filter-apply: New module to automatically load filter sinks (and move streams) based on sink-input property hints.

This module does not yet deal with modules that need matched inputs/outputs
(i.e. echo-cancel) but this will be added in due course.

src/Makefile.am

@@ -1052,7 +1052,8 @@ modlibexec_LTLIBRARIES += \
 		module-loopback.la \
 		module-virtual-sink.la \
 		module-virtual-source.la \
-		module-switch-on-connect.la
+		module-switch-on-connect.la \
+		module-filter-apply.la
 
 # See comment at librtp.la above
 if !OS_IS_WIN32
@@ -1340,7 +1341,8 @@ SYMDEF_FILES = \
 		module-loopback-symdef.h \
 		module-virtual-sink-symdef.h \
 		module-virtual-source-symdef.h \
-		module-switch-on-connect-symdef.h
+		module-switch-on-connect-symdef.h \
+		module-filter-apply-symdef.h
 
 EXTRA_DIST += $(SYMDEF_FILES)
 BUILT_SOURCES += $(SYMDEF_FILES) builddirs
@@ -1486,6 +1488,10 @@ module_switch_on_connect_la_SOURCES = modules/module-switch-on-connect.c
 module_switch_on_connect_la_LDFLAGS = $(MODULE_LDFLAGS)
 module_switch_on_connect_la_LIBADD = $(MODULE_LIBADD)
 
+module_filter_apply_la_SOURCES = modules/module-filter-apply.c
+module_filter_apply_la_LDFLAGS = $(MODULE_LDFLAGS)
+module_filter_apply_la_LIBADD = $(MODULE_LIBADD)
+
 module_remap_sink_la_SOURCES = modules/module-remap-sink.c
 module_remap_sink_la_LDFLAGS = $(MODULE_LDFLAGS)
 module_remap_sink_la_LIBADD = $(MODULE_LIBADD)

