mpv/stream/stream_rar.c

// Major parts based on:
/*****************************************************************************
 * access.c: uncompressed RAR access
 *****************************************************************************
 * Copyright (C) 2008-2010 Laurent Aimar
 * $Id: dcd973529e0029abe326d31f8d58cd13bbcc276c $
 *
 * Author: Laurent Aimar <fenrir _AT_ videolan _DOT_ org>
 *
 * This program 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 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser 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 "config.h"

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>

#include "osdep/io.h"

#include "common/msg.h"
#include "stream.h"
#include "options/m_option.h"
#include "rar.h"

/*
This works as follows:

- stream_open() with file01.rar
    - is opened as normal file (stream_file.c or others) first
    - demux_rar.c detects it
    - if multi-part, opens file02.rar, file03.rar, etc. as actual streams
    - it returns a playlist with entries like this to the player:
        rar://bla01.rar|subfile.mkv
      (one such entry for each file contained in the rar)
- stream_open() with the playlist entry, e.g. rar://bla01.rar|subfile.mkv
    - leads to rar_entry_open()
    - opens bla01.rar etc. again as actual streams
    - read accesses go into subfile.mkv contained in the rar file(s)
*/

static int rar_entry_fill_buffer(stream_t *s, char *buffer, int max_len)
{
    rar_file_t *rar_file = s->priv;
    return RarRead(rar_file, buffer, max_len);
}

static int rar_entry_seek(stream_t *s, int64_t newpos)
{
    rar_file_t *rar_file = s->priv;
    return RarSeek(rar_file, newpos);
}

static void rar_entry_close(stream_t *s)
{
    rar_file_t *rar_file = s->priv;
    RarFileDelete(rar_file);
}

static int rar_entry_control(stream_t *s, int cmd, void *arg)
{
    rar_file_t *rar_file = s->priv;
    switch (cmd) {
    case STREAM_CTRL_GET_BASE_FILENAME:
        *(char **)arg = talloc_strdup(NULL, rar_file->s->url);
        return STREAM_OK;
    case STREAM_CTRL_GET_SIZE:
        *(int64_t *)arg = rar_file->size;
        return STREAM_OK;
    }
    return STREAM_UNSUPPORTED;
}

static int rar_entry_open(stream_t *stream)
{
    if (!strchr(stream->path, '|'))
        return STREAM_ERROR;

    char *base = talloc_strdup(stream, stream->path);
    char *name = strchr(base, '|');
    *name++ = '\0';
    mp_url_unescape_inplace(base);

    struct stream *rar = stream_create(base, STREAM_READ | STREAM_SAFE_ONLY,
                                       stream->cancel, stream->global);
    if (!rar)
        return STREAM_ERROR;

    int count;
    rar_file_t **files;
    if (RarProbe(rar) || RarParse(rar, &count, &files)) {
        free_stream(rar);
        return STREAM_ERROR;
    }

    rar_file_t *file = NULL;
    for (int i = 0; i < count; i++) {
        if (!file && strcmp(files[i]->name, name) == 0)
            file = files[i];
        else
            RarFileDelete(files[i]);
    }
    talloc_free(files);
    if (!file) {
        free_stream(rar);
        return STREAM_ERROR;
    }

    rar_file_chunk_t dummy = {
        .mrl = base,
    };
    file->current_chunk = &dummy;
    file->s = rar; // transfer ownership
    file->cancel = stream->cancel;
    file->global = stream->global;
    RarSeek(file, 0);

    stream->priv = file;
    stream->fill_buffer = rar_entry_fill_buffer;
    stream->seek = rar_entry_seek;
    stream->seekable = true;
    stream->close = rar_entry_close;
    stream->control = rar_entry_control;

    return STREAM_OK;
}

const stream_info_t stream_info_rar = {
    .name = "rar",
    .open = rar_entry_open,
    .protocols = (const char*const[]){ "rar", NULL },
};