761 lines
26 KiB
C++
761 lines
26 KiB
C++
// Copyright 2020 The Abseil Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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// -----------------------------------------------------------------------------
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// File: statusor.h
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// -----------------------------------------------------------------------------
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//
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// An `absl::StatusOr<T>` represents a union of an `absl::Status` object
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// and an object of type `T`. The `absl::StatusOr<T>` will either contain an
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// object of type `T` (indicating a successful operation), or an error (of type
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// `absl::Status`) explaining why such a value is not present.
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//
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// In general, check the success of an operation returning an
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// `absl::StatusOr<T>` like you would an `absl::Status` by using the `ok()`
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// member function.
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//
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// Example:
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//
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// StatusOr<Foo> result = Calculation();
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// if (result.ok()) {
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// result->DoSomethingCool();
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// } else {
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// LOG(ERROR) << result.status();
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// }
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#ifndef ABSL_STATUS_STATUSOR_H_
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#define ABSL_STATUS_STATUSOR_H_
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#include <exception>
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#include <initializer_list>
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#include <new>
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#include <string>
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#include <type_traits>
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#include <utility>
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#include "absl/base/attributes.h"
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#include "absl/meta/type_traits.h"
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#include "absl/status/internal/statusor_internal.h"
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#include "absl/status/status.h"
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#include "absl/types/variant.h"
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#include "absl/utility/utility.h"
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namespace absl {
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ABSL_NAMESPACE_BEGIN
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// BadStatusOrAccess
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//
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// This class defines the type of object to throw (if exceptions are enabled),
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// when accessing the value of an `absl::StatusOr<T>` object that does not
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// contain a value. This behavior is analogous to that of
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// `std::bad_optional_access` in the case of accessing an invalid
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// `std::optional` value.
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//
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// Example:
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//
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// try {
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// absl::StatusOr<int> v = FetchInt();
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// DoWork(v.value()); // Accessing value() when not "OK" may throw
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// } catch (absl::BadStatusOrAccess& ex) {
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// LOG(ERROR) << ex.status();
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// }
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class BadStatusOrAccess : public std::exception {
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public:
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explicit BadStatusOrAccess(absl::Status status);
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~BadStatusOrAccess() override;
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// BadStatusOrAccess::what()
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//
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// Returns the associated explanatory string of the `absl::StatusOr<T>`
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// object's error code. This function only returns the string literal "Bad
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// StatusOr Access" for cases when evaluating general exceptions.
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//
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// The pointer of this string is guaranteed to be valid until any non-const
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// function is invoked on the exception object.
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const char* what() const noexcept override;
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// BadStatusOrAccess::status()
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//
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// Returns the associated `absl::Status` of the `absl::StatusOr<T>` object's
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// error.
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const absl::Status& status() const;
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private:
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absl::Status status_;
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};
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// Returned StatusOr objects may not be ignored.
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template <typename T>
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class ABSL_MUST_USE_RESULT StatusOr;
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// absl::StatusOr<T>
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//
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// The `absl::StatusOr<T>` class template is a union of an `absl::Status` object
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// and an object of type `T`. The `absl::StatusOr<T>` models an object that is
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// either a usable object, or an error (of type `absl::Status`) explaining why
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// such an object is not present. An `absl::StatusOr<T>` is typically the return
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// value of a function which may fail.
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//
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// An `absl::StatusOr<T>` can never hold an "OK" status (an
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// `absl::StatusCode::kOk` value); instead, the presence of an object of type
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// `T` indicates success. Instead of checking for a `kOk` value, use the
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// `absl::StatusOr<T>::ok()` member function. (It is for this reason, and code
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// readability, that using the `ok()` function is preferred for `absl::Status`
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// as well.)
