoImpl(base::PickleIterator* iter);
+
+  void GetParameters(DictionaryValue* params) const override;
+  void GetCountAndBucketData(Count* count,
+                             int64_t* sum,
+                             ListValue* buckets) const override;
+
+  // Helpers for emitting Ascii graphic.  Each method appends data to output.
+  void WriteAsciiBody(const HistogramSamples& snapshot,
+                      bool graph_it,
+                      const std::string& newline,
+                      std::string* output) const;
+
+  // Write a common header message describing this histogram.
+  void WriteAsciiHeader(const HistogramSamples& snapshot,
+                        std::string* output) const;
+
+  // For constuctor calling.
+  friend class SparseHistogramTest;
+
+  // Protects access to |samples_|.
+  mutable base::Lock lock_;
+
+  // Flag to indicate if PrepareFinalDelta has been previously called.
+  mutable bool final_delta_created_ = false;
+
+  std::unique_ptr<HistogramSamples> unlogged_samples_;
+  std::unique_ptr<HistogramSamples> logged_samples_;
+
+  DISALLOW_COPY_AND_ASSIGN(SparseHistogram);
+};
+
+}  // namespace base
+
+#endif  // BASE_METRICS_SPARSE_HISTOGRAM_H_