syscall_file.cpp

Go to the documentation of this file.

/***************************************************************************
 * lib/io/syscall_file.cpp
 *
 * Part of the STXXL. See http://stxxl.sourceforge.net
 *
 * Copyright (C) 2002 Roman Dementiev <[email protected]>
 * Copyright (C) 2008, 2010 Andreas Beckmann <[email protected]>
 * Copyright (C) 2010 Johannes Singler <[email protected]>
 *
 * 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)
 **************************************************************************/

#include <stxxl/bits/common/error_handling.h>
#include <stxxl/bits/common/mutex.h>
#include <stxxl/bits/config.h>
#include <stxxl/bits/io/iostats.h>
#include <stxxl/bits/io/request.h>
#include <stxxl/bits/io/request_interface.h>
#include <stxxl/bits/io/syscall_file.h>
#include "ufs_platform.h"


STXXL_BEGIN_NAMESPACE

void syscall_file::serve(const request* req) throw (io_error)
{
 scoped_mutex_lock fd_lock(fd_mutex);
 assert(req->get_file() == this);
 offset_type offset = req->get_offset();
 char* buffer = static_cast<char*>(req->get_buffer());
 size_type bytes = req->get_size();
 request::request_type type = req->get_type();

 stats::scoped_read_write_timer read_write_timer(bytes, type == request::WRITE);

 while (bytes > 0)
 {
 off_t rc = ::lseek(file_des, offset, SEEK_SET);
 if (rc < 0)
 {
 STXXL_THROW_ERRNO
 (io_error,
 " this=" << this <<
 " call=::lseek(fd,offset,SEEK_SET)" <<
 " path=" << filename <<
 " fd=" << file_des <<
 " offset=" << offset <<
 " buffer=" << (void*)buffer <<
 " bytes=" << bytes <<
 " type=" << ((type == request::READ) ? "READ" : "WRITE") <<
 " rc=" << rc);
 }

 if (type == request::READ)
 {
#if STXXL_MSVC
 assert(bytes <= std::numeric_limits<unsigned int>::max());
 if ((rc = ::read(file_des, buffer, (unsigned int)bytes)) <= 0)
#else
 if ((rc = ::read(file_des, buffer, bytes)) <= 0)
#endif
 {
 STXXL_THROW_ERRNO
 (io_error,
 " this=" << this <<
 " call=::read(fd,buffer,bytes)" <<
 " path=" << filename <<
 " fd=" << file_des <<
 " offset=" << offset <<
 " buffer=" << (void*)buffer <<
 " bytes=" << bytes <<
 " type=" << "READ" <<
 " rc=" << rc);
 }
 bytes -= rc;
 offset += rc;
 buffer += rc;

 if (bytes > 0 && offset == this->_size())
 {
 // read request extends past end-of-file
 // fill reminder with zeroes
 memset(buffer, 0, bytes);
 bytes = 0;
 }
 }
 else
 {
#if STXXL_MSVC
 assert(bytes <= std::numeric_limits<unsigned int>::max());
 if ((rc = ::write(file_des, buffer, (unsigned int)bytes)) <= 0)
#else
 if ((rc = ::write(file_des, buffer, bytes)) <= 0)
#endif
 {
 STXXL_THROW_ERRNO
 (io_error,
 " this=" << this <<
 " call=::write(fd,buffer,bytes)" <<
 " path=" << filename <<
 " fd=" << file_des <<
 " offset=" << offset <<
 " buffer=" << (void*)buffer <<
 " bytes=" << bytes <<
 " type=" << "WRITE" <<
 " rc=" << rc);
 }
 bytes -= rc;
 offset += rc;
 buffer += rc;
 }
 }
}

const char* syscall_file::io_type() const
{
 return "syscall";
}

STXXL_END_NAMESPACE
// vim: et:ts=4:sw=4