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authorGravatar Abseil Team <absl-team@google.com>2020-02-04 14:18:00 -0800
committerGravatar Andy Getz <durandal@google.com>2020-02-04 17:25:42 -0500
commit08a7e7bf972c8451855a5022f2faf3d3655db015 (patch)
treeb5e687db133d38fb9023420505f7527d937b99d6 /absl/flags
parent36bcd9599b3f48c99357ba61cf33584889306d6a (diff)
Export of internal Abseil changes
-- 1bc4d36e13fb9175ea8cdaa00213aa9d4417c669 by Andy Getzendanner <durandal@google.com>: Fix pointer format specifier in documentation Import of https://github.com/abseil/abseil-cpp/pull/614 PiperOrigin-RevId: 293227540 -- c7b43b30493c4fb5f2ec3264672b08bfe1ea3709 by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 293160245 -- 64439365e2b4a0b5e51ae0a7dafdb15912402dfd by Shahriar Rouf <nafi@google.com>: Add benchmarks for string_view: BM_CompareFirstOneLess and BM_CompareSecondOneLess. PiperOrigin-RevId: 293031676 -- b273b420cab24a6e3f487430987e09f4eb1caec4 by Greg Falcon <gfalcon@google.com>: Remove an unreachable line from charconv.cc. Fixes github issue #613. PiperOrigin-RevId: 292980167 -- 70babb5f7a3d9fdd00a2b3085c3c2b9fe0265c79 by Gennadiy Rozental <rogeeff@google.com>: Move GetFlag implementation into FlagImpl. This change will allow us to hide details of GetFlag overloads inside implementation detais. Eventually we'll migrate to a different implementation. No semantic changes in this CL. PiperOrigin-RevId: 292930847 -- 94bee7b7cc31e0167ee4b953281c1e78c96a574a by Abseil Team <absl-team@google.com>: Clarification in absl::Exponential documentation. PiperOrigin-RevId: 292912672 -- d6916d30c5c1d3ee9ae46d69ec0a166a760c99c7 by Derek Mauro <dmauro@google.com>: Make AtomicHook constant-initializable on Clang for Windows. Only mark AtomicHook as constant-initializable on platforms where it is actually constant-initializable. PiperOrigin-RevId: 292655939 GitOrigin-RevId: 1bc4d36e13fb9175ea8cdaa00213aa9d4417c669 Change-Id: I090b231a0ca0d92868e494ab5b3fa86c902889d5
Diffstat (limited to 'absl/flags')
-rw-r--r--absl/flags/flag.h33
-rw-r--r--absl/flags/internal/flag.h28
2 files changed, 27 insertions, 34 deletions
diff --git a/absl/flags/flag.h b/absl/flags/flag.h
index bd61668f..fcfdd58c 100644
--- a/absl/flags/flag.h
+++ b/absl/flags/flag.h
@@ -186,15 +186,17 @@ class Flag {
//
// // FLAGS_firstname is a Flag of type `std::string`
// std::string first_name = absl::GetFlag(FLAGS_firstname);
+template <typename T>
+ABSL_MUST_USE_RESULT T GetFlag(const absl::Flag<T>& flag) {
+ return flag.Get();
+}
+
#ifndef NDEBUG
// We want to validate the type mismatch between type definition and
// declaration. The lock-free implementation does not allow us to do it,
// so in debug builds we always use the slower implementation, which always
// validates the type.
-template <typename T>
-ABSL_MUST_USE_RESULT T GetFlag(const absl::Flag<T>& flag) {
- return flag.Get();
-}
+
// We currently need an external linkage for built-in types because shared
// libraries have different addresses of flags_internal::FlagOps<T> which
// might cause log spam when checking the same flag type.
@@ -202,29 +204,6 @@ ABSL_MUST_USE_RESULT T GetFlag(const absl::Flag<T>& flag) {
ABSL_MUST_USE_RESULT T GetFlag(const absl::Flag<T>& flag);
ABSL_FLAGS_INTERNAL_BUILTIN_TYPES(ABSL_FLAGS_INTERNAL_BUILT_IN_EXPORT)
#undef ABSL_FLAGS_INTERNAL_BUILT_IN_EXPORT
-#else
-template <typename T,
- typename std::enable_if<
- !flags_internal::IsAtomicFlagTypeTrait<T>::value, int>::type = 0>
-ABSL_MUST_USE_RESULT T GetFlag(const absl::Flag<T>& flag) {
- return flag.Get();
-}
-// Overload for `GetFlag()` for types that support lock-free reads.
-template <typename T,
- typename std::enable_if<
- flags_internal::IsAtomicFlagTypeTrait<T>::value, int>::type = 0>
-ABSL_MUST_USE_RESULT T GetFlag(const absl::Flag<T>& flag) {
- // T might not be default constructible.
- union U {
- T value;
- U() {}
- };
- U result;
- if (flag.AtomicGet(&result.value)) {
- return result.value;
- }
- return flag.Get();
-}
#endif
// SetFlag()
diff --git a/absl/flags/internal/flag.h b/absl/flags/internal/flag.h
index ec467c31..4341f113 100644
--- a/absl/flags/internal/flag.h
+++ b/absl/flags/internal/flag.h
@@ -244,16 +244,32 @@ class FlagImpl {
bool TryParse(void** dst, absl::string_view value, std::string* err) const
ABSL_EXCLUSIVE_LOCKS_REQUIRED(*DataGuard());
+#ifndef NDEBUG
template <typename T>
- bool AtomicGet(T* v) const {
+ void Get(T* dst) const {
+ Read(dst, &flags_internal::FlagOps<T>);
+ }
+#else
+ template <typename T, typename std::enable_if<
+ !flags_internal::IsAtomicFlagTypeTrait<T>::value,
+ int>::type = 0>
+ void Get(T* dst) const {
+ Read(dst, &flags_internal::FlagOps<T>);
+ }
+ // Overload for `GetFlag()` for types that support lock-free reads.
+ template <typename T,
+ typename std::enable_if<
+ flags_internal::IsAtomicFlagTypeTrait<T>::value, int>::type = 0>
+ void Get(T* dst) const {
using U = flags_internal::BestAtomicType<T>;
const typename U::type r = atomics_.template load<T>();
if (r != U::AtomicInit()) {
- std::memcpy(static_cast<void*>(v), &r, sizeof(T));
- return true;
+ std::memcpy(static_cast<void*>(dst), &r, sizeof(T));
+ } else {
+ Read(dst, &flags_internal::FlagOps<T>);
}
- return false;
}
+#endif
// Mutating access methods
void Write(const void* src, const flags_internal::FlagOpFn src_op)
@@ -397,12 +413,10 @@ class Flag final : public flags_internal::CommandLineFlag {
};
U u;
- impl_.Read(&u.value, &flags_internal::FlagOps<T>);
+ impl_.Get(&u.value);
return std::move(u.value);
}
- bool AtomicGet(T* v) const { return impl_.AtomicGet(v); }
-
void Set(const T& v) { impl_.Write(&v, &flags_internal::FlagOps<T>); }
void SetCallback(const flags_internal::FlagCallback mutation_callback) {