src/modules/module-always-sink.c

   1 /***
   2     This file is part of PulseAudio.
   3
   4     Copyright 2008 Colin Guthrie
   5
   6     PulseAudio is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU Lesser General Public License as published
   8     by the Free Software Foundation; either version 2 of the License,
   9     or (at your option) any later version.
  10
  11     PulseAudio is distributed in the hope that it will be useful, but
  12     WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14     General Public License for more details.
  15
  16     You should have received a copy of the GNU Lesser General Public License
  17     along with PulseAudio; if not, write to the Free Software
  18     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  19     USA.
  20 ***/
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <pulse/xmalloc.h>
  27
  28 #include <pulsecore/core.h>
  29 #include <pulsecore/sink-input.h>
  30 #include <pulsecore/modargs.h>
  31 #include <pulsecore/log.h>
  32 #include <pulsecore/namereg.h>
  33 #include <pulsecore/core-util.h>
  34
  35 #include "module-always-sink-symdef.h"
  36
  37 PA_MODULE_AUTHOR("Colin Guthrie");
  38 PA_MODULE_DESCRIPTION("Always keeps at least one sink loaded even if it's a null one");
  39 PA_MODULE_VERSION(PACKAGE_VERSION);
  40 PA_MODULE_LOAD_ONCE(TRUE);
  41 PA_MODULE_USAGE(
  42         "sink_name=<name of sink>");
  43
  44 #define DEFAULT_SINK_NAME "auto_null"
  45
  46 static const char* const valid_modargs[] = {
  47     "sink_name",
  48     NULL,
  49 };
  50
  51 struct userdata {
  52     pa_hook_slot *put_slot, *unlink_slot;
  53     pa_module* null_module;
  54     pa_bool_t ignore;
  55     char *sink_name;
  56 };
  57
  58 static void load_null_sink_if_needed(pa_core *c, pa_sink *sink, struct userdata* u) {
  59     pa_sink *target;
  60     uint32_t idx;
  61     char *t;
  62
  63     pa_assert(c);
  64     pa_assert(u);
  65     pa_assert(!u->null_module);
  66
  67     /* Loop through all sinks and check to see if we have *any*
  68      * sinks. Ignore the sink passed in (if it's not null) */
  69     for (target = pa_idxset_first(c->sinks, &idx); target; target = pa_idxset_next(c->sinks, &idx))
  70         if (!sink || target != sink)
  71             break;
  72
  73     if (target)
  74         return;
  75
  76     pa_log_debug("Autoloading null-sink as no other sinks detected.");
  77
  78     u->ignore = TRUE;
  79
  80     t = pa_sprintf_malloc("sink_name=%s", u->sink_name);
  81     u->null_module = pa_module_load(c, "module-null-sink", t);
  82     pa_xfree(t);
  83
  84     u->ignore = FALSE;
  85
  86     if (!u->null_module)
  87         pa_log_warn("Unable to load module-null-sink");
  88 }
  89
  90 static pa_hook_result_t put_hook_callback(pa_core *c, pa_sink *sink, void* userdata) {
  91     struct userdata *u = userdata;
  92
  93     pa_assert(c);
  94     pa_assert(sink);
  95     pa_assert(u);
  96
  97     /* This is us detecting ourselves on load... just ignore this. */
  98     if (u->ignore)
  99         return PA_HOOK_OK;
 100
 101     /* Auto-loaded null-sink not active, so ignoring newly detected sink. */
 102     if (!u->null_module)
 103         return PA_HOOK_OK;
 104
 105     /* This is us detecting ourselves on load in a different way... just ignore this too. */
 106     if (sink->module == u->null_module)
 107         return PA_HOOK_OK;
 108
 109     pa_log_info("A new sink has been discovered. Unloading null-sink.");
 110
 111     pa_module_unload_request(u->null_module, TRUE);
 112     u->null_module = NULL;
 113
 114     return PA_HOOK_OK;
 115 }
 116
 117 static pa_hook_result_t unlink_hook_callback(pa_core *c, pa_sink *sink, void* userdata) {
 118     struct userdata *u = userdata;
 119
 120     pa_assert(c);
 121     pa_assert(sink);
 122     pa_assert(u);
 123
 124     /* First check to see if it's our own null-sink that's been removed... */
 125     if (u->null_module && sink->module == u->null_module) {
 126         pa_log_debug("Autoloaded null-sink removed");
 127         u->null_module = NULL;
 128         return PA_HOOK_OK;
 129     }
 130
 131     load_null_sink_if_needed(c, sink, u);
 132
 133     return PA_HOOK_OK;
 134 }
 135
 136 int pa__init(pa_module*m) {
 137     pa_modargs *ma = NULL;
 138     struct userdata *u;
 139
 140     pa_assert(m);
 141
 142     if (!(ma = pa_modargs_new(m->argument, valid_modargs))) {
 143         pa_log("Failed to parse module arguments");
 144         return -1;
 145     }
 146
 147     m->userdata = u = pa_xnew(struct userdata, 1);
 148     u->sink_name = pa_xstrdup(pa_modargs_get_value(ma, "sink_name", DEFAULT_SINK_NAME));
 149     u->put_slot = pa_hook_connect(&m->core->hooks[PA_CORE_HOOK_SINK_PUT], PA_HOOK_LATE, (pa_hook_cb_t) put_hook_callback, u);
 150     u->unlink_slot = pa_hook_connect(&m->core->hooks[PA_CORE_HOOK_SINK_UNLINK], PA_HOOK_EARLY, (pa_hook_cb_t) unlink_hook_callback, u);
 151     u->null_module = NULL;
 152     u->ignore = FALSE;
 153
 154     pa_modargs_free(ma);
 155
 156     load_null_sink_if_needed(m->core, NULL, u);
 157
 158     return 0;
 159 }
 160
 161 void pa__done(pa_module*m) {
 162     struct userdata *u;
 163
 164     pa_assert(m);
 165
 166     if (!(u = m->userdata))
 167         return;
 168
 169     if (u->put_slot)
 170         pa_hook_slot_free(u->put_slot);
 171     if (u->unlink_slot)
 172         pa_hook_slot_free(u->unlink_slot);
 173     if (u->null_module)
 174         pa_module_unload_request(u->null_module, TRUE);
 175
 176     pa_xfree(u->sink_name);
 177     pa_xfree(u);
 178 }