| // 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. |
| |
| // StatisticsRecorder holds all Histograms and BucketRanges that are used by |
| // Histograms in the system. It provides a general place for |
| // Histograms/BucketRanges to register, and supports a global API for accessing |
| // (i.e., dumping, or graphing) the data. |
| |
| #ifndef BASE_METRICS_STATISTICS_RECORDER_H_ |
| #define BASE_METRICS_STATISTICS_RECORDER_H_ |
| |
| #include <list> |
| #include <map> |
| #include <string> |
| #include <vector> |
| |
| #include "base/base_export.h" |
| #include "base/basictypes.h" |
| #include "base/callback.h" |
| #include "base/gtest_prod_util.h" |
| #include "base/lazy_instance.h" |
| #include "base/metrics/histogram_base.h" |
| |
| namespace base { |
| |
| class BucketRanges; |
| class Lock; |
| |
| class BASE_EXPORT StatisticsRecorder { |
| public: |
| typedef std::vector<HistogramBase*> Histograms; |
| |
| // Initializes the StatisticsRecorder system. Safe to call multiple times. |
| static void Initialize(); |
| |
| // Find out if histograms can now be registered into our list. |
| static bool IsActive(); |
| |
| // Register, or add a new histogram to the collection of statistics. If an |
| // identically named histogram is already registered, then the argument |
| // |histogram| will deleted. The returned value is always the registered |
| // histogram (either the argument, or the pre-existing registered histogram). |
| static HistogramBase* RegisterOrDeleteDuplicate(HistogramBase* histogram); |
| |
| // Register, or add a new BucketRanges. If an identically BucketRanges is |
| // already registered, then the argument |ranges| will deleted. The returned |
| // value is always the registered BucketRanges (either the argument, or the |
| // pre-existing one). |
| static const BucketRanges* RegisterOrDeleteDuplicateRanges( |
| const BucketRanges* ranges); |
| |
| // Methods for appending histogram data to a string. Only histograms which |
| // have |query| as a substring are written to |output| (an empty string will |
| // process all registered histograms). |
| static void WriteHTMLGraph(const std::string& query, std::string* output); |
| static void WriteGraph(const std::string& query, std::string* output); |
| |
| // Returns the histograms with |query| as a substring as JSON text (an empty |
| // |query| will process all registered histograms). |
| static std::string ToJSON(const std::string& query); |
| |
| // Method for extracting histograms which were marked for use by UMA. |
| static void GetHistograms(Histograms* output); |
| |
| // Method for extracting BucketRanges used by all histograms registered. |
| static void GetBucketRanges(std::vector<const BucketRanges*>* output); |
| |
| // Find a histogram by name. It matches the exact name. This method is thread |
| // safe. It returns NULL if a matching histogram is not found. |
| static HistogramBase* FindHistogram(const std::string& name); |
| |
| // GetSnapshot copies some of the pointers to registered histograms into the |
| // caller supplied vector (Histograms). Only histograms which have |query| as |
| // a substring are copied (an empty string will process all registered |
| // histograms). |
| static void GetSnapshot(const std::string& query, Histograms* snapshot); |
| |
| typedef base::Callback<void(HistogramBase::Sample)> OnSampleCallback; |
| |
| // SetCallback sets the callback to notify when a new sample is recorded on |
| // the histogram referred to by |histogram_name|. The call to this method can |
| // be be done before or after the histogram is created. This method is thread |
| // safe. The return value is whether or not the callback was successfully set. |
| static bool SetCallback(const std::string& histogram_name, |
| const OnSampleCallback& callback); |
| |
| // ClearCallback clears any callback set on the histogram referred to by |
| // |histogram_name|. This method is thread safe. |
| static void ClearCallback(const std::string& histogram_name); |
| |
| // FindCallback retrieves the callback for the histogram referred to by |
| // |histogram_name|, or a null callback if no callback exists for this |
| // histogram. This method is thread safe. |
| static OnSampleCallback FindCallback(const std::string& histogram_name); |
| |
| private: |
| // HistogramNameRef holds a weak const ref to the name field of the associated |
| // Histogram object, allowing re-use of the underlying string storage for the |
| // map keys. The wrapper is required as using "const std::string&" as the key |
| // results in compile errors. |
| struct HistogramNameRef { |
| explicit HistogramNameRef(const std::string& name) : name_(name) {}; |
| |
| // Operator < is necessary to use this type as a std::map key. |
| bool operator<(const HistogramNameRef& other) const { |
| return name_ < other.name_; |
| } |
| |
| // Weak, owned by the associated Histogram object. |
| const std::string& name_; |
| }; |
| |
| // We keep all registered histograms in a map, from name to histogram. |
| typedef std::map<HistogramNameRef, HistogramBase*> HistogramMap; |
| |
| // We keep a map of callbacks to histograms, so that as histograms are |
| // created, we can set the callback properly. |
| typedef std::map<std::string, OnSampleCallback> CallbackMap; |
| |
| // We keep all |bucket_ranges_| in a map, from checksum to a list of |
| // |bucket_ranges_|. Checksum is calculated from the |ranges_| in |
| // |bucket_ranges_|. |
| typedef std::map<uint32, std::list<const BucketRanges*>*> RangesMap; |
| |
| friend struct DefaultLazyInstanceTraits<StatisticsRecorder>; |
| friend class HistogramBaseTest; |
| friend class HistogramSnapshotManagerTest; |
| friend class HistogramTest; |
| friend class JsonPrefStoreTest; |
| friend class SparseHistogramTest; |
| friend class StatisticsRecorderTest; |
| FRIEND_TEST_ALL_PREFIXES(HistogramDeltaSerializationTest, |
| DeserializeHistogramAndAddSamples); |
| |
| // The constructor just initializes static members. Usually client code should |
| // use Initialize to do this. But in test code, you can friend this class and |
| // call destructor/constructor to get a clean StatisticsRecorder. |
| StatisticsRecorder(); |
| ~StatisticsRecorder(); |
| |
| static void DumpHistogramsToVlog(void* instance); |
| |
| static HistogramMap* histograms_; |
| static CallbackMap* callbacks_; |
| static RangesMap* ranges_; |
| |
| // Lock protects access to above maps. |
| static base::Lock* lock_; |
| |
| DISALLOW_COPY_AND_ASSIGN(StatisticsRecorder); |
| }; |
| |
| } // namespace base |
| |
| #endif // BASE_METRICS_STATISTICS_RECORDER_H_ |