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// Copyright 2015 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.
#ifndef COMPONENTS_METRICS_LEAK_DETECTOR_LEAK_ANALYZER_H_
#define COMPONENTS_METRICS_LEAK_DETECTOR_LEAK_ANALYZER_H_
#include <stdint.h>
#include <map>
#include <vector>
#include "base/macros.h"
#include "components/metrics/leak_detector/custom_allocator.h"
#include "components/metrics/leak_detector/leak_detector_value_type.h"
#include "components/metrics/leak_detector/ranked_set.h"
#include "components/metrics/leak_detector/stl_allocator.h"
namespace metrics {
namespace leak_detector {
// This class looks for possible leak patterns in allocation data over time.
// Not thread-safe.
class LeakAnalyzer {
public:
using ValueType = LeakDetectorValueType;
// This class uses CustomAllocator to avoid recursive malloc hook invocation
// when analyzing allocs and frees.
template <typename Type>
using Allocator = STLAllocator<Type, CustomAllocator>;
LeakAnalyzer(uint32_t ranking_size, uint32_t num_suspicions_threshold);
~LeakAnalyzer();
// Take in a RankedSet of allocations, sorted by count. Removes the contents
// of |ranked_entries| to be stored internally, which is why it is not passed
// in as a const reference.
void AddSample(RankedSet ranked_entries);
// Used to report suspected leaks. Reported leaks are sorted by ValueType.
const std::vector<ValueType, Allocator<ValueType>>& suspected_leaks() const {
return suspected_leaks_;
}
private:
// Analyze a list of allocation count deltas from the previous iteration. If
// anything looks like a possible leak, update the suspicion scores.
void AnalyzeDeltas(const RankedSet& ranked_deltas);
// Returns the count for the given value from the previous analysis in
// |count|. Returns true if the given value was present in the previous
// analysis, or false if not.
bool GetPreviousCountForValue(const ValueType& value, uint32_t* count) const;
// Look for the top |ranking_size_| entries when analyzing leaks.
const uint32_t ranking_size_;
// Report suspected leaks when the suspicion score reaches this value.
const uint32_t score_threshold_;
// A mapping of allocation values to suspicion score. All allocations in this
// container are suspected leaks. The score can increase or decrease over
// time. Once the score reaches |score_threshold_|, the entry is reported as
// a suspected leak in |suspected_leaks_|.
std::map<ValueType,
uint32_t,
std::less<ValueType>,
Allocator<std::pair<const ValueType, uint32_t>>>
suspected_histogram_;
// Array of allocated values that passed the suspicion threshold and are being
// reported.
std::vector<ValueType, Allocator<ValueType>> suspected_leaks_;
// The most recent allocation entries, since the last call to AddSample().
RankedSet ranked_entries_;
// The previous allocation entries, from before the last call to AddSample().
RankedSet prev_ranked_entries_;
DISALLOW_COPY_AND_ASSIGN(LeakAnalyzer);
};
} // namespace leak_detector
} // namespace metrics
#endif // COMPONENTS_METRICS_LEAK_DETECTOR_LEAK_ANALYZER_H_
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