pulse-server: add gsettings module

Uses a thread to monitor gsettings data. Loads and unload modules
based on gsettings.

This makes paprefs work.

meson.build

@@ -301,6 +301,9 @@ summary({'GLib-2.0 (Flatpak support)': glib2_dep.found()}, bool_yn: true, sectio
 flatpak_support = glib2_dep.found()
 cdata.set('HAVE_GLIB2', flatpak_support)
 
+gio_dep = dependency('gio-2.0', version : '>= 2.26.0', required : get_option('gsettings'))
+summary({'GIO (GSettings)': gio_dep.found()}, bool_yn: true, section: 'Misc dependencies')
+
 gst_option = get_option('gstreamer')
 gst_deps_def = {
   'glib-2.0': {'version': '>=2.32.0'},

meson_options.txt

@@ -269,3 +269,7 @@ option('readline',
        description: 'Enable code that depends on libreadline',
        type: 'feature',
        value: 'auto')
+option('gsettings',
+       description: 'Enable code that depends on gsettings',
+       type: 'feature',
+       value: 'auto')

src/modules/meson.build

@@ -289,6 +289,14 @@ if avahi_dep.found()
   cdata.set('HAVE_AVAHI', true)
 endif
 
+if gio_dep.found()
+  pipewire_module_protocol_pulse_sources += [
+    'module-protocol-pulse/modules/module-gsettings.c',
+  ]
+  pipewire_module_protocol_pulse_deps += gio_dep
+  cdata.set('HAVE_GIO', true)
+endif
+
 if flatpak_support
   pipewire_module_protocol_pulse_deps += glib2_dep
 endif

