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/* Copyright 2012 10gen Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects
* for all of the code used other than as permitted herein. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you do not
* wish to do so, delete this exception statement from your version. If you
* delete this exception statement from all source files in the program,
* then also delete it in the license file.
*/
#pragma once
#include <iosfwd>
#include <string>
#include "mongo/base/error_codes.h"
#include "mongo/platform/atomic_word.h"
#include "mongo/platform/compiler.h"
namespace mongoutils {
namespace str {
class stream;
} // namespace str
} // namespace mongoutils
namespace mongo {
/**
* Status represents an error state or the absence thereof.
*
* A Status uses the standardized error codes -- from file 'error_codes.h' -- to
* determine an error's cause. It further clarifies the error with a textual
* description.
*
* Example usage:
*
* Status sumAB(int a, int b, int* c) {
* if (overflowIfSum(a,b)) {
* return Status(ErrorCodes::ERROR_OVERFLOW, "overflow in sumAB", 16494);
* }
*
* *c = a+b;
* return Status::OK();
* }
*/
class MONGO_WARN_UNUSED_RESULT_CLASS Status {
public:
// Short-hand for returning an OK status.
static inline Status OK();
/**
* Builds an error status given the error code and a textual description of what
* caused the error.
*
* For OK Statuses prefer using Status::OK(). If code is OK, the remaining arguments are
* ignored.
*/
MONGO_COMPILER_COLD_FUNCTION Status(ErrorCodes::Error code, std::string reason);
MONGO_COMPILER_COLD_FUNCTION Status(ErrorCodes::Error code, const char* reason);
MONGO_COMPILER_COLD_FUNCTION Status(ErrorCodes::Error code, StringData reason);
MONGO_COMPILER_COLD_FUNCTION Status(ErrorCodes::Error code,
const mongoutils::str::stream& reason);
inline Status(const Status& other);
inline Status& operator=(const Status& other);
inline Status(Status&& other) noexcept;
inline Status& operator=(Status&& other) noexcept;
inline ~Status();
/**
* Only compares codes. Ignores reason strings.
*/
bool operator==(const Status& other) const {
return code() == other.code();
}
bool operator!=(const Status& other) const {
return !(*this == other);
}
/**
* Compares this Status's code with an error code.
*/
bool operator==(const ErrorCodes::Error other) const {
return code() == other;
}
bool operator!=(const ErrorCodes::Error other) const {
return !(*this == other);
}
//
// accessors
//
inline bool isOK() const;
inline ErrorCodes::Error code() const;
inline std::string codeString() const;
/**
* Returns the reason string or the empty string if isOK().
*/
const std::string& reason() const {
if (_error)
return _error->reason;
static const std::string empty;
return empty;
}
std::string toString() const;
/**
* Call this method to indicate that it is your intention to ignore a returned status. Ignoring
* is only possible if the value being ignored is an xvalue -- it is not appropriate to create a
* status variable and then ignore it.
*/
inline void ignore() && noexcept {}
inline void ignore() const& noexcept = delete;
/**
* This method is a transitional tool, to facilitate transition to compile-time enforced status
* checking.
*
* NOTE: DO NOT ADD NEW CALLS TO THIS METHOD. This method serves the same purpose as
* `.ignore()`; however, it indicates a situation where the code that presently ignores a status
* code has not been audited for correctness. This method will be removed at some point. If you
* encounter a compiler error from ignoring the result of a status-returning function be sure to
* check the return value, or deliberately ignore the return value.
*/
inline void transitional_ignore() && noexcept {};
inline void transitional_ignore() const& noexcept = delete;
//
// Below interface used for testing code only.
//
inline AtomicUInt32::WordType refCount() const;
private:
inline Status();
struct ErrorInfo {
AtomicUInt32 refs; // reference counter
const ErrorCodes::Error code; // error code
const std::string reason; // description of error cause
static ErrorInfo* create(ErrorCodes::Error code, std::string reason);
ErrorInfo(ErrorCodes::Error code, std::string reason);
};
ErrorInfo* _error;
/**
* Increment/Decrement the reference counter inside an ErrorInfo
*
* @param error ErrorInfo to be incremented
*/
static inline void ref(ErrorInfo* error);
static inline void unref(ErrorInfo* error);
};
inline bool operator==(const ErrorCodes::Error lhs, const Status& rhs);
inline bool operator!=(const ErrorCodes::Error lhs, const Status& rhs);
std::ostream& operator<<(std::ostream& os, const Status& status);
} // namespace mongo
#include "mongo/base/status-inl.h"
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