Stop using SIGUSR1 for cancelling threads, use pthread_cancel and fri…

…ends instead, fix some memory leaks, add accurate ouput rate calculation to statistics, add "quit" verb to MPRIS and native d-bus interfaces. Probably still buggy.

audio.c

@@ -1,6 +1,7 @@
 /*
  * Audio driver handler. This file is part of Shairport.
  * Copyright (c) James Laird 2013
+ * Modifications (c) Mike Brady 2014 -- 2018
  * All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person

audio.h

@@ -22,7 +22,7 @@ typedef struct {
  void (*start)(int sample_rate, int sample_format);
 
  // block of samples
- void (*play)(void *buf, int samples);
+ int (*play)(void *buf, int samples);
  void (*stop)(void);
 
  // may be null if not implemented
@@ -33,6 +33,8 @@ typedef struct {
  // will change dynamically, so keep watching it. Implemented in ALSA only.
  // returns a negative error code if there's a problem
  int (*delay)(long *the_delay); // snd_pcm_sframes_t is a signed long
+ int (*rate_info)(uint64_t *elapsed_time,
+ uint64_t *frames_played); // use this to get the true rate of the DAC
 
  // may be NULL, in which case soft volume is applied
  void (*volume)(double vol);