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// status_with.h
/* Copyright 2013 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 "mongo/base/status.h"
namespace mongo {
/*
* StatusWith is used to return an error or a value
* this is designed to make exception code free cleaner by not needing as many out paramters
* example:
StatusWith<int> fib( int n ) {
if ( n < 0 ) return StatusWith<int>( ErrorCodes::BadValue, "paramter to fib has to be >= 0" );
if ( n <= 1 ) return StatusWith<int>( 1 );
StatusWith<int> a = fib( n - 1 );
StatusWith<int> b = fib( n - 2 );
if ( !a.isOK() ) return a;
if ( !b.isOK() ) return b;
return StatusWith<int>( a.getValue() + b.getValue() );
}
* Note: the value is copied in the current implementation, so should be small (int, int*)
* not a vector
*/
template<typename T>
class StatusWith {
public:
/**
* for the error case
*/
StatusWith( ErrorCodes::Error code, const std::string& reason, int location = 0 )
: _status( Status( code, reason, location ) ) {
}
/**
* for the error case
*/
explicit StatusWith( const Status& status )
: _status( status ) {
// verify(( !status.isOK() ); // TODO
}
/**
* for the OK case
*/
explicit StatusWith( const T& t )
: _status( Status::OK() ), _t( t ) {
}
const T& getValue() const { /* verify( isOK() ); */ return _t; } // TODO
const Status& getStatus() const { return _status;}
bool isOK() const { return _status.isOK(); }
string toString() const { return _status.toString(); }
private:
Status _status;
T _t;
};
}
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