FileAccessor.cc

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/*
 * FileAccessor.cc
 *
 * Smalltalk like class library for C++
 * Accessor to file stored on disc.
 *
 * Copyright (c) 2003 Milan Cermak
 */
/*
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>

#include <stlib/FileAccessor.h>
#include <stlib/ByteArray.h>
#include <stlib/String.h>
#include <stlib/FileOpenFailed.h>

FileAccessor::FileAccessor(int fd)
{
    name = nil;
    descriptor = fd;
}

FileAccessor::FileAccessor(String *pathname, int rwMode, int creationRule)
{
    name = pathname;
    descriptor = open(pathname->asCString(), rwMode | creationRule,
                      S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
    if (descriptor < 0) {
        FileOpenFailed *error;
        error = new FileOpenFailed(new String(sys_errlist[errno]),
                                   __PRETTY_FUNCTION__, pathname);
        error->raise();
    }
}

FileAccessor::FileAccessor(const char *pathname, int rwMode, int creationRule)
{
    name = nil;
    descriptor = open(pathname, rwMode | creationRule,
                      S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
    if (descriptor < 0) {
        FileOpenFailed *error;
        error = new FileOpenFailed(new String(sys_errlist[errno]),
                                   __PRETTY_FUNCTION__, new String(pathname));
        error->raise();
    }
}

/* Class-accessing protocol */
String *FileAccessor::className(void) const
{
    return new String("FileAccessor");
}

/* Instance creation protocol */
FileAccessor *FileAccessor::openFileReadOnly(String *pathname)
{
    return new FileAccessor(pathname, O_RDONLY, 0);
}

FileAccessor *FileAccessor::openFileWriteOnly(String *pathname)
{
    return new FileAccessor(pathname, O_WRONLY, O_CREAT | O_TRUNC);
}

/* Initialize-release protocol */
void FileAccessor::close(void)
{
    ::close(descriptor);
    descriptor = -1;
}

/* Accessing protocol */
void FileAccessor::commit(void)
{
    fsync(descriptor);
}

long FileAccessor::dataSize(void)
{
    struct stat buf;
    fstat(descriptor, &buf);
    return buf.st_size;
}

LineEndConvention FileAccessor::lineEndConvention(void)
{
    return LineEndLF;
}

/* Data transfer protocol */
int FileAccessor::readInto(ByteArray *buffer, long startIndex, long count)
{
    unsigned char buf[count + 1];
    long size;

    size = read(descriptor, buf, count);
    if (size < 0) {
        perror(__PRETTY_FUNCTION__);
        error(new String("File read error"), new String(__PRETTY_FUNCTION__));
    }
    buffer->replace(startIndex, startIndex+size, buf);
    return size;
}

int FileAccessor::writeFrom(ByteArray *buffer, long startIndex, long count)
{
    const unsigned char *buf = buffer->rawBytesReadOnly();
    return write(descriptor, &buf[startIndex], count);
}

/* Positioning protocol */
void FileAccessor::seekTo(long position)
{
    lseek(descriptor, position, SEEK_SET);
}

/* Stream redirection protocol */
void FileAccessor::changeDescriptorTo(int fd)
{
    dup2(descriptor, fd);
    close();
    descriptor = fd;
}

/* Testing protocol */
bool FileAccessor::isSeekable(void)
{
    return true;
}

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