Commit 76c92e2
| Original file line number | Diff line number | Diff line change | |
|---|---|---|---|
@@ -463,6 +463,13 @@ constexpr auto as( std::optional<T> const& x ) -> auto&& | |||
| 463 | 463 | using cpp2::cpp2_new; | |
| 464 | 464 | ||
| 465 | 465 | ||
| 466 | + //----------------------------------------------------------------------- | ||
| 467 | + // | ||
| 468 | + // A partial implementation of GSL features Cpp2 relies on, | ||
| 469 | + // to keep this a standalone header without non-std dependencies | ||
| 470 | + // | ||
| 471 | + //----------------------------------------------------------------------- | ||
| 472 | + // | ||
| 466 | 473 | namespace gsl { | |
| 467 | 474 | ||
| 468 | 475 | //----------------------------------------------------------------------- | |
@@ -477,6 +484,46 @@ constexpr auto narrow_cast(From&& from) noexcept -> To | |||
| 477 | 484 | return static_cast<To>(std::forward<From>(from)); | |
| 478 | 485 | } | |
| 479 | 486 | ||
| 487 | + | ||
| 488 | + //----------------------------------------------------------------------- | ||
| 489 | + // | ||
| 490 | + // An implementation of GSL's final_action and finally | ||
| 491 | + // (based on a PR I contributed to Microsoft GSL) | ||
| 492 | + // | ||
| 493 | + // final_action ensures something is run at the end of a scope | ||
| 494 | + // | ||
| 495 | + // finally is a convenience function to generate a final_action | ||
| 496 | + // | ||
| 497 | + //----------------------------------------------------------------------- | ||
| 498 | + // | ||
| 499 | + template <class F> | ||
| 500 | + class final_action | ||
| 501 | + { | ||
| 502 | + public: | ||
| 503 | + template <class FF> | ||
| 504 | + explicit final_action(FF&& ff) noexcept : f{std::forward<FF>(ff)} { } | ||
| 505 | + | ||
| 506 | + ~final_action() noexcept { if (invoke) f(); } | ||
| 507 | + | ||
| 508 | + final_action(final_action&& other) noexcept | ||
| 509 | + : f(std::move(other.f)), invoke(std::exchange(other.invoke, false)) | ||
| 510 | + { } | ||
| 511 | + | ||
| 512 | + final_action(const final_action& rhs) = delete; | ||
| 513 | + void operator=(const final_action&) = delete; | ||
| 514 | + void operator=(final_action&& other) = delete; | ||
| 515 | + | ||
| 516 | + private: | ||
| 517 | + F f; | ||
| 518 | + bool invoke = true; | ||
| 519 | + }; | ||
| 520 | + | ||
| 521 | + template <class F> | ||
| 522 | + [[nodiscard]] auto finally(F&& f) noexcept | ||
| 523 | + { | ||
| 524 | + return final_action<F>{std::forward<F>(f)}; | ||
| 525 | + } | ||
| 526 | + | ||
| 480 | 527 | } | |
| 481 | 528 | ||
| 482 | 529 | #endif | |
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