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//
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// Example:
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//
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// StatusOr<Foo> result = DoBigCalculationThatCouldFail();
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// if (result.ok()) {
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// result->DoSomethingCool();
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// } else {
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// LOG(ERROR) << result.status();
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// }
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//
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// Accessing the object held by an `absl::StatusOr<T>` should be performed via
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// `operator*` or `operator->`, after a call to `ok()` confirms that the
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// `absl::StatusOr<T>` holds an object of type `T`:
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//
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// Example:
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//
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// absl::StatusOr<int> i = GetCount();
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// if (i.ok()) {
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// updated_total += *i
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// }
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//
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// NOTE: using `absl::StatusOr<T>::value()` when no valid value is present will
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// throw an exception if exceptions are enabled or terminate the process when
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// execeptions are not enabled.
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//
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// Example:
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//
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// StatusOr<Foo> result = DoBigCalculationThatCouldFail();
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// const Foo& foo = result.value(); // Crash/exception if no value present
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// foo.DoSomethingCool();
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//
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// A `absl::StatusOr<T*>` can be constructed from a null pointer like any other
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// pointer value, and the result will be that `ok()` returns `true` and
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// `value()` returns `nullptr`. Checking the value of pointer in an
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// `absl::StatusOr<T>` generally requires a bit more care, to ensure both that a
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// value is present and that value is not null:
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//
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// StatusOr<std::unique_ptr<Foo>> result = FooFactory::MakeNewFoo(arg);
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// if (!result.ok()) {
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// LOG(ERROR) << result.status();
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// } else if (*result == nullptr) {
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// LOG(ERROR) << "Unexpected null pointer";
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// } else {
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// (*result)->DoSomethingCool();
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// }
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//
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// Example factory implementation returning StatusOr<T>:
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//
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// StatusOr<Foo> FooFactory::MakeFoo(int arg) {
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// if (arg <= 0) {
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// return absl::Status(absl::StatusCode::kInvalidArgument,
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// "Arg must be positive");
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// }
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// return Foo(arg);
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// }
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template <typename T>
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class StatusOr : private internal_statusor::StatusOrData<T>,
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private internal_statusor::CopyCtorBase<T>,
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private internal_statusor::MoveCtorBase<T>,
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private internal_statusor::CopyAssignBase<T>,
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private internal_statusor::MoveAssignBase<T> {
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template <typename U>
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friend class StatusOr;
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typedef internal_statusor::StatusOrData<T> Base;
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public:
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// StatusOr<T>::value_type
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//
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// This instance data provides a generic `value_type` member for use within
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// generic programming. This usage is analogous to that of
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// `optional::value_type` in the case of `std::optional`.
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typedef T value_type;
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// Constructors
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// Constructs a new `absl::StatusOr` with an `absl::StatusCode::kUnknown`
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// status. This constructor is marked 'explicit' to prevent usages in return
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// values such as 'return {};', under the misconception that
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// `absl::StatusOr<std::vector<int>>` will be initialized with an empty
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// vector, instead of an `absl::StatusCode::kUnknown` error code.
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explicit StatusOr();
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// `StatusOr<T>` is copy constructible if `T` is copy constructible.
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StatusOr(const StatusOr&) = default;
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// `StatusOr<T>` is copy assignable if `T` is copy constructible and copy
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// assignable.
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StatusOr& operator=(const StatusOr&) = default;
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// `StatusOr<T>` is move constructible if `T` is move constructible.
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StatusOr(StatusOr&&) = default;
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// `StatusOr<T>` is moveAssignable if `T` is move constructible and move
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// assignable.
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StatusOr& operator=(StatusOr&&) = default;
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// Converting Constructors
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// Constructs a new `absl::StatusOr<T>` from an `absl::StatusOr<U>`, when `T`
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// is constructible from `U`. To avoid ambiguity, these constructors are
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// disabled if `T` is also constructible from `StatusOr<U>.`. This constructor
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// is explicit if and only if the corresponding construction of `T` from `U`
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// is explicit. (This constructor inherits its explicitness from the
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// underlying constructor.)