src/modules/module-protocol-pulse/modules/module-gsettings.c

@@ -0,0 +1,298 @@
+/* PipeWire
+ *
+ * Copyright © 2022 Wim Taymans <wim.taymans@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <gio/gio.h>
+#include <glib.h>
+
+#include <spa/debug/mem.h>
+#include <pipewire/pipewire.h>
+#include <pipewire/thread.h>
+
+#include "../module.h"
+
+#define NAME "gsettings"
+
+PW_LOG_TOPIC_STATIC(mod_topic, "mod." NAME);
+#define PW_LOG_TOPIC_DEFAULT mod_topic
+
+#define PA_GSETTINGS_MODULE_GROUP_SCHEMA "org.freedesktop.pulseaudio.module-group"
+#define PA_GSETTINGS_MODULE_GROUPS_SCHEMA "org.freedesktop.pulseaudio.module-groups"
+#define PA_GSETTINGS_MODULE_GROUPS_PATH "/org/freedesktop/pulseaudio/module-groups/"
+
+#define MAX_MODULES	10
+
+struct module_gsettings_data {
+	struct module *module;
+
+	GMainContext *context;
+	GMainLoop *loop;
+	struct spa_thread *thr;
+
+	GSettings *settings;
+	gchar **group_names;
+
+	struct spa_list groups;
+};
+
+struct group {
+	struct spa_list link;
+	char *name;
+	struct module *module;
+	struct spa_hook module_listener;
+};
+
+struct info {
+	bool enabled;
+	char *name;
+	char *module[MAX_MODULES];
+	char *args[MAX_MODULES];
+};
+
+static void clean_info(const struct info *info)
+{
+	int i;
+	for (i = 0; i < MAX_MODULES; i++) {
+		g_free(info->module[i]);
+		g_free(info->args[i]);
+	}
+	g_free(info->name);
+}
+
+static void unload_module(struct module_gsettings_data *d, struct group *g)
+{
+	spa_list_remove(&g->link);
+	g_free(g->name);
+	if (g->module)
+		module_unload(g->module);
+	free(g);
+}
+
+static void unload_group(struct module_gsettings_data *d, const char *name)
+{
+	struct group *g, *t;
+	spa_list_for_each_safe(g, t, &d->groups, link) {
+		if (spa_streq(g->name, name))
+			unload_module(d, g);
+	}
+}
+static void module_destroy(void *data)
+{
+	struct group *g = data;
+	if (g->module) {
+		spa_hook_remove(&g->module_listener);
+		g->module = NULL;
+	}
+}
+
+static const struct module_events module_gsettings_events = {
+	VERSION_MODULE_EVENTS,
+	.destroy = module_destroy
+};
+
+static int load_group(struct module_gsettings_data *d, const struct info *info)
+{
+	struct group *g;
+	int i, res;
+
+	for (i = 0; i < MAX_MODULES; i++) {
+		if (info->module[i] == NULL || strlen(info->module[i]) <= 0)
+			break;
+
+		g = calloc(1, sizeof(struct group));
+		if (g == NULL)
+			return -errno;
+
+		g->name = strdup(info->name);
+		g->module = module_create(d->module->impl, info->module[i], info->args[i]);
+		if (g->module == NULL) {
+			pw_log_info("can't create module:%s args:%s: %m",
+					info->module[i], info->args[i]);
+		} else {
+			module_add_listener(g->module, &g->module_listener,
+					&module_gsettings_events, g);
+			if ((res = module_load(g->module)) < 0) {
+				pw_log_warn("can't load module:%s args:%s: %s",
+						info->module[i], info->args[i],
+						spa_strerror(res));
+			}
+		}
+		spa_list_append(&d->groups, &g->link);
+	}
+	return 0;
+}
+
+static int
+do_handle_info(struct spa_loop *loop,
+		bool async, uint32_t seq, const void *data, size_t size, void *user_data)
+{
+	struct module_gsettings_data *d = user_data;
+	const struct info *info = data;
+
+	unload_group(d, info->name);
+	if (info->enabled)
+		load_group(d, info);
+
+	clean_info(info);
+	return 0;
+}
+
+static void handle_module_group(struct module_gsettings_data *d, gchar *name)
+{
+	struct impl *impl = d->module->impl;
+	GSettings *settings;
+	gchar p[1024];
+	struct info info;
+	int i;
+
+	snprintf(p, sizeof(p), PA_GSETTINGS_MODULE_GROUPS_PATH"%s/", name);
+
+	settings = g_settings_new_with_path(PA_GSETTINGS_MODULE_GROUP_SCHEMA, p);
+	if (settings == NULL)
+		return;
+
+	spa_zero(info);
+	info.name = strdup(p);
+	info.enabled = g_settings_get_boolean(settings, "enabled");
+
+	for (i = 0; i < MAX_MODULES; i++) {
+		snprintf(p, sizeof(p), "name%d", i);
+		info.module[i] = g_settings_get_string(settings, p);
+
+		snprintf(p, sizeof(p), "args%i", i);
+		info.args[i] = g_settings_get_string(settings, p);
+	}
+	pw_loop_invoke(impl->loop, do_handle_info, 0,
+			&info, sizeof(info), false, d);
+
+	g_object_unref(G_OBJECT(settings));
+}
+
+static void module_group_callback(GSettings *settings, gchar *key, gpointer user_data)
+{
+	struct module_gsettings_data *d = g_object_get_data(G_OBJECT(settings), "module-data");
+	handle_module_group(d, user_data);
+}
+
+static void *do_loop(void *user_data)
+{
+	struct module_gsettings_data *d = user_data;
+
+	pw_log_info("enter");
+	g_main_context_push_thread_default(d->context);
+
+	d->loop = g_main_loop_new(d->context, FALSE);
+
+	g_main_loop_run(d->loop);
+
+	g_main_context_pop_thread_default(d->context);
+	g_main_loop_unref (d->loop);
+	d->loop = NULL;
+	pw_log_info("leave");
+
+	return NULL;
+}
+
+static int module_gsettings_load(struct module *module)
+{
+	struct module_gsettings_data *data = module->user_data;
+	gchar **name;
+
+	data->context = g_main_context_new();
+	g_main_context_push_thread_default(data->context);
+
+	data->settings = g_settings_new(PA_GSETTINGS_MODULE_GROUPS_SCHEMA);
+	if (data->settings == NULL)
+		return -EIO;
+
+	data->group_names = g_settings_list_children(data->settings);
+
+	for (name = data->group_names; *name; name++) {
+		GSettings *child = g_settings_get_child(data->settings, *name);
+		/* The child may have been removed between the
+		 * g_settings_list_children() and g_settings_get_child() calls. */
+		if (child == NULL)
+			continue;
+
+		g_object_set_data(G_OBJECT(child), "module-data", data);
+		g_signal_connect(child, "changed", (GCallback) module_group_callback, *name);
+		handle_module_group(data, *name);
+	}
+	g_main_context_pop_thread_default(data->context);
+
+	data->thr = pw_thread_utils_create(NULL, do_loop, data);
+	return 0;
+}
+
+static gboolean
+do_stop(gpointer data)
+{
+	struct module_gsettings_data *d = data;
+	if (d->loop)
+		g_main_loop_quit(d->loop);
+	return FALSE;
+}
+
+static int module_gsettings_unload(struct module *module)
+{
+	struct module_gsettings_data *d = module->user_data;
+	struct group *g;
+
+	g_main_context_invoke(d->context, do_stop, d);
+	pw_thread_utils_join(d->thr, NULL);
+	g_main_context_unref(d->context);
+
+	spa_list_consume(g, &d->groups, link)
+		unload_module(d, g);
+
+	g_strfreev(d->group_names);
+	g_object_unref(G_OBJECT(d->settings));
+	return 0;
+}
+
+static int module_gsettings_prepare(struct module * const module)
+{
+	PW_LOG_TOPIC_INIT(mod_topic);
+
+	struct module_gsettings_data * const data = module->user_data;
+	spa_list_init(&data->groups);
+	data->module = module;
+
+	return 0;
+}
+
+static const struct spa_dict_item module_gsettings_info[] = {
+	{ PW_KEY_MODULE_AUTHOR, "Wim Taymans <wim.taymans@gmail.com>" },
+	{ PW_KEY_MODULE_DESCRIPTION, "GSettings Adapter" },
+	{ PW_KEY_MODULE_VERSION, PACKAGE_VERSION },
+};
+
+DEFINE_MODULE_INFO(module_gsettings) = {
+	.name = "module-gsettings",
+	.load_once = true,
+	.prepare = module_gsettings_prepare,
+	.load = module_gsettings_load,
+	.unload = module_gsettings_unload,
+	.properties = &SPA_DICT_INIT_ARRAY(module_gsettings_info),
+	.data_size = sizeof(struct module_gsettings_data),
+};