[C++][Error Code]如何定义Error Code框架

对于不同的项目而言，error code返回机制是不一样的，但是能够很好的管理好不同模块间的Error Code并不是一件简单的事情，下面有一种比较简便的方法如下：

/**************************************************************************************************/
/*!
    \file CommonErrors.h

    \attention
        (c) Jacky Dai 2011~2016
        All Rights Reserved.
*/

/**************************************************************************************************/

#ifndef XX_COMMON_ERRORS_H
#define XX_COMMON_ERRORS_H

/*** Include Files ********************************************************************************/

/*** Defines/Macros/Constants/Typedefs ************************************************************/

namespace XXSpace
{
//basic mask code
const unsigned int COMPONENT_MASK       = 0x8000;

//component code
const unsigned int COMPONENT_LOGIN            = 0x0001;
const unsigned int COMPONENT_DATAMANAGER      = 0x0002;

//
//0x0000XXXX:XXXX means component code
//0xXXXX0000:XXXX means error code of component

//Define some marcos/functions here
#define SYSTEM_ERROR_FLAG (0x4000)
#define SYSTEM_ERROR(code) ((code | SYSTEM_ERROR_FLAG) << 16)
#define ERROR_IS_SYSTEM_ERROR(err) (((err >> 16) & SYSTEM_ERROR_FLAG) != 0)

#define COMPONENT_ERROR(component, code) ((code << 16) | (component & ~(COMPONENT_MASK)))
#define CODE_FROM_ERROR(err) (static_cast<short>(err >> 16))

//All of the error code is here
typedef enum
{
                                                                                 //   Hex        | Decimal       | Descriptio
    //Basic error
    ERR_OK                                 = 0x00000000,                         //<< 0x00000000 |  0            | No error.
    ERR_SYSTEM                             = SYSTEM_ERROR(1),                    //<< 0x00010000 | 65536         | General system error.
    ERR_TIMEOUT                            = SYSTEM_ERROR(2),                    //<< 0x00020000 | 131072        | Time out.
    
    //login component
    LOGIN_ERROR_UNKNOWN_ERROR              = COMPONENT_ERROR(COMPONENT_LOGIN, 1),     //<< 0x00010001 |65537    | Unrecognized error.
    LOGIN_ERROR_UNKNOWN_USER_NAME          = COMPONENT_ERROR(COMPONENT_LOGIN, 2),     //<< 0x00020001 |131073   | Unrecognized user name, it is case sensitive.
    
    //data manager component
    DATAMANAGER_ERROR_UNKNOWN_ERROR        = COMPONENT_ERROR(COMPONENT_DATAMANAGER, 1), //<< 0x00010002 |65538   | Unrecognized error.
    DATAMANAGER_ERROR_MISSING_CONNECTION   = COMPONENT_ERROR(COMPONENT_DATAMANAGER, 2)  //<< 0x00020002 |131074   | Connection missed.
} XXCommonError;


/**************************************************************************************************/
/*!
    \class ErrorHelper

    Class with commands for translating error codes to useful strings.

*/
/**************************************************************************************************/
class ErrorHelper
{
public:
    static const char* getErrorName(XXCommonError error);
    static const char* getErrorDescription(XXCommonError error);
};

} // XXSpace

#endif //XX_COMMON_ERRORS_H

/**************************************************************************************************/
/*!
    \file CommonErrors.cpp

    \attention
        (c) Jacky Dai 2011~2016
        All Rights Reserved.
*/

/**************************************************************************************************/

/*** Include Files ********************************************************************************/
#include "CommonErrors.h"

/*** Defines/Macros/Constants/Typedefs ************************************************************/

namespace XXSpace
{
/*** Public Methods ******************************************************************************/
const char* ErrorHelper::getErrorName(XXCommonError error)
{
    const char* result = "UKNOWN";

    switch (error)
    {
        case ERR_OK: result = "ERR_OK"; break;
        case ERR_SYSTEM: result = "ERR_SYSTEM"; break;
        case ERR_TIMEOUT: result = "ERR_TIMEOUT"; break;
        case LOGIN_ERROR_UNKNOWN_ERROR: result = "LOGIN_ERROR_UNKNOWN_ERROR"; break;
        case LOGIN_ERROR_UNKNOWN_USER_NAME: result = "LOGIN_ERROR_UNKNOWN_USER_NAME"; break;
        case DATAMANAGER_ERROR_UNKNOWN_ERROR: result = "DATAMANAGER_ERROR_UNKNOWN_ERROR"; break;
        case DATAMANAGER_ERROR_MISSING_CONNECTION: result = "DATAMANAGER_ERROR_MISSING_CONNECTION"; break;
        default: break;
    }

