From 529666594951b86604730a8b400f71d7eedd1e85 Mon Sep 17 00:00:00 2001 From: rsgowman Date: Mon, 19 Mar 2018 10:19:20 -0400 Subject: Add Status and StatusOr (#935) * Pull in status files from tensorflow * Add missing dependency to immutable library --- .../firebase/firestore/immutable/CMakeLists.txt | 2 + .../src/firebase/firestore/util/CMakeLists.txt | 5 + .../src/firebase/firestore/util/firebase_assert.h | 11 +- .../core/src/firebase/firestore/util/status.cc | 135 +++++++++ .../core/src/firebase/firestore/util/status.h | 143 +++++++++ .../core/src/firebase/firestore/util/statusor.cc | 41 +++ .../core/src/firebase/firestore/util/statusor.h | 322 +++++++++++++++++++++ .../firebase/firestore/util/statusor_internals.h | 258 +++++++++++++++++ 8 files changed, 912 insertions(+), 5 deletions(-) create mode 100644 Firestore/core/src/firebase/firestore/util/status.cc create mode 100644 Firestore/core/src/firebase/firestore/util/status.h create mode 100644 Firestore/core/src/firebase/firestore/util/statusor.cc create mode 100644 Firestore/core/src/firebase/firestore/util/statusor.h create mode 100644 Firestore/core/src/firebase/firestore/util/statusor_internals.h (limited to 'Firestore/core/src') diff --git a/Firestore/core/src/firebase/firestore/immutable/CMakeLists.txt b/Firestore/core/src/firebase/firestore/immutable/CMakeLists.txt index e8a95cd..4079307 100644 --- a/Firestore/core/src/firebase/firestore/immutable/CMakeLists.txt +++ b/Firestore/core/src/firebase/firestore/immutable/CMakeLists.txt @@ -18,4 +18,6 @@ cc_library( array_sorted_map.cc array_sorted_map.h map_entry.h + DEPENDS + firebase_firestore_util ) diff --git a/Firestore/core/src/firebase/firestore/util/CMakeLists.txt b/Firestore/core/src/firebase/firestore/util/CMakeLists.txt index 3e32111..7a080d4 100644 --- a/Firestore/core/src/firebase/firestore/util/CMakeLists.txt +++ b/Firestore/core/src/firebase/firestore/util/CMakeLists.txt @@ -118,6 +118,11 @@ cc_library( ordered_code.cc ordered_code.h secure_random.h + status.cc + status.h + statusor.cc + statusor.h + statusor_internals.h string_util.cc string_util.h DEPENDS diff --git a/Firestore/core/src/firebase/firestore/util/firebase_assert.h b/Firestore/core/src/firebase/firestore/util/firebase_assert.h index 76768e6..20c8429 100644 --- a/Firestore/core/src/firebase/firestore/util/firebase_assert.h +++ b/Firestore/core/src/firebase/firestore/util/firebase_assert.h @@ -23,6 +23,7 @@ #include #include "Firestore/core/src/firebase/firestore/util/log.h" +#include "absl/base/attributes.h" #define FIREBASE_EXPAND_STRINGIFY_(X) #X #define FIREBASE_EXPAND_STRINGIFY(X) FIREBASE_EXPAND_STRINGIFY_(X) @@ -107,11 +108,11 @@ namespace firestore { namespace util { // A no-return helper function. To raise an assertion, use Macro instead. -void FailAssert(const char* file, - const char* func, - const int line, - const char* format, - ...); +ABSL_ATTRIBUTE_NORETURN void FailAssert(const char* file, + const char* func, + const int line, + const char* format, + ...); } // namespace util } // namespace firestore diff --git a/Firestore/core/src/firebase/firestore/util/status.cc b/Firestore/core/src/firebase/firestore/util/status.cc new file mode 100644 index 0000000..0863139 --- /dev/null +++ b/Firestore/core/src/firebase/firestore/util/status.cc @@ -0,0 +1,135 @@ +/* + * Copyright 2015, 2018 Google + * + * 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 + * + * http://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. + */ + +#include "Firestore/core/src/firebase/firestore/util/status.h" + +#include "Firestore/core/src/firebase/firestore/util/string_printf.h" + +namespace firebase { +namespace firestore { +namespace util { + +Status::Status(FirestoreErrorCode code, absl::string_view msg) { + FIREBASE_ASSERT(code != FirestoreErrorCode::Ok); + state_ = std::unique_ptr(new State); + state_->code = code; + state_->msg = static_cast(msg); +} + +void Status::Update(const Status& new_status) { + if (ok()) { + *this = new_status; + } +} + +void Status::SlowCopyFrom(const State* src) { + if (src == nullptr) { + state_ = nullptr; + } else { + state_ = std::unique_ptr(new State(*src)); + } +} + +const std::string& Status::empty_string() { + static std::string* empty = new std::string; + return *empty; +} + +std::string Status::ToString() const { + if (state_ == nullptr) { + return "OK"; + } else { + std::string result; + switch (code()) { + case FirestoreErrorCode::Cancelled: + result = "Cancelled"; + break; + case FirestoreErrorCode::Unknown: + result = "Unknown"; + break; + case FirestoreErrorCode::InvalidArgument: + result = "Invalid argument"; + break; + case FirestoreErrorCode::DeadlineExceeded: + result = "Deadline exceeded"; + break; + case FirestoreErrorCode::NotFound: + result = "Not found"; + break; + case FirestoreErrorCode::AlreadyExists: + result = "Already exists"; + break; + case FirestoreErrorCode::PermissionDenied: + result = "Permission denied"; + break; + case FirestoreErrorCode::Unauthenticated: + result = "Unauthenticated"; + break; + case FirestoreErrorCode::ResourceExhausted: + result = "Resource exhausted"; + break; + case FirestoreErrorCode::FailedPrecondition: + result = "Failed precondition"; + break; + case FirestoreErrorCode::Aborted: + result = "Aborted"; + break; + case FirestoreErrorCode::OutOfRange: + result = "Out of range"; + break; + case FirestoreErrorCode::Unimplemented: + result = "Unimplemented"; + break; + case FirestoreErrorCode::Internal: + result = "Internal"; + break; + case FirestoreErrorCode::Unavailable: + result = "Unavailable"; + break; + case FirestoreErrorCode::DataLoss: + result = "Data loss"; + break; + default: + result = StringPrintf("Unknown code(%d)", static_cast(code())); + break; + } + result += ": "; + result += state_->msg; + return result; + } +} + +void Status::IgnoreError() const { + // no-op +} + +std::ostream& operator<<(std::ostream& os, const Status& x) { + os << x.ToString(); + return os; +} + +std::string StatusCheckOpHelperOutOfLine(const Status& v, const char* msg) { + FIREBASE_ASSERT(!v.ok()); + std::string r("Non-OK-status: "); + r += msg; + r += " status: "; + r += v.ToString(); + return r; +} + +} // namespace util +} // namespace firestore +} // namespace firebase diff --git a/Firestore/core/src/firebase/firestore/util/status.h b/Firestore/core/src/firebase/firestore/util/status.h new file mode 100644 index 0000000..0a65aa3 --- /dev/null +++ b/Firestore/core/src/firebase/firestore/util/status.h @@ -0,0 +1,143 @@ +/* + * Copyright 2015, 2018 Google + * + * 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 + * + * http://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 FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_UTIL_STATUS_H_ +#define FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_UTIL_STATUS_H_ + +#include +#include +#include +#include + +#include "Firestore/core/include/firebase/firestore/firestore_errors.h" +#include "Firestore/core/src/firebase/firestore/util/firebase_assert.h" +#include "absl/base/attributes.h" +#include "absl/strings/string_view.h" + +namespace firebase { +namespace firestore { +namespace util { + +/// Denotes success or failure of a call. +class ABSL_MUST_USE_RESULT Status { + public: + /// Create a success status. + Status() { + } + + /// \brief Create a status with the specified error code and msg as a + /// human-readable string containing more detailed information. + Status(FirestoreErrorCode code, absl::string_view msg); + + /// Copy the specified status. + Status(const Status& s); + void operator=(const Status& s); + + static Status OK() { + return Status(); + } + + /// Returns true iff the status indicates success. + bool ok() const { + return (state_ == nullptr); + } + + FirestoreErrorCode code() const { + return ok() ? FirestoreErrorCode::Ok : state_->code; + } + + const std::string& error_message() const { + return ok() ? empty_string() : state_->msg; + } + + bool operator==(const Status& x) const; + bool operator!