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template <
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typename U,
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absl::enable_if_t<
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absl::conjunction<
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absl::negation<std::is_same<T, U>>,
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std::is_constructible<T, const U&>,
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std::is_convertible<const U&, T>,
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absl::negation<
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internal_statusor::IsConstructibleOrConvertibleFromStatusOr<
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T, U>>>::value,
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int> = 0>
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StatusOr(const StatusOr<U>& other) // NOLINT
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: Base(static_cast<const typename StatusOr<U>::Base&>(other)) {}
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template <
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typename U,
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absl::enable_if_t<
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absl::conjunction<
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absl::negation<std::is_same<T, U>>,
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std::is_constructible<T, const U&>,
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absl::negation<std::is_convertible<const U&, T>>,
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absl::negation<
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internal_statusor::IsConstructibleOrConvertibleFromStatusOr<
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T, U>>>::value,
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int> = 0>
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explicit StatusOr(const StatusOr<U>& other)
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: Base(static_cast<const typename StatusOr<U>::Base&>(other)) {}
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template <
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typename U,
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absl::enable_if_t<
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absl::conjunction<
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absl::negation<std::is_same<T, U>>, std::is_constructible<T, U&&>,
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std::is_convertible<U&&, T>,
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absl::negation<
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internal_statusor::IsConstructibleOrConvertibleFromStatusOr<
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T, U>>>::value,
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int> = 0>
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StatusOr(StatusOr<U>&& other) // NOLINT
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: Base(static_cast<typename StatusOr<U>::Base&&>(other)) {}
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template <
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typename U,
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absl::enable_if_t<
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absl::conjunction<
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absl::negation<std::is_same<T, U>>, std::is_constructible<T, U&&>,
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absl::negation<std::is_convertible<U&&, T>>,
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absl::negation<
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internal_statusor::IsConstructibleOrConvertibleFromStatusOr<
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T, U>>>::value,
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int> = 0>
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explicit StatusOr(StatusOr<U>&& other)
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: Base(static_cast<typename StatusOr<U>::Base&&>(other)) {}
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// Converting Assignment Operators
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// Creates an `absl::StatusOr<T>` through assignment from an
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// `absl::StatusOr<U>` when:
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//
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// * Both `absl::StatusOr<T>` and `absl::StatusOr<U>` are OK by assigning
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// `U` to `T` directly.
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// * `absl::StatusOr<T>` is OK and `absl::StatusOr<U>` contains an error
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// code by destroying `absl::StatusOr<T>`'s value and assigning from
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// `absl::StatusOr<U>'
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// * `absl::StatusOr<T>` contains an error code and `absl::StatusOr<U>` is
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// OK by directly initializing `T` from `U`.
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// * Both `absl::StatusOr<T>` and `absl::StatusOr<U>` contain an error
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// code by assigning the `Status` in `absl::StatusOr<U>` to
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// `absl::StatusOr<T>`
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//
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// These overloads only apply if `absl::StatusOr<T>` is constructible and
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// assignable from `absl::StatusOr<U>` and `StatusOr<T>` cannot be directly
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// assigned from `StatusOr<U>`.
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template <
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typename U,
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absl::enable_if_t<
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absl::conjunction<
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absl::negation<std::is_same<T, U>>,
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std::is_constructible<T, const U&>,
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std::is_assignable<T, const U&>,
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absl::negation<
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internal_statusor::
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IsConstructibleOrConvertibleOrAssignableFromStatusOr<
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T, U>>>::value,
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int> = 0>
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StatusOr& operator=(const StatusOr<U>& other) {
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this->Assign(other);
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return *this;
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}
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template <
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typename U,
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absl::enable_if_t<
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absl::conjunction<
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absl::negation<std::is_same<T, U>>, std::is_constructible<T, U&&>,
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std::is_assignable<T, U&&>,
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absl::negation<
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internal_statusor::
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IsConstructibleOrConvertibleOrAssignableFromStatusOr<
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T, U>>>::value,
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int> = 0>
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StatusOr& operator=(StatusOr<U>&& other) {
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this->Assign(std::move(other));
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return *this;
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}
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// Constructs a new `absl::StatusOr<T>` with a non-ok status. After calling
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// this constructor, `this->ok()` will be `false` and calls to `value()` will
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// crash, or produce an exception if exceptions are enabled.
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//
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// The constructor also takes any type `U` that is convertible to
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// `absl::Status`. This constructor is explicit if an only if `U` is not of
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// type `absl::Status` and the conversion from `U` to `Status` is explicit.
