X-Git-Url: http://g0dil.de/git?a=blobdiff_plain;f=Utils%2FException.hh;h=b19c2db85d6004da3071040bfef194e83b39a75f;hb=85dd621b12b8c974b132e6af0818f64a029b081d;hp=e673ab57741f866e4237683bb73a198a470dac5e;hpb=47368f306a577d1e46df69a7f729bd3893cbe5e7;p=senf.git diff --git a/Utils/Exception.hh b/Utils/Exception.hh index e673ab5..b19c2db 100644 --- a/Utils/Exception.hh +++ b/Utils/Exception.hh @@ -29,48 +29,146 @@ // Custom includes #include #include +#include +#include //#include "Exception.mpp" ///////////////////////////////hh.p//////////////////////////////////////// +/** \defgroup exception System exceptions + + The senf::SystemException class and it's derived class template senf::ErrnoException are used to + signal generic system failures based on \c errno codes. + + senf::SystemException is a generic \c errno based exception which carries an error number and + origin information. senf::ErrnoException is a derived class specialized for a specific error + code. This simplifies managing error conditions: + + \code + try { + something.open(path); + // ... + } + catch (senf::ErrnoException & e) { + // Create new file + } + catch (senf::SystemException & e) { + // Catch all other system exceptions + std::cerr << "Error accessing '" << path << "': " << e.what() << std::endl; + } + \endcode + + This exception is normally thrown using the senf::throwErrno() helper: + + \code + if ((fd = ::open(path.c_str(), O_RDWR)) < 0) + senf::throwErrno("::open()"); + \endcode + + The senf::throwErrno() helper will throw the correct exception class based on some \c errno + value. + */ + namespace senf { /** \brief Exception handling standard UNIX errors (errno) - This exception is thrown to signal generic errno failures. - - \todo make where and err accessors and make the member vars private + This exception is thrown to signal generic \c errno failures. In addition to the \c errno + number (the code()), this class manages optional origin information. This parameter should + be provided to further describe, in what context the exception was created. - \idea Add a template class derived from SystemException which - takes the error number as a numeric argument. This allows - catching specific errno conditions: ErrnoException etc. + This exception should not be used directly. Instead the derived class ErrnoException should + be thrown via one of the senf::throwErrno() helpers. - \idea Add a generic error thrower which takes the origin - string and errno value as an argument and will throw a - corresponding template class instance. This would just be a - big switch statement containing all possible errno values, - probably created using some macro metaprogramming. + \see ErrnoException + \ingroup exception */ class SystemException : public std::exception { public: - explicit SystemException(int err); ///< SystemException without error lokus info - /**< \param[in] err error number (the errno value) */ - SystemException(char const * where, int err); ///< SystemException with error lokus info + SystemException(); ///< SystemException without error location infor + /**< The error code is taken from the current value of the + global \c errno variable */ + + explicit SystemException(int code); ///< SystemException without error location info + /**< \param[in] code error number (the \c errno value) */ + + explicit SystemException(char const * where); ///< SystemException with error location info + /**< The error code is taken from the current value of the + global \c errno variable + \param[in] where description of error origin */ + + SystemException(char const * where, int code); ///< SystemException with error location info /**< \param[in] where description of error origin - \param[in] err error number (the errno value) */ + \param[in] code error number (the \c errno value) */ virtual char const * what() const throw(); ///< Return verbose error description - char const * where; ///< Error origin - int err; ///< Error number + char const * where() const; ///< Error origin + int code() const; ///< Error code (\c errno number) + char const * description() const; ///< Error description (strerror() value) + + bool anyOf(int c0, int c1=0, int c2=0, int c3=0, int c4=0, int c5=0, + int c6=0, int c7=0, int c8=0, int c9=0); + ///< \c true, if code() is one of \a c0 ... \a c9 virtual ~SystemException() throw(); + private: void init(); + + char const * const where_; + int const code_; // This must be const to make the derived ErrnoException + // class a valid derived class. std::string buffer_; }; + /** \brief Error specific system exception + + This template restricts the generic SystemException to a specific, compile-time constant + error number \p Code. This allows a specific \c errno number to be cached explicitly. + + This exception is normally thrown via one of the senf::throwErrno() helpers. These helpers + take the numeric \c errno value (either from the \c errno variable or from their + argument) and will throw the corresponding ErrnoException: + \code + if ((fd = ::open(filename, O_RDWR)) < 0) + senf::throwErrno("open()"); + \endcode + \ingroup exception + */ + template + class ErrnoException : public SystemException + { + public: + static int const fixed_code = Code; + + ErrnoException(); ///< ErrnoException without error location information + explicit ErrnoException(char const * where); + ///< ErrnoException with error location information + }; + + + /** \brief Throw ErrnoException based on current \c errno value + \ingroup exception + */ + void throwErrno(); + + /** \brief Throw ErrnoException based on current \c errno value (with location info) + \ingroup exception + */ + void throwErrno(char const * where); + + /** \brief Throw ErrnoException based on given \c errno value + \ingroup exception + */ + void throwErrno(int code); + + /** \brief Throw ErrnoException based on given \c errno value (with location info) + \ingroup exception + */ + void throwErrno(char const * where, int code); + enum NoThrow_t { nothrow }; } @@ -78,7 +176,7 @@ namespace senf { ///////////////////////////////hh.e//////////////////////////////////////// #include "Exception.cci" //#include "Exception.ct" -//#include "Exception.cti" +#include "Exception.cti" #endif