src/modules/module-filter-apply.c

@@ -0,0 +1,400 @@
+/***
+  This file is part of PulseAudio.
+
+  Copyright 2011 Colin Guthrie
+
+  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, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <pulse/timeval.h>
+#include <pulse/rtclock.h>
+
+#include <pulsecore/macro.h>
+#include <pulsecore/hashmap.h>
+#include <pulsecore/hook-list.h>
+#include <pulsecore/core.h>
+#include <pulsecore/core-util.h>
+#include <pulsecore/sink-input.h>
+#include <pulsecore/modargs.h>
+
+#include "module-filter-apply-symdef.h"
+
+#define PA_PROP_FILTER_WANT "filter.want"
+#define PA_PROP_FILTER_SUPPRESS "filter.suppress"
+
+
+PA_MODULE_AUTHOR("Colin Guthrie");
+PA_MODULE_DESCRIPTION("Load filter sinks automatically when needed");
+PA_MODULE_VERSION(PACKAGE_VERSION);
+PA_MODULE_LOAD_ONCE(TRUE);
+
+static const char* const valid_modargs[] = {
+    NULL
+};
+
+#define HOUSEKEEPING_INTERVAL (10 * PA_USEC_PER_SEC)
+
+struct filter {
+    char *name;
+    pa_sink* parent_sink;
+    uint32_t module_index;
+    pa_sink* sink;
+};
+
+struct userdata {
+    pa_core *core;
+    pa_hashmap *filters;
+    pa_hook_slot
+        *sink_input_put_slot,
+        *sink_input_proplist_slot,
+        *sink_input_unlink_slot,
+        *sink_unlink_slot;
+    pa_time_event *housekeeping_time_event;
+};
+
+static unsigned filter_hash(const void *p) {
+    const struct filter *f = p;
+
+    return
+        (unsigned) f->parent_sink->index +
+        pa_idxset_string_hash_func(f->name);
+}
+
+static int filter_compare(const void *a, const void *b) {
+    const struct filter *fa = a, *fb = b;
+    int r;
+
+    if (fa->parent_sink != fb->parent_sink)
+        return 1;
+    if ((r = strcmp(fa->name, fb->name)))
+        return r;
+
+    return 0;
+}
+
+static struct filter *filter_new(const char *name, pa_sink* parent_sink) {
+    struct filter *f;
+
+    f = pa_xnew(struct filter, 1);
+    f->name = pa_xstrdup(name);
+    pa_assert_se(f->parent_sink = parent_sink);
+    f->module_index = PA_INVALID_INDEX;
+    f->sink = NULL;
+    return f;
+}
+
+static void filter_free(struct filter *f) {
+    pa_assert(f);
+
+    pa_xfree(f->name);
+    pa_xfree(f);
+}
+
+static const char* should_filter(pa_sink_input *i) {
+    const char *want;
+
+    /* If the stream doesn't what any filter, then let it be. */
+    if ((want = pa_proplist_gets(i->proplist, PA_PROP_FILTER_WANT)) && !pa_streq(want, "")) {
+        const char* suppress = pa_proplist_gets(i->proplist, PA_PROP_FILTER_SUPPRESS);
+
+        if (!suppress || !pa_streq(suppress, want))
+            return want;
+    }
+
+    return NULL;
+}
+
+static void housekeeping_time_callback(pa_mainloop_api*a, pa_time_event* e, const struct timeval *t, void *userdata) {
+    struct userdata *u = userdata;
+    struct filter *filter;
+    void *state;
+
+    pa_assert(a);
+    pa_assert(e);
+    pa_assert(u);
+
+    pa_assert(e == u->housekeeping_time_event);
+    u->core->mainloop->time_free(u->housekeeping_time_event);
+    u->housekeeping_time_event = NULL;
+
+    PA_HASHMAP_FOREACH(filter, u->filters, state) {
+        if (filter->sink && pa_idxset_size(filter->sink->inputs) == 0) {
+            uint32_t idx;
+
+            pa_log_debug("Detected filter %s as no longer used on sink %s. Unloading.", filter->name, filter->sink->name);
+            idx = filter->module_index;
+            pa_hashmap_remove(u->filters, filter);
+            filter_free(filter);
+            pa_module_unload_request_by_index(u->core, idx, TRUE);
+        }
+    }
+
+    pa_log_info("Housekeeping Done.");
+}
+
+static void trigger_housekeeping(struct userdata *u) {
+    pa_assert(u);
+
+    if (u->housekeeping_time_event)
+        return;
+
+    u->housekeeping_time_event = pa_core_rttime_new(u->core, pa_rtclock_now() + HOUSEKEEPING_INTERVAL, housekeeping_time_callback, u);
+}
+
+static void move_input_for_filter(pa_sink_input *i, struct filter* filter, pa_bool_t restore) {
+    pa_sink *sink;
+
+    pa_assert(i);
+    pa_assert(filter);
+
+    pa_assert_se(sink = (restore ? filter->parent_sink : filter->sink));
+
+    if (pa_sink_input_move_to(i, sink, FALSE) < 0)
+        pa_log_info("Failed to move sink input %u \"%s\" to <%s>.", i->index,
+                    pa_strnull(pa_proplist_gets(i->proplist, PA_PROP_APPLICATION_NAME)), sink->name);
+    else
+        pa_log_info("Sucessfully moved sink input %u \"%s\" to <%s>.", i->index,
+                    pa_strnull(pa_proplist_gets(i->proplist, PA_PROP_APPLICATION_NAME)), sink->name);
+}
+
+static pa_hook_result_t process(struct userdata *u, pa_sink_input *i) {
+    const char *want;
+    pa_bool_t done_something = FALSE;
+
+    pa_assert(u);
+    pa_sink_input_assert_ref(i);
+
+    /* If there is no sink yet, we can't do much */
+    if (!i->sink)
+        return PA_HOOK_OK;
+
+    /* If the stream doesn't what any filter, then let it be. */
+    if ((want = should_filter(i))) {
+        char *module_name;
+        struct filter *fltr, *filter;
+
+        /* We need to ensure the SI is playing on a sink of this type
+         * attached to the sink it's "officially" playing on */
+
+        if (!i->sink->module)
+            return PA_HOOK_OK;
+
+        module_name = pa_sprintf_malloc("module-%s", want);
+        if (pa_streq(i->sink->module->name, module_name)) {
+            pa_log_debug("Stream appears to be playing on an appropriate sink already. Ignoring.");
+            pa_xfree(module_name);
+            return PA_HOOK_OK;
+        }
+
+        fltr = filter_new(want, i->sink);
+
+        if (!(filter = pa_hashmap_get(u->filters, fltr))) {
+            char *args;
+            pa_module *m;
+
+            args = pa_sprintf_malloc("sink_master=%s", i->sink->name);
