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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 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 | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef BASE_METRICS_HISTOGRAM_SNAPSHOT_MANAGER_H_ | 5 #ifndef BASE_METRICS_HISTOGRAM_SNAPSHOT_MANAGER_H_ |
6 #define BASE_METRICS_HISTOGRAM_SNAPSHOT_MANAGER_H_ | 6 #define BASE_METRICS_HISTOGRAM_SNAPSHOT_MANAGER_H_ |
7 | 7 |
8 #include <stdint.h> | 8 #include <stdint.h> |
9 | 9 |
10 #include <map> | 10 #include <map> |
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33 virtual ~HistogramSnapshotManager(); | 33 virtual ~HistogramSnapshotManager(); |
34 | 34 |
35 // Snapshot all histograms, and ask |histogram_flattener_| to record the | 35 // Snapshot all histograms, and ask |histogram_flattener_| to record the |
36 // delta. |flags_to_set| is used to set flags for each histogram. | 36 // delta. |flags_to_set| is used to set flags for each histogram. |
37 // |required_flags| is used to select histograms to be recorded. | 37 // |required_flags| is used to select histograms to be recorded. |
38 // Only histograms that have all the flags specified by the argument will be | 38 // Only histograms that have all the flags specified by the argument will be |
39 // chosen. If all histograms should be recorded, set it to | 39 // chosen. If all histograms should be recorded, set it to |
40 // |Histogram::kNoFlags|. Though any "forward" iterator will work, the | 40 // |Histogram::kNoFlags|. Though any "forward" iterator will work, the |
41 // histograms over which it iterates *must* remain valid until this method | 41 // histograms over which it iterates *must* remain valid until this method |
42 // returns; the iterator cannot deallocate histograms once it iterates past | 42 // returns; the iterator cannot deallocate histograms once it iterates past |
43 // them. | 43 // them and FinishDeltas() has been called after. StartDeltas() must be |
| 44 // called before. |
| 45 template <class ForwardHistogramIterator> |
| 46 void PrepareDeltasWithoutStartFinish(ForwardHistogramIterator begin, |
| 47 ForwardHistogramIterator end, |
| 48 HistogramBase::Flags flags_to_set, |
| 49 HistogramBase::Flags required_flags) { |
| 50 for (ForwardHistogramIterator it = begin; it != end; ++it) { |
| 51 (*it)->SetFlags(flags_to_set); |
| 52 if (((*it)->flags() & required_flags) == required_flags) |
| 53 PrepareDelta(*it); |
| 54 } |
| 55 } |
| 56 |
| 57 // As above but also calls StartDeltas() and FinishDeltas(). |
44 template <class ForwardHistogramIterator> | 58 template <class ForwardHistogramIterator> |
45 void PrepareDeltas(ForwardHistogramIterator begin, | 59 void PrepareDeltas(ForwardHistogramIterator begin, |
46 ForwardHistogramIterator end, | 60 ForwardHistogramIterator end, |
47 HistogramBase::Flags flags_to_set, | 61 HistogramBase::Flags flags_to_set, |
48 HistogramBase::Flags required_flags) { | 62 HistogramBase::Flags required_flags) { |
49 StartDeltas(); | 63 StartDeltas(); |
50 for (ForwardHistogramIterator it = begin; it != end; ++it) { | 64 PrepareDeltasWithoutStartFinish(begin, end, flags_to_set, required_flags); |
51 (*it)->SetFlags(flags_to_set); | |
52 if (((*it)->flags() & required_flags) == required_flags) | |
53 PrepareDelta(*it); | |
54 } | |
55 FinishDeltas(); | 65 FinishDeltas(); |
56 } | 66 } |
57 | 67 |
58 // When the collection is not so simple as can be done using a single | 68 // When the collection is not so simple as can be done using a single |
59 // iterator, the steps can be performed separately. Call PerpareDelta() | 69 // iterator, the steps can be performed separately. Call PerpareDelta() |
60 // as many times as necessary with a single StartDeltas() before and | 70 // as many times as necessary with a single StartDeltas() before and |
61 // a single FinishDeltas() after. All passed histograms must live | 71 // a single FinishDeltas() after. All passed histograms must live |
62 // until FinishDeltas() completes. PrepareAbsolute() works the same | 72 // until FinishDeltas() completes. PrepareAbsolute() works the same |
63 // but assumes there were no previous logged values and no future deltas | 73 // but assumes there were no previous logged values and no future deltas |
64 // will be created (and thus can work on read-only histograms). | 74 // will be created (and thus can work on read-only histograms). |
| 75 // PrepareFinalDelta() works like PrepareDelta() except that it does |
| 76 // not update the previous logged values and can thus be used with |
| 77 // read-only files. |
65 // Use Prepare*TakingOwnership() if it is desireable to have this class | 78 // Use Prepare*TakingOwnership() if it is desireable to have this class |
66 // automatically delete the histogram once it is "finished". | 79 // automatically delete the histogram once it is "finished". |
67 void StartDeltas(); | 80 void StartDeltas(); |
68 void PrepareDelta(HistogramBase* histogram); | 81 void PrepareDelta(HistogramBase* histogram); |
69 void PrepareDeltaTakingOwnership(std::unique_ptr<HistogramBase> histogram); | 82 void PrepareDeltaTakingOwnership(std::unique_ptr<HistogramBase> histogram); |
70 void PrepareAbsolute(const HistogramBase* histogram); | 83 void PrepareAbsolute(const HistogramBase* histogram); |
71 void PrepareAbsoluteTakingOwnership( | 84 void PrepareAbsoluteTakingOwnership( |
72 std::unique_ptr<const HistogramBase> histogram); | 85 std::unique_ptr<const HistogramBase> histogram); |
| 86 void PrepareFinalDeltaTakingOwnership( |
| 87 std::unique_ptr<const HistogramBase> histogram); |
73 void FinishDeltas(); | 88 void FinishDeltas(); |
74 | 89 |
75 private: | 90 private: |
76 FRIEND_TEST_ALL_PREFIXES(HistogramSnapshotManagerTest, CheckMerge); | 91 FRIEND_TEST_ALL_PREFIXES(HistogramSnapshotManagerTest, CheckMerge); |
77 | 92 |
78 // During a snapshot, samples are acquired and aggregated. This structure | 93 // During a snapshot, samples are acquired and aggregated. This structure |
79 // contains all the information collected for a given histogram. Once a | 94 // contains all the information collected for a given histogram. Once a |
80 // snapshot operation is finished, it is generally emptied except for | 95 // snapshot operation is finished, it is generally emptied except for |
81 // information that must persist from one report to the next, such as | 96 // information that must persist from one report to the next, such as |
82 // the "inconsistencies". | 97 // the "inconsistencies". |
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121 // |histogram_flattener_| handles the logistics of recording the histogram | 136 // |histogram_flattener_| handles the logistics of recording the histogram |
122 // deltas. | 137 // deltas. |
123 HistogramFlattener* histogram_flattener_; // Weak. | 138 HistogramFlattener* histogram_flattener_; // Weak. |
124 | 139 |
125 DISALLOW_COPY_AND_ASSIGN(HistogramSnapshotManager); | 140 DISALLOW_COPY_AND_ASSIGN(HistogramSnapshotManager); |
126 }; | 141 }; |
127 | 142 |
128 } // namespace base | 143 } // namespace base |
129 | 144 |
130 #endif // BASE_METRICS_HISTOGRAM_SNAPSHOT_MANAGER_H_ | 145 #endif // BASE_METRICS_HISTOGRAM_SNAPSHOT_MANAGER_H_ |
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