conf: support property rules

Add pw_conf_section_update_props_rules() that will not only update the
properties of a section but wil also apply rules in section.rules and
match against the context properties.

Use this by default when using pw_context_conf_update_props().

Add a new method to get a string name of the VM type. Place the
cpu.vm.name in the context properties.

This makes it possible to deprecate the vm.overrides with something more
flexible based on rules. Update the conf files and docs to refect this.

src/daemon/minimal.conf.in

@@ -40,11 +40,6 @@ context.properties = {
     #
     settings.check-quantum      = true
     settings.check-rate         = true
-    #
-    # These overrides are only applied when running in a vm.
-    vm.overrides = {
-        default.clock.min-quantum = 1024
-    }
 
     # This config can use udev or hardcoded ALSA devices. Make sure to
     # change the alsa device below when disabling udev
@@ -54,6 +49,17 @@ context.properties = {
     minimal.use-pulse = true
 }
 
+context.properties.rules = [
+    {   matches = [ { cpu.vm.name = !null } ]
+        actions = {
+            update-props = {
+                # These overrides are only applied when running in a vm.
+                default.clock.min-quantum = 1024
+	    }
+        }
+    }
+}
+
 context.spa-libs = {
     #<factory-name regex> = <library-name>
     #

src/daemon/pipewire-avb.conf.in

@@ -67,7 +67,14 @@ avb.properties = {
     # the addresses this server listens on
     #ifname = "eth0.2"
     ifname = "enp3s0"
-    # These overrides are only applied when running in a vm.
-    vm.overrides = {
+}
+
+avb.properties.rules = [
+    {   matches = [ { cpu.vm.name = !null } ]
+        actions = {
+            update-props = {
+                # These overrides are only applied when running in a vm.
+	    }
+        }
     }
 }

src/daemon/pipewire-pulse.conf.in

@@ -110,12 +110,19 @@ pulse.properties = {
     #pulse.idle.timeout     = 0             # don't pause after underruns
     #pulse.default.format   = F32
     #pulse.default.position = [ FL FR ]
-    # These overrides are only applied when running in a vm.
-    vm.overrides = {
-        pulse.min.quantum = 1024/48000      # 22ms
-    }
 }
 
+pulse.properties.rules = [
+    {   matches = [ { cpu.vm.name = !null } ]
+        actions = {
+            update-props = {
+            # These overrides are only applied when running in a vm.
+                pulse.min.quantum = 1024/48000      # 22ms
+	    }
+        }
+    }
+]
+
 # client/stream specific properties
 pulse.rules = [
     {

src/daemon/pipewire.conf.in

@@ -40,11 +40,6 @@ context.properties = {
     #
     #settings.check-quantum      = false
     #settings.check-rate         = false
-    #
-    # These overrides are only applied when running in a vm.
-    vm.overrides = {
-        default.clock.min-quantum = 1024
-    }
 
     # keys checked below to disable module loading
     module.x11.bell = true
@@ -55,6 +50,17 @@ context.properties = {
     module.jackdbus-detect = true
 }
 
+context.properties.rules = [
+    {   matches = [ { cpu.vm.name = !null } ]
+        actions = {
+            update-props = {
+                # These overrides are only applied when running in a vm.
+                default.clock.min-quantum = 1024
+	    }
+        }
+    }
+}
+
 context.spa-libs = {
     #<factory-name regex> = <library-name>
     #

src/modules/module-avb/avb.c

@@ -32,6 +32,8 @@ struct pw_avb *pw_avb_new(struct pw_context *context,
 	pw_context_conf_update_props(context, "avb.properties", props);
 
 	if ((str = pw_properties_get(props, "vm.overrides")) != NULL) {
+		pw_log_warn("vm.overrides in avb.properties are deprecated, "
+				"use avb.properties.rules instead");
 		if (cpu != NULL && spa_cpu_get_vm_type(cpu) != SPA_CPU_VM_NONE)
 			pw_properties_update_string(props, str, strlen(str));
 		pw_properties_set(props, "vm.overrides", NULL);

src/modules/module-protocol-pulse.c

@@ -71,11 +71,17 @@
  *     #pulse.min.quantum      = 128/48000     # 2.7ms
  *     #pulse.default.format   = F32
  *     #pulse.default.position = [ FL FR ]
- *     # These overrides are only applied when running in a vm.
- *     vm.overrides = {
- *         pulse.min.quantum = 1024/48000      # 22ms
- *     }
  * }
+ * pulse.properties.rules = [
+ *     {   matches = [ { cpu.vm.name = !null } ]
+ *         actions = {
+ *             update-props = {
+ *                 # These overrides are only applied when running in a vm.
+ *                 pulse.min.quantum = 1024/48000      # 22ms
+ *             }
+ *         }
+ *     }
+ * ]
  *\endcode
  *
  * ### Connection options
@@ -185,19 +191,6 @@
  * This is equivalent to the PulseAudio `default-sample-channels` and
  * `default-channel-map` options in `/etc/pulse/daemon.conf`.
  *
- * ### VM options
- *
- *\code{.unparsed}
- *     vm.overrides = {
- *         pulse.min.quantum = 1024/48000      # 22ms
- *     }
- *\endcode
- *
- * When running in a VM, the `vm.override` section will override the properties
- * in pulse.properties with the given values. This might be interesting because
- * VMs usually can't support the low latency settings that are possible on real
- * hardware.
- *
  * ### Quirk options
  *
  *\code{.unparsed}
@@ -240,6 +233,30 @@
  *     #{ cmd = "load-module" args = "module-gsettings" flags = [ "nofail" ] }
  * ]
  *\endcode
+
+ * ## Dynamic properties
+ *
+ * The pulse.properties can be dyanmically updated with rules. It supports
+ * an `update-props` action. The matches will be performed on the values in
+ * context.properties.
+ *
+ *\code{.unparsed}
+ * pulse.properties.rules = [
+ *     {   matches = [ { cpu.vm.name = !null } ]
+ *         actions = {
+ *             update-props = {
+ *                 # These overrides are only applied when running in a vm.
+ *                 pulse.min.quantum = 1024/48000      # 22ms
+ *             }
+ *         }
+ *     }
+ * ]
+ *\endcode
+ *
+ * In the above example, when running in a VM, the rule will override the properties
+ * in pulse.properties with the given values. This might be interesting because
+ * VMs usually can't support the low latency settings that are possible on real
+ * hardware.
  *
  * ## Stream settings and rules
  *

