Re: [bug-myserver] [PROPOSAL] Exception management scheme

[Daniele Perrone]

Hi All,

I've just a question, what about the performance? It's important to
manage exceptions in the best way, but we have to keep in mind that
performance are important in a web server:)

Cheers,
Daniele

On Sun, Mar 28, 2010 at 12:13 AM, Giuseppe Scrivano <address@hidden> wrote:
> Hello Lisa,
>
> As we already discussed privately, it looks like a good proposal and I
> agree on everything.
>
> Does anyone have comments?
>
> Cheers,
> Giuseppe
>
>
>
> Lisa Vitolo <address@hidden> writes:
>
>> Hi,
>> I've just taken the task #8646 ("Define an exceptions set") and I want to 
>> propose and eventually discuss a generic scheme.
>>
>> There will be an abstract super class (an interface), let's call it 
>> MyServerException, with some virtual methods
>> definitions. This class will be extended by the exception classes, which 
>> will represent the different errno values.
>> I was thinking also of making some categories, abstract classes in the 
>> middle between the superclass and the single
>> exceptions. They can be useful if a developer wants to catch a whole bunch 
>> of exceptions regarding the same "area". I think
>> of: MemoryExceptions (errors like ENOMEM, ENOSPC), SocketExceptions (almost 
>> every error regarding the socket and connection
>> management) and FileExceptions.
>> Little note: some exceptions will need to extend bad_alloc or other 
>> exceptions from the std library to avoid conflicts (for
>> example during a dynamic allocation when bad_alloc can be thrown).
>>
>> Coming back to the exception, the structure should look like
>> class Exception : public Category (or MyServerException)
>> {
>>   int priority; /* this value describes the level of priority of the 
>> exception. It cannot be modified and can be useful to
>> the developer for deciding the next action. */
>>
>>   public:
>>     Exception()
>>     {
>>       sets right priority
>>     }
>>     int getPriority()
>>     {
>>        return priority;
>>     }
>>    virtual const char* what() const throw() /* this definition is the 
>> classic one! */
>>    {
>>       return "Error message";
>>    }
>>    char **getBacktrace()
>>    {
>>      return the backtrace obtained from the glib backtrace_symbols function. 
>> (http://www.gnu.org/software/libtool/manual/
>> libc/Backtraces.html)
>>    }
>> };
>>
>> Eventually, we can wrap this entire system in a macro or function 
>> CHECK_ERROR that takes the return value of a function and
>> throws the appropriate exception if necessary.
>>
>> Usage example:
>> try
>> {
>>    CHECK_ERROR(bind(...));
>> } catch ...
>>
>> Good night,
>> Lisa
>>
>> --
>> "The truth can be out there, but lies are inside our heads" -- Terry 
>> Pratchett
>
>
>