Re: [libdvdcss-devel] [PATCH] Add dvdcss_open_stream() API function

Thanks you very much for rebasing it on top of your work.

I didn't have the time yet to rewrite this patch, a bug fix on vlc took
more time than expected.

If I remember correctly, the only point we weren't sure was about seek
offset and read pos.
Use pos/offset in byte or in block (2048, right ?).


On Wed, Oct 29, 2014, at 22:18, Diego Biurrun wrote:
> From: Thomas Guillem <[email protected]>
> 
> This allows opening a DVD device using external read/seek callbacks.
> ---
> 
> A fresh version of the patch, rebased on top of my cleanup and with most
> of my review comments addressed so that we have a cleaner basis for
> further discussion.
> 
>  NEWS                |   2 +
>  src/device.c        | 109
>  +++++++++++++++++++++++++++++++++++++++++++++++++++-
>  src/dvdcss/dvdcss.h |  12 ++++++
>  src/libdvdcss.c     |  30 +++++++++++++++
>  src/libdvdcss.h     |   3 ++
>  5 files changed, 154 insertions(+), 2 deletions(-)
> 
> diff --git a/NEWS b/NEWS
> index d3fdaed..e542020 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -7,6 +7,8 @@ Changes between 1.2.13 and 1.3.0:
>      - the variable dvdcss_interface_2
>    * Support for Android
>    * Drop support for HP-UX, Solaris, BeOS, QNX, OS/2, and Windows 9x.
> +  * Add dvdcss_open_stream() to public API. This allows installing
> custom
> +    callback functions for accessing DVD, e.g. over the network.
>    * Miscellaneous cleanups to code, documentation, build system.
>  
>  
> diff --git a/src/device.c b/src/device.c
> index ed2b710..8b4a50e 100644
> --- a/src/device.c
> +++ b/src/device.c
> @@ -74,6 +74,10 @@ static int libc_seek  ( dvdcss_t, int );
>  static int libc_read  ( dvdcss_t, void *, int );
>  static int libc_readv ( dvdcss_t, struct iovec *, int );
>  
> +static int stream_seek  ( dvdcss_t, int );
> +static int stream_read  ( dvdcss_t, void *, int );
> +static int stream_readv ( dvdcss_t, struct iovec *, int );
> +
>  #ifdef WIN32
>  static int win2k_open  ( dvdcss_t, const char * );
>  static int win2k_seek  ( dvdcss_t, int );
> @@ -83,6 +87,9 @@ static int win2k_readv ( dvdcss_t, struct iovec *, int
> );
>  
>  int dvdcss_use_ioctls( dvdcss_t dvdcss )
>  {
> +    if( dvdcss->p_stream )
> +        return 0;
> +
>  #if defined( WIN32 )
>      if( dvdcss->b_file )
>      {
> @@ -141,8 +148,8 @@ void dvdcss_check_device ( dvdcss_t dvdcss )
>      int i, i_fd;
>  #endif
>  
> -    /* If the device name is non-null, return */
> -    if( dvdcss->psz_device[0] )
> +    /* If the device name is non-NULL or stream is set, return. */
> +    if( dvdcss->psz_device[0] || dvdcss->p_stream )
>      {
>          return;
>      }
> @@ -273,6 +280,16 @@ int dvdcss_open_device ( dvdcss_t dvdcss )
>  
>      print_debug( dvdcss, "opening target `%s'", psz_device );
>  
> +    /* if callback functions are initialized */
> +    if( dvdcss->p_stream )
> +    {
> +        print_debug( dvdcss, "using stream API for access" );
> +        dvdcss->pf_seek  = stream_seek;
> +        dvdcss->pf_read  = stream_read;
> +        dvdcss->pf_readv = stream_readv;
> +        return 0;
> +    }
> +
>  #if defined( WIN32 )
>      dvdcss->b_file = 1;
>      /* If device is "X:" or "X:\", we are not actually opening a file.
