X-Git-Url: http://g0dil.de/git?a=blobdiff_plain;f=senf%2FUtils%2FException.hh;fp=senf%2FUtils%2FException.hh;h=c6f32572797c72dfe7ee348a4b6cee148ff0a83a;hb=601d1f509f5bb24df167a4dd5a20da67a0af9af8;hp=0000000000000000000000000000000000000000;hpb=164fe477094d42463722584e527a02379ab5d985;p=senf.git diff --git a/senf/Utils/Exception.hh b/senf/Utils/Exception.hh new file mode 100644 index 0000000..c6f3257 --- /dev/null +++ b/senf/Utils/Exception.hh @@ -0,0 +1,335 @@ +// $Id$ +// +// Copyright (C) 2006 +// Fraunhofer Institute for Open Communication Systems (FOKUS) +// Competence Center NETwork research (NET), St. Augustin, GERMANY +// Stefan Bund +// +// This program is free software; you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation; either version 2 of the License, or +// (at your option) any later version. +// +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License +// along with this program; if not, write to the +// Free Software Foundation, Inc., +// 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + +/** \file + \brief Exception public header */ + +#ifndef HH_SENF_Utils_Exception_ +#define HH_SENF_Utils_Exception_ 1 + +// Custom includes +#include +#include +#include +#include +#include +#include +#include +#include + +//#include "Exception.mpp" +///////////////////////////////hh.p//////////////////////////////////////// + +/** \defgroup exception Exception classes + + All exceptions in %senf are derived from senf::Exception. This class adds the possibility to + extend the exception description while it is processed. The functionality is provided by a mixin + class senf::ExceptionMixin: + + \code + try { + + // Some code which might raise an arbitrary senf exception + + } + catch (senf::ExceptionMixin & e) { + e << "\handling user " << user; + throw; + } + \endcode + + 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 Boost.Format: + + \code + try { + // ... + } + catch (senf::ExceptionMixin & e) { + e << boost::format("\n" "call id 0x%04x@%s") % id % address; + } + \endcode + + 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. + + Defining your own exception classes derived from senf::Exception is very simple: + + \code + struct FooException : public senf::Exception + { FooException() : senf::Exception("Foo hit the fan") {} }; + \endcode + + If SENF is compiled in debug mode (SENF_DEBUG is defined), the exception message will + automatically include a stack backtrace. For this to work, you need to add the + -rdynamic option to all link commands. This feature depends on gcc and + the GNU-libc. + + To apply these features (extensibility, backtrace) to a non-senf exception, the non-senf + exception can be wrapped and re-thrown. + \code + void foo() { + try { + // ... code that might throw std::bad_cast or somelib::FooException + } + SENF_WRAP_EXC(std::bad_cast) + SENF_WRAP_EXC(somelib::FooException) + } + \endcode + The re-thrown exception can then be caught as std::bad_cast or as senf::ExceptionMixin + as needed. It is safe, to wrap an exception twice (the macro will detect this case). + \code + bar() { + try { + try { + foo(); + } + catch (senf::ExceptionMixin & ex) { + ex << "\n" "add this info"; + } + } + catch (std::bad_cast const & ex) { + std::cerr << ex.what() << std::endl; + } + \endcode + The final error output will include + \li a backtrace if compiled in debug mode + \li the original error message from the std::bad_cast exception + \li the additional error message "add this info" + + \todo Link against libcwd to add file-name/line-number information to the backtrace and remove + the dependency on -rdynamic + \todo Or better, use addr2line to obtain that information when showing the backtrace when + catched within Daemon (addr2line -fsiCe argv[0]) + \todo Add signal handlers for the bad signals which writes a backtrace to stderr and + terminates. This should probably write out a raw backtrace without de-mangling or + line-numbers since we don't want to mess with dynamic memory when the heap might be + corrupted ... Another handler for e.g. SIGUSR2 is nice to show a debug backtrace on demand + */ + +namespace senf { + + /** \brief Generic extensible exception mixin + + ExceptionMixin is a generic exception mixin which allows the exception to be later extended + by catching and re-throwing it (See example in \ref exception). + + \ingroup exception + */ + class ExceptionMixin + { + public: + std::string message() const; ///< get exception description + std::string backtrace() const; ///< Return backtrace (if available) + + void append(std::string text); ///< Extend exception description + /**< Adds \a text to the description