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

   1 #ifndef foopulseasyncqhfoo
   2 #define foopulseasyncqhfoo
   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 <pulse/def.h>
  27 #include <pulsecore/macro.h>
  28
  29 /* A simple, asynchronous, lock-free (if requested also wait-free)
  30  * queue. Not multiple-reader/multiple-writer safe. If that is
  31  * required both sides can be protected by a mutex each. --- Which is
  32  * not a bad thing in most cases, since this queue is intended for
  33  * communication between a normal thread and a single real-time
  34  * thread. Only the real-time side needs to be lock-free/wait-free.
  35  *
  36  * If the queue is full and another entry shall be pushed, or when the
  37  * queue is empty and another entry shall be popped and the "wait"
  38  * argument is non-zero, the queue will block on a UNIX FIFO object --
  39  * that will probably require locking on the kernel side -- which
  40  * however is probably not problematic, because we do it only on
  41  * starvation or overload in which case we have to block anyway.  */
  42
  43 typedef struct pa_asyncq pa_asyncq;
  44
  45 pa_asyncq* pa_asyncq_new(unsigned size);
  46 void pa_asyncq_free(pa_asyncq* q, pa_free_cb_t free_cb);
  47
  48 void* pa_asyncq_pop(pa_asyncq *q, bool wait);
  49 int pa_asyncq_push(pa_asyncq *q, void *p, bool wait);
  50
  51 /* Similar to pa_asyncq_push(), but if the queue is full, postpone the
  52  * appending of the item locally and delay until
  53  * pa_asyncq_before_poll_post() is called. */
  54 void pa_asyncq_post(pa_asyncq*l, void *p);
  55
  56 /* For the reading side */
  57 int pa_asyncq_read_fd(pa_asyncq *q);
  58 int pa_asyncq_read_before_poll(pa_asyncq *a);
  59 void pa_asyncq_read_after_poll(pa_asyncq *a);
  60
  61 /* For the writing side */
  62 int pa_asyncq_write_fd(pa_asyncq *q);
  63 void pa_asyncq_write_before_poll(pa_asyncq *a);
  64 void pa_asyncq_write_after_poll(pa_asyncq *a);
  65
  66 #endif