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- // Copyright 2022 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 BASE_METRICS_RANGES_MANAGER_H_
- #define BASE_METRICS_RANGES_MANAGER_H_
- #include <unordered_set>
- #include "base/base_export.h"
- #include "base/metrics/bucket_ranges.h"
- namespace base {
- // Manages BucketRanges and their lifetime. When registering a BucketRanges
- // to a RangesManager instance, if an equivalent one already exists (one with
- // the exact same ranges), the passed BucketRanges is deleted. This is useful to
- // prevent duplicate instances of equivalent BucketRanges. Upon the destruction
- // of a RangesManager instance, all BucketRanges managed by it are destroyed. A
- // BucketRanges instance should not be registered to multiple RangesManagers.
- class BASE_EXPORT RangesManager {
- public:
- RangesManager();
- RangesManager(const RangesManager&) = delete;
- RangesManager& operator=(const RangesManager&) = delete;
- ~RangesManager();
- // Registers a BucketRanges. If an equivalent BucketRanges is already
- // registered, then the argument |ranges| will be deleted. The returned value
- // is always the registered BucketRanges (either the argument, or the
- // pre-existing one). Registering a BucketRanges passes the ownership, and
- // will be released when the RangesManager is released.
- const BucketRanges* RegisterOrDeleteDuplicateRanges(
- const BucketRanges* ranges);
- // Gets all registered BucketRanges. The order of returned BucketRanges is not
- // guaranteed.
- std::vector<const BucketRanges*> GetBucketRanges();
- // Some tests may instantiate temporary StatisticsRecorders, each having their
- // own RangesManager. During the tests, ranges may get registered with a
- // recorder that later gets released, which would release the ranges as well.
- // Calling this method prevents this, as the tests may not expect them to be
- // deleted.
- void DoNotReleaseRangesOnDestroyForTesting();
- private:
- // Removes all registered BucketRanges and destroys them. This is called in
- // the destructor.
- void ReleaseBucketRanges();
- // Used to get the hash of a BucketRanges, which is simply its checksum.
- struct BucketRangesHash {
- size_t operator()(const BucketRanges* a) const;
- };
- // Comparator for BucketRanges. See `BucketRanges::Equals()`.
- struct BucketRangesEqual {
- bool operator()(const BucketRanges* a, const BucketRanges* b) const;
- };
- // Type for a set of unique RangesBucket, with their hash and equivalence
- // defined by `BucketRangesHash` and `BucketRangesEqual`.
- typedef std::
- unordered_set<const BucketRanges*, BucketRangesHash, BucketRangesEqual>
- RangesMap;
- // The set of unique BucketRanges registered to the RangesManager.
- RangesMap ranges_;
- // Whether or not to release the registered BucketRanges when this
- // RangesManager is destroyed. See `DoNotReleaseRangesOnDestroyForTesting()`.
- bool do_not_release_ranges_on_destroy_for_testing_ = false;
- };
- } // namespace base
- #endif // BASE_METRICS_RANGES_MANAGER_H_
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