>      */
> @@ -446,6 +463,31 @@ static int libc_seek( dvdcss_t dvdcss, int i_blocks
> )
>      return dvdcss->i_pos;
>  }
>  
> +static int stream_seek( dvdcss_t dvdcss, int i_blocks )
> +{
> +    off_t i_seek = i_blocks * DVDCSS_BLOCK_SIZE;
> +
> +    if( !dvdcss->p_stream_cb->pf_seek )
> +        return -1;
> +
> +    if( dvdcss->i_pos == i_blocks )
> +    {
> +        /* We are already in position */
> +        return i_blocks;
> +    }
> +
> +    if( dvdcss->p_stream_cb->pf_seek( dvdcss->p_stream, i_seek ) != 0 )
> +    {
> +        print_error( dvdcss, "seek error" );
> +        dvdcss->i_pos = -1;
> +        return -1;
> +    }
> +
> +    dvdcss->i_pos = i_blocks;
> +
> +    return dvdcss->i_pos;
> +}
> +
>  #if defined( WIN32 )
>  static int win2k_seek( dvdcss_t dvdcss, int i_blocks )
>  {
> @@ -514,6 +556,46 @@ static int libc_read ( dvdcss_t dvdcss, void
> *p_buffer, int i_blocks )
>      return i_ret_blocks;
>  }
>  
> +static int stream_read ( dvdcss_t dvdcss, void *p_buffer, int i_blocks )
> +{
> +    off_t i_size, i_ret, i_ret_blocks;
> +
> +    i_size = i_blocks * DVDCSS_BLOCK_SIZE;
> +
> +    if( !dvdcss->p_stream_cb->pf_read )
> +        return -1;
> +
> +    i_ret = dvdcss->p_stream_cb->pf_read( dvdcss->p_stream, p_buffer,
> i_size );
> +
> +    if( i_ret < 0 )
> +    {
> +        print_error( dvdcss, "read error" );
> +        dvdcss->i_pos = -1;
> +        return i_ret;
> +    }
> +
> +    i_ret_blocks = i_ret / DVDCSS_BLOCK_SIZE;
> +
> +    /* Handle partial reads */
> +    if( i_ret != i_size )
> +    {
> +        int i_seek;
> +
> +        dvdcss->i_pos = -1;
> +        i_seek = stream_seek( dvdcss, i_ret_blocks );
> +        if( i_seek < 0 )
> +        {
> +            return i_seek;
> +        }
> +
> +        /* We have to return now so that i_pos isn't clobbered */
> +        return i_ret_blocks;
> +    }
> +
> +    dvdcss->i_pos += i_ret_blocks;
> +    return i_ret_blocks;
> +}
> +
>  #if defined( WIN32 )
>  static int win2k_read ( dvdcss_t dvdcss, void *p_buffer, int i_blocks )
>  {
> @@ -605,6 +687,29 @@ static int libc_readv ( dvdcss_t dvdcss, struct
> iovec *p_iovec, int i_blocks )
>  #endif
>  }
>  
> +/*****************************************************************************
> + * stream_readv: vectored read
> +
> *****************************************************************************/
> +static int stream_readv ( dvdcss_t dvdcss, struct iovec *p_iovec, int
> i_blocks )
> +{
> +    int i_read;
> +
> +    if( !dvdcss->p_stream_cb->pf_readv )
> +        return -1;
> +
> +    i_read = dvdcss->p_stream_cb->pf_readv( dvdcss->p_stream, p_iovec,
> +                                            i_blocks );
> +
> +    if( i_read < 0 )
> +    {
> +        dvdcss->i_pos = -1;
> +        return i_read;
> +    }
> +
> +    dvdcss->i_pos += i_read / DVDCSS_BLOCK_SIZE;
> +    return i_read / DVDCSS_BLOCK_SIZE;
> +}
> +
>  #if defined( WIN32 )
>  /*****************************************************************************
>   * win2k_readv: vectored read using ReadFile for Win2K
> diff --git a/src/dvdcss/dvdcss.h b/src/dvdcss/dvdcss.h
> index 64f95cf..5e1a77b 100644
> --- a/src/dvdcss/dvdcss.h
> +++ b/src/dvdcss/dvdcss.h
> @@ -31,6 +31,8 @@
>  #define DVDCSS_DVDCSS_H 1
>  #endif
>  
> +#include <stdint.h>
> +
>  #ifdef __cplusplus
>  extern "C" {
>  #endif
> @@ -38,6 +40,14 @@ extern "C" {
>  /** Library instance handle, to be used for each library call. */
>  typedef struct dvdcss_s* dvdcss_t;
>  
> +struct dvdcss_stream_cb
> +{
> +    int ( *pf_seek )  ( void *p_stream, uint64_t i_pos);
> +    int ( *pf_read )  ( void *p_stream, void *buffer, int i_read);
> +    int ( *pf_readv ) ( void *p_stream, void *p_iovec, int i_blocks);
> +};
> +typedef struct dvdcss_stream_cb dvdcss_stream_cb;
> +
>  
>  /** The block size of a DVD. */
>  #define DVDCSS_BLOCK_SIZE      2048
> @@ -73,6 +83,8 @@ typedef struct dvdcss_s* dvdcss_t;
>   * Exported prototypes.
