filter-heuristics: New module that applies some basic heuristics regarding filters.

At present the only heuristic is one to apply the echo-cancel filter
when dealing with phone streams.

src/Makefile.am

@@ -1053,7 +1053,8 @@ modlibexec_LTLIBRARIES += \
 		module-virtual-sink.la \
 		module-virtual-source.la \
 		module-switch-on-connect.la \
-		module-filter-apply.la
+		module-filter-apply.la \
+		module-filter-heuristics.la
 
 # See comment at librtp.la above
 if !OS_IS_WIN32
@@ -1342,7 +1343,8 @@ SYMDEF_FILES = \
 		module-virtual-sink-symdef.h \
 		module-virtual-source-symdef.h \
 		module-switch-on-connect-symdef.h \
-		module-filter-apply-symdef.h
+		module-filter-apply-symdef.h \
+		module-filter-heuristics-symdef.h
 
 EXTRA_DIST += $(SYMDEF_FILES)
 BUILT_SOURCES += $(SYMDEF_FILES) builddirs
@@ -1492,6 +1494,10 @@ 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_filter_heuristics_la_SOURCES = modules/module-filter-heuristics.c
+module_filter_heuristics_la_LDFLAGS = $(MODULE_LDFLAGS)
+module_filter_heuristics_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-heuristics.c

@@ -0,0 +1,117 @@
+/***
+  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 <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-heuristics-symdef.h"
+
+#define PA_PROP_FILTER_WANT "filter.want"
+#define PA_PROP_FILTER_SUPPRESS "filter.suppress"
+
+
+PA_MODULE_AUTHOR("Colin Guthrie");
+PA_MODULE_DESCRIPTION("Detect when various filters are desirable");
+PA_MODULE_VERSION(PACKAGE_VERSION);
+PA_MODULE_LOAD_ONCE(TRUE);
+
+static const char* const valid_modargs[] = {
+    NULL
+};
+
+struct userdata {
+    pa_core *core;
+    pa_hook_slot
+        *sink_input_put_slot;
+};
+
+static pa_hook_result_t sink_input_put_cb(pa_core *core, pa_sink_input *i, struct userdata *u) {
+    const char *role;
+
+    pa_core_assert_ref(core);
+    pa_sink_input_assert_ref(i);
+    pa_assert(u);
+
+    /* If the stream already specifies what it wants, then let it be. */
+    if (pa_proplist_gets(i->proplist, PA_PROP_FILTER_WANT))
+        return PA_HOOK_OK;
+
+    if ((role = pa_proplist_gets(i->proplist, PA_PROP_MEDIA_ROLE)) && pa_streq(role, "phone"))
+        pa_proplist_sets(i->proplist, PA_PROP_FILTER_WANT, "echo-cancel");
+
+    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_xnew(struct userdata, 1);
+
+    u->core = m->core;
+
+    u->sink_input_put_slot = pa_hook_connect(&m->core->hooks[PA_CORE_HOOK_SINK_INPUT_PUT], PA_HOOK_LATE-1, (pa_hook_cb_t) sink_input_put_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);
+
+    pa_xfree(u);
+
+}