421 lines
12 KiB
C++
421 lines
12 KiB
C++
/* $Id$ */
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/*
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* Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com)
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* Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef __PJ_EXCEPTION_H__
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#define __PJ_EXCEPTION_H__
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/**
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* @file except.h
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* @brief Exception Handling in C.
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*/
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#include <pj/types.h>
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#include <pj/compat/setjmp.h>
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#include <pj/log.h>
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PJ_BEGIN_DECL
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/**
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* @defgroup PJ_EXCEPT Exception Handling
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* @ingroup PJ_MISC
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* @{
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*
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* \section pj_except_sample_sec Quick Example
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*
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* For the impatient, take a look at some examples:
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* - @ref page_pjlib_samples_except_c
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* - @ref page_pjlib_exception_test
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*
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* \section pj_except_except Exception Handling
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*
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* This module provides exception handling syntactically similar to C++ in
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* C language. In Win32 systems, it uses Windows Structured Exception
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* Handling (SEH) if macro PJ_EXCEPTION_USE_WIN32_SEH is non-zero.
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* Otherwise it will use setjmp() and longjmp().
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*
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* On some platforms where setjmp/longjmp is not available, setjmp/longjmp
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* implementation is provided. See <pj/compat/setjmp.h> for compatibility.
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*
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* The exception handling mechanism is completely thread safe, so the exception
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* thrown by one thread will not interfere with other thread.
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*
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* The exception handling constructs are similar to C++. The blocks will be
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* constructed similar to the following sample:
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*
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* \verbatim
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#define NO_MEMORY 1
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#define SYNTAX_ERROR 2
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int sample1()
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{
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PJ_USE_EXCEPTION; // declare local exception stack.
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PJ_TRY {
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...// do something..
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}
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PJ_CATCH(NO_MEMORY) {
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... // handle exception 1
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}
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PJ_END;
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}
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int sample2()
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{
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PJ_USE_EXCEPTION; // declare local exception stack.
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PJ_TRY {
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...// do something..
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}
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PJ_CATCH_ANY {
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if (PJ_GET_EXCEPTION() == NO_MEMORY)
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...; // handle no memory situation
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else if (PJ_GET_EXCEPTION() == SYNTAX_ERROR)
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...; // handle syntax error
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}
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PJ_END;
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}
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\endverbatim
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*
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* The above sample uses hard coded exception ID. It is @b strongly
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* recommended that applications request a unique exception ID instead
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* of hard coded value like above.
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*
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* \section pj_except_reg Exception ID Allocation
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*
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* To ensure that exception ID (number) are used consistently and to
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* prevent ID collisions in an application, it is strongly suggested that
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* applications allocate an exception ID for each possible exception
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* type. As a bonus of this process, the application can identify
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* the name of the exception when the particular exception is thrown.
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*
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* Exception ID management are performed with the following APIs:
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* - #pj_exception_id_alloc().
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* - #pj_exception_id_free().
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* - #pj_exception_id_name().
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*
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*
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* PJLIB itself automatically allocates one exception id, i.e.
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* #PJ_NO_MEMORY_EXCEPTION which is declared in <pj/pool.h>. This exception
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* ID is raised by default pool policy when it fails to allocate memory.
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*
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* CAVEATS:
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* - unlike C++ exception, the scheme here won't call destructors of local
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* objects if exception is thrown. Care must be taken when a function
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* hold some resorce such as pool or mutex etc.
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* - You CAN NOT make nested exception in one single function without using
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* a nested PJ_USE_EXCEPTION. Samples:
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\verbatim
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void wrong_sample()
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{
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PJ_USE_EXCEPTION;
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PJ_TRY {
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// Do stuffs
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...
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}
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PJ_CATCH_ANY {
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// Do other stuffs
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....
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..
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// The following block is WRONG! You MUST declare
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// PJ_USE_EXCEPTION once again in this block.
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PJ_TRY {
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..
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}
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PJ_CATCH_ANY {
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..
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}
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PJ_END;
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}
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PJ_END;
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}
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\endverbatim
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* - You MUST NOT exit the function inside the PJ_TRY block. The correct way
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* is to return from the function after PJ_END block is executed.
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* For example, the following code will yield crash not in this code,
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* but rather in the subsequent execution of PJ_TRY block:
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\verbatim
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void wrong_sample()
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{
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PJ_USE_EXCEPTION;
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PJ_TRY {
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// do some stuffs
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...