=(const Status& x) const; + + /// \brief If `ok()`, stores `new_status` into `*this`. If `!ok()`, + /// preserves the current status, but may augment 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);` + void Update(const Status& new_status); + + /// \brief Return a string representation of this status suitable for + /// printing. Returns the string `"OK"` for success. + 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; + + private: + static const std::string& empty_string(); + struct State { + FirestoreErrorCode code; + std::string msg; + }; + // OK status has a `NULL` state_. Otherwise, `state_` points to + // a `State` structure containing the error code and message(s) + std::unique_ptr state_; + + void SlowCopyFrom(const State* src); +}; + +inline Status::Status(const Status& s) + : state_((s.state_ == nullptr) ? nullptr : new State(*s.state_)) { +} + +inline void Status::operator=(const Status& s) { + // The following condition catches both aliasing (when this == &s), + // and the common case where both s and *this are ok. + if (state_ != s.state_) { + SlowCopyFrom(s.state_.get()); + } +} + +inline bool Status::operator==(const Status& x) const { + return (this->state_ == x.state_) || (ToString() == x.ToString()); +} + +inline bool Status::operator!=(const Status& x) const { + return !(*this == x); +} + +std::ostream& operator<<(std::ostream& os, const Status& x); + +typedef std::function StatusCallback; + +extern std::string StatusCheckOpHelperOutOfLine(const Status& v, + const char* msg); + +#define STATUS_CHECK_OK(val) \ + FIREBASE_ASSERT_MESSAGE_WITH_EXPRESSION( \ + val.ok(), val.ok(), StatusCheckOpHelperOutOfLine(val, #val).c_str()) + +// DEBUG only version of STATUS_CHECK_OK. Compiler still parses 'val' even in +// opt mode. +#define STATUS_DCHECK_OK(val) \ + FIREBASE_DEV_ASSERT_MESSAGE_WITH_EXPRESSION( \ + val.ok(), val.ok(), StatusCheckOpHelperOutOfLine(val, #val).c_str()) + +} // namespace util +} // namespace firestore +} // namespace firebase + +#endif // FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_UTIL_STATUS_H_ diff --git a/Firestore/core/src/firebase/firestore/util/statusor.cc b/Firestore/core/src/firebase/firestore/util/statusor.cc new file mode 100644 index 0000000..be1e03a --- /dev/null +++ b/Firestore/core/src/firebase/firestore/util/statusor.cc @@ -0,0 +1,41 @@ +/* + * Copyright 2017, 2018 Google + * + * 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 + * + * http://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. + */ + +#include "Firestore/core/src/firebase/firestore/util/statusor.h" + +namespace firebase { +namespace firestore { +namespace util { +namespace internal_statusor { + +void Helper::HandleInvalidStatusCtorArg(Status* status) { + const char* kMessage = + "An OK status is not a valid constructor argument to StatusOr"; + FIREBASE_DEV_ASSERT_MESSAGE(false, kMessage); + // Fall back to Internal for non-debug builds + *status = Status(FirestoreErrorCode::Internal, kMessage); +} + +void Helper::Crash(const Status& status) { + FIREBASE_ASSERT_MESSAGE( + false, "Attempting to fetch value instead of handling error ", + status.ToString().c_str()); +} + +} // namespace internal_statusor +} // namespace util +} // namespace firestore +} // namespace firebase diff --git a/Firestore/core/src/firebase/firestore/util/statusor.h b/Firestore/core/src/firebase/firestore/util/statusor.h new file mode 100644 index 0000000..dc5644a --- /dev/null +++ b/Firestore/core/src/firebase/firestore/util/statusor.h @@ -0,0 +1,322 @@ +/* + * Copyright 2017, 2018 Google + * + * 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 + * + * http://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. + */ + +// StatusOr is the union of a Status object and a T +// object. StatusOr models the concept of an object that is either a +// usable value, or an error Status explaining why such a value is +// not present. To this end, StatusOr does not allow its Status +// value to be Status::OK. Furthermore, the value of a StatusOr +// must not be null. This is enforced by a debug check in most cases, +// but even when it is not, clients must not set the value to null. +// +// The primary use-case for StatusOr is as the return value of a +// function which may fail. +// +// Example client usage for a StatusOr, where T is not a pointer: +// +// StatusOr result = DoBigCalculationThatCouldFail(); +// if (result.ok()) { +// float answer = result.ValueOrDie(); +// printf("Big calculation yielded: %f", answer); +// } else { +// LOG(ERROR) << result.status(); +// } +// +// Example client usage for a StatusOr: +// +// StatusOr result = FooFactory::MakeNewFoo(arg); +// if (result.ok()) { +// std::unique_ptr foo(result.ValueOrDie()); +// foo->DoSomethingCool(); +// } else { +// LOG(ERROR) << result.status(); +// } +// +// Example client usage for a StatusOr>: +// +// StatusOr> result = FooFactory::MakeNewFoo(arg); +// if (result.ok()) { +// std::unique_ptr foo = std::move(result.ValueOrDie()); +// foo->DoSomethingCool(); +// } else { +// LOG(ERROR) << result.status(); +// } +// +// Example factory implementation returning StatusOr: +// +// StatusOr FooFactory::MakeNewFoo(int arg) { +// if (arg <= 0) { +// return tensorflow::InvalidArgument("Arg must be positive"); +// } else { +// return new Foo(arg); +// } +// } +// +// Note that the assignment operators require that destroying the currently +// stored value cannot invalidate the argument; in other words, the argument +// cannot be an alias for the current value, or anything owned by the current +// value. + +#ifndef FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_UTIL_STATUSOR_H_ +#define FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_UTIL_STATUSOR_H_ + +#include + +#include "Firestore/core/include/firebase/firestore/firestore_errors.h" +#include "Firestore/core/src/firebase/firestore/util/status.h" +#include "Firestore/core/src/firebase/firestore/util/statusor_internals.h" +#include "absl/base/attributes.h" +#include "absl/strings/string_view.h" + +namespace firebase { +namespace firestore { +namespace util { + +template +class ABSL_MUST_USE_RESULT StatusOr + : private internal_statusor::StatusOrData, + private internal_statusor::TraitsBase< + std::is_copy_constructible::value, + std::is_move_constructible::value> { + template + friend class StatusOr; + + typedef internal_statusor::StatusOrData Base; + + public: + typedef T element_type; + + // Constructs a new StatusOr with FirebaseErrorCode::Unknown status. This is + // marked 'explicit' to try to catch cases like 'return {};', where people + // think StatusOr> will be initialized with an empty vector, + // instead of a FirebaseErrorCode::Unknown status. + explicit StatusOr(); // NOLINT: allow explicit zero-parameter ctor + + // StatusOr will be copy constructible/assignable if T is copy + // constructible. + StatusOr(const StatusOr&) = default; + StatusOr& operator=(const StatusOr&) = default; + + // StatusOr will be move constructible/assignable if T is move + // constructible. + StatusOr(StatusOr&&) = default; + StatusOr& operator=(StatusOr&&) = default; + + // Conversion copy/move constructor, T must be convertible from U. + // TODO(b/62186717): These should not participate in overload resolution if U + // is not