mpv/stream/stream_file.c

/*
 * This file is part of MPlayer.
 *
 * Original authors: Albeu, probably Arpi
 *
 * MPlayer 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * MPlayer 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 MPlayer; 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 "mpvcore/mp_msg.h"
#include "stream.h"
#include "mpvcore/m_option.h"

struct priv {
    int fd;
    bool close;
};

static int fill_buffer(stream_t *s, char *buffer, int max_len)
{
    struct priv *p = s->priv;
    int r = read(p->fd, buffer, max_len);
    return (r <= 0) ? -1 : r;
}

static int write_buffer(stream_t *s, char *buffer, int len)
{
    struct priv *p = s->priv;
    int r;
    int wr = 0;
    while (wr < len) {
        r = write(p->fd, buffer, len);
        if (r <= 0)
            return -1;
        wr += r;
        buffer += r;
    }
    return len;
}

static int seek(stream_t *s, int64_t newpos)
{
    struct priv *p = s->priv;
    s->pos = newpos;
    if (lseek(p->fd, s->pos, SEEK_SET) < 0)
        return 0;
    return 1;
}

static int seek_forward(stream_t *s, int64_t newpos)
{
    if (newpos < s->pos) {
        mp_msg(MSGT_STREAM, MSGL_INFO,
               "Cannot seek backward in linear streams!\n");
        return 0;
    }
    while (s->pos < newpos) {
        int len = s->fill_buffer(s, s->buffer, STREAM_BUFFER_SIZE);
        if (len <= 0) { // EOF
            s->buf_pos = s->buf_len = 0;
            break;
        }
        s->buf_pos = 0;
        s->buf_len = len;
        s->pos += len;
    }
    return 1;
}

static int control(stream_t *s, int cmd, void *arg)
{
    struct priv *p = s->priv;
    switch (cmd) {
    case STREAM_CTRL_GET_SIZE: {
        off_t size;

        size = lseek(p->fd, 0, SEEK_END);
        lseek(p->fd, s->pos, SEEK_SET);
        if (size != (off_t)-1) {
            *(uint64_t *)arg = size;
            return 1;
        }
    }
    }
    return STREAM_UNSUPPORTED;
}

static void s_close(stream_t *s)
{
    struct priv *p = s->priv;
    if (p->close && p->fd >= 0)
        close(p->fd);
}

static int open_f(stream_t *stream, int mode)
{
    int fd;
    char *filename = stream->path;
    struct priv *priv = talloc_ptrtype(stream, priv);
    *priv = (struct priv) {
        .fd = -1
    };
    stream->priv = priv;

    mode_t m = 0;
    if (mode == STREAM_READ)
        m = O_RDONLY;
    else if (mode == STREAM_WRITE)
        m = O_RDWR | O_CREAT | O_TRUNC;
    else {
        mp_msg(MSGT_OPEN, MSGL_ERR, "[file] Unknown open mode %d\n", mode);
        return STREAM_UNSUPPORTED;
    }

    // "file://" prefix -> decode URL-style escapes
    if (strlen(stream->url) > strlen(stream->path))
        mp_url_unescape_inplace(stream->path);

#if HAVE_DOS_PATHS
    // extract '/' from '/x:/path'
    if (filename[0] == '/' && filename[1] && filename[2] == ':')
        filename++;
#endif

    if (!strcmp(filename, "-")) {
        if (mode == STREAM_READ) {
            mp_tmsg(MSGT_OPEN, MSGL_INFO, "Reading from stdin...\n");
            fd = 0;
#if HAVE_SETMODE
            setmode(fileno(stdin), O_BINARY);
#endif
        } else {
            mp_msg(MSGT_OPEN, MSGL_INFO, "Writing to stdout\n");
            fd = 1;
#if HAVE_SETMODE
            setmode(fileno(stdout), O_BINARY);
#endif
        }
        priv->fd = fd;
        priv->close = false;
    } else {
        mode_t openmode = S_IRUSR | S_IWUSR;
#ifndef __MINGW32__
        openmode |= S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
#endif
        fd = open(filename, m | O_BINARY, openmode);
        if (fd < 0) {
            mp_tmsg(MSGT_OPEN, MSGL_ERR, "Cannot open file '%s': %s\n",
                    filename, strerror(errno));
            return STREAM_ERROR;
        }
#ifndef __MINGW32__
        struct stat st;
        if (fstat(fd, &st) == 0 && S_ISDIR(st.st_mode)) {
            mp_tmsg(MSGT_OPEN, MSGL_ERR, "File is a directory: '%s'\n",
                    filename);
            close(fd);
            return STREAM_ERROR;
        }
#endif
        priv->fd = fd;
        priv->close = true;
    }

    int64_t len = lseek(fd, 0, SEEK_END);
    lseek(fd, 0, SEEK_SET);
#ifdef __MINGW32__
    // seeks on stdin incorrectly succeed on MinGW
    if (fd == 0)
        len = -1;
#endif
    stream->type = STREAMTYPE_FILE;
    if (len == -1 && mode == STREAM_READ) {
        stream->seek = seek_forward;
        stream->flags = MP_STREAM_SEEK_FW;
    } else if (len >= 0) {
        stream->seek = seek;
        stream->end_pos = len;
    }

    mp_msg(MSGT_OPEN, MSGL_V, "[file] File size is %" PRId64 " bytes\n", len);

    stream->fill_buffer = fill_buffer;
    stream->write_buffer = write_buffer;
    stream->control = control;
    stream->read_chunk = 64 * 1024;
    stream->close = s_close;

    return STREAM_OK;
}

const stream_info_t stream_info_file = {
    "file",
    open_f,
    { "file", "", NULL },
};