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| 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/callback.h" | |
| 21 #include "base/gtest_prod_util.h" | |
| 22 #include "base/lazy_instance.h" | |
| 23 #include "base/metrics/histogram_base.h" | |
| 24 | |
| 25 namespace base { | |
| 26 | |
| 27 class BucketRanges; | |
| 28 class Lock; | |
| 29 | |
| 30 class BASE_EXPORT StatisticsRecorder { | |
| 31 public: | |
| 32 typedef std::vector<HistogramBase*> Histograms; | |
| 33 | |
| 34 // Initializes the StatisticsRecorder system. Safe to call multiple times. | |
| 35 static void Initialize(); | |
| 36 | |
| 37 // Find out if histograms can now be registered into our list. | |
| 38 static bool IsActive(); | |
| 39 | |
| 40 // Register, or add a new histogram to the collection of statistics. If an | |
| 41 // identically named histogram is already registered, then the argument | |
| 42 // |histogram| will deleted. The returned value is always the registered | |
| 43 // histogram (either the argument, or the pre-existing registered histogram). | |
| 44 static HistogramBase* RegisterOrDeleteDuplicate(HistogramBase* histogram); | |
| 45 | |
| 46 // Register, or add a new BucketRanges. If an identically BucketRanges is | |
| 47 // already registered, then the argument |ranges| will deleted. The returned | |
| 48 // value is always the registered BucketRanges (either the argument, or the | |
| 49 // pre-existing one). | |
| 50 static const BucketRanges* RegisterOrDeleteDuplicateRanges( | |
| 51 const BucketRanges* ranges); | |
| 52 | |
| 53 // Methods for appending histogram data to a string. Only histograms which | |
| 54 // have |query| as a substring are written to |output| (an empty string will | |
| 55 // process all registered histograms). | |
| 56 static void WriteHTMLGraph(const std::string& query, std::string* output); | |
| 57 static void WriteGraph(const std::string& query, std::string* output); | |
| 58 | |
| 59 // Returns the histograms with |query| as a substring as JSON text (an empty | |
| 60 // |query| will process all registered histograms). | |
| 61 static std::string ToJSON(const std::string& query); | |
| 62 | |
| 63 // Method for extracting histograms which were marked for use by UMA. | |
| 64 static void GetHistograms(Histograms* output); | |
| 65 | |
| 66 // Method for extracting BucketRanges used by all histograms registered. | |
| 67 static void GetBucketRanges(std::vector<const BucketRanges*>* output); | |
| 68 | |
| 69 // Find a histogram by name. It matches the exact name. This method is thread | |
| 70 // safe. It returns NULL if a matching histogram is not found. | |
| 71 static HistogramBase* FindHistogram(const std::string& name); | |
| 72 | |
| 73 // GetSnapshot copies some of the pointers to registered histograms into the | |
| 74 // caller supplied vector (Histograms). Only histograms which have |query| as | |
| 75 // a substring are copied (an empty string will process all registered | |
| 76 // histograms). | |
| 77 static void GetSnapshot(const std::string& query, Histograms* snapshot); | |
| 78 | |
| 79 typedef base::Callback<void(HistogramBase::Sample)> OnSampleCallback; | |
| 80 | |
| 81 // SetCallback sets the callback to notify when a new sample is recorded on | |
| 82 // the histogram referred to by |histogram_name|. The call to this method can | |
| 83 // be be done before or after the histogram is created. This method is thread | |
| 84 // safe. The return value is whether or not the callback was successfully set. | |
| 85 static bool SetCallback(const std::string& histogram_name, | |
| 86 const OnSampleCallback& callback); | |
| 87 | |
| 88 // ClearCallback clears any callback set on the histogram referred to by | |
| 89 // |histogram_name|. This method is thread safe. | |
| 90 static void ClearCallback(const std::string& histogram_name); | |
| 91 | |
| 92 // FindCallback retrieves the callback for the histogram referred to by | |
| 93 // |histogram_name|, or a null callback if no callback exists for this | |
| 94 // histogram. This method is thread safe. | |
| 95 static OnSampleCallback FindCallback(const std::string& histogram_name); | |
| 96 | |
| 97 private: | |
| 98 // HistogramNameRef holds a weak const ref to the name field of the associated | |
| 99 // Histogram object, allowing re-use of the underlying string storage for the | |
| 100 // map keys. The wrapper is required as using "const std::string&" as the key | |
| 101 // results in compile errors. | |
| 102 struct HistogramNameRef { | |
| 103 explicit HistogramNameRef(const std::string& name) : name_(name){}; | |
| 104 | |
| 105 // Operator < is necessary to use this type as a std::map key. | |
| 106 bool operator<(const HistogramNameRef& other) const { | |
| 107 return name_ < other.name_; | |
| 108 } | |
| 109 | |
| 110 // Weak, owned by the associated Histogram object. | |
| 111 const std::string& name_; | |
| 112 }; | |
| 113 | |
| 114 // We keep all registered histograms in a map, from name to histogram. | |
| 115 typedef std::map<HistogramNameRef, HistogramBase*> HistogramMap; | |
| 116 | |
| 117 // We keep a map of callbacks to histograms, so that as histograms are | |
| 118 // created, we can set the callback properly. | |
| 119 typedef std::map<std::string, OnSampleCallback> CallbackMap; | |
| 120 | |
| 121 // We keep all |bucket_ranges_| in a map, from checksum to a list of | |
| 122 // |bucket_ranges_|. Checksum is calculated from the |ranges_| in | |
| 123 // |bucket_ranges_|. | |
| 124 typedef std::map<uint32, std::list<const BucketRanges*>*> RangesMap; | |
| 125 | |
| 126 friend struct DefaultLazyInstanceTraits<StatisticsRecorder>; | |
| 127 friend class HistogramBaseTest; | |
| 128 friend class HistogramSnapshotManagerTest; | |
| 129 friend class HistogramTest; | |
| 130 friend class JsonPrefStoreTest; | |
| 131 friend class SparseHistogramTest; | |
| 132 friend class StatisticsRecorderTest; | |
| 133 FRIEND_TEST_ALL_PREFIXES(HistogramDeltaSerializationTest, | |
| 134 DeserializeHistogramAndAddSamples); | |
| 135 | |
| 136 // The constructor just initializes static members. Usually client code should | |
| 137 // use Initialize to do this. But in test code, you can friend this class and | |
| 138 // call destructor/constructor to get a clean StatisticsRecorder. | |
| 139 StatisticsRecorder(); | |
| 140 ~StatisticsRecorder(); | |
| 141 | |
| 142 static void DumpHistogramsToVlog(void* instance); | |
| 143 | |
| 144 static HistogramMap* histograms_; | |
| 145 static CallbackMap* callbacks_; | |
| 146 static RangesMap* ranges_; | |
| 147 | |
| 148 // Lock protects access to above maps. | |
| 149 static base::Lock* lock_; | |
| 150 | |
| 151 DISALLOW_COPY_AND_ASSIGN(StatisticsRecorder); | |
| 152 }; | |
| 153 | |
| 154 } // namespace base | |
| 155 | |
| 156 #endif // BASE_METRICS_STATISTICS_RECORDER_H_ | |
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