1// Copyright 2013 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#include "base/metrics/histogram_delta_serialization.h"
6
7#include "base/logging.h"
8#include "base/metrics/histogram_base.h"
9#include "base/metrics/histogram_snapshot_manager.h"
10#include "base/metrics/statistics_recorder.h"
11#include "base/numerics/safe_conversions.h"
12#include "base/pickle.h"
13#include "base/values.h"
14
15namespace base {
16
17namespace {
18
19// Create or find existing histogram and add the samples from pickle.
20// Silently returns when seeing any data problem in the pickle.
21void DeserializeHistogramAndAddSamples(PickleIterator* iter) {
22  HistogramBase* histogram = DeserializeHistogramInfo(iter);
23  if (!histogram)
24    return;
25
26  if (histogram->flags() & HistogramBase::kIPCSerializationSourceFlag) {
27    DVLOG(1) << "Single process mode, histogram observed and not copied: "
28             << histogram->histogram_name();
29    return;
30  }
31  histogram->AddSamplesFromPickle(iter);
32}
33
34}  // namespace
35
36HistogramDeltaSerialization::HistogramDeltaSerialization(
37    const std::string& caller_name)
38    : histogram_snapshot_manager_(this),
39      serialized_deltas_(NULL) {
40  inconsistencies_histogram_ =
41      LinearHistogram::FactoryGet(
42          "Histogram.Inconsistencies" + caller_name, 1,
43          HistogramBase::NEVER_EXCEEDED_VALUE,
44          HistogramBase::NEVER_EXCEEDED_VALUE + 1,
45          HistogramBase::kUmaTargetedHistogramFlag);
46
47  inconsistencies_unique_histogram_ =
48      LinearHistogram::FactoryGet(
49          "Histogram.Inconsistencies" + caller_name + "Unique", 1,
50          HistogramBase::NEVER_EXCEEDED_VALUE,
51          HistogramBase::NEVER_EXCEEDED_VALUE + 1,
52          HistogramBase::kUmaTargetedHistogramFlag);
53
54  inconsistent_snapshot_histogram_ =
55      Histogram::FactoryGet(
56          "Histogram.InconsistentSnapshot" + caller_name, 1, 1000000, 50,
57          HistogramBase::kUmaTargetedHistogramFlag);
58}
59
60HistogramDeltaSerialization::~HistogramDeltaSerialization() {
61}
62
63void HistogramDeltaSerialization::PrepareAndSerializeDeltas(
64    std::vector<std::string>* serialized_deltas,
65    bool include_persistent) {
66  DCHECK(thread_checker_.CalledOnValidThread());
67
68  serialized_deltas_ = serialized_deltas;
69  // Note: Before serializing, we set the kIPCSerializationSourceFlag for all
70  // the histograms, so that the receiving process can distinguish them from the
71  // local histograms.
72  histogram_snapshot_manager_.PrepareDeltas(
73      StatisticsRecorder::begin(include_persistent), StatisticsRecorder::end(),
74      Histogram::kIPCSerializationSourceFlag, Histogram::kNoFlags);
75  serialized_deltas_ = NULL;
76}
77
78// static
79void HistogramDeltaSerialization::DeserializeAndAddSamples(
80    const std::vector<std::string>& serialized_deltas) {
81  for (std::vector<std::string>::const_iterator it = serialized_deltas.begin();
82       it != serialized_deltas.end(); ++it) {
83    Pickle pickle(it->data(), checked_cast<int>(it->size()));
84    PickleIterator iter(pickle);
85    DeserializeHistogramAndAddSamples(&iter);
86  }
87}
88
89void HistogramDeltaSerialization::RecordDelta(
90    const HistogramBase& histogram,
91    const HistogramSamples& snapshot) {
92  DCHECK(thread_checker_.CalledOnValidThread());
93  DCHECK_NE(0, snapshot.TotalCount());
94
95  Pickle pickle;
96  histogram.SerializeInfo(&pickle);
97  snapshot.Serialize(&pickle);
98  serialized_deltas_->push_back(
99      std::string(static_cast<const char*>(pickle.data()), pickle.size()));
100}
101
102void HistogramDeltaSerialization::InconsistencyDetected(
103    HistogramBase::Inconsistency problem) {
104  DCHECK(thread_checker_.CalledOnValidThread());
105
106  inconsistencies_histogram_->Add(problem);
107}
108
109void HistogramDeltaSerialization::UniqueInconsistencyDetected(
110    HistogramBase::Inconsistency problem) {
111  DCHECK(thread_checker_.CalledOnValidThread());
112
113  inconsistencies_unique_histogram_->Add(problem);
114}
115
116void HistogramDeltaSerialization::InconsistencyDetectedInLoggedCount(
117    int amount) {
118  DCHECK(thread_checker_.CalledOnValidThread());
119
120  inconsistent_snapshot_histogram_->Add(std::abs(amount));
121}
122
123}  // namespace base
124