libisofs/src/stream.c

/*
 * Copyright (c) 2007 Vreixo Formoso
 * 
 * This file is part of the libisofs project; you can redistribute it and/or 
 * modify it under the terms of the GNU General Public License version 2 as 
 * published by the Free Software Foundation. See COPYING file for details.
 */

#include "libisofs.h"
#include "stream.h"
#include "fsource.h"
#include "error.h"

#include <stdlib.h>
#include <string.h>

typedef struct
{
    IsoFileSource *src;

    /* key for file identification inside filesystem */
    dev_t dev_id;
    ino_t ino_id;
    off_t size; /**< size of this file */
} FSrcStreamData;

static
int fsrc_open(IsoStream *stream)
{
    IsoFileSource *src;
    if (stream == NULL) {
        return ISO_NULL_POINTER;
    }
    src = ((FSrcStreamData*)stream->data)->src;
    return iso_file_source_open(src);
}

static
int fsrc_close(IsoStream *stream)
{
    IsoFileSource *src;
    if (stream == NULL) {
        return ISO_NULL_POINTER;
    }
    src = ((FSrcStreamData*)stream->data)->src;
    return iso_file_source_close(src);
}

static
off_t fsrc_get_size(IsoStream *stream)
{
    FSrcStreamData *data;
    data = (FSrcStreamData*)stream->data;

    return data->size;
}

static
int fsrc_read(IsoStream *stream, void *buf, size_t count)
{
    IsoFileSource *src;
    if (stream == NULL) {
        return ISO_NULL_POINTER;
    }
    src = ((FSrcStreamData*)stream->data)->src;
    return iso_file_source_read(src, buf, count);
}

static
int fsrc_is_repeatable(IsoStream *stream)
{
    int ret;
    struct stat info;
    FSrcStreamData *data;
    if (stream == NULL) {
        return ISO_NULL_POINTER;
    }
    data = (FSrcStreamData*)stream->data;

    /* mode is not cached, this function is only useful for filters */
    ret = iso_file_source_stat(data->src, &info);
    if (ret < 0) {
        return ret;
    }
    if (S_ISREG(info.st_mode) || S_ISBLK(info.st_mode)) {
        return 1;
    } else {
        return 0;
    }
}

static
int fsrc_get_id(IsoStream *stream, unsigned int *fs_id, dev_t *dev_id,
                ino_t *ino_id)
{
    FSrcStreamData *data;
    IsoFilesystem *fs;

    if (stream == NULL || fs_id == NULL || dev_id == NULL || ino_id == NULL) {
        return ISO_NULL_POINTER;
    }
    data = (FSrcStreamData*)stream->data;

    fs = iso_file_source_get_filesystem(data->src);

    *fs_id = fs->get_id(fs);
    if (fs_id == 0) {
        return 0;
    }

    *dev_id = data->dev_id;
    *ino_id = data->ino_id;
    return ISO_SUCCESS;
}

static
char *fsrc_get_name(IsoStream *stream)
{
    FSrcStreamData *data;
    data = (FSrcStreamData*)stream->data;
    return iso_file_source_get_path(data->src);
}

static
void fsrc_free(IsoStream *stream)
{
    FSrcStreamData *data;
    data = (FSrcStreamData*)stream->data;
    iso_file_source_unref(data->src);
    free(data);
}

IsoStreamIface fsrc_stream_class = {
    fsrc_open,
    fsrc_close,
    fsrc_get_size,
    fsrc_read,
    fsrc_is_repeatable,
    fsrc_get_id,
    fsrc_get_name,
    fsrc_free
};

int iso_file_source_stream_new(IsoFileSource *src, IsoStream **stream)
{
    int r;
    struct stat info;
    IsoStream *str;
    FSrcStreamData *data;

    if (src == NULL || stream == NULL) {
        return ISO_NULL_POINTER;
    }

    r = iso_file_source_stat(src, &info);
    if (r < 0) {
        return r;
    }
    if (S_ISDIR(info.st_mode)) {
        return ISO_FILE_IS_DIR;
    }
    
    /* check for read access to contents */
    r = iso_file_source_access(src);
    if (r < 0) {
        return r;
    }

    str = malloc(sizeof(IsoStream));
    if (str == NULL) {
        return ISO_MEM_ERROR;
    }
    data = malloc(sizeof(FSrcStreamData));
    if (str == NULL) {
        free(str);
        return ISO_MEM_ERROR;
    }

    /* take the ref to IsoFileSource */
    data->src = src;
    data->dev_id = info.st_dev;
    data->ino_id = info.st_ino;
    data->size = info.st_size;

    str->refcount = 1;
    str->data = data;
    str->class = &fsrc_stream_class;

    *stream = str;
    return ISO_SUCCESS;
}

void iso_stream_ref(IsoStream *stream)
{
    ++stream->refcount;
}

void iso_stream_unref(IsoStream *stream)
{
    if (--stream->refcount == 0) {
        stream->class->free(stream);
        free(stream);
    }
}