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return; <======= DO NOT DO THIS!
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}
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PJ_CATCH_ANY {
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}
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PJ_END;
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}
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\endverbatim
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* - You can not provide more than PJ_CATCH or PJ_CATCH_ANY nor use PJ_CATCH
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* and PJ_CATCH_ANY for a single PJ_TRY.
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* - Exceptions will always be caught by the first handler (unlike C++ where
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* exception is only caught if the type matches.
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* \section PJ_EX_KEYWORDS Keywords
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*
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* \subsection PJ_THROW PJ_THROW(expression)
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* Throw an exception. The expression thrown is an integer as the result of
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* the \a expression. This keyword can be specified anywhere within the
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* program.
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*
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* \subsection PJ_USE_EXCEPTION PJ_USE_EXCEPTION
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* Specify this in the variable definition section of the function block
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* (or any blocks) to specify that the block has \a PJ_TRY/PJ_CATCH exception
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* block.
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* Actually, this is just a macro to declare local variable which is used to
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* push the exception state to the exception stack.
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* Note: you must specify PJ_USE_EXCEPTION as the last statement in the
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* local variable declarations, since it may evaluate to nothing.
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*
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* \subsection PJ_TRY PJ_TRY
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* The \a PJ_TRY keyword is typically followed by a block. If an exception is
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* thrown in this block, then the execution will resume to the \a PJ_CATCH
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* handler.
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*
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* \subsection PJ_CATCH PJ_CATCH(expression)
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* The \a PJ_CATCH is normally followed by a block. This block will be executed
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* if the exception being thrown is equal to the expression specified in the
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* \a PJ_CATCH.
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*
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* \subsection PJ_CATCH_ANY PJ_CATCH_ANY
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* The \a PJ_CATCH is normally followed by a block. This block will be executed
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* if any exception was raised in the TRY block.
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*
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* \subsection PJ_END PJ_END
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* Specify this keyword to mark the end of \a PJ_TRY / \a PJ_CATCH blocks.
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*
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* \subsection PJ_GET_EXCEPTION PJ_GET_EXCEPTION(void)
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* Get the last exception thrown. This macro is normally called inside the
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* \a PJ_CATCH or \a PJ_CATCH_ANY block, altough it can be used anywhere where
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* the \a PJ_USE_EXCEPTION definition is in scope.
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*
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*
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* \section pj_except_examples_sec Examples
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*
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* For some examples on how to use the exception construct, please see:
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* - @ref page_pjlib_samples_except_c
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* - @ref page_pjlib_exception_test
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*/
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/**
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* Allocate a unique exception id.
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* Applications don't have to allocate a unique exception ID before using
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* the exception construct. However, by doing so it ensures that there is
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* no collisions of exception ID.
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*
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* As a bonus, when exception number is acquired through this function,
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* the library can assign name to the exception (only if
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* PJ_HAS_EXCEPTION_NAMES is enabled (default is yes)) and find out the
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* exception name when it catches an exception.
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*
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* @param name Name to be associated with the exception ID.
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* @param id Pointer to receive the ID.
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*
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* @return PJ_SUCCESS on success or PJ_ETOOMANY if the library
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* is running out out ids.
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*/
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PJ_DECL(pj_status_t) pj_exception_id_alloc(const char *name,
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pj_exception_id_t *id);
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/**
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* Free an exception id.
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*
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* @param id The exception ID.
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*
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* @return PJ_SUCCESS or the appropriate error code.
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*/
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PJ_DECL(pj_status_t) pj_exception_id_free(pj_exception_id_t id);
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/**
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* Retrieve name associated with the exception id.
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*
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* @param id The exception ID.
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*
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* @return The name associated with the specified ID.
