Hi everyone, We've been using the STL quite liberally with much of the new Drizzle code, but we've been doing little to no exception handling around it. Right now most calls to std::string/STL methods that could modify/allocate underlying data structures could fail, and without a catch, this is the equivalent to putting an assert() after every malloc call ensuring it succeeded. While this may make Stewart happy since we are essentially taking the crash-only software approach, I worry we're not catching edge cases and cleaning up properly. Also, not all failures should lead to the server halting.
This extends beyond simple memory allocation as well, for example std::out_of_range can be thrown if passing invalid indexes into some STL container methods as well. Beyond handling exceptions throw by string/STL, there have also be discussions about Drizzle's use of exceptions in general. For portability reasons, you can't reliably throw custom C++ exceptions across shared object boundaries because RTTI (run time type information) will not always be correct. We either need to decide to not allow exceptions to cross shared library boundaries (thinking plugins mainly) or not worry about supporting the platforms/compilers that can't handle it (which first requires identifying them). My suggestion would be to: * Not allow custom exceptions. There may be a possible exception for some plugins which require them if they are based on other libraries that use them, but this should be discouraged. * Never allow exceptions to propagate across module boundaries. * Catch string/STL exceptions as close as possible to the source and translate those into return codes. This allows calling methods to do the correct thing, whether it be abort a query, abort a session, or halt the entire server. What do other folks think? -Eric _______________________________________________ Mailing list: https://launchpad.net/~drizzle-discuss Post to : [email protected] Unsubscribe : https://launchpad.net/~drizzle-discuss More help : https://help.launchpad.net/ListHelp