    return result;
}

const char* ErrorHelper::getErrorDescription(XXCommonError error)
{
    const char *result = "UKNOWN";

    switch (error)
    {
        case ERR_OK: result = "No error."; break;
        case ERR_SYSTEM: result = "General system error."; break;
        case ERR_TIMEOUT: result = "Time out."; break;
        case LOGIN_ERROR_UNKNOWN_ERROR: result = "Unrecognized error."; break;
        case LOGIN_ERROR_UNKNOWN_USER_NAME: result = "Unrecognized user name, it is case sensitive."; break;
        case DATAMANAGER_ERROR_UNKNOWN_ERROR: result = "Unrecognized error."; break;
        case DATAMANAGER_ERROR_MISSING_CONNECTION: result = "Connection missed."; break;
        default: break;
    }

    return result;
}

} // XXSpace

One sample for this architecture, it's easy to control, isn't it? Any problems, please let me know.

#include <Windows.h>
#include "CommonErrors.h"
#include <iostream>
using namespace std;


/**************************************************************************************************/
/*!
    \class XXStub

    Stub class for the XXXX.
*/
/**************************************************************************************************/
class Login{};
class LoginStub : public Login
{
public:
    typedef enum
    {
        ERR_OK                        = XXSpace::ERR_OK,
        ERR_SYSTEM                    = XXSpace::ERR_SYSTEM,
        ERR_TIMEOUT                   = XXSpace::ERR_TIMEOUT,
        LOGIN_ERROR_UNKNOWN_ERROR     = XXSpace::LOGIN_ERROR_UNKNOWN_ERROR,
        LOGIN_ERROR_UNKNOWN_USER_NAME = XXSpace::LOGIN_ERROR_UNKNOWN_USER_NAME
    } Errors;
    
    Errors DoLogin(const char* userName, const char* password);
    const char* GetLoginStubErrorName(Errors error);
    const char* getErrorDescription(Errors error);
};

LoginStub::Errors LoginStub::DoLogin(const char* userName, const char* password)
{
    if( userName==NULL
     || password==NULL )
    {
        return LOGIN_ERROR_UNKNOWN_USER_NAME;
    }        
    
    return ERR_OK;
}

const char* LoginStub::GetLoginStubErrorName(Errors error)
{
    return XXSpace::ErrorHelper::getErrorName(static_cast<XXSpace::XXCommonError>(error));
}

const char* LoginStub::getErrorDescription(Errors error)
{
    return XXSpace::ErrorHelper::getErrorDescription(static_cast<XXSpace::XXCommonError>(error));
}

class DataManager{};
class DataManagerStub : public DataManager
{
public:
    typedef enum
    {
        ERR_OK                               = XXSpace::ERR_OK,
        ERR_SYSTEM                           = XXSpace::ERR_SYSTEM,
        ERR_TIMEOUT                          = XXSpace::ERR_TIMEOUT,
        DATAMANAGER_ERROR_UNKNOWN_ERROR      = XXSpace::DATAMANAGER_ERROR_UNKNOWN_ERROR,
        DATAMANAGER_ERROR_MISSING_CONNECTION = XXSpace::DATAMANAGER_ERROR_MISSING_CONNECTION
    } Errors;

    Errors Test();
    const char* GetDataManagerStubErrorName(Errors error);
    const char* getErrorDescription(Errors error);
};

DataManagerStub::Errors DataManagerStub::Test()
{
    return DATAMANAGER_ERROR_UNKNOWN_ERROR;
}

const char* DataManagerStub::GetDataManagerStubErrorName(Errors error)
{
    return XXSpace::ErrorHelper::getErrorName(static_cast<XXSpace::XXCommonError>(error));
}

const char* DataManagerStub::getErrorDescription(Errors error)
{
    return XXSpace::ErrorHelper::getErrorDescription(static_cast<XXSpace::XXCommonError>(error));
}


//////////////////////////////////////////////////////////////////////////
void main()
{
    LoginStub cLogin;
    LoginStub::Errors loginError = cLogin.DoLogin(NULL, NULL);
    cout << hex << loginError << " = ";
    cout << cLogin.GetLoginStubErrorName(loginError) << endl;
    cout << cLogin.getErrorDescription(loginError) << endl;

    DataManagerStub dm;
    DataManagerStub::Errors dmError = dm.Test();
    cout << hex << dmError << " = ";
    cout << dm.GetDataManagerStubErrorName(dmError) << endl; 
    cout << dm.getErrorDescription(dmError) << endl; 
}