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Diffstat (limited to 'third_party/abseil_cpp/absl/status/status.h')
| -rw-r--r-- | third_party/abseil_cpp/absl/status/status.h | 428 |
1 files changed, 428 insertions, 0 deletions
diff --git a/third_party/abseil_cpp/absl/status/status.h b/third_party/abseil_cpp/absl/status/status.h new file mode 100644 index 0000000000..967e60644f --- /dev/null +++ b/third_party/abseil_cpp/absl/status/status.h @@ -0,0 +1,428 @@ +// Copyright 2019 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. +#ifndef ABSL_STATUS_STATUS_H_ +#define ABSL_STATUS_STATUS_H_ + +#include <iostream> +#include <string> + +#include "absl/container/inlined_vector.h" +#include "absl/strings/cord.h" +#include "absl/types/optional.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN + +enum class StatusCode : int { + kOk = 0, + kCancelled = 1, + kUnknown = 2, + kInvalidArgument = 3, + kDeadlineExceeded = 4, + kNotFound = 5, + kAlreadyExists = 6, + kPermissionDenied = 7, + kResourceExhausted = 8, + kFailedPrecondition = 9, + kAborted = 10, + kOutOfRange = 11, + kUnimplemented = 12, + kInternal = 13, + kUnavailable = 14, + kDataLoss = 15, + kUnauthenticated = 16, + kDoNotUseReservedForFutureExpansionUseDefaultInSwitchInstead_ = 20 +}; + +// Returns the name for the status code, or "" if it is an unknown value. +std::string StatusCodeToString(StatusCode code); + +// Streams StatusCodeToString(code) to `os`. +std::ostream& operator<<(std::ostream& os, StatusCode code); + +namespace status_internal { + +// Container for status payloads. +struct Payload { + std::string type_url; + absl::Cord payload; +}; + +using Payloads = absl::InlinedVector<Payload, 1>; + +// Reference-counted representation of Status data. +struct StatusRep { + std::atomic<int32_t> ref; + absl::StatusCode code; + std::string message; + std::unique_ptr<status_internal::Payloads> payloads; +}; + +absl::StatusCode MapToLocalCode(int value); +} // namespace status_internal + +class ABSL_MUST_USE_RESULT Status final { + public: + // Creates an OK status with no message or payload. + Status(); + + // Create a status in the canonical error space with the specified code and + // error message. If `code == absl::StatusCode::kOk`, `msg` is ignored and an + // object identical to an OK status is constructed. + // + // `msg` must be in UTF-8. The implementation may complain (e.g., + // by printing a warning) if it is not. + Status(absl::StatusCode code, absl::string_view msg); + + Status(const Status&); + Status& operator=(const Status& x); + + // Move operations. + // The moved-from state is valid but unspecified. + Status(Status&&) noexcept; + Status& operator=(Status&&); + + ~Status(); + + // If `this->ok()`, stores `new_status` into *this. If `!this->ok()`, + // preserves the current data. May, in the future, augment the current status + // with additional information about `new_status`. + // + // Convenient way of keeping track of the first error encountered. + // Instead of: + // if (overall_status.ok()) overall_status = new_status + // Use: + // overall_status.Update(new_status); + // + // Style guide exception for rvalue reference granted in CL 153567220. + void Update(const Status& new_status); + void Update(Status&& new_status); + + // Returns true if the Status is OK. + ABSL_MUST_USE_RESULT bool ok() const; + + // Returns the (canonical) error code. + absl::StatusCode code() const; + + // Returns the raw (canonical) error code which could be out of the range of + // the local `absl::StatusCode` enum. NOTE: This should only be called when + // converting to wire format. Use `code` for error handling. + int raw_code() const; + + // Returns the error message. Note: prefer ToString() for debug logging. + // This message rarely describes the error code. It is not unusual for the + // error message to be the empty string. + absl::string_view message() const; + + friend bool operator==(const Status&, const Status&); + friend bool operator!=(const Status&, const Status&); + + // Returns a combination of the error code name, the message and the payloads. + // You can expect the code name and the message to be substrings of the + // result, and the payloads to be printed by the registered printer extensions + // if they are recognized. + // WARNING: Do not depend on the exact format of the result of `ToString()` + // which is subject to change. + std::string ToString() const; + + // Ignores any errors. This method does nothing except potentially suppress + // complaints from any tools that are checking that errors are not dropped on + // the floor. + void IgnoreError() const; + + // Swap the contents of `a` with `b` + friend void swap(Status& a, Status& b); + + // Payload management APIs + + // Type URL should be unique and follow the naming convention below: + // The idea of type URL comes from `google.protobuf.Any` + // (https://developers.google.com/protocol-buffers/docs/proto3#any). The + // type