mariadb-columnstore-engine/utils/idbdatafile/BufferedFile.cpp

/* Copyright (C) 2014 InfiniDB, Inc.

   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; version 2 of
   the License.

   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., 51 Franklin Street, Fifth Floor, Boston,
   MA 02110-1301, USA. */

#include <stdio.h>
#include <string>
#include <sys/stat.h>
#include <sstream>
#include <iostream>
#ifdef _MSC_VER
#define WIN32_LEAN_AND_MEAN
#define NOMINMAX
#include <io.h>
#include <windows.h>
#endif
#include "utility.h"
#include "BufferedFile.h"
#include "IDBLogger.h"
using namespace std;

namespace idbdatafile
{

BufferedFile::BufferedFile(const char* fname, const char* mode, unsigned opts) :
    IDBDataFile( fname ),
    m_fp( 0 ),
    m_buffer( 0 )
{
    m_fp = fopen(fname, mode);

    if ( m_fp == NULL )
    {
        throw std::runtime_error("unable to open Buffered file ");
    }

    applyOptions( opts );
}

void	BufferedFile::applyOptions( unsigned opts )
{
    if ( opts & IDBDataFile::USE_VBUF )
    {
        const int DEFAULT_BUFSIZ = 1 * 1024 * 1024;
        m_buffer = new char[DEFAULT_BUFSIZ];
        setvbuf(m_fp, m_buffer, _IOFBF, DEFAULT_BUFSIZ);
    }
    else if ( opts & IDBDataFile::USE_NOVBUF )
    {
        setvbuf(m_fp, NULL, _IONBF, 0);
    }
}

BufferedFile::~BufferedFile()
{
    close();
    m_fp = 0;
    delete [] m_buffer;
}

ssize_t BufferedFile::pread(void* ptr, off64_t offset, size_t count)
{
    ssize_t ret = 0;
    int savedErrno;
    ssize_t curpos = tell();

    seek(offset, SEEK_SET);
    ret = read(ptr, count);
    savedErrno = errno;
    seek(curpos, SEEK_SET);

    if ( IDBLogger::isEnabled() )
        IDBLogger::logRW("pread", m_fname, this, offset, count, ret);

    errno = savedErrno;
    return ret;
}

ssize_t BufferedFile::read(void* ptr, size_t count)
{
    ssize_t ret = 0;
    ssize_t offset = tell();
    int savedErrno = -1;
    size_t progress = 0;
    uint8_t* ptr8 = (uint8_t*) ptr;

    while (progress < count)
    {
        ret = fread(ptr8 + progress, 1, count - progress, m_fp);
        savedErrno = errno;

        if (ret <= 0)
        {
            if (ferror(m_fp))
            {
                errno = savedErrno;
                return -1;
            }
            else if (feof(m_fp))
                return progress;
        }

        progress += ret;
    }

    if ( IDBLogger::isEnabled() )
        IDBLogger::logRW("read", m_fname, this, offset, count, progress);

    errno = savedErrno;
    return progress;
}

ssize_t BufferedFile::write(const void* ptr, size_t count)
{
    ssize_t ret = 0;
    off64_t offset = tell();
    int savedErrno = 0;
    size_t progress = 0;
    uint8_t* ptr8 = (uint8_t*) ptr;

    while (progress < count)
    {
        ret = fwrite(ptr8 + progress, 1, count - progress, m_fp);
        savedErrno = errno;

        if (ret <= 0 && ferror(m_fp))
        {
            errno = savedErrno;
            return -1;
        }
        else if (ret > 0)
            progress += ret;

        // can fwrite() continually return 0 with no error?
    }

    if ( IDBLogger::isEnabled() )
        IDBLogger::logRW("write", m_fname, this, offset, count, progress);

    errno = savedErrno;
    return progress;
}

int BufferedFile::seek(off64_t offset, int whence)
{
    int ret = 0;
    int savedErrno;
#ifdef _MSC_VER
    ret = _fseeki64(m_fp, offset, whence);
#else
    ret = fseek(m_fp, offset, whence);
#endif
    savedErrno = errno;

    if ( IDBLogger::isEnabled() )
        IDBLogger::logSeek(m_fname, this, offset, whence, ret);

    errno = savedErrno;
    return ret;
}

int BufferedFile::truncate(off64_t length)
{
    int ret = 0;
    int savedErrno;

#ifdef _MSC_VER
    ret = _chsize_s(_fileno(m_fp), length);
#else
    ret = ftruncate(fileno(m_fp), length);
#endif
    savedErrno = errno;

    if ( IDBLogger::isEnabled() )
        IDBLogger::logTruncate(m_fname, this, length, ret);

    errno = savedErrno;
    return ret;
}

off64_t BufferedFile::size()
{
#ifdef _MSC_VER
    return _filelengthi64(fileno(m_fp));    // Interestingly, implemented as fseek/ftell in the windows crt
#else
    // going to calculate size 2 ways - first, via seek
    off64_t length = -1;
    off64_t here;

    flockfile(m_fp);

    try
    {
        if ((here = ftell(m_fp)) > -1)
        {
            if (fseek(m_fp, 0, SEEK_END) > -1)
            {
                length = ftell(m_fp);
                fseek(m_fp, here, SEEK_SET);
            }
        }

        funlockfile(m_fp);
    }
    catch (...)
    {
        funlockfile(m_fp);
    }

    return length;
#endif
}

off64_t BufferedFile::tell()
{
#ifdef _MSC_VER
    return _ftelli64(m_fp);
#else
    return ftell(m_fp);
#endif
}

int BufferedFile::flush()
{
    int rc = fflush(m_fp);
    int savedErrno = errno;

    if ( rc == 0 )
    {
#ifdef _MSC_VER
        rc = _commit(_fileno(m_fp));
#else
        rc = fsync( fileno( m_fp ) );
#endif
        savedErrno = errno;
    }

    if ( IDBLogger::isEnabled() )
        IDBLogger::logNoArg(m_fname, this, "flush", rc);

    errno = savedErrno;
    return rc;
}

time_t BufferedFile::mtime()
{
    time_t ret = 0;
    struct stat statbuf;

    if (::fstat(fileno(m_fp), &statbuf) == 0)
        ret = statbuf.st_mtime;
    else
        ret = (time_t) - 1;

    return ret;
}

int BufferedFile::close()
{
    int ret = fclose(m_fp);
    int savedErrno = errno;

    if ( IDBLogger::isEnabled() )
        IDBLogger::logNoArg(m_fname, this, "close", ret);

    errno = savedErrno;
    return ret;
}

}