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//Copyright (c) 2006-2009 Emil Dotchevski and Reverge Studios, Inc.
//Distributed under the Boost Software License, Version 1.0. (See accompanying
//file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//This program simulates errors on copying simple data files. It demonstrates
//typical Boost Exception usage.
//The output from this program can vary depending on the platform.
#include <boost/throw_exception.hpp>
#include <boost/exception/info.hpp>
#include <boost/exception/get_error_info.hpp>
#include <boost/exception/diagnostic_information.hpp>
#include <boost/exception/errinfo_file_open_mode.hpp>
#include <boost/exception/errinfo_file_handle.hpp>
#include <boost/exception/errinfo_file_name.hpp>
#include <boost/exception/errinfo_api_function.hpp>
#include <boost/exception/errinfo_errno.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/weak_ptr.hpp>
#include <iostream>
typedef boost::error_info<struct tag_file_name_src,std::string> errinfo_src_file_name;
typedef boost::error_info<struct tag_file_name_dst,std::string> errinfo_dst_file_name;
char const data[] = "example";
size_t const data_size = sizeof(data);
class
error: //Base for all exception objects we throw.
public virtual std::exception,
public virtual boost::exception
{
public:
char const *
what() const BOOST_NOEXCEPT_OR_NOTHROW
{
return "example_io error";
}
protected:
~error() BOOST_NOEXCEPT_OR_NOTHROW
{
}
};
struct open_error: virtual error { };
struct read_error: virtual error { };
struct write_error: virtual error { };
struct fopen_error: virtual open_error { };
struct fread_error: virtual read_error { };
struct fwrite_error: virtual write_error { };
boost::shared_ptr<FILE>
my_fopen( char const * name, char const * mode )
{
if( FILE * f = ::fopen(name,mode) )
return boost::shared_ptr<FILE>(f,fclose);
else
BOOST_THROW_EXCEPTION(fopen_error() <<
boost::errinfo_errno (errno) <<
boost::errinfo_file_name(name) <<
boost::errinfo_file_open_mode(mode) <<
boost::errinfo_api_function("fopen"));
}
void
my_fread( void * buffer, size_t size, size_t count, boost::shared_ptr<FILE> const & stream )
{
assert(stream);
if( count!=fread(buffer,size,count,stream.get()) || ferror(stream.get()) )
BOOST_THROW_EXCEPTION(fread_error() <<
boost::errinfo_api_function("fread") <<
boost::errinfo_errno(errno) <<
boost::errinfo_file_handle(boost::weak_ptr<FILE>(stream)));
}
void
my_fwrite( void const * buffer, size_t size, size_t count, boost::shared_ptr<FILE> const & stream )
{
assert(stream);
if( count!=fwrite(buffer,size,count,stream.get()) || ferror(stream.get()) )
BOOST_THROW_EXCEPTION(fwrite_error() <<
boost::errinfo_api_function("fwrite") <<
boost::errinfo_errno(errno) <<
boost::errinfo_file_handle(boost::weak_ptr<FILE>(stream)));
}
void
reset_file( char const * file_name )
{
(void) my_fopen(file_name,"wb");
}
void
create_data( char const * file_name )
{
boost::shared_ptr<FILE> f = my_fopen(file_name,"wb");
my_fwrite( data, 1, data_size, f );
}
void
copy_data( char const * src_file_name, char const * dst_file_name )
{
boost::shared_ptr<FILE> src = my_fopen(src_file_name,"rb");
boost::shared_ptr<FILE> dst = my_fopen(dst_file_name,"wb");
try
{
char buffer[data_size];
my_fread( buffer, 1, data_size, src );
my_fwrite( buffer, 1, data_size, dst );
}
catch(
boost::exception & x )
{
if( boost::weak_ptr<FILE> const * f=boost::get_error_info<boost::errinfo_file_handle>(x) )
if( boost::shared_ptr<FILE> fs = f->lock() )
{
if( fs==src )
x << boost::errinfo_file_name(src_file_name);
else if( fs==dst )
x << boost::errinfo_file_name(dst_file_name);
}
x <<
errinfo_src_file_name(src_file_name) <<
errinfo_dst_file_name(dst_file_name);
throw;
}
}
void
dump_copy_info( boost::exception const & x )
{
if( std::string const * src = boost::get_error_info<errinfo_src_file_name>(x) )
std::cerr << "Source file name: " << *src << "\n";
if( std::string const * dst = boost::get_error_info<errinfo_dst_file_name>(x) )
std::cerr << "Destination file name: " << *dst << "\n";
}
void
dump_file_info( boost::exception const & x )
{
if( std::string const * fn = boost::get_error_info<boost::errinfo_file_name>(x) )
std::cerr << "File name: " << *fn << "\n";
}
void
dump_clib_info( boost::exception const & x )
{
if( int const * err=boost::get_error_info<boost::errinfo_errno>(x) )
std::cerr << "OS error: " << *err << "\n";
if( char const * const * fn=boost::get_error_info<boost::errinfo_api_function>(x) )
std::cerr << "Failed function: " << *fn << "\n";
}
void
dump_all_info( boost::exception const & x )
{
std::cerr << "-------------------------------------------------\n";
dump_copy_info(x);
dump_file_info(x);
dump_clib_info(x);
std::cerr << "\nOutput from diagnostic_information():\n";
std::cerr << diagnostic_information(x);
}
int
main()
{
try
{
create_data( "tmp1.txt" );
copy_data( "tmp1.txt", "tmp2.txt" ); //This should succeed.
reset_file( "tmp1.txt" ); //Creates empty file.
try
{
copy_data( "tmp1.txt", "tmp2.txt" ); //This should fail, tmp1.txt is empty.
}
catch(
read_error & x )
{
std::cerr << "\nCaught 'read_error' exception.\n";
dump_all_info(x);
}
remove( "tmp1.txt" );
remove( "tmp2.txt" );
try
{
copy_data( "tmp1.txt", "tmp2.txt" ); //This should fail, tmp1.txt does not exist.
}
catch(
open_error & x )
{
std::cerr << "\nCaught 'open_error' exception.\n";
dump_all_info(x);
}
}
catch(
... )
{
std::cerr << "\nCaught unexpected exception!\n";
std::cerr << boost::current_exception_diagnostic_information();
}
}
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