livehttp: try to comply draft 11 section 6.2.2 for how long to keep segments...

livehttp: try to comply draft 11 section 6.2.2 for how long to keep segments around in sliding window

modules/access_output/livehttp.c

@@ -166,6 +166,7 @@ typedef struct output_segment
     char *psz_uri;
     char *psz_key_uri;
     char *psz_duration;
+    float f_seglength;
     uint32_t i_segment_number;
     uint8_t aes_ivs[16];
 } output_segment_t;
@@ -488,6 +489,28 @@ static void destroySegment( output_segment_t *segment )
     free( segment );
 }
 
+/************************************************************************
+ * isFirstItemRemovable: Check for draft 11 section 6.2.2 
+ * check that the first item has been around outside playlist 
+ * segment->f_seglength + p_sys->i_seglen before it is removed.
+ ************************************************************************/
+static bool isFirstItemRemovable( sout_access_out_sys_t *p_sys, uint32_t i_firstseg, uint32_t i_index_offset )
+{
+    float duration = .0f;
+
+    /* Check that segment has been out of playlist for seglenght + p_sys->i_seglen amount
+     * We check this by calculating duration of the items that replaced first item in playlist
+     */
+    for(int index=0; index < i_index_offset; index++ )
+    {
+        output_segment_t *segment = vlc_array_item_at_index( p_sys->segments_t, p_sys->i_segment - i_firstseg + index );
+        duration += segment->f_seglength;
+    }
+    output_segment_t *first = vlc_array_item_at_index( p_sys->segments_t, 0 );
+
+    return duration >= (first->f_seglength + (float)p_sys->i_seglen);
+}
+
 /************************************************************************
  * updateIndexAndDel: If necessary, update index file & delete old segments
  ************************************************************************/
@@ -607,15 +630,22 @@ static int updateIndexAndDel( sout_access_out_t *p_access, sout_access_out_sys_t
     }
 
     // Then take care of deletion
-    while( p_sys->b_delsegs && p_sys->i_numsegs && ( (vlc_array_count( p_sys->segments_t ) ) > p_sys->i_numsegs ) )
+    // Try to follow pantos draft 11 section 6.2.2
+    while( p_sys->b_delsegs && p_sys->i_numsegs &&
+           isFirstItemRemovable( p_sys, i_firstseg, i_index_offset )
+         )
     {
          output_segment_t *segment = vlc_array_item_at_index( p_sys->segments_t, 0 );
+         msg_Dbg( p_access, "Removing segment number %d", segment->i_segment_number );
          vlc_array_remove( p_sys->segments_t, 0 );
+
          if ( segment->psz_filename )
          {
              vlc_unlink( segment->psz_filename );
          }
+
          destroySegment( segment );
+         i_index_offset -=1;
     }
 
 
@@ -656,6 +686,7 @@ static void closeCurrentSegment( sout_access_out_t *p_access, sout_access_out_sy
             msg_Err( p_access, "Couldn't set duration on closed segment");
             return;
         }
+        segment->f_seglength = p_sys->f_seglen;
 
         segment->i_segment_number = p_sys->i_segment;