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