// 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 #include #include #include #include #include "base/base_export.h" #include "base/metrics/histogram_base.h" #include "base/metrics/histogram_samples.h" #include "base/synchronization/lock.h" #include "base/values.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 PersistentCreate( PersistentHistogramAllocator* allocator, const char* name, HistogramSamples::Metadata* meta, HistogramSamples::Metadata* logged_meta); SparseHistogram(const SparseHistogram&) = delete; SparseHistogram& operator=(const SparseHistogram&) = delete; ~SparseHistogram() override; // HistogramBase implementation: uint64_t name_hash() const override; HistogramType GetHistogramType() const override; bool HasConstructionArguments(Sample expected_minimum, Sample expected_maximum, size_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 SnapshotSamples() const override; std::unique_ptr SnapshotDelta() override; std::unique_ptr SnapshotFinalDelta() const override; base::Value::Dict ToGraphDict() 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); // Writes the type of the sparse histogram in the |params|. Value::Dict GetParameters() const override; // For constructor 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 unlogged_samples_; std::unique_ptr logged_samples_; }; } // namespace base #endif // BASE_METRICS_SPARSE_HISTOGRAM_H_