+            pa_log_debug("Loading %s with arguments '%s'", module_name, args);
+
+            if ((m = pa_module_load(u->core, module_name, args))) {
+                uint32_t idx;
+                pa_sink *sink;
+
+                fltr->module_index = m->index;
+                /* We cannot use the SINK_PUT hook here to detect our sink as it'll
+                 * be called during the module load so we wont yet have put the filter
+                 * in our hashmap to compare... so we have to search for it */
+                PA_IDXSET_FOREACH(sink, u->core->sinks, idx) {
+                    if (sink->module == m) {
+                        fltr->sink = sink;
+                        break;
+                    }
+                }
+                pa_hashmap_put(u->filters, fltr, fltr);
+                filter = fltr;
+                fltr = NULL;
+                done_something = TRUE;
+            }
+            pa_xfree(args);
+        }
+        pa_xfree(fltr);
+
+        if (!filter) {
+            pa_log("Unable to load %s for sink <%s>", module_name, i->sink->name);
+            pa_xfree(module_name);
+            return PA_HOOK_OK;
+        }
+        pa_xfree(module_name);
+
+        if (filter->sink) {
+            /* We can move the sink_input now as the know the destination.
+             * If this isn't true, we will do it later when the sink appears. */
+            move_input_for_filter(i, filter, FALSE);
+            done_something = TRUE;
+        }
+    } else {
+        void *state;
+        struct filter *filter = NULL;
+
+        /* We do not want to filter... but are we already filtered?
+         * This can happen if an input's proplist changes */
+        PA_HASHMAP_FOREACH(filter, u->filters, state) {
+            if (i->sink == filter->sink) {
+                move_input_for_filter(i, filter, TRUE);
+                done_something = TRUE;
+                break;
+            }
+        }
+    }
+
+    if (done_something)
+        trigger_housekeeping(u);
+
+    return PA_HOOK_OK;
+}
+
+static pa_hook_result_t sink_input_put_cb(pa_core *core, pa_sink_input *i, struct userdata *u) {
+    pa_core_assert_ref(core);
+    pa_sink_input_assert_ref(i);
+
+    return process(u, i);
+}
+
+static pa_hook_result_t sink_input_proplist_cb(pa_core *core, pa_sink_input *i, struct userdata *u) {
+    pa_core_assert_ref(core);
+    pa_sink_input_assert_ref(i);
+
+    return process(u, i);
+}
+
+static pa_hook_result_t sink_input_unlink_cb(pa_core *core, pa_sink_input *i, struct userdata *u) {
+    pa_core_assert_ref(core);
+    pa_sink_input_assert_ref(i);
+
+    pa_assert(u);
+
+    if (pa_hashmap_size(u->filters) > 0)
+        trigger_housekeeping(u);
+
+    return PA_HOOK_OK;
+}
+
+static pa_hook_result_t sink_unlink_cb(pa_core *core, pa_sink *sink, struct userdata *u) {
+    void *state;
+    struct filter *filter = NULL;
+
+    pa_core_assert_ref(core);
+    pa_sink_assert_ref(sink);
+    pa_assert(u);
+
+    /* If either the parent or the sink we've loaded disappears,
+     * we should remove it from our hashmap */
+    PA_HASHMAP_FOREACH(filter, u->filters, state) {
+        if (filter->parent_sink == sink || filter->sink == sink) {
+            uint32_t idx;
+
+            /* Attempt to rescue any streams to the parent sink as this is likely
+             * the best course of action (as opposed to a generic rescue via
+             * module-rescue-streams */
+            if (filter->sink == sink) {
+                pa_sink_input *i;
+
+                PA_IDXSET_FOREACH(i, sink->inputs, idx)
+                    move_input_for_filter(i, filter, TRUE);
+            }
+
+            idx = filter->module_index;
+            pa_hashmap_remove(u->filters, filter);
+            filter_free(filter);
+            pa_module_unload_request_by_index(u->core, idx, TRUE);
+        }
+    }
+
+    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");
+        goto fail;
+    }
+
+    m->userdata = u = pa_xnew0(struct userdata, 1);
+
+    u->core = m->core;
+
+    u->filters = pa_hashmap_new(filter_hash, filter_compare);
+
+    u->sink_input_put_slot = pa_hook_connect(&m->core->hooks[PA_CORE_HOOK_SINK_INPUT_PUT], PA_HOOK_LATE, (pa_hook_cb_t) sink_input_put_cb, u);
+    u->sink_input_proplist_slot = pa_hook_connect(&m->core->hooks[PA_CORE_HOOK_SINK_INPUT_PROPLIST_CHANGED], PA_HOOK_LATE, (pa_hook_cb_t) sink_input_proplist_cb, u);
+    u->sink_input_unlink_slot = pa_hook_connect(&m->core->hooks[PA_CORE_HOOK_SINK_INPUT_UNLINK], PA_HOOK_LATE, (pa_hook_cb_t) sink_input_unlink_cb, u);
+    u->sink_unlink_slot = pa_hook_connect(&m->core->hooks[PA_CORE_HOOK_SINK_UNLINK], PA_HOOK_LATE, (pa_hook_cb_t) sink_unlink_cb, u);
+
+    pa_modargs_free(ma);
+
+    return 0;
+
+fail:
+    pa__done(m);
+
+    if (ma)
+        pa_modargs_free(ma);
+
+    return -1;
+}
+
+void pa__done(pa_module *m) {
+    struct userdata* u;
+
+    pa_assert(m);
+
+    if (!(u = m->userdata))
+        return;
+
+    if (u->sink_input_put_slot)
+        pa_hook_slot_free(u->sink_input_put_slot);
+    if (u->sink_input_proplist_slot)
+        pa_hook_slot_free(u->sink_input_proplist_slot);
+    if (u->sink_input_unlink_slot)
+        pa_hook_slot_free(u->sink_input_unlink_slot);
+    if (u->sink_unlink_slot)
+        pa_hook_slot_free(u->sink_unlink_slot);
+
+    if (u->housekeeping_time_event)
+        u->core->mainloop->time_free(u->housekeeping_time_event);
+
+    if (u->filters) {
+        struct filter *f;
+
+        while ((f = pa_hashmap_steal_first(u->filters))) {
+            pa_module_unload_request_by_index(u->core, f->module_index, TRUE);
+            filter_free(f);
+        }
+
+        pa_hashmap_free(u->filters, NULL, NULL);
+    }
+
+    pa_xfree(u);
+}