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//
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// REQUIRES: !Status(std::forward<U>(v)).ok(). This requirement is DCHECKed.
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// In optimized builds, passing absl::OkStatus() here will have the effect
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// of passing absl::StatusCode::kInternal as a fallback.
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template <
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typename U = absl::Status,
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absl::enable_if_t<
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absl::conjunction<
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std::is_convertible<U&&, absl::Status>,
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std::is_constructible<absl::Status, U&&>,
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absl::negation<std::is_same<absl::decay_t<U>, absl::StatusOr<T>>>,
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absl::negation<std::is_same<absl::decay_t<U>, T>>,
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absl::negation<std::is_same<absl::decay_t<U>, absl::in_place_t>>,
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absl::negation<internal_statusor::HasConversionOperatorToStatusOr<
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T, U&&>>>::value,
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int> = 0>
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StatusOr(U&& v) : Base(std::forward<U>(v)) {}
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template <
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typename U = absl::Status,
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absl::enable_if_t<
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absl::conjunction<
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absl::negation<std::is_convertible<U&&, absl::Status>>,
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std::is_constructible<absl::Status, U&&>,
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absl::negation<std::is_same<absl::decay_t<U>, absl::StatusOr<T>>>,
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absl::negation<std::is_same<absl::decay_t<U>, T>>,
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absl::negation<std::is_same<absl::decay_t<U>, absl::in_place_t>>,
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absl::negation<internal_statusor::HasConversionOperatorToStatusOr<
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T, U&&>>>::value,
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int> = 0>
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explicit StatusOr(U&& v) : Base(std::forward<U>(v)) {}
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template <
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typename U = absl::Status,
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absl::enable_if_t<
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absl::conjunction<
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std::is_convertible<U&&, absl::Status>,
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std::is_constructible<absl::Status, U&&>,
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absl::negation<std::is_same<absl::decay_t<U>, absl::StatusOr<T>>>,
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absl::negation<std::is_same<absl::decay_t<U>, T>>,
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absl::negation<std::is_same<absl::decay_t<U>, absl::in_place_t>>,
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absl::negation<internal_statusor::HasConversionOperatorToStatusOr<
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T, U&&>>>::value,
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int> = 0>
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StatusOr& operator=(U&& v) {
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this->AssignStatus(std::forward<U>(v));
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return *this;
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}
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// Perfect-forwarding value assignment operator.
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// If `*this` contains a `T` value before the call, the contained value is
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// assigned from `std::forward<U>(v)`; Otherwise, it is directly-initialized
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// from `std::forward<U>(v)`.
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// This function does not participate in overload unless:
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// 1. `std::is_constructible_v<T, U>` is true,
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// 2. `std::is_assignable_v<T&, U>` is true.
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// 3. `std::is_same_v<StatusOr<T>, std::remove_cvref_t<U>>` is false.
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// 4. Assigning `U` to `T` is not ambiguous:
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// If `U` is `StatusOr<V>` and `T` is constructible and assignable from
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// both `StatusOr<V>` and `V`, the assignment is considered bug-prone and
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// ambiguous thus will fail to compile. For example:
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// StatusOr<bool> s1 = true; // s1.ok() && *s1 == true
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// StatusOr<bool> s2 = false; // s2.ok() && *s2 == false
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// s1 = s2; // ambiguous, `s1 = *s2` or `s1 = bool(s2)`?
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template <
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typename U = T,
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typename = typename std::enable_if<absl::conjunction<
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std::is_constructible<T, U&&>, std::is_assignable<T&, U&&>,
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absl::disjunction<
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std::is_same<absl::remove_cv_t<absl::remove_reference_t<U>>, T>,
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absl::conjunction<
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absl::negation<std::is_convertible<U&&, absl::Status>>,
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absl::negation<internal_statusor::
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HasConversionOperatorToStatusOr<T, U&&>>>>,
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internal_statusor::IsForwardingAssignmentValid<T, U&&>>::value>::type>
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StatusOr& operator=(U&& v) {
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this->Assign(std::forward<U>(v));
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return *this;
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}
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// Constructs the inner value `T` in-place using the provided args, using the
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// `T(args...)` constructor.
