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/***
This file is part of PulseAudio.
Copyright 2008 Colin Guthrie
Copyright 2017 Sebastian Dröge <sebastian@centricular.com>
PulseAudio is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation; either version 2.1 of the License,
or (at your option) any later version.
PulseAudio is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
***/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <pulse/xmalloc.h>
#include <pulsecore/core.h>
#include <pulsecore/core-util.h>
#include <pulsecore/i18n.h>
#include <pulsecore/source.h>
#include <pulsecore/modargs.h>
#include <pulsecore/log.h>
PA_MODULE_AUTHOR("Sebastian Dröge");
PA_MODULE_DESCRIPTION(_("Always keeps at least one source loaded even if it's a null one"));
PA_MODULE_VERSION(PACKAGE_VERSION);
PA_MODULE_LOAD_ONCE(true);
PA_MODULE_USAGE(
"source_name=<name of source>");
#define DEFAULT_SOURCE_NAME "auto_null"
static const char* const valid_modargs[] = {
"source_name",
NULL,
};
struct userdata {
uint32_t null_module;
bool ignore;
char *source_name;
};
static void load_null_source_if_needed(pa_core *c, pa_source *source, struct userdata* u) {
pa_source *target;
uint32_t idx;
char *t;
pa_module *m;
pa_assert(c);
pa_assert(u);
if (u->null_module != PA_INVALID_INDEX)
return; /* We've already got a null-source loaded */
/* Loop through all sources and check to see if we have *any*
* sources. Ignore the source passed in (if it's not null), and
* don't count filter or monitor sources. */
PA_IDXSET_FOREACH(target, c->sources, idx)
if (!source || ((target != source) && !pa_source_is_filter(target) && target->monitor_of == NULL))
break;
if (target)
return;
pa_log_debug("Autoloading null-source as no other sources detected.");
u->ignore = true;
t = pa_sprintf_malloc("source_name=%s", u->source_name);
pa_module_load(&m, c, "module-null-source", t);
u->null_module = m ? m->index : PA_INVALID_INDEX;
pa_xfree(t);
u->ignore = false;
if (!m)
pa_log_warn("Unable to load module-null-source");
}
static pa_hook_result_t put_hook_callback(pa_core *c, pa_source *source, void* userdata) {
struct userdata *u = userdata;
pa_assert(c);
pa_assert(source);
pa_assert(u);
/* This is us detecting ourselves on load... just ignore this. */
if (u->ignore)
return PA_HOOK_OK;
/* There's no point in doing anything if the core is shut down anyway */
if (c->state == PA_CORE_SHUTDOWN)
return PA_HOOK_OK;
/* Auto-loaded null-source not active, so ignoring newly detected source. */
if (u->null_module == PA_INVALID_INDEX)
return PA_HOOK_OK;
/* This is us detecting ourselves on load in a different way... just ignore this too. */
if (source->module && source->module->index == u->null_module)
return PA_HOOK_OK;
/* We don't count filter or monitor sources since they need a real source */
if (pa_source_is_filter(source) || source->monitor_of != NULL)
return PA_HOOK_OK;
pa_log_info("A new source has been discovered. Unloading null-source.");
pa_module_unload_request_by_index(c, u->null_module, true);
u->null_module = PA_INVALID_INDEX;
return PA_HOOK_OK;
}
static pa_hook_result_t unlink_hook_callback(pa_core *c, pa_source *source, void* userdata) {
struct userdata *u = userdata;
pa_assert(c);
pa_assert(source);
pa_assert(u);
/* First check to see if it's our own null-source that's been removed... */
if (u->null_module != PA_INVALID_INDEX && source->module && source->module->index == u->null_module) {
pa_log_debug("Autoloaded null-source removed");
u->null_module = PA_INVALID_INDEX;
return PA_HOOK_OK;
}
/* There's no point in doing anything if the core is shut down anyway */
if (c->state == PA_CORE_SHUTDOWN)
return PA_HOOK_OK;
load_null_source_if_needed(c, source, u);
return PA_HOOK_OK;
}
int pa__init(pa_module*m) {
pa_modargs *ma = NULL;
struct userdata *u;
pa_assert(m);
if (!(ma = pa_modargs_new(m->argument, valid_modargs))) {
pa_log("Failed to parse module arguments");
return -1;
}
m->userdata = u = pa_xnew(struct userdata, 1);
u->source_name = pa_xstrdup(pa_modargs_get_value(ma, "source_name", DEFAULT_SOURCE_NAME));
pa_module_hook_connect(m, &m->core->hooks[PA_CORE_HOOK_SOURCE_PUT], PA_HOOK_LATE, (pa_hook_cb_t) put_hook_callback, u);
pa_module_hook_connect(m, &m->core->hooks[PA_CORE_HOOK_SOURCE_UNLINK], PA_HOOK_EARLY, (pa_hook_cb_t) unlink_hook_callback, u);
u->null_module = PA_INVALID_INDEX;
u->ignore = false;
pa_modargs_free(ma);
load_null_source_if_needed(m->core, NULL, u);
return 0;
}
void pa__done(pa_module*m) {
struct userdata *u;
pa_assert(m);
if (!(u = m->userdata))
return;
if (u->null_module != PA_INVALID_INDEX && m->core->state != PA_CORE_SHUTDOWN)
pa_module_unload_request_by_index(m->core, u->null_module, true);
pa_xfree(u->source_name);
pa_xfree(u);
}
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