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*/
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PJ_DECL(const char*) pj_exception_id_name(pj_exception_id_t id);
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/** @} */
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#if defined(PJ_EXCEPTION_USE_WIN32_SEH) && PJ_EXCEPTION_USE_WIN32_SEH != 0
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/*****************************************************************************
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**
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** IMPLEMENTATION OF EXCEPTION USING WINDOWS SEH
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**
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****************************************************************************/
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#define WIN32_LEAN_AND_MEAN
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#include <windows.h>
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PJ_IDECL_NO_RETURN(void)
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pj_throw_exception_(pj_exception_id_t id) PJ_ATTR_NORETURN
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{
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RaiseException(id,1,0,NULL);
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}
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#define PJ_USE_EXCEPTION
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#define PJ_TRY __try
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#define PJ_CATCH(id) __except(GetExceptionCode()==id ? \
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EXCEPTION_EXECUTE_HANDLER : \
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EXCEPTION_CONTINUE_SEARCH)
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#define PJ_CATCH_ANY __except(EXCEPTION_EXECUTE_HANDLER)
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#define PJ_END
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#define PJ_THROW(id) pj_throw_exception_(id)
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#define PJ_GET_EXCEPTION() GetExceptionCode()
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#elif defined(PJ_SYMBIAN) && PJ_SYMBIAN!=0
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/*****************************************************************************
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**
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** IMPLEMENTATION OF EXCEPTION USING SYMBIAN LEAVE/TRAP FRAMEWORK
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**
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****************************************************************************/
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/* To include this file, the source file must be compiled as
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* C++ code!
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*/
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#ifdef __cplusplus
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class TPjException
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{
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public:
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int code_;
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};
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#define PJ_USE_EXCEPTION
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#define PJ_TRY try
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//#define PJ_CATCH(id)
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#define PJ_CATCH_ANY catch (const TPjException & pj_excp_)
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#define PJ_END
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#define PJ_THROW(x_id) do { TPjException e; e.code_=x_id; throw e;} \
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while (0)
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#define PJ_GET_EXCEPTION() pj_excp_.code_
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#else
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#define PJ_USE_EXCEPTION
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#define PJ_TRY
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#define PJ_CATCH_ANY if (0)
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#define PJ_END
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#define PJ_THROW(x_id) do { PJ_LOG(1,("PJ_THROW"," error code = %d",x_id)); } while (0)
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#define PJ_GET_EXCEPTION() 0
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#endif /* __cplusplus */
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#else
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/*****************************************************************************
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**
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** IMPLEMENTATION OF EXCEPTION USING GENERIC SETJMP/LONGJMP
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**
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****************************************************************************/
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/**
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* This structure (which should be invisible to user) manages the TRY handler
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* stack.
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*/
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struct pj_exception_state_t
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{
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pj_jmp_buf state; /**< jmp_buf. */
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struct pj_exception_state_t *prev; /**< Previous state in the list. */
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};
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/**
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* Throw exception.
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* @param id Exception Id.
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*/
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PJ_DECL_NO_RETURN(void)
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pj_throw_exception_(pj_exception_id_t id) PJ_ATTR_NORETURN;
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/**
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* Push exception handler.
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*/
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PJ_DECL(void) pj_push_exception_handler_(struct pj_exception_state_t *rec);
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/**
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* Pop exception handler.
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*/
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PJ_DECL(void) pj_pop_exception_handler_(struct pj_exception_state_t *rec);
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/**
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* Declare that the function will use exception.
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* @hideinitializer
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*/
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#define PJ_USE_EXCEPTION struct pj_exception_state_t pj_x_except__; int pj_x_code__
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/**
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* Start exception specification block.
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* @hideinitializer
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*/
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#define PJ_TRY if (1) { \
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pj_push_exception_handler_(&pj_x_except__); \
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pj_x_code__ = pj_setjmp(pj_x_except__.state); \
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if (pj_x_code__ == 0)
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/**
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* Catch the specified exception Id.
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* @param id The exception number to catch.
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* @hideinitializer
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*/
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#define PJ_CATCH(id) else if (pj_x_code__ == (id))
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/**
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* Catch any exception number.
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* @hideinitializer
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*/
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#define PJ_CATCH_ANY else
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/**
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* End of exception specification block.
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* @hideinitializer
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*/
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#define PJ_END pj_pop_exception_handler_(&pj_x_except__); \
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} else {}
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/**
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* Throw exception.
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* @param exception_id The exception number.
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* @hideinitializer
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*/
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#define PJ_THROW(exception_id) pj_throw_exception_(exception_id)
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/**
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* Get current exception.
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* @return Current exception code.
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* @hideinitializer
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*/
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#define PJ_GET_EXCEPTION() (pj_x_code__)
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#endif /* PJ_EXCEPTION_USE_WIN32_SEH */
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PJ_END_DECL
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#endif /* __PJ_EXCEPTION_H__ */
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