145 lines
4.7 KiB
Diff
145 lines
4.7 KiB
Diff
diff -up chromium-65.0.3325.146/base/optional.h.ncnm chromium-65.0.3325.146/base/optional.h
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--- chromium-65.0.3325.146/base/optional.h.ncnm 2018-03-13 22:40:11.743226276 -0400
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+++ chromium-65.0.3325.146/base/optional.h 2018-03-13 22:44:30.948211358 -0400
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@@ -240,37 +240,37 @@ class OptionalBase {
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~OptionalBase() = default;
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OptionalBase& operator=(const OptionalBase& other) {
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- if (!other.storage_.is_populated_) {
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- FreeIfNeeded();
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- return *this;
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- }
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-
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- InitOrAssign(other.storage_.value_);
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+ CopyAssign(other);
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return *this;
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}
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OptionalBase& operator=(OptionalBase&& other) {
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- if (!other.storage_.is_populated_) {
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- FreeIfNeeded();
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- return *this;
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- }
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-
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- InitOrAssign(std::move(other.storage_.value_));
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+ MoveAssign(std::move(other));
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return *this;
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}
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- void InitOrAssign(const T& value) {
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- if (!storage_.is_populated_)
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- storage_.Init(value);
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+ template <typename U>
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+ void CopyAssign(const OptionalBase<U>& other) {
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+ if (other.storage_.is_populated_)
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+ InitOrAssign(other.storage_.value_);
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else
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- storage_.value_ = value;
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+ FreeIfNeeded();
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}
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- void InitOrAssign(T&& value) {
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- if (!storage_.is_populated_)
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- storage_.Init(std::move(value));
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+ template <typename U>
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+ void MoveAssign(OptionalBase<U>&& other) {
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+ if (other.storage_.is_populated_)
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+ InitOrAssign(std::move(other.storage_.value_));
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+ else
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+ FreeIfNeeded();
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+ }
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+
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+ template <typename U>
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+ void InitOrAssign(U&& value) {
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+ if (storage_.is_populated_)
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+ storage_.value_ = std::forward<U>(value);
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else
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- storage_.value_ = std::move(value);
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+ storage_.Init(std::forward<U>(value));
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}
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void FreeIfNeeded() {
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@@ -340,7 +340,7 @@ struct MoveAssignable<false> {
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MoveAssignable& operator=(MoveAssignable&&) = delete;
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};
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-// Helper to conditionally enable converting constructors.
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+// Helper to conditionally enable converting constructors and assign operators.
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template <typename T, typename U>
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struct IsConvertibleFromOptional
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: std::integral_constant<
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@@ -354,6 +354,16 @@ struct IsConvertibleFromOptional
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std::is_convertible<Optional<U>&&, T>::value ||
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std::is_convertible<const Optional<U>&&, T>::value> {};
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+template <typename T, typename U>
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+struct IsAssignableFromOptional
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+ : std::integral_constant<
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+ bool,
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+ IsConvertibleFromOptional<T, U>::value ||
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+ std::is_assignable<T&, Optional<U>&>::value ||
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+ std::is_assignable<T&, const Optional<U>&>::value ||
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+ std::is_assignable<T&, Optional<U>&&>::value ||
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+ std::is_assignable<T&, const Optional<U>&&>::value> {};
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+
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// Forward compatibility for C++20.
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template <typename T>
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using RemoveCvRefT = std::remove_cv_t<std::remove_reference_t<T>>;
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@@ -487,14 +497,42 @@ class Optional
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return *this;
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}
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- template <class U>
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- typename std::enable_if<std::is_same<std::decay_t<U>, T>::value,
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- Optional&>::type
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+ // Perfect-forwarded assignment.
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+ template <typename U>
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+ std::enable_if_t<
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+ !std::is_same<internal::RemoveCvRefT<U>, Optional<T>>::value &&
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+ std::is_constructible<T, U>::value &&
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+ std::is_assignable<T&, U>::value &&
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+ (!std::is_scalar<T>::value ||
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+ !std::is_same<std::decay_t<U>, T>::value),
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+ Optional&>
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operator=(U&& value) {
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InitOrAssign(std::forward<U>(value));
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return *this;
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}
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+// Copy assign the state of other.
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+ template <typename U>
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+ std::enable_if_t<!internal::IsAssignableFromOptional<T, U>::value &&
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+ std::is_constructible<T, const U&>::value &&
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+ std::is_assignable<T&, const U&>::value,
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+ Optional&>
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+ operator=(const Optional<U>& other) {
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+ CopyAssign(other);
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+ return *this;
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+ }
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+
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+ // Move assign the state of other.
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+ template <typename U>
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+ std::enable_if_t<!internal::IsAssignableFromOptional<T, U>::value &&
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+ std::is_constructible<T, U>::value &&
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+ std::is_assignable<T&, U>::value,
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+ Optional&>
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+ operator=(Optional<U>&& other) {
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+ MoveAssign(std::move(other));
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+ return *this;
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+ }
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+
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constexpr const T* operator->() const {
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DCHECK(storage_.is_populated_);
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return &value();
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@@ -606,8 +644,10 @@ class Optional
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private:
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// Accessing template base class's protected member needs explicit
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// declaration to do so.
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+ using internal::OptionalBase<T>::CopyAssign;
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using internal::OptionalBase<T>::FreeIfNeeded;
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using internal::OptionalBase<T>::InitOrAssign;
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+ using internal::OptionalBase<T>::MoveAssign;
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using internal::OptionalBase<T>::storage_;
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};
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