URL should be globally unique and follow the format of URL + // (https://en.wikipedia.org/wiki/URL). The default type URL for a given + // protobuf message type is "type.googleapis.com/packagename.messagename". For + // other custom wire formats, users should define the format of type URL in a + // similar practice so as to minimize the chance of conflict between type + // URLs. Users should make sure that the type URL can be mapped to a concrete + // C++ type if they want to deserialize the payload and read it effectively. + + // Gets the payload based for `type_url` key, if it is present. + absl::optional<absl::Cord> GetPayload(absl::string_view type_url) const; + + // Sets the payload for `type_url` key for a non-ok status, overwriting any + // existing payload for `type_url`. + // + // NOTE: Does nothing if the Status is ok. + void SetPayload(absl::string_view type_url, absl::Cord payload); + + // Erases the payload corresponding to the `type_url` key. Returns true if + // the payload was present. + bool ErasePayload(absl::string_view type_url); + + // Iterates over the stored payloads and calls `visitor(type_key, payload)` + // for each one. + // + // NOTE: The order of calls to `visitor` is not specified and may change at + // any time. + // + // NOTE: Any mutation on the same 'Status' object during visitation is + // forbidden and could result in undefined behavior. + void ForEachPayload( + const std::function<void(absl::string_view, const absl::Cord&)>& visitor) + const; + + private: + friend Status CancelledError(); + + // Creates a status in the canonical error space with the specified + // code, and an empty error message. + explicit Status(absl::StatusCode code); + + static void UnrefNonInlined(uintptr_t rep); + static void Ref(uintptr_t rep); + static void Unref(uintptr_t rep); + + // REQUIRES: !ok() + // Ensures rep_ is not shared with any other Status. + void PrepareToModify(); + + const status_internal::Payloads* GetPayloads() const; + status_internal::Payloads* GetPayloads(); + + // Takes ownership of payload. + static uintptr_t NewRep(absl::StatusCode code, absl::string_view msg, + std::unique_ptr<status_internal::Payloads> payload); + static bool EqualsSlow(const absl::Status& a, const absl::Status& b); + + // MSVC 14.0 limitation requires the const. + static constexpr const char kMovedFromString[] = + "Status accessed after move."; + + static const std::string* EmptyString(); + static const std::string* MovedFromString(); + + // Returns whether rep contains an inlined representation. + // See rep_ for details. + static bool IsInlined(uintptr_t rep); + + // Indicates whether this Status was the rhs of a move operation. See rep_ + // for details. + static bool IsMovedFrom(uintptr_t rep); + static uintptr_t MovedFromRep(); + + // Convert between error::Code and the inlined uintptr_t representation used + // by rep_. See rep_ for details. + static uintptr_t CodeToInlinedRep(absl::StatusCode code); + static absl::StatusCode InlinedRepToCode(uintptr_t rep); + + // Converts between StatusRep* and the external uintptr_t representation used + // by rep_. See rep_ for details. + static uintptr_t PointerToRep(status_internal::StatusRep* r); + static status_internal::StatusRep* RepToPointer(uintptr_t r); + + // Returns string for non-ok Status. + std::string ToStringSlow() const; + + // Status supports two different representations. + // - When the low bit is off it is an inlined representation. + // It uses the canonical error space, no message or payload. + // The error code is (rep_ >> 2). + // The (rep_ & 2) bit is the "moved from" indicator, used in IsMovedFrom(). + // - When the low bit is on it is an external representation. + // In this case all the data comes from a heap allocated Rep object. + // (rep_ - 1) is a status_internal::StatusRep* pointer to that structure. + uintptr_t rep_; +}; + +// Returns an OK status, equivalent to a default constructed instance. +Status OkStatus(); + +// Prints a human-readable representation of `x` to `os`. +std::ostream& operator<<(std::ostream& os, const Status& x); + +// ----------------------------------------------------------------- +// Implementation details follow + +inline Status::Status() : rep_(CodeToInlinedRep(absl::StatusCode::kOk)) {} + +inline Status::Status(absl::StatusCode code) : rep_(CodeToInlinedRep(code)) {} + +inline Status::Status(const Status& x) : rep_(x.rep_) { Ref(rep_); } + +inline Status& Status::operator=(const Status& x) { + uintptr_t old_rep = rep_; + if (x.rep_ != old_rep) { + Ref(x.rep_); + rep_ = x.rep_; + Unref(old_rep); + } + return *this; +} + +inline Status::Status(Status&& x) noexcept : rep_(x.rep_) { + x.rep_ = MovedFromRep(); +} + +inline Status& Status::operator=(Status&& x) { + uintptr_t old_rep = rep_; + rep_ = x.rep_; + x.rep_ = MovedFromRep(); + Unref(old_rep); + return *this; +} + +inline void Status::Update(const Status& new_status) { + if (ok()) { + *this = new_status; + } +} + +inline void Status::Update(Status&& new_status) { + if (ok()) { + *this = std::move(new_status); + } +} + +inline Status::~Status() { Unref(rep_); } + +inline bool Status::ok() const { + return rep_ == CodeToInlinedRep(absl::StatusCode::kOk); +} + +inline absl::string_view Status::message() const { + return !IsInlined(rep_) + ? RepToPointer(rep_)->message + : (IsMovedFrom(rep_) ? absl::string_view(kMovedFromString) + : absl::string_view()); +} + +inline bool operator==(const Status& lhs, const Status& rhs) { + return lhs.rep_ == rhs.rep_ || Status::EqualsSlow(lhs, rhs); +} + +inline bool operator!