From 5b65c4af5107176555b23a638e5947686410ac1f Mon Sep 17 00:00:00 2001 From: Abseil Team Date: Wed, 27 Mar 2019 08:05:41 -0700 Subject: Export of internal Abseil changes. -- f6c627ce4470a814adc377947b58346eef69a4c9 by Jon Cohen : Don't create install rules when Abseil is used as a subdirectory. Fix #287 PiperOrigin-RevId: 240559825 -- a5d9b06fe736143068997988b654b5f66ec3266a by Matt Calabrese : Make absl::nullopt an inline constexpr variable, as specified in the standard (with a workaround for pre-c++17 compilers). PiperOrigin-RevId: 240552286 -- d7bee50cff745fbb8d1cdf56a200d9073d311c80 by Abseil Team : Internal Change PiperOrigin-RevId: 240425622 -- 828dd49d392d83dbeecd9d3e9cb14551ab265905 by Jon Cohen : Add default link options to absl builds. Currently all this does is add -ignore:4221 to Abseil msvc builds, but the structure is all in place to add more link options when necessary Fix #277 Note: This CL changes tact for us in that it puts the default options in the helper function as opposed to the invocations of absl_cc_blah. The original intent of keeping these out of the helper functions was to make generating the CMakeLists.txt files have a smaller diff, but looking now that is a problem for the future, and small compared to making maintenance and use of our CMake buildsystem easier PiperOrigin-RevId: 240409463 -- 4aa120e9dcf76d29e9ca0008d0f6d4d9fa8abe8c by Matt Kulukundis : Reduce flake rate for non-determistic test to < 1/10,000 PiperOrigin-RevId: 240370938 -- bc30e219531827bfbf90915b2067c7fb8160bb6d by Derek Mauro : Add Bazel caching on Kokoro for new linux targets. PiperOrigin-RevId: 240356556 -- c4e06d79a50d7bb211312b7845c4bd92c0761747 by Jon Cohen : include AbseilInstallDirs instead of GNUInstallDirs. It worked before because global_CMakeLists.txt also included AbseilInstallDirs PiperOrigin-RevId: 240206409 -- c254dc6cade8a263f3f97fb1417d92fe5235ff32 by Jon Cohen : Fix logic for when we create the variant_exception_safety_test in CMake. Currently we are only running in on gcc > 4.9, when we want it run on every compiler except gcc <= 4.8 PiperOrigin-RevId: 240194174 -- 01518006b351d3670ba1d349cfbcb7dd6f3a8b84 by CJ Johnson : Removes old implementation warning comment now that InlinedVector has an implementation detail file PiperOrigin-RevId: 240167265 -- eb05355ae8c7397752ab7a65afc9e0a99472ba9d by Jon Cohen : Remove the forward declaration of Span PiperOrigin-RevId: 240156660 -- b7e75aa3933d6e79dd086821cf58d15e72f476f4 by Jon Cohen : Prepare CMake install rule for LTS releases: * Remove the warning against installing in system install locations * Insert versioning to keep different LTS installs from colliding. Headers are installed in /absl_$version/include, .a files in /absl_$version/lib, and config files in /absl_$version/lib/cmake PiperOrigin-RevId: 240153986 -- de63488ab6236e041f08260794b0b634a2b8ed16 by CJ Johnson : Reduce reader confusion by using std::addressof(...) even when the type is known to not overload operator&(...) PiperOrigin-RevId: 240131902 GitOrigin-RevId: f6c627ce4470a814adc377947b58346eef69a4c9 Change-Id: I95dbbacaaf65aceeeca9e9bee5fd9ea456225f62 --- absl/types/optional.h | 27 +++++++++++++-------------- 1 file changed, 13 insertions(+), 14 deletions(-) (limited to 'absl/types/optional.h') diff --git a/absl/types/optional.h b/absl/types/optional.h index f0ae9a17..6806160d 100644 --- a/absl/types/optional.h +++ b/absl/types/optional.h @@ -61,6 +61,7 @@ using std::nullopt; #include #include "absl/base/attributes.h" +#include "absl/base/internal/inline_variable.h" #include "absl/meta/type_traits.h" #include "absl/types/bad_optional_access.h" @@ -126,32 +127,30 @@ namespace absl { template class optional; +namespace optional_internal { + +// This tag type is used as a constructor parameter type for `nullopt_t`. +struct init_t { + explicit init_t() = default; +}; + +} // namespace optional_internal + // nullopt_t // // Class type for `absl::nullopt` used to indicate an `absl::optional` type // that does not contain a value. struct nullopt_t { - struct init_t {}; - static init_t init; - // It must not be default-constructible to avoid ambiguity for opt = {}. - // Note the non-const reference, which is to eliminate ambiguity for code - // like: - // - // struct S { int value; }; - // - // void Test() { - // optional opt; - // opt = {{}}; - // } - explicit constexpr nullopt_t(init_t& /*unused*/) {} + explicit constexpr nullopt_t(optional_internal::init_t) noexcept {} }; // nullopt // // A tag constant of type `absl::nullopt_t` used to indicate an empty // `absl::optional` in certain functions, such as construction or assignment. -extern const nullopt_t nullopt; +ABSL_INTERNAL_INLINE_CONSTEXPR(nullopt_t, nullopt, + nullopt_t(optional_internal::init_t())); namespace optional_internal { -- cgit v1.2.3