convertible to T. + template + StatusOr(const StatusOr& other); + template + StatusOr(StatusOr&& other); + + // Conversion copy/move assignment operator, T must be convertible from U. + template + StatusOr& operator=(const StatusOr& other); + template + StatusOr& operator=(StatusOr&& other); + + // Constructs a new StatusOr with the given value. After calling this + // constructor, calls to ValueOrDie() will succeed, and calls to status() will + // return OK. + // + // NOTE: Not explicit - we want to use StatusOr as a return type + // so it is convenient and sensible to be able to do 'return T()' + // when the return type is StatusOr. + // + // REQUIRES: T is copy constructible. + StatusOr(const T& value); // NOLINT: allow non-explicit 1-param ctor + + // Constructs a new StatusOr with the given non-ok status. After calling + // this constructor, calls to ValueOrDie() will CHECK-fail. + // + // NOTE: Not explicit - we want to use StatusOr as a return + // value, so it is convenient and sensible to be able to do 'return + // Status()' when the return type is StatusOr. + // + // REQUIRES: !status.ok(). This requirement is DCHECKed. + // In optimized builds, passing Status::OK() here will have the effect + // of passing tensorflow::error::INTERNAL as a fallback. + StatusOr(const Status& status); // NOLINT: allow non-explicit 1-param ctor + StatusOr& operator=(const Status& status); + + // TODO(b/62186997): Add operator=(T) overloads. + + // Similar to the `const T&` overload. + // + // REQUIRES: T is move constructible. + StatusOr(T&& value); // NOLINT: allow non-explicit 1-param ctor + + // RValue versions of the operations declared above. + StatusOr(Status&& status); // NOLINT: allow non-explicit 1-param ctor + StatusOr& operator=(Status&& status); + + // Returns this->status().ok() + bool ok() const { + return this->status_.ok(); + } + + // Returns a reference to our status. If this contains a T, then + // returns Status::OK(). + const Status& status() const&; + Status status() &&; + + // Returns a reference to our current value, or CHECK-fails if !this->ok(). + // + // Note: for value types that are cheap to copy, prefer simple code: + // + // T value = statusor.ValueOrDie(); + // + // Otherwise, if the value type is expensive to copy, but can be left + // in the StatusOr, simply assign to a reference: + // + // T& value = statusor.ValueOrDie(); // or `const T&` + // + // Otherwise, if the value type supports an efficient move, it can be + // used as follows: + // + // T value = std::move(statusor).ValueOrDie(); + // + // The std::move on statusor instead of on the whole expression enables + // warnings about possible uses of the statusor object after the move. + // C++ style guide waiver for ref-qualified overloads granted in cl/143176389 + // See go/ref-qualifiers for more details on such overloads. + const T& ValueOrDie() const&; + T& ValueOrDie() &; + const T&& ValueOrDie() const&&; + T&& ValueOrDie() &&; + + T ConsumeValueOrDie() { + return std::move(ValueOrDie()); + } + + // 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; +}; + +//////////////////////////////////////////////////////////////////////////////// +// Implementation details for StatusOr + +template +StatusOr::StatusOr() : Base(Status(FirestoreErrorCode::Unknown, "")) { +} + +template +StatusOr::StatusOr(const T& value) : Base(value) { +} + +template +StatusOr::StatusOr(const Status& status) : Base(status) { +} + +template +StatusOr& StatusOr::operator=(const Status& status) { + this->Assign(status); + return *this; +} + +template +StatusOr::StatusOr(T&& value) : Base(std::move(value)) { +} + +template +StatusOr::StatusOr(Status&& status) : Base(std::move(status)) { +} + +template +StatusOr& StatusOr::operator=(Status&& status) { + this->Assign(std::move(status)); + return *this; +} + +template +template +inline StatusOr::StatusOr(const StatusOr& other) + : Base(static_cast::Base&>(other)) { +} + +template +template +inline StatusOr& StatusOr::operator=(const StatusOr& other) { + if (other.ok()) + this->Assign(other.ValueOrDie()); + else + this->Assign(other.status()); + return *this; +} + +template +template +inline StatusOr::StatusOr(StatusOr&& other) + : Base(static_cast::Base&&>(other)) { +} + +template +template +inline StatusOr& StatusOr::operator=(StatusOr&& other) { + if (other.ok()) { + this->Assign(std::move(other).ValueOrDie()); + } else { + this->Assign(std::move(other).status()); + } + return *this; +} + +template +const Status& StatusOr::status() const& { + return this->status_; +} +template +Status StatusOr::status() && { + return ok() ? Status::OK() : std::move(this->status_); +} + +template +const T& StatusOr::ValueOrDie() const& { + this->EnsureOk(); + return this->data_; +} + +template +T& StatusOr::ValueOrDie() & { + this->EnsureOk(); + return this->data_; +} + +template +const T&& StatusOr::ValueOrDie() const&& { + this->EnsureOk(); + return std::move(this->data_); +} + +template +T&& StatusOr::ValueOrDie() && { + this->EnsureOk(); + return std::move(this->data_); +} + +template +void StatusOr::IgnoreError() const { + // no-op +} + +} // namespace util +} // namespace firestore +} // namespace firebase + +#endif // FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_UTIL_STATUSOR_H_ diff --git a/Firestore/core/src/firebase/firestore/util/statusor_internals.h b/Firestore/core/src/firebase/firestore/util/statusor_internals.h new file mode 100644 index 0000000..d6c8de1 --- /dev/null +++ b/Firestore/core/src/firebase/firestore/util/statusor_internals.h @@ -0,0 +1,258 @@ +/* + * Copyright 2017, 2018 Google + * + * 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 + * + * http://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 FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_UTIL_STATUSOR_INTERNALS_H_ +#define FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_UTIL_STATUSOR_INTERNALS_H_ + +#include + +#include "Firestore/core/src/firebase/firestore/util/status.h" +#include "absl/base/attributes.h" + +namespace firebase { +namespace firestore { +namespace util { +namespace internal_statusor { + +class Helper { + public: + // Move type-agnostic error handling to the .cc. + static void HandleInvalidStatusCtorArg(Status*); + ABSL_ATTRIBUTE_NORETURN static void Crash(const Status& status); +}; + +// Construct an instance of T in `p` through placement new, passing Args... to +// the constructor. +// This abstraction is here mostly for the gcc performance fix. +template +void PlacementNew(void* p, Args&&... args) { +#if defined(__GNUC__) && !defined(__clang__) + // Teach gcc that 'p' cannot be null, fixing code size issues. + if (p == nullptr) __builtin_unreachable(); +#endif + new (p) T(std::forward(args)...); +} + +// Helper base class to hold the data and all operations. +// We move all this to a base class to allow mixing with the appropriate +// TraitsBase specialization. +template +class StatusOrData { + template + friend class StatusOrData; + + public: + StatusOrData() = delete; + + StatusOrData(const StatusOrData& other) { + if (other.ok()) { + MakeValue(other.data_); + MakeStatus(); + } else { + MakeStatus(other.status_); + } + } + + StatusOrData(StatusOrData&& other) noexcept { + if (other.ok()) { + MakeValue(std::move(other.data_)); + MakeStatus(); + } else { + MakeStatus(std::move(other.status_)); + } + } + + template + StatusOrData(const StatusOrData& other) { + if (other.ok()) { + MakeValue(other.data_); + MakeStatus(); + } else { + MakeStatus(other.status_); + } + } + + template + StatusOrData(StatusOrData&& other) { + if (other.ok()) { + MakeValue(std::move(other.data_)); + MakeStatus(); + } else { + MakeStatus(std::move(other.status_)); + } + } + + explicit StatusOrData(const T& value) : data_(value) { + MakeStatus(); + } + explicit StatusOrData(T&& value) : data_(std::move(value)) { + MakeStatus(); + } + + explicit StatusOrData(const Status& status) : status_(status) { + EnsureNotOk(); + } + explicit StatusOrData(Status&& status) : status_(std::move(status)) { + EnsureNotOk(); + } + + StatusOrData& operator=(const StatusOrData& other) { + if (this == &other) return *this; + if (other.ok()) + Assign(other.data_); + else + Assign(other.status_); + return *this; + } + + StatusOrData& operator=(StatusOrData&& other) { + if (this == &other) return *this; + if (other.ok()) + Assign(std::move(other.data_)); + else + Assign(std::move(other.status_)); + return *this; + } + + ~StatusOrData() { + if (ok()) { + status_.~Status(); + data_.~T(); + } else { + status_.~Status(); + } + } + + void Assign(const T& value) { + if (ok()) { + data_.~T(); + MakeValue(value); + } else { + MakeValue(value); + status_ = Status::OK(); + } + } + + void Assign(T&& value) { + if (ok()) { + data_.~T(); + MakeValue(std::move(value)); + } else { + MakeValue(std::move(value)); + status_ = Status::OK(); + } + } + + void Assign(const Status& status) { + Clear(); + status_ = status; + EnsureNotOk(); + } + + void Assign(Status&& status) { + Clear(); + status_ = std::move(status); + EnsureNotOk(); + } + + bool ok() const { + return status_.ok(); + } + + protected: + // status_ will always be active after the constructor. + // We make it a union to be able to initialize exactly how we need without + // waste. + // Eg. in the copy constructor we use the default constructor of Status in + // the ok() path to avoid an extra Ref call. + union { + Status status_; + }; + + // data_ is active iff status_.ok()==true + struct Dummy {}; + union { + // When T is const, we need some non-const object we can cast to void* for + // the placement new. dummy_ is that object. + Dummy dummy_; + T data_; + }; + + void Clear() { + if (ok()) data_.~T(); + } + + void EnsureOk() const { + if (!ok()) Helper::Crash(status_); + } + + void EnsureNotOk() { + if (ok()) Helper::HandleInvalidStatusCtorArg(&status_); + } + + // Construct the value (ie. data_) through placement new with the passed + // argument. + template + void MakeValue(Arg&& arg) { + internal_statusor::PlacementNew(&dummy_, std::forward(arg)); + } + + // Construct the status (ie. status_) through placement new with the passed + // argument. + template + void MakeStatus(Args&&... args) { + internal_statusor::PlacementNew(&status_, + std::forward(args)...); + } +}; + +// Helper base class to allow implicitly deleted constructors and assignment +// operations in StatusOr. +// TraitsBase will explicitly delete what it can't support and StatusOr will +// inherit that behavior implicitly. +template +struct TraitsBase { + TraitsBase() = default; + TraitsBase(const TraitsBase&) = default; + TraitsBase(TraitsBase&&) = default; + TraitsBase& operator=(const TraitsBase&) = default; + TraitsBase& operator=(TraitsBase&&) = default; +}; + +template <> +struct TraitsBase { + TraitsBase() = default; + TraitsBase(const TraitsBase&) = delete; + TraitsBase(TraitsBase&&) = default; + TraitsBase& operator=(const TraitsBase&) = delete; + TraitsBase& operator=(TraitsBase&&) = default; +}; + +template <> +struct TraitsBase { + TraitsBase() = default; + TraitsBase(const TraitsBase&) = delete; + TraitsBase(TraitsBase&&) = delete; + TraitsBase& operator=(const TraitsBase&) = delete; + TraitsBase& operator=(TraitsBase&&) = delete; +}; + +} // namespace internal_statusor +} // namespace util +} // namespace firestore +} // namespace firebase + +#endif // FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_UTIL_STATUSOR_INTERNALS_H_ -- cgit v1.2.3