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