48 lines
1.3 KiB
C
48 lines
1.3 KiB
C
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/* Copyright 2022 The OpenXLA Authors.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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==============================================================================*/
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#ifndef XLA_LAZY_H_
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#define XLA_LAZY_H_
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#include <variant>
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#include "absl/functional/any_invocable.h"
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namespace xla {
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template <typename T>
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class Lazy {
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public:
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explicit Lazy(absl::AnyInvocable<T() &&> func)
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: maybe_value_(std::move(func)) {}
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bool has_value() const { return std::holds_alternative<T>(maybe_value_); }
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const T& get() const {
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if (!std::holds_alternative<T>(maybe_value_)) {
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maybe_value_ =
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std::move(std::get<absl::AnyInvocable<T() &&>>(maybe_value_))();
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}
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return std::get<T>(maybe_value_);
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}
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private:
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mutable std::variant<absl::AnyInvocable<T() &&>, T> maybe_value_;
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};
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} // namespace xla
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#endif // XLA_LAZY_H_
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