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[Vicențiu Ciorbaru <vicentiu@xxxxxxxxxxx>]

Hi Sergei,

I was doing some work within sql_acl.cc, having to refactor a bit of logic
regarding USER_RESOURCES and SSL related stuff and I'm thinking of making
use of std::string instead of const char* to remove the need for checking
NULL pointers.

I noticed that we generally do not make any use of std::string within the
server code, apart from storage engines. The use cases are not performance
sensitive so any overhead caused by std::string I think is smaller than the
benefit of not having if (!NULL) statements everywhere.

I know that it is obviously based on the final result, but if it is a
definite no from the start, I'll implement things using regular C pointers.

Also, this is only for the new things I'm implementing, I'm not planning on
refactoring everything.

Sample code where we can avoid ifs:

    case SSL_TYPE_SPECIFIED:
      table->field[next_field]->store(STRING_WITH_LEN("SPECIFIED"),
                                      &my_charset_latin1);
      table->field[next_field+1]->store("", 0, &my_charset_latin1);
      table->field[next_field+2]->store("", 0, &my_charset_latin1);
      table->field[next_field+3]->store("", 0, &my_charset_latin1);
      if (lex->ssl_cipher)
        table->field[next_field+1]->store(lex->ssl_cipher,
                                strlen(lex->ssl_cipher),
system_charset_info);
      if (lex->x509_issuer)
        table->field[next_field+2]->store(lex->x509_issuer,
                                strlen(lex->x509_issuer),
system_charset_info);
      if (lex->x509_subject)
        table->field[next_field+3]->store(lex->x509_subject,
                                strlen(lex->x509_subject),
system_charset_info);

This just becomes:
    case SSL_TYPE_SPECIFIED:
      table->field[next_field]->store(STRING_WITH_LEN("SPECIFIED"),
                                      &my_charset_latin1);
      table->field[next_field+1]->store(ssl_cipher.c_str(),
ssl_cipher.size(), &my_charset_latin1);
      table->field[next_field+2]->store(x509_issuer.c_str(),
x509_issuer.size(), &my_charset_latin1);
      table->field[next_field+3]->store(x509_subject.c_str(),
x509_subject.size(), &my_charset_latin1);

Thoughts?

Regards,
Vicentiu