modules/stream_filter/accesstweaks.c

   1 /*****************************************************************************
   2  * accesstweaks.c Access controls tweaking stream filter
   3  *****************************************************************************
   4  * Copyright (C) 2015 VideoLAN Authors
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU Lesser General Public License as published by
   8  * the Free Software Foundation; either version 2.1 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  19  *****************************************************************************/
  20
  21 /*****************************************************************************
  22  * Preamble
  23  *****************************************************************************/
  24 #ifdef HAVE_CONFIG_H
  25 # include "config.h"
  26 #endif
  27
  28 #include <vlc_common.h>
  29 #include <vlc_plugin.h>
  30 #include <vlc_stream.h>
  31 #include <assert.h>
  32
  33 static int  Open(vlc_object_t *);
  34
  35 vlc_module_begin ()
  36     set_shortname("accesstweaks")
  37     set_category (CAT_INPUT)
  38     set_subcategory (SUBCAT_INPUT_STREAM_FILTER)
  39     set_capability ("stream_filter", 301)
  40     /* Developers only module, no translation please */
  41     set_description ("Access controls tweaking")
  42     set_callbacks(Open, NULL)
  43
  44     add_bool("seek", true, "Expose seeking capability", NULL, false)
  45         change_volatile ()
  46     add_bool("fastseek", true, "Expose fast-seeking capability", NULL, false)
  47         change_volatile ()
  48     add_bool("stream-size", true, "Expose stream size if known", NULL, false)
  49         change_volatile()
  50     add_shortcut("tweaks")
  51 vlc_module_end ()
  52
  53 struct stream_sys_t
  54 {
  55     bool b_seek;
  56     bool b_fastseek;
  57     bool b_size;
  58 };
  59
  60 /**
  61  *
  62  */
  63 static int Control( stream_t *p_stream, int i_query, va_list args )
  64 {
  65     stream_sys_t *p_sys = p_stream->p_sys;
  66
  67     switch( i_query )
  68     {
  69     case STREAM_CAN_FASTSEEK:
  70         if( !p_sys->b_fastseek || !p_sys->b_seek )
  71         {
  72             *va_arg( args, bool* ) = false;
  73             return VLC_SUCCESS;
  74         }
  75         break;
  76     case STREAM_CAN_SEEK:
  77         if( !p_sys->b_seek )
  78         {
  79             *va_arg( args, bool* ) = false;
  80             return VLC_SUCCESS;
  81         }
  82         break;
  83     case STREAM_GET_SIZE:
  84         if (!p_sys->b_size)
  85             return VLC_EGENERIC;
  86         break;
  87     default:
  88         break;
  89     }
  90
  91     return vlc_stream_vaControl( p_stream->s, i_query, args );
  92 }
  93
  94 static ssize_t Read( stream_t *s, void *buffer, size_t i_read )
  95 {
  96     return vlc_stream_Read( s->s, buffer, i_read );
  97 }
  98
  99 static int Seek( stream_t *s, uint64_t offset )
 100 {
 101     stream_sys_t *p_sys = s->p_sys;
 102
 103     assert( p_sys->b_seek );
 104     return vlc_stream_Seek( s->s, offset );
 105 }
 106
 107 static int Open( vlc_object_t *p_object )
 108 {
 109     stream_t *p_stream = (stream_t *) p_object;
 110     stream_sys_t *p_sys = vlc_obj_malloc(p_object, sizeof (*p_sys));
 111     if (unlikely(p_sys == NULL))
 112         return VLC_ENOMEM;
 113
 114     uint64_t size;
 115     bool b;
 116     bool used = false;
 117
 118     p_sys->b_seek = var_InheritBool(p_stream, "seek");
 119     p_sys->b_size = var_InheritBool(p_stream, "stream-size");
 120
 121     if (!p_sys->b_seek)
 122     {
 123         if (vlc_stream_Control(p_stream->s, STREAM_CAN_SEEK, &b) == 0)
 124             used = b;
 125
 126         p_sys->b_fastseek = false;
 127     }
 128     else
 129     {
 130         p_sys->b_fastseek = var_InheritBool(p_stream, "fastseek");
 131         if (!p_sys->b_fastseek
 132          && vlc_stream_Control(p_stream->s, STREAM_CAN_FASTSEEK,
 133                                &b) == 0)
 134             used = b;
 135     }
 136
 137     if (!p_sys->b_size && vlc_stream_GetSize(p_stream->s, &size) == 0)
 138         used = true;
 139
 140     if (!used) /* Nothing to do: skip this filter */
 141         return VLC_EGENERIC;
 142
 143     p_stream->p_sys = p_sys;
 144     p_stream->pf_read = Read;
 145     p_stream->pf_seek = p_sys->b_seek ? Seek : NULL;
 146     p_stream->pf_control = Control;
 147
 148     return VLC_SUCCESS;
 149 }