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template <typename... Args>
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explicit StatusOr(absl::in_place_t, Args&&... args);
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template <typename U, typename... Args>
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explicit StatusOr(absl::in_place_t, std::initializer_list<U> ilist,
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Args&&... args);
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// Constructs the inner value `T` in-place using the provided args, using the
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// `T(U)` (direct-initialization) constructor. This constructor is only valid
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// if `T` can be constructed from a `U`. Can accept move or copy constructors.
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//
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// This constructor is explicit if `U` is not convertible to `T`. To avoid
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// ambiguity, this constuctor is disabled if `U` is a `StatusOr<J>`, where `J`
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// is convertible to `T`.
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template <
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typename U = T,
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absl::enable_if_t<
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absl::conjunction<
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internal_statusor::IsDirectInitializationValid<T, U&&>,
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std::is_constructible<T, U&&>, std::is_convertible<U&&, T>,
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absl::disjunction<
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std::is_same<absl::remove_cv_t<absl::remove_reference_t<U>>,
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T>,
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absl::conjunction<
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absl::negation<std::is_convertible<U&&, absl::Status>>,
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absl::negation<
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internal_statusor::HasConversionOperatorToStatusOr<
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T, U&&>>>>>::value,
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int> = 0>
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StatusOr(U&& u) // NOLINT
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: StatusOr(absl::in_place, std::forward<U>(u)) {
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}
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template <
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typename U = T,
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absl::enable_if_t<
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absl::conjunction<
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internal_statusor::IsDirectInitializationValid<T, U&&>,
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absl::disjunction<
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std::is_same<absl::remove_cv_t<absl::remove_reference_t<U>>,
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T>,
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absl::conjunction<
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absl::negation<std::is_constructible<absl::Status, U&&>>,
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absl::negation<
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internal_statusor::HasConversionOperatorToStatusOr<
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T, U&&>>>>,
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std::is_constructible<T, U&&>,
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absl::negation<std::is_convertible<U&&, T>>>::value,
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int> = 0>
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explicit StatusOr(U&& u) // NOLINT
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: StatusOr(absl::in_place, std::forward<U>(u)) {
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}
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// StatusOr<T>::ok()
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//
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// Returns whether or not this `absl::StatusOr<T>` holds a `T` value. This
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// member function is analagous to `absl::Status::ok()` and should be used
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// similarly to check the status of return values.
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//
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// Example:
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//
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// StatusOr<Foo> result = DoBigCalculationThatCouldFail();
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// if (result.ok()) {
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// // Handle result
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// else {
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// // Handle error
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// }
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ABSL_MUST_USE_RESULT bool ok() const { return this->status_.ok(); }
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// StatusOr<T>::status()
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//
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// Returns a reference to the current `absl::Status` contained within the
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// `absl::StatusOr<T>`. If `absl::StatusOr<T>` contains a `T`, then this
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// function returns `absl::OkStatus()`.
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const Status& status() const &;
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Status status() &&;
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// StatusOr<T>::value()
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//
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// Returns a reference to the held value if `this->ok()`. Otherwise, throws
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// `absl::BadStatusOrAccess` if exceptions are enabled, or is guaranteed to
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// terminate the process if exceptions are disabled.
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//
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// If you have already checked the status using `this->ok()`, you probably
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// want to use `operator*()` or `operator->()` to access the value instead of
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// `value`.
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//
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// Note: for value types that are cheap to copy, prefer simple code:
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//
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// T value = statusor.value();
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//
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// Otherwise, if the value type is expensive to copy, but can be left
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// in the StatusOr, simply assign to a reference:
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//
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// T& value = statusor.value(); // or `const T&`
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//
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// Otherwise, if the value type supports an efficient move, it can be
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// used as follows:
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//
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// T value = std::move(statusor).value();
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//
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// The `std::move` on statusor instead of on the whole expression enables
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// warnings about possible uses of the statusor object after the move.
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const T& value() const&;
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T& value() &;
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const T&& value() const&&;
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T&& value() &&;
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// StatusOr<T>:: operator*()
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//
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// Returns a reference to the current value.
