src/decoder_internal.c

   1 /*
   2  * Copyright (C) 2003-2009 The Music Player Daemon Project
   3  * http://www.musicpd.org
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #include "decoder_internal.h"
  21 #include "decoder_control.h"
  22 #include "player_control.h"
  23 #include "pipe.h"
  24 #include "input_stream.h"
  25 #include "buffer.h"
  26 #include "chunk.h"
  27
  28 #include <assert.h>
  29
  30 /**
  31  * This is a wrapper for input_stream_buffer().  It assumes that the
  32  * decoder is currently locked, and temporarily unlocks it while
  33  * calling input_stream_buffer().  We shouldn't hold the lock during a
  34  * potentially blocking operation.
  35  */
  36 static int
  37 decoder_input_buffer(struct input_stream *is)
  38 {
  39         int ret;
  40
  41         decoder_unlock();
  42         ret = input_stream_buffer(is) > 0;
  43         decoder_lock();
  44
  45         return ret;
  46 }
  47
  48 /**
  49  * All chunks are full of decoded data; wait for the player to free
  50  * one.
  51  */
  52 static enum decoder_command
  53 need_chunks(struct input_stream *is, bool do_wait)
  54 {
  55         if (dc.command == DECODE_COMMAND_STOP ||
  56             dc.command == DECODE_COMMAND_SEEK)
  57                 return dc.command;
  58
  59         if ((is == NULL || decoder_input_buffer(is) <= 0) && do_wait) {
  60                 decoder_wait();
  61
  62                 decoder_unlock();
  63                 notify_signal(&pc.notify);
  64                 decoder_lock();
  65
  66                 return dc.command;
  67         }
  68
  69         return DECODE_COMMAND_NONE;
  70 }
  71
  72 struct music_chunk *
  73 decoder_get_chunk(struct decoder *decoder, struct input_stream *is)
  74 {
  75         enum decoder_command cmd;
  76
  77         assert(decoder != NULL);
  78
  79         if (decoder->chunk != NULL)
  80                 return decoder->chunk;
  81
  82         do {
  83                 decoder->chunk = music_buffer_allocate(dc.buffer);
  84                 if (decoder->chunk != NULL)
  85                         return decoder->chunk;
  86
  87                 decoder_lock();
  88                 cmd = need_chunks(is, true);
  89                 decoder_unlock();
  90         } while (cmd == DECODE_COMMAND_NONE);
  91
  92         return NULL;
  93 }
  94
  95 void
  96 decoder_flush_chunk(struct decoder *decoder)
  97 {
  98         assert(decoder != NULL);
  99         assert(decoder->chunk != NULL);
 100
 101         if (music_chunk_is_empty(decoder->chunk))
 102                 music_buffer_return(dc.buffer, decoder->chunk);
 103         else
 104                 music_pipe_push(dc.pipe, decoder->chunk);
 105
 106         decoder->chunk = NULL;
 107 }