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// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "components/metrics/library_support/histogram_manager.h"
#include <string>
#include <vector>
#include "base/lazy_instance.h"
#include "base/metrics/histogram_macros.h"
#include "base/metrics/histogram_samples.h"
#include "base/metrics/statistics_recorder.h"
#include "base/thread_annotations.h"
#include "components/metrics/histogram_encoder.h"
namespace metrics {
// TODO(rtenneti): move g_histogram_manager into java code.
static base::LazyInstance<HistogramManager>::Leaky g_histogram_manager =
LAZY_INSTANCE_INITIALIZER;
HistogramManager::HistogramManager() : histogram_snapshot_manager_(this) {}
HistogramManager::~HistogramManager() = default;
// static
HistogramManager* HistogramManager::GetInstance() {
return g_histogram_manager.Pointer();
}
void HistogramManager::RecordDelta(const base::HistogramBase& histogram,
const base::HistogramSamples& snapshot) {
EncodeHistogramDelta(histogram.histogram_name(), snapshot, &uma_proto_);
}
// TODO(lukasza): https://crbug.com/881903: NO_THREAD_SAFETY_ANALYSIS below can
// be removed once base::Lock::Try is annotated with EXCLUSIVE_TRYLOCK_FUNCTION.
bool HistogramManager::GetDeltas(std::vector<uint8_t>* data)
NO_THREAD_SAFETY_ANALYSIS {
if (get_deltas_lock_.Try()) {
base::AutoLock lock(get_deltas_lock_, base::AutoLock::AlreadyAcquired());
// Clear the protobuf between calls.
uma_proto_.Clear();
// "false" indicates to *not* include histograms held in persistent storage
// on the assumption that they will be visible to the recipient through
// other means.
base::StatisticsRecorder::PrepareDeltas(
false, base::Histogram::kNoFlags,
base::Histogram::kUmaTargetedHistogramFlag,
&histogram_snapshot_manager_);
int32_t data_size = uma_proto_.ByteSizeLong();
data->resize(data_size);
if (data_size == 0 || uma_proto_.SerializeToArray(data->data(), data_size))
return true;
}
data->clear();
return false;
}
} // namespace metrics
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