text. */ + + protected: + explicit ExceptionMixin(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. */ + + std::string what_; + private: +#ifdef SENF_DEBUG + void addBacktrace(); + std::string::size_type excLen_; +#endif + }; + + /** \brief Extensible exception base-class + + This base-class is an exception which already includes the ExceptionMixin. All SENF + exceptions are derived from this class. Other user-exception may be defined by deriving from + this class too. + + \see \ref exception + + \ingroup exception + */ + class Exception + : public ExceptionMixin, public std::exception + { + public: + virtual ~Exception() throw(); + + virtual char const * what() const throw(); + ///< get exception description and backtrace if available + /**< get description of the exception (message()) and backtrace + information if SENF is compiled with \c SENF_DEBUG */ + + protected: + explicit Exception(std::string const & description = ""); + }; + + /** \brief Wrapper for standard non-senf exceptions + + This class wraps an exception of type \a BaseException and adds functionality from + senf::ExceptionMixin. + + \ingroup exception + */ + template + class WrapException + : public ExceptionMixin, public BaseException + { + public: + typedef BaseException Base; + + WrapException(BaseException const & base); + virtual ~WrapException() throw(); + + virtual char const * what() const throw(); + }; + + /** \brief Wrap a non-senf exception + + This macro allows to wrap a non-senf exception adding functionality from ExceptionMixin + using the WrapException template. For an example, see \ref exception. + + \ingroup exception + */ +# define SENF_WRAP_EXC(Ex) \ + catch (Ex const & base) { \ + if (dynamic_cast(&base)) \ + throw; \ + else \ + throw senf::WrapException(base); \ + } + + template + typename boost::enable_if< boost::is_convertible, Exc & >::type + operator<<(Exc const & exc, 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 boost::lexical_cast and is + therefor identical to a streaming operation. + \see \ref exception */ + + +# ifdef SENF_DEBUG +# define _SENF_EXC_DEBUG_ARGS ,char const * file=0,int line=0 +# define _SENF_EXC_DEBUG_ARGS_ND ,char const *file,int line +# define _SENF_EXC_DEBUG_ARGS_P ,file,line +# else +# define _SENF_EXC_DEBUG_ARGS +# define _SENF_EXC_DEBUG_ARGS_ND +# define _SENF_EXC_DEBUG_ARGS_P +# endif + + /** \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: + + \code + // Standard usage: Take \c errno from environment + throw senf::SystemException("::open()") + << " while opening configuration file: " << filename; + + // 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 + + From within SENF (and only there because it depends on the \c SENF_DEBUG symbol), + SystemException should be thrown using wrapper macros which add additional information to + the exception description: + \code + // Standard usage: Take \c errno from environment + SENF_THROW_SYSTEM_EXCEPTION("::open()") + << " while opening configuration file: " << filename; + + // You may however explicitly specify the errno value + throw senf::SystemException("::open()", ENOFILE SENF_EXC_DEBUGINFO) + \endcode + + \ingroup exception + */ + class SystemException : public Exception + { + public: + /////////////////////////////////////////////////////////////////////////// + ///\name Structors and default members + ///@{ + + explicit SystemException(std::string const & descr = "" _SENF_EXC_DEBUG_ARGS); + explicit SystemException(int code _SENF_EXC_DEBUG_ARGS); + SystemException(std::string const & descr, int code _SENF_EXC_DEBUG_ARGS); + + virtual ~SystemException() throw(); + + ///@} + /////////////////////////////////////////////////////////////////////////// + + int errorNumber() const; ///< Error code (\c errno number) + char const * errorString() const; ///< Error string (\c 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 errorNumber() is one of \a c0 ... \a c9 + + + + private: + void init(std::string const & descr, int code _SENF_EXC_DEBUG_ARGS_ND); + + int code_; + }; + +# ifdef SENF_DEBUG +# define SENF_EXC_DEBUGINFO ,__FILE__,__LINE__ +# else +# define SENF_EXC_DEBUGINFO +# endif + +# define SENF_THROW_SYSTEM_EXCEPTION(desc) throw senf::SystemException(desc SENF_EXC_DEBUGINFO) + +} + +///////////////////////////////hh.e//////////////////////////////////////// +#include "Exception.cci" +//#include "Exception.ct" +#include "Exception.cti" +#endif + + +// Local Variables: +// mode: c++ +// fill-column: 100 +// c-file-style: "senf" +// indent-tabs-mode: nil +// ispell-local-dictionary: "american" +// compile-command: "scons -u test" +// comment-column: 40 +// End: +