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

@@ -5502,6 +5502,8 @@ struct pw_protocol_pulse *pw_protocol_pulse_new(struct pw_context *context,
 	pw_context_conf_update_props(context, "pulse.properties", props);
 
 	if ((str = pw_properties_get(props, "vm.overrides")) != NULL) {
+		pw_log_warn("vm.overrides in pulse.properties are deprecated, "
+				"use pulse.properties.rules instead");
 		if (cpu != NULL && spa_cpu_get_vm_type(cpu) != SPA_CPU_VM_NONE)
 			pw_properties_update_string(props, str, strlen(str));
 		pw_properties_set(props, "vm.overrides", NULL);

src/pipewire/conf.c

@@ -986,26 +986,38 @@ static int update_props(void *user_data, const char *location, const char *key,
 }
 
 SPA_EXPORT
-int pw_conf_section_update_props(const struct spa_dict *conf,
-		const char *section, struct pw_properties *props)
+int pw_conf_section_update_props_rules(const struct spa_dict *conf,
+		const struct spa_dict *context, const char *section,
+		struct pw_properties *props)
 {
 	struct data data = { .props = props };
 	int res;
 	const char *str;
+	char key[128];
 
 	res = pw_conf_section_for_each(conf, section,
 			update_props, &data);
 
 	str = pw_properties_get(props, "config.ext");
 	if (res == 0 && str != NULL) {
-		char key[128];
 		snprintf(key, sizeof(key), "%s.%s", section, str);
 		res = pw_conf_section_for_each(conf, key,
 				update_props, &data);
 	}
+	if (res == 0 && context != NULL) {
+		snprintf(key, sizeof(key), "%s.rules", section);
+		res = pw_conf_section_match_rules(conf, key, context, update_props, &data);
+	}
 	return res == 0 ? data.count : res;
 }
 
+SPA_EXPORT
+int pw_conf_section_update_props(const struct spa_dict *conf,
+		const char *section, struct pw_properties *props)
+{
+	return pw_conf_section_update_props_rules(conf, NULL, section, props);
+}
+
 static bool valid_conf_name(const char *str)
 {
 	return spa_streq(str, "null") || spa_strendswith(str, ".conf");
@@ -1208,8 +1220,8 @@ SPA_EXPORT
 int pw_context_conf_update_props(struct pw_context *context,
 		const char *section, struct pw_properties *props)
 {
-	return pw_conf_section_update_props(&context->conf->dict,
-			section, props);
+	return pw_conf_section_update_props_rules(&context->conf->dict,
+			&context->properties->dict, section, props);
 }
 
 SPA_EXPORT

src/pipewire/conf.h

@@ -24,6 +24,10 @@ int pw_conf_save_state(const char *prefix, const char *name, const struct pw_pro
 int pw_conf_section_update_props(const struct spa_dict *conf,
 		const char *section, struct pw_properties *props);
 
+int pw_conf_section_update_props_rules(const struct spa_dict *conf,
+		const struct spa_dict *context, const char *section,
+		struct pw_properties *props);
+
 int pw_conf_section_for_each(const struct spa_dict *conf, const char *section,
 		int (*callback) (void *data, const char *location, const char *section,
 			const char *str, size_t len),

src/pipewire/context.c

@@ -180,7 +180,7 @@ struct pw_context *pw_context_new(struct pw_loop *main_loop,
 	struct pw_context *this;
 	const char *lib, *str;
 	void *dbus_iface = NULL;
-	uint32_t n_support;
+	uint32_t n_support, vm_type;
 	struct pw_properties *pr, *conf;
 	struct spa_cpu *cpu;
 	int res = 0;
@@ -244,6 +244,10 @@ struct pw_context *pw_context_new(struct pw_loop *main_loop,
 	n_support = pw_get_support(this->support, SPA_N_ELEMENTS(this->support) - 6);
 	cpu = spa_support_find(this->support, n_support, SPA_TYPE_INTERFACE_CPU);
 
+	vm_type = SPA_CPU_VM_NONE;
+	if (cpu != NULL && (vm_type = spa_cpu_get_vm_type(cpu)) != SPA_CPU_VM_NONE)
+		pw_properties_set(properties, "cpu.vm.name", spa_cpu_vm_type_to_string(vm_type));
+
 	res = pw_context_conf_update_props(this, "context.properties", properties);
 	pw_log_info("%p: parsed %d context.properties items", this, res);
 
@@ -253,7 +257,9 @@ struct pw_context *pw_context_new(struct pw_loop *main_loop,
 	}
 
 	if ((str = pw_properties_get(properties, "vm.overrides")) != NULL) {
-		if (cpu != NULL && spa_cpu_get_vm_type(cpu) != SPA_CPU_VM_NONE)
+		pw_log_warn("vm.overrides in context.properties are deprecated, "
+				"use context.properties.rules instead");
+		if (vm_type != SPA_CPU_VM_NONE)
 			pw_properties_update_string(properties, str, strlen(str));
 		pw_properties_set(properties, "vm.overrides", NULL);
 	}