code.delx.au - pulseaudio/blob - src/pulsecore/rtpoll.h

   1 #ifndef foopulsertpollhfoo
   2 #define foopulsertpollhfoo
   3
   4 /***
   5   This file is part of PulseAudio.
   6
   7   Copyright 2004-2006 Lennart Poettering
   8
   9   PulseAudio is free software; you can redistribute it and/or modify
  10   it under the terms of the GNU Lesser General Public License as
  11   published by the Free Software Foundation; either version 2.1 of the
  12   License, or (at your option) any later version.
  13
  14   PulseAudio is distributed in the hope that it will be useful, but
  15   WITHOUT ANY WARRANTY; without even the implied warranty of
  16   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  17   Lesser General Public License for more details.
  18
  19   You should have received a copy of the GNU Lesser General Public
  20   License along with PulseAudio; if not, write to the Free Software
  21   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  22   USA.
  23 ***/
  24
  25 #include <sys/types.h>
  26 #include <limits.h>
  27
  28 #include <pulse/sample.h>
  29 #include <pulsecore/asyncmsgq.h>
  30 #include <pulsecore/fdsem.h>
  31 #include <pulsecore/macro.h>
  32
  33 /* An implementation of a "real-time" poll loop. Basically, this is
  34  * yet another wrapper around poll(). However it has certain
  35  * advantages over pa_mainloop and suchlike:
  36  *
  37  * 1) It uses timer_create() and POSIX real time signals to guarantee
  38  * optimal high-resolution timing. Starting with Linux 2.6.21 hrtimers
  39  * are available, and since right now only nanosleep() and the POSIX
  40  * clock and timer interfaces have been ported to hrtimers (and not
  41  * ppoll/pselect!) we have to combine ppoll() with timer_create(). The
  42  * fact that POSIX timers and POSIX rt signals are used internally is
  43  * completely hidden.
  44  *
  45  * 2) It allows raw access to the pollfd data to users
  46  *
  47  * 3) It allows arbitrary functions to be run before entering the
  48  * actual poll() and after it.
  49  *
  50  * Only a single interval timer is supported..*/
  51
  52 typedef struct pa_rtpoll pa_rtpoll;
  53 typedef struct pa_rtpoll_item pa_rtpoll_item;
  54
  55 typedef enum pa_rtpoll_priority {
  56     PA_RTPOLL_EARLY  = -100,          /* For veeery important stuff, like handling control messages */
  57     PA_RTPOLL_NORMAL = 0,             /* For normal stuff */
  58     PA_RTPOLL_LATE   = +100,          /* For housekeeping */
  59     PA_RTPOLL_NEVER  = INT_MAX,       /* For stuff that doesn't register any callbacks, but only fds to listen on */
  60 } pa_rtpoll_priority_t;
  61
  62 pa_rtpoll *pa_rtpoll_new(void);
  63 void pa_rtpoll_free(pa_rtpoll *p);
  64
  65 /* Install the rtpoll in the current thread */
  66 void pa_rtpoll_install(pa_rtpoll *p);
  67
  68 /* Sleep on the rtpoll until the time event, or any of the fd events
  69  * is triggered. If "wait" is 0 we don't sleep but only update the
  70  * struct pollfd. Returns negative on error, positive if the loop
  71  * should continue to run, 0 when the loop should be terminated
  72  * cleanly. */
  73 int pa_rtpoll_run(pa_rtpoll *f, pa_bool_t wait);
  74
  75 void pa_rtpoll_set_timer_absolute(pa_rtpoll *p, pa_usec_t usec);
  76 void pa_rtpoll_set_timer_relative(pa_rtpoll *p, pa_usec_t usec);
  77 void pa_rtpoll_set_timer_disabled(pa_rtpoll *p);
  78
  79 /* A new fd wakeup item for pa_rtpoll */
  80 pa_rtpoll_item *pa_rtpoll_item_new(pa_rtpoll *p, pa_rtpoll_priority_t prio, unsigned n_fds);
  81 void pa_rtpoll_item_free(pa_rtpoll_item *i);
  82
  83 /* Please note that this pointer might change on every call and when
  84  * pa_rtpoll_run() is called. Hence: call this immediately before
  85  * using the pointer and don't save the result anywhere */
  86 struct pollfd *pa_rtpoll_item_get_pollfd(pa_rtpoll_item *i, unsigned *n_fds);
  87
  88 /* Set the callback that shall be called when there's time to do some work: If the
  89  * callback returns a value > 0, the poll is skipped and the next
  90  * iteraton of the loop will start immediately. */
  91 void pa_rtpoll_item_set_work_callback(pa_rtpoll_item *i, int (*work_cb)(pa_rtpoll_item *i));
  92
  93 /* Set the callback that shall be called immediately before entering
  94  * the sleeping poll: If the callback returns a value > 0, the poll is
  95  * skipped and the next iteraton of the loop will start
  96  * immediately.. */
  97 void pa_rtpoll_item_set_before_callback(pa_rtpoll_item *i, int (*before_cb)(pa_rtpoll_item *i));
  98
  99 /* Set the callback that shall be called immediately after having
 100  * entered the sleeping poll */
 101 void pa_rtpoll_item_set_after_callback(pa_rtpoll_item *i, void (*after_cb)(pa_rtpoll_item *i));
 102
 103 void pa_rtpoll_item_set_userdata(pa_rtpoll_item *i, void *userdata);
 104 void* pa_rtpoll_item_get_userdata(pa_rtpoll_item *i);
 105
 106 pa_rtpoll_item *pa_rtpoll_item_new_fdsem(pa_rtpoll *p, pa_rtpoll_priority_t prio, pa_fdsem *s);
 107 pa_rtpoll_item *pa_rtpoll_item_new_asyncmsgq_read(pa_rtpoll *p, pa_rtpoll_priority_t prio, pa_asyncmsgq *q);
 108 pa_rtpoll_item *pa_rtpoll_item_new_asyncmsgq_write(pa_rtpoll *p, pa_rtpoll_priority_t prio, pa_asyncmsgq *q);
 109
 110 /* Requests the loop to exit. Will cause the next iteration of
 111  * pa_rtpoll_run() to return 0 */
 112 void pa_rtpoll_quit(pa_rtpoll *p);
 113
 114 #endif