//#include "Exception.mpp"
///////////////////////////////hh.p////////////////////////////////////////
-/** \defgroup exception System exceptions
+/** \defgroup exception Exception classes
- 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:
+ All exceptions in senf are derived from senf::Exception. This class adds the possibility to
+ extend the exception description while it is processed:
\code
try {
- something.open(path);
- // ...
- }
- catch (senf::ErrnoException<ENOFILE> & e) {
- // Create new file
+
+ // Some code which might raise an arbitrary senf exception
+
}
- catch (senf::SystemException & e) {
- // Catch all other system exceptions
- std::cerr << "Error accessing '" << path << "': " << e.what() << std::endl;
+ catch (senf::Exception & e) {
+ e << "\handling user " << user;
+ throw;
}
\endcode
- This exception is normally thrown using the senf::throwErrno() helper:
+ This will add the user information to any senf exception thrown. The Exception is however not a
+ stream. If you need to do more extensive formating, either use an intermediate string-stream or
+ use <a href="http://www.boost.org/libs/format/doc/format.html">Boost.Format</a>:
\code
- if ((fd = ::open(path.c_str(), O_RDWR)) < 0)
- senf::throwErrno("::open()");
+ try {
+ // ...
+ }
+ catch (senf::Exception & e) {
+ e << boost::format("\ncall id 0x%04x@%s") % id % address;
+ }
\endcode
- The senf::throwErrno() helper will throw the correct exception class based on some \c errno
- value.
- */
+ senf::SystemException is thrown for all operating system errors (failures which result in the
+ operating system setting the errno value). It is also derived from senf::Exception and can
+ therefore be extended as well.
-namespace senf {
+ Defining your own exception classes derived from senf::Exception is very simple:
- /** \brief Exception handling standard UNIX errors (errno)
+ \code
+ struct FooException : public senf::Exception
+ { FooException() : senf::Exception("Foo hit the fan") {} };
+ \endcode
+ */
- This exception is thrown to signal generic \c errno failures.
+namespace senf {
- This exception cannot be thrown directly. Instead the derived class ErrnoException should be
- thrown via one of the senf::throwErrno helpers.
+ /** \brief Generic exception base-class
- The error message associated with the SystemException may be extended arbitrarily by using
- the exception like a stream:
- \code
- try {
- // This throw would normally be within some function called from here.
- senf::throwErrno("::open()");
-
- // Or you may want to use a more descriptive argument string:
- senf::throwErrno("::open(\"" + filename + "\")");
-
- // Or even use boost::format here
- senf::throwErrno((boost::format("::open(\"%s\")") % filename).str());
- }
- catch (SystemException & e) {
- // You can add further error information later by catching and re-throwing the exception
- e << " [while operating on user '" << user << "']";
- throw;
- }
- \endcode
+ Exception is a generic exception base-class which allows the exception to be later extended
+ by catching and re-throwing it (See example in \ref exception).
- \see ErrnoException
\ingroup exception
- */
- class SystemException : public std::exception, public std::stringstream
+ */
+ class Exception
+ : public std::exception
{
public:
- virtual char const * what() const throw(); ///< Return verbose error description
+ ///////////////////////////////////////////////////////////////////////////
+ ///\name Structors and default members
+ ///@{
- int errorNumber() const; ///< Error code (\c errno number)
- char const * description() const; ///< Error description (strerror() value)
+ virtual ~Exception() throw();
- 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 errorNumber() is one of \a c0 ... \a c9
+ ///@}
+ ///////////////////////////////////////////////////////////////////////////
- virtual ~SystemException() throw();
+ virtual char const * what() const throw();
+
+ template <class Arg>
+ Exception & operator<<(Arg const & arg); ///< Extend exception description
+ /**< Adds \a arg converted to string to the end of the
+ exception description string. This operator allows to
+ use Exception instances like streams. The conversion is
+ performed using <code>boost::lexical_cast</code> and is
+ therefor identical to a streaming operation.
+ \see \ref exception */
protected:
- SystemException(std::string const & where, int code);
- SystemException(SystemException const & other);
+ Exception(std::string const & description = ""); ///< Initialize exception with string
+ /**< \a description is the initial error description
+ string. This should probably be a string constant
+ describing the exception for most derived
+ exceptions. */
private:
- int const code_; // This must be const to make the derived ErrnoException
- // class a valid derived class.
- mutable std::string buffer_;
-
- friend void throwErrno(std::string const &, int);
+ std::string message_;
};
- /** \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.
+ /** \brief Exception handling standard UNIX errors (errno)
+
+ This exception is thrown to signal generic \c errno failures. Normally the \c errno value is
+ automatically taken from the \c errno variable but it may also be specified 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
+ // Standard usage: Take \c errno from environment
+ throw senf::SystemException("::open()")
+ << " while opening configuration file: " << filename;
- \see SystemException
+ // You may however explicitly specify the errno value
+ throw senf::SystemException("::open()", ENOFILE)
+
+ // Or leave the location information empty
+ throw senf::SystemException(ENOFILE);
+ throw senf::SystemException();
+ \endcode
\ingroup exception
*/
- template <int Code>
- class ErrnoException : public SystemException
+ class SystemException : public Exception
{
public:
- static int const fixed_code = Code;
+ ///////////////////////////////////////////////////////////////////////////
+ ///\name Structors and default members
+ ///@{
- explicit ErrnoException(std::string const & where);
- ///< ErrnoException with error location information
-
- ErrnoException(ErrnoException const & other);
- };
+ explicit SystemException(std::string const & where = "");
+ explicit SystemException(int code);
+ SystemException(std::string const & where, int code);
-
- /** \brief Throw ErrnoException based on current \c errno value
- \ingroup exception
- */
- void throwErrno();
+ virtual ~SystemException() throw();
- /** \brief Throw ErrnoException based on current \c errno value (with location info)
- \ingroup exception
- */
- void throwErrno(std::string const & where);
+ ///@}
+ ///////////////////////////////////////////////////////////////////////////
- /** \brief Throw ErrnoException based on given \c errno value
- \ingroup exception
- */
- void throwErrno(int code);
+ int errorNumber() const; ///< Error code (\c errno number)
+ char const * description() const; ///< Error description (\c strerror() value)
- /** \brief Throw ErrnoException based on given \c errno value (with location info)
- \ingroup exception
- */
- void throwErrno(std::string const & where, int code);
+ 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 errorNumber() is one of \a c0 ... \a c9
+
+
+
+ private:
+ void init(std::string const & where, int code);
+
+ int code_;
+ };
}
projects / senf.git / blobdiff