Add 'third_party/abseil_cpp/' from commit '768eb2ca2857342673fcd462792ce04b8bac3fa3' r/781

git-subtree-dir: third_party/abseil_cpp
git-subtree-mainline: ffb2ae54beb5796cd408fbe15d2d2da09ff37adf
git-subtree-split: 768eb2ca2857342673fcd462792ce04b8bac3fa3

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 000000000000..967e60644f60
--- /dev/null
+++ b/third_party/abseil_cpp/absl/status/status.h
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+// 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_