1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 // StatisticsRecorder holds all Histograms and BucketRanges that are used by 6 // Histograms in the system. It provides a general place for 7 // Histograms/BucketRanges to register, and supports a global API for accessing 8 // (i.e., dumping, or graphing) the data. 9 10 #ifndef BASE_METRICS_STATISTICS_RECORDER_H_ 11 #define BASE_METRICS_STATISTICS_RECORDER_H_ 12 13 #include <list> 14 #include <map> 15 #include <string> 16 #include <vector> 17 18 #include "base/base_export.h" 19 #include "base/basictypes.h" 20 #include "base/gtest_prod_util.h" 21 #include "base/lazy_instance.h" 22 23 namespace base { 24 25 class BucketRanges; 26 class HistogramBase; 27 class Lock; 28 29 class BASE_EXPORT StatisticsRecorder { 30 public: 31 typedef std::vector<HistogramBase*> Histograms; 32 33 // Initializes the StatisticsRecorder system. Safe to call multiple times. 34 static void Initialize(); 35 36 // Find out if histograms can now be registered into our list. 37 static bool IsActive(); 38 39 // Register, or add a new histogram to the collection of statistics. If an 40 // identically named histogram is already registered, then the argument 41 // |histogram| will deleted. The returned value is always the registered 42 // histogram (either the argument, or the pre-existing registered histogram). 43 static HistogramBase* RegisterOrDeleteDuplicate(HistogramBase* histogram); 44 45 // Register, or add a new BucketRanges. If an identically BucketRanges is 46 // already registered, then the argument |ranges| will deleted. The returned 47 // value is always the registered BucketRanges (either the argument, or the 48 // pre-existing one). 49 static const BucketRanges* RegisterOrDeleteDuplicateRanges( 50 const BucketRanges* ranges); 51 52 // Methods for appending histogram data to a string. Only histograms which 53 // have |query| as a substring are written to |output| (an empty string will 54 // process all registered histograms). 55 static void WriteHTMLGraph(const std::string& query, std::string* output); 56 static void WriteGraph(const std::string& query, std::string* output); 57 58 // Returns the histograms with |query| as a substring as JSON text (an empty 59 // |query| will process all registered histograms). 60 static std::string ToJSON(const std::string& query); 61 62 // Method for extracting histograms which were marked for use by UMA. 63 static void GetHistograms(Histograms* output); 64 65 // Method for extracting BucketRanges used by all histograms registered. 66 static void GetBucketRanges(std::vector<const BucketRanges*>* output); 67 68 // Find a histogram by name. It matches the exact name. This method is thread 69 // safe. It returns NULL if a matching histogram is not found. 70 static HistogramBase* FindHistogram(const std::string& name); 71 72 // GetSnapshot copies some of the pointers to registered histograms into the 73 // caller supplied vector (Histograms). Only histograms which have |query| as 74 // a substring are copied (an empty string will process all registered 75 // histograms). 76 static void GetSnapshot(const std::string& query, Histograms* snapshot); 77 78 private: 79 // We keep all registered histograms in a map, from name to histogram. 80 typedef std::map<std::string, HistogramBase*> HistogramMap; 81 82 // We keep all |bucket_ranges_| in a map, from checksum to a list of 83 // |bucket_ranges_|. Checksum is calculated from the |ranges_| in 84 // |bucket_ranges_|. 85 typedef std::map<uint32, std::list<const BucketRanges*>*> RangesMap; 86 87 friend struct DefaultLazyInstanceTraits<StatisticsRecorder>; 88 friend class HistogramBaseTest; 89 friend class HistogramSnapshotManagerTest; 90 friend class HistogramTest; 91 friend class SparseHistogramTest; 92 friend class StatisticsRecorderTest; 93 FRIEND_TEST_ALL_PREFIXES(HistogramDeltaSerializationTest, 94 DeserializeHistogramAndAddSamples); 95 96 // The constructor just initializes static members. Usually client code should 97 // use Initialize to do this. But in test code, you can friend this class and 98 // call destructor/constructor to get a clean StatisticsRecorder. 99 StatisticsRecorder(); 100 ~StatisticsRecorder(); 101 102 static void DumpHistogramsToVlog(void* instance); 103 104 static HistogramMap* histograms_; 105 static RangesMap* ranges_; 106 107 // Lock protects access to above maps. 108 static base::Lock* lock_; 109 110 DISALLOW_COPY_AND_ASSIGN(StatisticsRecorder); 111 }; 112 113 } // namespace base 114 115 #endif // BASE_METRICS_STATISTICS_RECORDER_H_ 116