mirror of
https://github.com/matrix-construct/construct
synced 2024-12-24 22:43:56 +01:00
148 lines
6.2 KiB
C++
148 lines
6.2 KiB
C++
/*
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* charybdis: 21st Century IRCd
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* exception.h: Exception root
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*
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* Copyright (C) 2016 Charybdis Development Team
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* Copyright (C) 2016 Jason Volk <jason@zemos.net>
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice is present in all copies.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#pragma once
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#define HAVE_IRCD_EXCEPTION_H
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namespace ircd {
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/** The root exception type.
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*
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* All exceptions in the project inherit from this type.
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* To catch any exception from a project developer's code:
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* catch(const ircd::exception &) {}
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*
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* Remember: not all exceptions are from project developer's code,
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* such as std::out_of_range. In most contexts if you have to deal with this
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* someone else was lazy, which is bad. To be sure and catch any exception:
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* catch(const std::exception &) {}
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*
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* Remember: not all exceptions have to inherit from std::exception, but
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* those are rogue exceptions. We do not allow this. To be sure nothing
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* can possibly get through, add to the bottom:
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* catch(...) {}
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*
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* Note: Prefer 'noexcept' instead of catch(...), noexcept is like an 'assert'
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* for exceptions, and the rogue can be found-out in testing.
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*/
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struct exception
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:std::exception
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{
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protected:
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IRCD_OVERLOAD(generate_skip)
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char buf[BUFSIZE];
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ssize_t generate(const char *const &name, const char *const &fmt, const va_rtti &ap) noexcept;
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ssize_t generate(const char *const &fmt, const va_rtti &ap) noexcept;
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public:
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const char *what() const noexcept override
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{
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return buf;
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}
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exception(const generate_skip_t = {}) noexcept
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{
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buf[0] = '\0';
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}
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};
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/** Exception generator convenience macro
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*
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* If you want to create your own exception type, you have found the right
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* place! This macro allows creating an exception in the the hierarchy.
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*
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* To create an exception, invoke this macro in your header. Examples:
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*
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* IRCD_EXCEPTION(ircd::exception, my_exception)
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* IRCD_EXCEPTION(my_exception, my_specific_exception)
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*
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* Then your catch sequence can look like the following:
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*
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* catch(const my_specific_exception &e)
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* {
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* log("something specifically bad happened: %s", e.what());
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* }
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* catch(const my_exception &e)
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* {
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* log("something generically bad happened: %s", e.what());
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* }
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* catch(const ircd::exception &e)
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* {
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* log("unrelated bad happened: %s", e.what());
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* }
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* catch(const std::exception &e)
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* {
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* log("unhandled bad happened: %s", e.what());
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* }
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*
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* Remember: the order of the catch blocks is important.
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*/
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#define IRCD_EXCEPTION(parent, name) \
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struct name \
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:parent \
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{ \
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template<class... args> \
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name(const char *const &fmt = " ", args&&... ap) noexcept \
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:parent{generate_skip} \
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{ \
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generate(#name, fmt, va_rtti{std::forward<args>(ap)...}); \
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} \
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\
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name(generate_skip_t) noexcept \
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:parent{generate_skip} \
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{ \
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} \
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}; \
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#define IRCD_EXCEPTION_HIDENAME(parent, name) \
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struct name \
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:parent \
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{ \
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template<class... args> \
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name(const char *const &fmt = " ", args&&... ap) noexcept \
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:parent{generate_skip} \
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{ \
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generate(fmt, va_rtti{std::forward<args>(ap)...}); \
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} \
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\
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name(generate_skip_t = {}) noexcept \
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:parent{generate_skip} \
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{ \
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} \
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};
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/** Root error exception type. Inherit from this.
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* List your own exception somewhere else (unless you're overhauling libircd).
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* example, in your namespace:
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*
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* IRCD_EXCEPTION(ircd::error, error)
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*/
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IRCD_EXCEPTION(exception, error) // throw ircd::error("something bad")
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IRCD_EXCEPTION(error, user_error) // throw ircd::user_error("something silly")
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} // namespace ircd
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