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//
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// REQUIRES: `this->ok() == true`, otherwise the behavior is undefined.
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//
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// Use `this->ok()` to verify that there is a current value within the
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// `absl::StatusOr<T>`. Alternatively, see the `value()` member function for a
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// similar API that guarantees crashing or throwing an exception if there is
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// no current value.
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const T& operator*() const&;
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T& operator*() &;
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const T&& operator*() const&&;
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T&& operator*() &&;
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// StatusOr<T>::operator->()
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//
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// Returns a pointer to the current value.
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//
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// REQUIRES: `this->ok() == true`, otherwise the behavior is undefined.
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//
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// Use `this->ok()` to verify that there is a current value.
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const T* operator->() const;
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T* operator->();
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// StatusOr<T>::value_or()
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//
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// Returns the current value if `this->ok() == true`. Otherwise constructs a
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// value using the provided `default_value`.
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//
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// Unlike `value`, this function returns by value, copying the current value
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// if necessary. If the value type supports an efficient move, it can be used
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// as follows:
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//
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// T value = std::move(statusor).value_or(def);
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//
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// Unlike with `value`, calling `std::move()` on the result of `value_or` will
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// still trigger a copy.
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template <typename U>
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T value_or(U&& default_value) const&;
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template <typename U>
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T value_or(U&& default_value) &&;
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// StatusOr<T>::IgnoreError()
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//
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// Ignores any errors. This method does nothing except potentially suppress
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// complaints from any tools that are checking that errors are not dropped on
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// the floor.
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void IgnoreError() const;
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// StatusOr<T>::emplace()
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//
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// Reconstructs the inner value T in-place using the provided args, using the
|
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// T(args...) constructor. Returns reference to the reconstructed `T`.
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|
template <typename... Args>
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T& emplace(Args&&... args) {
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if (ok()) {
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this->Clear();
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this->MakeValue(std::forward<Args>(args)...);
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} else {
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this->MakeValue(std::forward<Args>(args)...);
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this->status_ = absl::OkStatus();
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|
}
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|
return this->data_;
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|
}
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|
|
|
template <
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typename U, typename... Args,
|
|
absl::enable_if_t<
|
|
std::is_constructible<T, std::initializer_list<U>&, Args&&...>::value,
|
|
int> = 0>
|
|
T& emplace(std::initializer_list<U> ilist, Args&&... args) {
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if (ok()) {
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|
this->Clear();
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|
this->MakeValue(ilist, std::forward<Args>(args)...);
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|
} else {
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|
this->MakeValue(ilist, std::forward<Args>(args)...);
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this->status_ = absl::OkStatus();
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|
}
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|
return this->data_;
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}
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private:
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using internal_statusor::StatusOrData<T>::Assign;
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template <typename U>
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|
void Assign(const absl::StatusOr<U>& other);
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template <typename U>
|
|
void Assign(absl::StatusOr<U>&& other);
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};
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// operator==()
|
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//
|
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// This operator checks the equality of two `absl::StatusOr<T>` objects.
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template <typename T>
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bool operator==(const StatusOr<T>& lhs, const StatusOr<T>& rhs) {
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if (lhs.ok() && rhs.ok()) return *lhs == *rhs;
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return lhs.status() == rhs.status();
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}
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// operator!=()
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|
//
|
|
// This operator checks the inequality of two `absl::StatusOr<T>` objects.
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template <typename T>
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|
bool operator!=(const StatusOr<T>& lhs, const StatusOr<T>& rhs) {
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return !(lhs == rhs);
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}
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//------------------------------------------------------------------------------
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// Implementation details for StatusOr<T>
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//------------------------------------------------------------------------------
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|
// TODO(sbenza): avoid the string here completely.