=(const Status& lhs, const Status& rhs) { + return !(lhs == rhs); +} + +inline std::string Status::ToString() const { + return ok() ? "OK" : ToStringSlow(); +} + +inline void Status::IgnoreError() const { + // no-op +} + +inline void swap(absl::Status& a, absl::Status& b) { + using std::swap; + swap(a.rep_, b.rep_); +} + +inline const status_internal::Payloads* Status::GetPayloads() const { + return IsInlined(rep_) ? nullptr : RepToPointer(rep_)->payloads.get(); +} + +inline status_internal::Payloads* Status::GetPayloads() { + return IsInlined(rep_) ? nullptr : RepToPointer(rep_)->payloads.get(); +} + +inline bool Status::IsInlined(uintptr_t rep) { return (rep & 1) == 0; } + +inline bool Status::IsMovedFrom(uintptr_t rep) { + return IsInlined(rep) && (rep & 2) != 0; +} + +inline uintptr_t Status::MovedFromRep() { + return CodeToInlinedRep(absl::StatusCode::kInternal) | 2; +} + +inline uintptr_t Status::CodeToInlinedRep(absl::StatusCode code) { + return static_cast<uintptr_t>(code) << 2; +} + +inline absl::StatusCode Status::InlinedRepToCode(uintptr_t rep) { + assert(IsInlined(rep)); + return static_cast<absl::StatusCode>(rep >> 2); +} + +inline status_internal::StatusRep* Status::RepToPointer(uintptr_t rep) { + assert(!IsInlined(rep)); + return reinterpret_cast<status_internal::StatusRep*>(rep - 1); +} + +inline uintptr_t Status::PointerToRep(status_internal::StatusRep* rep) { + return reinterpret_cast<uintptr_t>(rep) + 1; +} + +inline void Status::Ref(uintptr_t rep) { + if (!IsInlined(rep)) { + RepToPointer(rep)->ref.fetch_add(1, std::memory_order_relaxed); + } +} + +inline void Status::Unref(uintptr_t rep) { + if (!IsInlined(rep)) { + UnrefNonInlined(rep); + } +} + +inline Status OkStatus() { return Status(); } + +// Each of the functions below creates a Status object with a particular error +// code and the given message. The error code of the returned status object +// matches the name of the function. +Status AbortedError(absl::string_view message); +Status AlreadyExistsError(absl::string_view message); +Status CancelledError(absl::string_view message); +Status DataLossError(absl::string_view message); +Status DeadlineExceededError(absl::string_view message); +Status FailedPreconditionError(absl::string_view message); +Status InternalError(absl::string_view message); +Status InvalidArgumentError(absl::string_view message); +Status NotFoundError(absl::string_view message); +Status OutOfRangeError(absl::string_view message); +Status PermissionDeniedError(absl::string_view message); +Status ResourceExhaustedError(absl::string_view message); +Status UnauthenticatedError(absl::string_view message); +Status UnavailableError(absl::string_view message); +Status UnimplementedError(absl::string_view message); +Status UnknownError(absl::string_view message); + +// Creates a `Status` object with the `absl::StatusCode::kCancelled` error code +// and an empty message. It is provided only for efficiency, given that +// message-less kCancelled errors are common in the infrastructure. +inline Status CancelledError() { return Status(absl::StatusCode::kCancelled); } + +// Each of the functions below returns true if the given status matches the +// error code implied by the function's name. +ABSL_MUST_USE_RESULT bool IsAborted(const Status& status); +ABSL_MUST_USE_RESULT bool IsAlreadyExists(const Status& status); +ABSL_MUST_USE_RESULT bool IsCancelled(const Status& status); +ABSL_MUST_USE_RESULT bool IsDataLoss(const Status& status); +ABSL_MUST_USE_RESULT bool IsDeadlineExceeded(const Status& status); +ABSL_MUST_USE_RESULT bool IsFailedPrecondition(const Status& status); +ABSL_MUST_USE_RESULT bool IsInternal(const Status& status); +ABSL_MUST_USE_RESULT bool IsInvalidArgument(const Status& status); +ABSL_MUST_USE_RESULT bool IsNotFound(const Status& status); +ABSL_MUST_USE_RESULT bool IsOutOfRange(const Status& status); +ABSL_MUST_USE_RESULT bool IsPermissionDenied(const Status& status); +ABSL_MUST_USE_RESULT bool IsResourceExhausted(const Status& status); +ABSL_MUST_USE_RESULT bool IsUnauthenticated(const Status& status); +ABSL_MUST_USE_RESULT bool IsUnavailable(const Status& status); +ABSL_MUST_USE_RESULT bool IsUnimplemented(const Status& status); +ABSL_MUST_USE_RESULT bool IsUnknown(const Status& status); + +ABSL_NAMESPACE_END +} // namespace absl + +#endif // ABSL_STATUS_STATUS_H_ |