>   */
>  LIBDVDCSS_EXPORT dvdcss_t dvdcss_open  ( const char *psz_target );
> +LIBDVDCSS_EXPORT dvdcss_t dvdcss_open_stream( void *p_stream,
> +                                              dvdcss_stream_cb
> *p_stream_cb );
>  LIBDVDCSS_EXPORT int      dvdcss_close ( dvdcss_t );
>  LIBDVDCSS_EXPORT int      dvdcss_seek  ( dvdcss_t,
>                                 int i_blocks,
> diff --git a/src/libdvdcss.c b/src/libdvdcss.c
> index ab5b665..6d622ac 100644
> --- a/src/libdvdcss.c
> +++ b/src/libdvdcss.c
> @@ -135,6 +135,8 @@
>  #define mkdir(a, b) _mkdir(a)
>  #endif
>  
> +static dvdcss_t dvdcss_open_common ( const char *psz_target, void
> *p_stream,
> +                                     dvdcss_stream_cb *p_stream_cb );
>  static void set_verbosity( dvdcss_t dvdcss )
>  {
>      const char *psz_verbose = getenv( "DVDCSS_VERBOSE" );
> @@ -416,6 +418,27 @@ static void create_cache_dir( dvdcss_t dvdcss, const
> char *psz_cache )
>   */
>  LIBDVDCSS_EXPORT dvdcss_t dvdcss_open ( const char *psz_target )
>  {
> +    return dvdcss_open_common( psz_target, NULL, NULL );
> +}
> +
> +/**
> + * \brief Open a DVD device using dvdcss_stream_cb.
> + *
> + * \param p_stream a private handle used by p_stream_cb
> + * \param p_stream_cb a struct containing seek and read functions
> + * \return a handle to a dvdcss instance or NULL on error.
> + *
> + * \see dvdcss_open()
> + */
> +LIBDVDCSS_EXPORT dvdcss_t dvdcss_open_stream ( void *p_stream,
> +                                               dvdcss_stream_cb
> *p_stream_cb )
> +{
> +    return dvdcss_open_common( NULL, p_stream, p_stream_cb );
> +}
> +
> +static dvdcss_t dvdcss_open_common ( const char *psz_target, void
> *p_stream,
> +                                     dvdcss_stream_cb *p_stream_cb )
> +{
>      int i_ret;
>  
>      const char *psz_cache;
> @@ -423,6 +446,10 @@ LIBDVDCSS_EXPORT dvdcss_t dvdcss_open ( const char
> *psz_target )
>      const char *psz_raw_device = getenv( "DVDCSS_RAW_DEVICE" );
>  #endif
>  
> +    if( psz_target == NULL &&
> +      ( p_stream == NULL || p_stream_cb == NULL ) )
> +        return NULL;
> +
>      /* Allocate the library structure */
>      dvdcss_t dvdcss = malloc( sizeof( struct dvdcss_s ) );
>      if( dvdcss == NULL )
> @@ -440,6 +467,9 @@ LIBDVDCSS_EXPORT dvdcss_t dvdcss_open ( const char
> *psz_target )
>      dvdcss->i_method = DVDCSS_METHOD_KEY;
>      dvdcss->psz_cachefile[0] = '\0';
>  
> +    dvdcss->p_stream = p_stream;
> +    dvdcss->p_stream_cb = p_stream_cb;
> +
>      /* Set library verbosity from DVDCSS_VERBOSE environment variable.
>      */
>      set_verbosity( dvdcss );
>  
> diff --git a/src/libdvdcss.h b/src/libdvdcss.h
> index 4f1f4af..f2368fb 100644
> --- a/src/libdvdcss.h
> +++ b/src/libdvdcss.h
> @@ -72,6 +72,9 @@ struct dvdcss_s
>      int    i_readv_buf_size;
>  #endif /* WIN32 */
>  
> +    void                *p_stream;
> +    dvdcss_stream_cb    *p_stream_cb;
> +
>  #ifdef DVDCSS_RAW_OPEN
>      int    i_raw_fd;
>  #endif
> -- 
> 1.9.1
> 
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