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// Copyright 2020 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 MEDIA_BASE_TUNEABLE_H_
#define MEDIA_BASE_TUNEABLE_H_
#include "base/macros.h"
#include "base/time/time.h"
#include "base/unguessable_token.h"
#include "media/base/media_export.h"
namespace media {
// One tuneable value. Each Tuneable has:
// name - Used to set the finch parameter name.
// value - Current runtime value. All Tuneable instances with the same name
// will return the same value. This value will be a constant over the
// lifetime of the process as well.
// min / default / max values - hardcoded range and default for this tuneable.
//
// Via finch, one may enable randomization of the Tuneables, such that a value
// will be chosen at random between a finch-provided miniumum and maximum. This
// minumum and maximum will be constrained by the hardcoded one provided during
// construction. Different Tuneable instances for the same name are still
// guaranteed to be equal, as described above.
template <typename T>
class MEDIA_EXPORT Tuneable {
public:
Tuneable(const char* name, T minimum_value, T default_value, T maximum_value);
Tuneable(const Tuneable&) = delete;
Tuneable(Tuneable&&) = delete;
~Tuneable();
Tuneable& operator=(const Tuneable&) = delete;
Tuneable& operator=(Tuneable&&) = delete;
T value() const { return t_; }
void set_for_testing(T value) { t_ = value; }
private:
T t_;
};
// Set the random number seed that the tuneable will use to choose its value.
// Must be called before the first tuneable is constructed.
void MEDIA_EXPORT SetRandomSeedForTuneables(const base::UnguessableToken& seed);
} // namespace media
#endif // MEDIA_BASE_TUNEABLE_H_
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