text: /*    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 <boost/config.hpp>
  #include <iosfwd>
  #include <string>
  
  #include "mongo/base/error_codes.h"
  #include "mongo/platform/atomic_word.h"
  
  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. Optionally, a Status may also have an error location number, which
       * should be a unique, grep-able point in the code base (including assert numbers).
       *
       * 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();
       *   }
       *
       * TODO: expand base/error_codes.h to capture common errors in current code
       * TODO: generate base/error_codes.h out of a description file
       * TODO: check 'location' duplicates against assert numbers
       */
      class Status {
      public:
          // Short-hand for returning an OK status.
          static inline Status OK();
  
          /**
           * Builds an error status given the error code, a textual description of what
           * caused the error, and a unique position in the where the error occurred
           * (similar to an assert number)
           */
          Status(ErrorCodes::Error code, std::string reason, int location = 0);
  
          inline Status(const Status& other);
          inline Status& operator=(const Status& other);
  
          inline Status(Status&& other) BOOST_NOEXCEPT;
          inline Status& operator=(Status&& other) BOOST_NOEXCEPT;
  
          inline ~Status();
  
          /**
           * Returns true if 'other's error code and location are equal/different to this
           * instance's. Otherwise returns false.
           */
          bool compare(const Status& other) const;
          bool operator==(const Status& other) const;
          bool operator!=(const Status& other) const;
  
          /**
           * Returns true if 'other's error code is equal/different to this instance's.
           * Otherwise returns false.
           */
          bool compareCode(const ErrorCodes::Error other) const;
          bool operator==(const ErrorCodes::Error other) const;
          bool operator!=(const ErrorCodes::Error other) const;
  
          //
          // accessors
          //
  
          inline bool isOK() const;
  
          inline ErrorCodes::Error code() const;
  
          inline std::string codeString() const;
  
          inline std::string reason() const;
  
          inline int location() const;
  
          std::string toString() const;
  
          //
          // 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
              const int location;            // unique location of the triggering line in the code
  
              static ErrorInfo* create(ErrorCodes::Error code, std::string reason, int location);
  
              ErrorInfo(ErrorCodes::Error code, std::string reason, int location);
          };
  
          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);
  
      //
      // Convenience method for unittest code. Please use accessors otherwise.
      //
  
      std::ostream& operator<<(std::ostream& os, const Status& status);
      std::ostream& operator<<(std::ostream& os, ErrorCodes::Error);
  
  }  // namespace mongo
  
  #include "mongo/base/status-inl.h"
  