maurice/snix
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Export of internal Abseil changes.

Browse source 
--
ed3a3431eee9e48e6553b0320e0308d2dde6725c by Derek Mauro <dmauro@google.com>:

Project import generated by Copybara.

PiperOrigin-RevId: 258631680
GitOrigin-RevId: ed3a3431eee9e48e6553b0320e0308d2dde6725c
Change-Id: I1d7ae86a79783842092d29504605ba039c369603
This commit is contained in:
Abseil Team 2019-07-17 16:35:47 -04:00 • committed by Derek Mauro
parent 44efe96dfc
commit c6c3c1b498
32 changed files with 1168 additions and 657 deletions
Download patch file Download diff file Expand all files Collapse all files

51
absl/flags/flag.h
View file

@ -91,30 +91,7 @@ T GetFlag(const absl::Flag<T>& flag) {
ABSL_FLAGS_INTERNAL_FOR_EACH_LOCK_FREE(ABSL_FLAGS_INTERNAL_LOCK_FREE_VALIDATE)
#undef ABSL_FLAGS_INTERNAL_LOCK_FREE_VALIDATE
// Implementation notes:
//
// We are wrapping a union around the value of `T` to serve three purposes:
//
// 1. `U.value` has correct size and alignment for a value of type `T`
// 2. The `U.value` constructor is not invoked since U's constructor does not
// do it explicitly.
// 3. The `U.value` destructor is invoked since U's destructor does it
// explicitly. This makes `U` a kind of RAII wrapper around non default
// constructible value of T, which is destructed when we leave the scope.
// We do need to destroy U.value, which is constructed by
// CommandLineFlag::Read even though we left it in a moved-from state
// after std::move.
//
// All of this serves to avoid requiring `T` being default constructible.
union U {
T value;
U() {}
~U() { value.~T(); }
};
U u;
flag.internal.Read(&u.value, &flags_internal::FlagOps<T>);
return std::move(u.value);
return flag.Get();
}
// Overload for `GetFlag()` for types that support lock-free reads.
@ -132,7 +109,7 @@ ABSL_FLAGS_INTERNAL_FOR_EACH_LOCK_FREE(ABSL_FLAGS_INTERNAL_LOCK_FREE_EXPORT)
// but especially within performance-critical code.
template <typename T>
void SetFlag(absl::Flag<T>* flag, const T& v) {
flag->internal.Write(&v, &flags_internal::FlagOps<T>);
flag->Set(v);
}
// Overload of `SetFlag()` to allow callers to pass in a value that is
@ -141,7 +118,7 @@ void SetFlag(absl::Flag<T>* flag, const T& v) {
template <typename T, typename V>
void SetFlag(absl::Flag<T>* flag, const V& v) {
T value(v);
SetFlag<T>(flag, value);
flag->Set(value);
}
} // namespace absl
@ -239,17 +216,17 @@ void SetFlag(absl::Flag<T>* flag, const V& v) {
// Note: Name of registrar object is not arbitrary. It is used to "grab"
// global name for FLAGS_no<flag_name> symbol, thus preventing the possibility
// of defining two flags with names foo and nofoo.
#define ABSL_FLAG_IMPL(Type, name, default_value, help) \
namespace absl {} \
ABSL_FLAG_IMPL_DECLARE_DEF_VAL_WRAPPER(name, Type, default_value) \
ABSL_FLAG_IMPL_DECLARE_HELP_WRAPPER(name, help) \
absl::Flag<Type> FLAGS_##name( \
ABSL_FLAG_IMPL_FLAGNAME(#name), \
&AbslFlagsWrapHelp##name, \
ABSL_FLAG_IMPL_FILENAME(), \
&absl::flags_internal::FlagMarshallingOps<Type>, \
&AbslFlagsInitFlag##name); \
extern bool FLAGS_no##name; \
#define ABSL_FLAG_IMPL(Type, name, default_value, help) \
namespace absl {} \
ABSL_FLAG_IMPL_DECLARE_DEF_VAL_WRAPPER(name, Type, default_value) \
ABSL_FLAG_IMPL_DECLARE_HELP_WRAPPER(name, help) \
absl::Flag<Type> FLAGS_##name( \
ABSL_FLAG_IMPL_FLAGNAME(#name), \
&AbslFlagsWrapHelp##name, \
ABSL_FLAG_IMPL_FILENAME(), \
&absl::flags_internal::FlagMarshallingOps<Type>, \
&AbslFlagsInitFlag##name); \
extern bool FLAGS_no##name; \
bool FLAGS_no##name = ABSL_FLAG_IMPL_REGISTRAR(Type, FLAGS_##name)
// ABSL_RETIRED_FLAG