Lifetime checks for `absl::StrSplit()`
PiperOrigin-RevId: 537400816
Change-Id: I06794a6b8b6a441e34121047024380190d42869a
diff --git a/absl/strings/internal/str_split_internal.h b/absl/strings/internal/str_split_internal.h
index 35edf3a..081ad85 100644
--- a/absl/strings/internal/str_split_internal.h
+++ b/absl/strings/internal/str_split_internal.h
@@ -235,6 +235,24 @@
HasMappedType<C>::value> {
};
+template <typename StringType, typename Container, typename = void>
+struct ShouldUseLifetimeBound : std::false_type {};
+
+template <typename StringType, typename Container>
+struct ShouldUseLifetimeBound<
+ StringType, Container,
+ std::enable_if_t<
+ std::is_same<StringType, std::string>::value &&
+ std::is_same<typename Container::value_type, absl::string_view>::value>>
+ : std::true_type {};
+
+template <typename StringType, typename First, typename Second>
+using ShouldUseLifetimeBoundForPair = std::integral_constant<
+ bool, std::is_same<StringType, std::string>::value &&
+ (std::is_same<First, absl::string_view>::value ||
+ std::is_same<Second, absl::string_view>::value)>;
+
+
// This class implements the range that is returned by absl::StrSplit(). This
// class has templated conversion operators that allow it to be implicitly
// converted to a variety of types that the caller may have specified on the
@@ -281,10 +299,24 @@
// An implicit conversion operator that is restricted to only those containers
// that the splitter is convertible to.
- template <typename Container,
- typename = typename std::enable_if<
- SplitterIsConvertibleTo<Container>::value>::type>
- operator Container() const { // NOLINT(runtime/explicit)
+ template <
+ typename Container,
+ std::enable_if_t<ShouldUseLifetimeBound<StringType, Container>::value &&
+ SplitterIsConvertibleTo<Container>::value,
+ std::nullptr_t> = nullptr>
+ // NOLINTNEXTLINE(google-explicit-constructor)
+ operator Container() const ABSL_ATTRIBUTE_LIFETIME_BOUND {
+ return ConvertToContainer<Container, typename Container::value_type,
+ HasMappedType<Container>::value>()(*this);
+ }
+
+ template <
+ typename Container,
+ std::enable_if_t<!ShouldUseLifetimeBound<StringType, Container>::value &&
+ SplitterIsConvertibleTo<Container>::value,
+ std::nullptr_t> = nullptr>
+ // NOLINTNEXTLINE(google-explicit-constructor)
+ operator Container() const {
return ConvertToContainer<Container, typename Container::value_type,
HasMappedType<Container>::value>()(*this);
}
@@ -293,8 +325,27 @@
// strings returned by the begin() iterator. Either/both of .first and .second
// will be constructed with empty strings if the iterator doesn't have a
// corresponding value.
+ template <typename First, typename Second,
+ std::enable_if_t<
+ ShouldUseLifetimeBoundForPair<StringType, First, Second>::value,
+ std::nullptr_t> = nullptr>
+ // NOLINTNEXTLINE(google-explicit-constructor)
+ operator std::pair<First, Second>() const ABSL_ATTRIBUTE_LIFETIME_BOUND {
+ return ConvertToPair<First, Second>();
+ }
+
+ template <typename First, typename Second,
+ std::enable_if_t<!ShouldUseLifetimeBoundForPair<StringType, First,
+ Second>::value,
+ std::nullptr_t> = nullptr>
+ // NOLINTNEXTLINE(google-explicit-constructor)
+ operator std::pair<First, Second>() const {
+ return ConvertToPair<First, Second>();
+ }
+
+ private:
template <typename First, typename Second>
- operator std::pair<First, Second>() const { // NOLINT(runtime/explicit)
+ std::pair<First, Second> ConvertToPair() const {
absl::string_view first, second;
auto it = begin();
if (it != end()) {
@@ -306,7 +357,6 @@
return {First(first), Second(second)};
}
- private:
// ConvertToContainer is a functor converting a Splitter to the requested
// Container of ValueType. It is specialized below to optimize splitting to
// certain combinations of Container and ValueType.
