Repo created

TMessagesProj/jni/voip/webrtc/base/metrics/histogram_delta_serialization.cc

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+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/metrics/histogram_delta_serialization.h"
+
+#include "base/logging.h"
+#include "base/metrics/histogram_base.h"
+#include "base/metrics/histogram_snapshot_manager.h"
+#include "base/metrics/statistics_recorder.h"
+#include "base/numerics/safe_conversions.h"
+#include "base/pickle.h"
+#include "base/values.h"
+
+namespace base {
+
+namespace {
+
+// Create or find existing histogram and add the samples from pickle.
+// Silently returns when seeing any data problem in the pickle.
+void DeserializeHistogramAndAddSamples(PickleIterator* iter) {
+  HistogramBase* histogram = DeserializeHistogramInfo(iter);
+  if (!histogram)
+    return;
+
+  if (histogram->flags() & HistogramBase::kIPCSerializationSourceFlag) {
+    DVLOG(1) << "Single process mode, histogram observed and not copied: "
+             << histogram->histogram_name();
+    return;
+  }
+  histogram->AddSamplesFromPickle(iter);
+}
+
+}  // namespace
+
+HistogramDeltaSerialization::HistogramDeltaSerialization(
+    const std::string& caller_name)
+    : histogram_snapshot_manager_(this), serialized_deltas_(nullptr) {}
+
+HistogramDeltaSerialization::~HistogramDeltaSerialization() = default;
+
+void HistogramDeltaSerialization::PrepareAndSerializeDeltas(
+    std::vector<std::string>* serialized_deltas,
+    bool include_persistent) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  serialized_deltas_ = serialized_deltas;
+  // Note: Before serializing, we set the kIPCSerializationSourceFlag for all
+  // the histograms, so that the receiving process can distinguish them from the
+  // local histograms.
+  StatisticsRecorder::PrepareDeltas(
+      include_persistent, Histogram::kIPCSerializationSourceFlag,
+      Histogram::kNoFlags, &histogram_snapshot_manager_);
+  serialized_deltas_ = nullptr;
+}
+
+// static
+void HistogramDeltaSerialization::DeserializeAndAddSamples(
+    const std::vector<std::string>& serialized_deltas) {
+  for (auto it = serialized_deltas.begin(); it != serialized_deltas.end();
+       ++it) {
+    Pickle pickle(it->data(), checked_cast<int>(it->size()));
+    PickleIterator iter(pickle);
+    DeserializeHistogramAndAddSamples(&iter);
+  }
+}
+
+void HistogramDeltaSerialization::RecordDelta(
+    const HistogramBase& histogram,
+    const HistogramSamples& snapshot) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK_NE(0, snapshot.TotalCount());
+
+  Pickle pickle;
+  histogram.SerializeInfo(&pickle);
+  snapshot.Serialize(&pickle);
+  serialized_deltas_->push_back(
+      std::string(static_cast<const char*>(pickle.data()), pickle.size()));
+}
+
+}  // namespace base