90 lines
2.3 KiB
C++
90 lines
2.3 KiB
C++
/*
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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#include <functional>
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#include <react/debug/react_native_assert.h>
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namespace facebook {
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namespace react {
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/*
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* Implements a moveable-only function that asserts if called more than once
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* or destroyed before calling.
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* Useful for use in debug mode to ensure such guarantees.
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*/
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template <typename ReturnT = void, typename... ArgumentT>
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class CalledOnceMovableOnlyFunction {
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using T = ReturnT(ArgumentT...);
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std::function<T> function_;
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bool wasCalled_;
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bool wasMovedFrom_;
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public:
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explicit CalledOnceMovableOnlyFunction(std::function<T> &&function)
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: function_(std::move(function)) {
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wasCalled_ = false;
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wasMovedFrom_ = false;
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}
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~CalledOnceMovableOnlyFunction() {
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react_native_assert(
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(wasCalled_ || wasMovedFrom_) &&
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"`CalledOnceMovableOnlyFunction` is destroyed before being called.");
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}
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/*
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* Not copyable.
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*/
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CalledOnceMovableOnlyFunction(CalledOnceMovableOnlyFunction const &other) =
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delete;
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CalledOnceMovableOnlyFunction &operator=(
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CalledOnceMovableOnlyFunction const &other) = delete;
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/*
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* Movable.
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*/
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CalledOnceMovableOnlyFunction(
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CalledOnceMovableOnlyFunction &&other) noexcept {
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wasCalled_ = false;
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wasMovedFrom_ = false;
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other.wasMovedFrom_ = true;
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function_ = std::move(other.function_);
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};
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CalledOnceMovableOnlyFunction &operator=(
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CalledOnceMovableOnlyFunction &&other) noexcept {
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react_native_assert(
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(wasCalled_ || wasMovedFrom_) &&
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"`CalledOnceMovableOnlyFunction` is re-assigned before being called.");
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wasCalled_ = false;
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wasMovedFrom_ = false;
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other.wasMovedFrom_ = true;
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function_ = std::move(other.function_);
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return *this;
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}
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/*
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* Callable.
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*/
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ReturnT operator()(ArgumentT... args) {
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react_native_assert(
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!wasMovedFrom_ &&
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"`CalledOnceMovableOnlyFunction` is called after being moved from.");
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react_native_assert(
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!wasCalled_ &&
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"`CalledOnceMovableOnlyFunction` is called more than once.");
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wasCalled_ = true;
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return function_(args...);
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}
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};
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} // namespace react
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} // namespace facebook
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