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template <typename T>
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StatusOr<T>::StatusOr() : Base(Status(absl::StatusCode::kUnknown, "")) {}
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template <typename T>
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template <typename U>
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inline void StatusOr<T>::Assign(const StatusOr<U>& other) {
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if (other.ok()) {
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this->Assign(*other);
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} else {
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|
this->AssignStatus(other.status());
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|
}
|
|
}
|
|
|
|
template <typename T>
|
|
template <typename U>
|
|
inline void StatusOr<T>::Assign(StatusOr<U>&& other) {
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|
if (other.ok()) {
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this->Assign(*std::move(other));
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|
} else {
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|
this->AssignStatus(std::move(other).status());
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|
}
|
|
}
|
|
template <typename T>
|
|
template <typename... Args>
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|
StatusOr<T>::StatusOr(absl::in_place_t, Args&&... args)
|
|
: Base(absl::in_place, std::forward<Args>(args)...) {}
|
|
|
|
template <typename T>
|
|
template <typename U, typename... Args>
|
|
StatusOr<T>::StatusOr(absl::in_place_t, std::initializer_list<U> ilist,
|
|
Args&&... args)
|
|
: Base(absl::in_place, ilist, std::forward<Args>(args)...) {}
|
|
|
|
template <typename T>
|
|
const Status& StatusOr<T>::status() const & { return this->status_; }
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|
template <typename T>
|
|
Status StatusOr<T>::status() && {
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|
return ok() ? OkStatus() : std::move(this->status_);
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|
}
|
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template <typename T>
|
|
const T& StatusOr<T>::value() const& {
|
|
if (!this->ok()) internal_statusor::ThrowBadStatusOrAccess(this->status_);
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|
return this->data_;
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|
}
|
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|
template <typename T>
|
|
T& StatusOr<T>::value() & {
|
|
if (!this->ok()) internal_statusor::ThrowBadStatusOrAccess(this->status_);
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return this->data_;
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|
}
|
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|
|
template <typename T>
|
|
const T&& StatusOr<T>::value() const&& {
|
|
if (!this->ok()) {
|
|
internal_statusor::ThrowBadStatusOrAccess(std::move(this->status_));
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|
}
|
|
return std::move(this->data_);
|
|
}
|
|
|
|
template <typename T>
|
|
T&& StatusOr<T>::value() && {
|
|
if (!this->ok()) {
|
|
internal_statusor::ThrowBadStatusOrAccess(std::move(this->status_));
|
|
}
|
|
return std::move(this->data_);
|
|
}
|
|
|
|
template <typename T>
|
|
const T& StatusOr<T>::operator*() const& {
|
|
this->EnsureOk();
|
|
return this->data_;
|
|
}
|
|
|
|
template <typename T>
|
|
T& StatusOr<T>::operator*() & {
|
|
this->EnsureOk();
|
|
return this->data_;
|
|
}
|
|
|
|
template <typename T>
|
|
const T&& StatusOr<T>::operator*() const&& {
|
|
this->EnsureOk();
|
|
return std::move(this->data_);
|
|
}
|
|
|
|
template <typename T>
|
|
T&& StatusOr<T>::operator*() && {
|
|
this->EnsureOk();
|
|
return std::move(this->data_);
|
|
}
|
|
|
|
template <typename T>
|
|
const T* StatusOr<T>::operator->() const {
|
|
this->EnsureOk();
|
|
return &this->data_;
|
|
}
|
|
|
|
template <typename T>
|
|
T* StatusOr<T>::operator->() {
|
|
this->EnsureOk();
|
|
return &this->data_;
|
|
}
|
|
|
|
template <typename T>
|
|
template <typename U>
|
|
T StatusOr<T>::value_or(U&& default_value) const& {
|
|
if (ok()) {
|
|
return this->data_;
|
|
}
|
|
return std::forward<U>(default_value);
|
|
}
|
|
|
|
template <typename T>
|
|
template <typename U>
|
|
T StatusOr<T>::value_or(U&& default_value) && {
|
|
if (ok()) {
|
|
return std::move(this->data_);
|
|
}
|
|
return std::forward<U>(default_value);
|
|
}
|
|
|
|
template <typename T>
|
|
void StatusOr<T>::IgnoreError() const {
|
|
// no-op
|
|
}
|
|
|
|
ABSL_NAMESPACE_END
|
|
} // namespace absl
|
|
|
|
#endif // ABSL_STATUS_STATUSOR_H_
|