summaryrefslogtreecommitdiff
path: root/absl/flags/internal/flag.h
diff options
context:
space:
mode:
Diffstat (limited to 'absl/flags/internal/flag.h')
-rw-r--r--absl/flags/internal/flag.h48
1 files changed, 28 insertions, 20 deletions
diff --git a/absl/flags/internal/flag.h b/absl/flags/internal/flag.h
index b5471fa8..c6c4a2f7 100644
--- a/absl/flags/internal/flag.h
+++ b/absl/flags/internal/flag.h
@@ -301,41 +301,44 @@ class FlagImpl {
bool IsSpecifiedOnCommandLine() const ABSL_LOCKS_EXCLUDED(*DataGuard());
std::string DefaultValue() const ABSL_LOCKS_EXCLUDED(*DataGuard());
std::string CurrentValue() const ABSL_LOCKS_EXCLUDED(*DataGuard());
- void Read(void* dst, const FlagOpFn dst_op) const
- ABSL_LOCKS_EXCLUDED(*DataGuard());
+ void Read(void* dst) const ABSL_LOCKS_EXCLUDED(*DataGuard());
// Attempts to parse supplied `value` std::string. If parsing is successful, then
// it replaces `dst` with the new value.
bool TryParse(void** dst, absl::string_view value, std::string* err) const
ABSL_EXCLUSIVE_LOCKS_REQUIRED(*DataGuard());
-#ifndef NDEBUG
- template <typename T>
- void Get(T* dst) const {
- Read(dst, &FlagOps<T>);
- }
-#else
template <typename T, typename std::enable_if<
!IsAtomicFlagTypeTrait<T>::value, int>::type = 0>
void Get(T* dst) const {
- Read(dst, &FlagOps<T>);
+ AssertValidType(&flags_internal::FlagOps<T>);
+ Read(dst);
}
// Overload for `GetFlag()` for types that support lock-free reads.
template <typename T, typename std::enable_if<IsAtomicFlagTypeTrait<T>::value,
int>::type = 0>
void Get(T* dst) const {
- using U = BestAtomicType<T>;
- const typename U::type r = value_.atomics.template load<T>();
+ // For flags of types which can be accessed "atomically" we want to avoid
+ // slowing down flag value access due to type validation. That's why
+ // this validation is hidden behind !NDEBUG
+#ifndef NDEBUG
+ AssertValidType(&flags_internal::FlagOps<T>);
+#endif
+ using U = flags_internal::BestAtomicType<T>;
+ typename U::type r = value_.atomics.template load<T>();
if (r != U::AtomicInit()) {
std::memcpy(static_cast<void*>(dst), &r, sizeof(T));
} else {
- Read(dst, &FlagOps<T>);
+ Read(dst);
}
}
-#endif
+ template <typename T>
+ void Set(const T& src) {
+ AssertValidType(&flags_internal::FlagOps<T>);
+ Write(&src);
+ }
// Mutating access methods
- void Write(const void* src, const FlagOpFn src_op)
- ABSL_LOCKS_EXCLUDED(*DataGuard());
+ void Write(const void* src) ABSL_LOCKS_EXCLUDED(*DataGuard());
bool SetFromString(absl::string_view value, FlagSettingMode set_mode,
ValueSource source, std::string* err)
ABSL_LOCKS_EXCLUDED(*DataGuard());
@@ -383,6 +386,13 @@ class FlagImpl {
ABSL_EXCLUSIVE_LOCKS_REQUIRED(*DataGuard()) {
return static_cast<FlagDefaultKind>(def_kind_);
}
+ // Used in read/write operations to validate source/target has correct type.
+ // For example if flag is declared as absl::Flag<int> FLAGS_foo, a call to
+ // absl::GetFlag(FLAGS_foo) validates that the type of FLAGS_foo is indeed
+ // int. To do that we pass the "assumed" type id (which is deduced from type
+ // int) as an argument `op`, which is in turn is validated against the type id
+ // stored in flag object by flag definition statement.
+ void AssertValidType(const flags_internal::FlagOpFn op) const;
// Immutable flag's state.
@@ -461,9 +471,7 @@ class Flag final : public flags_internal::CommandLineFlag {
impl_.Get(&u.value);
return std::move(u.value);
}
-
- void Set(const T& v) { impl_.Write(&v, &FlagOps<T>); }
-
+ void Set(const T& v) { impl_.Set(v); }
void SetCallback(const FlagCallbackFunc mutation_callback) {
impl_.SetCallback(mutation_callback);
}
@@ -509,10 +517,10 @@ class Flag final : public flags_internal::CommandLineFlag {
void Destroy() override { impl_.Destroy(); }
- void Read(void* dst) const override { impl_.Read(dst, &FlagOps<T>); }
+ void Read(void* dst) const override { impl_.Read(dst); }
FlagOpFn TypeId() const override { return &FlagOps<T>; }
- // Flag's implementation with value type abstracted out.
+ // Flag's data
FlagImpl impl_;
};