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// Copyright (C) 2018 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <ostream>
namespace iorap {
// kIsDebugBuild is special.
// It gets to be in the 'iorap' namespace
// so that different modules don't need to qualify it.
#ifndef NDEBUG
static constexpr bool kIsDebugBuild = true;
#else
static constexpr bool kIsDebugBuild = false;
#endif
namespace common {
// TODO: move below code to helpers.
template <typename T, bool>
struct base_if_condition {};
template <typename T>
struct base_if_condition<T, true> : public T {};
template <typename T>
using base_if_debug = base_if_condition<T, kIsDebugBuild>;
namespace detail {
// "if constexpr" doesn't allow us to exclude fields from a struct/class,
// and also "if constexpr" doesn't allow us to reference a field that does not
// exist.
// so we must move everything into a separate base class.
template <bool kIsDebug = kIsDebugBuild>
struct DebugCounterBase {
constexpr size_t value() const {
return counter;
}
constexpr void set_value(size_t value) {
counter = value;
}
size_t counter{1}; // Don't start with 0.
};
template <>
struct DebugCounterBase<false /*kIsDebug*/> {
constexpr size_t value() const {
return 0;
}
constexpr void set_value(size_t value) {
}
};
} // namespace detail
// This counter does absolutely nothing, the code compiles to no-ops
// when debugging is disabled.
struct DebugCounter : detail::DebugCounterBase<> {
constexpr DebugCounter& operator++() {
set_value(value() + 1);
return *this;
}
constexpr DebugCounter operator++(int) {
DebugCounter now = *this;
set_value(value() + 1);
return now;
}
constexpr operator size_t() const {
return value();
}
friend std::ostream& operator<<(std::ostream& os, DebugCounter counter);
};
inline std::ostream& operator<<(std::ostream& os, DebugCounter counter) {
os << counter.value();
return os;
}
// TODO: refactor DebugCounter and base traits into their own files?
} // namespace common
} // namespace iorap
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